NZ629683B - Methods for treating conditions associated with masp-2 dependent complement activation - Google Patents
Methods for treating conditions associated with masp-2 dependent complement activationInfo
- Publication number
- NZ629683B NZ629683B NZ629683A NZ62968314A NZ629683B NZ 629683 B NZ629683 B NZ 629683B NZ 629683 A NZ629683 A NZ 629683A NZ 62968314 A NZ62968314 A NZ 62968314A NZ 629683 B NZ629683 B NZ 629683B
- Authority
- NZ
- New Zealand
- Prior art keywords
- masp
- complement
- antibody
- activation
- seq
- Prior art date
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Abstract
Discloses the use of a MASP-2 inhibitory agent which inhibits MASP-2-dependent complement activation in the manufacture of a medicament for treating a subject suffering from Degos disease or Catastrophic Antiphospholipid Syndrome (CAPS), wherein the MASP-2 inhibitory agent is a monoclonal MASP-2 inhibitory antibody, or antigen-binding fragment thereof, that specifically binds to a portion of SEQ ID NO:6 and selectively inhibits MASP-2-dependent complement activation without substantially inhibiting the C1q-dependent complement pathway, wherein the sequence is as defined in the complete specification. ibitory antibody, or antigen-binding fragment thereof, that specifically binds to a portion of SEQ ID NO:6 and selectively inhibits MASP-2-dependent complement activation without substantially inhibiting the C1q-dependent complement pathway, wherein the sequence is as defined in the complete specification.
Description
METHODS FOR TREATING CONDITIONS ASSOCIATED WITH MASP-2
DEPENDENT COMPLEMENT ACTIVATION
STATEMENT REGARDING SEQUENCE LISTING
The sequence listing associated with this application is provided in text format in lieu
of a paper copy and is hereby incorporated by reference into the specification. The name of
the text file containing the sequence listing is MP_1_0179_US_SequenceListing_20131017;
The file is 110 KB, was created on October 17, 2013 and is being submitted via EFS-Web
with the filing of the specification.
BACKGROUND
The complement system provides an early acting mechanism to initiate, amplify and
orchestrate the immune response to microbial infection and other acute insults
(M.K. Liszewski and J.P. Atkinson, 1993, in Fundamental Immunology, Third Edition,
edited by W.E. Paul, Raven Press, Ltd., New York), in humans and other vertebrates. While
complement activation provides a valuable first-line defense against potential pathogens, the
activities of complement that promote a protective immune response can also represent a
potential threat to the host (K.R. Kalli, et al., Springer Semin. Immunopathol. 15:417-431,
1994; B.P. Morgan, Eur. J. Clinical Investig. 24:219-228, 1994). For example, C3 and C5
proteolytic products recruit and activate neutrophils. While indispensable for host defense,
activated neutrophils are indiscriminate in their release of destructive enzymes and may
cause organ damage. In addition, complement activation may cause the deposition of lytic
complement components on nearby host cells as well as on microbial targets, resulting in
host cell lysis.
The complement system has also been implicated in the pathogenesis of numerous
acute and chronic disease states, including: myocardial infarction, stroke, ARDS,
reperfusion injury, septic shock, capillary leakage following thermal burns,
postcardiopulmonary bypass inflammation, transplant rejection, rheumatoid arthritis,
multiple sclerosis, myasthenia gravis, and Alzheimer's disease. In almost all of these
conditions, complement is not the cause but is one of several factors involved in
pathogenesis. Nevertheless, complement activation may be a major pathological mechanism
and represents an effective point for clinical control in many of these disease states. The
growing recognition of the importance of complement-mediated tissue injury in a variety of
disease states underscores the need for effective complement inhibitory drugs. To date,
Eculizumab (Solaris®), an antibody against C5, is the only complement-targeting drug that
has been approved for human use. Yet, C5 is one of several effector molecules located
“downstream” in the complement system, and blockade of C5 does not inhibit activation of
the complement system. Therefore, an inhibitor of the initiation steps of complement
activation would have significant advantages over a “downstream” complement inhibitor.
Currently, it is widely accepted that the complement system can be activated through
three distinct pathways: the classical pathway, the lectin pathway, and the alternative
pathway. The classical pathway is usually triggered by a complex composed of host
antibodies bound to a foreign particle (i.e., an antigen) and thus requires prior exposure to an
antigen for the generation of a specific antibody response. Since activation of the classical
pathway depends on a prior adaptive immune response by the host, the classical pathway is
part of the acquired immune system. In contrast, both the lectin and alternative pathways are
independent of adaptive immunity and are part of the innate immune system.
The activation of the complement system results in the sequential activation of serine
protease zymogens. The first step in activation of the classical pathway is the binding of a
specific recognition molecule, C1q, to antigen-bound IgG and IgM molecules. C1q is
associated with the Clr and Cls serine protease proenzymes as a complex called Cl. Upon
binding of C1q to an immune complex, autoproteolytic cleavage of the Arg-Ile site of Clr is
followed by Clr-mediated cleavage and activation of Cls, which thereby acquires the ability
to cleave C4 and C2. C4 is cleaved into two fragments, designated C4a and C4b, and,
similarly, C2 is cleaved into C2a and C2b. C4b fragments are able to form covalent bonds
with adjacent hydroxyl or amino groups and generate the C3 convertase (C4b2a) through
noncovalent interaction with the C2a fragment of activated C2. C3 convertase (C4b2a)
activates C3 by proteolytic cleavage into C3a and C3b subcomponents leading to generation
of the C5 convertase (C4b2a3b), which, by cleaving C5 leads to the formation of the
membrane attack complex (C5b combined with C6, C7, C8 and C-9, also referred to as
“MAC”) that can disrupt cellular membranes leading to cell lysis. The activated forms of C3
and C4 (C3b and C4b) are covalently deposited on the foreign target surfaces, which are
recognized by complement receptors on multiple phagocytes.
Independently, the first step in activation of the complement system through the
lectin pathway is also the binding of specific recognition molecules, which is followed by the
activation of associated serine protease proenzymes. However, rather than the binding of
immune complexes by C1q, the recognition molecules in the lectin pathway comprise a
group of carbohydrate-binding proteins (mannan-binding lectin (MBL), H-ficolin, M-ficolin,
L-ficolin and C-type lectin CL-11), collectively referred to as lectins. See J. Lu et al.,
Biochim. Biophys. Acta 1572:387-400, (2002); Holmskov et al., Annu. Rev.
Immunol. 21:547-578 (2003); Teh et al., Immunology 101:225-232 (2000)). See also J. Luet
et al., Biochim Biophys Acta 1572:387-400 (2002); Holmskov et al, Annu Rev Immunol
21:547-578 (2003); Teh et al., Immunology 101:225-232 (2000); Hansen et al, J. Immunol
185(10):6096-6104 (2010).
Ikeda et al. first demonstrated that, like C1q, MBL could activate the complement
system upon binding to yeast mannan-coated erythrocytes in a C4-dependent manner (Ikeda
et al., J. Biol. Chem. 262:7451-7454, (1987)). MBL, a member of the collectin protein
family, is a calcium-dependent lectin that binds carbohydrates with 3- and 4-hydroxy groups
oriented in the equatorial plane of the pyranose ring. Prominent ligands for MBL are thus
D-mannose and N-acetyl-D-glucosamine, while carbohydrates not fitting this steric
requirement have undetectable affinity for MBL (Weis et al., Nature 360:127-134, (1992)).
The interaction between MBL and monovalent sugars is extremely weak, with dissociation
constants typically in the single-digit millimolar range. MBL achieves tight, specific binding
to glycan ligands by avidity, i.e., by interacting simultaneously with multiple
monosaccharide residues located in close proximity to each other (Lee et al., Archiv.
Biochem. Biophys. 299:129-136, (1992)). MBL recognizes the carbohydrate patterns that
commonly decorate microorganisms such as bacteria, yeast, parasites and certain viruses. In
contrast, MBL does not recognize D-galactose and sialic acid, the penultimate and ultimate
sugars that usually decorate "mature" complex glycoconjugates present on mammalian
plasma and cell surface glycoproteins. This binding specificity is thought to promote
recognition of “foreign” surfaces and help protect from “self-activation.” However, MBL
does bind with high affinity to clusters of high-mannose "precursor" glycans on N-linked
glycoproteins and glycolipids sequestered in the endoplasmic reticulum and Golgi of
mammalian cells (Maynard et al., J. Biol. Chem. 257:3788-3794, (1982)). Therefore,
damaged cells are potential targets for lectin pathway activation via MBL binding.
The ficolins possess a different type of lectin domain than MBL, called the
fibrinogen-like domain. Ficolins bind sugar residues in a Ca++-independent manner. In
humans, three kinds of ficolins (L-ficolin, M-ficolin and H-ficolin) have been identified. The
two serum ficolins, L-ficolin and H-ficolin, have in common a specificity for
N-acetyl-D-glucosamine; however, H-ficolin also binds N-acetyl-D-galactosamine. The
difference in sugar specificity of L-ficolin, H-ficolin, CL-11, and MBL means that the
different lectins may be complementary and target different, though overlapping,
glycoconjugates. This concept is supported by the recent report that, of the known lectins in
the lectin pathway, only L-ficolin binds specifically to lipoteichoic acid, a cell wall
glycoconjugate found on all Gram-positive bacteria (Lynch et al., J. Immunol.
172:1198-1202, (2004)). The collectins (i.e., MBL) and the ficolins bear no significant
similarity in amino acid sequence. However, the two groups of proteins have similar domain
organizations and, like C1q, assemble into oligomeric structures, which maximize the
possibility of multisite binding.
The serum concentrations of MBL are highly variable in healthy populations and this
is genetically controlled by polymorphisms/mutations in both the promoter and coding
regions of the MBL gene. As an acute phase protein, the expression of MBL is further
upregulated during inflammation. L-ficolin is present in serum at concentrations similar to
those of MBL. Therefore, the L-ficolin branch of the lectin pathway is potentially
comparable to the MBL arm in strength. MBL and ficolins can also function as opsonins,
which allow phagocytes to target MBL- and ficolin-decorated surfaces (see Jack et al., J
Leukoc Biol., 77(3):328-36 (2004), Matsushita and Fujita, Immunobiology, 205(4-5):490-7
(2002), Aoyagi et al., J Immunol, 174(1):418-25(2005). This opsonization requires the
interaction of these proteins with phagocyte receptors (Kuhlman et al., J. Exp. Med.
169:1733, (1989); Matsushita et al., J. Biol. Chem. 271:2448-54, (1996)), the indentity of
which has not been established.
Human MBL forms a specific and high-affinity interaction through its collagen-like
domain with unique C1r/Cls-like serine proteases, termed MBL-associated serine proteases
(MASPs). To date, three MASPs have been described. First, a single enzyme "MASP" was
identified and characterized as the enzyme responsible for the initiation of the complement
cascade (i.e., cleaving C2 and C4) (Matsushita et al., J Exp Med 176(6):1497-1502 (1992); Ji
et al., J. Immunol. 150:571-578, (1993)). It was subsequently determined that the MASP
activity was, in fact, a mixture of two proteases: MASP-1 and MASP-2 (Thiel et al., Nature
386:506-510, (1997)). However, it was demonstrated that the MBL-MASP-2 complex alone
is sufficient for complement activation (Vorup-Jensen et al., J. Immunol. 165:2093-2100,
(2000)). Furthermore, only MASP-2 cleaved C2 and C4 at high rates (Ambrus et al.,
J. Immunol. 170:1374-1382, (2003)). Therefore, MASP-2 is the protease responsible for
activating C4 and C2 to generate the C3 convertase, C4b2a. This is a significant difference
from the C1 complex of the classical pathway, where the coordinated action of two specific
serine proteases (C1r and C1s) leads to the activation of the complement system. In addition,
a third novel protease, MASP-3, has been isolated (Dahl, M.R., et al., Immunity 15:127-35,
2001). MASP-1 and MASP-3 are alternatively spliced products of the same gene.
MASPs share identical domain organizations with those of Clr and Cls, the enzymatic
components of the Cl complex (Sim et al., Biochem. Soc. Trans. 28:545, (2000)). These
domains include an N-terminal Clr/Cls/sea urchin VEGF/bone morphogenic protein (CUB)
domain, an epidermal growth factor-like domain, a second CUB domain, a tandem of
complement control protein domains, and a serine protease domain. As in the C1 proteases,
activation of MASP-2 occurs through cleavage of an Arg-I1e bond adjacent to the serine
protease domain, which splits the enzyme into disulfide-linked A and B chains, the latter
consisting of the serine protease domain.
MBL can also associate with an alternatively sliced form of MASP-2, known as
MBL-associated protein of 19 kDa (MAp19) or small MBL-associated protein (sMAP),
which lacks the catalytic acivity of MASP2. (Stover, J. Immunol. 162:3481-90, (1999);
Takahashi et al., Int. Immunol. 11:859-863, (1999)). MAp19 comprises the first two
domains of MASP-2, followed by an extra sequence of four unique amino acids. The
function of Map19 is unclear (Degn et al., J Immunol. Methods, 2011). The MASP-1 and
MASP-2 genes are located on human chromosomes 3 and 1, respectively (Schwaeble et al.,
Immunobiology 205:455-466, (2002)).
Several lines of evidence suggest that there are different MBL-MASP complexes and
a large fraction of the MASPs in serum is not complexed with MBL (Thiel, et al., J.
Immunol. 165:878-887, (2000)). Both H- and L-ficolin bind to all MASPs and activate the
lectin complement pathway, as does MBL (Dahl et al., Immunity 15:127-35, (2001);
Matsushita et al., J. Immunol. 168:3502-3506, (2002)). Both the lectin and classical
pathways form a common C3 convertase (C4b2a) and the two pathways converge at this
step.
The lectin pathway is widely thought to have a major role in host defense against
infection in the naïve host. Strong evidence for the involvement of MBL in host defense
comes from analysis of patients with decreased serum levels of functional MBL (Kilpatrick,
Biochim. Biophys. Acta 1572:401-413, (2002)). Such patients display susceptibility to
recurrent bacterial and fungal infections. These symptoms are usually evident early in life,
during an apparent window of vulnerability as maternally derived antibody titer wanes, but
before a full repertoire of antibody responses develops. This syndrome often results from
mutations at several sites in the collagenous portion of MBL, which interfere with proper
formation of MBL oligomers. However, since MBL can function as an opsonin independent
of complement, it is not known to what extent the increased susceptibility to infection is due
to impaired complement activation.
In contrast to the classical and lectin pathways, no initiators of the alternative
pathway have been found to fulfill the recognition functions that C1q and lectins perform in
the other two pathways. Currently it is widely accepted that the alternative pathway
spontaneously undergoes a low level of turnover activation, which can be readily amplified
on foreign or other abnormal surfaces (bacteria, yeast, virally infected cells, or damaged
tissue) that lack the proper molecular elements that keep spontaneous complement activation
in check. There are four plasma proteins directly involved in the activation of the alternative
pathway: C3, factors B and D, and properdin.
Although there is extensive evidence implicating both the classical and alternative
complement pathways in the pathogenesis of non-infectious human diseases, the role of the
lectin pathway is just beginning to be evaluated. Recent studies provide evidence that
activation of the lectin pathway can be responsible for complement activation and related
inflammation in ischemia/reperfusion injury. Collard et al. (2000) reported that cultured
endothelial cells subjected to oxidative stress bind MBL and show deposition of C3 upon
exposure to human serum (Collard et al., Am. J. Pathol. 156:1549-1556, (2000)). In
addition, treatment of human sera with blocking anti-MBL monoclonal antibodies inhibited
MBL binding and complement activation. These findings were extended to a rat model of
myocardial ischemia-reperfusion in which rats treated with a blocking antibody directed
against rat MBL showed significantly less myocardial damage upon occlusion of a coronary
artery than rats treated with a control antibody (Jordan et al., Circulation 104:1413-1418,
(2001)). The molecular mechanism of MBL binding to the vascular endothelium after
oxidative stress is unclear; a recent study suggests that activation of the lectin pathway after
oxidative stress may be mediated by MBL binding to vascular endothelial cytokeratins, and
not to glycoconjugates (Collard et al., Am. J. Pathol. 159:1045-1054, (2001)). Other studies
have implicated the classical and alternative pathways in the pathogenesis of
ischemia/reperfusion injury and the role of the lectin pathway in this disease remains
controversial (Riedermann, N.C., et al., Am. J. Pathol. 162:363-367, 2003).
A recent study has shown that MASP-1 (and possibly also MASP-3) is required to
convert the alternative pathway activation enzyme Factor D from its zymogen form into its
enzymatically active form (see Takahashi M. et al., J Exp Med 207(1):29-37 (2010)). The
physiological importance of this process is underlined by the absence of alternative pathway
functional activity in plasma of MASP-1/3-deficient mice. Proteolytic generation of C3b
from native C3 is required for the alternative pathway to function. Since the alternative
pathway C3 convertase (C3bBb) contains C3b as an essential subunit, the question regarding
the origin of the first C3b via the alternative pathway has presented a puzzling problem and
has stimulated considerable research.
C3 belongs to a family of proteins (along with C4 and α-2 macroglobulin) that
contain a rare posttranslational modification known as a thioester bond. The thioester group
is composed of a glutamine whose terminal carbonyl group forms a covalent thioester
linkage with the sulfhydryl group of a cysteine three amino acids away. This bond is
unstable and the electrophilic glutamyl-thioester can react with nucleophilic moieties such as
hydroxyl or amino groups and thus form a covalent bond with other molecules. The thioester
bond is reasonably stable when sequestered within a hydrophobic pocket of intact C3.
However, proteolytic cleavage of C3 to C3a and C3b results in exposure of the highly
reactive thioester bond on C3b and, following nucleophilic attack by adjacent moieties
comprising hydroxyl or amino groups, C3b becomes covalently linked to a target. In
addition to its well-documented role in covalent attachment of C3b to complement targets,
the C3 thioester is also thought to have a pivotal role in triggering the alternative pathway.
According to the widely accepted "tick-over theory", the alternative pathway is initiated by
the generation of a fluid-phase convertase, iC3Bb, which is formed from C3 with hydrolyzed
thioester (iC3; C3(H2O)) and factor B (Lachmann, P.J., et al., Springer Semin.
Immunopathol. 7:143-162, (1984)). The C3b-like C3(H2O) is generated from native C3 by a
slow spontaneous hydrolysis of the internal thioester in the protein (Pangburn, M.K., et al., J.
Exp. Med. 154:856-867, 1981). Through the activity of the C3(H2O)Bb convertase, C3b
molecules are deposited on the target surface thereby initiating the alternative pathway.
Very little is known about the initiators of activation of the alternative pathway.
Activators are thought to include yeast cell walls (zymosan), many pure polysaccharides,
rabbit erythrocytes, certain immunoglobulins, viruses, fungi, bacteria, animal tumor cells,
parasites, and damaged cells. The only feature common to these activators is the presence of
carbohydrate, but the complexity and variety of carbohydrate structures has made it difficult
to establish the shared molecular determinants which are recognized. It has been widely
accepted that alternative pathway activation is controlled through the fine balance between
inhibitory regulatory components of this pathway, such as Factor H, Factor I, DAF, and CR1,
and properdin, which is the only positive regulator of the alternative pathway (see Schwaeble
W.J. and Reid K.B., Immunol Today 20(1):17-21 (1999)).
In addition to the apparently unregulated activation mechanism described above, the
alternative pathway can also provide a powerful amplification loop for the lectin/classical
pathway C3 convertase (C4b2a) since any C3b generated can participate with factor B in
forming additional alternative pathway C3 convertase (C3bBb). The alternative pathway C3
convertase is stabilized by the binding of properdin. Properdin extends the alternative
pathway C3 convertase half-life six to ten fold. Addition of C3b to the alternative pathway
C3 convertase leads to the formation of the alternative pathway C5 convertase.
All three pathways (i.e., the classical, lectin and alternative) have been thought to converge at
C5, which is cleaved to form products with multiple proinflammatory effects. The converged
pathway has been referred to as the terminal complement pathway. C5a is the most potent
anaphylatoxin, inducing alterations in smooth muscle and vascular tone, as well as vascular
permeability. It is also a powerful chemotaxin and activator of both neutrophils and monocytes.
C5a-mediated cellular activation can significantly amplify inflammatory responses by inducing the
release of multiple additional inflammatory mediators, including cytokines, hydrolytic enzymes,
arachidonic acid metabolites, and reactive oxygen species. C5 cleavage leads to the formation of
C5b-9, also known as the membrane attack complex (MAC). There is now strong evidence that
sublytic MAC deposition may play an important role in inflammation in addition to its role as a lytic
pore-forming complex.
In addition to its essential role in immune defense, the complement system contributes to
tissue damage in many clinical conditions. Thus, there is a pressing need to develop therapeutically
effective complement inhibitors to prevent these adverse effects.
SUMMARY
NZ 716896 was divided from the present application. The complete description of the
present invention and the invention of NZ 716896 is retained herein for clarity and completeness.
This summary is provided to introduce a selection of concepts in a simplified form that are
further described below in the Detailed Description. This summary is not intended to identify key
features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope
of the claimed subject matter.
In one aspect, the present invention provides a method of inhibiting the adverse effects of
MASPdependent complement activation in a living subject. The method includes the step of
administering to a subject in need thereof, an amount of a MASP-2 inhibitory agent effective to
inhibit MASPdependent complement activation. In another aspect of the invention, the MASP-2
inhibitory agent inhibits complement activation via the lectin-dependent MASP-2 system without
substantially inhibiting complement activation via the classical or C1q-dependent system, such that
the C1q-dependent system remains functional.
In some embodiments of these aspects of the invention, the MASP-2 inhibitory agent is an
anti-MASP-2 antibody or fragment thereof. In further embodiments, the anti-MASP-2
antibody has reduced effector function. In some embodiments, the MASP-2 inhibitory agent
is a MASP-2 inhibitory peptide or a non-peptide MASP-2 inhibitor.
In another aspect, the present invention provides compositions for inhibiting the
adverse effects of MASPdependent complement activation, comprising a therapeutically
effective amount of a MASP-2 inhibitory agent and a pharmaceutically acceptable carrier.
Methods are also provided for manufacturing a medicament for use in inhibiting the adverse
effects of MASPdependent complement activation in living subjects in need thereof,
comprising a therapeutically effective amount of a MASP-2 inhibitory agent in a
pharmaceutical carrier. Methods are also provided for manufacturing medicaments for use in
inhibiting MASPdependent complement activation for treatment of each of the conditions,
diseases and disorders described herein below.
The methods, compositions and medicaments of the invention are useful for
inhibiting the adverse effects of MASPdependent complement activation in vivo in
mammalian subjects, including humans suffering from an acute or chronic pathological
condition or injury as further described herein. .
In another aspect of the invention, methods are provided for inhibiting MASP
dependent complement activation in a subject suffering from paroxysmal nocturnal
hemoglobinuria, comprising administering to the subject a composition comprising an
amount of a MASP-2 inhibitory agent effective to inhibit MASP-2 dependent complement
activation.
In another aspect, the invention provides a method of inhibiting MASPdependent
complement activation in a subject suffering from or at risk for developing non-Factor Hdependent atypical hemolytic uremic syndrome (aHUS), comprising administering to the
subject a composition comprising an amount of a MASP-2 inhibitory agent effective to
inhibit MASP-2 dependent complement activation.
In another aspect, the invention provides a method for reducing the likelihood that a
subject at risk for developing atypical hemolytic uremic syndrome (aHUS) will suffer
clinical symptoms associated with aHUS comprising:(a) determining the presence of a
genetic marker in the subject known to be associated with aHUS; (b) periodically monitoring
the subject to determine the presence or absence of at least one symptom selected from the
group consisting of anemia, thrombocytopenia, renal insufficiency and rising creatinine; and
(c) administering to the subject a composition comprising an amount of a MASP-2 inhibitory
agent effective to inhibit MASPdependent complement activation upon the determination
of the presence of at least one of anemia, thrombocytopenia, renal insufficiency or rising
creatinine, wherein the composition is administered in an effective amount and for a
sufficient time period to improve said one or more symptoms.
In another aspect, the invention provides a method of inhibiting MASPdependent
complement activation in a subject suffering from, or at risk for developing, atypical
hemolytic uremic syndrome (aHUS) secondary to an infection, comprising administering to
the subject a composition comprising an amount of a MASP-2 inhibitory agent effective to
inhibit MASP-2 complement activation.
In another aspect, the invention provides a method of treating a subject suffering from
atypical hemolytic uremic syndrome (aHUS) comprising administering to the subject a
composition comprising an amount of a MASP-2 inhibitory agent effective to inhibit MASP2 dependent complement activation, wherein the administration of the MASP-2 inhibitory
agent is administered via an intravenous catheter or other catheter delivery method.
In another aspect, the invention provides a method for decreasing the likelihood of
developing impaired renal function in a subject at risk for developing hemolytic uremic
syndrome (HUS) comprising administering to the subject a composition comprising an
amount of a MASP-2 inhibitory agent effective to inhibit MASP-2 dependent complement
activation.
In another aspect, the invention provides a method of treating a subject suffering from
hemolytic uremic syndrome (HUS) comprising administering to the subject a composition
comprising an amount of a MASP-2 inhibitory agent effective to inhibit MASPdependent
complement activation, wherein the administration of the MASP-2 inhibitory agent is
administered to the subject via an intravenous catheter or other catheter delivery method.
In another aspect, the invention provides a method of treating a subject suffering from
thrombotic thrombocytopenic purpura (TTP), or exhibiting symptoms consistent with a
diagnosis of TTP, comprising administering to the subject a composition comprising an
amount of a MASP-2 inhibitory agent effective to inhibit MASPdependent complement
activation, wherein the administration of the MASP-2 inhibitory agent is administered to the
subject via an intravenous catheter or other catheter delivery method.
In another aspect, the invention provides a method of treating a subject suffering from
refractory thrombotic thrombocytopenic purpura (TTP) comprising administering to the
subject a composition comprising an amount of a MASP-2 inhibitory agent effective to
inhibit MASP-2 dependent complement activation.
In another aspect, the invention provides a method of inhibiting MASPdependent
complement activation in a subject suffering from or at risk for developing UpshawSchulman Syndrome (USS) comprising administering to the subject a composition
comprising an amount of a MASP-2 inhibitory agent effective to inhibit MASP-2 dependent
complement activation.
In another aspect, the invention provides a method for reducing the likelihood that a
subject with Upshaw-Schulman syndrome (USS) will suffer clinical symptoms associated
with congential TTP comprising administering an amount of a MASP-2 inhibitory agent for
a time period effective to ameliorate or prevent one of more clinical symptoms associated
with TTP. In some embodiments, the method further comprises periodically monitoring the
subject and administering the MASP-2 inhibitory agent upon the determination of the
presence of anemia, thrombocytopenia or rising creatine. In some embodiments, the method
further comprises periodically monitoring the subject and administering the MASP-2
inhibitory agent upon the presence of an event known to be associated with triggering TTP
clinical symptoms.
In another aspect, the invention provides a method of treating a subject suffering from
Degos disease, comprising administering to the subject a composition comprising an amount
of a MASP-2 inhibitory agent effective to inhibit MASPdependent complement
activation.
In another aspect, the invention provides a method of treating a subject suffering from
Catastrophic Antiphospholipid Syndrome (CAPS), comprising administering to the subject a
composition comprising an amount of a MASP-2 inhibitory agent effective to inhibit MASP2-dependent complement activation.
In another aspect, the invention provides a method of treating a subject suffering
from, or at risk for developing a thrombotic microangiopathy (TMA), wherein the TMA is at
least one of (i) a TMA secondary to cancer; (ii) a TMA secondary to chemotherapy, or (iii) a
TMA secondary to transplantation, comprising administering to the subject a composition
comprising an amount of a MASP-2 inhibitory agent effective to inhibit MASPdependent
complement activation. In one embodiment, the subject is suffering from, or is at risk for
developing, a TMA secondary to cancer, and the MASP-2 inhibitory agent is administered
systemically to the subject in an amount effective to reduce the risk of developing TMA, or
reduce the severity of TMA. In one embodiment, the subject is suffering from, or is at risk
for developing a TMA secondary to chemotherapy, and the MASP-2 inhibitory agent is
administered systemically to the subject prior to, during, or after chemotherapy, in an amount
effective to reduce the risk of developing TMA, or reduce the severity of TMA. In one
embodiment, the subject is suffering from, or is at risk for developing, a TMA secondary to
transplantation, and the MASP-2 inhibitory agent is administered systemically to the subject
prior to, during, or after the transplant procedure, in an amount effective to reduce the risk of
developing TMA, or reduce the severity of TMA.
In another aspect of the invention, methods are provided for inhibiting MASP
dependent complement activation in a subject suffering from cryoglobulinemia, comprising
administering to the subject a composition comprising an amount of a MASP-2 inhibitory
agent effective to inhibit MASP-2 dependent complement activation.
In another aspect of the invention, methods are provided for inhibiting MASP
dependent complement activation in a subject suffering from cold aggultinin disease,
comprising administering to the subject a composition comprising an amount of a MASP-2
inhibitory agent effective to inhibit MASP-2 dependent complement activation.
In another aspect of the invention, methods are provided for inhibiting MASP-2
dependent complement activation in a subject suffering from glaucoma, comprising
administering to the subject a composition comprising an amount of a MASP-2 inhibitory
agent effective to inhibit MASP-2 dependent complement activation.
In another aspect of the invention, methods are provided for inhibiting MASP-2
dependent complement activation in a subject at risk for developing or suffering from acute
radiation syndrome comprising administering to the subject a composition comprising an
amount of a MASP-2 inhibitory agent effective to inhibit MASP-2 dependent complement
activation. In some embodiments, the anti-MASP-2 inhibitory agent is an anti-MASP-2
antibody. In some embodiments, the MASP-2 inhibitory agent is administered
prophylactically to the subject prior to radiation exposure (such as prior to treatment with
radiation, or prior to an expected exposure to radiation). In some embodiments, the MASP-2
inhibitory agent is administered within 24 to 48 hours after exposure to radiation. In some
embodiments, the MASP-2 inhibitory agent is administered prior to and/or after exposure to
radiation in an amount sufficient to ameliorate one or more symptoms associated with acute
radiation syndrome.
DESCRIPTION OF THE DRAWINGS
The foregoing aspects and many of the attendant advantages of this invention will
become more readily appreciated as the same become better understood by reference to the
following detailed description, when taken in conjunction with the accompanying drawings,
wherein:
FIGURE 1 is a diagram illustrating the genomic structure of human MASP-2;
FIGURE 2A is a schematic diagram illustrating the domain structure of human
MASP-2 protein;
FIGURE 2B is a schematic diagram illustrating the domain structure of human
MAp19 protein;
FIGURE 3 is a diagram illustrating the murine MASP-2 knockout strategy;
FIGURE 4 is a diagram illustrating the human MASP-2 minigene construct;
FIGURE 5A presents results demonstrating that MASPdeficiency leads to the loss
of lectin-pathway-mediated C4 activation as measured by lack of C4b deposition on mannan,
as described in Example 2;
FIGURE 5B presents results demonstrating that MASPdeficiency leads to the loss
of lectin-pathway-mediated C4 activation as measured by lack of C4b deposition on
zymosan, as described in Example 2;
FIGURE 5C presents results demonstrating the relative C4 activation levels of serum
samples obtained from MASP-2+/-; MASP/- and wild-type strains as measure by C4b
deposition on mannan and on zymosan, as described in Example 2;
FIGURE 6 presents results demonstrating that the addition of murine recombinant
MASP-2 to MASP/- serum samples recovers lectin-pathway-mediated C4 activation in a
protein concentration dependant manner, as measured by C4b deposition on mannan, as
described in Example 2;
FIGURE 7 presents results demonstrating that the classical pathway is functional in
the MASP/- strain, as described in Example 8;
FIGURE 8A presents results demonstrating that anti-MASP-2 Fab2 antibody #11
inhibits C3 convertase formation, as described in Example 10;
FIGURE 8B presents results demonstrating that anti-MASP-2 Fab2 antibody #11
binds to native rat MASP-2, as described in Example 10;
FIGURE 8C presents results demonstrating that anti-MASP-2 Fab2 antibody #41
inhibits C4 cleavage, as described in Example 10;
FIGURE 9 presents results demonstrating that all of the anti-MASP-2 Fab2
antibodies tested that inhibited C3 convertase formation also were found to inhibit C4
cleavage, as described in Example 10;
FIGURE 10 is a diagram illustrating the recombinant polypeptides derived from rat
MASP-2 that were used for epitope mapping of the anti-MASP-2 blocking Fab2 antibodies,
as described in Example 11;
FIGURE 11 presents results demonstrating the binding of anti-MASP-2 Fab2 #40 and
#60 to rat MASP-2 polypeptides, as described in Example 11;
FIGURE 12 presents results demonstrating the blood urea nitrogen clearance for wild
type (+/+) and MASP-2 (-/-) mice at 24 and 48 hours after reperfusion in a renal
ischemia/reperfusion injury model, as described in Example 12;
FIGURE 13A presents results showing the baseline VEGF protein levels in
RPE-choroid complex isolated from wild type (+/+) and MASP-2 (-/-) mice, as described in
Example 13;
FIGURE 13B presents results showing the VEGF protein levels in RPE-choroid
complex at day 3 in wild type (+/+) and MASP-2 (-/-) mice following laser induced injury in
a macular degeneration model, as described in Example 13;
FIGURE 14 presents results showing the mean choroidal neovascularization (CNV)
volume at day seven following laser induced injury in wild type (+/+) and MASP-2 (-/-)
mice, as described in Example 13;
FIGURES 15A and 15B present dose response curves for the inhibition of C4b
deposition (FIG. 15A) and the inhibition of thrombin activation (FIG 15B) following the
administration of a MASP-2 Fab2 antibody in normal rat serum, as described in Example 14;
FIGURES 16A and 16B present measured platelet aggregation (expressed as
aggregate area) in MASP-2 (-/-) mice (FIG. 16B) as compared to platelet aggregation in
untreated wild type mice and wild type mice in which the complement pathway is inhibited
by depletory agent cobra venom factor (CVF) and a terminal pathway inhibitor (C5aR
antagonist) (FIGURE 16A) in a localized Schwartzman reaction model of disseminated
intravascular coagulation, as described in Example 15;
FIGURE 17 graphically illustrates the blood urea nitrogen (BUN) levels measured in
either WT (+/+) (B6) or MASP-2 (-/-) transplant recipient mice of WT (+/+) donor kidneys,
as described in Example 16;
FIGURE 18 graphically illustrates the percentage survival of WT (+/+) and MASP-2
(-/-) mice as a function of the number of days after microbial infection in the cecal ligation
and puncture (CLP) model, as described in Example 17;
FIGURE 19 graphically illustrates the number of bacteria measured in WT (+/+) and
MASP-2 (-/-) after microbial infection in the cecal ligation and puncture (CLP) model, as
described in Example 17;
FIGURE 20 is a Kaplan-Mayer plot illustrating the percent survival of WT (+/+),
MASP-2 (-/-) and C3 (-/-) mice six days after challenge with intranasal administration of
Pseudomonas aeruginosa, as described in Example 18;
FIGURE 21 graphically illustrates the level of C4b deposition, measured as % of
control, in samples taken at various time points after subcutaneous dosing of either 0.3 mg/kg
or 1.0 mg/kg of mouse anti-MASP-2 monoclonal antibody in WT mice, as described in
Example 19;
FIGURE 22 graphically illustrates the level of C4b deposition, measured as % of
control, in samples taken at various time points after ip dosing of 0.6 mg/kg of mouse anti25 MASP-2 monoclonal antibody in WT mice, as described in Example 19;
FIGURE 23 graphically illustrates the mean choroidal neovascularization (CNV)
volume at day seven following laser induced injury in WT (+/+) mice pre-treated with a
single ip injection of 0.3 mg/kg or 1.0 mg/kg mouse anti-MASP-2 monoclonal antibody; as
described in Example 20;
FIGURE 24A graphically illustrates the percent survival of MASP-2 (-/-) and WT
(+/+) mice after infection with 5x108/100 μl cfu N. meningitidis, as described in Example 21;
FIGURE 24B graphically illustrates the log cfu/ml of N. meningitidis recovered at
different time points in blood samples taken from the MASP-2 KO (-/-) and WT (+/+) mice
infected with 5x108 cfu/100 μl N. meningitidis, as described in Example 21;
FIGURE 25A graphically illustrates the percent survival of MASP-2 KO (-/-) and
WT (+/+) mice after infection with 2x108 5 cfu/100 μl N. meningitidis, as described in
Example 21;
FIGURE 25B graphically illustrates the log cfu/ml of N. meningitidis recovered at
different time points in blood samples taken from the WT (+/+) mice infected with 2x108
cfu/100 μl N. meningitidis, as described in Example 21;
FIGURE 25C graphically illustrates the log cfu/ml of N. meningitidis recovered at
different time points in blood samples taken from the MASP-2 (-/-) mice infected with 2x108
cfu/100 μl N. meningitidis, as described in Example 21;
FIGURE 26A graphically illustrates the results of a C3b deposition assay
demonstrating that MASP-2 (-/-) mice retain a functional classical pathway, as described in
Example 22;
FIGURE 26B graphically illustrates the results of a C3b deposition assay on zymosan
coated plates, demonstrating that MASP-2 (-/-) mice retain a functional alternative pathway,
as described in Example 22;
FIGURE 27A graphically illustrates myocardial ischemia/reperfusion injury (MIRI)-
induced tissue loss following ligation of the left anterior descending branch of the coronary
artery (LAD) and reperfusion in C4 (-/-) mice (n=6) and matching WT littermate controls
(n=7), showing area at risk (AAR) and infarct size (INF) as described in Example 22;
FIGURE 27B graphically illustrates infarct size (INF) as a function of area at risk
(AAR) in C4 (-/-) and WT mice treated as describe in FIGURE 42A, demonstrating that C4
(-/-) mice are as susceptible to MIRI as WT controls (dashed line), as described in Example
22;
FIGURE 28A graphically illustrates the results of a C3b deposition assay using serum
from WT mice, C4 (-/-) mice and serum from C4 (-/-) mice pre-incubated with mannan, as
described in Example 22;
FIGURE 28B graphically illustrates the results of a C3b deposition assay on serum
from WT, C4 (-/-), and MASP-2 (-/-) mice mixed with various concentrations of an antimurine MASP-2 mAb (mAbM11), as described in Example 22;
FIGURE 28C graphically illustrates the results of a C3b deposition assay on human
serum from WT (C4 sufficient) and C4 deficient serum, and serum from C4 deficient
subjects pre-incubated with mannan, as described in Example 22;
FIGURE 28D graphically illustrates the results of a C3b deposition assay on human
serum from WT (C4 sufficient) and C4 deficient subjects mixed with anti-human MASP-2
mAb (mAbH3), as described in Example 22;
FIGURE 29A graphically illustrates a comparative analysis of C3 convertase activity
in plasma from various complement deficient mouse strains tested either under lectin
activation pathway specific assay conditions, or under classical activation pathway specific
assay conditions, as described in Example 22;
FIGURE 29B graphically illustrates the time-resolved kinetics of C3 convertase
activity in plasma from various complement deficient mouse strains tested under lectin
activation pathway specific conditions, as described in Example 22;
FIGURE 30 illustrates the results of a Western blot analysis showing activation of
human C3, shown by the presence of the a' chain, by thrombin substrates FXIa and FXa, as
described in Example 23;
FIGURE 31 shows the results of the C3 deposition assay on serum samples obtained
from WT, MASP-2 (-/-), F11(-/-), F11(-/-)/C4 (-/-) and C4 (-/-), as described in Example 23;
FIGURE 32A is a Kaplain-Meier survival plot showing the percent survival over time
after exposure to 7.0 Gy radiation in control mice and in mice treated with anti-murine
MASP-2 antibody (mAbM11) or anti-human MASP-2 antibody (mAbH6) as described in
Example 29;
FIGURE 32B is a Kaplain-Meier survival plot showing the percent survival over time
after exposure to 6.5 Gy radiation in control mice and in mice treated with anti-murine
MASP-2 antibody (mAbM11) or anti-human MASP-2 antibody (mAbH6), as described in
Example 29;
FIGURE 33 is a Kaplan-Meyer plot graphically illustrating the percent survival of
MASP-2 KO and WT mice after administration of an infective dose of 2.6 x 107 cfu of N.
meningitidis serogroup A Z2491, demonstrating that MASP-2 deficient mice are protected
from N. meningitidis induced mortality, as described in Example 30;
FIGURE 34 is a Kaplan-Meyer plot graphically illustrating the percent survival of
MASP-2 KO and WT mice after administration of an infective dose of 6 x 106 cfu of N.
meningitidis serogroup B strain MC58, demonstrating that MASPdeficient mice are
protected from N. meningitidis serogroup B strain MC58 induced mortality, as described in
Example 30;
FIGURE 35 graphically illustrates the log cfu/ml of N. meningitidis serogroup B
strain MC58 recovered at different time points in blood samples taken from the MASP-2 KO
and WT mice after i.p. infection with 6x106 10 cfu of N. meningitidis serogroup B strain MC58
(n=3 at different time points for both groups of mice, results are expressed as Means±SEM)
demonstrating that although the MASP-2 KO mice were infected with the same dose of N.
meningitidis serogroup B strain MC58 as the WT mice, the MASP-2 KO mice have
enhanced clearance of bacteraemia as compared to WT, as described in Example 30;
FIGURE 36 graphically illustrates the average illness score of MASP-2 and WT mice
at 3, 6, 12 and 24 hours after infection with 6x106 cfu/100 μl N. meningitidis Serogroup
Serogroup B strain MC58, demonstrating that the MASP-2 deficient mice showed high
resistance to the infection, with much lower illness scores at 6 hours, as described in
Example 30;
FIGURE 37 is a Kaplan-Meyer plot graphically illustrating the percent survival of
mice after administration of an infective dose of 4 x 106/100 μl cfu N. meningitidis
Serogroup B strain MC58, followed by administration 3 hours post infection of either
inhibitory anti-MASP-2 antibody (1 mg/kg) or control isotype antibody, demonstrating that
anti-MASP-2 antibody is effective to treat and improve survival in subjects infected with N.
meningitidis, as described in Example 31;
FIGURE 38 graphically illustrates the log cfu/ml of viable counts of N. meningitidis
serogroup B-MC58 recovered at different time points in 20% human serum concentration
after i.p. infection with 6.5x106 cfu/100 μl N. meningitidis serogroup B strain MC58 at 0, 30,
60 and 90 minutes after incubation in the presence of: (A) normal human serum (NHS) plus
human anti-MASP-2 antibody; (B) normal human serum (NHS) plus isotype control
antibody; (C) MBL-/- human serum; (D) normal human serum (NHS) and (E) heat
inactivated normal human serum (NHS), showing that complement dependent killing of N.
meningitidis in human serum was significantly enhanced by the addition of the human antiMASP-2 antibody, as described in Example 32;
FIGURE 39 graphically illustrates the log cfu/ml of viable counts of N. meningitidis
serogroup B-MC58 recovered at different time points in the mouse sera samples,
demonstrating MASP-2 -/- mouse sera has a higher level of bactericidal activity for N.
meningitidis than WT mouse sera, as described in Example 32;
FIGURE 40 graphically illustrates hemolysis (as measured by hemoglobin release of
lysed mouse erythrocytes (Crry/C3-/-) into the supernatant measured by photometry) of
mannan-coated murine erythrocytes by human serum over a range of serum concentrations
The sera tested included heat-inactivated (HI) NHS, MBL-/-, NHS +anti-MASP-2 antibody
and NHS control, as described in Example 33;
FIGURE 41 graphically illustrates hemolysis (as measured by hemoglobin release of
lysed WT mouse erythrocytes into the supernatant measured by photometry) of non-coated
murine erythrocytes by human serum over a range of serum concentrations. The sera tested
included heat-inactivated (HI) NHS, MBL-/-, NHS +anti-MASP-2 antibody and NHS
control, demonstrating that inhibiting MASP-2 inhibits complement-mediated lysis of nonsensitized WT mouse erythrocytes, as described in Example 33;
FIGURE 42 graphically illustrates hemolysis (as measured by hemoglobin release of
lysed mouse erythrocytes (CD55/59 -/-) into the supernatant measured by photometry) of
non-coated murine erythrocytes by human serum over a range of serum concentrations. The
sera tested included heat-inactivated (HI) NHS, MBL-/-, NHS +anti-MASP-2 antibody and
NHS control, as described in Example 33;
FIGURE 43 graphically illustrates the percent survival over time (days) after
exposure to 8.0 Gy radiation in control mice and in mice treated with anti-human MASP-2
antibody (mAbH6), as described in Example 34;
FIGURE 44 graphically illustrates the time to onset of microvascular occlusion
following LPS injection in MASP-2 -/- and WT mice, showing the percentage of mice with
thrombus formation measured over 60 minutes, demonstrating that thrombus formation is
detected after 15 minutes in WT mice, with up to 80% of the WT mice demonatrated
thrombus formation at 60 minutes; in contrast, none of the MASP-2 -/- mice showed any
thrombus formation during the 60 minute period (log rank: p=0.0005), as described in
Example 35;
FIGURE 45 graphically illustrates the percent survival of saline treated control mice
(n=5) and anti-MASP-2 antibody treated mice (n=5) in the STX/LPS-induced model of HUS
over time (hours), demonstrating that all of the control mice died by 42 hours, whereas, in
contrast, 100 % of the anti-MASP-2 antibody-treated mice survived throughout the time
course of the experiment, as described in Example 36;
FIGURE 46 graphically illustrates, as a function of time after injury induction, the
percentage of mice with microvascular occlusion in the FITC/Dextran UV model after
treatment with isotype control, or human MASP-2 antibody mAbH6 (10mg/kg) dosed at 16
hours and 1 hour prior to injection of FITC/Dextran, as described in Example 37;
FIGURE 47 graphically illustrates the occlusion time in minutes for mice treated with
the human MASP-2 antibody (mAbH6) and the isotype control antibody, wherein the data
are reported as scatter-dots with mean values (horizontal bars) and standard error bars
(vertical bars). The statistical test used for analysis was the unpaired t test; wherein the
symbol “*” indicates p=0.0129, as described in Example 37; and
FIGURE 48 graphically illustrates the time until occlusion in minutes for wild-type
mice, MASP-2 KO mice, and wild-type mice pre-treated with human MASP-2 antibody
(mAbH6) administered i.p. at 10mg/kg 16 hours before, and again 1 hour prior to the
induction of thrombosis in the FITC-dextran/light induced endothelial cell injury model of
thrombosis with low light intensity (800-1500), as described in Example 37;
FIGURE 49 is a Kaplan-Meier plot showing the percentage of mice with thrombi as a
function of time in FITC-Dextran induced thrombotic microangiopathy in mice treated with
increasing doses of human MASP-2 inhibitory antibody (mAbH6) or an isotype control
antibody, as described in Example 39;
FIGURE 50 graphically illustrates the median time to onset (minutes) of thrombus
formation as a function of mAbH6 dose (*p<0.01 compared to control), as described in
Example 39;
FIGURE 51 is a Kaplan-Merier plot showing the percentage of mice with
microvascular occlusion as a function of time in FITC-Dextran induced thrombotic
microangiopathy in mice treated with imcreasing doses of human MASP-2 inhibitory
antibody (mAbH6) or an isotype control antibody, as described in Example 39; and
FIGURE 52 graphically illustrates the median time to microvascular occlusion as a
function of mAbH6 dose (*p<0.05 compared to control), as described in Example 39.
DESCRIPTION OF THE SEQUENCE LISTING
SEQ ID NO:1 human MAp19 cDNA
SEQ ID NO:2 human MAp19 protein (with leader)
SEQ ID NO:3 human MAp19 protein (mature)
SEQ ID NO:4 human MASP-2 cDNA
SEQ ID NO:5 human MASP-2 protein (with leader)
SEQ ID NO:6 human MASP-2 protein (mature)
SEQ ID NO:7 human MASP-2 gDNA (exons 1-6)
ANTIGENS: (IN REFERENCE TO THE MASP-2 MATURE PROTEIN)
SEQ ID NO:8 CUBI sequence (aa 1-121)
SEQ ID NO:9 CUBEGF sequence (aa 1-166)
SEQ ID NO:10 CUBEGFCUBII (aa 1-293)
SEQ ID NO:11 EGF region (aa 122-166)
SEQ ID NO:12 serine protease domain (aa 429 – 671)
SEQ ID NO:13 serine protease domain inactive (aa 610-625 with Ser618 to
Ala mutation)
SEQ ID NO:14 TPLGPKWPEPVFGRL (CUB1 peptide)
SEQ ID NO:15
TAPPGYRLRLYFTHFDLELSHLCEYDFVKLSSGAKVLATLCGQ
(CUBI peptide)
SEQ ID NO:16 TFRSDYSN (MBL binding region core)
SEQ ID NO:17 FYSLGSSLDITFRSDYSNEKPFTGF (MBL binding region)
SEQ ID NO:18 IDECQVAPG (EGF PEPTIDE)
SEQ ID NO:19 ANMLCAGLESGGKDSCRGDSGGALV (serine protease
binding core)Detailed Description
PEPTIDE INHIBITORS:
SEQ ID NO:20 MBL full length cDNA
SEQ ID NO:21 MBL full length protein
SEQ ID NO:22 OGK-X-GP (consensus binding)
SEQ ID NO:23 OGKLG
SEQ ID NO:24 GLR GLQ GPO GKL GPO G
SEQ ID NO:25 GPO GPO GLR GLQ GPO GKL GPO GPO GPO
SEQ ID NO:26 GKDGRDGTKGEKGEPGQGLRGLQGPOGKLGPOG
SEQ ID NO:27 GAOGSOGEKGAOGPQGPOGPOGKMGPKGEOGDO
(human h-ficolin)
SEQ ID NO:28
GCOGLOGAOGDKGEAGTNGKRGERGPOGPOGKAGPOGPNGA
OGEO (human ficolin p35)
SEQ ID NO:29 LQRALEILPNRVTIKANRPFLVFI (C4 cleavage site)
EXPRESSION INHIBITORS:
SEQ ID NO:30 cDNA of CUBI-EGF domain (nucleotides 22-680 of SEQ ID
NO:4)
SEQ ID NO:31
' CGGGCACACCATGAGGCTGCTGACCCTCCTGGGC 3'
Nucleotides 12-45 of SEQ ID NO:4 including the MASP-2 translation
start site (sense)
SEQ ID NO:32
'GACATTACCTTCCGCTCCGACTCCAACGAGAAG3'
Nucleotides 361-396 of SEQ ID NO:4 encoding a region comprising
the MASP-2 MBL binding site (sense)
SEQ ID NO:33
'AGCAGCCCTGAATACCCACGGCCGTATCCCAAA3'
Nucleotides 610-642 of SEQ ID NO:4 encoding a region comprising
the CUBII domain
CLONING PRIMERS:
SEQ ID NO:34 CGGGATCCATGAGGCTGCTGACCCTC (5' PCR for
CUB)
SEQ ID NO:35 GGAATTCCTAGGCTGCATA (3' PCR FOR CUB)
SEQ ID NO:36 GGAATTCCTACAGGGCGCT (3' PCR FOR CUBIEGF)
SEQ ID NO:37 GGAATTCCTAGTAGTGGAT (3' PCR FOR
CUBIEGFCUBII)
SEQ ID NOS:38-47 are cloning primers for humanized antibody
SEQ ID NO:48 is 9 aa peptide bond
EXPRESSION VECTOR:
SEQ ID NO:49 is the MASP-2 minigene insert
SEQ ID NO: 50 is the murine MASP-2 cDNA
SEQ ID NO: 51 is the murine MASP-2 protein (w/leader)
SEQ ID NO: 52 is the mature murine MASP-2 protein
SEQ ID NO: 53 the rat MASP-2 cDNA
SEQ ID NO: 54 is the rat MASP-2 protein (w/ leader)
SEQ ID NO: 55 is the mature rat MASP-2 protein
SEQ ID NO: 56-59 are the oligonucleotides for site-directed mutagenesis of
human MASP-2 used to generate human MASP-2A
SEQ ID NO: 60-63 are the oligonucleotides for site-directed mutagenesis of
murine MASP-2 used to generate murine MASP-2A
SEQ ID NO: 64-65 are the oligonucleotides for site-directed mutagenesis of
rat MASP-2 used to generate rat MASP-2A
DETAILED DESCRIPTION
The present invention is based upon the surprising discovery by the present inventors
that it is possible to inhibit the lectin mediated MASP-2 pathway while leaving the classical
pathway intact. The present invention also describes the use of MASP-2 as a therapeutic
target for inhibiting cellular injury associated with lectin-mediated complement pathway
activation while leaving the classical (C1q-dependent) pathway component of the immune
system intact.
I. DEFINITIONS
Unless specifically defined herein, all terms used herein have the same meaning as
would be understood by those of ordinary skill in the art of the present invention. The
following definitions are provided in order to provide clarity with respect to the terms as they
are used in the specification and claims to describe the present invention.
As used herein, the term “MASPdependent complement activation” comprises
MASP dependent activation of the lectin pathway, which occurs under physiological
conditions (i.e., in the presence of Ca++) leading to the formation of the lectin pathway C3
convertase C4b2a and upon accumulation of the C3 cleavage product C3b subsequently to
the C5 convertase C4b2a(C3b)n, which has been determined to primarily cause opsonization.
As used herein, the term "alternative pathway" refers to complement activation that is
triggered, for example, by zymosan from fungal and yeast cell walls, lipopolysaccharide
(LPS) from Gram negative outer membranes, and rabbit erythrocytes, as well as from many
pure polysaccharides, rabbit erythrocytes, viruses, bacteria, animal tumor cells, parasites and
damaged cells, and which has traditionally been thought to arise from spontaneous
proteolytic generation of C3b from complement factor C3.
As used herein, the term "lectin pathway" refers to complement activation that occurs
via the specific binding of serum and non-serum carbohydrate-binding proteins including
mannan-binding lectin (MBL), CL-11 and the ficolins (H-ficolin, M-ficolin, or L-ficolin).
As used herein, the term "classical pathway" refers to complement activation that is
triggered by antibody bound to a foreign particle and requires binding of the recognition
molecule C1q.
As used herein, the term "MASP-2 inhibitory agent" refers to any agent that binds to
or directly interacts with MASP-2 and effectively inhibits MASPdependent complement
activation, including anti-MASP-2 antibodies and MASP-2 binding fragments thereof,
natural and synthetic peptides, small molecules, soluble MASP-2 receptors, expression
inhibitors and isolated natural inhibitors, and also encompasses peptides that compete with
MASP-2 for binding to another recognition molecule (e.g., MBL, H-ficolin, M-ficolin, or
L-ficolin) in the lectin pathway, but does not encompass antibodies that bind to such other
recognition molecules. MASP-2 inhibitory agents useful in the method of the invention may
reduce MASPdependent complement activation by greater than 20%, such as greater than
50%, such as greater than 90%. In one embodiment, the MASP-2 inhibitory agent reduces
MASPdependent complement activation by greater than 90% (i.e., resulting in MASP-2
complement activation of only 10% or less).
As used herein, the term "antibody" encompasses antibodies and antibody fragments
thereof, derived from any antibody-producing mammal (e.g., mouse, rat, rabbit, and primate
including human), or from a hybridoma, phage selection, recombinant expression or
transgenic animals (or other methods of producing antibodies or antibody fragments”), that
specifically bind to a target polypeptide, such as, for example, MASP-2, polypeptides or
portions thereof. It is not intended that the term “antibody” limited as regards to the source
of the antibody or the manner in which it is made (e.g., by hybridoma, phage selection,
recombinant expression, transgenic animal, peptide synthesis, etc). Exemplary antibodies
include polyclonal, monoclonal and recombinant antibodies; pan-specific, multispecific
antibodies (e.g., bispecific antibodies, trispecific antibodies); humanized antibodies; murine
antibodies; chimeric, mouse-human, mouse-primate, primate-human monoclonal antibodies;
and anti-idiotype antibodies, and may be any intact antibody or fragment thereof. As used
herein, the term “antibody” encompasses not only intact polyclonal or monoclonal
antibodies, but also fragments thereof (such as dAb, Fab, Fab', F(ab')2, Fv), single chain
(ScFv), synthetic variants thereof, naturally occurring variants, fusion proteins comprising an
antibody portion with an antigen-binding fragment of the required specificity, humanized
antibodies, chimeric antibodies, and any other modified configuration of the immunoglobulin
molecule that comprises an antigen-binding site or fragment (epitope recognition site) of the
required specificity.
A “monoclonal antibody" refers to a homogeneous antibody population wherein the
monoclonal antibody is comprised of amino acids (naturally occurring and non-naturally
occurring) that are involved in the selective binding of an epitope. Monoclonal antibodies
are highly specific for the target antigen. The term "monoclonal antibody" encompasses not
only intact monoclonal antibodies and full-length monoclonal antibodies, but also fragments
thereof (such as Fab, Fab', F(ab')2, Fv), single chain (ScFv), variants thereof, fusion proteins
comprising an antigen-binding portion, humanized monoclonal antibodies, chimeric
monoclonal antibodies, and any other modified configuration of the immunoglobulin
molecule that comprises an antigen-binding fragment (epitope recognition site) of the
required specificity and the ability to bind to an epitope. It is not intended to be limited as
regards the source of the antibody or the manner in which it is made (e.g., by hybridoma,
phage selection, recombinant expression, transgenic animals, etc.). The term includes whole
immunoglobulins as well as the fragments etc. described above under the definition of
"antibody".
As used herein, the term "antibody fragment" refers to a portion derived from or
related to a full-length antibody, such as, for example, an anti-MASP-2 antibody, generally
including the antigen binding or variable region thereof. Illustrative examples of antibody
fragments include Fab, Fab', F(ab)2, F(ab')2 and Fv fragments, scFv fragments, diabodies,
linear antibodies, single-chain antibody molecules and multispecific antibodies formed from
antibody fragments.
As used herein, a "single-chain Fv" or "scFv" antibody fragment comprises the VH
and VL domains of an antibody, wherein these domains are present in a single polypeptide
chain. Generally, the Fv polypeptide further comprises a polypeptide linker between the VH
and VL domains, which enables the scFv to form the desired structure for antigen binding.
As used herein, a "chimeric antibody" is a recombinant protein that contains the
variable domains and complementarity-determining regions derived from a non-human
species (e.g., rodent) antibody, while the remainder of the antibody molecule is derived from
a human antibody.
As used herein, a "humanized antibody" is a chimeric antibody that comprises a
minimal sequence that conforms to specific complementarity-determining regions derived
from non-human immunoglobulin that is transplanted into a human antibody framework.
Humanized antibodies are typically recombinant proteins in which only the antibody
complementarity-determining regions are of non-human origin.
As used herein, the term "mannan-binding lectin" ("MBL") is equivalent to
mannan-binding protein ("MBP").
As used herein, the "membrane attack complex" ("MAC") refers to a complex of the
terminal five complement components (C5b combined with C6, C7, C8 and C-9) that inserts
into and disrupts membranes (also referred to as C5b-9).
As used herein, "a subject" includes all mammals, including without limitation
humans, non-human primates, dogs, cats, horses, sheep, goats, cows, rabbits, pigs and
rodents.
As used herein, the amino acid residues are abbreviated as follows: alanine (Ala;A),
asparagine (Asn;N), aspartic acid (Asp;D), arginine (Arg;R), cysteine (Cys;C), glutamic acid
(Glu;E), glutamine (Gln;Q), glycine (Gly;G), histidine (His;H), isoleucine (Ile;I), leucine
(Leu;L), lysine (Lys;K), methionine (Met;M), phenylalanine (Phe;F), proline (Pro;P), serine
(Ser;S), threonine (Thr;T), tryptophan (Trp;W), tyrosine (Tyr;Y), and valine (Val;V).
In the broadest sense, the naturally occurring amino acids can be divided into groups
based upon the chemical characteristic of the side chain of the respective amino acids. By
"hydrophobic" amino acid is meant either Ile, Leu, Met, Phe, Trp, Tyr, Val, Ala, Cys or Pro.
By "hydrophilic" amino acid is meant either Gly, Asn, Gln, Ser, Thr, Asp, Glu, Lys, Arg or
His. This grouping of amino acids can be further subclassed as follows. By "uncharged
hydrophilic" amino acid is meant either Ser, Thr, Asn or Gln. By "acidic" amino acid is
meant either Glu or Asp. By "basic" amino acid is meant either Lys, Arg or His.
As used herein the term "conservative amino acid substitution" is illustrated by a
substitution among amino acids within each of the following groups: (1) glycine, alanine,
valine, leucine, and isoleucine, (2) phenylalanine, tyrosine, and tryptophan, (3) serine and
threonine, (4) aspartate and glutamate, (5) glutamine and asparagine, and (6) lysine, arginine
and histidine.
The term "oligonucleotide" as used herein refers to an oligomer or polymer of
ribonucleic acid (RNA) or deoxyribonucleic acid (DNA) or mimetics thereof. This term also
covers those oligonucleobases composed of naturally-occurring nucleotides, sugars and
covalent internucleoside (backbone) linkages as well as oligonucleotides having
non-naturally-occurring modifications.
As used herein, an "epitope" refers to the site on a protein (e.g., a human MASP-2
protein) that is bound by an antibody. "Overlapping epitopes" include at least one (e.g., two,
three, four, five, or six) common amino acid residue(s), including linear and non-linear
epitopes.
As used herein, the terms "polypeptide," "peptide," and "protein" are used
interchangeably and mean any peptide-linked chain of amino acids, regardless of length or
post-translational modification. The MASP-2 protein described herein can contain or be
wild-type proteins or can be variants that have not more than 50 (e.g., not more than one,
two, three, four, five, six, seven, eight, nine, ten, 12, 15, 20, 25, 30, 35, 40, or 50)
conservative amino acid substitutions. Conservative substitutions typically include
substitutions within the following groups: glycine and alanine; valine, isoleucine, and
leucine; aspartic acid and glutamic acid; asparagine, glutamine, serine and threonine; lysine,
histidine and arginine; and phenylalanine and tyrosine.
In some embodiments, the human MASP-2 protein can have an amino acid sequence
that is, or is greater than, 70 (e.g., 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86,
87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, or 100) % identical to the human MASP-2
protein having the amino acid sequence set forth in SEQ ID NO: 5.
In some embodiments, peptide fragments can be at least 6 (e.g., at least 7, 8, 9, 10,
11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35,
36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95,
100, 110, 120, 130, 140, 150, 160, 170, 180, 190, 200, 250, 300, 350, 400, 450, 500, or 600
or more) amino acid residues in length (e.g., at least 6 contiguous amino acid residues of
SEQ ID NO: 5). In some embodiments, an antigenic peptide fragment of a human MASP-2
protein is fewer than 500 (e.g., fewer than 450, 400, 350, 325, 300, 275, 250, 225, 200, 190,
180, 170, 160, 150, 140, 130, 120, 110, 100, 95, 90, 85, 80, 75, 70, 65, 60, 55, 50, 49, 48, 47,
46, 45, 44, 43, 42, 41, 40, 39, 38, 37, 36, 35, 34, 33, 32, 31, 30, 29, 28, 27, 26, 25, 24, 23, 22,
21, 20, 19, 18, 17, 16, 15, 14, 13, 12, 11, 10, 9, 8, 7, or 6) amino acid residues in length (e.g.,
fewer than 500 contiguous amino acid residues in any one of SEQ ID NOS: 5).
Percent (%) amino acid sequence identity is defined as the percentage of amino acids
in a candidate sequence that are identical to the amino acids in a reference sequence, after
aligning the sequences and introducing gaps, if necessary, to achieve the maximum percent
sequence identity. Alignment for purposes of determining percent sequence identity can be
achieved in various ways that are within the skill in the art, for instance, using publicly
available computer software such as BLAST, BLAST-2, ALIGN, ALIGN-2 or Megalign
(DNASTAR) software. Appropriate parameters for measuring alignment, including any
algorithms needed to achieve maximal alignment over the full-length of the sequences being
compared can be determined by known methods.
II. Overview of the Invention
Lectins (MBL, M-ficolin, H-ficolin, L-ficolin and CL-11) are the specific recognition
molecules that trigger the innate complement system and the system includes the lectin
initiation pathway and the associated terminal pathway amplification loop that amplifies
lectin-initiated activation of terminal complement effector molecules. C1q is the specific
recognition molecule that triggers the acquired complement system and the system includes
the classical initiation pathway and associated terminal pathway amplification loop that
amplifies C1q-initiated activation of terminal complement effector molecules. We refer to
these two major complement activation systems as the lectin-dependent complement system
and the C1q-dependent complement system, respectively.
In addition to its essential role in immune defense, the complement system
contributes to tissue damage in many clinical conditions. Thus, there is a pressing need to
develop therapeutically effective complement inhibitors to prevent these adverse effects.
With the recognition that it is possible to inhibit the lectin mediated MASP-2 pathway while
leaving the classical pathway intact comes the realization that it would be highly desirable to
specifically inhibit only the complement activation system causing a particular pathology
without completely shutting down the immune defense capabilities of complement. For
example, in disease states in which complement activation is mediated predominantly by the
lectin-dependent complement system, it would be advantageous to specifically inhibit only
this system. This would leave the C1q-dependent complement activation system intact to
handle immune complex processing and to aid in host defense against infection.
The preferred protein component to target in the development of therapeutic agents to
specifically inhibit the lectin-dependent complement system is MASP-2. Of all the known
protein components of the lectin-dependent complement system (MBL, H-ficolin, M-ficolin,
L-ficolin, MASP-2, C2-C9, Factor B, Factor D, and properdin), only MASP-2 is both unique
to the lectin-dependent complement system and required for the system to function. The
lectins (MBL, H-ficolin, M-ficolin,L-ficolin and CL-11) are also unique components in the
lectin-dependent complement system. However, loss of any one of the lectin components
would not necessarily inhibit activation of the system due to lectin redundancy. It would be
necessary to inhibit all five lectins in order to guarantee inhibition of the lectin-dependent
complement activation system. Furthermore, since MBL and the ficolins are also known to
have opsonic activity independent of complement, inhibition of lectin function would result
in the loss of this beneficial host defense mechanism against infection. In contrast, this
complement-independent lectin opsonic activity would remain intact if MASP-2 was the
inhibitory target. An added benefit of MASP-2 as the therapeutic target to inhibit the
lectin-dependent complement activation system is that the plasma concentration of MASP-2
is among the lowest of any complement protein (≈ 500 ng/ml); therefore, correspondingly
low concentrations of high-affinity inhibitors of MASP-2 may be sufficient to obtain full
inhibition (Moller-Kristensen, M., et al., J. Immunol Methods 282:159-167, 2003).
III. ROLE OF MASP-2 IN VARIOUS DISEASES AND CONDITIONS AND
THERAPEUTIC METHODS USING MASP-2 INHIBITORY AGENTS
RENAL CONDITIONS
Activation of the complement system has been implicated in the pathogenesis of a
wide variety of renal diseases; including, mesangioproliferative glomerulonephritis
(IgA-nephropathy, Berger's disease) (Endo, M., et al., Clin. Nephrology 55:185-191, 2001),
membranous glomerulonephritis (Kerjashki, D., Arch B Cell Pathol. 58:253-71, 1990;
Brenchley, P.E., et al., Kidney Int., 41:933-7, 1992; Salant, D.J., et al., Kidney Int. 35:976-84,
1989), membranoproliferative glomerulonephritis (mesangiocapillary glomerulonephritis)
(Bartlow, B.G., et al., Kidney Int. 15:294-300, 1979; Meri, S., et al., J. Exp.
Med. 175:939-50, 1992), acute postinfectious glomerulonephritis (poststreptococcal
glomerulonephritis), cryoglobulinemic glomerulonephritis (Ohsawa, I., et al., Clin
Immunol. 101:59-66, 2001), lupus nephritis (Gatenby, P.A., Autoimmunity 11:61-6, 1991),
and Henoch-Schonlein purpura nephritis (Endo, M., et al., Am. J. Kidney Dis. 35:401-407,
2000). The involvement of complement in renal disease has been appreciated for several
decades but there is still a major discussion on its exact role in the onset, the development
and the resolution phase of renal disease. Under normal conditions the contribution of
complement is beneficial to the host, but inappropriate activation and deposition of
complement may contribute to tissue damage.
There is substantial evidence that glomerulonephritis, inflammation of the glomeruli,
is often initiated by deposition of immune complexes onto glomerular or tubular structures
which then triggers complement activation, inflammation and tissue damage. Kahn and
Sinniah demonstrated increased deposition of C5b-9 in tubular basement membranes in
biopsies taken from patients with various forms of glomerulonephritis (Kahn, T.N., et al.,
Histopath. 26:351-6, 1995). In a study of patients with IgA nephrology (Alexopoulos,
A., et al., Nephrol. Dial. Transplant 10:1166-1172, 1995), C5b-9 deposition in the tubular
epithelial/basement membrane structures correlated with plasma creatinine levels. Another
study of membranous nephropathy demonstrated a relationship between clinical outcome and
urinary sC5b-9 levels (Kon, S.P., et al., Kidney Int. 48:1953-58, 1995). Elevated sC5b-9
levels were correlated positively with poor prognosis. Lehto et al., measured elevated levels
of CD59, a complement regulatory factor that inhibits the membrane attack complex in
plasma membranes, as well as C5b-9 in urine from patients with membranous
glomerulonephritis (Lehto, T., et al., Kidney Int. 47:1403-11, 1995). Histopathological
analysis of biopsy samples taken from these same patients demonstrated deposition of C3
and C9 proteins in the glomeruli, whereas expression of CD59 in these tissues was
diminished compared to that of normal kidney tissue. These various studies suggest that
ongoing complement-mediated glomerulonephritis results in urinary excretion of
complement proteins that correlate with the degree of tissue damage and disease prognosis.
Inhibition of complement activation in various animal models of glomerulonephritis
has also demonstrated the importance of complement activation in the etiology of the
disease. In a model of membranoproliferative glomerulonephritis (MPGN), infusion of
anti-Thy1 antiserum in C6-deficient rats (that cannot form C5b-9) resulted in 90% less
glomerular cellular proliferation, 80% reduction in platelet and macrophage infiltration,
diminished collagen type IV synthesis (a marker for mesangial matrix expansion), and 50%
less proteinuria than in C6+ normal rats (Brandt, J., et al., Kidney Int. 49:335-343, 1996).
These results implicate C5b-9 as a major mediator of tissue damage by complement in this
rat anti-thymocyte serum model. In another model of glomerulonephritis, infusion of graded
dosages of rabbit anti-rat glomerular basement membrane produced a dose-dependent influx
of polymorphonuclear leukocytes (PMN) that was attenuated by prior treatment with cobra
venom factor (to consume complement) (Scandrett, A.L., et al., Am. J.
Physiol. 268:F256-F265, 1995). Cobra venom factor-treated rats also showed diminished
histopathology, decreased long-term proteinuria, and lower creatinine levels than control
rats. Employing three models of GN in rats (anti-thymocyte serum, Con A anti-Con A, and
passive Heymann nephritis), Couser et al., demonstrated the potential therapeutic efficacy of
approaches to inhibit complement by using the recombinant sCR1 protein (Couser,
W.G., et al., J. Am. Soc. Nephrol. 5:1888-94, 1995). Rats treated with sCR1 showed
significantly diminished PMN, platelet and macrophage influx, decreased mesangiolysis, and
proteinuria versus control rats. Further evidence for the importance of complement
activation in glomerulonephritis has been provided by the use of an anti-C5 MoAb in the
NZB/W F1 mouse model. The anti-C5 MoAb inhibits cleavage of C5, thus blocking
generation of C5a and C5b-9. Continuous therapy with anti-C5 MoAb for 6 months resulted
in significant amelioration of the course of glomerulonephritis. A humanized anti-C5 MoAb
monoclonal antibody (5G1.1) that prevents the cleavage of human complement component
C5 into its pro-inflammatory components is under development by Alexion Pharmaceuticals,
Inc., New Haven, Connecticut, as a potential treatment for glomerulonephritis.
Direct evidence for a pathological role of complement in renal injury is provided by
studies of patients with genetic deficiencies in specific complement components. A number
of reports have documented an association of renal disease with deficiencies of complement
regulatory factor H (Ault, B.H., Nephrol. 14:1045-1053, 2000; Levy, M., et al., Kidney Int.
:949-56, 1986; Pickering, M.C., et al., Nat. Genet. 31:424-8, 2002). Factor H deficiency
results in low plasma levels of factor B and C3 and in consumption of C5b-9. Both atypical
membranoproliferative glomerulonephritis (MPGN) and idiopathic hemolytic uremic
syndrome (HUS) are associated with factor H deficiency. Factor H deficient pigs (Jansen,
J.H., et al., Kidney Int. 53:331-49, 1998) and factor H knockout mice (Pickering, M.C., 2002)
display MPGN-like symptoms, confirming the importance of factor H in complement
regulation. Deficiencies of other complement components are associated with renal disease,
secondary to the development of systemic lupus erythematosus (SLE) (Walport, M.J.,
Davies, et al., Ann. N.Y. Acad. Sci. 815:267-81, 1997). Deficiency for C1q, C4 and C2
predispose strongly to the development of SLE via mechanisms relating to defective
clearance of immune complexes and apoptotic material. In many of these SLE patients lupus
nephritis occurs, characterized by the deposition of immune complexes throughout the
glomerulus.
Further evidence linking complement activation and renal disease has been provided
by the identification in patients of autoantibodies directed against complement components,
some of which have been directly related to renal disease (Trouw, L.A., et al., Mol.
Immunol. 38:199-206, 2001). A number of these autoantibodies show such a high degree of
correlation with renal disease that the term nephritic factor (NeF) was introduced to indicate
this activity. In clinical studies, about 50% of the patients positive for nephritic factors
developed MPGN (Spitzer, R.E., et al., Clin. Immunol. Immunopathol. 64:177-83, 1992).
C3NeF is an autoantibody directed against the alternative pathway C3 convertase (C3bBb)
and it stabilizes this convertase, thereby promoting alternative pathway activation (Daha,
M.R., et al., J. Immunol. 116:1-7, 1976). Likewise, autoantibody with a specificity for the
classical pathway C3 convertase (C4b2a), called C4NeF, stabilizes this convertase and
thereby promotes classical pathway activation (Daha, M.R. et al., J.
Immunol. 125:2051-2054, 1980; Halbwachs, L., et al., J. Clin. Invest. 65:1249-56, 1980).
Anti-C1q autoantibodies have been described to be related to nephritis in SLE patients
(Hovath, L., et al., Clin. Exp. Rheumatol. 19:667-72, 2001; Siegert, C., et al., J.
Rheumatol. 18:230-34, 1991; Siegert, C., et al., Clin. Exp. Rheumatol. 10:19-23, 1992), and a
rise in the titer of these anti-C1q autoantibodies was reported to predict a flare of nephritis
(Coremans, I.E., et al., Am. J. Kidney Dis. 26:595-601, 1995). Immune deposits eluted from
postmortem kidneys of SLE patients revealed the accumulation of these anti-C1q
autoantibodies (Mannick, M., et al., Arthritis Rheumatol. 40:1504-11, 1997). All these facts
point to a pathological role for these autoantibodies. However, not all patients with anti-C1q
autoantibodies develop renal disease and also some healthy individuals have low titer
anti-C1q autoantibodies (Siegert, C.E., et al., Clin. Immunol. Immunopathol. 67:204-9,
1993).
In addition to the alternative and classical pathways of complement activation, the
lectin pathway may also have an important pathological role in renal disease. Elevated levels
of MBL, MBL-associated serine protease and complement activation products have been
detected by immunohistochemical techniques on renal biopsy material obtained from patients
diagnosed with several different renal diseases, including Henoch-Schonlein purpura
nephritis (Endo, M., et al., Am. J. Kidney Dis. 35:401-407, 2000), cryoglobulinemic
glomerulonephritis (Ohsawa, I., et al., Clin. Immunol. 101:59-66, 2001) and IgA neuropathy
(Endo, M., et al., Clin. Nephrology 55:185-191, 2001). Therefore, despite the fact that an
association between complement and renal diseases has been known for several decades,
data on how complement exactly influences these renal diseases is far from complete.
One aspect of the invention is thus directed to the treatment of renal conditions
including but not limited to mesangioproliferative glomerulonephritis, membranous
glomerulonephritis, membranoproliferative glomerulonephritis (mesangiocapillary
glomerulonephritis), acute postinfectious glomerulonephritis (poststreptococcal
glomerulonephritis), cryoglobulinemic glomerulonephritis, lupus nephritis,
Henoch-Schonlein purpura nephritis or IgA nephropathy, by administering a composition
comprising a therapeutically effective amount of a MASP-2 inhibitory agent in a
pharmaceutical carrier to a subject suffering from such a disorder. The MASP-2 inhibitory
agent may be administered to the subject systemically, such as by intra-arterial, intravenous,
intramuscular, subcutaneous or other parenteral administration, or potentially by oral
administration for non-peptidergic agents. The MASP-2 inhibitory agent may be
administered periodically over an extended period of time for treatment or control of a
chronic condition, or may be by single or repeated administration in the period before, during
or following acute trauma or injury.
BLOOD DISORDERS
Sepsis is caused by an overwhelming reaction of the patient to invading
microorganisms. A major function of the complement system is to orchestrate the
inflammatory response to invading bacteria and other pathogens. Consistent with this
physiological role, complement activation has been shown in numerous studies to have a
major role in the pathogenesis of sepsis (Bone, R.C., Annals. Internal. Med. 115:457-469,
1991). The definition of the clinical manifestations of sepsis is ever evolving. Sepsis is
usually defined as the systemic host response to an infection. However, on many occasions,
no clinical evidence for infection (e.g., positive bacterial blood cultures) is found in patients
with septic symptoms. This discrepancy was first taken into account at a Consensus
Conference in 1992 when the term "systemic inflammatory response syndrome" (SIRS) was
established, and for which no definable presence of bacterial infection was required (Bone,
R.C., et al., Crit. Care Med. 20:724-726, 1992). There is now general agreement that sepsis
and SIRS are accompanied by the inability to regulate the inflammatory response. For the
purposes of this brief review, we will consider the clinical definition of sepsis to also include
severe sepsis, septic shock, and SIRS.
The predominant source of infection in septic patients before the late 1980s was
Gram-negative bacteria. Lipopolysaccharide (LPS), the main component of the
Gram-negative bacterial cell wall, was known to stimulate release of inflammatory mediators
from various cell types and induce acute infectious symptoms when injected into animals
(Haeney, M.R., et al., Antimicrobial Chemotherapy 41(Suppl. A):41-6, 1998). Interestingly,
the spectrum of responsible microorganisms appears to have shifted from predominantly
Gram-negative bacteria in the late 1970s and 1980s to predominantly Gram-positive bacteria
at present, for reasons that are currently unclear (Martin, G.S., et al., N. Eng. J.
Med. 348:1546-54, 2003).
Many studies have shown the importance of complement activation in mediating
inflammation and contributing to the features of shock, particularly septic and hemorrhagic
shock. Both Gram-negative and Gram-positive organisms commonly precipitate septic
shock. LPS is a potent activator of complement, predominantly via the alternative pathway,
although classical pathway activation mediated by antibodies also occurs (Fearon, D.T.,
et al., N. Engl. J. Med. 292:937-400, 1975). The major components of the Gram-positive cell
wall are peptidoglycan and lipoteichoic acid, and both components are potent activators of
the alternative complement pathway, although in the presence of specific antibodies they can
also activate the classical complement pathway (Joiner, K.A., et al., Ann. Rev.
Immunol. 2:461-2, 1984).
The complement system was initially implicated in the pathogenesis of sepsis when it
was noted by researchers that anaphylatoxins C3a and C5a mediate a variety of inflammatory
reactions that might also occur during sepsis. These anaphylatoxins evoke vasodilation and
an increase in microvascular permeability, events that play a central role in septic shock
(Schumacher, W.A., et al., Agents Actions 34:345-349, 1991). In addition, the
anaphylatoxins induce bronchospasm, histamine release from mast cells, and aggregation of
platelets. Moreover, they exert numerous effects on granulocytes, such as chemotaxis,
aggregation, adhesion, release of lysosomal enzymes, generation of toxic super oxide anion
and formation of leukotrienes (Shin, H.S., et al., Science 162:361-363, 1968; Vogt, W.,
Complement 3:177-86, 1986). These biologic effects are thought to play a role in
development of complications of sepsis such as shock or acute respiratory distress syndrome
(ARDS) (Hammerschmidt, D.E., et al., Lancet 1:947-949, 1980; Slotman, G.T., et al.,
Surgery 99:744-50, 1986). Furthermore, elevated levels of the anaphylatoxin C3a is
associated with a fatal outcome in sepsis (Hack, C.E., et al., Am. J. Med. 86:20-26, 1989). In
some animal models of shock, certain complement-deficient strains (e.g., C5-deficient ones)
are more resistant to the effects of LPS infusions (Hseuh, W., et al., Immunol. 70:309-14,
1990).
Blockade of C5a generation with antibodies during the onset of sepsis in rodents has
been shown to greatly improve survival (Czermak, B.J., et al., Nat. Med. 5:788-792, 1999).
Similar findings were made when the C5a receptor (C5aR) was blocked, either with
antibodies or with a small molecular inhibitor (Huber-Lang, M.S., et al., FASEB
J. 16:1567-74, 2002; Riedemann, N.C., et al., J. Clin. Invest. 110:101-8, 2002). Earlier
experimental studies in monkeys have suggested that antibody blockade of C5a attenuated
E. coli-induced septic shock and adult respiratory distress syndrome (Hangen, D.H., et al., J.
Surg. Res. 46:195-9, 1989; Stevens, J.H., et al., J. Clin. Invest. 77:1812-16, 1986). In
humans with sepsis, C5a was elevated and associated with significantly reduced survival
rates together with multiorgan failure, when compared with that in less severely septic
patients and survivors (Nakae, H., et al., Res. Commun. Chem. Pathol.
Pharmacol. 84:189-95, 1994; Nakae, et al., Surg. Today 26:225-29, 1996; Bengtson, A.,
et al., Arch. Surg. 123:645-649, 1988). The mechanisms by which C5a exerts its harmful
effects during sepsis are yet to be investigated in greater detail, but recent data suggest the
generation of C5a during sepsis significantly compromises innate immune functions of blood
neutrophils (Huber-Lang, M.S., et al., J. Immunol. 169:3223-31, 2002), their ability to
express a respiratory burst, and their ability to generate cytokines (Riedemann, N.C., et al.,
Immunity 19:193-202, 2003). In addition, C5a generation during sepsis appears to have
procoagulant effects (Laudes, I.J., et al., Am. J. Pathol. 160:1867-75, 2002). The
complement-modulating protein CI INH has also shown efficacy in animal models of sepsis
and ARDS (Dickneite, G., Behring Ins. Mitt. 93:299-305, 1993).
The lectin pathway may also have a role in pathogenesis of sepsis. MBL has been
shown to bind to a range of clinically important microorganisms including both
Gram-negative and Gram-positive bacteria, and to activate the lectin pathway (Neth, O.,
et al., Infect. Immun. 68:688, 2000). Lipoteichoic acid (LTA) is increasingly regarded as the
Gram-positive counterpart of LPS. It is a potent immunostimulant that induces cytokine
release from mononuclear phagocytes and whole blood (Morath, S., et al., J. Exp.
Med. 195:1635, 2002; Morath, S., et al., Infect. Immun. 70:938, 2002). Recently it was
demonstrated that L-ficolin specifically binds to LTA isolated from numerous Gram-positive
bacteria species, including Staphylococcus aureus, and activates the lectin pathway (Lynch,
N.J., et al., J. Immunol. 172:1198-02, 2004). MBL also has been shown to bind to LTA from
Enterococcus spp in which the polyglycerophosphate chain is substituted with glycosyl
groups), but not to LTA from nine other species including S. aureus (Polotsky, V.Y., et al.,
Infect. Immun. 64:380, 1996).
An aspect of the invention thus provides a method for treating sepsis or a condition
resulting from sepsis, by administering a composition comprising a therapeutically effective
amount of a MASP-2 inhibitory agent in a pharmaceutical carrier to a subject suffering from
sepsis or a condition resulting from sepsis including without limitation severe sepsis, septic
shock, acute respiratory distress syndrome resulting from sepsis, and systemic inflammatory
response syndrome. Related methods are provided for the treatment of other blood disorders,
including hemorrhagic shock, hemolytic anemia, autoimmune thrombotic thrombocytopenic
purpura (TTP), hemolytic uremic syndrome (HUS), atypical hemolytic uremic syndrome
(aHUS), or other marrow/blood destructive conditions, by administering a composition
comprising a therapeutically effective amount of a MASP-2 inhibitory agent in a
pharmaceutical carrier to a subject suffering from such a condition. The MASP-2 inhibitory
agent is administered to the subject systemically, such as by intra-arterial, intravenous,
intramuscular, inhalational (particularly in the case of ARDS), subcutaneous or other
parenteral administration, or potentially by oral administration for non-peptidergic agents.
The MASP-2 inhibitory agent composition may be combined with one or more additional
therapeutic agents to combat the sequelae of sepsis and/or shock. For advanced sepsis or
shock or a distress condition resulting therefrom, the MASP-2 inhibitory composition may
suitably be administered in a fast-acting dosage form, such as by intravenous or intra-arterial
delivery of a bolus of a solution containing the MASP-2 inhibitory agent composition.
Repeated administration may be carried out as determined by a physician until the condition
has been resolved.
THE ROLE OF MASP-2 IN PAROXYSMAL NOCTURNAL HEMOGLOBINURINA
AND THERAPEUTIC METHODS USING MASP-2 INHIBITORY AGENTS
Overview of PNH
Paroxysmal nocturnal hemoglobinuria (PNH), sometimes also referred to as
Marchiafava-Micheli syndrome, is an acquired, potentially life-threatening disease of the
blood. PNH may develop on its own, referred to as "primary PNH" or in the context of other
bone marrow disorders such as aplastic anemia, referred to as "secondary PNH." The
majority of cases are primary PNH. PNH is characterized by complement-induced
destruction of red blood cells (hemolysis), low red blood cell counts (anemia), thrombosis
and bone marrow failure. Laboratory findings in PNH show changes consistent with
intravascular hemolytic anemia: low hemoglobin, raised lactate dehydrogenase, raised
reticulocyte counts (immature red cells released by the bone marrow to replace the destroyed
cells), raised bilirubin (a breakdown product of hemoglobin), in the absence of autoreactive
RBC-binding antibodies as a possible cause.
The hallmark of PNH is the chronic complement-mediated hemolysis caused by the
unregulated activation of terminal complement components, including the membrane attack
complex, on the surface of circulating RBCs. PNH RBCs are subject to uncontrolled
complement activation and hemolysis due to the absence of the complement regulators CD55
and CD59 on their surface (Lindorfer, M.A., et al., Blood 115(11):2283-91 (2010), Risitano,
et al., Mini-Reviews in Medicinal Chemistry, 11:528-535 (2011)). CD55 and CD59 are
abundantly expressed on normal RBCs and control complement activation. CD55 acts as a
negative regulator of the alternative pathway, inhibiting the assembly of the alternative
pathway C3 convertase (C3bBb) complex and accelerating the decay of preformed
convertase, thus blocking the formation of the membrane attack complex (MAC). CD59
inhibits the complement membrane attack complex directly by binding the C5b678 complex
and preventing C9 from binding and polymerizing.
While hemolysis and anemia are the dominant clinical features of PNH, the disease is
a complex hematologic disorder that further includes thrombosis and bone marrow failure as
part of the clinical findings (Risitano et al, Mini Reviews in Med Chem11:528-535 (2011)).
At the molecular level, PNH is caused by the abnormal clonal expansion of hematopoietic
stem cells lacking a functional PIG A gene. PIG A is an X-linked gene encoding a glycosyl-
phosphatidyl inositol (GPI) transferase required for the stable surface expression of GPIanchored class A glycoproteins, including CD55 and CD59. For reasons that are presently
under investigation, hematopoietic stem cells with a dysfunctional PIG A gene that arise as
the result of spontaneous somatic mutations can undergo clonal expansion to the point where
their progeny constitute a significant portion of the peripheral hematopoietic cell pool.
While both erythrocyte and lymphocyte progeny of the mutant stem cell clone lack CD55
and CD59, only the RBCs undergo overt lysis after they enter the circulation.
Current treatment for PNH includes blood transfusion for anemia, anticoagulation for
thrombosis and the use of the monoclonal antibody eculizumab (Soliris®), which protects
blood cells against immune destruction by inhibiting the complement system (Hillmen P. et
al., N. Engl. J. Med. 350(6):552-559 (2004)). Eculizumab (Soliris®) is a humanized
monoclonal antibody that targets the complement component C5, blocking its cleavage by
C5 convertases, thereby preventing the production of C5a and the assembly of the MAC.
Treatment of PNH patients with eculizumab has resulted in a reduction of intravascular
hemolysis, as measured by lactate dehydrogenase (LDH), leading to hemoglobin stabilization
and transfusion independence in about half of the patients (Risitano et al, Mini-Reviews in
Medicinal Chemistry, 11(6) (2011)). While nearly all patients undergoing therapy with
eculizumab achieve normal or almost normal LDH levels (due to control of intravascular
hemolysis), only about one third of the patients reach a hemoglobin value about 11gr/dL, and
the remaining patients on eculizumab continue to exhibit moderate to severe (i.e.,transfusiondependent) anemia, in about equal proportions (Risitano A.M. et al., Blood 113:4094-100
(2009)). As described in Risitano et al., Mini-Reviews in Medicinal Chemistry 11:528-535
(2011), it was demonstrated that PNH patients on eculizumab contained large amounts of C3
fragments bound to their PNH erythrocytes (while untreated patients did not). This finding
led to the recognition that in eculizumab-treated PNH patients, PNH RBCs that are no longer
hemolyzed due to C5 blockade now can accumulate copious amounts of membrane-bound
C3 fragments, which operate as opsonins, resulting in their entrapment in the
reticuloendothelial cells through specific C3 receptors and subsequent extravascular
hemolysis. Thus, while preventing intravascular hemolysis and the resulting sequelae,
eculizumab therapy simply diverts the disposition of these RBCs from intravascular to
extravascular hemolysis, resulting in substantial residual untreated anemia in many patients
(Risitano A.M. et al., Blood 113:4094-100 (2009)). Therefore, therapeutic strategies in
addition to the use of eculizumab are needed for those patients developing C3-fragment
mediated extravascular hemolysis, because they continue to require red cell transfusions.
Such C3 fragment targeting approaches have demonstrated utility in experimental systems
(Lindorfer et al., Blood 115:2283-91, 2010).
Complement-initiating mechanisms in PNH
The causal link between defective expression of the negative complement regulators
CD55 and CD59 in PNH, combined with the effectiveness of eculizumab in preventing
intravascular hemolysis, clearly define PNH as a condition caused by the complement
system. While this paradigm is widely accepted, the nature of the events initiating
complement activation, and the complement activation pathway(s) involved remain
unresolved. Because CD55 and CD59 negatively regulate the terminal amplification steps in
the complement cascade common to all complement initiation pathways, deficiency of these
molecules will lead to exaggerated terminal complement activation regardless of whether
complement activation is initiated by the lectin pathway, by the classical pathway or by
spontaneous turnover of the alternative pathway. Thus, in PNH patients, any complement
activation events that lead to C3b deposition on the RBC surface can trigger subsequent
amplification and pathological hemolysis (intravascular and/or extravascular) and precipitate
a hemolytic crisis. A clear mechanistic understanding of the molecular events triggering
hemolytic crisis in PNH patients has remained elusive. Because no complement initiating
event is overtly evident in PNH patients undergoing a hemolytic crisis, the prevailing view is
that complement activation in PNH may occur spontaneously owing to low level tick-over
activation of the alternative pathway, which is subsequently magnified by inappropriate
control of terminal complement activation due to lack of CD55 and CD59.
However, it is important to note that in its natural history, PNH usually develops or
exacerbates after certain events, such as an infection or an injury (Risitano, Biologics 2:205-
222 (2008)), which have been shown to trigger complement activation. This complement
activation response is not dependent on prior immunity of the host towards the inciting
pathogen, and hence likely does not involve the classical pathway. Rather, it appears that
this complement activation response is initiated by lectin binding to foreign or “altered self”
carbohydrate patterns expressed on the surface of microbial agents or damaged host tissue.
Thus, the events precipitating hemolytic crisis in PNH are tightly linked to complement
activation initiated via lectins. This makes it very likely that lectin activation pathways
provide the initiating trigger that ultimately leads to hemolysis in PNH patients.
MASP-2 inhibitors to block opsonization and extravascular hemolysis of PNH RBCs
through the reticuloendothelial system
This section describes the inhibitory effects of MASP-2 inhibitory agents on
hemolysis in an in vitro model of PNH. The findings support the utility of MASP
blocking agents (including, but not limited to, antibodies that bind to and block the function
of MASP-2) to treat subjects suffering from aspects of PNH, and also the use of inhibitors of
MASP-2 to ameliorate the effects of C3-fragment-mediated extravascular hemolysis in PNH
patients undergoing therapy with a C5-inhibitor such as eculizumab.
As detailed above, PNH patients become anemic owing to two distinct mechanisms
of RBC clearance from circulation: intravascular hemolysis via activation of the membrane
attack complex (MAC), and extravascular hemolysis following opsonization with C3b and
subsequent clearance following complement receptor binding and uptake by the
reticuloendothelial system. The intravascular hemolysis is largely prevented when a patient
is treated with eculizumab. Because eculizumab blocks the terminal lytic effector
mechanism that occurs downstream of both the complement-initiating activation event as
well as the ensuing opsonization, eculizumab does not block extravascular hemolysis
(Risitano A.M. et al., Blood 113:4094-100 (2009)). Instead, RBCs that would have
undergone hemolysis in untreated PNH patients now can accumulate activated C3b proteins
on their surface, which augments uptake by the reticuloendothelial system and enhances their
extravascular hemolysis. Thus, eculizumab treatment effectively diverts RBC disposition
from intravascular hemolysis to extravascular hemolysis. As a result, some eculizumab25 treated PNH patients remain anemic. It follows that agents that block complement activation
upstream and prevent the opsonization of PNH RBCs may be particularly suitable to block
the extravascular hemolysis not prevented by eculizumab.
The data presented here demonstrate that MASP-2 dependent complement activation
is the dominant route for lectin-dependent opsonization. Therefore, MASP-2 inhibitory
agents are expected to be effective at limiting opsonization and inhibiting extravascular
hemolysis in PNH.
Using an in vitro model of PNH, we demonstrated that complement activation and the
resulting hemolysis in PNH are indeed initiated, at least in part, by MASP-2 dependent
complement activation and that it is not an independent function of the alternative pathway.
These studies used mannan-sensitized RBCs of various mouse strains, including RBCs from
Crry-deficient mice (an important negative regulator of the terminal complement pathway in
mice) as well as RBCs from CD55/CD59-deficient mice, which lack the same complement
regulators that are absent in PNH patients). When Mannan-sensitized Crry-deficient RBCs
were exposed to complement-sufficient human serum, the RBCs effectively hemolysed at a
serum concentration of 3% (FIGURE 40) while complement-deficient serum (HI: heat10 inactivated) was not hemolytic. Remarkably, complement-sufficient serum in the presence
of anti-MASP-2 antibody had reduced hemolytic activity, and 6% serum was needed for
effective hemolysis (FIGURE 40). Similar observations were made when CD55/CD59-
deficient RBCs were tested (FIGURE 42). Complement-sufficient human serum
supplemented with anti-MASP-2 monoclonal antibody was about two-fold less effective than
untreated serum in supporting hemolysis. Furthermore, higher concentrations of serum
treated with anti-MASP-2 monoclonal antibody were needed to promote effective hemolysis
of untreated WT RBCs compared to untreated serum (FIGURE 40). Collectively, these data
indicate that MASP-2 dependent complement activation contributes significantly to the
hemolysis response. The data presented herein reveals the following pathogenic mechanisms
for anemia in PNH: intravascular hemolysis due to unregulated activation of terminal
complement components and lysis of RBC by formation of MAC, and extravascular
hemolysis caused by opsonization of RBCs by C3b, which is initiated predominately by
MASP-2 dependent complement activation. Thus, MASPinhibitory agents are expected
to significantly reduce intravascular hemolysis in PNH patients.
Extravascular hemolysis, a less dramatic, yet equally important mechanism of RBC
destruction that leads to anemia in PNH, is primarily the result of opsonization by C3b,
which is predominantly mediated by MASP-2 dependent complement activation. Thus,
MASPinhibitory agents will preferentially block RBC opsonization and C3b and the
ensuing extravascular hemolysis in PNH. This unique therapeutic activity of MASP
inhibitory agents is expected to provide a significant treatment benefit to all PNH patients as
no treatment currently exists for this pathogenic process.
MASP-2 inhibitors as adjunct treatment to terminal complement blocking agents:
The data presented herein detail two pathogenic mechanisms for RBC clearance and
anemia in PNH: the intravascular hemolysis initiated, at least in part, by MASP-2 dependent
complement activation, and thus expected to be effectively inhibited by a MASPinhibitory
agent, and extravascular hemolysis due to C3b opsonization driven by MASP-2, and thus
effectively prevented by a MASPinhibitory agent.
It is well documented that both intravascular and extravascular mechanisms of
hemolysis lead to anemia in PNH patients (Risitano et al., Blood 113:4094-4100 (2009)).
Therefore, in the setting of PNH, inhibition of MASP-2 would be expected to address both
intravascular and extravascular hemolysis, providing a significant advantage over the C5
inhibitor eculizumab. Accordingly, it is expected that a MASPblocking agent that inhibits
intravascular hemolysis and prevents extravascular hemolysis is expected to be effective in
preventing the degree of anemia that develops in PNH patients.
It is also known that C5-blocking agents (such as eculizumab) effectively block
intravascular hemolysis but do not interfere with opsonization. This leaves anti-C5-treated
PNH patients with substantial residual anemia due to extravascular hemolysis mediated by
MASP-2 dependent complement activation that remains untreated. Therefore, it is expected
that a C5-blocking agent (such as eculizumab) that prevents intravascular hemolysis in
combination with a MASP-2 inhibitory agent that prevents extravascular hemolysis will be
more effective than either agent alone in preventing the anemia that develops in PNH
patients. In fact, the combination of an anti-C5 and a MASPinhibitory agent is expected
to prevent all relevant mechanisms of RBC destruction in PNH and thus reduce or block all
symptoms of anemia in PNH.
Other agents that block the terminal amplification loop of the complement system
leading to C5 activation and MAC deposition (including, but not limited to agents that block
Properdin, factor B or factor D or enhance the inhibitory activity of factor I, factor H or other
complement inhibitory factors) are also expected to inhibit intravascular hemolysis.
However, these agents are not expected to interfere with MASPmediated opsonization in
PNH patients. This leaves PNH patients treated with such agents with substantial residual
anemia due to extravascular hemolysis mediated by MASP-2 dependent complement
activation that remains untreated. Therefore, it is expected that treatment with such agents
that prevent intravascular hemolysis in combination with a MASPinhibitory agent that
prevents extravascular hemolysis will be more effective than either agent alone in preventing
the anemia that develops in PNH patients. In fact, the combination of such agents and a
MASP-2 inhibitory agent is expected to prevent all or a large majority of the relevant
mechanisms of RBC destruction in PNH and thus block all or a large majority of the
symptoms of anemia in PNH.
Inhibition of MASP-2 improves survival in subjects infected with Neisseria
meningitidis
As described in Examples 30-32 and shown in FIGURES 33-37, inhibition of MASP10 2 does not reduce survival following infection with Neisseria meningitidis. To the contrary,
it was surprisingly discovered that MASP-2 inhibition significantly improved survival
(FIGURES 33 and 34) as well as illness scores (FIGURE 36) in these studies.
Administration of anti-MASP2 antibody yielded the same result (FIGURE 37), eliminating
secondary or compensatory effects in the knockout-mouse strain as a possible cause. These
favorable outcomes in MASPablated animals were associated with a more rapid
elimination of Neisseria from the blood (FIGURE 35). Also, as described herein, incubation
of Neisseria with human serum killed Neisseria (FIGURE 38). Furthermore, addition of a
functional monoclonal antibody specific for human MASP-2 that blocks MASPdependent
lectin pathway complement activation, but not administration of an isotype control
monoclonal antibody, enhanced this killing response.
In the context of lectin-dependent complement activation by Neisseria, blockade of MASP2-enhanced lytic destruction of the organism in vitro (FIGURE 38). Because lysis of
Neisseria is the main protective mechanism in the naïve host, blockade of MASP-2 in vivo
increases Neisseria clearance and leads to enhanced killing. These results are surprising, and
provide a significant advantage over treatment with eculizumab, which has been shown to
increase susceptibility to life-threatening and fatal meningococcal infections (Dmytrijuk A.,
et al., The Oncologist 13:993-1000 (2008)).
In accordance with the foregoing, in one aspect, the invention provides a method for
treating paroxysmal nocturnal hemoglobinuria (PNH) by administering a composition
comprising a therapeutically effective amount of a MASP-2 inhibitory agent in a
pharmaceutical carrier to a subject suffering from PNH or a condition resulting from PNH
(e.g., anemia, hemoglobin in the urine and thrombosis). The MASP-2 inhibitory agent is
administered systemically to the subject suffering from PNH or a condition resulting from
PNH, such as by intra-arterial, intravenous, intramuscular, inhalational, subcutaneous or
other parenteral administration, or potentially by oral administration for non-peptidergic
agents.
THE ROLE OF MASP-2 IN THROMBOTIC MICROANGIOPATHIES, INCLUDING
HEMOLYTIC UREMIC SYNDROME (HUS), ATYPICAL HEMOLYTIC
UREMIC SYNDROME (AHUS) AND THROMBOTIC THROMBOCYTOPENIC
PURPURA (TTP), AND THERAPEUTIC METHODS USING MASP-2
INHIBITORY AGENTS
Overview
Thrombotic microangiopathy (TMA) is a pathology characterized by blood clots in
small blood vessels (Benz, K.; et al., Curr Opin Nephrol Hypertens 19(3):242–7 (2010)).
Stress or injury to the underlying vascular endothelium is believed to be a primary driver.
Clinical and laboratory findings of TMA include thrombocytopenia, anemia, purpura, and
renal failure. The classic TMAs are hemolytic uremic syndrome (HUS) and thrombotic
thrombocytopenic purpura (TTP). The characteristic underlying pathological feature of
TMAs are platelet activation and the formation of microthrombi in the small arterioles and
venules. Complement activation initiated, at least in part, by an injury or stress to
microvascular endothelium, is also implicated in other TMAs including catastrophic
antiphospholipid syndrome (CAPS), systemic Degos disease, and TMAs secondary to
cancer, cancer chemotherapy and transplantation.
Direct evidence for a pathological role of complement in a host of nephritides is
provided by studies of patients with genetic deficiencies in specific complement
components. A number of reports have documented an association of renal injury with
deficiencies of complement regulatory factor H (Ault, B.H., Nephrol. 14:1045-1053, 2000;
Levy, M., et al., Kidney Int. 30:949-56, 1986; Pickering, M.C., et al., Nat. Genet. 31:424-8,
2002). Factor H deficiency results in low plasma levels of factor B and C3 due to activationrelated consumption of these components. Circulating levels of C5b-9 are also elevated in
the serum of these patients, implying complement activation. Membranoproliferative
glomerulonephritis (MPGN) and idiopathic hemolytic uremic syndrome (HUS) are
associated with factor H deficiency or mutations of factor H. Factor H-deficient pigs
(Jansen, J.H., et al., Kidney Int. 53:331-49, 1998) and factor-H knockout mice (Pickering,
M.C., 2002) display MPGN-like symptoms, confirming the importance of factor H in
complement regulation. Deficiencies of other complement components are associated with
renal disease, secondary to the development of systemic lupus erythematosus (SLE)
(Walport, M.J., Davies, et al., Ann. N.Y. Acad. Sci. 815:267-81, 1997). Deficiency for C1q,
C4 and C2 predispose strongly to the development of SLE via mechanisms relating to
defective clearance of immune complexes and apoptotic material. In many of these SLE
patients lupus nephritis occurs, characterized by the deposition of immune complexes
throughout the glomerulus.
aHUS
Atypical hemolytic uremic syndrome (aHUS) is part of a group of conditions termed
“Thrombotic microangiopathies.” In the atypical form of HUS (aHUS), the disease is
associated with defective complement regulation and can be either sporadic or familial.
Familial cases of aHUS are associated with mutations in genes coding for complement
activation or complement regulatory proteins, including complement factor H, factor I, factor
B, membrane cofactor CD46 as well as complement factor H-related protein 1 (CFHR1) and
complement factor H-related protein 3 (CFHR3). (Zipfel, P.F., et al., PloS Genetics
3(3):e41 (2007)). The unifying feature of this diverse array of genetic mutations associated
with aHUS is a predisposition to enhanced complement activation on cellular or tissue
surfaces. Therefore, one aspect of the present invention comprises treating a patient
suffering with aHUS that is associated with a factor H defiency by administering an effective
amount of a MASP-2 inhibitory agent. Another aspect of the present invention comprises
treating a patient suffering with HUS that is associated with a factor I, factor B, membrane
cofactor CD46, CFHR1 or CFHR3 deficiency by administering an effective amount of a
MASP-2 inhibitory agent.
Significant progress has been made recently toward the understanding of the
molecular pathophysiology underlying enhanced complement activation in aHUS caused by
the diverse set of mutant complement factors. This mechanism is best understood for factor
H mutations. Factor H is an abundant serum protein comprising 20 short consensus repeat
(SCR) domains that acts as a negative regulator of complement activation both in solution as
well as on host cell surfaces. It targets the activated form of C3 and, together with factor I
and other cofactors, promotes its inactivation, forestalling further complement activation. To
effectively control complement activation on host cell surfaces, factor H needs to interact
with host cells, which is mediated by SCR domains 16-20. All factor H mutations associated
with aHUS described to date are clustered in the C-terminal region encompassing (SCR)
domains 16-20. These mutant factor H proteins are fully functional in controlling C3
activation in solution, but are unable to interact with host cell surfaces and consequently
cannot control C3 activation on cellular surfaces (Exp Med 204(6):1249-56 (2007)). Thus,
certain mutations of factor H are associated with aHUS because the mutant factor H protein
fails to interact with host cell surfaces and thus cannot effectively down modulate
complement activation on host cell surfaces, including the microvascular endothelium. As a
result, once initial C3 activation has occurred, subsequent complement activation on
microvascular endothelial surfaces proceeds unabated in patients with factor H mutations.
This uncontrolled activation of complement ultimately leads to progressive injury to the
vascular endothelium, subsequent platelet aggregation and microvascular coagulation, and
hemolysis caused by sheer stress of RBC passage through partially occluded microvessels.
Thus, aHUS disease manifestations and clinical and laboratory findings are directly linked to
a defect in the negative regulation of complement on the surface of the microvascular
endothelium.
Analogous to factor H mutation, loss-of-function mutations in the negative
complement modulators factor I and membrane cofactor protein (CD46) are also linked to
aHUS. The opposite has been observed for factor B the C3 protein in that aHUS was found
to be associated with gain-of-function mutations in these proteins (Pediatr Nephrol
(12):2431-42 (2010)). Thus, a host of converging data implicates complement activation
in aHUS pathogenesis. This notion is most convincingly supported by the therapeutic
efficacy ofeculizumab, a monoclonal antibody that blocks the terminal complement protein
C5 in the treatment of aHUS.
While the central role of complement as an effector mechanism in aHUS is widely
accepted, the triggers initiating complement activation and the molecular pathways involved
are unresolved. Not all individuals carrying the above described mutations develop aHUS.
In fact, familial studies have suggested that the penetrance of aHUS is only ~50% (Ann Hum
Genet 74(1):17-26 (2010)). The natural history of the disease suggests that aHUS most often
develops after an initiating event such as an infectious episode or an injury. Infectious agents
are well known to activate the complement system. In the absence of pre-existing adaptive
immunity, complement activation by infectious agents may be primarily initiated via the
lectin pathway. Thus, lectin pathway activation triggered by an infection may represent the
initiating trigger for subsequent pathological amplification of complement activation in
aHUS-predisposed individuals, which may ultimately lead to disease progression.
Accordingly, another aspect of the present invention comprises treating a patient suffering
with aHUS secondary to an infection by administering an effective amount of a MASP-2
inhibitory agent.
Other forms of injury to host tissue will activate complement via the lectin pathway,
in particular injury to the vascular endothelium. Human vascular endothelial cells subject to
oxidative stress for example respond by expressing surface moieties that bind lectins and
activate the lectin pathway of complement (Am J. Pathol 156(6):1549-56 (2000)). Vascular
injury following ischemia/reperfusion also activates complement via the lectin pathway in
vivo (Scand J Immunol 61(5):426-34 (2005)). Lectin pathway activation in this setting has
pathological consequences for the host, and inhibition of the lectin pathway by blocking
MASP-2 prevents further host tissue injury and adverse outcomes (Schwaeble PNAS 2011).
Thus, other processes that precipitate aHUS are also known to activate the lectin
pathway of complement. It is therefore likely that the lectin pathway may represent the
initial complement activating mechanism that is inappropriately amplified in a deregulated
fashion in individuals genetically predisposed to aHUS, thus initiating aHUS pathogenesis.
By inference, agents that block activation of complement via the lectin pathway, including
anti-MASP-2 antibodies, are expected to prevent disease progression or reduce exacerbations
in aHUS susceptible individuals.
In further support of this concept, recent studies have identified S. pneumonia as an
important etiological agent in pediatric cases of aHUS. (Nephrology (Carlton), 17:48-52
(2012); Pediatr Infect Dis J. 30(9):736-9 (2011)). This particular etiology appears to have an
unfavorable prognosis, with significant mortality and long-term morbidity. Notably, these
cases involved non-enteric infections leading to manifestations of microangiopathy, uremia
and hemolysis without evidence of concurrent mutations in complement genes known to
predispose to aHUS. It is important to note that S. pneumonia is particularly effective at
activating complement, and does so predominantly through the lectin pathway. Thus, in
cases of non-enteric HUS associated with pneumococcal infection, manifestations of
microangiopathy, uremia and hemolysis are expected to be driven predominantly by
activation of the lectin pathway, and agents that block the lectin pathway, including antiMASP-2 antibodies, are expected to prevent progression of aHUS or reduce disease severity
in these patients. Accordingly, another aspect of the present invention comprises treating a
patient suffering with non-enteric aHUS that is associated with S. pneumonia infection by
administering an effective amount of a MASP-2 inhibitory agent.
In accordance with the foregoing, in some embodiments, in the setting of a subject at
risk for developing renal failure associated with aHUS, a method is provided for decreasing
the likelihood of developing aHUS, or of developing renal failure associated with aHUS,
comprising administering an amount of an MASP-2 inhibitory agent for a time period
effective to ameliorate or prevent renal failure in the subject. In some embodiments, the
method further comprises the step of determining whether a subject is at risk for developing
aHUS prior to the onset of any symptoms associated with aHUS. In other embodiments, the
method comprises determining whether a subject is a risk for developing aHUS upon the
onset of at least one or more symptoms indicative of aHUS (e.g., the presence of anemia,
thrombocytopenia and/or renal insufficiency) and/or the presence of thrombotic
microangiopathy in a biopsy obtained from the subject. The determination of whether a
subject is at risk for developing aHUS comprises determining whether the subject has a
genetic predisposition to developing aHUS, which may be carried out by assessing genetic
information (e.g. from a database containing the genotype of the subject), or performing at
least one genetic screening test on the subject to determine the presence or absence of a
genetic marker associated with aHUS (i.e., determining the presence or absence of a genetic
mutation associated with aHUS in the genes encoding complement factor H (CFH), factor I
(CFI), factor B (CFB), membrane cofactor CD46, C3, complement factor H-related protein 1
(CFHR1), or THBD (encoding the anticoagulant protein thrombodulin) or complement factor
H-related protein 3 (CFHR3), or complement factor H-related protein 4 (CFHR4)) either via
genome sequencing or gene-specific analysis (e.g., PCR analysis), and/or determining
whether the subject has a family history of aHUS. Methods of genetic screening for the
presence or absence of a genetic mutation associated with aHUS are well established, for
example, see Noris M et al. “Atypical Hemolytic-Uremic Syndrome,” 2007 Nov 16 [Updated
2011 Mar 10]. In: Pagon RA, Bird TD, Dolan CR, et al., editors. GeneReviews™, Seattle
(WA): University of Washington, Seattle.
For example, overall the penetrance of the disease in those with mutations of
complement factor H (CFH) is 48%, and the penetrance for mutations in CD46 is 53%, for
mutations in CFI is 50%, for mutations in C3 is 56% and for mutations in THBD is 64%
(Caprioli J. et al., Blood, 108:1267-79 (2006); Noris et al., Clin J Am Soc Nephrol 5:1844-59
(2010)). As described in Caprioli et al., (2006), supra, a substantial number of individuals
with a mutation in complement Factor H (CFH) never develop aHUS, and it is postulated
that suboptimal CFH activity in these individuals is sufficient to protect the host from the
effects of complement activation in physiological conditions, however, suboptimal CFH
activity is not sufficient to prevent C3b from being deposited on vascular endothelial cells
when exposure to an agent that activates complement produces higher than normal amounts
of C3b. Accordingly, in one embodiment, a method is provided for inhibiting MASP
dependent complement activation in a subject suffering from, or at risk for developing nonFactor H-dependent atypical hemolytic uremic syndrome, comprising administering to the
subject a composition comprising an amount of a MASP-2 inhibitory agent effective to
inhibit MASPdependent complement activation. In another embodiment, a method is
provided for inhibiting MASPdependent complement activation in a subject at risk for
developing Factor H-dependent atypical hemolytic uremic syndrome, comprising
periodically monitoring the subject to determine the presence or absence of anemia,
thrombocytopenia or rising creatinine, and treating with a MASP-2 inhibitory agent upon the
determination of the presence of anemia thrombocytopenia, or rising creatinine. In another
embodiment, a method is provided for reducing the likelihood that a subject at risk for
developing Factor H-dependent aHUS will suffer clinical symptoms associated with aHUS,
comprising administering a MASP-2 inhibitory agent prior to, or during, or after an event
known to be associated with triggering aHUS clinical symptoms, for example, drug exposure
(e.g., chemotherapy), infection (e.g., bacterial infection), malignancy, an injury, organ or
tissue transplant, or pregnancy.
In one embodiment, a method is provided for reducing the likelihood that a subject at
risk for developing aHUS will suffer clinical symptoms associated with aHUS, comprising
periodically monitoring the subject to determine the presence or absence of anemia,
thrombocytopenia or rising creatinine, and treating with a MASP-2 inhibitory agent upon the
determination of the presence of anemia, thrombocytopenia, or rising creatinine.
In another embodiment, a method is provided for reducing the likelihood that a
subject at risk for developing aHUS will suffer clinical symptoms associated with aHUS
comprising administering a MASP-2 inhibitory agent prior to, or during, or after an event
known to be associated with triggering aHUS clinical symptoms, for example, drug exposure
(e.g., chemotherapy), infection (e.g., bacterial infection), malignancy, an injury, organ or
tissue transplant, or pregnancy.
In some embodiments, the MASP-2 inhibitory agent is administered for a time period
of at least one, two, three, four days, or longer, prior to, during, or after the event associated
with triggering aHUS clinical symptoms and may be repeated as determined by a physician
until the condition has been resolved or is controlled. In a pre-aHUS setting, the MASP-2
inhibitory agent may be administered to the subject systemically, such as by intra-arterial,
intravenous, intramuscular, inhalational, nasal, subcutaneous or other parenteral
administration.
In some embodiments, in the setting of initial diagnosis of aHUS, or in a subject
exhibiting one or more symptoms consistent with a diagnosis of aHUS (e.g., the presence of
anemia, thrombocytopenia and/or renal insufficiency), the subject is treated with an effective
amount of a MASP-2 inhibitory agent (e.g., an anti-MASP-2 antibody) as a first line therapy
in the absence of plasmapheresis, or in combination with plasmapheresis. As a first line
therapy, the MASP-2 inhibitory agent may be administered to the subject systemically, such
as by intra-arterial, intravenous, intramuscular, inhalational, nasal, subcutaneous or other
parenteral administration. In some embodiments, the MASP-2 inhibitory agent is
administered to a subject as a first line therapy in the absence of plasmaphersis to avoid the
potential complications of plasmaphersis including hemorrhage, infection, and exposure to
disorders and/or allergies inherent in the plasma donor, or in a subject otherwise averse to
plasmapheresis, or in a setting where plasmapheresis is unavailable.
In some embodiments, the method comprises administering a MASP-2 inhibitory
agent to a subject suffering from aHUS via a catheter (e.g., intravenously) for a first time
period (e.g., at least one day to a week or two weeks) followed by administering a MASP-2
inhibitory agent to the subject subcutaneously for a second time period (e.g., a chronic phase
of at least two weeks or longer). In some embodiments, the administration in the first and/or
second time period occurs in the absence of plasmapheresis. In some embodiments, the
method further comprises determining the level of at least one complement factor (e.g., C3,
C5) in the subject prior to treatment, and optionally during treatment, wherein the
determination of a reduced level of at least one complement factor in comparison to a
standard value or healthy control subject is indicative of the need for continued treatment
with the MASP-2 inhibitory agent.
In some embodiments, the method comprises administering a MASP-2 inhibitory
agent, such as an anti-MASP-2 antibody, to a subject suffering from, or at risk for
developing, aHUS either intravenously, intramuscularly, or preferably, subcutaneously.
Treatment may be chronic and administered daily to monthly, but preferably every two
weeks. The anti-MASP-2 antibody may be administered alone, or in combination with a C5
inhibitor, such as eculizamab.
HUS
Like atypical HUS, the typical form of HUS displays all the clinical and laboratory
findings of a TMA. Typical HUS, however, is often a pediatric disease and usually has no
familial component or direct association with mutations in complement genes. The etiology
of typical HUS is tightly linked to infection with certain intestinal pathogens. The patients
typically present with acute renal failure, hemoglobinuria, and thrombocytopenia, which
typically follows an episode of bloody diarrhea. The condition is caused by an enteric
infection with Shigella dissenteria, Salmonella or shiga toxin-like producing
enterohemorrhagic strains of E. Coli. such as E.Coli O157:H7. The pathogens are acquired
from contaminated food or water supply. HUS is a medical emergency and carries a 5-10%
mortality. A significant portion of survivors develop chronic kidney disease (Corrigan and
Boineau, Pediatr Rev 22 (11): 365–9 (2011)) and may require kidney transplantation.
The microvascular coagulation in typical HUS occurs predominantly, though not
exclusively, in the renal microvasculature. The underlying pathophysiology is mediated by
Shiga toxin (STX). Excreted by enteropathic microbes into the intestinal lumen, STX
crosses the intestinal barrier, enters the bloodstream and binds to vascular endothelial cells
via the blobotriaosyl ceramide receptor CD77 (Boyd and Lingwood Nephron 51:207 (1989)),
which is preferentially expressed on glomerular endothelium and mediates the toxic effect of
STX. Once bound to the endothelium, STX induces a series of events that damage vascular
endothelium, activate leukocytes and cause vWF-dependent thrombus formation (Forsyth et
al., Lancet 2: 411–414 (1989); Zoja et al., Kidney Int. 62: 846–856 (2002); Zanchi et al., J.
Immunol. 181:1460–1469 (2008); Morigi et al., Blood 98: 1828–1835 (2001); Guessou et al.,
Infect. Immun., 73: 8306–8316 (2005)). These microthrombi obstruct or occlude the
arterioles and capillaries of the kidney and other organs. The obstruction of blood flow in
arterioles and capillaries by microthrombi increases the shear force applied to RBCs as they
squeeze through the narrowed blood vessels. This can result in destruction of RBC by shear
force and the formation of RBC fragments called schistocytes. The presence of schistocytes
is a characteristic finding in HUS. This mechanism is known as microangiopathic
hemolysis. In addition, obstruction of blood flow results in ischemia, initiating a
complement-mediated inflammatory response that causes additional damage to the affected
organ.
The lectin pathway of complement contributes to the pathogenesis of HUS by two
principle mechanisms: 1) MASPmediated direct activation of the coagulation cascade
caused by endothelial injury, and 2) lectin-mediated subsequent complement activation
induced by the ischemia resulting from the initial occlusion of microvascular blood flow.
STX injures microvascular endothelial cells, and injured endothelial cells are known
to activate the complement system. As detailed above, complement activation following
endothelial cell injury is driven predominantly by the lectin pathway. Human vascular
endothelial cells subject to oxidative stress respond by expressing surface moieties that bind
lectins and activate the lectin pathway of complement (Collard et al., Am J Pathol.
156(5):1549-56 (2000)). Vascular injury following ischemia reperfusion also activates
complement via the lectin pathway in vivo (Scand J Immunol 61(5):426-34 (2005)).Lectin
pathway activation in this setting has pathological consequences for the host, and inhibition
of the lectin pathway by blockade of MASP-2 prevents further host tissue injury and adverse
outcomes (Schwaeble et al., PNAS (2011)). In addition to complement activation, lectindependent activation of MASP-2 has been shown to result in cleavage of prothrombin to
form thrombin and to promote coagulation. Thus, activation of the lectin pathway of
complement by injured endothelial cells can directly activate the coagulation system. The
lectin pathway of complement, by virtue of MASPmediated prothombin activation,
therefore is likely the dominant molecular pathway linking the initial endothelial injury by
STX to the coagulation and microvascular thrombosis that occurs in HUS. It is therefore
expected that lectin pathway inhibitors, including, but not limited to, antibodies that block
MASP-2 function, will prevent or mitigate microvascular coagulation, thrombosis and
hemolysis in patients suffering from HUS. Indeed, administration of anti-MASP-2 antibody
profoundly protects mice in a model of typical HUS. As described in Example 36 and shown
in FIGURE 45, all control mice exposed to STX and LPS developed severe HUS and became
moribund or died within 48 hours. On the other hand, as further shown in FIGURE 45, all
mice treated with an anti-MASP-2 antibody and then exposed to STX and LPS survived
(Fisher’s exact p<0.01; N=5). Thus, anti-MASP-2 therapy profoundly protects mice in this
model of HUS. It is expected that administration of a MASP-2 inhibitory agent, such as a
MASP-2 antibody, will be effective in the treatment of HUS patients and provide protection
from microvascular coagulation, thrombosis, and hemolysis caused by infection with
enteropathic E. coli or other STX-producing pathogens.
While shown here for HUS caused by STX, it is expected that anti-MASP-2 therapy
will also be beneficial for HUS-like syndromes due to endothelial injury caused by other
toxic agents. This includes agents such as mitomycin, ticlopidine, cycplatin, quinine,
cyclosporine, bleomycin as well as other chemotherapy drugs and immunosuppresssive
drugs. Thus, it is expected that anti-MASP-2 antibody therapy, or other modalities that
inhibit MASP-2 activity, will effectively prevent or limit coagulation, thrombus formation,
and RBC destruction and prevent renal failure in HUS and other TMA related diseases (i.e.,
aHUS and TTP).
Patients suffering from HUS often present with diarrhea and vomiting, their platelet
counts are usually reduced (thrombocytopenia), and RBCs are reduced (anemia). A pre-HUS
diarrhea phase typically lasts for about four days, during which subjects at risk for
developing HUS typically exhibit one or more of the following symptoms in addition to
severe diarrhea: a hematocrit level below 30% with smear evidence of intravascular
erythrocyte destruction, thrombocytopenia (platelet count <150 x 103
/mm3
), and/or the
presence of impaired renal function (serum creatinine concentration greater than the upper
limit of reference range for age). The presence of oligoanuria (urine output ≤0.5 mL/kg/h for
>1 day) can be used as a measure for progression towards developing HUS (see C. Hickey et
al., Arch Pediatr Adolesc Med 165(10):884-889 (2011)). Testing is typically carried out for
the presence of infection with E. coli bacteria (E.coli O157:H7), or Shigella or Salmonella
species. In a subject testing positive for infection with enterogenic E. coli (e.g., E. coli
0157:H7), the use of antibiotics is contra-indicated because the use of antibiotics may
increase the risk of developing HUS through increased STX production (See Wong C. et al.,
N Engl J. Med 342:1930-1936 (2000). For subjects testing positive for Shigella or
Salmonella, antibiotics are typically administered to clear the infection. Other well
established first-line therapy for HUS includes volume expansion, dialysis and
plasmapheresis.
In accordance with the foregoing, in some embodiments, in the setting of a subject
suffering from one or more symptoms associated with a pre-HUS phase and at risk for
developing HUS (i.e., the subject exhibits one or more of the following: diarrhea, a
hematocrit level less than 30% with smear evidence of intravascular erythrocyte destruction,
thrombocytopenia (platelet count less than 150 x 103
/mm3 20 ), and/or the presence of impaired
renal function (serum creatinine concentration greater than the upper limit of reference range
for age)), a method is provided for decreasing the risk of developing HUS, or of decreasing
the likelihood of renal failure in the subject, comprising administering an amount of an
MASP-2 inhibitory agent for a time period effective to ameliorate or prevent impaired renal
function. In some embodiments, the MASP-2 inhibitory agent is administered for a time
period of at least one, two, three, four or more days, and may be repeated as determined by a
physician until the condition has been resolved or is controlled. In a pre-HUS setting, the
MASP-2 inhibitory agent may be administered to the subject systemically, such as by
intra-arterial, intravenous, intramuscular, inhalational, nasal, oral, subcutaneous or other
parenteral administration.
The treatment of E. coli 0157:H7 infection with bactericidal antibiotics, particularly
β-lactams, has been associated with an increased risk of developing HUS (Smith et al.,
Pediatr Infect Dis J 31(1):37-41 (2012).In some embodiments, in the setting of a subject
suffering from symptoms associated with a pre-HUS phase, wherein the subject is known to
have an infection with enterogenic E. coli for which the use of antibiotics is contra-indicated
(e.g., E. coli 0157:H7), a method is provided for decreasing the risk of developing HUS, or
of decreasing the likelihood of renal failure in the subject, comprising administering an
amount of a MASP-2 inhibitory agent for a first time period effective to inhibit or prevent the
presence of oligoanuria in the subject (e.g., at least one, two, three or four days), wherein the
administration of the MASP-2 inhibitory agent during the first time period occurs in the
absence of an antibiotic. In some embodiments, the method further comprises administering
the MASP-2 inhibitory agent to the subject in combination with an antibiotic for a second
time period (such as at least one to two weeks).
In other embodiments, in the setting of a subject suffering from symptoms associated
with a pre-HUS phase, wherein the subject is known to have an infection with Shigella or
Salmonella, a method is provided for decreasing the risk of developing HUS, or of
decreasing the likelihood of renal failure in the subject, comprising administering an amount
of a MASP-2 inhibitory agent and for a time period effective to inhibit or prevent the
presence of oligoanuria in the subject, wherein the administration of the MASP-2 inhibitory
agent is either in the presence or in the absence of a suitable antibiotic.
In some embodiments, in the setting of an initial diagnosis of HUS, or in a subject
exhibiting one or more symptoms consistent with a diagnosis of HUS (e.g., the presence of
renal failure, or microangiopathic hemolytic anemia in the absence of low fibrinogen, or
thrombocytopenia) the subject is treated with an effective amount of a MASP-2 inhibitory
agent (e.g. a anti-MASP-2 antibody) as a first-line therapy in the absence of plasmapheresis,
or in combination with plasmapheresis. As a first-line therapy, the MASP-2 inhibitory agent
may be administered to the subject systemically, such as by intra-arterial, intravenous,
intramuscular, inhalational, nasal, subcutaneous or other parenteral administration. In some
embodiments, the MASP-2 inhibitory agent is administered to a subject as a first line therapy
in the absence of plasmapheresis to avoid the complications of plasmapheresis such as
hemorrhage, infection, and exposure to disorders and/or allergies inherent in the plasma
donor, or in a subject otherwise averse to plasmaphoresis, or in a setting where
plasmapheresis is unavailable.
In some embodiments, the method comprises administering a MASP-2 inhibitory
agent to a subject suffering from HUS via a catheter (e.g., intravenously) for a first time
period (e.g., an acute phase lasting at least one day to a week or two weeks) followed by
administering a MASP-2 inhibitory agent to the subject subcutaneously for a second time
period (e.g., a chronic phase of at least two weeks or longer). In some embodiments, the
administration in the first and/or second time period occurs in the absence of plasmapheresis.
In some embodiments, the method further comprises determining the level of at least one
complement factor (e.g., C3, C5) in the subject prior to treatment, and optionally during
treatment, wherein the determination of a reduced level of the at least one complement factor
in comparison to a standard value or healthy control subject is indicative of the need for
treatment, and wherein the determination of a normal level is indicative of improvement.
In some embodiments, the method comprises administering a MASP-2 inhibitory
agent, such as an anti-MASP-2 antibody, to a subject suffering from, or at risk for
developing, HUS either subcutaneously or intravenously. Treatment is preferably daily, but
can be as infrequent as weekly or monthly. Treatment will continue for at least one week
and as long as 3 months. The anti-MASP-2 antibody may be administered alone, or in
combination with a C5 inhibitor, such as eculizamab.
TTP:
Thrombotic thrombocytopenic purpura (TTP) is a life threatening disorder of the
blood-coagulation system, caused by autoimmune or hereditary dysfunctions that activate the
coagulation cascade or the complement system (George, JN, N Engl J Med; 354:1927-35
(2006)). This results in numerous microscopic clots, or thomboses, in small blood vessels
throughout the body. Red blood cells are subjected to shear stress which damages their
membranes, leading to intravascular hemolysis. The resulting reduced blood flow and
endothelial injury results in organ damage, including brain, heart, and kidneys. TTP is
clinically characterized by thrombocytopenia, microangiopathic hemolytic anemia,
neurological changes, renal failure and fever. In the era before plasma exchange, the fatality
rate was 90% during acute episodes. Even with plasma exchange, survival at six months is
about 80%.
TTP may arise from genetic or acquired inhibition of the enzyme ADAMTS-13, a
metalloprotease responsible for cleaving large multimers of von Willebrand factor (vWF)
into smaller units. ADAMTS-13 inhibition or deficiency ultimately results in increased
coagulation (Tsai, H. J Am Soc Nephrol 14: 1072–1081, (2003)). ADAMTS-13 regulates the
activity of vWF; in its absence, vWF forms large multimers which are more likely to bind
platelets and predisposes patients to platelet aggregation and thrombosis in the
microvasculature.
Upshaw-Schulman syndrome (USS, also described as congenital TTP) is a congenital
deficiency of ADAMTS13 activity due to ADAMTS13 gene mutations (Schulman et al.,
Blood, 16(1):943-57, 1960; Upshaw et al., New Engl. J. Med, 298 (24):1350-2, 1978).
Numerous mutations in ADAMTS13 have been identified in individuals with congenital TTP
(Kinoshita et al., International Journal of Hematology, 74:101-108 (2001); Levy et al.,
Nature, 413 (6855):488-494 (2001); Kokame et al., PNAS 99(18):11902-11907 (2002);
Savasan et al., Blood, 101:4449-4451 (2003); Matsumoto et al., Blood, 103:1305-1310
(2004) and Fujimura et al., Brit. J. Haemat 144:742-754 (2008)). Subjects with USS
typically have 5-10% of normal ADAMTS13 activity (Kokame et al., PNAS 99(18):11902-
11907, 2002). Although acquired TTP and USS have some similarities, USS has some
important differences in clinical features. USS usually presents in infancy or childhood and
is characterized by severe hyperbilirubinemia with negative Coombs test soon after birth,
response to fresh plasma infusion, and frequent relapses (Savasan et al., Blood, 101:4449-
4451, 2003). In some cases, patients with this inherited ADAMTS13 deficiency have a mild
phenotype at birth and only develop symptoms associated with TTP in clinical situations
with increased von Willebrand factor levels, such as infection or pregnancy. For example,
Fujimura et al. reported 9 Japanese women from 6 families with genetically confirmed USS
who were diagnosed with the disorder during their first pregnancy. Thrombocytopenia
occurred during the second to third trimesters in each of their 15 pregnancies, often followed
by TTP. All of these women were found to be severely deficient in ADAMTS13 activity
(Fujimura et al., Brit. J. Haemat 144:742-754, 2008).
In accordance with the foregoing, in some embodiments, in the setting of a subject
with Upshaw-Schulman syndrome (USS) (i.e., the subject is known to be deficient in
ADAMTS13 activity and/or the subject is known to have one or more ADAMTS13 gene
mutation(s)), a method is provided for decreasing the likelihood of developing clinical
symptoms associated with congenital TTP (e.g., thrombocytopenia, anemia, fever, and/or
renal failure ) comprising administering an amount of a MASP-2 inhibitory agent (e.g., a
MASP-2 antibody) for a time period effective to ameliorate or prevent one or more clinical
symptoms associated with TTP. In some embodiments, the method further comprises the
step of determining whether a subject is at risk for developing symptoms associated with
congenital TTP prior to the onset of any symptoms associated with TTP, or upon the onset of
at least one or more symptoms indicative of TTP (e.g., the presence of anemia,
thrombocytopenia and/or renal insufficiency). The determination of whether a subject is at
risk for developing symptoms associated with congenital TTP (i.e., the subject has USS),
comprises determining whether the subject has a mutation in the gene encoding
ADAMTS13, and/or determining whether the subject is deficient in ADAMTS13 activity,
and/or determining whether the subject has a family history of USS. Methods of genetic
screening for the presence or absence of a genetic mutation associated with USS are well
established, for example see Kinoshita et al., International Journal of Hematology, 74:101-
108 (2001); Levy et al., Nature, 413 (6855):488-494 (2001); Kokame et al., PNAS
99(18):11902-11907 (2002); Savasan et al., Blood, 101:4449-4451 (2003); Matsumoto et al.,
Blood, 103:1305-1310 (2004) and Fujimura et al., Brit. J. Haemat 144:742-754 (2008).
In one embodiment, a method is provided for reducing the likelihood that a subject
diagnosed with USS will suffer clinical symptoms associated with TTP comprising
periodically monitoring the subject to determine the presence or absence of anemia,
thrombocytopenia or rising creatinine, and treating with a MASP-2 inhibitory agent (e.g., a
MASP-2 antibody) upon the determination of the presence of anemia, thrombocytopenia or
rising creatinine, or upon the presence of an event known to be associated with triggering
TTP clinical symptoms, for example, drug exposure (e.g., chemotherapy), infection (e.g.
bacterial infection), malignancy, injury, transplant, or pregnancy.
In another embodiment, a method is provided for treating a subject with USS and
suffering from clinical symptoms associated with TTP comprising administering an amount
of a MASP-2 inhibitory agent (e.g., a MASP-2 antibody) for a time period effective to
ameliorate or prevent one or more clinical symptoms associated with TTP.
TTP can also develop due to auto-antibodies against ADAMTS-13. In addition, TTP
can develop during breast, gastrointestinal tract, or prostate cancer (George JN., Oncology
(Williston Park). 25:908-14 (2011)), pregnancy (second trimester or postpartum), George
JN., Curr Opin Hematol 10:339-344 (2003)), or is associated with diseases, such as HIV or
autoimmune diseases like systemic lupus erythematosis (Hamasaki K, et al., Clin
Rheumatol.22:355-8 (2003)). TTP can also be caused by certain drug therapies, including
heparin, Quinine, immunemediated ingredient, cancer chemotherapeutic agents (bleomycin,
cisplatin, cytosine arabinoside, daunomycin gemcitabine, mitomycin C, and tamoxifen),
cyclosporine A, oral contraceptives, penicillin, rifampin and anti-platelet drugs including
ticlopidine and clopidogrel (Azarm, T. et al., J Res Med Sci., 16: 353–357 (2011)). Other
factors or conditions associated with TTP are toxins such as bee venoms, sepsis, splenic
sequestration, transplantation, vasculitis, vascular surgery, and infections like Streptococcus
pneumonia and cytomegalovirus (Moake JL., N Engl J Med., 347:589–600 (2002)). TTP due
to transient functional ADAMTS-13 deficiency can occur as a consequence of endothelial
cell injury associated with S. pneumonia infection (Pediatr Nephrol., 26:631-5 (2011)).
Plasma exchange is the standard treatment for TTP (Rock GA, et al., N Engl J Med
325:393-397 (1991)). Plasma exchange replaces ADAMTS-13 activity in patients with
genetic defects and removes ADAMTS-13 autoantibodies in those patients with acquired
autoimmune TTP (Tsai, H-M, Hematol Oncol Clin North Am., 21(4): 609–v (2007)).
Additional agents such as immunosuppressive drugs are routinely added to therapy (George,
JN, N Engl J Med, 354:1927-35 (2006)). However, plasma exchange is not successful for
about 20% of patients, relapse occurs in more than a third of patients, and plasmapheresis is
costly and technically demanding. Furthermore, many patients are unable to tolerate plasma
exchange. Consequently there remains a critical need for additional and better treatments for
TTP.
Because TTP is a disorder of the blood coagulation cascade, treatment with
antagonists of the complement system may aid in stabilizing and correcting the disease.
While pathological activation of the alternative complement pathway is linked to aHUS, the
role of complement activation in TTP is less clear. The functional deficiency of
ADAMTS13 is important for the susceptibility of TTP, however it is not sufficient to cause
acute episodes. Environmental factors and/or other genetic variations may contribute to the
manifestation of TTP. For example, genes encoding proteins involved in the regulation of
the coagulation cascade, vWF, platelet function, components of the endothelial vessel
surface, or the complement system may be implicated in the development of acute
thrombotic microangiopathy (Galbusera, M. et al., Haematologica, 94: 166–170 (2009)). In
particular, complement activation has been shown to play a critical role; serum from
thrombotic microangiopathy associated with ADAMTS-13 deficiency has been shown to
cause C3 and MAC deposition and subsequent neutrophil activation which could be
abrogated by complement inactivation (Ruiz-Torres MP, et al., Thromb Haemost, 93:443-52
(2005)). In addition, it has recently been shown that during acute episodes of TTP there are
increased levels of C4d, C3bBbP, and C3a (M. Réti et al., J Thromb Haemost. Feb 28.(2012)
doi: 10.1111/j.1538-7836.2012.04674.x. [Epub ahead of print]), consistent with activation of
the classical/lectin and alternative pathways. This increased amount of complement
activation in acute episodes may initiate the terminal pathway activation and be responsible
for further exacerbation of TTP.
The role of ADAMTS-13 and vWF in TTP clearly is responsible for activation and
aggregation of platelets and their subsequent role in shear stress and deposition in
microangiopathies. Activated platelets interact with and trigger both the classical and
alternative pathways of complement. Platelet mediated complement activation increases the
inflammatory mediators C3a and C5a (Peerschke E et al., Mol Immunol, 47:2170-5 (2010)).
Platelets may thus serve as targets of classical complement activation in inherited or
autoimmune TTP.
As described above, the lectin pathway of complement, by virtue of MASP-2
mediated prothombin activation, is the dominant molecular pathway linking endothelial
injury to the coagulation and microvascular thrombosis that occurs in HUS. Similarly,
activation of the lectin pathway of complement may directly drive the coagulation system in
TTP. Lectin pathway activation may be initiated in response to the initial endothelium injury
caused by ADAMTS-13 deficiency in TTP. It is therefore expected that lectin pathway
inhibitors, including but not limited to antibodies that block MASP-2 function, will mitigate
the microangiopathies associated with microvascular coagulation, thrombosis, and hemolysis
in patients suffering from TTP.
Patients suffering from TTP typically present in the emergency room with one or
more of the following: purpura, renal failure, low platelets, anemia and/or thrombosis,
including stroke. The current standard of care for TTP involves intra-catheter delivery (e.g.,
intravenous or other form of catheter) of replacement plasmapheresis for a period of two
weeks or longer, typically three times a week, but up to daily. If the subject tests positive for
the presence of an inhibitor of ADAMTS13 (i.e., an endogenous antibody against
ADAMTS13), then the plasmapheresis may be carried out in combination with
immunosuppressive therapy (e.g., corticosteroids, rituxan, or cyclosporine). Subjects with
refractory TTP (approximately 20% of TTP patients) do not respond to at least two weeks of
plasmapheresis therapy.
In accordance with the foregoing, in one embodiment, in the setting of an initial
diagnosis of TTP or in a subject exhibiting one or more symptoms consistent with a
diagnosis of TTP (e.g., central nervous system involvement, severe thrombocytopenia (a
platelet count of less that or equal to 5000/µL if off aspirin, less than or equal to 20,000/µL if
on aspirin), severe cardiac involvement, severe pulmonary involvement, gastro-intestinal
infarction or gangrene), a method is provided for treating the subject with an effective
amount of a MASP-2 inhibitory agent (e.g., a anti-MASP-2 antibody) as a first line therapy
in the absence of plasmapheresis, or in combination with plasmapheresis. As a first-line
therapy, the MASP-2 inhibitory agent may be administered to the subject systemically, such
as by intra-arterial, intravenous, intramuscular, inhalational, nasal, subcutaneous or other
parenteral administration. In some embodiments, the MASP-2 inhibitory agent is
administered to a subject as a first-line therapy in the absence of plasmapheresis to avoid the
potential complications of plasmapheresis, such as hemorrhage, infection, and exposure to
disorders and/or allergies inherent in the plasma donor, or in a subject otherwise averse to
plasmapheresis, or in a setting where plasmapheresis is unavailable. In some embodiments,
the MASP-2 inhibitory agent is administered to the subject suffering from TTP in
combination (including co-administration) with an immunosuppressive agent (e.g.,
corticosteroids, rituxan or cyclosporine) and/or in combination with concentrated ADAMTS13.
In some embodiments, the method comprises administering a MASP-2 inhibitory
agent to a subject suffering from TTP via a catheter (e.g., intravenously) for a first time
period (e.g., an acute phase lasting at least one day to a week or two weeks) followed by
administering a MASP-2 inhibitory agent to the subject subcutaneously for a second time
period (e.g., a chronic phase of at least two weeks or longer). In some embodiments, the
administration in the first and/or second time period occurs in the absence of plasmapheresis.
In some embodiments, the method is used to maintain the subject to prevent the subject from
suffering one or more symptoms associated with TTP.
In another embodiment, a method is provided for treating a subject suffering from
refractory TTP (i.e., a subject that has not responded to at least two weeks of plasmaphoresis
therapy), by administering an amount of a MASP-2 inhibitor effective to reduce one or more
symptoms of TTP. In one embodiment, the MASP-2 inhibitor (e.g., an anti-MASP-2
antibody) is administered to a subject with refractory TTP on a chronic basis, over a time
period of at least two weeks or longer via subcutaneous or other parenteral administration.
Administration may be repeated as determined by a physician until the condition has been
resolved or is controlled.
In some embodiments, the method further comprises determining the level of at least
one complement factor (e.g., C3, C5) in the subject prior to treatment, and optionally during
treatment, wherein the determination of a reduced level of the at least one complement factor
in comparison to a standard value or healthy control subject is indicative of the need for
continued treatment with the MASP-2 inhibitory agent.
In some embodiments, the method comprises administering a MASP-2 inhibitory
agent, such as an anti-MASP-2 antibody, to a subject suffering from, or at risk for
developing, TTP either subcutaneously or intravenously. Treatment is preferably daily, but
can be as infrequent as biweekly. Treatment is continued until the subject’s platelet count is
greater than 150,000/ml for at least two consecutive days. The anti-MASP-2 antibody may
be administered alone, or in combination with a C5 inhibitor, such as eculizamab.
Degos Disease
Degos disease, also known as malignant atrophic papulosis, is a very rare TMA
affecting the endothelium of small vessels of skin, gastrointestinal tract, and CNS. This
vasculopathy causes occlusion of venules and artioles, resulting in skin lesions, bowel
ischemia, and CNS disorders including strokes, epilepsy and cognitive disorders. In the skin,
connective tissue necrosis is due to thrombotic occlusion of the small arteries. However, the
cause of Degos disease is unknown. Vasculitis, coagulopathy, or primary dysfunction of the
endothelial cells have been implicated. Degos disease has a 50% survival of only two to
three years. There is no effective treatment for Degos disease although antiplatelet drugs,
anticoagulants, and immunosuppressants are utilized to alleviate symptoms.
While the mechanism of Degos disease is unknown, the complement pathway has
been implicated. Margo et al., identified prominent C5b-9 deposits in skin, gastrointestinal
tract and brain vessels of four terminal patients with Degos disease (Margo et al., Am J Clin
Pathol 135(4):599-610, 2011). Experimental treatment with eculizumab was initially
effective in the treatment of skin and intestinal lesions, but did not prevent the progression of
systemic disease (see Garrett-Bakelman F. et al., “C5b-9 is a potential effector in the
pathophysiology of Degos disease; a case report of treatment with eculizumab” (Abstract),
Jerusalem: International Society of Hematology; 2010, Poster #156; and Polito J. et al,
“Early detection of systemic Degos disease (DD) or malignant atrophic papulosis (MAP)
may increase survival” (Abstract), San Antonio, TX: American College of Gastroenterology;
2010, Poster #1205).
Many patients suffering from Degos disease have defects of blood coagulation.
Thrombotic occlusion of small arteries in the skin is characteristic of the disease. Because
the complement pathway is implicated in this disease, as described herein for other TMAs, it
is expected that lectin pathway inhibitors, including but not limited to antibodies that block
MASP-2 function, will be beneficial in treating patients suffering from Degos disease.
Accordingly, in another embodiment, the invention provides methods for treating
Degos disease by administering a composition comprising a therapeutically effective amount
of a MASP-2 inhibitory agent, such as a MASP-2 antibody, in a pharmaceutical carrier to a
subject suffering from Degos disease or a condition resulting from Degos disease. The
MASP-2 inhibitory agent is administered systemically to the subject suffering from Degos
disease or a condition resulting from Degos disease, such as by intra-arterial, intravenous,
intramuscular, inhalational, subcutaneous or other parenteral administration, or potentially by
oral administration for non-peptidergic agents. The anti-MASP-2 antibody may be
administered alone, or in combination with a C5 inhibitor, such as eculizamab.
Catastrophic antiphospholipid syndrome (CAPS)
Catastrophic antiphospholipid syndrome (CAPS) is an extreme variant of the
antiphospholipid syndrome. CAPS is characterized by venous and arterial thrombosis due to
pathogenic antibodies. CAPS is a TMA with multiple organ thrombosis, ischemia, and organ
failure. Like other TMAs, occlusion of small vessels in various organs is characteristic.
There is a high mortality rate in CAPS of about 50% and often it is associated with infection
or trauma. Patients have antiphospholipid antibodies, generally IgG.
Clinically, CAPS involves at least three organs or tissues with histopathological
evidence of small vessel occlusion. Peripheral thrombosis may involve veins and arteries in
the CNS, cardiovascular, renal, or pulmonary systems. Patients are treated with antibiotics,
anticoagulants, corticosteroids, plasma exchange, and intravenous immunoglobulin.
Nevertheless, death may result from multiple organ failure.
The complement pathway has been implicated in CAPS. For example, studies in
animal models indicate that complement inhibition may be an effective means to prevent
thrombosis associated with CAPS (Shapira L. et al., Arthritis Rheum 64(8):2719-23, 2012).
Moreover, as further reported by Shapira et al., administration of eculizumab to a subject
suffering from CAPS at doses that blocked complement pathway aborted acute progressive
thrombotic events and reversed thrombocytopenia (see also Lim W., Curr Opin Hematol
18(5):361-5, 2011). Therefore, as described herein for other TMAs, it is expected that lectin
pathway inhibitors, including but not limited to antibodies that block MASP-2 function, will
be beneficial in treating patients suffering from CAPS.
Accordingly, in another embodiment, the invention provides methods for treating
CAPS by administering a composition comprising a therapeutically effective amount of a
MASP-2 inhibitory agent, such as a MASP-2 antibody, in a pharmaceutical carrier to a
subject suffering from CAPS or a condition resulting from CAPS. The MASP-2 inhibitory
agent is administered systemically to the subject suffering from CAPS or a condition
resulting from CAPS, such as by intra-arterial, intravenous, intramuscular, inhalational,
subcutaneous or other parenteral administration, or potentially by oral administration for
non-peptidergic agents. The anti-MASP-2 antibody may be administered alone, or in
combination with a C5 inhibitor, such as eculizamab.
TMA Secondary to Cancer
Systemic malignancies of any type can lead to clinical and pathologic manifestations
of TMA (see e.g., Batts and Lazarus, Bone Marrow Transplantation 40:709-719, 2007).
Cancer-associated TMA is often found in the lungs and appears to be associated with tumor
emboli (Francis KK et al., Commun Oncol 2:339-43, 2005). Tumor emboli can reduce blood
flow and thus lead to a hypo-perfused state in the affected arterioles and venules. The
resulting tissue stress and injury is expected to activate the lectin pathway of complement in
a localized fashion. The activated lectin pathway in turn can activate the coagulation cascade
via MASP-2 dependent cleavage of prothrombin to thrombin, leading to a pro-thrombotic
state characteristic of TMA. MASP-2 inhibition in this setting is expected to reduce the
localized activation of thrombin and thereby alleviate the pro-thrombotic state.
Therefore, as described herein for other TMAs, it is expected that lectin pathway
inhibitors, including, but not limited to, antibodies that block MASP-2 function, will be
beneficial in treating patients suffering from TMA secondary to cancer.
Accordingly, in another embodiment, the invention provides methods for treating or
preventing TMA secondary to cancer by administering a composition comprising a
therapeutically effective amount of a MASP-2 inhibitory agent, such as a MASP-2 antibody,
in a pharmaceutical carrier to a subject suffering from, or at risk for developing, a TMA
secondary to cancer. The MASP-2 inhibitory agent is administered systemically to the
subject suffering from, or at risk for developing, a TMA secondary to cancer, such as by
intra-arterial, intravenous, intramuscular, inhalational, subcutaneous or other parenteral
administration, or potentially by oral administration for non-peptidergic agents. The antiMASP-2 antibody may be administered alone, or in combination with a C5 inhibitor, such as
eculizamab.
TMA Secondary to Cancer Chemotherapy
Chemotherapy-associated TMA is a condition involving thrombocytopenia,
microangiopathic hemolytic anemia, and renal dysfunction that develops in 2-10% of
patients with a history of malignant neoplasms treated with chemotherapeutic agents such as
gemcytabin, mitomycin, oxaliplatin and others. Chemotherapy–associated TMA is
associated with high mortality poor clinical outcomes (see, e.g., Blake-Haskins et al., Clin
Cancer Res 17(18):5858-5866, 2011).
The etiology of chemotherapy-associated TMA is thought to encompass a nonspecific, toxic insult to the microvascular endothelium. A direct injury to endothelial cells
has been shown in an animal model of mitomycin-induced TMA (Dlott J. et al., Ther Apher
Dial 8:102–11, 2004). Endothelial cell injury through a variety of mechanisms has been
shown to activate the lectin pathway of complement. For example, Stahl et al. have shown
that endothelial cells exposed to oxidative stress activate the lectin pathway of complement
both in vitro and in vivo (Collard et al., Am J Pathol. 156(5):1549-56, 2000; La Bonte et al, J
Immunol. 15;188(2):885-91, 2012). In vivo, this process leads to thombosis, and inhibition
of the lectin pathway has been shown to prevent thrombosis (La Bonte et al. J Immunol.
;188(2):885-91, 2012). Futhermore, as demonstrated in Examples 37-39 herein, in the
mouse model of TMA where localized photoexcitation of FITC-Dex was used to induced
localized injury to the microvasculature with subsequent development of a TMA response,
the present inventors have shown that inhibition of MASP-2 can prevent TMA. Thus,
microvascular endothelium injury by chemotherapeutic agents may activate the lectin
pathway of complement which then creates a localized pro-thrombotic state and promotes a
TMA response. Since activation of the lectin pathway and the creation of a pro-thombotic
state is MASPdependent, it is expected that MASP-2 inhibitors, including, but not limited
to, antibodies that block MASP-2 function, will alleviate the TMA response and reduce the
risk of cancer chemotherapy-associated TMA.
Accordingly, in another embodiment, the invention provides methods for treating or
preventing TMA secondary to chemotherapy by administering a composition comprising a
therapeutically effective amount of a MASP-2 inhibitory agent, such as a MASP-2 antibody,
in a pharmaceutical carrier to a subject suffering from, or at risk for developing, a TMA
secondary to chemotherapy. The MASP-2 inhibitory agent is administered systemically to a
subject that has undergone, is undergoing, or will undergo chemotherapy, such as by
intra-arterial, intravenous, intramuscular, inhalational, subcutaneous or other parenteral
administration, or potentially by oral administration for non-peptidergic agents. The anti-
MASP-2 antibody may be administered alone, or in combination with a C5 inhibitor, such as
eculizamab.
TMA Secondary to Transplantation
Transplantation-associated TMA (TA-TMA) is a devastating syndrome that can
occur in allogeneic hematopoietic stem cell transplant recipients (see e.g., Batts and Lazarus,
Bone Marrow Transplantation 40:709-719, 2007). The pathogenesis of this condition is
poorly understood, but likely involves a confluence of responses that culminate in
endothelial cell injury (Laskin B.L. et al., Blood 118(6):1452-62, 2011). As discussed above,
endothelial cell injury is a prototypic stimulus for lectin pathway activation and the
generation of a pro-thrombotic environment.
Recent data further support the role of complement activation via the lectin pathway
in the pathogenesis TA-TMA. Laskin et al., have demonstrated that renal arteriolar C4d
deposition was much more common in subjects with histologic TA-TMA (75%) compared
with controls (8%) (Laskin B.L., et al., Transplantation, 27; 96(2):217-23, 2013). Thus, C4d
may be a pathologic marker of TA-TMA, implicating localized complement fixation via the
lectin or classical pathway.
Since activation of the lectin pathway and the creation of a pro-thombotic state is
MASPdependent, it is expected that MASP-2 inhibitors, including, but not limited to,
antibodies that block MASP-2 function, will alleviate the TMA response and reduce the risk
of transplantation-associated TMA (TA-TMA).
Accordingly, in another embodiment, the invention provides methods for treating or
preventing a TMA secondary to transplantation by administering a composition comprising a
therapeutically effective amount of a MASP-2 inhibitory agent, such as a MASP-2 antibody,
in a pharmaceutical carrier to a subject suffering from, or at risk for developing a TMA
secondary to transplantation. The MASP-2 inhibitory agent is administered systemically to a
subject that has undergone, is undergoing, or will undergo a transplant procedure, such as by
intra-arterial, intravenous, intramuscular, inhalational, subcutaneous or other parenteral
administration, or potentially by oral administration for non-peptidergic agents. The anti30 MASP-2 antibody may be administered alone, or in combination with a C5 inhibitor, such as
eculizamab.
Cryoglobulinemia and Cold Aggultinin Disease
Another aspect of the invention provides methods for treating Cryoglobulinemia by
administering a composition comprising a therapeutically effective amount of a MASP-2
inhibitory agent in a pharmaceutical carrier to a subject suffering from Cryoglobulinemia or
a condition resulting from Cryoglobulinemia. Cryoglobulinemia is characterized by the
presence of cryoglobulins in the serum, which are single or mixed immmunoglobulins
(typically IgM antibodies) that undergo reversible aggregation at low temperatures.
Conditions resulting from Cryoglobulinemia include vasculitis, glomerulonepthritis, and
systemic inflammation. The MASP-2 inhibitory agent is administered systemically to the
subject suffering from Cryoglobulinemia or a condition resulting from Cryoglobulinemia,
such as by intra-arterial, intravenous, intramuscular, inhalational, subcutaneous or other
parenteral administration, or potentially by oral administration for non-peptidergic agents.
In another aspect, the invention provides methods for treating Cold Agglutinin
disease (CAD) by administering a composition comprising a therapeutically effective amount
of a MASP-2 inhibitory agent in a pharmaceutical carrier to a subject suffering from CAD or
a condition resulting from CAD. CAD disease manifests as anemia and can be caused by an
underlying disease or disorder, referred to as "Secondary CAD" such as an infectious
disease, lymphoproliferative disease or connective tissue disorder. These patients develop
IgM antibodies against their red blood cells that trigger an agglutination reaction at low
temperatures. The MASP-2 inhibitory agent is administered systemically to the subject
suffering from CAD or a condition resulting from CAD, such as by intra-arterial,
intravenous, intramuscular, inhalational, subcutaneous or other parenteral administration, or
potentially by oral administration for non-peptidergic agents.
COAGULOPATHIES
Evidence has been developed for the role of the complement system in disseminated
intravascular coagulation ("DIC"), such as DIC secondary to significant bodily trauma.
Previous studies have shown that C4-/- mice are not protected from renal reperfusion
injury. (Zhou, W., et al, "Predominant role for C5b-9 in renal ischemia/reperfusion injury," J
Clin Invest 105:1363-1371 (2000)) In order to investigate whether C4-/- mice may still be
able to activate complement via either the classical or the lectin pathway, C3 turn-over in C4-
/- plasma was measured in assays specific for either the classical, or the lectin pathway
activation route. While no C3 cleavage could be observed when triggering activation via the
classical, a highly efficient lectin pathway-dependent activation of C3 in C4 deficient serum
was observed (FIGURE 30). It can be seen that C3b deposition on mannan and zymosan is
severely compromised in MASP/- mice, even under experimental conditions, that
according to many previously published papers on alternative pathway activation, should be
permissive for all three pathways. When using the same sera in wells coated with
immunoglobulin complexes instead of mannan or zymosan, C3b deposition and Factor B
cleavage are seen in MASP-2+/+ mouse sera and MASP/- sera, but not in C1q depleted
sera. This indicates that alternate pathway activation is facilitated in MASP/- sera when
the initial C3b is provided via classical activity. FIGURE 30C depicts the surprising finding
that C3 can efficiently be activated in a lectin pathway-dependent fashion in C4 deficient
plasma.
This "C4 bypass" is abolished by the inhibition of lectin pathway-activation through
preincubation of plasma with soluble mannan or mannose.
Aberrant, non-immune, activation of the complement system is potentially hazardous
to man and may also play an important role in hematological pathway activation, particularly
in severe trauma situations wherein both inflammatory and hematological pathways are
activated. In normal health, C3 conversion is <5% of the total plasma C3 protein. In
rampant infection, including septicaemia and immune complex disease, C3 conversion reestablishes itself at about 30% with complement levels frequently lower than normal, due to
increased utilization and changes in pool distribution. Immediate C3 pathway activation of
greater than 30% generally produces obvious clinical evidence of vasodilatation and of fluid
loss to the tissues. Above 30% C3 conversion, the initiating mechanisms are predominantly
non-immune and the resulting clinical manifestations are harmful to the patient.
Complement C5 levels in health and in controlled disease appear much more stable than C3.
Significant decreases and or conversion of C5 levels are associated with the patient's
response to abnormal polytrauma (e.g., road traffic accidents) and the likely development of
shock lung syndromes. Thus, any evidence of either complement C3 activation beyond 30%
of the vascular pool or of any C5 involvement, or both, may be considered likely to be a
harbinger of a harmful pathological change in the patient.
Both C3 and C5 liberate anaphylatoxins (C3a and C5a) that act on mast cells and
basophils releasing vasodilatory chemicals. They set up chemotactic gradients to guide
polymorphonuclear cells (PMN) to the center of immunological disturbances (a beneficial
response), but here they differ because C5a has a specific clumping (aggregating) effect on
these phagocytic cells, preventing their random movement away from the reaction site. In
normal control of infection, C3 activates C5. However, in polytrauma, C5 appears to be
widely activated, generating C5a anaphylatoxins systemically. This uncontrolled activity
causes polymorphs to clump within the vascular system, and these clumps are then swept
into the capillaries of the lungs, which they occlude and generate local damaging effects as a
result of superoxide liberation. While not wishing to be limited by theory, the mechanism is
probably important in the pathogenesis of acute respiratory distress syndrome (ARDS),
although this view has recently been challenged. The C3a anaphylatoxins in vitro can be
shown to be potent platelet aggregators, but their involvement in vivo is less defined and the
release of platelet substances and plasmin in wound repair may only secondarily involve
complement C3. It is possible that prolonged elevation of C3 activation is necessary to
generate DIC.
In addition to cellular and vascular effects of activated complement component
outlined above that could explain the link between trauma and DIC, emerging scientific
discoveries have identified direct molecular links and functional cross-talk between
complement and coagulation systems. Supporting data has been obtained from studies in C3
deficient mice. Because C3 is the shared component for each of the complement pathways,
C3 deficient mice are predicted to lack all complement function. Surprisingly, however, C3
deficient mice are perfectly capable of activating terminal complement components. (HuberLang, M., et al., "Generation of C5a in the absence of C3: a new complement activation
pathway," Nat. Med 12:682-687 (2006)) In depth studies revealed that C3-independent
activation of terminal complement components is mediated by thrombin, the rate limiting
enzyme of the coagulation cascade. (Huber et al., 2006) The molecular components
mediating thrombin activation following initial complement activation remained elusive.
The present inventors have elucidated what is believed to be the molecular basis for
cross-talk between complement and clotting cascades and identified MASP-2 as a central
control point linking the two systems. Biochemical studies into the substrate specificity of
MASP-2 have identified prothrombin as a possible substrate, in addition to the well known
C2 and C4 complement proteins. MASP-2 specifically cleaves prothrombin at functionally
relevant sites, generating thrombin, the rate limiting enzyme of the coagulation cascade.
(Krarup, A., et al., "Simultaneous Activation of Complement and Coagulation by MBLAssociated Serine Protease 2," PLoS. ONE. 2:e623 (2007)) MASPgenerated thrombin is
capable of promoting fibrin deposition in a defined reconstituted in vitro system,
demonstrating the functional relevance of MASP-2 cleavage. (Krarup et al., 2007) As
discussed in the examples herein below, the inventors have further corroborated the
physiological significance of this discovery by documenting thrombin activation in normal
rodent serum following lectin pathway activation, and demonstrated that this process is
blocked by neutralizing MASP-2 monoclonal antibodies.
MASP-2 may represent a central branch point in the lectin pathway, capable of
promoting activation of both complement and coagulation systems. Because lectin pathway
activation is a physiologic response to many types of traumatic injury, the present inventors
believe that concurrent systemic inflammation (mediated by complement components) and
disseminated coagulation (mediated via the clotting pathway) can be explained by the
capacity of MASP-2 to activate both pathways. These findings clearly suggest a role for
MASP-2 in DIC generation and therapeutic benefit of MASP-2 inhibition in treating or
preventing DIC. MASP-2 may provide the molecular link between complement and
coagulation system, and activation of the lectin pathway as it occurs in settings of trauma can
directly initiate activation of the clotting system via the MASPthrombin axis, providing a
mechanistic link between trauma and DIC. In accordance with an aspect of the present
invention, inhibition of MASP-2 would inhibit lectin pathway activation and reduce the
generation of both anaphylatoxins C3a and C5a. It is believed that prolonged elevation of C3
activation is necessary to generate DIC.
Therefore, an aspect of the invention thus provides a method for inhibiting
MASPdependent complement activation to treat disseminated intravascular coagulation or
other complement mediated coagulation disorder by administering a composition comprising
a therapeutically effective amount of a MASP-2 inhibitory agent (e.g., anti-MASP-2
antibody or fragment thereof, peptide inhibitors or small molecule inhibitors) in a
pharmaceutical carrier to a subject suffering from or at risk for developing such a condition.
In some embodiments, the MASP-2 inhibitory agents can block MASP-2 that has already
been activated. The MASP-2 inhibitory composition is suitably administered to the subject
systemically, such as by intra-arterial, intravenous, intramuscular, inhalational, nasal,
subcutaneous or other parenteral administration, or potentially by oral administration for
non-peptidergic agents. Administration may be repeated as determined by a physician until
the condition has been resolved or is controlled. The methods of this aspect of the present
invention may be utilized for treatment of DIC secondary to sepsis, severe trauma, including
neurological trauma (e.g., acute head injury, see Kumura, E., et al., Acta Neurochirurgica
85:23-28 (1987), infection (bacterial, viral, fungal, parasitic), cancer, obstetrical
complications, liver disease, severe toxic reaction (e.g., snake bite, insect bite, transfusion
reaction), shock, heat stroke, transplant rejection, vascular aneurysm, hepatic failure, cancer
treatment by chemotherapy or radiation therapy, burn, accidental radiation exposure, and
other causes. See e.g., Becker J.U. and Wira C.R. "Disseminated Intravascular Coagulation"
emedicine.medscape.com/9/10/2009. For DIC secondary to trauma or other acute event, the
MASP-2 inhibitory composition may be administered immediately following the traumatic
injury or prophylactically prior to, during, immediately following, or within one to seven
days or longer, such as within 24 hours to 72 hours, after trauma-inducing injury or situations
such as surgery in patients deemed at risk of DIC. In some embodiments, the MASP-2
inhibitory composition may suitably be administered in a fast-acting dosage form, such as by
intravenous or intra-arterial delivery of a bolus of a solution containing the MASP-2
inhibitory agent composition.
In another aspect, the present invention provides methods of treating a subject
suffering from or at risk for developing thrombosis, microcirculatory coagulation or multiorgan failure subsequent to microcirculatory coagulation. Physiological thrombus (blood
clot) forms in response to vascular insult to prevent leakage of blood from a damaged blood
vessel.
The lectin pathway may play a role in pathological thrombosis triggered by an
underlying vascular inflammation linked to various etiologies. For example, a thrombus can
form around atherosclerotic plaques, which is a known initiator of the lectin pathway. Thus,
treatment with a MASP-2 inhibitor may be used to block thrombus formation in patients with
underlying atheroscelorsis.
Microcirculatory coagulation (blot clots in capillaries and small blood vessels) occurs
in settings such a septic shock. A role of the lectin pathway in septic shock is established, as
evidenced by the protected phenotype of MASP-2 (-/-) mouse models of sepsis, described in
Example 17 and FIGURES 18 and 19. Furthermore, as demonstrated in Example 15 and
FIGURES 16A and 16B, MASP-2 (-/-) mice are protected in the localized Schwartzman
reaction model of disseminated intravascular coagulation (DIC), a model of localized
coagulation in microvessels.
PERICHEMOTHERAPEUTIC ADMINISTRATION AND TREATMENT OF
MALIGNANCIES
Activation of the complement system may also be implicated in the pathogenesis of
malignancies. Recently, the neoantigens of the C5b-9 complement complex, IgG, C3, C4,
S-protein/vitronectin, fibronectin, and macrophages were localized on 17 samples of breast
cancer and on 6 samples of benign breast tumors using polyclonal or monoclonal antibodies
and the streptavidin-biotin-peroxidase technique. All the tissue samples with carcinoma in
each the TNM stages presented C5b-9 deposits on the membranes of tumor cells, thin
granules on cell remnants, and diffuse deposits in the necrotic areas (Niculescu, F., et al.,
Am. J. Pathol. 140:1039-1043, 1992).
In addition, complement activation may be a consequence of chemotherapy or
radiation therapy and thus inhibition of complement activation would be useful as an adjunct
in the treatment of malignancies to reduce iatrogenic inflammation. When chemotherapy
and radiation therapy preceded surgery, C5b-9 deposits were more intense and extended.
The C5b-9 deposits were absent in all the samples with benign lesions. S-protein/vitronectin
was present as fibrillar deposits in the connective tissue matrix and as diffuse deposits around
the tumor cells, less intense and extended than fibronectin. IgG, C3, and C4 deposits were
present only in carcinoma samples. The presence of C5b-9 deposits is indicative of
complement activation and its subsequent pathogenetic effects in breast cancer (Niculescu,
F., et al., Am. J. Pathol. 140:1039-1043, 1992).
Pulsed tunable dye laser (577 nm) (PTDL) therapy induces hemoglobin coagulation
and tissue necrosis, which is mainly limited to blood vessels. In a PTDL-irradiated normal
skin study, the main findings were as follows: 1) C3 fragments, C8, C9, and MAC were
deposited in vessel walls; 2) these deposits were not due to denaturation of the proteins since
they became apparent only 7 min after irradiation, contrary to immediate deposition of
transferrin at the sites of erythrocyte coagulates; 3) the C3 deposits were shown to amplify
complement activation by the alternative pathway, a reaction which was specific since tissue
necrosis itself did not lead to such amplification; and 4) these reactions preceded the local
accumulation of polymorphonuclear leucocytes. Tissue necrosis was more pronounced in
the hemangiomas. The larger angiomatous vessels in the center of the necrosis did not fix
complement significantly. By contrast, complement deposition in the vessels situated at the
periphery was similar to that observed in normal skin with one exception: C8, C9, and MAC
were detected in some blood vessels immediately after laser treatment, a finding consistent
with assembly of the MAC occurring directly without the formation of a C5 convertase.
These results indicate that complement is activated in PTDL-induced vascular necrosis, and
might be responsible for the ensuing inflammatory response.
Photodynamic therapy (PDT) of tumors elicits a strong host immune response, and
one of its manifestations is a pronounced neutrophilia. In addition to complement fragments
(direct mediators) released as a consequence of PDT-induced complement activation, there
are at least a dozen secondary mediators that all arise as a result of complement activity. The
latter include cytokines IL-1beta, TNF-alpha, IL-6, IL-10, G-CSF and KC, thromboxane,
prostaglandins, leukotrienes, histamine, and coagulation factors (Cecic, I., et al., Cancer
Lett. 183:43-51, 2002).
Finally, the use of inhibitors of MASPdependent complement activation may be
envisioned in conjunction with the standard therapeutic regimen for the treatment of cancer.
For example, treatment with rituximab, a chimeric anti-CD20 monoclonal antibody, can be
associated with moderate to severe first-dose side-effects, notably in patients with high
numbers of circulating tumor cells. Recent studies during the first infusion of rituximab
measured complement activation products (C3b/c and C4b/c) and cytokines (tumour necrosis
factor alpha (TNF-alpha), interleukin 6 (IL-6) and IL-8) in five relapsed low-grade
non-Hodgkin's lymphoma (NHL) patients. Infusion of rituximab induced rapid complement
activation, preceding the release of TNF-alpha, IL-6 and IL-8. Although the study group was
small, the level of complement activation appeared to be correlated both with the number of
circulating B cells prior to the infusion (r = 0.85; P = 0.07), and with the severity of the
side-effects. The results indicated that complement plays a pivotal role in the pathogenesis
of side-effects of rituximab treatment. As complement activation cannot be prevented by
corticosteroids, it may be relevant to study the possible role of complement inhibitors during
the first administration of rituximab (van der Kolk, L.E., et al., Br. J.
Haematol. 115:807-811, 2001).
In another aspect of the invention, methods are provided for inhibiting
MASPdependent complement activation in a subject being treated with chemotherapeutics
and/or radiation therapy, including without limitation for the treatment of cancerous
conditions. This method includes administering a composition comprising a therapeutically
effective amount of a MASP-2 inhibitor in a pharmaceutical carrier to a patient
perichemotherapeutically, i.e., before and/or during and/or after the administration of
chemotherapeutic(s) and/or radiation therapy. For example, administration of a MASP-2
inhibitor composition of the present invention may be commenced before or concurrently
with the administration of chemo- or radiation therapy, and continued throughout the course
of therapy, to reduce the detrimental effects of the chemo- and/or radiation therapy in the
non-targeted, healthy tissues. In addition, the MASP-2 inhibitor composition can be
administered following chemo- and/or radiation therapy. It is understood that chemo- and
radiation therapy regimens often entail repeated treatments and, therefore, it is possible that
administration of a MASP-2 inhibitor composition would also be repetitive and relatively
coincident with the chemotherapeutic and radiation treatments. It is also believed that
MASP-2 inhibitory agents may be used as chemotherapeutic agents, alone or in combination
with other chemotherapeutic agents and/or radiation therapy, to treat patients suffering from
malignancies. Administration may suitably be via oral (for non-peptidergic), intravenous,
intramuscular or other parenteral route.
In another embodiment, MASP-2 inhibitory agents may be used to treat a subject for
acute radiation syndrome (also known as radiation sickness or radiation poisoning) to reduce
the detrimental effects of exposure to ionizing radiation (accidental or otherwise).
Symptoms associated with acute radiation syndrome include nausea, vomiting, diarrhea, skin
damage, hair loss, fatigue, fever, seizures and coma. For treatment of acute radiation
syndrome, the MASP-2 inhibitory composition may be administered immediately following
the radiation exposure or prophylactically prior to, during, immediately following, or within
one to seven days or longer, such as within 24 hours to 72 hours, after exposure. In some
embodiments, the methods may be used to treat a subject prior to or after exposure to a
dosage of ionizing radiation sufficient to cause acute radiation syndrome (i.e. a whole body
dosage of ionizing radiation of at least 1 Gy, or at least 2 Gy, or at least 3 Gy, or at least 4
Gy, or at least 5 Gy, or at least 6 Gy, or at least 7 Gy, or higher). In some embodiments, the
MASP-2 inhibitory composition may suitably be administered in a fast-acting dosage form,
such as by intravenous or intra-arterial delivery of a bolus of a solution containing the
MASP-2 inhibitory agent composition.
OPHTHALMOLOGIC CONDITIONS
Age-related macular degeneration (AMD) is a blinding disease that afflicts millions
of adults, yet the sequelae of biochemical, cellular, and/or molecular events leading to the
development of AMD are poorly understood. AMD results in the progressive destruction of
the macula which has been correlated with the formation of extracellular deposits called
drusen located in and around the macula, behind the retina and between the retina pigment
epithelium (RPE) and the choroid. Recent studies have revealed that proteins associated with
inflammation and immune-mediated processes are prevalent among drusen-associated
constituents. Transcripts that encode a number of these molecules have been detected in
retinal, RPE, and choroidal cells. These data also demonstrate that dendritic cells, which are
potent antigen-presenting cells, are intimately associated with drusen development, and that
complement activation is a key pathway that is active both within drusen and along the
RPE-choroid interface (Hageman, G.S., et al., Prog. Retin. Eye Res. 20:705-732, 2001).
Several independent studies have shown a strong association between AMD and a
genetic polymorphism in the gene for complement factor H (CFH) in which the likelihood of
AMD is increased by a factor of 7.4 in individuals homozygous for the risk allele (Klein,
R.J. et al., Science 308:362-364, 2005; Haines et al., Science 308:362-364. 2005; Edwards
et al., Science 308:263-264, 2005). The CFH gene has been mapped to chromosome 1q31 a
region that had been implicated in AMD by six independent linkage scans (see, e.g., Schultz,
D.W., et al., Hum. Mol. Genet. 12:3315, 2003). CFH is known to be a key regulator of the
complement system. It has been shown that CFH on cells and in circulation regulates
complement activity by inhibiting the activation of C3 to C3a and C3b, and by inactivating
existing C3b. Deposition of C5b-9 has been observed in Brusch's membrane, the
intercapillary pillars and within drusen in patients with AMD (Klein et al.).
Immunofluorescence experiments suggest that in AMD, the polymorphism of CFH may give
rise to complement deposition in chorodial capillaries and chorodial vessels (Klein et al.).
The membrane-associated complement inhibitor, complement receptor 1, is also
localized in drusen, but it is not detected in RPE cells immunohistochemically. In contrast, a
second membrane-associated complement inhibitor, membrane cofactor protein, is present in
drusen-associated RPE cells, as well as in small, spherical substructural elements within
drusen. These previously unidentified elements also show strong immunoreactivity for
proteolytic fragments of complement component C3 that are characteristically deposited at
sites of complement activation. It is proposed that these structures represent residual debris
from degenerating RPE cells that are the targets of complement attack (Johnson, L.V., et al.,
Exp. Eye Res. 73:887-896, 2001).
Identification and localization of these multiple complement regulators as well as
complement activation products (C3a, C5a, C3b, C5b-9) have led investigators to conclude
that chronic complement activation plays an important role in the process of drusen
biogenesis and the etiology of AMD (Hageman et al., Progress Retinal Eye Res. 20:705-32,
2001). Identification of C3 and C5 activation products in drusen provides no insight into
whether complement is activated via the classical pathway, the lectin pathway or the
alternative amplification loop, as understood in accordance with the present invention, since
both C3 and C5 are common to all three. However, two studies have looked for drusen
immuno-labeling using antibodies specific to C1q, the essential recognition component for
activation of the classical pathway (Mullins et al., FASEB J. 14:835-846, 2000; Johnson
et al., Exp. Eye Res. 70:441-449, 2000). Both studies concluded that C1q immuno-labelling
in drusen was not generally observed. These negative results with C1q suggest that
complement activation in drusen does not occur via the classical pathway. In addition,
immuno-labeling of drusen for immune-complex constituents (IgG light chains, IgM) is
reported in the Mullins et al., 2000 study as being weak to variable, further indicating that the
classical pathway plays a minor role in the complement activation that occurs in this disease
process.
Two recent published studies have evaluated the role of complement in the
development of laser-induced choroidal neovascularization (CNV) in mice, a model of
human CNV. Using immunohistological methods, Bora and colleagues (2005) found
significant deposition of the complement activation products C3b and C5b-9 (MAC) in the
neovascular complex following laser treatment (Bora et al., J. Immunol. 174:491-7, 2005).
Importantly, CNV did not develop in mice genetically deficient in C3 (C3-/- mice), the
essential component required in all complement activation pathways. RNA message levels
for VEGF, TGF-β2, and β-FGF, three angiogenic factors implicated in CNV, were elevated
in eye tissue from mice after laser-induced CNV. Significantly, complement depletion
resulted in a marked reduction in the RNA levels of these angiogenic factors.
Using ELISA methods, Nozaki and colleagues demonstrated that the potent
anaphylatoxins C3a and C5a are generated early in the course of laser-induced CNV (Nozaki
et al., Proc. Natl. Acad. Sci. U.S.A. 103:2328-33, 2006). Furthermore, these two bioactive
fragments of C3 and C5 induced VEGF expression following intravitreal injection in
wild-type mice. Consistent with these results Nozaki and colleagues also showed that
genetic ablation of receptors for C3a and C5a reduces VEGF expression and CNV formation
after laser injury, and that antibody-mediated neutralization of C3a or C5a or pharmacologic
blockade of their receptors also reduces CNV. Previous studies have established that
recruitment of leukocytes, and macrophages in particular, plays a pivotal role in
laser-induced CNV (Sakurai et al., Invest. Opthomol. Vis. Sci. 44:3578-85, 2003;
Espinosa-Heidmann, et al., Invest. Opthomol. Vis. Sci. 44:3586-92, 2003). In their 2006
paper, Nozaki and colleagues report that leukocyte recruitment is markedly reduced in
C3aR(-/-) and C5aR(-/-) mice after laser injury.
An aspect of the invention thus provides a method for inhibiting MASPdependent
complement activation to treat age-related macular degeneration or other complement
mediated ophthalmologic condition by administering a composition comprising a
therapeutically effective amount of a MASP-2 inhibitory agent in a pharmaceutical carrier to
a subject suffering from such a condition or other complement-mediated ophthalmologic
condition. The MASP-2 inhibitory composition may be administered locally to the eye, such
as by irrigation or application of the composition in the form of a gel, salve or drops.
Alternately, the MASP-2 inhibitory agent may be administered to the subject systemically,
such as by intra-arterial, intravenous, intramuscular, inhalational, nasal, subcutaneous or
other parenteral administration, or potentially by oral administration for non-peptidergic
agents. The MASP-2 inhibitory agent composition may be combined with one or more
additional therapeutic agents, such as are disclosed in U.S. Patent Application Publication
No. 2004A1. Administration may be repeated as determined by a physician until
the condition has been resolved or is controlled.
In another aspect, the invention provides a method for inhibiting MASPdependent
complement activation to treat a subject suffering from or at risk for developing glaucoma. It
has been shown that uncontrolled complement activation contributes to the progression of
degenerative injury to retinal ganglion cells (RGCs), their synapses and axons in glaucoma.
See Tezel G. et al., Invest Ophthalmol Vis Sci 51:5071-5082 (2010). For example,
histopathologic studies of human tissues and in vivo studies using different animal models
have demonstrated that complement components, including C1q and C3, are synthesized and
terminal complement complex is formed in the glaucomatous retina (see Stasi K. et al.,
Invest Ophthalmol Vis Sci 47:1024-1029 (2006), Kuehn M.H. et al., Exp Eye Res 83:620-628
(2006)). As described in Tezel G. et al., it has been determined that in addition to the
classical pathway, the lectin pathway is likely to be involved in complement activation
during glaucomatous neurodegeneration, thereby facilitating the progression of
neurodegenerative injury by collateral cell lysis, inflammation and autoimmunity. As
described in Tezel G. et al., proteomic analysis of human retinal samples obtained from
donor eyes with or without glaucoma detected the expression and differential regulation of
several complement components. Notably, expression levels of complement components
from the lectin pathway were higher, or only detected, in glaucomatous samples than
controls, including MASP-1 and MASP-2, and C-type lectin. As further described in Kuehn
M.H. et al., Experimental Eye Research 87:89-95 (2008), complement synthesis and
deposition is induced by retinal I/R and the disruption of the complement cascade delays
RGC degeneration. In this study, mice carrying a targeted disruption of the complement
component C3 were found to exhibit delayed RGC degeneration after transient retinal I/R
when compared to normal animals.
The findings of these studies suggest that alterations in the physiological balance
between complement activation and intrinsic regulation under glaucomatous stress consitions
may have an important impact on the progression of neurodegenerative injury, indicating that
inhibition of complement activation, such as through the administration of anti-MASP-2
antibodies, can be used as a therapeutic for glaucoma patients.
An aspect of the invention thus provides a method for inhibiting MASPdependent
complement activation to treat glaucoma by administering a composition comprising a
therapeutically effective amount of a MASP-2 inhibitory agent in a pharmaceutical carrier to
a subject suffering from glaucoma. The MASP-2 inhibitory composition may be
administered locally to the eye, such as by irrigation or application of the composition in the
form of a gel, salve or drops. Alternately, the MASP-2 inhibitory agent may be administered
to the subject systemically, such as by intra-arterial, intravenous, intramuscular, inhalational,
nasal, subcutaneous or other parenteral administration, or potentially by oral administration
for non-peptidergic agents. Administration may be repeated as determined by a physician
until the condition has been resolved or is controlled.
IV. MASP-2 INHIBITORY AGENTS
In one aspect, the present invention provides methods of inhibiting the adverse effects
of MASPdependent complement activation. MASP-2 inhibitory agents are administered
in an amount effective to inhibit MASPdependent complement activation in a living
subject. In the practice of this aspect of the invention, representative MASP-2 inhibitory
agents include: molecules that inhibit the biological activity of MASP-2 (such as small
molecule inhibitors, anti-MASP-2 antibodies or blocking peptides which interact with
MASP-2 or interfere with a protein-protein interaction), and molecules that decrease the
expression of MASP-2 (such as MASP-2 antisense nucleic acid molecules, MASP-2 specific
RNAi molecules and MASP-2 ribozymes), thereby preventing MASP-2 from activating the
lectin complement pathway. The MASP-2 inhibitory agents can be used alone as a primary
therapy or in combination with other therapeutics as an adjuvant therapy to enhance the
therapeutic benefits of other medical treatments.
The inhibition of MASPdependent complement activation is characterized by at
least one of the following changes in a component of the complement system that occurs as a
result of administration of a MASP-2 inhibitory agent in accordance with the methods of the
invention: the inhibition of the generation or production of MASPdependent complement
activation system products C4b, C3a, C5a and/or C5b-9 (MAC) (measured, for example, as
described in Example 2), the reduction of complement activation assessed in a hemolytic
assay using unsensitized rabbit or guinea pig red blood cells (measured, for example as
described in Example 33), the reduction of C4 cleavage and C4b deposition (measured, for
example as described in Example 2), or the reduction of C3 cleavage and C3b deposition
(measured, for example, as described in Example 2).
According to the present invention, MASP-2 inhibitory agents are utilized that are
effective in inhibiting the MASPdependent complement activation system. MASP-2
inhibitory agents useful in the practice of this aspect of the invention include, for example,
anti-MASP-2 antibodies and fragments thereof, MASP-2 inhibitory peptides, small
molecules, MASP-2 soluble receptors and expression inhibitors. MASP-2 inhibitory agents
may inhibit the MASPdependent complement activation system by blocking the biological
function of MASP-2. For example, an inhibitory agent may effectively block MASP-2
protein-to-protein interactions, interfere with MASP-2 dimerization or assembly, block Ca2+
binding, interfere with the MASP-2 serine protease active site, or may reduce MASP-2
protein expression.
In some embodiments, the MASP-2 inhibitory agents selectively inhibit MASP-2
complement activation, leaving the C1q-dependent complement activation system
functionally intact.
In one embodiment, a MASP-2 inhibitory agent useful in the methods of the
invention is a specific MASP-2 inhibitory agent that specifically binds to a polypeptide
comprising SEQ ID NO:6 with an affinity of at least ten times greater than to other antigens
in the complement system. In another embodiment, a MASP-2 inhibitory agent specifically
binds to a polypeptide comprising SEQ ID NO:6 with a binding affinity of at least 100 times
greater than to other antigens in the complement system. The binding affinity of the
MASP-2 inhibitory agent can be determined using a suitable binding assay.
The MASP-2 polypeptide exhibits a molecular structure similar to MASP-1,
MASP-3, and C1r and C1s, the proteases of the C1 complement system. The cDNA
molecule set forth in SEQ ID NO:4 encodes a representative example of MASP-2 (consisting
of the amino acid sequence set forth in SEQ ID NO:5) and provides the human MASP-2
polypeptide with a leader sequence (aa 1-15) that is cleaved after secretion, resulting in the
mature form of human MASP-2 (SEQ ID NO:6). As shown in FIGURE 2, the human
MASP 2 gene encompasses twelve exons. The human MASP-2 cDNA is encoded by exons
B, C, D, F, G, H, I, J, K AND L. An alternative splice results in a 20 kDa protein termed
MBL-associated protein 19 ("MAp19", also referred to as "sMAP") (SEQ ID NO:2),
encoded by (SEQ ID NO:1) arising from exons B, C, D and E as shown in FIGURE 2. The
cDNA molecule set forth in SEQ ID NO:50 encodes the murine MASP-2 (consisting of the
amino acid sequence set forth in SEQ ID NO:51) and provides the murine MASP-2
polypeptide with a leader sequence that is cleaved after secretion, resulting in the mature
form of murine MASP-2 (SEQ ID NO:52). The cDNA molecule set forth in SEQ ID NO:53
encodes the rat MASP-2 (consisting of the amino acid sequence set forth in SEQ ID NO:54)
and provides the rat MASP-2 polypeptide with a leader sequence that is cleaved after
secretion, resulting in the mature form of rat MASP-2 (SEQ ID NO:55).
Those skilled in the art will recognize that the sequences disclosed in SEQ ID NO:4,
SEQ ID NO:50 and SEQ ID NO:53 represent single alleles of human, murine and rat
MASP-2 respectively, and that allelic variation and alternative splicing are expected to occur.
Allelic variants of the nucleotide sequences shown in SEQ ID NO:4, SEQ ID NO:50 and
SEQ ID NO:53, including those containing silent mutations and those in which mutations
result in amino acid sequence changes, are within the scope of the present invention. Allelic
variants of the MASP-2 sequence can be cloned by probing cDNA or genomic libraries from
different individuals according to standard procedures.
The domains of the human MASP-2 protein (SEQ ID NO:6) are shown in FIGURE 1
and 2A and include an N-terminal C1r/C1s/sea urchin Vegf/bone morphogenic protein
(CUBI) domain (aa 1-121 of SEQ ID NO:6), an epidermal growth factor-like domain
(aa 122-166), a second CUBI domain (aa 167-293), as well as a tandem of complement
control protein domains and a serine protease domain. Alternative splicing of the MASP 2
gene results in MAp19 shown in FIGURE 1. MAp19 is a nonenzymatic protein containing
the N-terminal CUB1-EGF region of MASP-2 with four additional residues (EQSL) derived
from exon E as shown in FIGURE 1.
Several proteins have been shown to bind to, or interact with MASP-2 through
protein-to-protein interactions. For example, MASP-2 is known to bind to, and form Ca2+
dependent complexes with, the lectin proteins MBL, H-ficolin and L-ficolin. Each
MASP-2/lectin complex has been shown to activate complement through the
MASPdependent cleavage of proteins C4 and C2 (Ikeda, K., et al., J. Biol.
Chem. 262:7451-7454, 1987; Matsushita, M., et al., J. Exp. Med. 176:1497-2284, 2000;
Matsushita, M., et al., J. Immunol. 168:3502-3506, 2002). Studies have shown that the
CUB1-EGF domains of MASP-2 are essential for the association of MASP-2 with MBL
(Thielens, N.M., et al., J. Immunol. 166:5068, 2001). It has also been shown that the
CUB1EGFCUBII domains mediate dimerization of MASP-2, which is required for
formation of an active MBL complex (Wallis, R., et al., J. Biol. Chem. 275:30962-30969,
2000). Therefore, MASP-2 inhibitory agents can be identified that bind to or interfere with
MASP-2 target regions known to be important for MASPdependent complement
activation.
ANTI-MASP-2 ANTIBODIES
In some embodiments of this aspect of the invention, the MASP-2 inhibitory agent
comprises an anti-MASP-2 antibody that inhibits the MASPdependent complement
activation system. The anti-MASP-2 antibodies useful in this aspect of the invention include
polyclonal, monoclonal or recombinant antibodies derived from any antibody producing
mammal and may be multispecific, chimeric, humanized, anti-idiotype, and antibody
fragments. Antibody fragments include Fab, Fab', F(ab)2, F(ab')2, Fv fragments, scFv
fragments and single-chain antibodies as further described herein.
Several anti-MASP-2 antibodies have been described in the literature, some of which
are listed below in TABLE 1. These previously described anti-MASP-2 antibodies can be
screened for the ability to inhibit the MASPdependent complement activation system
using the assays described herein. For example, anti rat MASP-2 Fab2 antibodies have been
identified that block MASP-2 dependent complement activation, as described in more detail
in Examples 10 and 11 herein. Once an anti-MASP-2 antibody is identified that functions as
a MASP-2 inhibitory agent, it can be used to produce anti-idiotype antibodies and used to
identify other MASP-2 binding molecules as further described below.
TABLE 1: MASP-2 SPECIFIC ANTIBODIES FROM THE LITERATURE
ANTIGEN ANTIBODY TYPE REFERENCE
Recombinant
MASP-2
Rat Polyclonal Peterson, S.V., et al., Mol.
Immunol. 37:803-811, 2000
Recombinant human
CCP1/2-SP fragment
(MoAb 8B5)
Rat MoAb
(subclass IgG1)
Moller-Kristensen, M., et al., J. of
Immunol. Methods 282:159-167,
2003
Recombinant human
MAp19 (MoAb
6G12) (cross reacts
with MASP-2)
Rat MoAb
(subclass IgG1)
Moller-Kristensen, M., et al., J. of
Immunol. Methods 282:159-167,
2003
hMASP-2 Mouse MoAb (S/P)
Mouse MoAb (N-term)
Peterson, S.V., et al., Mol.
Immunol. 35:409, April 1998
hMASP-2
(CCP1-CCP2-SP
domain
rat MoAb: Nimoab101,
produced by hybridoma
cell line 03050904
(ECACC)
hMASP-2 (full
length-his tagged)
murine MoAbs:
NimoAb104, produced
by hybridoma cell line
M0545YM035 (DSMZ)
NimoAb108, produced
by hybridoma cell line
M0545YM029 (DSMZ)
NimoAb109 produced
by hybridoma cell line
M0545YM046 (DSMZ)
NimoAb110 produced
by hybridoma cell line
M0545YM048 (DSMZ)
ANTI-MASP-2 ANTIBODIES WITH REDUCED EFFECTOR FUNCTION
In some embodiments of this aspect of the invention, the anti-MASP-2 antibodies
have reduced effector function in order to reduce inflammation that may arise from the
activation of the classical complement pathway. The ability of IgG molecules to trigger the
classical complement pathway has been shown to reside within the Fc portion of the
molecule (Duncan, A.R., et al., Nature 332:738-740 1988). IgG molecules in which the Fc
portion of the molecule has been removed by enzymatic cleavage are devoid of this effector
function (see Harlow, Antibodies: A Laboratory Manual, Cold Spring Harbor Laboratory,
New York, 1988). Accordingly, antibodies with reduced effector function can be generated
as the result of lacking the Fc portion of the molecule by having a genetically engineered Fc
sequence that minimizes effector function, or being of either the human IgG2 or IgG4
isotype.
Antibodies with reduced effector function can be produced by standard molecular
biological manipulation of the Fc portion of the IgG heavy chains as described in Example 9
herein and also described in Jolliffe et al., Int'l Rev. Immunol. 10:241-250, 1993, and
Rodrigues et al., J. Immunol. 151:6954-6961, 1998. Antibodies with reduced effector
function also include human IgG2 and IgG4 isotypes that have a reduced ability to activate
complement and/or interact with Fc receptors (Ravetch, J.V., et al., Annu. Rev.
Immunol. 9:457-492, 1991; Isaacs, J.D., et al., J. Immunol. 148:3062-3071, 1992; van de
Winkel, J.G., et al., Immunol. Today 14:215-221, 1993). Humanized or fully human
antibodies specific to human MASP-2 comprised of IgG2 or IgG4 isotypes can be produced
by one of several methods known to one of ordinary skilled in the art, as described in
Vaughan, T.J., et al., Nature Biotechnical 16:535-539, 1998.
PRODUCTION OF ANTI-MASP-2 ANTIBODIES
Anti-MASP-2 antibodies can be produced using MASP-2 polypeptides (e.g., full
length MASP-2) or using antigenic MASP-2 epitope-bearing peptides (e.g., a portion of the
MASP-2 polypeptide). Immunogenic peptides may be as small as five amino acid residues.
For example, the MASP-2 polypeptide including the entire amino acid sequence of SEQ ID
NO:6 may be used to induce anti-MASP-2 antibodies useful in the method of the invention.
Particular MASP-2 domains known to be involved in protein-protein interactions, such as the
CUBI, and CUBIEGF domains, as well as the region encompassing the serine-protease
active site, may be expressed as recombinant polypeptides as described in Example 3 and
used as antigens. In addition, peptides comprising a portion of at least 6 amino acids of the
MASP-2 polypeptide (SEQ ID NO:6) are also useful to induce MASP-2 antibodies.
Additional examples of MASP-2 derived antigens useful to induce MASP-2 antibodies are
provided below in TABLE 2. The MASP-2 peptides and polypeptides used to raise
antibodies may be isolated as natural polypeptides, or recombinant or synthetic peptides and
catalytically inactive recombinant polypeptides, such as MASP-2A, as further described in
Examples 5-7. In some embodiments of this aspect of the invention, anti-MASP-2
antibodies are obtained using a transgenic mouse strain as described in Examples 8 and 9 and
further described below.
Antigens useful for producing anti-MASP-2 antibodies also include fusion
polypeptides, such as fusions of MASP-2 or a portion thereof with an immunoglobulin
polypeptide or with maltose-binding protein. The polypeptide immunogen may be a
full-length molecule or a portion thereof. If the polypeptide portion is hapten-like, such
portion may be advantageously joined or linked to a macromolecular carrier (such as keyhole
limpet hemocyanin (KLH), bovine serum albumin (BSA) or tetanus toxoid) for
immunization.
TABLE 2: MASP-2 DERIVED ANTIGENS
SEQ ID NO: Amino Acid Sequence
SEQ ID NO:6 Human MASP-2 protein
SEQ ID NO:51 Murine MASP-2 protein
SEQ ID NO:8 CUBI domain of human MASP-2
(aa 1-121 of SEQ ID NO:6)
SEQ ID NO:9 CUBIEGF domains of human MASP-2
(aa 1-166 of SEQ ID NO:6)
SEQ ID NO:10 CUBIEGFCUBII domains of human MASP-2
(aa 1-293 of SEQ ID NO:6)
SEQ ID NO:11 EGF domain of human MASP-2
(aa 122-166 of SEQ ID NO:6)
SEQ ID NO:12 Serine-Protease domain of human MASP-2
(aa 429-671 of SEQ ID NO:6)
SEQ ID NO:13
GKDSCRGDAGGALVFL
Serine-Protease inactivated mutant form
(aa 610-625 of SEQ ID NO:6 with mutated Ser 618)
SEQ ID NO:14
TPLGPKWPEPVFGRL
Human CUBI peptide
SEQ ID NO: Amino Acid Sequence
SEQ ID NO:15:
TAPPGYRLRLYFTHFDLEL
SHLCEYDFVKLSSGAKVL
ATLCGQ
Human CUBI peptide
SEQ ID NO:16:
TFRSDYSN
MBL binding region in human CUBI domain
SEQ ID NO:17:
FYSLGSSLDITFRSDYSNEK
PFTGF
MBL binding region in human CUBI domain
SEQ ID NO:18
IDECQVAPG
EGF peptide
SEQ ID NO:19
ANMLCAGLESGGKDSCRG
DSGGALV
Peptide from serine-protease active site
POLYCLONAL ANTIBODIES
Polyclonal antibodies against MASP-2 can be prepared by immunizing an animal
with MASP-2 polypeptide or an immunogenic portion thereof using methods well known to
those of ordinary skill in the art. See, for example, Green et al., "Production of Polyclonal
Antisera," in Immunochemical Protocols (Manson, ed.), page 105, and as further described in
Example 6. The immunogenicity of a MASP-2 polypeptide can be increased through the use
of an adjuvant, including mineral gels, such as aluminum hydroxide or Freund's adjuvant
(complete or incomplete), surface active substances such as lysolecithin, pluronic polyols,
polyanions, oil emulsions, keyhole limpet hemocyanin and dinitrophenol. Polyclonal
antibodies are typically raised in animals such as horses, cows, dogs, chicken, rats, mice,
rabbits, guinea pigs, goats, or sheep. Alternatively, an anti-MASP-2 antibody useful in the
present invention may also be derived from a subhuman primate. General techniques for
raising diagnostically and therapeutically useful antibodies in baboons may be found, for
example, in Goldenberg et al., International Patent Publication No. WO 91/11465, and in
Losman, M.J., et al., Int. J. Cancer 46:310, 1990. Sera containing immunologically active
antibodies are then produced from the blood of such immunized animals using standard
procedures well known in the art.
MONOCLONAL ANTIBODIES
In some embodiments, the MASP-2 inhibitory agent is an anti-MASP-2 monoclonal
antibody. Anti-MASP-2 monoclonal antibodies are highly specific, being directed against a
single MASP-2 epitope. As used herein, the modifier "monoclonal" indicates the character
of the antibody as being obtained from a substantially homogenous population of antibodies,
and is not to be construed as requiring production of the antibody by any particular method.
Monoclonal antibodies can be obtained using any technique that provides for the production
of antibody molecules by continuous cell lines in culture, such as the hybridoma method
described by Kohler, G., et al., Nature 256:495, 1975, or they may be made by recombinant
DNA methods (see, e.g., U.S. Patent No. 4,816,567 to Cabilly). Monoclonal antibodies may
also be isolated from phage antibody libraries using the techniques described in Clackson, T.,
et al., Nature 352:624-628, 1991, and Marks, J.D., et al., J. Mol. Biol. 222:581-597, 1991.
Such antibodies can be of any immunoglobulin class including IgG, IgM, IgE, IgA, IgD and
any subclass thereof.
For example, monoclonal antibodies can be obtained by injecting a suitable mammal
(e.g., a BALB/c mouse) with a composition comprising a MASP-2 polypeptide or portion
thereof. After a predetermined period of time, splenocytes are removed from the mouse and
suspended in a cell culture medium. The splenocytes are then fused with an immortal cell
line to form a hybridoma. The formed hybridomas are grown in cell culture and screened for
their ability to produce a monoclonal antibody against MASP-2. An example further
describing the production of anti-MASP-2 monoclonal antibodies is provided in Example 7.
(See also Current Protocols in Immunology, Vol. 1., John Wiley & Sons, pages 2.5.1-2.6.7,
1991.)
Human monoclonal antibodies may be obtained through the use of transgenic mice
that have been engineered to produce specific human antibodies in response to antigenic
challenge. In this technique, elements of the human immunoglobulin heavy and light chain
locus are introduced into strains of mice derived from embryonic stem cell lines that contain
targeted disruptions of the endogenous immunoglobulin heavy chain and light chain loci.
The transgenic mice can synthesize human antibodies specific for human antigens, such as
the MASP-2 antigens described herein, and the mice can be used to produce human MASP-2
antibody-secreting hybridomas by fusing B-cells from such animals to suitable myeloma cell
lines using conventional Kohler-Milstein technology as further described in Example 7.
Transgenic mice with a human immunoglobulin genome are commercially available
(e.g., from Abgenix, Inc., Fremont, CA, and Medarex, Inc., Annandale, N.J.). Methods for
obtaining human antibodies from transgenic mice are described, for example, by Green, L.L.,
et al., Nature Genet. 7:13, 1994; Lonberg, N., et al., Nature 368:856, 1994; and Taylor, L.D.,
et al., Int. Immun. 6:579, 1994.
Monoclonal antibodies can be isolated and purified from hybridoma cultures by a
variety of well-established techniques. Such isolation techniques include affinity
chromatography with Protein-A Sepharose, size-exclusion chromatography, and
ion-exchange chromatography (see, for example, Coligan at pages 2.7.1-2.7.12 and
pages 2.9.1-2.9.3; Baines et al., "Purification of Immunoglobulin G (IgG)," in Methods in
Molecular Biology, The Humana Press, Inc., Vol. 10, pages 79-104, 1992).
Once produced, polyclonal, monoclonal or phage-derived antibodies are first tested
for specific MASP-2 binding. A variety of assays known to those skilled in the art may be
utilized to detect antibodies which specifically bind to MASP-2. Exemplary assays include
Western blot or immunoprecipitation analysis by standard methods (e.g., as described in
Ausubel et al.), immunoelectrophoresis, enzyme-linked immuno-sorbent assays, dot blots,
inhibition or competition assays and sandwich assays (as described in Harlow and Land,
Antibodies: A Laboratory Manual, Cold Spring Harbor Laboratory Press, 1988). Once
antibodies are identified that specifically bind to MASP-2, the anti-MASP-2 antibodies are
tested for the ability to function as a MASP-2 inhibitory agent in one of several assays such
as, for example, a lectin-specific C4 cleavage assay (described in Example 2), a C3b
deposition assay (described in Example 2) or a C4b deposition assay (described in
Example 2).
The affinity of anti-MASP-2 monoclonal antibodies can be readily determined by one
of ordinary skill in the art (see, e.g., Scatchard, A., NY Acad. Sci. 51:660-672, 1949). In one
embodiment, the anti-MASP-2 monoclonal antibodies useful for the methods of the
invention bind to MASP-2 with a binding affinity of <100 nM, preferably <10 nM and most
preferably <2 nM.
CHIMERIC/HUMANIZED ANTIBODIES
Monoclonal antibodies useful in the method of the invention include chimeric
antibodies in which a portion of the heavy and/or light chain is identical with or homologous
to corresponding sequences in antibodies derived from a particular species or belonging to a
particular antibody class or subclass, while the remainder of the chain(s) is identical with or
homologous to corresponding sequences in antibodies derived from another species or
belonging to another antibody class or subclass, as well as fragments of such antibodies (U.S.
Patent No. 4,816,567, to Cabilly; and Morrison, S.L., et al., Proc. Nat'l Acad. Sci.
USA 81:6851-6855, 1984).
One form of a chimeric antibody useful in the invention is a humanized monoclonal
anti-MASP-2 antibody. Humanized forms of non-human (e.g., murine) antibodies are
chimeric antibodies, which contain minimal sequence derived from non-human
immunoglobulin. Humanized monoclonal antibodies are produced by transferring the
non-human (e.g., mouse) complementarity determining regions (CDR), from the heavy and
light variable chains of the mouse immunoglobulin into a human variable domain.
Typically, residues of human antibodies are then substituted in the framework regions of the
non-human counterparts. Furthermore, humanized antibodies may comprise residues that are
not found in the recipient antibody or in the donor antibody. These modifications are made
to further refine antibody performance. In general, the humanized antibody will comprise
substantially all of at least one, and typically two variable domains, in which all or
substantially all of the hypervariable loops correspond to those of a non-human
immunoglobulin and all or substantially all of the Fv framework regions are those of a
human immunoglobulin sequence. The humanized antibody optionally also will comprise at
least a portion of an immunoglobulin constant region (Fc), typically that of a human
immunoglobulin. For further details, see Jones, P.T., et al., Nature 321:522-525, 1986;
Reichmann, L., et al., Nature 332:323-329, 1988; and Presta, Curr. Op. Struct.
Biol. 2:593-596, 1992.
The humanized antibodies useful in the invention include human monoclonal
antibodies including at least a MASP-2 binding CDR3 region. In addition, the Fc portions
may be replaced so as to produce IgA or IgM as well as human IgG antibodies. Such
humanized antibodies will have particular clinical utility because they will specifically
recognize human MASP-2 but will not evoke an immune response in humans against the
antibody itself. Consequently, they are better suited for in vivo administration in humans,
especially when repeated or long-term administration is necessary.
An example of the generation of a humanized anti-MASP-2 antibody from a murine
anti-MASP-2 monoclonal antibody is provided herein in Example 6. Techniques for
producing humanized monoclonal antibodies are also described, for example, by Jones, P.T.,
et al., Nature 321:522, 1986; Carter, P., et al., Proc. Nat'l. Acad. Sci. USA 89:4285, 1992;
Sandhu, J.S., Crit. Rev. Biotech. 12:437, 1992; Singer, I.I., et al., J. Immun. 150:2844, 1993;
Sudhir (ed.), Antibody Engineering Protocols, Humana Press, Inc., 1995; Kelley,
"Engineering Therapeutic Antibodies," in Protein Engineering: Principles and Practice,
Cleland et al. (eds.), John Wiley & Sons, Inc., pages 399-434, 1996; and by U.S. Patent
No. 5,693,762, to Queen, 1997. In addition, there are commercial entities that will
synthesize humanized antibodies from specific murine antibody regions, such as Protein
Design Labs (Mountain View, CA).
RECOMBINANT ANTIBODIES
Anti-MASP-2 antibodies can also be made using recombinant methods. For
example, human antibodies can be made using human immunoglobulin expression libraries
(available for example, from Stratagene, Corp., La Jolla, CA) to produce fragments of human
antibodies (VH, VL, Fv, Fd, Fab or F(ab')2). These fragments are then used to construct
whole human antibodies using techniques similar to those for producing chimeric antibodies.
ANTI-IDIOTYPE ANTIBODIES
Once anti-MASP-2 antibodies are identified with the desired inhibitory activity, these
antibodies can be used to generate anti-idiotype antibodies that resemble a portion of
MASP-2 using techniques that are well known in the art. See, e.g., Greenspan, N.S., et al.,
FASEB J. 7:437, 1993. For example, antibodies that bind to MASP-2 and competitively
inhibit a MASP-2 protein interaction required for complement activation can be used to
generate anti-idiotypes that resemble the MBL binding site on MASP-2 protein and therefore
bind and neutralize a binding ligand of MASP-2 such as, for example, MBL.
IMMUNOGLOBULIN FRAGMENTS
The MASP-2 inhibitory agents useful in the method of the invention encompass not
only intact immunoglobulin molecules but also the well known fragments including Fab,
Fab', F(ab)2, F(ab')2 and Fv fragments, scFv fragments, diabodies, linear antibodies,
single-chain antibody molecules and multispecific antibodies formed from antibody
fragments.
It is well known in the art that only a small portion of an antibody molecule, the
paratope, is involved in the binding of the antibody to its epitope (see, e.g., Clark, W.R., The
Experimental Foundations of Modern Immunology, Wiley & Sons, Inc., NY, 1986). The
pFc' and Fc regions of the antibody are effectors of the classical complement pathway, but
are not involved in antigen binding. An antibody from which the pFc' region has been
enzymatically cleaved, or which has been produced without the pFc' region, is designated an
F(ab')2 fragment and retains both of the antigen binding sites of an intact antibody. An
isolated F(ab')2 fragment is referred to as a bivalent monoclonal fragment because of its two
antigen binding sites. Similarly, an antibody from which the Fc region has been
enzymatically cleaved, or which has been produced without the Fc region, is designated a
Fab fragment, and retains one of the antigen binding sites of an intact antibody molecule.
Antibody fragments can be obtained by proteolytic hydrolysis, such as by pepsin or
papain digestion of whole antibodies by conventional methods. For example, antibody
fragments can be produced by enzymatic cleavage of antibodies with pepsin to provide a
5S fragment denoted F(ab')2. This fragment can be further cleaved using a thiol reducing
agent to produce 3.5S Fab' monovalent fragments. Optionally, the cleavage reaction can be
performed using a blocking group for the sulfhydryl groups that result from cleavage of
disulfide linkages. As an alternative, an enzymatic cleavage using pepsin produces two
monovalent Fab fragments and an Fc fragment directly. These methods are described, for
example, U.S. Patent No. 4,331,647 to Goldenberg; Nisonoff, A., et al., Arch. Biochem.
Biophys. 89:230, 1960; Porter, R.R., Biochem. J. 73:119, 1959; Edelman, et al., in Methods
in Enzymology 1:422, Academic Press, 1967; and by Coligan at pages 2.8.1-2.8.10
and 2.10.-2.10.4.
In some embodiments, the use of antibody fragments lacking the Fc region are
preferred to avoid activation of the classical complement pathway which is initiated upon
binding Fc to the Fcγ receptor. There are several methods by which one can produce a
MoAb that avoids Fcγ receptor interactions. For example, the Fc region of a monoclonal
antibody can be removed chemically using partial digestion by proteolytic enzymes (such as
ficin digestion), thereby generating, for example, antigen-binding antibody fragments such as
Fab or F(ab)2 fragments (Mariani, M., et al., Mol. Immunol. 28:69-71, 1991). Alternatively,
the human γ4 IgG isotype, which does not bind Fcγ receptors, can be used during
construction of a humanized antibody as described herein. Antibodies, single chain
antibodies and antigen-binding domains that lack the Fc domain can also be engineered using
recombinant techniques described herein.
SINGLE-CHAIN ANTIBODY FRAGMENTS
Alternatively, one can create single peptide chain binding molecules specific for
MASP-2 in which the heavy and light chain Fv regions are connected. The Fv fragments
may be connected by a peptide linker to form a single-chain antigen binding protein (scFv).
These single-chain antigen binding proteins are prepared by constructing a structural gene
comprising DNA sequences encoding the VH and VL domains which are connected by an
oligonucleotide. The structural gene is inserted into an expression vector, which is
subsequently introduced into a host cell, such as E. coli. The recombinant host cells
synthesize a single polypeptide chain with a linker peptide bridging the two V domains.
Methods for producing scFvs are described for example, by Whitlow, et al., "Methods: A
Companion to Methods in Enzymology" 2:97, 1991; Bird, et al., Science 242:423, 1988; U.S.
Patent No. 4,946,778, to Ladner; Pack, P., et al., Bio/Technology 11:1271, 1993.
As an illustrative example, a MASP-2 specific scFv can be obtained by exposing
lymphocytes to MASP-2 polypeptide in vitro and selecting antibody display libraries in
phage or similar vectors (for example, through the use of immobilized or labeled MASP-2
protein or peptide). Genes encoding polypeptides having potential MASP-2 polypeptide
binding domains can be obtained by screening random peptide libraries displayed on phage
or on bacteria such as E. coli. These random peptide display libraries can be used to screen
for peptides which interact with MASP-2. Techniques for creating and screening such
random peptide display libraries are well known in the art (U.S. Patent No. 5,223,409, to
Lardner; U.S. Patent No. 4,946,778, to Ladner; U.S. Patent No. 5,403,484, to Lardner; U.S.
Patent No. 5,571,698, to Lardner; and Kay et al., Phage Display of Peptides and Proteins
Academic Press, Inc., 1996) and random peptide display libraries and kits for screening such
libraries are available commercially, for instance from CLONTECH Laboratories, Inc. (Palo
Alto, Calif.), Invitrogen Inc. (San Diego, Calif.), New England Biolabs, Inc. (Beverly,
Mass.), and Pharmacia LKB Biotechnology Inc. (Piscataway, N.J.).
Another form of an anti-MASP-2 antibody fragment useful in this aspect of the
invention is a peptide coding for a single complementarity-determining region (CDR) that
binds to an epitope on a MASP-2 antigen and inhibits MASPdependent complement
activation. CDR peptides ("minimal recognition units") can be obtained by constructing
genes encoding the CDR of an antibody of interest. Such genes are prepared, for example,
by using the polymerase chain reaction to synthesize the variable region from RNA of
antibody-producing cells (see, for example, Larrick et al., Methods: A Companion to
Methods in Enzymology 2:106, 1991; Courtenay-Luck, "Genetic Manipulation of
Monoclonal Antibodies," in Monoclonal Antibodies: Production, Engineering and Clinical
Application, Ritter et al. (eds.), page 166, Cambridge University Press, 1995; and Ward et al.,
"Genetic Manipulation and Expression of Antibodies," in Monoclonal Antibodies: Principles
and Applications, Birch et al. (eds.), page 137, Wiley-Liss, Inc., 1995).
The MASP-2 antibodies described herein are administered to a subject in need
thereof to inhibit MASPdependent complement activation. In some embodiments, the
MASP-2 inhibitory agent is a high-affinity human or humanized monoclonal anti-MASP-2
antibody with reduced effector function.
PEPTIDE INHIBITORS
In some embodiments of this aspect of the invention, the MASP-2 inhibitory agent
comprises isolated MASP-2 peptide inhibitors, including isolated natural peptide inhibitors
and synthetic peptide inhibitors that inhibit the MASPdependent complement activation
system. As used herein, the term "isolated MASP-2 peptide inhibitors" refers to peptides that
inhibit MASP-2 dependent complement activation by binding to, competing with MASP-2
for binding to another recognition molecule (e.g., MBL, H-ficolin, M-ficolin, or L-ficolin) in
the lectin pathway, and/or directly interacting with MASP-2 to inhibit MASPdependent
complement activation that are substantially pure and are essentially free of other substances
with which they may be found in nature to an extent practical and appropriate for their
intended use.
Peptide inhibitors have been used successfully in vivo to interfere with
protein-protein interactions and catalytic sites. For example, peptide inhibitors to adhesion
molecules structurally related to LFA-1 have recently been approved for clinical use in
coagulopathies (Ohman, E.M., et al., European Heart J. 16:50-55, 1995). Short linear
peptides (<30 amino acids) have been described that prevent or interfere with
integrin-dependent adhesion (Murayama, O., et al., J. Biochem. 120:445-51, 1996). Longer
peptides, ranging in length from 25 to 200 amino acid residues, have also been used
successfully to block integrin-dependent adhesion (Zhang, L., et al., J. Biol.
Chem. 271(47):29953-57, 1996). In general, longer peptide inhibitors have higher affinities
and/or slower off-rates than short peptides and may therefore be more potent inhibitors.
Cyclic peptide inhibitors have also been shown to be effective inhibitors of integrins in vivo
for the treatment of human inflammatory disease (Jackson, D.Y., et al., J. Med.
Chem. 40:3359-68, 1997). One method of producing cyclic peptides involves the synthesis
of peptides in which the terminal amino acids of the peptide are cysteines, thereby allowing
the peptide to exist in a cyclic form by disulfide bonding between the terminal amino acids,
which has been shown to improve affinity and half-life in vivo for the treatment of
hematopoietic neoplasms (e.g., U.S. Patent No. 6,649,592, to Larson).
SYNTHETIC MASP-2 PEPTIDE INHIBITORS
MASP-2 inhibitory peptides useful in the methods of this aspect of the invention are
exemplified by amino acid sequences that mimic the target regions important for MASP-2
function. The inhibitory peptides useful in the practice of the methods of the invention range
in size from about 5 amino acids to about 300 amino acids. TABLE 3 provides a list of
exemplary inhibitory peptides that may be useful in the practice of this aspect of the present
invention. A candidate MASP-2 inhibitory peptide may be tested for the ability to function
as a MASP-2 inhibitory agent in one of several assays including, for example, a lectin
specific C4 cleavage assay (described in Example 2), and a C3b deposition assay (described
in Example 2).
In some embodiments, the MASP-2 inhibitory peptides are derived from MASP-2
polypeptides and are selected from the full length mature MASP-2 protein (SEQ ID NO:6),
or from a particular domain of the MASP-2 protein such as, for example, the CUBI domain
(SEQ ID NO:8), the CUBIEGF domain (SEQ ID NO:9), the EGF domain (SEQ ID NO:11),
and the serine protease domain (SEQ ID NO:12). As previously described, the
CUBEGFCUBII regions have been shown to be required for dimerization and binding with
MBL (Thielens et al., supra). In particular, the peptide sequence TFRSDYN (SEQ ID
NO:16) in the CUBI domain of MASP-2 has been shown to be involved in binding to MBL
in a study that identified a human carrying a homozygous mutation at Asp105 to Gly105,
resulting in the loss of MASP-2 from the MBL complex (Stengaard-Pedersen, K., et al., New
England J. Med. 349:554-560, 2003).
In some embodiments, MASP-2 inhibitory peptides are derived from the lectin
proteins that bind to MASP-2 and are involved in the lectin complement pathway. Several
different lectins have been identified that are involved in this pathway, including
mannan-binding lectin (MBL), L-ficolin, M-ficolin and H-ficolin. (Ikeda, K., et al., J. Biol.
Chem. 262:7451-7454, 1987; Matsushita, M., et al., J. Exp. Med. 176:1497-2284, 2000;
Matsushita, M., et al., J. Immunol. 168:3502-3506, 2002). These lectins are present in serum
as oligomers of homotrimeric subunits, each having N-terminal collagen-like fibers with
carbohydrate recognition domains. These different lectins have been shown to bind to
MASP-2, and the lectin/MASP-2 complex activates complement through cleavage of
proteins C4 and C2. H-ficolin has an amino-terminal region of 24 amino acids, a
collagen-like domain with 11 Gly-Xaa-Yaa repeats, a neck domain of 12 amino acids, and a
fibrinogen-like domain of 207 amino acids (Matsushita, M., et al.,
J. Immunol. 168:3502-3506, 2002). H-ficolin binds to GlcNAc and agglutinates human
erythrocytes coated with LPS derived from S. typhimurium, S. minnesota and E. coli.
H-ficolin has been shown to be associated with MASP-2 and MAp19 and activates the lectin
pathway. Id. L-ficolin/P35 also binds to GlcNAc and has been shown to be associated with
MASP-2 and MAp19 in human serum and this complex has been shown to activate the lectin
pathway (Matsushita, M., et al., J. Immunol. 164:2281, 2000). Accordingly, MASP-2
inhibitory peptides useful in the present invention may comprise a region of at least 5 amino
acids selected from the MBL protein (SEQ ID NO:21), the H-ficolin protein (Genbank
accession number NM_173452), the M-ficolin protein (Genbank accession number O00602)
and the L-ficolin protein (Genbank accession number NM_015838).
More specifically, scientists have identified the MASP-2 binding site on MBL to be
within the 12 Gly-X-Y triplets "GKD GRD GTK GEK GEP GQG LRG LQG POG KLG
POG NOG PSG SOG PKG QKG DOG KS" (SEQ ID NO:26) that lie between the hinge and
the neck in the C-terminal portion of the collagen-like domain of MBP (Wallis, R., et al.,
J. Biol. Chem. 279:14065, 2004). This MASP-2 binding site region is also highly conserved
in human H-ficolin and human L-ficolin. A consensus binding site has been described that is
present in all three lectin proteins comprising the amino acid sequence "OGK-X-GP" (SEQ
ID NO:22) where the letter "O" represents hydroxyproline and the letter "X" is a
hydrophobic residue (Wallis et al., 2004, supra). Accordingly, in some embodiments,
MASP-2 inhibitory peptides useful in this aspect of the invention are at least 6 amino acids in
length and comprise SEQ ID NO:22. Peptides derived from MBL that include the amino
acid sequence "GLR GLQ GPO GKL GPO G" (SEQ ID NO:24) have been shown to bind
MASP-2 in vitro (Wallis, et al., 2004, supra). To enhance binding to MASP-2, peptides can
be synthesized that are flanked by two GPO triplets at each end ("GPO GPO GLR GLQ GPO
GKL GPO GGP OGP O" SEQ ID NO:25) to enhance the formation of triple helices as found
in the native MBL protein (as further described in Wallis, R., et al., J. Biol. Chem.
279:14065, 2004).
MASP-2 inhibitory peptides may also be derived from human H-ficolin that include
the sequence "GAO GSO GEK GAO GPQ GPO GPO GKM GPK GEO GDO" (SEQ ID
NO:27) from the consensus MASP-2 binding region in H-ficolin. Also included are peptides
derived from human L-ficolin that include the sequence "GCO GLO GAO GDK GEA GTN
GKR GER GPO GPO GKA GPO GPN GAO GEO" (SEQ ID NO:28) from the consensus
MASP-2 binding region in L-ficolin.
MASP-2 inhibitory peptides may also be derived from the C4 cleavage site such as
"LQRALEILPNRVTIKANRPFLVFI" (SEQ ID NO:29) which is the C4 cleavage site linked
to the C-terminal portion of antithrombin III (Glover, G.I., et al., Mol. Immunol. 25:1261
(1988)).
TABLE 3: EXEMPLARY MASP-2 INHIBITORY PEPTIDES
SEQ ID NO Source
SEQ ID NO:6 Human MASP-2 protein
SEQ ID NO:8 CUBI domain of MASP-2 (aa 1-121 of SEQ ID NO:6)
SEQ ID NO:9 CUBIEGF domains of MASP-2 (aa 1-166 of SEQ ID NO:6)
SEQ ID NO:10 CUBIEGFCUBII domains of MASP-2
(aa 1-293 of SEQ ID NO:6)
SEQ ID NO:11 EGF domain of MASP-2 (aa 122-166)
SEQ ID NO:12 Serine-protease domain of MASP-2 (aa 429-671)
SEQ ID NO:16 MBL binding region in MASP-2
SEQ ID NO:3 Human MAp19
SEQ ID NO:21 Human MBL protein
SEQ ID NO:22
OGK-X-GP,
Where "O" =
hydroxyproline and "X"
is a hydrophobic amino
acid residue
Synthetic peptide Consensus binding site from Human
MBL and Human ficolins
SEQ ID NO:23
OGKLG
Human MBL core binding site
SEQ ID NO:24
GLR GLQ GPO GKL
GPO G
Human MBP Triplets 6 demonstrated binding to
MASP-2
SEQ ID NO:25
GPOGPOGLRGLQGPO
GKLGPOGGPOGPO
Human MBP Triplets with GPO added to enhance
formation of triple helices
SEQ ID NO Source
SEQ ID NO:26
GKDGRDGTKGEKGEP
GQGLRGLQGPOGKLG
POGNOGPSGSOGPKG
QKGDOGKS
Human MBP Triplets 1-17
SEQ ID NO:27
GAOGSOGEKGAOGPQ
GPOGPOGKMGPKGEO
GDO
Human H-Ficolin (Hataka)
SEQ ID NO:28
GCOGLOGAOGDKGE
AGTNGKRGERGPOGP
OGKAGPOGPNGAOGE
O
Human L-Ficolin P35
SEQ ID NO:29
LQRALEILPNRVTIKA
NRPFLVFI
Human C4 cleavage site
Note: The letter "O" represents hydroxyproline. The letter "X" is a hydrophobic residue.
Peptides derived from the C4 cleavage site as well as other peptides that inhibit the
MASP-2 serine protease site can be chemically modified so that they are irreversible
protease inhibitors. For example, appropriate modifications may include, but are not
necessarily limited to, halomethyl ketones (Br, Cl, I, F) at the C-terminus, Asp or Glu, or
appended to functional side chains; haloacetyl (or other -haloacetyl) groups on amino
groups or other functional side chains; epoxide or imine-containing groups on the amino or
carboxy termini or on functional side chains; or imidate esters on the amino or carboxy
termini or on functional side chains. Such modifications would afford the advantage of
permanently inhibiting the enzyme by covalent attachment of the peptide. This could result
in lower effective doses and/or the need for less frequent administration of the peptide
inhibitor.
In addition to the inhibitory peptides described above, MASP-2 inhibitory peptides
useful in the method of the invention include peptides containing the MASPbinding
CDR3 region of anti-MASP-2 MoAb obtained as described herein. The sequence of the
CDR regions for use in synthesizing the peptides may be determined by methods known in
the art. The heavy chain variable region is a peptide that generally ranges from 100 to
150 amino acids in length. The light chain variable region is a peptide that generally ranges
from 80 to 130 amino acids in length. The CDR sequences within the heavy and light chain
variable regions include only approximately 3-25 amino acid sequences that may be easily
sequenced by one of ordinary skill in the art.
Those skilled in the art will recognize that substantially homologous variations of the
MASP-2 inhibitory peptides described above will also exhibit MASP-2 inhibitory activity.
Exemplary variations include, but are not necessarily limited to, peptides having insertions,
deletions, replacements, and/or additional amino acids on the carboxy-terminus or
amino-terminus portions of the subject peptides and mixtures thereof. Accordingly, those
homologous peptides having MASP-2 inhibitory activity are considered to be useful in the
methods of this invention. The peptides described may also include duplicating motifs and
other modifications with conservative substitutions. Conservative variants are described
elsewhere herein, and include the exchange of an amino acid for another of like charge, size
or hydrophobicity and the like.
MASP-2 inhibitory peptides may be modified to increase solubility and/or to
maximize the positive or negative charge in order to more closely resemble the segment in
the intact protein. The derivative may or may not have the exact primary amino acid
structure of a peptide disclosed herein so long as the derivative functionally retains the
desired property of MASP-2 inhibition. The modifications can include amino acid
substitution with one of the commonly known twenty amino acids or with another amino
acid, with a derivatized or substituted amino acid with ancillary desirable characteristics,
such as resistance to enzymatic degradation or with a D-amino acid or substitution with
another molecule or compound, such as a carbohydrate, which mimics the natural
confirmation and function of the amino acid, amino acids or peptide; amino acid deletion;
amino acid insertion with one of the commonly known twenty amino acids or with another
amino acid, with a derivatized or substituted amino acid with ancillary desirable
characteristics, such as resistance to enzymatic degradation or with a D-amino acid or
substitution with another molecule or compound, such as a carbohydrate, which mimics the
natural confirmation and function of the amino acid, amino acids or peptide; or substitution
with another molecule or compound, such as a carbohydrate or nucleic acid monomer, which
mimics the natural conformation, charge distribution and function of the parent peptide.
Peptides may also be modified by acetylation or amidation.
The synthesis of derivative inhibitory peptides can rely on known techniques of
peptide biosynthesis, carbohydrate biosynthesis and the like. As a starting point, the artisan
may rely on a suitable computer program to determine the conformation of a peptide of
interest. Once the conformation of peptide disclosed herein is known, then the artisan can
determine in a rational design fashion what sort of substitutions can be made at one or more
sites to fashion a derivative that retains the basic conformation and charge distribution of the
parent peptide but which may possess characteristics which are not present or are enhanced
over those found in the parent peptide. Once candidate derivative molecules are identified,
the derivatives can be tested to determine if they function as MASP-2 inhibitory agents using
the assays described herein.
SCREENING FOR MASP-2 INHIBITORY PEPTIDES
One may also use molecular modeling and rational molecular design to generate and
screen for peptides that mimic the molecular structures of key binding regions of MASP-2
and inhibit the complement activities of MASP-2. The molecular structures used for
modeling include the CDR regions of anti-MASP-2 monoclonal antibodies, as well as the
target regions known to be important for MASP-2 function including the region required for
dimerization, the region involved in binding to MBL, and the serine protease active site as
previously described. Methods for identifying peptides that bind to a particular target are
well known in the art. For example, molecular imprinting may be used for the de novo
construction of macromolecular structures such as peptides that bind to a particular molecule.
See, for example, Shea, K.J., "Molecular Imprinting of Synthetic Network Polymers: The
De Novo synthesis of Macromolecular Binding and Catalytic Sties," TRIP 2(5) 1994.
As an illustrative example, one method of preparing mimics of MASP-2 binding
peptides is as follows. Functional monomers of a known MASP-2 binding peptide or the
binding region of an anti-MASP-2 antibody that exhibits MASP-2 inhibition (the template)
are polymerized. The template is then removed, followed by polymerization of a second
class of monomers in the void left by the template, to provide a new molecule that exhibits
one or more desired properties that are similar to the template. In addition to preparing
peptides in this manner, other MASP-2 binding molecules that are MASP-2 inhibitory agents
such as polysaccharides, nucleosides, drugs, nucleoproteins, lipoproteins, carbohydrates,
glycoproteins, steroid, lipids and other biologically active materials can also be prepared.
This method is useful for designing a wide variety of biological mimics that are more stable
than their natural counterparts because they are typically prepared by free radical
polymerization of function monomers, resulting in a compound with a nonbiodegradable
backbone.
PEPTIDE SYNTHESIS
The MASP-2 inhibitory peptides can be prepared using techniques well known in the
art, such as the solid-phase synthetic technique initially described by Merrifield, in J. Amer.
Chem. Soc. 85:2149-2154, 1963. Automated synthesis may be achieved, for example, using
Applied Biosystems 431A Peptide Synthesizer (Foster City, Calif.) in accordance with the
instructions provided by the manufacturer. Other techniques may be found, for example, in
Bodanszky, M., et al., Peptide Synthesis, second edition, John Wiley & Sons, 1976, as well
as in other reference works known to those skilled in the art.
The peptides can also be prepared using standard genetic engineering techniques
known to those skilled in the art. For example, the peptide can be produced enzymatically by
inserting nucleic acid encoding the peptide into an expression vector, expressing the DNA,
and translating the DNA into the peptide in the presence of the required amino acids. The
peptide is then purified using chromatographic or electrophoretic techniques, or by means of
a carrier protein that can be fused to, and subsequently cleaved from, the peptide by inserting
into the expression vector in phase with the peptide encoding sequence a nucleic acid
sequence encoding the carrier protein. The fusion protein-peptide may be isolated using
chromatographic, electrophoretic or immunological techniques (such as binding to a resin via
an antibody to the carrier protein). The peptide can be cleaved using chemical methodology
or enzymatically, as by, for example, hydrolases.
The MASP-2 inhibitory peptides that are useful in the method of the invention can
also be produced in recombinant host cells following conventional techniques. To express a
MASP-2 inhibitory peptide encoding sequence, a nucleic acid molecule encoding the peptide
must be operably linked to regulatory sequences that control transcriptional expression in an
expression vector and then introduced into a host cell. In addition to transcriptional
regulatory sequences, such as promoters and enhancers, expression vectors can include
translational regulatory sequences and a marker gene, which are suitable for selection of cells
that carry the expression vector.
Nucleic acid molecules that encode a MASP-2 inhibitory peptide can be synthesized
with "gene machines" using protocols such as the phosphoramidite method. If chemically
synthesized double-stranded DNA is required for an application such as the synthesis of a
gene or a gene fragment, then each complementary strand is made separately. The
production of short genes (60 to 80 base pairs) is technically straightforward and can be
accomplished by synthesizing the complementary strands and then annealing them. For the
production of longer genes, synthetic genes (double-stranded) are assembled in modular form
from single-stranded fragments that are from 20 to 100 nucleotides in length. For reviews on
polynucleotide synthesis, see, for example, Glick and Pasternak, "Molecular Biotechnology,
Principles and Applications of Recombinant DNA", ASM Press, 1994; Itakura, K., et al.,
Annu. Rev. Biochem. 53:323, 1984; and Climie, S., et al., Proc. Nat'l Acad. Sci. USA 87:633,
1990.
SMALL MOLECULE INHIBITORS
In some embodiments, MASP-2 inhibitory agents are small molecule inhibitors
including natural and synthetic substances that have a low molecular weight, such as for
example, peptides, peptidomimetics and nonpeptide inhibitors (including oligonucleotides
and organic compounds). Small molecule inhibitors of MASP-2 can be generated based on
the molecular structure of the variable regions of the anti-MASP-2 antibodies.
Small molecule inhibitors may also be designed and generated based on the MASP-2
crystal structure using computational drug design (Kuntz I.D., et al., Science 257:1078,
1992). The crystal structure of rat MASP-2 has been described (Feinberg, H., et al.,
EMBO J. 22:2348-2359, 2003). Using the method described by Kuntz et al., the MASP-2
crystal structure coordinates are used as an input for a computer program such as DOCK,
which outputs a list of small molecule structures that are expected to bind to MASP-2. Use
of such computer programs is well known to one of skill in the art. For example, the crystal
structure of the HIV-1 protease inhibitor was used to identify unique nonpeptide ligands that
are HIV-1 protease inhibitors by evaluating the fit of compounds found in the Cambridge
Crystallographic database to the binding site of the enzyme using the program DOCK
(Kuntz, I.D., et al., J. Mol. Biol. 161:269-288, 1982; DesJarlais, R.L., et al.,
PNAS 87:6644-6648, 1990).
The list of small molecule structures that are identified by a computational method as
potential MASP-2 inhibitors are screened using a MASP-2 binding assay such as described
in Example 10. The small molecules that are found to bind to MASP-2 are then assayed in a
functional assay such as described in Example 2 to determine if they inhibit
MASPdependent complement activation.
MASP-2 SOLUBLE RECEPTORS
Other suitable MASP-2 inhibitory agents are believed to include MASP-2 soluble
receptors, which may be produced using techniques known to those of ordinary skill in the
art.
EXPRESSION INHIBITORS OF MASP-2
In another embodiment of this aspect of the invention, the MASP-2 inhibitory agent
is a MASP-2 expression inhibitor capable of inhibiting MASPdependent complement
activation. In the practice of this aspect of the invention, representative MASP-2 expression
inhibitors include MASP-2 antisense nucleic acid molecules (such as antisense mRNA,
antisense DNA or antisense oligonucleotides), MASP-2 ribozymes and MASP-2 RNAi
molecules.
Anti-sense RNA and DNA molecules act to directly block the translation of MASP-2
mRNA by hybridizing to MASP-2 mRNA and preventing translation of MASP-2 protein.
An antisense nucleic acid molecule may be constructed in a number of different ways
provided that it is capable of interfering with the expression of MASP-2. For example, an
antisense nucleic acid molecule can be constructed by inverting the coding region (or a
portion thereof) of MASP-2 cDNA (SEQ ID NO:4) relative to its normal orientation for
transcription to allow for the transcription of its complement.
The antisense nucleic acid molecule is usually substantially identical to at least a
portion of the target gene or genes. The nucleic acid, however, need not be perfectly
identical to inhibit expression. Generally, higher homology can be used to compensate for
the use of a shorter antisense nucleic acid molecule. The minimal percent identity is
typically greater than about 65%, but a higher percent identity may exert a more effective
repression of expression of the endogenous sequence. Substantially greater percent identity
of more than about 80% typically is preferred, though about 95% to absolute identity is
typically most preferred.
The antisense nucleic acid molecule need not have the same intron or exon pattern as
the target gene, and non-coding segments of the target gene may be equally effective in
achieving antisense suppression of target gene expression as coding segments. A DNA
sequence of at least about 8 or so nucleotides may be used as the antisense nucleic acid
molecule, although a longer sequence is preferable. In the present invention, a representative
example of a useful inhibitory agent of MASP-2 is an antisense MASP-2 nucleic acid
molecule which is at least ninety percent identical to the complement of the MASP-2 cDNA
consisting of the nucleic acid sequence set forth in SEQ ID NO:4. The nucleic acid sequence
set forth in SEQ ID NO:4 encodes the MASP-2 protein consisting of the amino acid
sequence set forth in SEQ ID NO:5.
The targeting of antisense oligonucleotides to bind MASP-2 mRNA is another
mechanism that may be used to reduce the level of MASP-2 protein synthesis. For example,
the synthesis of polygalacturonase and the muscarine type 2 acetylcholine receptor is
inhibited by antisense oligonucleotides directed to their respective mRNA sequences (U.S.
Patent No. 5,739,119, to Cheng, and U.S. Patent No. 5,759,829, to Shewmaker).
Furthermore, examples of antisense inhibition have been demonstrated with the nuclear
protein cyclin, the multiple drug resistance gene (MDG1), ICAM-1, E-selectin, STK-1,
striatal GABAA receptor and human EGF (see, e.g., U.S. Patent No. 5,801,154, to
Baracchini; U.S. Patent No. 5,789,573, to Baker; U.S. Patent No. 5,718,709, to Considine;
and U.S. Patent No. 5,610,288, to Reubenstein).
A system has been described that allows one of ordinary skill to determine which
oligonucleotides are useful in the invention, which involves probing for suitable sites in the
target mRNA using Rnase H cleavage as an indicator for accessibility of sequences within
the transcripts. Scherr, M., et al., Nucleic Acids Res. 26:5079-5085, 1998; Lloyd, et al.,
Nucleic Acids Res. 29:3665-3673, 2001. A mixture of antisense oligonucleotides that are
complementary to certain regions of the MASP-2 transcript is added to cell extracts
expressing MASP-2, such as hepatocytes, and hybridized in order to create an RNAseH
vulnerable site. This method can be combined with computer-assisted sequence selection
that can predict optimal sequence selection for antisense compositions based upon their
relative ability to form dimers, hairpins, or other secondary structures that would reduce or
prohibit specific binding to the target mRNA in a host cell. These secondary structure
analysis and target site selection considerations may be performed using the OLIGO primer
analysis software (Rychlik, I., 1997) and the BLASTN 2.0.5 algorithm software (Altschul,
S.F., et al., Nucl. Acids Res. 25:3389-3402, 1997). The antisense compounds directed
towards the target sequence preferably comprise from about 8 to about 50 nucleotides in
length. Antisense oligonucleotides comprising from about 9 to about 35 or so nucleotides
are particularly preferred. The inventors contemplate all oligonucleotide compositions in the
range of 9 to 35 nucleotides (i.e., those of 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22,
23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, or 35 or so bases in length) are highly preferred
for the practice of antisense oligonucleotide-based methods of the invention. Highly
preferred target regions of the MASP-2 mRNA are those that are at or near the AUG
translation initiation codon, and those sequences that are substantially complementary to 5'
regions of the mRNA, e.g., between the –10 and +10 regions of the MASP-2 gene nucleotide
sequence (SEQ ID NO:4). Exemplary MASP-2 expression inhibitors are provided in
TABLE 4.
TABLE 4: EXEMPLARY EXPRESSION INHIBITORS OF MASP-2
SEQ ID NO:30 (nucleotides 22-680 of
SEQ ID NO:4)
Nucleic acid sequence of MASP-2 cDNA
(SEQ ID NO:4) encoding CUBIEGF
SEQ ID NO:31
'CGGGCACACCATGAGGCTGCTG
ACCCTCCTGGGC3
Nucleotides 12-45 of SEQ ID NO:4
including the MASP-2 translation start site
(sense)
SEQ ID NO:32
'GACATTACCTTCCGCTCCGACTC
CAACGAGAAG3'
Nucleotides 361-396 of SEQ ID NO:4
encoding a region comprising the MASP-2
MBL binding site (sense)
SEQ ID NO:33
'AGCAGCCCTGAATACCCACGGCC
GTATCCCAAA3'
Nucleotides 610-642 of SEQ ID NO:4
encoding a region comprising the CUBII
domain
As noted above, the term "oligonucleotide" as used herein refers to an oligomer or
polymer of ribonucleic acid (RNA) or deoxyribonucleic acid (DNA) or mimetics thereof.
This term also covers those oligonucleobases composed of naturally occurring nucleotides,
sugars and covalent internucleoside (backbone) linkages as well as oligonucleotides having
non-naturally occurring modifications. These modifications allow one to introduce certain
desirable properties that are not offered through naturally occurring oligonucleotides, such as
reduced toxic properties, increased stability against nuclease degradation and enhanced
cellular uptake. In illustrative embodiments, the antisense compounds of the invention differ
from native DNA by the modification of the phosphodiester backbone to extend the life of
the antisense oligonucleotide in which the phosphate substituents are replaced by
phosphorothioates. Likewise, one or both ends of the oligonucleotide may be substituted by
one or more acridine derivatives that intercalate between adjacent basepairs within a strand
of nucleic acid.
Another alternative to antisense is the use of "RNA interference" (RNAi).
Double-stranded RNAs (dsRNAs) can provoke gene silencing in mammals in vivo. The
natural function of RNAi and co-suppression appears to be protection of the genome against
invasion by mobile genetic elements such as retrotransposons and viruses that produce
aberrant RNA or dsRNA in the host cell when they become active (see, e.g., Jensen, J., et al.,
Nat. Genet. 21:209-12, 1999). The double-stranded RNA molecule may be prepared by
synthesizing two RNA strands capable of forming a double-stranded RNA molecule, each
having a length from about 19 to 25 (e.g., 19-23 nucleotides). For example, a dsRNA
molecule useful in the methods of the invention may comprise the RNA corresponding to a
sequence and its complement listed in TABLE 4. Preferably, at least one strand of RNA has
a 3' overhang from 1-5 nucleotides. The synthesized RNA strands are combined under
conditions that form a double-stranded molecule. The RNA sequence may comprise at least
an 8 nucleotide portion of SEQ ID NO:4 with a total length of 25 nucleotides or less. The
design of siRNA sequences for a given target is within the ordinary skill of one in the art.
Commercial services are available that design siRNA sequence and guarantee at least 70%
knockdown of expression (Qiagen, Valencia, Calif).
The dsRNA may be administered as a pharmaceutical composition and carried out by
known methods, wherein a nucleic acid is introduced into a desired target cell. Commonly
used gene transfer methods include calcium phosphate, DEAE-dextran, electroporation,
microinjection and viral methods. Such methods are taught in Ausubel et al., Current
Protocols in Molecular Biology, John Wiley & Sons, Inc., 1993.
Ribozymes can also be utilized to decrease the amount and/or biological activity of
MASP-2, such as ribozymes that target MASP-2 mRNA. Ribozymes are catalytic RNA
molecules that can cleave nucleic acid molecules having a sequence that is completely or
partially homologous to the sequence of the ribozyme. It is possible to design ribozyme
transgenes that encode RNA ribozymes that specifically pair with a target RNA and cleave
the phosphodiester backbone at a specific location, thereby functionally inactivating the
target RNA. In carrying out this cleavage, the ribozyme is not itself altered, and is thus
capable of recycling and cleaving other molecules. The inclusion of ribozyme sequences
within antisense RNAs confers RNA-cleaving activity upon them, thereby increasing the
activity of the antisense constructs.
Ribozymes useful in the practice of the invention typically comprise a hybridizing
region of at least about nine nucleotides, which is complementary in nucleotide sequence to
at least part of the target MASP-2 mRNA, and a catalytic region that is adapted to cleave the
target MASP-2 mRNA (see generally, EPA No. 0 321 201; WO88/04300; Haseloff, J., et al.,
Nature 334:585-591, 1988; Fedor, M.J., et al., Proc. Natl. Acad. Sci. USA 87:1668-1672,
1990; Cech, T.R., et al., Ann. Rev. Biochem. 55:599-629, 1986).
Ribozymes can either be targeted directly to cells in the form of RNA
oligonucleotides incorporating ribozyme sequences, or introduced into the cell as an
expression vector encoding the desired ribozymal RNA. Ribozymes may be used and
applied in much the same way as described for antisense polynucleotides.
Anti-sense RNA and DNA, ribozymes and RNAi molecules useful in the methods of
the invention may be prepared by any method known in the art for the synthesis of DNA and
RNA molecules. These include techniques for chemically synthesizing
oligodeoxyribonucleotides and oligoribonucleotides well known in the art, such as for
example solid phase phosphoramidite chemical synthesis. Alternatively, RNA molecules
may be generated by in vitro and in vivo transcription of DNA sequences encoding the
antisense RNA molecule. Such DNA sequences may be incorporated into a wide variety of
vectors that incorporate suitable RNA polymerase promoters such as the T7 or SP6
polymerase promoters. Alternatively, antisense cDNA constructs that synthesize antisense
RNA constitutively or inducibly, depending on the promoter used, can be introduced stably
into cell lines.
Various well known modifications of the DNA molecules may be introduced as a
means of increasing stability and half-life. Useful modifications include, but are not limited
to, the addition of flanking sequences of ribonucleotides or deoxyribonucleotides to the 5'
and/or 3' ends of the molecule or the use of phosphorothioate or 2' O-methyl rather than
phosphodiesterase linkages within the oligodeoxyribonucleotide backbone.
V. PHARMACEUTICAL COMPOSITIONS AND DELIVERY METHODS
DOSING
In another aspect, the invention provides compositions for inhibiting the adverse
effects of MASPdependent complement activation in a subject suffering from a disease or
condition as disclosed herein, comprising administering to the subject a composition
comprising a therapeutically effective amount of a MASP-2 inhibitory agent and a
pharmaceutically acceptable carrier. The MASP-2 inhibitory agents can be administered to a
subject in need thereof, at therapeutically effective doses to treat or ameliorate conditions
associated with MASPdependent complement activation. A therapeutically effective dose
refers to the amount of the MASP-2 inhibitory agent sufficient to result in amelioration of
symptoms associated with the disease or condition.
Toxicity and therapeutic efficacy of MASP-2 inhibitory agents can be determined by
standard pharmaceutical procedures employing experimental animal models, such as the
murine MASP-2 -/- mouse model expressing the human MASP-2 transgene described in
Example 1. Using such animal models, the NOAEL (no observed adverse effect level) and
the MED (the minimally effective dose) can be determined using standard methods. The
dose ratio between NOAEL and MED effects is the therapeutic ratio, which is expressed as
the ratio NOAEL/MED. MASP-2 inhibitory agents that exhibit large therapeutic ratios or
indices are most preferred. The data obtained from the cell culture assays and animal studies
can be used in formulating a range of dosages for use in humans. The dosage of the MASP-2
inhibitory agent preferably lies within a range of circulating concentrations that include the
MED with little or no toxicity. The dosage may vary within this range depending upon the
dosage form employed and the route of administration utilized.
For any compound formulation, the therapeutically effective dose can be estimated
using animal models. For example, a dose may be formulated in an animal model to achieve
a circulating plasma concentration range that includes the MED. Quantitative levels of the
MASP-2 inhibitory agent in plasma may also be measured, for example, by high
performance liquid chromatography.
In addition to toxicity studies, effective dosage may also be estimated based on the
amount of MASP-2 protein present in a living subject and the binding affinity of the
MASP-2 inhibitory agent. It has been shown that MASP-2 levels in normal human subjects
is present in serum in low levels in the range of 500 ng/ml, and MASP-2 levels in a particular
subject can be determined using a quantitative assay for MASP-2 described in
Moller-Kristensen M., et al., J. Immunol. Methods 282:159-167, 2003.
Generally, the dosage of administered compositions comprising MASP-2 inhibitory
agents varies depending on such factors as the subject's age, weight, height, sex, general
medical condition, and previous medical history. As an illustration, MASP-2 inhibitory
agents, such as anti-MASP-2 antibodies, can be administered in dosage ranges from
about 0.010 to 10.0 mg/kg, preferably 0.010 to 1.0 mg/kg, more preferably 0.010 to
0.1 mg/kg of the subject body weight. In some embodiments the composition comprises a
combination of anti-MASP-2 antibodies and MASP-2 inhibitory peptides.
Therapeutic efficacy of MASP-2 inhibitory compositions and methods of the present
invention in a given subject, and appropriate dosages, can be determined in accordance with
complement assays well known to those of skill in the art. Complement generates numerous
specific products. During the last decade, sensitive and specific assays have been developed
and are available commercially for most of these activation products, including the small
activation fragments C3a, C4a, and C5a and the large activation fragments iC3b, C4d, Bb,
and sC5b-9. Most of these assays utilize monoclonal antibodies that react with new antigens
(neoantigens) exposed on the fragment, but not on the native proteins from which they are
formed, making these assays very simple and specific. Most rely on ELISA technology,
although radioimmunoassay is still sometimes used for C3a and C5a. These latter assays
measure both the unprocessed fragments and their 'desArg' fragments, which are the major
forms found in the circulation. Unprocessed fragments and C5adesArg are rapidly cleared by
binding to cell surface receptors and are hence present in very low concentrations,
whereas C3adesArg does not bind to cells and accumulates in plasma. Measurement of C3a
provides a sensitive, pathway-independent indicator of complement activation. Alternative
pathway activation can be assessed by measuring the Bb fragment. Detection of the
fluid-phase product of membrane attack pathway activation, sC5b-9, provides evidence that
complement is being activated to completion. Because both the lectin and classical pathways
generate the same activation products, C4a and C4d, measurement of these two fragments
does not provide any information about which of these two pathways has generated the
activation products.
The inhibition of MASPdependent complement activation is characterized by at
least one of the following changes in a component of the complement system that occurs as a
result of administration of a MASP-2 inhibitory agent in accordance with the methods of the
invention: the inhibition of the generation or production of MASPdependent complement
activation system products C4b, C3a, C5a and/or C5b-9 (MAC) (measured, for example, as
described in measured, for example, as described in Example 2, the reduction of C4 cleavage
and C4b deposition (measured, for example as described in Example 10), or the reduction of
C3 cleavage and C3b deposition (measured, for example, as described in Example10).
ADDITIONAL AGENTS
The compositions and methods comprising MASP-2 inhibitory agents may optionally
comprise one or more additional therapeutic agents, which may augment the activity of the
MASP-2 inhibitory agent or that provide related therapeutic functions in an additive or
synergistic fashion. For example, in the context of treating a subject suffering from TTP,
wherein the subject is positive for an inhibitor of ADAM-TS13, one or more MASP-2
inhibitory agents may be administered in combination (including co-administration) with one
or more immunosuppressive agents. Suitable immunosuppressive agents include:
corticosteroids, rituxan, cyclosporine, and the like. In the context of treating a subject
suffering from, or at risk for developing, HUS or aHUS, one or more MASP-2 inhibitory
agents may be administered in combination (including co-administration) with a suitable
antibiotic. In the context of treating a subject suffering from, or at risk for developing aHUS,
one or more MASP-2 inhibitory agents may be administered in combination (including co5 administration) with other complement inhibitory agents such as eculizumab (Soliris), TT30, antibody to factor B, or other agents that inhibit terminal complement components or
alternative pathway amplification.
The inclusion and selection of additional agent(s) will be determined to achieve a
desired therapeutic result. In some embodiments, the MASP-2 inhibitory agent may be
administered in combination with one or more anti-inflammatory and/or analgesic agents.
Suitable anti-inflammatory and/or analgesic agents include: serotonin receptor antagonists;
serotonin receptor agonists; histamine receptor antagonists; bradykinin receptor antagonists;
kallikrein inhibitors; tachykinin receptor antagonists, including neurokinin1 and neurokinin2
receptor subtype antagonists; calcitonin gene-related peptide (CGRP) receptor antagonists;
interleukin receptor antagonists; inhibitors of enzymes active in the synthetic pathway for
arachidonic acid metabolites, including phospholipase inhibitors, including PLA2 isoform
inhibitors and PLC isoform inhibitors, cyclooxygenase (COX) inhibitors (which may be
either COX-1, COX-2, or nonselective COX-1 and -2 inhibitors), lipooxygenase inhibitors;
prostanoid receptor antagonists including eicosanoid EP-1 and EP-4 receptor subtype
antagonists and thromboxane receptor subtype antagonists; leukotriene receptor antagonists
including leukotriene B4 receptor subtype antagonists and leukotriene D4 receptor subtype
antagonists; opioid receptor agonists, including -opioid, -opioid, and -opioid receptor
subtype agonists; purinoceptor agonists and antagonists including P2X receptor antagonists
and P2Y receptor agonists; adenosine triphosphate (ATP)-sensitive potassium channel
openers; MAP kinase inhibitors; nicotinic acetylcholine inhibitors; and alpha adrenergic
receptor agonists (including alpha-1, alpha-2, and nonselective alpha-1 and 2 agonists).
The MASP-2 inhibitory agents of the present invention may also be administered in
combination with one or more other complement inhibitors, such as an inhibitor of C5. To
date, Eculizumab (Solaris®), an antibody against C5, is the only complement-targeting drug
that has been approved for human use. However some pharmacological agents have been
shown to block complement in vivo. K76COOH and nafamstat mesilate are two agents that
have shown some effectiveness in animal models of transplantation (Miyagawa, S., et al.,
Transplant Proc. 24:483-484, 1992). Low molecular weight heparins have also been shown
to be effective in regulating complement activity (Edens, R.E., et al., Complement Today,
pp. 96-120, Basel: Karger, 1993). It is believed that these small molecule inhibitors may be
useful as agents to use in combination with the MASP-2 inhibitory agents of the present
invention.
Other naturally occurring complement inhibitors may be useful in combination with
the MASP-2 inhibitory agents of the present invention. Biological inhibitors of complement
include soluble complement factor 1 (sCR1). This is a naturally-occurring inhibitor that can
be found on the outer membrane of human cells. Other membrane inhibitors include DAF,
MCP, and CD59. Recombinant forms have been tested for their anti-complement activity in
vitro and in vivo. sCR1 has been shown to be effective in xenotransplantation, wherein the
complement system (both alternative and classical) provides the trigger for a hyperactive
rejection syndrome within minutes of perfusing blood through the newly transplanted organ
(Platt, J.L., et al., Immunol. Today 11:450-6, 1990; Marino, I.R., et al., Transplant
Proc. 1071:6, 1990; Johnstone, P.S., et al., Transplantation 54:573-6, 1992). The use
of sCR1 protects and extends the survival time of the transplanted organ, implicating the
complement pathway in the pathogenesis of organ survival (Leventhal, J.R., et al.,
Transplantation 55:857-66, 1993; Pruitt, S.K., et al., Transplantation 57:363-70, 1994).
Suitable additional complement inhibitors for use in combination with the
compositions of the present invention also include, by way of example, MoAbs such as an
anti-C5 antibody (e.g., eculizumab) being developed by Alexion Pharmaceuticals, Inc., New
Haven, Connecticut, and anti-properdin MoAbs.
PHARMACEUTICAL CARRIERS AND DELIVERY VEHICLES
In general, the MASP-2 inhibitory agent compositions of the present invention,
combined with any other selected therapeutic agents, are suitably contained in a
pharmaceutically acceptable carrier. The carrier is non-toxic, biocompatible and is selected
so as not to detrimentally affect the biological activity of the MASP-2 inhibitory agent (and
any other therapeutic agents combined therewith). Exemplary pharmaceutically acceptable
carriers for peptides are described in U.S. Patent No. 5,211,657 to Yamada. The
anti-MASP-2 antibodies and inhibitory peptides useful in the invention may be formulated
into preparations in solid, semi-solid, gel, liquid or gaseous forms such as tablets, capsules,
powders, granules, ointments, solutions, depositories, inhalants and injections allowing for
oral, parenteral or surgical administration. The invention also contemplates local
administration of the compositions by coating medical devices and the like.
Suitable carriers for parenteral delivery via injectable, infusion or irrigation and
topical delivery include distilled water, physiological phosphate-buffered saline, normal or
lactated Ringer's solutions, dextrose solution, Hank's solution, or propanediol. In addition,
sterile, fixed oils may be employed as a solvent or suspending medium. For this purpose any
biocompatible oil may be employed including synthetic mono- or diglycerides. In addition,
fatty acids such as oleic acid find use in the preparation of injectables. The carrier and agent
may be compounded as a liquid, suspension, polymerizable or non-polymerizable gel, paste
or salve.
The carrier may also comprise a delivery vehicle to sustain (i.e., extend, delay or
regulate) the delivery of the agent(s) or to enhance the delivery, uptake, stability or
pharmacokinetics of the therapeutic agent(s). Such a delivery vehicle may include, by way
of non-limiting example, microparticles, microspheres, nanospheres or nanoparticles
composed of proteins, liposomes, carbohydrates, synthetic organic compounds, inorganic
compounds, polymeric or copolymeric hydrogels and polymeric micelles. Suitable hydrogel
and micelle delivery systems include the PEO:PHB:PEO copolymers and
copolymer/cyclodextrin complexes disclosed in WO 2004/009664 A2 and the PEO and
PEO/cyclodextrin complexes disclosed in U.S. Patent Application Publication
No. 2002/0019369 A1. Such hydrogels may be injected locally at the site of intended action,
or subcutaneously or intramuscularly to form a sustained release depot.
For intra-articular delivery, the MASP-2 inhibitory agent may be carried in
above-described liquid or gel carriers that are injectable, above-described sustained-release
delivery vehicles that are injectable, or a hyaluronic acid or hyaluronic acid derivative.
For oral administration of non-peptidergic agents, the MASP-2 inhibitory agent may
be carried in an inert filler or diluent such as sucrose, cornstarch, or cellulose.
For topical administration, the MASP-2 inhibitory agent may be carried in ointment,
lotion, cream, gel, drop, suppository, spray, liquid or powder, or in gel or microcapsular
delivery systems via a transdermal patch.
Various nasal and pulmonary delivery systems, including aerosols, metered-dose
inhalers, dry powder inhalers, and nebulizers, are being developed and may suitably be
adapted for delivery of the present invention in an aerosol, inhalant, or nebulized delivery
vehicle, respectively.
For intrathecal (IT) or intracerebroventricular (ICV) delivery, appropriately sterile
delivery systems (e.g., liquids; gels, suspensions, etc.) can be used to administer the present
invention.
The compositions of the present invention may also include biocompatible excipients,
such as dispersing or wetting agents, suspending agents, diluents, buffers, penetration
enhancers, emulsifiers, binders, thickeners, flavouring agents (for oral administration).
PHARMACEUTICAL CARRIERS FOR ANTIBODIES AND PEPTIDES
More specifically with respect to anti-MASP-2 antibodies and inhibitory peptides,
exemplary formulations can be parenterally administered as injectable dosages of a solution
or suspension of the compound in a physiologically acceptable diluent with a pharmaceutical
carrier that can be a sterile liquid such as water, oils, saline, glycerol or ethanol.
Additionally, auxiliary substances such as wetting or emulsifying agents, surfactants, pH
buffering substances and the like can be present in compositions comprising anti-MASP-2
antibodies and inhibitory peptides. Additional components of pharmaceutical compositions
include petroleum (such as of animal, vegetable or synthetic origin), for example, soybean oil
and mineral oil. In general, glycols such as propylene glycol or polyethylene glycol are
preferred liquid carriers for injectable solutions.
The anti-MASP-2 antibodies and inhibitory peptides can also be administered in the
form of a depot injection or implant preparation that can be formulated in such a manner as
to permit a sustained or pulsatile release of the active agents.
PHARMACEUTICALLY ACCEPTABLE CARRIERS FOR EXPRESSION
INHIBITORS
More specifically with respect to expression inhibitors useful in the methods of the
invention, compositions are provided that comprise an expression inhibitor as described
above and a pharmaceutically acceptable carrier or diluent. The composition may further
comprise a colloidal dispersion system.
Pharmaceutical compositions that include expression inhibitors may include, but are
not limited to, solutions, emulsions, and liposome-containing formulations. These
compositions may be generated from a variety of components that include, but are not
limited to, preformed liquids, self-emulsifying solids and self-emulsifying semisolids. The
preparation of such compositions typically involves combining the expression inhibitor with
one or more of the following: buffers, antioxidants, low molecular weight polypeptides,
proteins, amino acids, carbohydrates including glucose, sucrose or dextrins, chelating agents
such as EDTA, glutathione and other stabilizers and excipients. Neutral buffered saline or
saline mixed with non-specific serum albumin are examples of suitable diluents.
In some embodiments, the compositions may be prepared and formulated as
emulsions which are typically heterogeneous systems of one liquid dispersed in another in
the form of droplets (see, Idson, in Pharmaceutical Dosage Forms, Vol. 1, Rieger and
Banker (eds.), Marcek Dekker, Inc., N.Y., 1988). Examples of naturally occurring
emulsifiers used in emulsion formulations include acacia, beeswax, lanolin, lecithin and
phosphatides.
In one embodiment, compositions including nucleic acids can be formulated as
microemulsions. A microemulsion, as used herein refers to a system of water, oil, and
amphiphile, which is a single optically isotropic and thermodynamically stable liquid
solution (see Rosoff in Pharmaceutical Dosage Forms, Vol. 1). The method of the invention
may also use liposomes for the transfer and delivery of antisense oligonucleotides to the
desired site.
Pharmaceutical compositions and formulations of expression inhibitors for topical
administration may include transdermal patches, ointments, lotions, creams, gels, drops,
suppositories, sprays, liquids and powders. Conventional pharmaceutical carriers, as well as
aqueous, powder or oily bases and thickeners and the like may be used.
MODES OF ADMINISTRATION
The pharmaceutical compositions comprising MASP-2 inhibitory agents may be
administered in a number of ways depending on whether a local or systemic mode of
administration is most appropriate for the condition being treated. Additionally, as described
herein above with respect to extracorporeal reperfusion procedures, MASP-2 inhibitory
agents can be administered via introduction of the compositions of the present invention to
recirculating blood or plasma. Further, the compositions of the present invention can be
delivered by coating or incorporating the compositions on or into an implantable medical
device.
SYSTEMIC DELIVERY
As used herein, the terms "systemic delivery" and "systemic administration" are
intended to include but are not limited to oral and parenteral routes including intramuscular
(IM), subcutaneous, intravenous (IV), intra-arterial, inhalational, sublingual, buccal, topical,
transdermal, nasal, rectal, vaginal and other routes of administration that effectively result in
dispersement of the delivered agent to a single or multiple sites of intended therapeutic
action. Preferred routes of systemic delivery for the present compositions include
intravenous, intramuscular, subcutaneous and inhalational. It will be appreciated that the
exact systemic administration route for selected agents utilized in particular compositions of
the present invention will be determined in part to account for the agent's susceptibility to
metabolic transformation pathways associated with a given route of administration. For
example, peptidergic agents may be most suitably administered by routes other than oral.
MASP-2 inhibitory antibodies and polypeptides can be delivered into a subject in
need thereof by any suitable means. Methods of delivery of MASP-2 antibodies and
polypeptides include administration by oral, pulmonary, parenteral (e.g., intramuscular,
intraperitoneal, intravenous (IV) or subcutaneous injection), inhalation (such as via a fine
powder formulation), transdermal, nasal, vaginal, rectal, or sublingual routes of
administration, and can be formulated in dosage forms appropriate for each route of
administration.
By way of representative example, MASP-2 inhibitory antibodies and peptides can be
introduced into a living body by application to a bodily membrane capable of absorbing the
polypeptides, for example the nasal, gastrointestinal and rectal membranes. The
polypeptides are typically applied to the absorptive membrane in conjunction with a
permeation enhancer. (See, e.g., Lee, V.H.L., Crit. Rev. Ther. Drug Carrier Sys. 5:69, 1988;
Lee, V.H.L., J. Controlled Release 13:213, 1990; Lee, V.H.L., Ed., Peptide and Protein
Drug Delivery, Marcel Dekker, New York (1991); DeBoer, A.G., et al., J. Controlled
Release 13:241, 1990.) For example, STDHF is a synthetic derivative of fusidic acid, a
steroidal surfactant that is similar in structure to the bile salts, and has been used as a
permeation enhancer for nasal delivery. (Lee, W.A., Biopharm. 22, Nov./Dec. 1990.)
The MASP-2 inhibitory antibodies and polypeptides may be introduced in association
with another molecule, such as a lipid, to protect the polypeptides from enzymatic
degradation. For example, the covalent attachment of polymers, especially polyethylene
glycol (PEG), has been used to protect certain proteins from enzymatic hydrolysis in the
body and thus prolong half-life (Fuertges, F., et al., J. Controlled Release 11:139, 1990).
Many polymer systems have been reported for protein delivery (Bae, Y.H., et al.,
J. Controlled Release 9:271, 1989; Hori, R., et al., Pharm. Res. 6:813, 1989; Yamakawa,
I., et al., J. Pharm. Sci. 79:505, 1990; Yoshihiro, I., et al., J. Controlled Release 10:195,
1989; Asano, M., et al., J. Controlled Release 9:111, 1989; Rosenblatt, J., et al.,
J. Controlled Release 9:195, 1989; Makino, K., J. Controlled Release 12:235, 1990;
Takakura, Y., et al., J. Pharm. Sci. 78:117, 1989; Takakura, Y., et al., J. Pharm. Sci. 78:219,
1989).
Recently, liposomes have been developed with improved serum stability and
circulation half-times (see, e.g., U.S. Patent No. 5,741,516, to Webb). Furthermore, various
methods of liposome and liposome-like preparations as potential drug carriers have been
reviewed (see, e.g., U.S. Patent No. 5,567,434, to Szoka; U.S. Patent No. 5,552,157, to Yagi;
U.S. Patent No. 5,565,213, to Nakamori; U.S. Patent No. 5,738,868, to Shinkarenko; and
U.S. Patent No. 5,795,587, to Gao).
For transdermal applications, the MASP-2 inhibitory antibodies and polypeptides
may be combined with other suitable ingredients, such as carriers and/or adjuvants. There
are no limitations on the nature of such other ingredients, except that they must be
pharmaceutically acceptable for their intended administration, and cannot degrade the
activity of the active ingredients of the composition. Examples of suitable vehicles include
ointments, creams, gels, or suspensions, with or without purified collagen. The MASP-2
inhibitory antibodies and polypeptides may also be impregnated into transdermal patches,
plasters, and bandages, preferably in liquid or semi-liquid form.
The compositions of the present invention may be systemically administered on a
periodic basis at intervals determined to maintain a desired level of therapeutic effect. For
example, compositions may be administered, such as by subcutaneous injection, every two to
four weeks or at less frequent intervals. The dosage regimen will be determined by the
physician considering various factors that may influence the action of the combination of
agents. These factors will include the extent of progress of the condition being treated, the
patient's age, sex and weight, and other clinical factors. The dosage for each individual agent
will vary as a function of the MASP-2 inhibitory agent that is included in the composition, as
well as the presence and nature of any drug delivery vehicle (e.g., a sustained release
delivery vehicle). In addition, the dosage quantity may be adjusted to account for variation
in the frequency of administration and the pharmacokinetic behavior of the delivered
agent(s).
LOCAL DELIVERY
As used herein, the term "local" encompasses application of a drug in or around a site
of intended localized action, and may include for example topical delivery to the skin or
other affected tissues, ophthalmic delivery, intrathecal (IT), intracerebroventricular (ICV),
intra-articular, intracavity, intracranial or intravesicular administration, placement or
irrigation. Local administration may be preferred to enable administration of a lower dose, to
avoid systemic side effects, and for more accurate control of the timing of delivery and
concentration of the active agents at the site of local delivery. Local administration provides
a known concentration at the target site, regardless of interpatient variability in metabolism,
blood flow, etc. Improved dosage control is also provided by the direct mode of delivery.
Local delivery of a MASP-2 inhibitory agent may be achieved in the context of
surgical methods for treating a disease or condition, such as for example during procedures
such as arterial bypass surgery, atherectomy, laser procedures, ultrasonic procedures, balloon
angioplasty and stent placement. For example, a MASP-2 inhibitor can be administered to a
subject in conjunction with a balloon angioplasty procedure. A balloon angioplasty
procedure involves inserting a catheter having a deflated balloon into an artery. The deflated
balloon is positioned in proximity to the atherosclerotic plaque and is inflated such that the
plaque is compressed against the vascular wall. As a result, the balloon surface is in contact
with the layer of vascular endothelial cells on the surface of the blood vessel. The MASP-2
inhibitory agent may be attached to the balloon angioplasty catheter in a manner that permits
release of the agent at the site of the atherosclerotic plaque. The agent may be attached to the
balloon catheter in accordance with standard procedures known in the art. For example, the
agent may be stored in a compartment of the balloon catheter until the balloon is inflated, at
which point it is released into the local environment. Alternatively, the agent may be
impregnated on the balloon surface, such that it contacts the cells of the arterial wall as the
balloon is inflated. The agent may also be delivered in a perforated balloon catheter such as
those disclosed in Flugelman, M.Y., et al., Circulation 85:1110-1117, 1992. See also
published PCT Application WO 95/23161 for an exemplary procedure for attaching a
therapeutic protein to a balloon angioplasty catheter. Likewise, the MASP-2 inhibitory agent
may be included in a gel or polymeric coating applied to a stent, or may be incorporated into
the material of the stent, such that the stent elutes the MASP-2 inhibitory agent after vascular
placement.
MASP-2 inhibitory compositions used in the treatment of arthritides and other
musculoskeletal disorders may be locally delivered by intra-articular injection. Such
compositions may suitably include a sustained release delivery vehicle. As a further example
of instances in which local delivery may be desired, MASP-2 inhibitory compositions used in
the treatment of urogenital conditions may be suitably instilled intravesically or within
another urogenital structure.
COATINGS ON A MEDICAL DEVICE
MASP-2 inhibitory agents such as antibodies and inhibitory peptides may be
immobilized onto (or within) a surface of an implantable or attachable medical device. The
modified surface will typically be in contact with living tissue after implantation into an
animal body. By "implantable or attachable medical device" is intended any device that is
implanted into, or attached to, tissue of an animal body, during the normal operation of the
device (e.g., stents and implantable drug delivery devices). Such implantable or attachable
medical devices can be made from, for example, nitrocellulose, diazocellulose, glass,
polystyrene, polyvinylchloride, polypropylene, polyethylene, dextran, Sepharose, agar,
starch, nylon, stainless steel, titanium and biodegradable and/or biocompatible polymers.
Linkage of the protein to a device can be accomplished by any technique that does not
destroy the biological activity of the linked protein, for example by attaching one or both of
the N- C-terminal residues of the protein to the device. Attachment may also be made at one
or more internal sites in the protein. Multiple attachments (both internal and at the ends of
the protein) may also be used. A surface of an implantable or attachable medical device can
be modified to include functional groups (e.g., carboxyl, amide, amino, ether, hydroxyl,
cyano, nitrido, sulfanamido, acetylinic, epoxide, silanic, anhydric, succinimic, azido) for
protein immobilization thereto. Coupling chemistries include, but are not limited to, the
formation of esters, ethers, amides, azido and sulfanamido derivatives, cyanate and other
linkages to the functional groups available on MASP-2 antibodies or inhibitory peptides.
MASP-2 antibodies or inhibitory fragments can also be attached non-covalently by the
addition of an affinity tag sequence to the protein, such as GST (D.B. Smith and K.S.
Johnson, Gene 67:31, 1988), polyhistidines (E. Hochuli et al., J. Chromatog. 411:77, 1987),
or biotin. Such affinity tags may be used for the reversible attachment of the protein to a
device.
Proteins can also be covalently attached to the surface of a device body, for example,
by covalent activation of the surface of the medical device. By way of representative
example, matricellular protein(s) can be attached to the device body by any of the following
pairs of reactive groups (one member of the pair being present on the surface of the device
body, and the other member of the pair being present on the matricellular protein(s)):
hydroxyl/carboxylic acid to yield an ester linkage; hydroxyl/anhydride to yield an ester
linkage; hydroxyl/isocyanate to yield a urethane linkage. A surface of a device body that
does not possess useful reactive groups can be treated with radio-frequency discharge plasma
(RFGD) etching to generate reactive groups in order to allow deposition of matricellular
protein(s) (e.g., treatment with oxygen plasma to introduce oxygen-containing groups;
treatment with propyl amino plasma to introduce amine groups).
MASP-2 inhibitory agents comprising nucleic acid molecules such as antisense,
RNAi-or DNA-encoding peptide inhibitors can be embedded in porous matrices attached to a
device body. Representative porous matrices useful for making the surface layer are those
prepared from tendon or dermal collagen, as may be obtained from a variety of commercial
sources (e.g., Sigma and Collagen Corporation), or collagen matrices prepared as described
in U.S. Patent Nos. 4,394,370, to Jefferies, and 4,975,527, to Koezuka. One collagenous
material is termed UltraFiberTM and is obtainable from Norian Corp. (Mountain View,
California).
Certain polymeric matrices may also be employed if desired, and include acrylic ester
polymers and lactic acid polymers, as disclosed, for example, in U.S. Patent Nos. 4,526,909
and 4,563,489, to Urist. Particular examples of useful polymers are those of orthoesters,
anhydrides, propylene-cofumarates, or a polymer of one or more α-hydroxy carboxylic acid
monomers, (e.g., α-hydroxy acetic acid (glycolic acid) and/or α-hydroxy propionic acid
(lactic acid)).
TREATMENT REGIMENS
In prophylactic applications, the pharmaceutical compositions are administered to a
subject susceptible to, or otherwise at risk of, a condition associated with MASPdependent
complement activation in an amount sufficient to eliminate or reduce the risk of developing
symptoms of the condition. In therapeutic applications, the pharmaceutical compositions are
administered to a subject suspected of, or already suffering from, a condition associated with
MASPdependent complement activation in a therapeutically effective amount sufficient to
relieve, or at least partially reduce, the symptoms of the condition. In both prophylactic and
therapeutic regimens, compositions comprising MASP-2 inhibitory agents may be
administered in several dosages until a sufficient therapeutic outcome has been achieved in
the subject. Application of the MASP-2 inhibitory compositions of the present invention
may be carried out by a single administration of the composition, or a limited sequence of
administrations, for treatment of an acute condition, e.g., reperfusion injury or other
traumatic injury. Alternatively, the composition may be administered at periodic intervals
over an extended period of time for treatment of chronic conditions, e.g., arthritides or
psoriasis.
The methods and compositions of the present invention may be used to inhibit
inflammation and related processes that typically result from diagnostic and therapeutic
medical and surgical procedures. To inhibit such processes, the MASP-2 inhibitory
composition of the present invention may be applied periprocedurally. As used herein
"periprocedurally" refers to administration of the inhibitory composition preprocedurally
and/or intraprocedurally and/or postprocedurally, i.e., before the procedure, before and
during the procedure, before and after the procedure, before, during and after the procedure,
during the procedure, during and after the procedure, or after the procedure. Periprocedural
application may be carried out by local administration of the composition to the surgical or
procedural site, such as by injection or continuous or intermittent irrigation of the site or by
systemic administration. Suitable methods for local perioperative delivery of MASP-2
inhibitory agent solutions are disclosed in US Patent Nos. 6,420,432 to Demopulos
and 6,645,168 to Demopulos. Suitable methods for local delivery of chondroprotective
compositions including MASP-2 inhibitory agent(s) are disclosed in International PCT
Patent Application WO 01/07067 A2. Suitable methods and compositions for targeted
systemic delivery of chondroprotective compositions including MASP-2 inhibitory agent(s)
are disclosed in International PCT Patent Application WO 03/063799 A2.
In one aspect of the invention, the pharmaceutical compositions are administered to a
subject susceptible to, or otherwise at risk of, PNH in an amount sufficient to eliminate or
reduce the risk of developing symptoms of the condition. In therapeutic applications, the
pharmaceutical compositions are administered to a subject suspected of, or already suffering
from, PNH in a therapeutically effective amount sufficient to relieve, or at least partially
reduce, the symptoms of the condition.
In one embodiment, the subject's red blood cells are opsonized by fragments of C3 in
the absence of the composition, and administration of the composition comprising a MASP-2
inhibitory agent to the subject increases the survival of red blood cells in the subject. In one
embodiment, the subject exhibits one or more symptoms in the absence of the composition
selected from the group consisting of (i) below normal levels of hemoglobin, (ii) below
normal levels of platelets; (iii) above normal levels of reticulocytes, and (iv) above normal
levels of bilirubin, and administration of the composition to the subject improves at least one
or more of the symptoms, resulting in (i) increased, normal, or nearly normal levels of
hemoglobin (ii) increased, normal or nearly normal levels of platelets, (iii) decreased, normal
or nearly normal levels of reticulocytes, and/or (iv) decreased, normal or nearly normal
levels of bilirubin.
In both prophylactic and therapeutic regimens, compositions comprising MASP-2
inhibitory agents may be administered in several dosages until a sufficient therapeutic
outcome has been achieved in the subject. In one embodiment of the invention, the MASP-2
inhibitory agent comprises an anti-MASP-2 antibody, which suitably may be administered to
an adult patient (e.g., an average adult weight of 70 kg) in a dosage of from 0.1 mg to 10,000
mg, more suitably from 1.0 mg to 5,000 mg, more suitably 10.0 mg to 2,000 mg, more
suitably 10.0 mg to 1,000 mg and still more suitably from 50.0 mg to 500 mg. For pediatric
patients, dosage can be adjusted in proportion to the patient’s weight. Application of the
MASP-2 inhibitory compositions of the present invention may be carried out by a single
administration of the composition, or a limited sequence of administrations, for treatment of
PNH. Alternatively, the composition may be administered at periodic intervals such as daily,
biweekly, weekly, every other week, monthly or bimonthly over an extended period of time
for treatment of PNH.
In some embodiments, the subject suffering from PNH has previously undergone, or
is currently undergoing treatment with a terminal complement inhibitor that inhibits cleavage
of complement protein C5. In some embodiments, the method comprises administering to
the subject a composition of the invention comprising a MASP-2 inhibitor and further
administering to the subject a terminal complement inhibitor that inhibits cleavage of
complement protein C5. In some embodiments, the terminal complement inhibitor is a
humanized anti-C5 antibody or antigen-binding fragment thereof. In some embodiments, the
terminal complement inhibitor is eculizumab.
In one aspect of the invention, the pharmaceutical compositions are administered to a
subject susceptible to, or otherwise at risk of, aHUS in an amount sufficient to eliminate or
reduce the risk of developing symptoms of the condition. In therapeutic applications, the
pharmaceutical compositions are administered to a subject suspected of, or already suffering
from, aHUS in a therapeutically effective amount sufficient to relieve, or at least partially
reduce, the symptoms of the condition. In one aspect of the invention, prior to
administration, the subject may be examined to determine whether the subject exhibits one or
more symptoms of aHUS, including (i) anemia, (ii) thrombocytopenia (iii) renal
insufficiency and (iv) rising creatinine, and the composition of the present invention is then
administered in an effective amount and for a sufficient time period to improve these
symptom(s).
In another aspect of the invention, the MASP-2 inhibitory compositions of the present
invention may be used to prophylactically treat a subject that has an elevated risk of
developing aHUS and thereby reduce the likelihood that the subject will deliver aHUS. The
presence of a genetic marker in the subject known to be associated with aHUS is first
determined by performing a genetic screening test on a sample obtained from the subject and
identifying the presence of at least one genetic marker associated with aHUS, complement
factor H (CFH), factor I (CFI), factor B (CFB), membrane cofactor CD46, C3, complement
factor H-related protein (CFHR1), anticoagulant protein thrombodulin (THBD), complement
factor H-related protein 3 (CFHR3) or complement factor H-related protein 4 (CFHR4). The
subject is then periodically monitored (e.g., monthly, quarterly, twice annually or annually)
to determine the presence or absence of at least one symptom of aHUS, such as anemia,
thrombocytopenia, renal insufficiency and rising creatinine. Upon the determination of the
presence of at least one of these symptoms, the subject can be administered an amount of a
MASP-2 inhibitory agent effective to inhibit MASP-2 dependent complement activation, in
an effective amount and for a sufficient time period to improve said one or more symptoms.
In a still further aspect of the present invention, a subject at increased risk of developing
aHUS due to having been screened and determined to have one of the genetic markers
associated with aHUS may be monitored for the occurrence of an event associated with
triggering aHUS clinical symptoms, including drug exposure, infection (e.g., bacterial
infection), malignancy, injury, organ or tissue transplant and pregnancy.
In a still further aspect of the present invention, a composition comprising an amount
of a MASP-2 inhibitory agent effective to inhibit MASP-2 dependent complement activation
can be administered to a suffering from or at risk of developing atypical hemolytic uremic
syndrome (aHUS) secondary to an infection. For example, a patient suffering from or at risk
of developing non-enteric aHUS associated with an S. pneumonia infection may be treated
with the compositions of the present invention.
In a still further aspect of the present invention, a subject suffering from aHUS may
initially be treated with a MASP-2 inhibitory composition of the present invention that is
administered through a catheter line, such as an intravenous catheter line or a subcutaneous
catheter line, for a first period of time such as one hour, twelve hours, one day, two days or
three days. The subject may then be treated for a second period of time with the MASP-2
inhibitory composition administered through regular subcutaneous injections, such as daily,
biweekly, weekly, every other week, monthly or bimonthly, injections.
In a still further aspect of the present invention, a MASP-2 inhibitory composition of
the present invention may be administered to a subject suffering from aHUS in the absence
of plasmapheresis (i.e., a subject whose aHUS symptoms have not been treated with
plasmapheresis and are not treated with plasmapheresis at the time of treatment with the
MASP-2 inhibitory composition), to avoid the potential complications of plasmaphersis
including hemorrhage, infection, and exposure to disorders and/or allergies inherent in the
plasma donor, or in a subject otherwise averse to plasmapheresis, or in a setting where
plasmapheresis is unavailable.
In a still further aspect of the present invention, a MASP-2 inhibitory composition of
the present invention may be administered to a subject suffering from aHUS coincident with
treating the patient with plasmapheresis. For example, a subject receiving plasmapheresis
treatment can then be administered the MASP-2 inhibitory composition following or
alternating with plasma exchange.
In a still further aspect of the present invention, a subject suffering from or at risk of
developing aHUS and being treated with a MASP-2 inhibitory composition of the present
invention can be monitored by periodically determining, such as every twelve hours or on a
daily basis, the level of at least one complement factor, wherein the determination of a
reduced level of the at least one complement factor in comparison to a standard value or to a
healthy subject is indicative of the need for continued treatment with the composition.
In both prophylactic and therapeutic regimens, compositions comprising MASP-2
inhibitory agents may be administered in several dosages until a sufficient therapeutic
outcome has been achieved in the subject. In one embodiment of the invention, the MASP-2
inhibitory agent comprises an anti-MASP-2 antibody, which suitably may be administered to
an adult patient (e.g., an average adult weight of 70 kg) in a dosage of from 0.1 mg to 10,000
mg, more suitably from 1.0 mg to 5,000 mg, more suitably 10.0 mg to 2,000 mg, more
suitably 10.0 mg to 1,000 mg and still more suitably from 50.0 mg to 500 mg. For pediatric
patients, dosage can be adjusted in proportion to the patient’s weight. Application of the
MASP-2 inhibitory compositions of the present invention may be carried out by a single
administration of the composition, or a limited sequence of administrations, for treatment of
aHUS. Alternatively, the composition may be administered at periodic intervals, such as
daily, biweekly, weekly, every other week, monthly or bimonthly, over an extended period of
time for treatment of aHUS.
In some embodiments, the subject suffering from aHUS has previously undergone, or
is currently undergoing treatment with a terminal complement inhibitor that inhibits cleavage
of complement protein C5. In some embodiments, the method comprises administering to
the subject a composition of the invention comprising a MASP-2 inhibitor and further
administering to the subject a terminal complement inhibitor that inhibits cleavage of
complement protein C5. In some embodiments, the terminal complement inhibitor is a
humanized anti-C5 antibody or antigen-binding fragment thereof. In some embodiments, the
terminal complement inhibitor is eculizumab.
In one aspect of the invention, the pharmaceutical compositions are administered to a
subject susceptible to, or otherwise at risk of, HUS in an amount sufficient to eliminate or
reduce the risk of developing symptoms of the condition. In therapeutic applications, the
pharmaceutical compositions are administered to a subject suspected of, or already suffering
from, HUS in a therapeutically effective amount sufficient to relieve, or at least partially
reduce, the symptoms of the condition.
In another aspect of the present invention, the likelihood of developing impaired renal
function in a subject at risk for developing HUS can be reduced by administering to the
subject a MASP-2 inhibitory composition of the present invention in an amount effective to
inhibit MASP-2 dependent complement activation. For example, a subject at risk for
developing HUS and to be treated with a MASP-2 inhibitory composition of the present
invention may exhibit one or more symptoms associated with HUS, including diarrhea, a
hematocrit level of less than 30% with smear evidence of intravascular erythrocyte
destruction, thrombocytopenia and rising creatinine levels. As a further example, a subject at
risk for developing HUS and to be treated with the MASP-2 inhibitory compositions of the
present invention may be infected with E. coli, shigella or salmonella. Such subjects infected
with E. coli, shigella or salmonella may be treated with a MASP-2 inhibitory composition of
the present invention concurrent with antibiotic treatment, or alternately may be treated with
a MASP-2 inhibitory composition without concurrent treatment with an antibiotic,
particularly for enterogenic E. coli for which antibiotic treatment is contra-indicated. A
subject infected with enterogenic E. coli that has been treated with an antibiotic may be at
elevated risk of developing HUS, and may be suitably treated with a MASP-2 inhibitory
composition of the present invention to reduce that risk. A subject infected with enterogenic
E. coli may be treated for a first period of time with a MASP-2 inhibitory composition of the
present invention in the absence of an antibiotic and then for a second period of time with
both a MASP-2 inhibitory composition of the present invention and an antibiotic.
In a still further aspect of the present invention, a subject suffering from HUS may
initially be treated with a MASP-2 inhibitory composition of the present invention that is
administered through a catheter line, such as an intravenous catheter line or a subcutaneous
catheter line, for a first period of time such as one hour, twelve hours, one day, two days or
three days. The subject may then be treated for a second period of time with the MASP-2
inhibitory composition administered through regular subcutaneous injections, such as daily,
biweekly, weekly, every other week, monthly or bimonthly, injections.
In a still further aspect of the present invention, a MASP-2 inhibitory composition of
the present invention may be administered to a subject suffering from HUS in the absence of
plasmapheresis (i.e., a subject whose HUS symptoms have not been treated with
plasmapheresis and are not treated with plasmapheresis at the time of treatment with the
MASP-2 inhibitory composition), to avoid the potential complications of plasmaphersis
including hemorrhage, infection, and exposure to disorders and/or allergies inherent in the
plasma donor, or in a subject otherwise averse to plasmapheresis, or in a setting where
plasmapheresis is unavailable.
In a still further aspect of the present invention, a MASP-2 inhibitory composition of
the present invention may be administered to a subject suffering from HUS coincident with
treating the patient with plasmapheresis. For example, a subject receiving plasmapheresis
treatment can then be administered the MASP-2 inhibitory composition following or
alternating with plasma exchange.
In a still further aspect of the present invention, a subject suffering from or at risk of
developing HUS and being treated with a MASP-2 inhibitory composition of the present
invention can be monitored by periodically determining, such as every twelve hours or on a
daily basis, the level of at least one complement factor, wherein the determination of a
reduced level of the at least one complement factor in comparison to a standard value or to a
healthy subject is indicative of the need for continued treatment with the composition.
In both prophylactic and therapeutic regimens, compositions comprising MASP-2
inhibitory agents may be administered in several dosages until a sufficient therapeutic
outcome has been achieved in the subject. In one embodiment of the invention, the MASP-2
inhibitory agent comprises an anti-MASP-2 antibody, which suitably may be administered to
an adult patient (e.g., an average adult weight of 70 kg) in a dosage of from 0.1 mg to 10,000
mg, more suitably from 1.0 mg to 5,000 mg, more suitably 10.0 mg to 2,000 mg, more
suitably 10.0 mg to 1,000 mg and still more suitably from 50.0 mg to 500 mg. For pediatric
patients, dosage can be adjusted in proportion to the patient’s weight. Application of the
MASP-2 inhibitory compositions of the present invention may be carried out by a single
administration of the composition, or a limited sequence of administrations, for treatment of
HUS. Alternatively, the composition may be administered at periodic intervals, such as
daily, biweekly, weekly, every other week, monthly or bimonthly, over an extended period of
time for treatment of HUS.
In some embodiments, the subject suffering from HUS has previously undergone, or
is currently undergoing treatment with a terminal complement inhibitor that inhibits cleavage
of complement protein C5. In some embodiments, the method comprises administering to
the subject a composition of the invention comprising a MASP-2 inhibitor and further
administering to the subject a terminal complement inhibitor that inhibits cleavage of
complement protein C5. In some embodiments, the terminal complement inhibitor is a
humanized anti-C5 antibody or antigen-binding fragment thereof. In some embodiments, the
terminal complement inhibitor is eculizumab.
In one aspect of the invention, the pharmaceutical compositions are administered to a
subject susceptible to, or otherwise at risk of, TTP in an amount sufficient to eliminate or
reduce the risk of developing symptoms of the condition. In therapeutic applications, the
pharmaceutical compositions are administered to a subject suspected of, or already suffering
from, TTP in a therapeutically effective amount sufficient to relieve, or at least partially
reduce, the symptoms of the condition.
In another aspect of the present invention, a subject exhibiting one or more of the
symptoms of TTP, including central nervous system involvement, thrombocytopenia, severe
cardiac involvement, severe pulmonary involvement, gastro-intestinal infarction and
gangrene, may be treated with a MASP-2 inhibitory composition of the present invention. In
another aspect of the present invention, a subject determined to have a depressed level of
ADAMTS13 and also testing positive for the presence of an inhibitor of (i.e., an antibody)
ADAMTS13 may be treated with a MASP-2 inhibitory composition of the present invention.
In a still further aspect of the present invention, a subject testing positive for the presence of
an inhibitor of ADAMTS13 may be treated with an immunosupressant (e.g., corticosteroids,
rituxan, or cyclosporine) concurrently with treatment with a MASP-2 inhibitory composition
of the present invention. In a still further aspect of the present invention, a subject
determined to have a reduced level of ADAMTS13 and testing positive for the presence of
an inhibitor of ADAMTS13 may be treated with ADAMTS13 concurrently with treatment
with a MASP-2 inhibitory composition of the present invention.
In a still further aspect of the present invention, a subject suffering from TTP may
initially be treated with a MASP-2 inhibitory composition of the present invention that is
administered through a catheter line, such as an intravenous catheter line or a subcutaneous
catheter line, for a first period of time such as one hour, twelve hours, one day, two days or
three days. The subject may then be treated for a second period of time with the MASP-2
inhibitory composition administered through regular subcutaneous injections, such as daily,
biweekly, weekly, every other week, monthly or bimonthly, injections.
In a still further aspect of the present invention, a MASP-2 inhibitory composition of
the present invention may be administered to a subject suffering from HUS in the absence of
plasmapheresis (i.e., a subject whose TTP symptoms have not been treated with
plasmapheresis and are not treated with plasmapheresis at the time of treatment with the
MASP-2 inhibitory composition), to avoid the potential complications of plasmaphersis
including hemorrhage, infection, and exposure to disorders and/or allergies inherent in the
plasma donor, or in a subject otherwise averse to plasmapheresis, or in a setting where
plasmapheresis is unavailable.
In a still further aspect of the present invention, a MASP-2 inhibitory composition of
the present invention may be administered to a subject suffering from TTP coincident with
treating the patient with plasmapheresis. For example, a subject receiving plasmapheresis
treatment can then be administered the MASP-2 inhibitory composition following or
alternating with plasma exchange.
In a still further aspect of the present invention, a subject suffering from refractory
TTP, i.e., symptoms of TTP that have not responded adequately to other treatment such as
plasmapheresis, may be treated with a MASP-2 inhibitory composition of the present
invention, with or without additional plasmapheresis.
In a still further aspect of the present invention, a subject suffering from or at risk of
developing TTP and being treated with a MASP-2 inhibitory composition of the present
invention can be monitored by periodically determining, such as every twelve hours or on a
daily basis, the level of at least one complement factor, wherein the determination of a
reduced level of the at least one complement factor in comparison to a standard value or to a
healthy subject is indicative of the need for continued treatment with the composition.
In both prophylactic and therapeutic regimens, compositions comprising MASP-2
inhibitory agents may be administered in several dosages until a sufficient therapeutic
outcome has been achieved in the subject. In one embodiment of the invention, the MASP-2
inhibitory agent comprises an anti-MASP-2 antibody, which suitably may be administered to
an adult patient (e.g., an average adult weight of 70 kg) in a dosage of from 0.1 mg to 10,000
mg, more suitably from 1.0 mg to 5,000 mg, more suitably 10.0 mg to 2,000 mg, more
suitably 10.0 mg to 1,000 mg and still more suitably from 50.0 mg to 500 mg. For pediatric
patients, dosage can be adjusted in proportion to the patient’s weight. Application of the
MASP-2 inhibitory compositions of the present invention may be carried out by a single
administration of the composition, or a limited sequence of administrations, for treatment of
TTP. Alternatively, the composition may be administered at periodic intervals, such as daily,
biweekly, weekly, every other week, monthly or bimonthly, over an extended period of time
for treatment of TTP.
In some embodiments, the subject suffering from TTP has previously undergone, or
is currently undergoing treatment with a terminal complement inhibitor that inhibits cleavage
of complement protein C5. In some embodiments, the method comprises administering to
the subject a composition of the invention comprising a MASP-2 inhibitor and further
administering to the subject a terminal complement inhibitor that inhibits cleavage of
complement protein C5. In some embodiments, the terminal complement inhibitor is a
humanized anti-C5 antibody or antigen-binding fragment thereof. In some embodiments, the
terminal complement inhibitor is eculizumab.
In one aspect of the invention, the pharmaceutical compositions are administered to a
subject susceptible to, or otherwise at risk of, cold aggultinin disease or cryoglobulinemia in
an amount sufficient to eliminate or reduce the risk of developing symptoms of the condition.
In therapeutic applications, the pharmaceutical compositions are administered to a subject
suspected of, or already suffering from, cold aggultinin disease or cryoglobulinemia in a
therapeutically effective amount sufficient to relieve, or at least partially reduce, the
symptoms of the condition.
In a still further aspect of the present invention, a subject suffering from or at risk of
developing cold aggultinin disease or cryoglobulinemia and being treated with a MASP-2
inhibitory composition of the present invention can be monitored by periodically
determining, such as every twelve hours or on a daily basis, the level of at least one
complement factor, wherein the determination of a reduced level of the at least one
complement factor in comparison to a standard value or to a healthy subject is indicative of
the need for continued treatment with the composition.
In both prophylactic and therapeutic regimens, compositions comprising MASP-2
inhibitory agents may be administered in several dosages until a sufficient therapeutic
outcome has been achieved in the subject. In one embodiment of the invention, the MASP-2
inhibitory agent comprises an anti-MASP-2 antibody, which suitably may be administered to
an adult patient (e.g., an average adult weight of 70 kg) in a dosage of from 0.1 mg to 10,000
mg, more suitably from 1.0 mg to 5,000 mg, more suitably 10.0 mg to 2,000 mg, more
suitably 10.0 mg to 1,000 mg and still more suitably from 50.0 mg to 500 mg. For pediatric
patients, dosage can be adjusted in proportion to the patient’s weight. Application of the
MASP-2 inhibitory compositions of the present invention may be carried out by a single
administration of the composition, or a limited sequence of administrations, for treatment of
cold aggultinin disease or cryoglobulinemia. Alternatively, the composition may be
administered at periodic intervals, such as daily, biweekly, weekly, every other week,
monthly or bimonthly, over an extended period of time for treatment of cold aggultinin
disease or cryoglobulinemia.
In some embodiments, the subject suffering from cold aggultinin disease or
cryoglobulinemia has previously undergone, or is currently undergoing treatment with a
terminal complement inhibitor that inhibits cleavage of complement protein C5. In some
embodiments, the method comprises administering to the subject a composition of the
invention comprising a MASP-2 inhibitor and further administering to the subject a terminal
complement inhibitor that inhibits cleavage of complement protein C5. In some
embodiments, the terminal complement inhibitor is a humanized anti-C5 antibody or antigenbinding fragment thereof. In some embodiments, the terminal complement inhibitor is
eculizumab.
In one aspect of the invention, the pharmaceutical compositions are administered to a
subject susceptible to, or otherwise at risk of, glaucoma in an amount sufficient to eliminate
or reduce the risk of developing symptoms of the condition. In therapeutic applications, the
pharmaceutical compositions are administered to a subject suspected of, or already suffering
from, glaucoma in a therapeutically effective amount sufficient to relieve, or at least partially
reduce, the symptoms of the condition.
In a still further aspect of the present invention, a subject suffering from or at risk of
developing glaucoma and being treated with a MASP-2 inhibitory composition of the present
invention can be monitored by periodically determining, such as every twelve hours or on a
daily basis, the level of at least one complement factor, wherein the determination of a
reduced level of the at least one complement factor in comparison to a standard value or to a
healthy subject is indicative of the need for continued treatment with the composition.
In both prophylactic and therapeutic regimens, compositions comprising MASP-2
inhibitory agents may be administered in several dosages until a sufficient therapeutic
outcome has been achieved in the subject. In one embodiment of the invention, the MASP-2
inhibitory agent comprises an anti-MASP-2 antibody, which suitably may be administered to
an adult patient (e.g., an average adult weight of 70 kg) in a dosage of from 0.1 mg to 10,000
mg, more suitably from 1.0 mg to 5,000 mg, more suitably 10.0 mg to 2,000 mg, more
suitably 10.0 mg to 1,000 mg and still more suitably from 50.0 mg to 500 mg. For pediatric
patients, dosage can be adjusted in proportion to the patient’s weight. Application of the
MASP-2 inhibitory compositions of the present invention may be carried out by a single
administration of the composition, or a limited sequence of administrations, for treatment of
glaucoma. Alternatively, the composition may be administered at periodic intervals, such as
daily, biweekly, weekly, every other week, monthly or bimonthly, over an extended period of
time for treatment of cold aggultinin disease.
In some embodiments, the subject suffering from glaucoma has previously
undergone, or is currently undergoing treatment with a terminal complement inhibitor that
inhibits cleavage of complement protein C5. In some embodiments, the method comprises
administering to the subject a composition of the invention comprising a MASP-2 inhibitor
and further administering to the subject a terminal complement inhibitor that inhibits
cleavage of complement protein C5. In some embodiments, the terminal complement
inhibitor is a humanized anti-C5 antibody or antigen-binding fragment thereof. In some
embodiments, the terminal complement inhibitor is eculizumab.
In one aspect of the invention, the pharmaceutical compositions are administered to a
subject suffering from or at risk of developing acute radiation syndrome, in an amount
sufficient to eliminate or reduce the risk of developing symptoms of the condition. In
therapeutic applications, the pharmaceutical compositions are administered to a subject
suspected of, or already suffering from, acute radiation syndrome in a therapeutically
effective amount sufficient to relieve, or at least partially reduce, the symptoms of the
condition. A subject may be treated with a MASP-2 inhibitory composition of the present
invention prior to or after exposure to radiation, such as radiation exposure for the treatment
of cancerous conditions, while cleaning up a site contaminated with radiation, in working
with radioactive materials in an energy generation plant or laboratory, or due to radiation
exposure resulting from a nuclear accident, terrorist action or warfare. In one embodiment of
the present invention, the MASP-2 inhibitory composition is administered within 24 to 48
hours after radiation exposure.
In a still further aspect of the present invention, a subject suffering from or at risk of
developing acute radiation syndrome and being treated with a MASP-2 inhibitory
composition of the present invention can be monitored by periodically determining, such as
every twelve hours or on a daily basis, the level of at least one complement factor, wherein
the determination of a reduced level of the at least one complement factor in comparison to a
standard value or to a healthy subject is indicative of the need for continued treatment with
the composition.
In both prophylactic and therapeutic regimens, compositions comprising MASP-2
inhibitory agents may be administered in several dosages until a sufficient therapeutic
outcome has been achieved in the subject. In one embodiment of the invention, the MASP-2
inhibitory agent comprises an anti-MASP-2 antibody, which suitably may be administered to
an adult patient (e.g., an average adult weight of 70 kg) in a dosage of from 0.1 mg to 10,000
mg, more suitably from 1.0 mg to 5,000 mg, more suitably 10.0 mg to 2,000 mg, more
suitably 10.0 mg to 1,000 mg and still more suitably from 50.0 mg to 500 mg. For pediatric
patients, dosage can be adjusted in proportion to the patient’s weight. Application of the
MASP-2 inhibitory compositions of the present invention may be carried out by a single
administration of the composition, or a limited sequence of administrations, for treatment of
glaucoma. Alternatively, the composition may be administered at periodic intervals, such as
daily, biweekly, weekly, every other week, monthly or bimonthly, over an extended period of
time for treatment of acute radiation syndrome.
In some embodiments, the subject suffering from acute radiation syndrome has
previously undergone, or is currently undergoing treatment with a terminal complement
inhibitor that inhibits cleavage of complement protein C5. In some embodiments, the
method comprises administering to the subject a composition of the invention comprising a
MASP-2 inhibitor and further administering to the subject a terminal complement inhibitor
that inhibits cleavage of complement protein C5. In some embodiments, the terminal
complement inhibitor is a humanized anti-C5 antibody or antigen-binding fragment thereof.
In some embodiments, the terminal complement inhibitor is eculizumab.
VI. EXAMPLES
The following examples merely illustrate the best mode now contemplated for
practicing the invention, but should not be construed to limit the invention. All literature
citations herein are expressly incorporated by reference.
EXAMPLE 1
This example describes the generation of a mouse strain deficient in MASP-2
(MASP/-) but sufficient of MAp19 (MAp19+/+).
Materials and Methods: The targeting vector pKO-NTKV 1901 was designed to
disrupt the three exons coding for the C-terminal end of murine MASP-2, including the exon
that encodes the serine protease domain, as shown in FIGURE 3. PKO-NTKV 1901 was
used to transfect the murine ES cell line E14.1a (SV129 Ola). Neomycin-resistant and
Thymidine Kinase-sensitive clones were selected. 600 ES clones were screened and, of
these, four different clones were identified and verified by southern blot to contain the
expected selective targeting and recombination event as shown in FIGURE 3. Chimeras
were generated from these four positive clones by embryo transfer. The chimeras were then
backcrossed in the genetic background C57/BL6 to create transgenic males. The transgenic
males were crossed with females to generate F1s with 50% of the offspring showing
heterozygosity for the disrupted MASP-2 gene. The heterozygous mice were intercrossed to
generate homozygous MASP-2 deficient offspring, resulting in heterozygous and wild-type
mice in the ration of 1:2:1, respectively.
Results and Phenotype: The resulting homozygous MASP/- deficient mice were
found to be viable and fertile and were verified to be MASP-2 deficient by southern blot to
confirm the correct targeting event, by Northern blot to confirm the absence of MASP-2
mRNA, and by Western blot to confirm the absence of MASP-2 protein (data not shown).
The presence of MAp19 mRNA and the absence of MASP-2 mRNA were further confirmed
using time-resolved RT-PCR on a LightCycler machine. The MASP/- mice do continue
to express MAp19, MASP-1, and MASP-3 mRNA and protein as expected (data not shown).
The presence and abundance of mRNA in the MASP/- mice for Properdin, Factor B,
Factor D, C4, C2, and C3 was assessed by LightCycler analysis and found to be identical to
that of the wild-type littermate controls (data not shown). The plasma from homozygous
MASP/- mice is totally deficient of lectin-pathway-mediated complement activation as
further described in Example 2.
Generation of a MASP/- strain on a pure C57BL6 Background: The MASP/-
mice were back-crossed with a pure C57BL6 line for nine generations prior to use of the
MASP/- strain as an experimental animal model.
A transgenic mouse strain that is murine MASP/-, MAp19+/+ and that expresses a
human MASP-2 transgene (a murine MASP-2 knock-out and a human MASP-2 knock-in)
was also generated as follows:
Materials and Methods: A minigene encoding human MASP-2 called "mini
hMASP-2" (SEQ ID NO:49) as shown in FIGURE 4 was constructed which includes the
promoter region of the human MASP 2 gene, including the first 3 exons (exon 1 to exon 3)
followed by the cDNA sequence that represents the coding sequence of the following
8 exons, thereby encoding the full-length MASP-2 protein driven by its endogenous
promoter. The mini hMASP-2 construct was injected into fertilized eggs of MASP/- in
order to replace the deficient murine MASP 2 gene by transgenically expressed human
MASP-2.
EXAMPLE 2
This example demonstrates that MASP-2 is required for complement activation via
the lectin pathway.
Methods and Materials:
Lectin pathway specific C4 Cleavage Assay: A C4 cleavage assay has been
described by Petersen, et al., J. Immunol. Methods 257:107 (2001) that measures lectin
pathway activation resulting from lipoteichoic acid (LTA) from S. aureus, which binds
L-ficolin. The assay described by Petersen et al., (2001) was adapted to measure lectin
pathway activation via MBL by coating the plate with LPS and mannan or zymosan prior to
adding serum from MASP-2 -/- mice as described below. The assay was also modified to
remove the possibility of C4 cleavage due to the classical pathway. This was achieved by
using a sample dilution buffer containing 1 M NaCl, which permits high affinity binding of
lectin pathway recognition components to their ligands but prevents activation of
endogenous C4, thereby excluding the participation of the classical pathway by dissociating
the C1 complex. Briefly described, in the modified assay serum samples (diluted in high salt
(1 M NaCl) buffer) are added to ligand-coated plates, followed by the addition of a constant
amount of purified C4 in a buffer with a physiological concentration of salt. Bound
recognition complexes containing MASP-2 cleave the C4, resulting in C4b deposition.
Assay Methods:
1) Nunc Maxisorb microtiter plates (Maxisorb, Nunc, Cat. No. 442404, Fisher
Scientific) were coated with 1 µg/ml mannan (M7504 Sigma) or any other ligand (e.g., such
as those listed below) diluted in coating buffer (15 mM Na2CO3, 35 mM NaHCO3, pH 9.6).
The following reagents were used in the assay:
a. mannan (1 µg/well mannan (M7504 Sigma) in 100 µl coating buffer):
b. zymosan (1 µg/well zymosan (Sigma) in 100 µl coating buffer);
c. LTA (1µg/well in 100 µl coating buffer or 2 µg/well in 20 µl methanol)
d. 1 µg of the H-ficolin specific Mab 4H5 in coating buffer
e. PSA from Aerococcus viridans (2 µg/well in 100 µl coating buffer)
f. 100 µl/well of formalin-fixed S. aureus DSM20233 (OD550=0.5) in coating
buffer.
2) The plates were incubated overnight at 4°C.
3) After overnight incubation, the residual protein binding sites were saturated
by incubated the plates with 0.1% HSA-TBS blocking buffer (0.1% (w/v) HSA in 10 mM
Tris-CL, 140 mM NaCl, 1.5 mM NaN3, pH 7.4) for 1-3 hours, then washing the plates 3X
with TBS/tween/Ca2+ (TBS with 0.05% Tween 20 and 5 mM CaCl2, 1 mM MgCl2,
pH 7.4).
4) Serum samples to be tested were diluted in MBL-binding buffer (1 M NaCl)
and the diluted samples were added to the plates and incubated overnight at 4°C. Wells
receiving buffer only were used as negative controls.
) Following incubation overnight at 4°C, the plates were washed 3X with
TBS/tween/Ca2+. Human C4 (100 µl/well of 1 µg/ml diluted in BBS (4 mM barbital,
145 mM NaCl, 2 mM CaCl2, 1 mM MgCl2, pH 7.4)) was then added to the plates and
incubated for 90 minutes at 37°C. The plates were washed again 3X with TBS/tween/Ca2+.
6) C4b deposition was detected with an alkaline phosphatase-conjugated chicken
anti-human C4c (diluted 1:1000 in TBS/tween/Ca2+), which was added to the plates and
incubated for 90 minutes at room temperature. The plates were then washed again 3X with
TBS/tween/Ca2+.
7) Alkaline phosphatase was detected by adding 100 µl of p-nitrophenyl
phosphate substrate solution, incubating at room temperature for 20 minutes, and reading
the OD405 in a microtiter plate reader.
Results: FIGURES 5A-B show the amount of C4b deposition on mannan
(FIGURE 5A) and zymosan (FIGURE 5B) in serum dilutions from MASP-2+/+ (crosses),
MASP-2+/- (closed circles) and MASP/- (closed triangles). FIGURE 5C shows the
relative C4 convertase activity on plates coated with zymosan (white bars) or mannan
(shaded bars) from MASP/+ mice (n=5) and MASP/- mice (n=4) relative to wild-type
mice (n=5) based on measuring the amount of C4b deposition normalized to wild-type
serum. The error bars represent the standard deviation. As shown in FIGURES 5A-C,
plasma from MASP/- mice is totally deficient in lectin-pathway-mediated complement
activation on mannan and on zymosan coated plates. These results clearly demonstrate that
MASP-2 is an effector component of the lectin pathway.
Recombinant MASP-2 reconstitutes Lectin Pathway-Dependent C4 Activation
in serum from the MASP/- mice
In order to establish that the absence of MASP-2 was the direct cause of the loss of
lectin pathway-dependent C4 activation in the MASP/- mice, the effect of adding
recombinant MASP-2 protein to serum samples was examined in the C4 cleavage assay
described above. Functionally active murine MASP-2 and catalytically inactive murine
MASP-2A (in which the active-site serine residue in the serine protease domain was
substituted for the alanine residue) recombinant proteins were produced and purified as
described below in Example 3. Pooled serum from 4 MASP-2 -/- mice was pre-incubated
with increasing protein concentrations of recombinant murine MASP-2 or inactive
recombinant murine MASP-2A and C4 convertase activity was assayed as described above.
Results: As shown in FIGURE 6, the addition of functionally active murine
recombinant MASP-2 protein (shown as open triangles) to serum obtained from the MASP-2
-/- mice restored lectin pathway-dependent C4 activation in a protein concentration
dependent manner, whereas the catalytically inactive murine MASP-2A protein (shown as
stars) did not restore C4 activation. The results shown in FIGURE 6 are normalized to the
C4 activation observed with pooled wild-type mouse serum (shown as a dotted line).
EXAMPLE 3
This example describes the recombinant expression and protein production of
recombinant full-length human, rat and murine MASP-2, MASP-2 derived polypeptides, and
catalytically inactivated mutant forms of MASP-2
Expression of Full-length human, murine and rat MASP-2:
The full length cDNA sequence of human MASP-2 (SEQ ID NO: 4) was also
subcloned into the mammalian expression vector pCI-Neo (Promega), which drives
eukaryotic expression under the control of the CMV enhancer/promoter region (described in
Kaufman R.J. et al., Nucleic Acids Research 19:4485-90, 1991; Kaufman, Methods in
Enzymology, 185:537-66 (1991)). The full length mouse cDNA (SEQ ID NO:50) and rat
MASP-2 cDNA (SEQ ID NO:53) were each subcloned into the pED expression vector. The
MASP-2 expression vectors were then transfected into the adherent Chinese hamster ovary
cell line DXB1 using the standard calcium phosphate transfection procedure described in
Maniatis et al., 1989. Cells transfected with these constructs grew very slowly, implying that
the encoded protease is cytotoxic.
In another approach, the minigene construct (SEQ ID NO:49) containing the human
cDNA of MASP-2 driven by its endogenous promoter is transiently transfected into Chinese
hamster ovary cells (CHO). The human MASP-2 protein is secreted into the culture media
and isolated as described below.
Expression of Full-length catalytically inactive MASP-2:
Rationale: MASP-2 is activated by autocatalytic cleavage after the recognition
subcomponents MBL or ficolins (either L-ficolin, H-ficolin or M-ficolin) bind to their
respective carbohydrate pattern. Autocatalytic cleavage resulting in activation of MASP-2
often occurs during the isolation procedure of MASP-2 from serum, or during the
purification following recombinant expression. In order to obtain a more stable protein
preparation for use as an antigen, a catalytically inactive form of MASP-2, designed as
MASP-2A was created by replacing the serine residue that is present in the catalytic triad of
the protease domain with an alanine residue in rat (SEQ ID NO:55 Ser617 to Ala617); in
mouse (SEQ ID NO:52 Ser617 to Ala617); or in human (SEQ ID NO:3 Ser618 to Ala618).
In order to generate catalytically inactive human and murine MASP-2A proteins,
site-directed mutagenesis was carried out using the oligonucleotides shown in TABLE 5.
The oligonucleotides in TABLE 5 were designed to anneal to the region of the human and
murine cDNA encoding the enzymatically active serine and oligonucleotide contain a
mismatch in order to change the serine codon into an alanine codon. For example, PCR
oligonucleotides SEQ ID NOS:56-59 were used in combination with human MASP-2 cDNA
(SEQ ID NO:4) to amplify the region from the start codon to the enzymatically active serine
and from the serine to the stop codon to generate the complete open reading from of the
mutated MASP-2A containing the Ser618 to Ala618 mutation. The PCR products were
purified after agarose gel electrophoresis and band preparation and single adenosine overlaps
were generated using a standard tailing procedure. The adenosine tailed MASP-2A was then
cloned into the pGEM-T easy vector, transformed into E. coli.
A catalytically inactive rat MASP-2A protein was generated by kinasing and
annealing SEQ ID NO:64 and SEQ ID NO:65 by combining these two oligonucleotides in
equal molar amounts, heating at 100°C for 2 minutes and slowly cooling to room
temperature. The resulting annealed fragment has Pst1 and Xba1 compatible ends and was
inserted in place of the Pst1-Xba1 fragment of the wild-type rat MASP-2 cDNA (SEQ ID
NO:53) to generate rat MASP-2A.
'GAGGTGACGCAGGAGGGGCATTAGTGTTT 3' (SEQ ID NO:64)
' CTAGAAACACTAATGCCCCTCCTGCGTCACCTCTGCA 3' (SEQ ID NO:65)
The human, murine and rat MASP-2A were each further subcloned into either of the
mammalian expression vectors pED or pCI-Neo and transfected into the Chinese Hamster
ovary cell line DXB1 as described below.
In another approach, a catalytically inactive form of MASP-2 is constructed using the
method described in Chen et al., J. Biol. Chem., 276(28):25894-25902, 2001. Briefly, the
plasmid containing the full-length human MASP-2 cDNA (described in Thiel et al., Nature
386:506, 1997) is digested with Xho1 and EcoR1 and the MASP-2 cDNA (described herein
as SEQ ID NO:4) is cloned into the corresponding restriction sites of the pFastBac1
baculovirus transfer vector (Life Technologies, NY). The MASP-2 serine protease active
site at Ser618 is then altered to Ala618 by substituting the double-stranded oligonucleotides
encoding the peptide region amino acid 610-625 (SEQ ID NO:13) with the native region
amino acids 610 to 625 to create a MASP-2 full length polypeptide with an inactive protease
domain. Construction of Expression Plasmids Containing Polypeptide Regions Derived
from Human Masp-2.
The following constructs are produced using the MASP-2 signal peptide
(residues 1-15 of SEQ ID NO:5) to secrete various domains of MASP-2. A construct
expressing the human MASP-2 CUBI domain (SEQ ID NO:8) is made by PCR amplifying
the region encoding residues 1–121 of MASP-2 (SEQ ID NO:6) (corresponding to the
N-terminal CUB1 domain). A construct expressing the human MASP-2 CUBIEGF domain
(SEQ ID NO:9) is made by PCR amplifying the region encoding residues 1–166 of MASP-2
(SEQ ID NO:6) (corresponding to the N-terminal CUB1EGF domain). A construct
expressing the human MASP-2 CUBIEGFCUBII domain (SEQ ID NO:10) is made by PCR
amplifying the region encoding residues 1-293 of MASP-2 (SEQ ID NO:6) (corresponding
to the N-terminal CUBIEGFCUBII domain). The above mentioned domains are amplified
by PCR using VentR polymerase and pBS-MASP-2 as a template, according to established
PCR methods. The 5' primer sequence of the sense primer
(5'-CGGGATCCATGAGGCTGCTGACCCTC-3' SEQ ID NO:34) introduces a BamHI
restriction site (underlined) at the 5' end of the PCR products. Antisense primers for each of
the MASP-2 domains, shown below in TABLE 5, are designed to introduce a stop codon
(boldface) followed by an EcoRI site (underlined) at the end of each PCR product. Once
amplified, the DNA fragments are digested with BamHI and EcoRI and cloned into the
corresponding sites of the pFastBac1 vector. The resulting constructs are characterized by
restriction mapping and confirmed by dsDNA sequencing.
TABLE 5: MASP-2 PCR PRIMERS
MASP-2 domain 5' PCR Primer 3' PCR Primer
SEQ ID NO:8
CUBI (aa 1–121 of SEQ
ID NO:6)
'CGGGATCCATGA
GGCTGCTGACCCT
C-3' (SEQ ID NO:34)
'GGAATTCCTAGGCTGCAT
A (SEQ ID NO:35)
MASP-2 domain 5' PCR Primer 3' PCR Primer
SEQ ID NO:9
CUBIEGF (aa 1–166 of
SEQ ID NO:6)
'CGGGATCCATGA
GGCTGCTGACCCT
C-3' (SEQ ID NO:34)
'GGAATTCCTACAGGGCGC
T-3' (SEQ ID NO:36)
SEQ ID NO:10
CUBIEGFCUBII (aa
1-293 of SEQ ID NO:6)
'CGGGATCCATGA
GGCTGCTGACCCT
C-3' (SEQ ID NO:34)
'GGAATTCCTAGTAGTGGA
T 3' (SEQ ID NO:37)
SEQ ID NO:4
human MASP-2
'ATGAGGCTGCTG
ACCCTCCTGGGCC
TTC 3' (SEQ ID NO:
56)
hMASP-2_forward
'TTAAAATCACTAATTATG
TTCTCGATC 3' (SEQ ID NO:
59) hMASP-2_reverse
SEQ ID NO:4
human MASP-2 cDNA
'CAGAGGTGACGC
AGGAGGGGCAC 3'
(SEQ ID NO: 58)
hMASP-2_ala_forwar
d
'GTGCCCCTCCTGCGTCAC
CTCTG 3' (SEQ ID NO: 57)
hMASP-2_ala_reverse
SEQ ID NO:50
Murine MASP-2 cDNA
'ATGAGGCTACTC
ATCTTCCTGG3'
(SEQ ID NO: 60)
mMASP-2_forward
'TTAGAAATTACTTATTAT
GTTCTCAATCC3' (SEQ ID
NO: 63) mMASP-2_reverse
SEQ ID NO:50
Murine MASP-2 cDNA
'CCCCCCCTGCGT
CACCTCTGCAG3'
(SEQ ID NO: 62)
mMASP-2_ala_forwa
rd
'CTGCAGAGGTGACGCAG
GGGGGG 3' (SEQ ID NO: 61)
mMASP-2_ala_reverse
Recombinant eukaryotic expression of MASP-2 and protein production of
enzymatically inactive mouse, rat, and human MASP-2A.
The MASP-2 and MASP-2A expression constructs described above were transfected
into DXB1 cells using the standard calcium phosphate transfection procedure
(Maniatis et al., 1989). MASP-2A was produced in serum-free medium to ensure that
preparations were not contaminated with other serum proteins. Media was harvested from
confluent cells every second day (four times in total). The level of recombinant MASP-2A
averaged approximately 1.5 mg/liter of culture medium for each of the three species.
MASP-2A protein purification: The MASP-2A (Ser-Ala mutant described above)
was purified by affinity chromatography on MBP-A-agarose columns. This strategy enabled
rapid purification without the use of extraneous tags. MASP-2A (100-200 ml of medium
diluted with an equal volume of loading buffer (50 mM Tris-Cl, pH 7.5, containing 150 mM
NaCl and 25 mM CaCl2) was loaded onto an MBP-agarose affinity column (4 ml)
pre-equilibrated with 10 ml of loading buffer. Following washing with a further 10 ml of
loading buffer, protein was eluted in 1 ml fractions with 50 mM Tris-Cl, pH 7.5, containing
1.25 M NaCl and 10 mM EDTA. Fractions containing the MASP-2A were identified by
SDS-polyacrylamide gel electrophoresis. Where necessary, MASP-2A was purified further
by ion-exchange chromatography on a MonoQ column (HR 5/5). Protein was dialysed with
50 mM Tris-Cl pH 7.5, containing 50 mM NaCl and loaded onto the column equilibrated in
the same buffer. Following washing, bound MASP-2A was eluted with a 0.05–1 M NaCl
gradient over 10 ml.
Results: Yields of 0.25–0.5 mg of MASP-2A protein were obtained from 200 ml of
medium. The molecular mass of 77.5 kDa determined by MALDI-MS is greater than the
calculated value of the unmodified polypeptide (73.5 kDa) due to glycosylation. Attachment
of glycans at each of the N-glycosylation sites accounts for the observed mass. MASP-2A
migrates as a single band on SDS-polyacrylamide gels, demonstrating that it is not
proteolytically processed during biosynthesis. The weight-average molecular mass
determined by equilibrium ultracentrifugation is in agreement with the calculated value for
homodimers of the glycosylated polypeptide.
PRODUCTION OF RECOMBINANT HUMAN MASP-2 POLYPEPTIDES
Another method for producing recombinant MASP-2 and MASP2A derived
polypeptides is described in Thielens, N.M., et al., J. Immunol. 166:5068-5077, 2001.
Briefly, the Spodoptera frugiperda insect cells (Ready-Plaque Sf9 cells obtained from
Novagen, Madison, WI) are grown and maintained in Sf900II serum-free medium (Life
Technologies) supplemented with 50 IU/ml penicillin and 50 mg/ml streptomycin (Life
Technologies). The Trichoplusia ni (High Five) insect cells (provided by Jadwiga
Chroboczek, Institut de Biologie Structurale, Grenoble, France) are maintained in TC100
medium (Life Technologies) containing 10% FCS (Dominique Dutscher, Brumath, France)
supplemented with 50 IU/ml penicillin and 50 mg/ml streptomycin. Recombinant
baculoviruses are generated using the Bac-to-Bac system (Life Technologies). The bacmid
DNA is purified using the Qiagen midiprep purification system (Qiagen) and is used to
transfect Sf9 insect cells using cellfectin in Sf900 II SFM medium (Life Technologies) as
described in the manufacturer's protocol. Recombinant virus particles are collected 4 days
later, titrated by virus plaque assay, and amplified as described by King and Possee, in The
Baculovirus Expression System: A Laboratory Guide, Chapman and Hall Ltd., London,
pp. 111-114, 1992.
High Five cells (1.75 x 107
cells/175-cm2
tissue culture flask) are infected with the
recombinant viruses containing MASP-2 polypeptides at a multiplicity of infection of 2 in
Sf900 II SFM medium at 28°C for 96 h. The supernatants are collected by centrifugation
and diisopropyl phosphorofluoridate is added to a final concentration of 1 mM.
The MASP-2 polypeptides are secreted in the culture medium. The culture
supernatants are dialyzed against 50 mM NaCl, 1 mM CaCl2, 50 mM triethanolamine
hydrochloride, pH 8.1, and loaded at 1.5 ml/min onto a Q-Sepharose Fast Flow column
(Amersham Pharmacia Biotech) (2.8 x 12 cm) equilibrated in the same buffer. Elution is
conducted by applying a1.2 liter linear gradient to 350 mM NaCl in the same buffer.
Fractions containing the recombinant MASP-2 polypeptides are identified by Western blot
analysis, precipitated by addition of (NH4)2SO4 to 60% (w/v), and left overnight at 4°C. The
pellets are resuspended in 145 mM NaCl, 1 mM CaCl2, 50 mM triethanolamine
hydrochloride, pH 7.4, and applied onto a TSK G3000 SWG column (7.5 x 600 mm)
(Tosohaas, Montgomeryville, PA) equilibrated in the same buffer. The purified polypeptides
are then concentrated to 0.3 mg/ml by ultrafiltration on Microsep microconcentrators (m.w.
cut-off = 10,000) (Filtron, Karlstein, Germany).
EXAMPLE 4
This example describes a method of producing polyclonal antibodies against MASP-2
polypeptides.
Materials and Methods:
MASP-2 Antigens: Polyclonal anti-human MASP-2 antiserum is produced by
immunizing rabbits with the following isolated MASP-2 polypeptides: human MASP-2
(SEQ ID NO:6) isolated from serum; recombinant human MASP-2 (SEQ ID NO:6),
MASP-2A containing the inactive protease domain (SEQ ID NO:13), as described in
Example 3; and recombinant CUBI (SEQ ID NO:8), CUBEGFI (SEQ ID NO:9), and
CUBEGFCUBII (SEQ ID NO:10) expressed as described above in Example 3.
Polyclonal antibodies: Six-week old Rabbits, primed with BCG (bacillus
Calmette-Guerin vaccine) are immunized by injecting 100 μg of MASP-2 polypeptide at
100 μg/ml in sterile saline solution. Injections are done every 4 weeks, with antibody titer
monitored by ELISA assay as described in Example 5. Culture supernatants are collected
for antibody purification by protein A affinity chromatography.
EXAMPLE 5
This example describes a method for producing murine monoclonal antibodies
against rat or human MASP-2 polypeptides.
Materials and Methods:
Male A/J mice (Harlan, Houston, Tex.), 8-12 weeks old, are injected subcutaneously
with 100 μg human or rat rMASP-2 or rMASP-2A polypeptides (made as described in
Example 3) in complete Freund's adjuvant (Difco Laboratories, Detroit, Mich.) in 200 μl of
phosphate buffered saline (PBS) pH 7.4. At two-week intervals the mice are twice injected
subcutaneously with 50 μg of human or rat rMASP-2 or rMASP-2A polypeptide in
incomplete Freund's adjuvant. On the fourth week the mice are injected with 50 μg of
human or rat rMASP-2 or rMASP-2A polypeptide in PBS and are fused 4 days later.
For each fusion, single cell suspensions are prepared from the spleen of an
immunized mouse and used for fusion with Sp2/0 myeloma cells. 5x108 of the Sp2/0 and
5x108 spleen cells are fused in a medium containing 50% polyethylene glycol (M.W. 1450)
(Kodak, Rochester, N.Y.) and 5% dimethylsulfoxide (Sigma Chemical Co., St. Louis, Mo.).
The cells are then adjusted to a concentration of 1.5x105 spleen cells per 200 μl of the
suspension in Iscove medium (Gibco, Grand Island, N.Y.), supplemented with 10% fetal
bovine serum, 100 units/ml of penicillin, 100 μg/ml of streptomycin, 0.1 mM hypoxanthine,
0.4 μM aminopterin and 16 μM thymidine. Two hundred microliters of the cell suspension
are added to each well of about twenty 96-well microculture plates. After about ten days
culture supernatants are withdrawn for screening for reactivity with purified factor MASP-2
in an ELISA assay.
ELISA Assay: Wells of Immulon 2 (Dynatech Laboratories, Chantilly, Va.)
microtest plates are coated by adding 50 μl of purified hMASP-2 at 50 ng/ml or rat rMASP-2
(or rMASP-2A) overnight at room temperature. The low concentration of MASP-2 for
coating enables the selection of high-affinity antibodies. After the coating solution is
removed by flicking the plate, 200 μl of BLOTTO (non-fat dry milk) in PBS is added to each
well for one hour to block the non-specific sites. An hour later, the wells are then washed
with a buffer PBST (PBS containing 0.05% Tween 20). Fifty microliters of culture
supernatants from each fusion well is collected and mixed with 50 μl of BLOTTO and then
added to the individual wells of the microtest plates. After one hour of incubation, the wells
are washed with PBST. The bound murine antibodies are then detected by reaction with
horseradish peroxidase (HRP) conjugated goat anti-mouse IgG (Fc specific) (Jackson
ImmunoResearch Laboratories, West Grove, Pa.) and diluted at 1:2,000 in BLOTTO.
Peroxidase substrate solution containing 0.1% 3,3,5,5 tetramethyl benzidine (Sigma,
St. Louis, Mo.) and 0.0003% hydrogen peroxide (Sigma) is added to the wells for color
development for 30 minutes. The reaction is terminated by addition of 50 μl of 2M H2SO4
per well. The Optical Density at 450 nm of the reaction mixture is read with a BioTek
ELISA Reader (BioTek Instruments, Winooski, Vt.).
MASP-2 Binding Assay:
Culture supernatants that test positive in the MASP-2 ELISA assay described above
can be tested in a binding assay to determine the binding affinity the MASP-2 inhibitory
agents have for MASP-2. A similar assay can also be used to determine if the inhibitory
agents bind to other antigens in the complement system.
Polystyrene microtiter plate wells (96-well medium binding plates, Corning Costar,
Cambridge, MA) are coated with MASP-2 (20 ng/100 μl/well, Advanced Research
Technology, San Diego, CA) in phosphate-buffered saline (PBS) pH 7.4 overnight at 4ºC.
After aspirating the MASP-2 solution, wells are blocked with PBS containing 1% bovine
serum albumin (BSA; Sigma Chemical) for 2 h at room temperature. Wells without
MASP-2 coating serve as the background controls. Aliquots of hybridoma supernatants or
purified anti-MASP-2 MoAbs, at varying concentrations in blocking solution, are added to
the wells. Following a 2 h incubation at room temperature, the wells are extensively rinsed
with PBS. MASPbound anti-MASP-2 MoAb is detected by the addition of
peroxidase-conjugated goat anti-mouse IgG (Sigma Chemical) in blocking solution, which is
allowed to incubate for 1h at room temperature. The plate is rinsed again thoroughly with
PBS, and 100 μl of 3,3',5,5'-tetramethyl benzidine (TMB) substrate (Kirkegaard and Perry
Laboratories, Gaithersburg, MD) is added. The reaction of TMB is quenched by the addition
of 100 μl of 1M phosphoric acid, and the plate is read at 450 nm in a microplate reader
(SPECTRA MAX 250, Molecular Devices, Sunnyvale, CA).
The culture supernatants from the positive wells are then tested for the ability to
inhibit complement activation in a functional assay such as the C4 cleavage assay as
described in Example 2. The cells in positive wells are then cloned by limiting dilution.
The MoAbs are tested again for reactivity with hMASP-2 in an ELISA assay as described
above. The selected hybridomas are grown in spinner flasks and the spent culture
supernatant collected for antibody purification by protein A affinity chromatography.
EXAMPLE 6
This example describes the generation and production of humanized murine
anti-MASP-2 antibodies and antibody fragments.
A murine anti-MASP-2 monoclonal antibody is generated in Male A/J mice as
described in Example 5. The murine antibody is then humanized as described below to
reduce its immunogenicity by replacing the murine constant regions with their human
counterparts to generate a chimeric IgG and Fab fragment of the antibody, which is useful for
inhibiting the adverse effects of MASPdependent complement activation in human
subjects in accordance with the present invention.
1. Cloning of anti-MASP-2 variable region genes from murine hybridoma
cells. Total RNA is isolated from the hybridoma cells secreting anti-MASP-2 MoAb
(obtained as described in Example 7) using RNAzol following the manufacturer's protocol
(Biotech, Houston, Tex.). First strand cDNA is synthesized from the total RNA using oligo
dT as the primer. PCR is performed using the immunoglobulin constant C region-derived
3' primers and degenerate primer sets derived from the leader peptide or the first framework
region of murine VH or VK genes as the 5' primers. Anchored PCR is carried out as
described by Chen and Platsucas (Chen, P.F., Scand. J. Immunol. 35:539-549, 1992). For
cloning the VK gene, double-stranded cDNA is prepared using a Notl-MAK1 primer
(5'-TGCGGCCGCTGTAGGTGCTGTCTTT-3' SEQ ID NO:38). Annealed adaptors AD1
(5'-GGAATTCACTCGTTATTCTCGGA-3' SEQ ID NO:39) and AD2
(5'-TCCGAGAATAACGAGTG-3' SEQ ID NO:40) are ligated to both 5' and 3' termini of
the double-stranded cDNA. Adaptors at the 3' ends are removed by Notl digestion. The
digested product is then used as the template in PCR with the AD1 oligonucleotide as the 5'
primer and MAK2 (5'-CATTGAAAGCTTTGGGGTAGAAGTTGTTC-3' SEQ ID NO:41)
as the 3' primer. DNA fragments of approximately 500 bp are cloned into pUC19. Several
clones are selected for sequence analysis to verify that the cloned sequence encompasses the
expected murine immunoglobulin constant region. The Not1-MAK1 and MAK2
oligonucleotides are derived from the VK region and are 182 and 84 bp, respectively,
downstream from the first base pair of the C kappa gene. Clones are chosen that include the
complete VK and leader peptide.
For cloning the VH gene, double-stranded cDNA is prepared using the Not1 MAG1
primer (5'-CGCGGCCGCAGCTGCTCAGAGTGTAGA-3' SEQ ID NO:42). Annealed
adaptors AD1 and AD2 are ligated to both 5' and 3' termini of the double-stranded cDNA.
Adaptors at the 3' ends are removed by Notl digestion. The digested product are used as the
template in PCR with the AD1 oligonucleotide and MAG2
(5'-CGGTAAGCTTCACTGGCTCAGGGAAATA-3' SEQ ID NO:43) as primers. DNA
fragments of 500 to 600 bp in length are cloned into pUC19. The Notl-MAG1 and MAG2
oligonucleotides are derived from the murine C.7.1 region, and are 180 and 93 bp,
respectively, downstream from the first bp of the murine C.7.1 gene. Clones are chosen that
encompass the complete VH and leader peptide.
2. Construction of Expression Vectors for Chimeric MASP-2 IgG and Fab.
The cloned VH and VK genes described above are used as templates in a PCR reaction to
add the Kozak consensus sequence to the 5' end and the splice donor to the 3' end of the
nucleotide sequence. After the sequences are analyzed to confirm the absence of PCR errors,
the VH and VK genes are inserted into expression vector cassettes containing human C.1
and C. kappa respectively, to give pSV2neoVH-huC1 and pSV2neoV-huC. CsCl
gradient-purified plasmid DNAs of the heavy- and light-chain vectors are used to transfect
COS cells by electroporation. After 48 hours, the culture supernatant is tested by ELISA to
confirm the presence of approximately 200 ng/ml of chimeric IgG. The cells are harvested
and total RNA is prepared. First strand cDNA is synthesized from the total RNA using oligo
dT as the primer. This cDNA is used as the template in PCR to generate the Fd and kappa
DNA fragments. For the Fd gene, PCR is carried out using
'-AAGAAGCTTGCCGCCACCATGGATTGGCTGTGGAACT-3' (SEQ ID NO:44) as the
' primer and a CH1-derived 3' primer
(5'-CGGGATCCTCAAACTTTCTTGTCCACCTTGG-3' SEQ ID NO:45). The DNA
sequence is confirmed to contain the complete VH and the CH1 domain of human IgG1.
After digestion with the proper enzymes, the Fd DNA fragments are inserted at the HindIII
and BamHI restriction sites of the expression vector cassette pSV2dhfr-TUS to give
pSV2dhfrFd. The pSV2 plasmid is commercially available and consists of DNA segments
from various sources: pBR322 DNA (thin line) contains the pBR322 origin of DNA
replication (pBR ori) and the lactamase ampicillin resistance gene (Amp); SV40 DNA,
represented by wider hatching and marked, contains the SV40 origin of DNA replication
(SV40 ori), early promoter (5' to the dhfr and neo genes), and polyadenylation signal (3' to
the dhfr and neo genes). The SV40-derived polyadenylation signal (pA) is also placed at the
3' end of the Fd gene.
For the kappa gene, PCR is carried out using 5'-
AAGAAAGCTTGCCGCCACCATGTTCTCACTAGCTCT-3' (SEQ ID NO:46) as the 5'
primer and a CK-derived 3' primer (5'-CGGGATCCTTCTCCCTCTAACACTCT-3' SEQ ID
NO:47). DNA sequence is confirmed to contain the complete VK and human CK regions.
After digestion with proper restriction enzymes, the kappa DNA fragments are inserted at the
HindIII and BamHI restriction sites of the expression vector cassette pSV2neo-TUS to give
pSV2neoK. The expression of both Fd and .kappa genes are driven by the HCMV-derived
enhancer and promoter elements. Since the Fd gene does not include the cysteine amino acid
residue involved in the inter-chain disulfide bond, this recombinant chimeric Fab contains
non-covalently linked heavy- and light-chains. This chimeric Fab is designated as cFab.
To obtain recombinant Fab with an inter-heavy and light chain disulfide bond, the
above Fd gene may be extended to include the coding sequence for additional 9 amino acids
(EPKSCDKTH SEQ ID NO:48) from the hinge region of human IgG1. The BstEII-BamHI
DNA segment encoding 30 amino acids at the 3' end of the Fd gene may be replaced with
DNA segments encoding the extended Fd, resulting in pSV2dhfrFd/9aa.
3. Expression and Purification of Chimeric Anti-MASP-2 IgG
To generate cell lines secreting chimeric anti-MASP-2 IgG, NSO cells are transfected
with purified plasmid DNAs of pSV2neoVH-huC.1 and pSV2neoV-huC kappa by
electroporation. Transfected cells are selected in the presence of 0.7 mg/ml G418. Cells are
grown in a 250 ml spinner flask using serum-containing medium.
Culture supernatant of 100 ml spinner culture is loaded on a 10-ml PROSEP-A
column (Bioprocessing, Inc., Princeton, N.J.). The column is washed with 10 bed volumes
of PBS. The bound antibody is eluted with 50 mM citrate buffer, pH 3.0. Equal volume of
1 M Hepes, pH 8.0 is added to the fraction containing the purified antibody to adjust the pH
to 7.0. Residual salts are removed by buffer exchange with PBS by Millipore membrane
ultrafiltration (M.W. cut-off: 3,000). The protein concentration of the purified antibody is
determined by the BCA method (Pierce).
4. Expression and purification of chimeric anti-MASP-2 Fab
To generate cell lines secreting chimeric anti-MASP-2 Fab, CHO cells are transfected
with purified plasmid DNAs of pSV2dhfrFd (or pSV2dhfrFd/9aa) and pSV2neokappa, by
electroporation. Transfected cells are selected in the presence of G418 and methotrexate.
Selected cell lines are amplified in increasing concentrations of methotrexate. Cells are
single-cell subcloned by limiting dilution. High-producing single-cell subcloned cell lines
are then grown in 100 ml spinner culture using serum-free medium.
Chimeric anti-MASP-2 Fab is purified by affinity chromatography using a mouse
anti-idiotypic MoAb to the MASP-2 MoAb. An anti-idiotypic MASP-2 MoAb can be made
by immunizing mice with a murine anti-MASP-2 MoAb conjugated with keyhole limpet
hemocyanin (KLH) and screening for specific MoAb binding that can be competed with
human MASP-2. For purification, 100 ml of supernatant from spinner cultures of CHO cells
producing cFab or cFab/9aa are loaded onto the affinity column coupled with an
anti-idiotype MASP-2 MoAb. The column is then washed thoroughly with PBS before the
bound Fab is eluted with 50 mM diethylamine, pH 11.5. Residual salts are removed by
buffer exchange as described above. The protein concentration of the purified Fab is
determined by the BCA method (Pierce).
The ability of the chimeric MASP-2 IgG, cFab, and cFAb/9aa to inhibit
MASPdependent complement pathways may be determined by using the inhibitory assays
described in Example 2 or Example 7.
EXAMPLE 7
This example describes an in vitro C4 cleavage assay used as a functional screen to
identify MASP-2 inhibitory agents capable of blocking MASPdependent complement
activation via L-ficolin/P35, H-ficolin, M-ficolin or mannan.
C4 Cleavage Assay: A C4 cleavage assay has been described by Petersen,
S.V., et al., J. Immunol. Methods 257:107, 2001, which measures lectin pathway activation
resulting from lipoteichoic acid (LTA) from S. aureus which binds L-ficolin.
Reagents: Formalin-fixed S. aureous (DSM20233) is prepared as follows: bacteria
is grown overnight at 37ºC in tryptic soy blood medium, washed three times with PBS, then
fixed for 1 h at room temperature in PBS/0.5% formalin, and washed a further three times
with PBS, before being resuspended in coating buffer (15 mM Na2Co3, 35 mM NaHCO3,
pH 9.6).
Assay: The wells of a Nunc MaxiSorb microtiter plate (Nalgene Nunc International,
Rochester, NY) are coated with: 100 μl of formalin-fixed S. aureus DSM20233
(OD550 = 0.5) in coating buffer with 1 ug of L-ficolin in coating buffer. After overnight
incubation, wells are blocked with 0.1% human serum albumin (HSA) in TBS (10 mM
Tris-HCl, 140 mM NaCl, pH 7.4), then are washed with TBS containing 0.05% Tween 20
and 5 mM CaCl2 (wash buffer). Human serum samples are diluted in 20 mM Tris-HCl, 1 M
NaCl, 10 mM CaCl2, 0.05% Triton X-100, 0.1% HSA, pH 7.4, which prevents activation of
endogenous C4 and dissociates the C1 complex (composed of C1q, C1r and C1s). MASP-2
inhibitory agents, including anti-MASP-2 MoAbs and inhibitory peptides are added to the
serum samples in varying concentrations. The diluted samples are added to the plate and
incubated overnight at 4ºC. After 24 hours, the plates are washed thoroughly with wash
buffer, then 0.1 μg of purified human C4 (obtained as described in Dodds, A.W., Methods
Enzymol. 223:46, 1993) in 100 μl of 4 mM barbital, 145 mM NaCl, 2 mM CaCl2, 1 mM
MgCl2, pH 7.4 is added to each well. After 1.5 h at 37ºC, the plates are washed again and
C4b deposition is detected using alkaline phosphatase-conjugated chicken anti-human C4c
(obtained from Immunsystem, Uppsala, Sweden) and measured using the colorimetric
substrate ρ-nitrophenyl phosphate.
C4 Assay on mannan: The assay described above is adapted to measure lectin
pathway activation via MBL by coating the plate with LSP and mannan prior to adding
serum mixed with various MASP-2 inhibitory agents.
C4 assay on H-ficolin (Hakata Ag): The assay described above is adapted to
measure lectin pathway activation via H-ficolin by coating the plate with LPS and H-ficolin
prior to adding serum mixed with various MASP-2 inhibitory agents.
EXAMPLE 8
The following assay demonstrates the presence of classical pathway activation in
wild-type and MASP/- mice.
Methods: Immune complexes were generated in situ by coating microtiter plates
(Maxisorb, Nunc, cat. No. 442404, Fisher Scientific) with 0.1% human serum albumin in
mM Tris, 140 mM NaCl, pH 7.4 for 1 hours at room temperature followed by overnight
incubation at 4°C with sheep anti whole serum antiserum (Scottish Antibody Production
Unit, Carluke, Scotland) diluted 1:1000 in TBS/tween/Ca2+. Serum samples were obtained
from wild-type and MASP/- mice and added to the coated plates. Control samples were
prepared in which C1q was depleted from wild-type and MASP/- serum samples.
C1q-depleted mouse serum was prepared using protein-A-coupled Dynabeads (Dynal
Biotech, Oslo, Norway) coated with rabbit anti-human C1q IgG (Dako, Glostrup, Denmark),
according to the supplier's instructions. The plates were incubated for 90 minutes at 37°C.
Bound C3b was detected with a polyclonal anti-human-C3c Antibody (Dako A 062) diluted
in TBS/tw/ Ca++ at 1:1000. The secondary antibody is goat anti-rabbit IgG.
Results: FIGURE 7 shows the relative C3b deposition levels on plates coated with
IgG in wild-type serum, MASP/- serum, C1q-depleted wild-type and C1q-depleted
MASP/- serum. These results demonstrate that the classical pathway is intact in the
MASP/- mouse strain.
EXAMPLE 9
The following assay is used to test whether a MASP-2 inhibitory agent blocks the
classical pathway by analyzing the effect of a MASP-2 inhibitory agent under conditions in
which the classical pathway is initiated by immune complexes.
Methods: To test the effect of a MASP-2 inhibitory agent on conditions of
complement activation where the classical pathway is initiated by immune complexes,
triplicate 50 μl samples containing 90% NHS are incubated at 37ºC in the presence of
μg/ml immune complex (IC) or PBS, and parallel triplicate samples (+/-IC) are also
included which contain 200 nM anti-properdin monoclonal antibody during the 37ºC
incubation. After a two hour incubation at 37ºC, 13 mM EDTA is added to all samples to
stop further complement activation and the samples are immediately cooled to 5ºC. The
samples are then stored at -70ºC prior to being assayed for complement activation products
(C3a and sC5b-9) using ELISA kits (Quidel, Catalog Nos. A015 and A009) following the
manufacturer's instructions.
EXAMPLE 10
This example describes the identification of high affinity anti-MASP-2 Fab2 antibody
fragments that block MASP-2 activity.
Background and rationale: MASP-2 is a complex protein with many separate
functional domains, including: binding site(s) for MBL and ficolins, a serine protease
catalytic site, a binding site for proteolytic substrate C2, a binding site for proteolytic
substrate C4, a MASP-2 cleavage site for autoactivation of MASP-2 zymogen, and two Ca++
binding sites. Fab2 antibody fragments were identified that bind with high affinity to
MASP-2, and the identified Fab2 fragments were tested in a functional assay to determine if
they were able to block MASP-2 functional activity.
To block MASP-2 functional activity, an antibody or Fab2 antibody fragment must
bind and interfere with a structural epitope on MASP-2 that is required for MASP-2
functional activity. Therefore, many or all of the high affinity binding anti-MASP-2 Fab2s
may not inhibit MASP-2 functional activity unless they bind to structural epitopes on
MASP-2 that are directly involved in MASP-2 functional activity.
A functional assay that measures inhibition of lectin pathway C3 convertase
formation was used to evaluate the "blocking activity" of anti-MASP-2 Fab2s. It is known
that the primary physiological role of MASP-2 in the lectin pathway is to generate the next
functional component of the lectin-mediated complement pathway, namely the lectin
pathway C3 convertase. The lectin pathway C3 convertase is a critical enzymatic complex
(C4bC2a) that proteolytically cleaves C3 into C3a and C3b. MASP-2 is not a structural
component of the lectin pathway C3 convertase (C4bC2a); however, MASP-2 functional
activity is required in order to generate the two protein components (C4b, C2a) that comprise
the lectin pathway C3 convertase. Furthermore, all of the separate functional activities of
MASP-2 listed above appear to be required in order for MASP-2 to generate the lectin
pathway C3 convertase. For these reasons, a preferred assay to use in evaluating the
"blocking activity" of anti-MASP-2 Fab2s is believed to be a functional assay that measures
inhibition of lectin pathway C3 convertase formation.
Generation of High Affinity Fab2s: A phage display library of human variable
light and heavy chain antibody sequences and automated antibody selection technology for
identifying Fab2s that react with selected ligands of interest was used to create high affinity
Fab2s to rat MASP-2 protein (SEQ ID NO:55). A known amount of rat MASP-2 (~1 mg,
>85% pure) protein was utilized for antibody screening. Three rounds of amplification were
utilized for selection of the antibodies with the best affinity. Approximately 250 different
hits expressing antibody fragments were picked for ELISA screening. High affinity hits
were subsequently sequenced to determine uniqueness of the different antibodies.
Fifty unique anti-MASP-2 antibodies were purified and 250 µg of each purified Fab2
antibody was used for characterization of MASP-2 binding affinity and complement pathway
functional testing, as described in more detail below.
Assays used to Evaluate the Inhibitory (blocking) Activity of Anti-MASP-2
Fab2s
1. Assay to Measure Inhibition of Formation of Lectin Pathway C3
Convertase:
Background: The lectin pathway C3 convertase is the enzymatic complex (C4bC2a)
that proteolytically cleaves C3 into the two potent proinflammatory fragments, anaphylatoxin
C3a and opsonic C3b. Formation of C3 convertase appears to a key step in the lectin
pathway in terms of mediating inflammation. MASP-2 is not a structural component of the
lectin pathway C3 convertase (C4bC2a); therefore anti-MASP-2 antibodies (or Fab2) will
not directly inhibit activity of preexisting C3 convertase. However, MASP-2 serine protease
activity is required in order to generate the two protein components (C4b, C2a) that comprise
the lectin pathway C3 convertase. Therefore, anti-MASP-2 Fab2 which inhibit MASP-2
functional activity (i.e., blocking anti-MASP-2 Fab2) will inhibit de novo formation of lectin
pathway C3 convertase. C3 contains an unusual and highly reactive thioester group as part
of its structure. Upon cleavage of C3 by C3 convertase in this assay, the thioester group on
C3b can form a covalent bond with hydroxyl or amino groups on macromolecules
immobilized on the bottom of the plastic wells via ester or amide linkages, thus facilitating
detection of C3b in the ELISA assay.
Yeast mannan is a known activator of the lectin pathway. In the following method to
measure formation of C3 convertase, plastic wells coated with mannan were incubated for
min at 37ºC with diluted rat serum to activate the lectin pathway. The wells were then
washed and assayed for C3b immobilized onto the wells using standard ELISA methods.
The amount of C3b generated in this assay is a direct reflection of the de novo formation of
lectin pathway C3 convertase. Anti-MASP-2 Fab2s at selected concentrations were tested in
this assay for their ability to inhibit C3 convertase formation and consequent C3b generation.
Methods:
96-well Costar Medium Binding plates were incubated overnight at 5ºC with mannan
diluted in 50 mM carbonate buffer, pH 9.5 at 1 ug/50 l/well. After overnight incubation,
each well was washed three times with 200 l PBS. The wells were then blocked with 100
l/well of 1% bovine serum albumin in PBS and incubated for one hour at room temperature
with gentle mixing. Each well was then washed three times with 200 l of PBS. The
anti-MASP-2 Fab2 samples were diluted to selected concentrations in Ca++ and Mg++
containing GVB buffer (4.0 mM barbital, 141 mM NaCl, 1.0 mM MgCl2, 2.0 mM CaCl2,
0.1% gelatin, pH 7.4) at 5 C. A 0.5% rat serum was added to the above samples at 5 C and
100 l was transferred to each well. Plates were covered and incubated for 30 minutes in a
37 C waterbath to allow complement activation. The reaction was stopped by transferring
the plates from the 37 C waterbath to a container containing an ice-water mix. Each well
was washed five times with 200 l with PBS-Tween 20 (0.05% Tween 20 in PBS), then
washed two times with 200 l PBS. A 100 l/well of 1:10,000 dilution of the primary
antibody (rabbit anti-human C3c, DAKO A0062) was added in PBS containing 2.0 mg/ml
bovine serum albumin and incubated 1 hr at room temperature with gentle mixing. Each
well was washed 5 x 200 l PBS. 100 l/well of 1:10,000 dilution of the secondary antibody
(peroxidase-conjugated goat anti-rabbit IgG, American Qualex A102PU) was added in PBS
containing 2.0 mg/ml bovine serum albumin and incubated for one hour at room temperature
on a shaker with gentle mixing. Each well was washed five times with 200 l with PBS.
100 l/well of the peroxidase substrate TMB (Kirkegaard & Perry Laboratories) was added
and incubated at room temperature for 10 min. The peroxidase reaction was stopped by
adding 100 l/well of 1.0 M H3PO4 and the OD450. was measured.
2. Assay to Measure Inhibition of MASPdependent C4 Cleavage
Background: The serine protease activity of MASP-2 is highly specific and only two
protein substrates for MASP-2 have been identified; C2 and C4. Cleavage of C4 generates
C4a and C4b. Anti-MASP-2 Fab2 may bind to structural epitopes on MASP-2 that are
directly involved in C4 cleavage (e.g., MASP-2 binding site for C4; MASP-2 serine protease
catalytic site) and thereby inhibit the C4 cleavage functional activity of MASP-2.
Yeast mannan is a known activator of the lectin pathway. In the following method to
measure the C4 cleavage activity of MASP-2, plastic wells coated with mannan were
incubated for 30 minutes at 37 C with diluted rat serum to activate the lectin pathway. Since
the primary antibody used in this ELISA assay only recognizes human C4, the diluted rat
serum was also supplemented with human C4 (1.0 g/ml). The wells were then washed and
assayed for human C4b immobilized onto the wells using standard ELISA methods. The
amount of C4b generated in this assay is a measure of MASP-2 dependent C4 cleavage
activity. Anti-MASP-2 Fab2 at selected concentrations were tested in this assay for their
ability to inhibit C4 cleavage.
Methods: 96-well Costar Medium Binding plates were incubated overnight at 5 C
with mannan diluted in 50 mM carbonate buffer, pH 9.5 at 1.0 g/50 l/well. Each well was
washed 3X with 200 l PBS. The wells were then blocked with 100 l/well of 1% bovine
serum albumin in PBS and incubated for one hour at room temperature with gentle mixing.
Each well was washed 3X with 200 l of PBS. Anti-MASP-2 Fab2 samples were diluted to
selected concentrations in Ca++ and Mg++ containing GVB buffer (4.0 mM barbital, 141 mM
NaCl, 1.0 mM MgCl2, 2.0 mM CaCl2, 0.1% gelatin, pH 7.4) at 5 C. 1.0 g/ml human C4
(Quidel) was also included in these samples. 0.5% rat serum was added to the above samples
at 5 C and 100 l was transferred to each well. The plates were covered and incubated for
30 min in a 37 C waterbath to allow complement activation. The reaction was stopped by
transferring the plates from the 37 C waterbath to a container containing an ice-water mix.
Each well was washed 5 x 200 l with PBS-Tween 20 (0.05% Tween 20 in PBS), then each
well was washed with 2X with 200 l PBS. 100 l/well of 1:700 dilution of
biotin-conjugated chicken anti-human C4c (Immunsystem AB, Uppsala, Sweden) was added
in PBS containing 2.0 mg/ml bovine serum albumin (BSA) and incubated one hour at room
temperature with gentle mixing. Each well was washed 5 x 200 l PBS. 100 l/well of 0.1
g/ml of peroxidase-conjugated streptavidin (Pierce Chemical #21126) was added in PBS
containing 2.0 mg/ml BSA and incubated for one hour at room temperature on a shaker with
gentle mixing. Each well was washed 5 x 200 l with PBS. 100 l/well of the peroxidase
substrate TMB (Kirkegaard & Perry Laboratories) was added and incubated at room
temperature for 16 min. The peroxidase reaction was stopped by adding 100 l/well of 1.0
M H3PO4 and the OD450 .was measured.
3. Binding Assay of anti-rat MASP-2 Fab2 to 'Native' rat MASP-2
Background: MASP-2 is usually present in plasma as a MASP-2 dimer complex that
also includes specific lectin molecules (mannose-binding protein (MBL) and ficolins).
Therefore, if one is interested in studying the binding of anti-MASP-2 Fab2 to the
physiologically relevant form of MASP-2, it is important to develop a binding assay in which
the interaction between the Fab2 and 'native' MASP-2 in plasma is used, rather than purified
recombinant MASP-2. In this binding assay the 'native' MASPMBL complex from 10%
rat serum was first immobilized onto mannan-coated wells. The binding affinity of various
anti-MASP-2 Fab2s to the immobilized 'native' MASP-2 was then studied using a standard
ELISA methodology.
Methods: 96-well Costar High Binding plates were incubated overnight at 5ºC with
mannan diluted in 50 mM carbonate buffer, pH 9.5 at 1 g/50 l/well. Each well was
washed 3X with 200 l PBS. The wells were blocked with 100 l/well of 0.5% nonfat dry
milk in PBST (PBS with 0.05% Tween 20) and incubated for one hour at room temperature
with gentle mixing. Each well was washed 3X with 200 l of TBS/Tween/Ca++ Wash Buffer
(Tris-buffered saline, 0.05% Tween 20, containing 5.0 mM CaCl2, pH 7.4. 10% rat serum in
High Salt Binding Buffer (20 mM Tris, 1.0 M NaCl, 10 mM CaCl2, 0.05% Triton-X100,
0.1% (w/v) bovine serum albumin, pH 7.4) was prepared on ice. 100 l/well was added and
incubated overnight at 5ºC. Wells were washed 3X with 200 l of TBS/Tween/Ca++ Wash
Buffer. Wells were then washed 2X with 200 l PBS. 100 l/well of selected concentration
of anti-MASP-2 Fab2 diluted in Ca++ and Mg++ containing GVB Buffer (4.0 mM barbital,
141 mM NaCl, 1.0 mM MgCl2, 2.0 mM CaCl2, 0.1% gelatin, pH 7.4) was added and
incubated for one hour at room temperature with gentle mixing. Each well was washed
x 200 l PBS. 100 l/well of HRP-conjugated goat anti-Fab2 (Biogenesis Cat No
0500-0099) diluted 1:5000 in 2.0 mg/ml bovine serum albumin in PBS was added and
incubated for one hour at room temperature with gentle mixing. Each well was washed
x 200 l PBS. 100 l/well of the peroxidase substrate TMB (Kirkegaard & Perry
Laboratories) was added and incubated at room temperature for 70 min. The peroxidase
reaction was stopped by adding 100 l/well of 1.0 M H3PO4 and OD450. was measured.
RESULTS:
Approximately 250 different Fab2s that reacted with high affinity to the rat MASP-2
protein were picked for ELISA screening. These high affinity Fab2s were sequenced to
determine the uniqueness of the different antibodies, and 50 unique anti-MASP-2 antibodies
were purified for further analysis. 250 ug of each purified Fab2 antibody was used for
characterization of MASP-2 binding affinity and complement pathway functional testing.
The results of this analysis is shown below in TABLE 6.
TABLE 6: ANTI-MASP-2 FAB2 THAT BLOCK LECTIN PATHWAY COMPLEMENT
ACTIVATION
Fab2 antibody # C3 Convertase
(IC50 (nM)
Kd C4 Cleavage
IC50 (nM)
88 0.32 4.1 ND
41 0.35 0.30 0.81
11 0.46 0.86 <2 nM
86 0.53 1.4 ND
81 0.54 2.0 ND
66 0.92 4.5 ND
57 0.95 3.6 <2 nM
40 1.1 7.2 0.68
58 1.3 2.6 ND
60 1.6 3.1 ND
52 1.6 5.8 <2 nM
63 2.0 6.6 ND
49 2.8 8.5 <2 nM
89 3.0 2.5 ND
71 3.0 10.5 ND
87 6.0 2.5 ND
67 10.0 7.7 ND
As shown above in TABLE 6, of the 50 anti-MASP-2 Fab2s tested, seventeen Fab2s
were identified as MASP-2 blocking Fab2 that potently inhibit C3 convertase formation with
IC50 equal to or less than 10 nM Fab2s (a 34% positive hit rate). Eight of the seventeen
Fab2s identified have IC50s in the subnanomolar range. Furthermore, all seventeen of the
MASP-2 blocking Fab2s shown in TABLE 6 gave essentially complete inhibition of C3
convertase formation in the lectin pathway C3 convertase assay. FIGURE 8A graphically
illustrates the results of the C3 convertase formation assay for Fab2 antibody #11, which is
representative of the other Fab2 antibodies tested, the results of which are shown in
TABLE 6. This is an important consideration, since it is theoretically possible that a
"blocking" Fab2 may only fractionally inhibit MASP-2 function even when each MASP-2
molecule is bound by the Fab2.
Although mannan is a known activator of the lectin pathway, it is theoretically
possible that the presence of anti-mannan antibodies in the rat serum might also activate the
classical pathway and generate C3b via the classical pathway C3 convertase. However, each
of the seventeen blocking anti-MASP-2 Fab2s listed in this example potently inhibits C3b
generation (>95 %), thus demonstrating the specificity of this assay for lectin pathway C3
convertase.
Binding assays were also performed with all seventeen of the blocking Fab2s in order
to calculate an apparent Kd for each. The results of the binding assays of anti-rat MASP-2
Fab2s to native rat MASP-2 for six of the blocking Fab2s are also shown in TABLE 6.
FIGURE 8B graphically illustrates the results of a binding assay with the Fab2 antibody
#11. Similar binding assays were also carried out for the other Fab2s, the results of which
are shown in TABLE 6. In general, the apparent Kds obtained for binding of each of the six
Fab2s to 'native' MASP-2 corresponds reasonably well with the IC50 for the Fab2 in the C3
convertase functional assay. There is evidence that MASP-2 undergoes a conformational
change from an 'inactive' to an 'active' form upon activation of its protease activity
(Feinberg et al., EMBO J 22:2348-59 (2003); Gal et al., J. Biol. Chem. 280:33435-44
(2005)). In the normal rat plasma used in the C3 convertase formation assay, MASP-2 is
present primarily in the 'inactive' zymogen conformation. In contrast, in the binding assay,
MASP-2 is present as part of a complex with MBL bound to immobilized mannan; therefore,
the MASP-2 would be in the 'active' conformation (Petersen et al., J. Immunol Methods
257:107-16, 2001). Consequently, one would not necessarily expect an exact
correspondence between the IC50 and Kd for each of the seventeen blocking Fab2 tested in
these two functional assays since in each assay the Fab2 would be binding a different
conformational form of MASP-2. Never-the-less, with the exception of Fab2 #88, there
appears to be a reasonably close correspondence between the IC50 and apparent Kd for each
of the other sixteen Fab2 tested in the two assays (see TABLE 6).
Several of the blocking Fab2s were evaluated for inhibition of MASP-2 mediated
cleavage of C4. FIGURE 8C graphically illustrates the results of a C4 cleavage assay,
showing inhibition with Fab2 #41, with an IC50=0.81 nM (see TABLE 6). As shown in
FIGURE 9, all of the Fab2s tested were found to inhibit C4 cleavage with IC50s similar to
those obtained in the C3 convertase assay (see TABLE 6).
Although mannan is a known activator of the lectin pathway, it is theoretically
possible that the presence of anti-mannan antibodies in the rat serum might also activate the
classical pathway and thereby generate C4b by C1s-mediated cleavage of C4. However,
several anti-MASP-2 Fab2s have been identified which potently inhibit C4b generation (>95
%), thus demonstrating the specificity of this assay for MASP-2 mediated C4 cleavage. C4,
like C3, contains an unusual and highly reactive thioester group as part of its structure. Upon
cleavage of C4 by MASP-2 in this assay, the thioester group on C4b can form a covalent
bond with hydroxyl or amino groups on macromolecules immobilized on the bottom of the
plastic wells via ester or amide linkages, thus facilitating detection of C4b in the ELISA
assay.
These studies clearly demonstrate the creation of high affinity FAB2s to rat MASP-2
protein that functionally block both C4 and C3 convertase activity, thereby preventing lectin
pathway activation.
EXAMPLE 11
This Example describes the epitope mapping for several of the blocking anti-rat
MASP-2 Fab2 antibodies that were generated as described in Example 10.
Methods:
As shown in FIGURE 10, the following proteins, all with N-terminal 6X His tags
were expressed in CHO cells using the pED4 vector:
rat MASP-2A, a full length MASP-2 protein, inactivated by altering the serine at the
active center to alanine (S613A);
rat MASP-2K, a full-length MASP-2 protein altered to reduce autoactivation
(R424K);
CUBI-II, an N-terminal fragment of rat MASP-2 that contains the CUBI, EGF-like
and CUBII domains only; and
CUBI/EGF-like, an N-terminal fragment of rat MASP-2 that contains the CUBI and
EGF-like domains only.
These proteins were purified from culture supernatants by nickel-affinity
chromatography, as previously described (Chen et al., J. Biol. Chem. 276:25894-02 (2001)).
A C-terminal polypeptide (CCPII-SP), containing CCPII and the serine protease
domain of rat MASP-2, was expressed in E. coli as a thioredoxin fusion protein using
pTrxFus (Invitrogen). Protein was purified from cell lysates using Thiobond affinity resin.
The thioredoxin fusion partner was expressed from empty pTrxFus as a negative control.
All recombinant proteins were dialyzed into TBS buffer and their concentrations
determined by measuring the OD at 280 nm.
DOT BLOT ANALYSIS:
Serial dilutions of the five recombinant MASP-2 polypeptides described above and
shown in FIGURE 10 (and the thioredoxin polypeptide as a negative control for
CCPII-serine protease polypeptide) were spotted onto a nitrocellulose membrane. The
amount of protein spotted ranged from 100 ng to 6.4 pg, in five-fold steps. In later
experiments, the amount of protein spotted ranged from 50 ng down to 16 pg, again in
five-fold steps. Membranes were blocked with 5% skimmed milk powder in TBS (blocking
buffer) then incubated with 1.0 μg/ml anti-MASP-2 Fab2s in blocking buffer (containing
.0 mM Ca2+). Bound Fab2s were detected using HRP-conjugated anti-human Fab
(AbD/Serotec; diluted 1/10,000) and an ECL detection kit (Amersham). One membrane was
incubated with polyclonal rabbit-anti human MASP-2 Ab (described in Stover et al., J
Immunol 163:6848-59 (1999)) as a positive control. In this case, bound Ab was detected
using HRP-conjugated goat anti-rabbit IgG (Dako; diluted 1/2,000).
MASP-2 Binding Assay
ELISA plates were coated with 1.0 μg/well of recombinant MASP-2A or CUBI-II
polypeptide in carbonate buffer (pH 9.0) overnight at 4ºC. Wells were blocked with 1%
BSA in TBS, then serial dilutions of the anti-MASP-2 Fab2s were added in TBS containing
.0 mM Ca2+. The plates were incubated for one hour at RT. After washing three times with
TBS/tween/Ca2+, HRP-conjugated anti-human Fab (AbD/Serotec) diluted 1/10,000 in TBS/
Ca2+ was added and the plates incubated for a further one hour at RT. Bound antibody was
detected using a TMB peroxidase substrate kit (Biorad).
RESULTS:
Results of the dot blot analysis demonstrating the reactivity of the Fab2s with various
MASP-2 polypeptides are provided below in TABLE 7. The numerical values provided in
TABLE 7 indicate the amount of spotted protein required to give approximately
half-maximal signal strength. As shown, all of the polypeptides (with the exception of the
thioredoxin fusion partner alone) were recognized by the positive control Ab (polyclonal
anti-human MASP-2 sera, raised in rabbits).
TABLE 7: REACTIVITY WITH VARIOUS RECOMBINANT RAT MASP-2
POLYPEPTIDES ON DOT BLOTS
Fab2
Antibody #
MASP-2A CUBI-II CUBI/EGF-like CCPII-SP Thioredoxin
40 0.16 ng NR NR 0.8 ng NR
41 0.16 ng NR NR 0.8 ng NR
11 0.16 ng NR NR 0.8 ng NR
49 0.16 ng NR NR >20 ng NR
52 0.16 ng NR NR 0.8 ng NR
57 0.032 ng NR NR NR NR
58 0.4 ng NR NR 2.0 ng NR
60 0.4 ng 0.4 ng NR NR NR
63 0.4 ng NR NR 2.0 ng NR
66 0.4 ng NR NR 2.0 ng NR
67 0.4 ng NR NR 2.0 ng NR
71 0.4 ng NR NR 2.0 ng NR
81 0.4 ng NR NR 2.0 ng NR
86 0.4 ng NR NR 10 ng NR
87 0.4 ng NR NR 2.0 ng NR
Fab2
Antibody #
MASP-2A CUBI-II CUBI/EGF-like CCPII-SP Thioredoxin
Positive
Control
<0.032 ng 0.16 ng 0.16 ng <0.032 ng NR
pathway activity was observed over the second and third weeks, with complete lectin
pathway restoration in the mice by 17 days post anti-MASP-2 MoAb administration.
NR = No reaction. The positive control antibody is polyclonal anti-human MASP-2 sera,
raised in rabbits.
All of the Fab2s reacted with MASP-2A as well as MASP-2K (data not shown). The
majority of the Fab2s recognized the CCPII-SP polypeptide but not the N-terminal
fragments. The two exceptions are Fab2 #60 and Fab2 #57. Fab2 #60 recognizes MASP-2A
and the CUBI-II fragment, but not the CUBI/EGF-like polypeptide or the CCPII-SP
polypeptide, suggesting it binds to an epitope in CUBII, or spanning the CUBII and the
EGF-like domain. Fab2 # 57 recognizes MASP-2A but not any of the MASP-2 fragments
tested, indicating that this Fab2 recognizes an epitope in CCP1. Fab2 #40 and #49 bound
only to complete MASP-2A. In the ELISA binding assay shown in FIGURE 11, Fab2 #60
also bound to the CUBI-II polypeptide, albeit with a slightly lower apparent affinity.
These finding demonstrate the identification of unique blocking Fab2s to multiple
regions of the MASP-2 protein
EXAMPLE 12
This Example describes the analysis of MASP/- mice in a Murine Renal
Ischemia/Reperfusion Model.
Background/Rationale: Ischemia-Reperfusion (I/R) injury in kidney at body
temperature has relevance in a number of clinical conditions, including hypovolaemic shock,
renal artery occlusion and cross-clamping procedures.
Kidney ischemia-reperfusion (I/R) is an important cause of acute renal failure,
associated with a mortality rate of up to 50% (Levy et al., JAMA 275:1489-94, 1996;
Thadhani et al., N. Engl. J. Med. 334:1448-60, 1996). Post-transplant renal failure is a
common and threatening complication after renal transplantation (Nicholson et al., Kidney
Int. 58:2585-91, 2000). Effective treatment for renal I/R injury is currently not available and
hemodialysis is the only treatment available. The pathophysiology of renal I/R injury is
complicated. Recent studies have shown that the lectin pathway of complement activation
may have an important role in the pathogenesis of renal I/R injury (deVries et al., Am. J.
Path. 165:1677-88, 2004).
Methods:
A MASP-2(-/-) mouse was generated as described in Example 1 and backcrossed for
at least 10 generations with C57Bl/6. Six male MASP-2(-/-) and six wildtype (+/+) mice
weighing between 22-25 g were administered an intraperitoneal injection of Hypnovel
(6.64 mg/kg; Roche products Ltd. Welwyn Garden City, UK), and subsequently
anaesthetized by inhalation of isoflurane (Abbott Laboratories Ltd., Kent, UK). Isoflurane
was chosen because it is a mild inhalation anaesthetic with minimal liver toxicity; the
concentrations are produced accurately and the animal recovers rapidly, even after prolonged
anaesthesia. Hypnovel was administered because it produces a condition of
neuroleptanalgesia in the animal and means that less isoflurane needs to be administered. A
warm pad was placed beneath the animal in order to maintain a constant body temperature.
Next, a midline abdominal incision was performed and the body cavity held open using a
pair of retractors. Connective tissue was cleared above and below the renal vein and artery
of both right and left kidneys, and the renal pedicle was clamped via the application of
microaneurysm clamps for a period of 55 minutes. This period of ischemia was based
initially on a previous study performed in this laboratory (Zhou et al., J. Clin. Invest.
105:1363-71 (2000)). In addition, a standard ischemic time of 55 minutes was chosen
following ischemic titration and it was found that 55 minutes gave consistent injury that was
also reversible, with low mortality, less than 5%. After occlusion, 0.4 ml of warm saline
(37C) was placed in the abdominal cavity and then the abdomen was closed for the period
of ischemia. Following removal of the microaneurysm clamps, the kidneys were observed
until color change, an indication of blood re-flow to the kidneys. A further 0.4 ml of warm
saline was placed in the abdominal cavity and the opening was sutured, whereupon animals
were returned to their cages. Tail blood samples were taken at 24 hours after removing the
clamps, and at 48 hours the mice were sacrificed and an additional blood sample was
collected.
Assessment of Renal Injury: Renal function was assessed at 24 and 48 hours after
reperfusion in six male MASP-2(-/-) and six WT (+/+) mice. Blood creatinine measurement
was determined by mass spectrometry, which provides a reproducible index of renal function
(sensitivity < 1.0 µmol/L). FIGURE 12 graphically illustrates the blood urea nitrogen
clearance for wildtype C57Bl/6 controls and MASP-2 (-/-) at 24 hours and 48 hours after
reperfusion. As shown in FIGURE 12, MASP-2(-/-) mice displayed a significant reduction
in the amount of blood urea at 24 and 48 hours, in comparison to wildtype control mice,
indicating a protective functional effect from renal damage in the ischemia reperfusion injury
model.
Overall, increased blood urea was seen in both the WT (+/+) and MASP-2 (-/-) mice
at 24 and 48 hours following the surgical procedure and ischemic insult. Levels of blood
urea in a non-ischemic WT (+/+) surgery animal was separately determined to be
.8 mmol/L. In addition to the data presented in FIGURE 12, one MASP-2 (-/-) animal
showed nearly complete protection from the ischemic insult, with values of 6.8 and
9.6 mmol/L at 24 and 48 hours, respectively. This animal was excluded from the group
analysis as a potential outlier, wherein no ischemic injury may have been present. Therefore,
the final analysis shown in FIGURE 12 included 5 MASP-2(-/-) mice and 6 WT (+/+) mice
and a statistically significant reduction in blood urea was seen at 24 and 48 hours in the
MASP-2 (-/-) mice (Student t-test p<0.05). These findings indicate inhibition of MASP-2
activity would be expected to have a protective or therapeutic effect from renal damage due
to ischemic injury.
EXAMPLE 13
This Example describes the results of MASP/- in a Murine Macular Degeneration
Model.
Background/Rationale: Age-related macular degeneration (AMD) is the leading cause
of blindness after age 55 in the industrialized world. AMD occurs in two major forms:
neovascular (wet) AMD and atrophic (dry) AMD. The neovascular (wet) form accounts for
90% of severe visual loss associated with AMD, even though only ~20% of individuals with
AMD develop the wet form. Clinical hallmarks of AMD include multiple drusen,
geographic atrophy, and choroidal neovascularization (CNV). In December, 2004, the FDA
approved Macugen (pegaptanib), a new class of ophthalmic drugs to specifically target and
block the effects of vascular endothelial growth factor (VEGF), for treatment of the wet
(neovascular) form of AMD (Ng et al., Nat Rev. Drug Discov 5:123-32 (2006)). Although
Macugen represents a promising new therapeutic option for a subgroup of AMD patients,
there remains a pressing need to develop additional treatments for this complex disease.
Multiple, independent lines of investigation implicate a central role for complement
activation in the pathogenesis of AMD. The pathogenesis of choroidal neovascularization
(CNV), the most serious form of AMD, may involve activation of complement pathways.
Over twenty-five years ago, Ryan described a laser-induced injury model of CNV in
animals (Ryan, S.J., Tr. Am. Opth. Soc. LXXVII:707-745, 1979). The model was initially
developed using rhesus monkeys, however, the same technology has since been used to
develop similar models of CNV in a variety of research animals, including the mouse
(Tobe et al., Am. J. Pathol. 153:1641-46, 1998). In this model, laser photocoagulation is
used to break Bruch's membrane, an act which results in the formation of CNV-like
membranes. The laser-induced model captures many of the important features of the human
condition (for a recent review, see Ambati et al., Survey Ophthalmology 48:257-293, 2003).
The laser-induced mouse model is now well established, and is used as an experimental basis
in a large, and ever increasing, number of research projects. It is generally accepted that the
laser-induced model shares enough biological similarity with CNV in humans that preclinical
studies of pathogenesis and drug inhibition using this model are relevant to CNV in humans.
Methods:
A MASP/- mouse was generated as described in Example 1 and backcrossed for
generations with C57Bl/6. The current study compared the results when MASP-2 (-/-)
and MASP-2 (+/+) male mice were evaluated in the course of laser-induced CNV, an
accelerated model of neovascular AMD focusing on the volume of laser-induced CNV by
scanning laser confocal microscopy as a measure of tissue injury and determination of levels
of VEGF, a potent angiogenic factor implicated in CNV, in the retinal pigment epithelium
(RPE)/choroids by ELISA after laser injury.
Induction of choroidal neovascularization (CNV): Laser photocoagulation (532
nm, 200 mW, 100 ms, 75µm; Oculight GL, Iridex, Mountain View, CA) was performed on
both eyes of each animal on day zero by a single individual masked to drug group
assignment. Laser spots were applied in a standardized fashion around the optic nerve, using
a slit lamp delivery system and a coverslip as a contact lens. The morphologic end point of
the laser injury was the appearance of a cavitation bubble, a sign thought to correlate with the
disruption of Bruch's membrane. The detailed methods and endpoints that were evaluated
are as follows.
Fluorescein Angiography: Fluorescein angiography was performed with a camera
and imaging system (TRC 50 1A camera; ImageNet 2.01 system; Topcon, Paramus , NJ) at 1
week after laser photocoagulation. The photographs were captured with a 20-D lens in
contact with the fundus camera lens after intraperitoneal injection of 0.1 ml of 2.5%
fluorescein sodium. A retina expert not involved in the laser photocoagulation or
angiography evaluated the fluorescein angiograms at a single sitting in masked fashion.
Volume of choroidal neovascularization (CNV): One week after laser injury, eyes
were enucleated and fixed with 4% paraformaldehyde for 30 min at 4ºC. Eye cups were
obtained by removing anterior segments and were washed three times in PBS, followed by
dehydration and rehydration through a methanol series. After blocking twice with buffer
(PBS containing 1% bovine serumalbumin and 0.5% Triton X-100) for 30 minutes at room
temperature, eye cups were incubated overnight at 4ºC with 0.5% FITC-isolectin B4 (Vector
laboratories, Burlingame, CA), diluted with PBS containing 0.2% BSA and 0.1% Triton
X-100, which binds terminal β-D-galactose residues on the surface of endothelial cells and
selectively labels the murine vasculature. After two washings with PBS containing 0.1%
Triton X-100, the neurosensory retina was gently detached and severed from the optic nerve.
Four relaxing radial incisions were made, and the remaining RPE –choroid-sclera complex
was flatmounted in antifade medium (Immu-Mount Vectashield Mounting Medium; Vector
Laboratories) and cover-slipped.
Flatmounts were examined with a scanning laser confocal microscope (TCS SP;
Leica, Heidelberg, Germany). Vessels were visualized by exciting with blue argon
wavelength (488 nm) and capturing emission between 515 and 545 nm. A 40X
oil-immersion objective was used for all imaging studies. Horizontal optical sections (1 µm
step) were obtained from the surface of the RPE-choroid-sclera complex. The deepest focal
plane in which the surrounding choroidal vascular network connecting to the lesion could be
identified was judged to be the floor of the lesion. Any vessel in the laser-targeted area and
superficial to this reference plane was judged as CNV. Images of each section were digitally
stored. The area of CNV-related fluorescence was measured by computerized image
analysis with the microscope software (TCS SP; Leica). The summation of whole
fluorescent area in each horizontal section was used as an index for the volume of CNV.
Imaging was performed by an operator masked to treatment group assignment.
Because the probability of each laser lesion developing CNV is influenced by the
group to which it belongs (mouse, eye, and laser spot), the mean lesion volumes were
compared using a linear mixed model with a split plot repeated-measures design. The whole
plot factor was the genetic group to which the animal belongs, whereas the split plot factor
was the eye. Statistical significance was determined at the 0.05 level. Post hoc comparisons
of means were constructed with a Bonferroni adjustment for multiple comparisons.
VEGF ELISA. At three days after injury by 12 laser spots, the RPE-choroid complex
was sonicated in lysis buffer (20 mM imidazole HCl, 10 mM KCl, 1 mM MgCL2, 10 mM
EGTA, 1% Triton X-100, 10 mM NaF, 1 mM Na molybdate, and 1 mM EDTA with protease
inhibitor) on ice for 15 min. VEGF protein levels in the supernatant were determined by an
ELISA kit (R&D Systems, Minneapolis, MN) that recognizes all splice variants, at 450 to
570 nm (Emax; Molecular Devices, Sunnyvale, CA), and normalized to total protein.
Duplicate measurements were performed in a masked fashion by an operator not involved in
photocoagulation, imaging, or angiography. VEGF numbers were represented as the mean
+/- SEM of at least three independent experiments and compared using the Mann-Whitney U
test. The null hypothesis was rejected at P<0.05.
RESULTS:
Assessment of VEGF Levels:
FIGURE 13A graphically illustrates the VEGF protein levels in RPE-choroid
complex isolated from C57Bl6 wildtype and MASP-2(-/-) mice at day zero. As shown in
FIGURE 13A, the assessment of VEGF levels indicate a decrease in baseline levels for
VEGF in the MASP-2 (-/-) mice versus the C57bl wildtype control mice. FIGURE 13B
graphically illustrates VEGF protein levels measured at day three following laser induced
injury. As shown in FIGURE 13B VEGF levels were significantly increased in the wildtype
(+/+) mice three days following laser induced injury, consistent with published studies
(Nozaki et al., Proc. Natl. Acad. Sci. USA 103:2328-33 (2006)). However, surprisingly very
low levels of VEGF were seen in the MASP-2 (-/-) mice.
Assessment of choroidal neovascularization (CNV):
In addition to the reduction in VEGF levels following laser induced macular
degeneration, CNV area was determined before and after laser injury. FIGURE 14
graphically illustrates the CNV volume measured in C57bl wildtype mice and MASP-2(-/-)
mice at day seven following laser induced injury. As shown in FIGURE 14, the MASP-2
(-/-) mice displayed about a 30% reduction in the CNV area following laser induced damage
at day seven in comparison to the wildtype control mice.
These findings indicate a reduction in VEGF and CNV as seen in the MASP (-/-)
mice versus the wildtype (+/+) control and that blockade of MASP-2 with an inhibitor would
have a preventive or therapeutic effect in the treatment of macular degeneration.
EXAMPLE 14
This Example demonstrates that thrombin activation can occur following lectin
pathway activation under physiological conditions, and demonstrates the extent of MASP-2
involvement. In normal rat serum, activation of the lectin pathway leads to thrombin
activation (assessed as thrombin deposition) concurrent with complement activation
(assessed as C4 deposition). As can be seen in FIGURES 15A and 15B, thrombin activation
in this system is inhibited by a MASP-2 blocking antibody (Fab2 format), exhibiting an
inhibition concentration-response curve (FIGURE 15B) that parallels that for complement
activation (FIGURE 15A). These data suggest that activation of the lectin pathway as it
occurs in trauma will lead to activation of both complement and coagulation systems in a
process that is entirely dependent on MASP-2. By inference, MASP2 blocking antibodies
may prove efficacious in mitigating cases of excessive systemic coagulation, e.g.,
disseminated intravascular coagulation, which is one of the hallmarks leading to mortality in
major trauma cases.
EXAMPLE 15
This Example provides results generated using a localized Schwartzman reaction
model of disseminated intravascular coagulation ("DIC") in MASP-2 -/- deficient and
MASP-2 +/+ sufficient mice to evaluate the role of lectin pathway in DIC.
Background/Rationale:
As described supra, blockade of MASP-2 inhibits lectin pathway activation and
reduces the generation of both anaphylatoxins C3a and C5a. C3a anaphylatoxins can be
shown to be potent platelet aggregators in vitro, but their involvement in vivo is less well
defined and the release of platelet substances and plasmin in wound repair may only
secondarily involve complement C3. In this Example, the role of the lectin pathway was
analyzed in MASP-2 (-/-) and WT (+/+) mice in order to address whether prolonged
elevation of C3 activation is necessary to generate disseminated intravascular coagulation.
Methods:
The MASP-2 (-/-) mice used in this study were generated as described in Example 1
and backcrossed for at least 10 generations with C57Bl/6.
The localized Schwartzman reaction model was used in this experiment. The
localized Schwartzman reaction (LSR) is a lipopolysaccharide (LPS) -induced response with
well-characterized contributions from cellular and humoral elements of the innate immune
system. Dependent of the LSR on complement is well established (Polak, L., et al., Nature
223:738-739 (1969); Fong J.S. et al., J Exp Med 134:642-655 (1971)). In the LSR model,
the mice were primed for 4 hours with TNF alpha (500 ng, intrascrotal), then the mice were
anaesthetized and prepared for intravital microscopy of the cremaster muscle. Networks of
post-capillary venules (15-60 µm diameter) with good blood flow (1-4 mm/s) were selected
for observation. Animals were treated with fluorescent antibodies to selectively label
neutrophils, or platelets. The network of vessels was sequentially scanned and images of all
vessels were digitally recorded of later analysis. After recording the basal state of the
microcirculation, mice received a single intravenous injection of LPS (100 µg), either alone
or with the agents listed below. The same network of vessels was then scanned every
minutes for 1 hour. Specific accumulation of fluorophores was identified by subtraction
of background fluorescence and enhanced by thresholding the image. The magnitude of
reactions was measured from recorded images. The primary measure of Schwartzman
reactions was aggregate data.
The studies compared the MASP-2 +/+ sufficient, or wild type, mice exposed to
either a known complement pathway depletory agent, cobra venom factor (CVF), or a
terminal pathway inhibitor (C5aR antagonist). The results (FIGURE 16A) demonstrate that
CVF as well as a C5aR antagonist both prevented the appearance of aggregates in the
vasculature. In addition, the MASP-2 -/- deficient mice (FIGURE 16B) also demonstrated
complete inhibition of the localized Schwartzman reaction, supporting lectin pathway
involvement. These results clearly demonstrate the role of MASP-2 in DIC generation and
support the use of MASP-2 inhibitors for the treatment and prevention of DIC.
EXAMPLE 16
This Example describes the analysis of MASP-2 (-/-) mice in a Murine Renal
Transplantation Model.
Background/Rationale:
The role of MASP-2 in the functional outcome of kidney transplantation was assessed
using a mouse model.
Methods:
The functional outcome of kidney transplantation was assessed using a single kidney
isograft into uninephrecomized recipient mice, with six WT (+/+) transplant recipients (B6),
and six MASP-2 (-/-) transplant recipients. To assess the function of the transplanted kidney,
the remaining native kidney was removed from the recipient 5 days after transplantation, and
renal function was assessed 24 hours later by measurement of blood urea nitrogen (BUN)
levels.
Results:
FIGURE 17 graphically illustrates the blood urea nitrogen (BUN) levels of the
kidney at 6 days post kidney transplant in the WT (+/+) recipients and the MASP-2 (-/-)
recipients. As shown in FIGURE 17, strongly elevated BUN levels were observed in the
WT (+/+) (B6) transplant recipients (normal BUN levels in mice are < 5 mM), indicating
renal failure. In contrast, MASP-2 (-/-) isograft recipient mice showed substantially lower
BUN levels, suggesting improved renal function. It is noted that these results were obtained
using grafts from WT (+/+) kidney donors, suggesting that the absence of a functional lectin
pathway in the transplant recipient alone is sufficient to achieve a therapeutic benefit.
Taken together, these results indicate that transient inhibition of the lectin pathway
via MASP-2 inhibition provides a method of reducing morbidity and delayed graft function
in renal transplantation, and that this approach is likely to be useful in other transplant
settings.
EXAMPLE 17
This Example demonstrates that MASP-2 (-/-) mice are resistant to septic shock in a
Murine Polymicrobial Septic Peritonitis Model.
Background/Rationale:
To evaluate the potential effects of MASP-2 (-/-) in infection, the cecal ligation and
puncture (CLP) model, a model of polymicrobial septic peritonitis was evaluated. This
model is thought to most accurately mimic the course of human septic peritonitis. The cecal
ligation and puncture (CLP) model is a model in which the cecum is ligated and punctured
by a needle, leading to continuous leakage of the bacteria into the abdominal cavity which
reach the blood through the lymph drainage and are then distributed into all the abdominal
organs, leading to multi-organ failure and septic shock (Eskandari et al., J Immunol
148(9):2724-2730 (1992)). The CLP model mimics the course of sepsis observed in patients
and induces an early hyper-inflammatory response followed by a pronounced hypoinflammatory phase. During this phase, the animals are highly sensitive to bacterial
challenges (Wichterman et al., J. Surg. Res. 29(2):189-201 (1980)).
Methods:
The mortality of polymicrobial infection using the cecal ligation and puncture (CLP)
model was measured in WT (+/+) (n=18) and MASP-2 (-/-) (n=16) mice. Briefly described,
MASP-2 deficient mice and their wild-type littermates were anaesthetized and the cecum
was exteriorized and ligated 30% above the distal end. After that, the cecum was punctured
once with a needle of 0.4 mm diameter. The cecum was then replaced into the abdominal
cavity and the skin was closed with clamps. The survival of the mice subjected to CLP was
monitored over a period of 14 days after CLP. A peritoneal lavage was collected in mice 16
hours post CLP to measure bacterial load. Serial dilutions of the peritoneal lavage were
prepared in PBS and inoculated in Mueller Hinton plates with subsequent incubation at 37°C
under anaerobic conditions for 24 hours after which bacterial load was determined.
The TNF-alpha cytokine response to the bacterial infection was also measured in the
WT (+/+) and MASP-2 (-/-) mice 16 hours after CLP in lungs and spleens via quantitative
real time polymerase chain reaction (qRT-PCR). The serum level of TNF-alpha 16 hours
after CLP in the WT (+/+) and MASP-2 (-/-) mice was also quantified by sandwich ELISA.
Results:
FIGURE 18 graphically illustrates the percentage survival of the CLP treated
animals as a function of the days after the CLP procedure. As shown in FIGURE 18, the
lectin pathway deficiency in the MASP-2 (-/-) mice does not increase the mortality of mice
after polymicrobial infection using the cecal ligation and puncture model as compared to WT
(+/+) mice. However, as shown in FIGURE 19, MASP-2 (-/-) mice showed a significantly
higher bacterial load (approximately a 1000-fold increase in bacterial numbers) in peritoneal
lavage after CLP when compared to their WT (+/+) littermates. These results indicate that
MASP-2 (-/-) deficient mice are resistant to septic shock. The reduced bacterial clearance in
MASP-2 deficient mice in this model may be due to an impaired C3b mediated phagocytosis,
as it was demonstrated that C3 deposition is MASP-2 dependent.
It was determined that the TNF-alpha cytokine response to the bacterial infection was
not elevated in the MASP-2 (-/-) mice as compared to the WT (+/+) controls (data not
shown). It was also determined that there was a significantly higher serum concentration of
TNF-alpha in WT (+/+) mice 16 hours after CLP in contrast to MASP-2 (-/-) mice, where the
serum level of TNF-alpha remained nearly unaltered. These results suggest that the intense
inflammatory response to the septic condition was tempered in MASP-2 (-/-) mice and
allowed the animals to survive in the presence of higher bacterial counts.
Taken together, these results demonstrate the potential deleterious effects of lectin
pathway complement activation in the case of septicemia and the increased mortality in
patients with overwhelming sepsis. These results further demonstrate that MASP-2
deficiency modulates the inflammatory immune response and reduces the expression levels
of inflammatory mediators during sepsis. Therefore, it is believed that inhibition of MASP-2
(-/-) by administration of inhibitory monoclonal antibodies against MASP-2 would be
effective to reduce the inflammatory response in a subject suffering from septic shock.
EXAMPLE 18
This Example describes analysis of MASP-2 (-/-) mice in a Murine Intranasal
Infectivity Model.
Background/Rationale:
Pseudomonas aeruginosa is a Gram negative opportunistic human bacterial pathogen
that causes a wide range of infections, particularly in immune-compromised individuals. It is
a major source of acquired nosocomial infections, in particular hospital-acquired pneumonia.
It is also responsible for significant morbidity and mortality in cystic fibrosis (CF) patients.
P. aeruginosa pulmonary infection is characterized by strong neutrophil recruitment and
significant lung inflammation resulting in extensive tissue damage (Palanki M.S. et al.,
J. Med. Chem 51:1546-1559 (2008)).
In this Example, a study was undertaken to determine whether the removal of the
lectin pathway in MASP-2 (-/-) mice increases the susceptibility of the mice to bacterial
infections.
Methods:
Twenty-two WT (+/+) mice, twenty-two MASP-2 (-/-) mice, and eleven C3 (-/-) mice
were challenged with intranasal administration of P. aeruginosa bacterial strain. The mice
were monitored over the six days post-infection and Kaplan-Mayer plots were constructed
showing percent survival.
Results:
FIGURE 20 is a Kaplan-Mayer plot of the percent survival of WT (+/+), MASP-2
(-/-) or C3 (-/-) mice six days post-infection. As shown in FIGURE 20, no differences were
observed in the MASP-2 (-/-) mice versus the WT (+/+) mice. However, removal of the
classical (C1q) pathway in the C3 (-/-) mice resulted in a severe susceptibility to bacterial
infection. These results demonstrate that MASP-2 inhibition does not increase susceptibility
to bacterial infection, indicating that it is possible to reduce undesirable inflammatory
complications in trauma patients by inhibiting MASP-2 without compromising the patient's
ability to fight infections using the classical complement pathway.
EXAMPLE 19
This Example describes the pharmacodynamic analysis of representative high affinity
anti-MASP-2 Fab2 antibodies that were identified as described in Example 10.
Background/Rationale:
As described in Example 10, in order to identify high-affinity antibodies that block
the rat lectin pathway, rat MASP-2 protein was utilized to pan a phage display library. This
library was designed to provide for high immunological diversity and was constructed using
entirely human immunoglobin gene sequences. As described in Example 10, approximately
250 individual phage clones were identified that bound with high affinity to the rat MASP-2
protein by ELISA screening. Sequencing of these clones identified 50 unique MASP-2
antibody encoding phage. Fab2 protein was expressed from these clones, purified and
analyzed for MASP-2 binding affinity and lectin complement pathway functional inhibition.
As shown in TABLE 6 of Example 10, 17 anti-MASP-2 Fab2s with functional
blocking activity were identified as a result of this analysis (a 34% hit rate for blocking
antibodies). Functional inhibition of the lectin complement pathway by Fab2s was apparent
at the level of C4 deposition, which is a direct measure of C4 cleavage by MASP-2.
Importantly, inhibition was equally evident when C3 convertase activity was assessed,
demonstrating functional blockade of the lectin complement pathway. The 17 MASP-2
blocking Fab2s identified as described in Example 10 potently inhibit C3 convertase
formation with IC50 20 values equal to or less than 10 nM. Eight of the 17 Fab2s identified
have IC50 values in the sub-nanomolar range. Furthermore, all 17 of the MASP-2 blocking
Fab2s gave essentially complete inhibition of the C3 convertase formation in the lectin
pathway C3 convertase assay, as shown in FIGURES 8A-C, and summarized in TABLE 6 of
Example 10. Moreover, each of the 17 blocking anti-MASP-2 Fab2s shown in TABLE 6
potently inhibit C3b generation (>95%), thus demonstrating the specificity of this assay for
lectin pathway C3 convertase.
Rat IgG2c and mouse IgG2a full-length antibody isotype variants were derived from
Fab2 #11. This Example describes the in vivo characterization of these isotypes for
pharmacodynamic parameters.
Methods:
As described in Example 10, rat MASP-2 protein was utilized to pan a Fab phage
display library, from which Fab2#11 was identified. Rat IgG2c and mouse IgG2a full-length
antibody isotype variants were derived from Fab2 #11. Both rat IgG2c and mouse IgG2a full
length antibody isotypes were characterized in vivo for pharmacodynamic parameters as
follows.
In vivo study in mice:
A pharmacodynamic study was carried out in mice to investigate the effect of antiMASP-2 antibody dosing on the plasma lectin pathway activity in vivo. In this study, C4
deposition was measured ex vivo in a lectin pathway assay at various time points following
subcutaneous (sc) and intraperitoneal (ip) administration of 0.3 mg/kg or 1.0 mg/kg of the
mouse anti-MASP-2 MoAb (mouse IgG2a full-length antibody isotype derived from
Fab2#11).
FIGURE 21 graphically illustrates lectin pathway specific C4b deposition, measured
ex vivo in undiluted serum samples taken from mice (n=3 mice/group) at various time points
after subcutaneous dosing of either 0.3 mg/kg or 1.0 mg/kg of the mouse anti-MASP-2
MoAb. Serum samples from mice collected prior to antibody dosing served as negative
controls (100% activity), while serum supplemented in vitro with 100 nM of the same
blocking anti-MASP-2 antibody was used as a positive control (0% activity).
The results shown in FIGURE 21 demonstrate a rapid and complete inhibition of
C4b deposition following subcutaneous administration of 1.0 mg/kg dose of mouse antiMASP-2 MoAb. A partial inhibition of C4b deposition was seen following subcutaneous
administration of 0.3 mg/kg dose of mouse anti-MASP-2 MoAb.
The time course of lectin pathway recovery was followed for three weeks following a
single ip administration of mouse anti-MASP-2 MoAb at 0.6 mg/kg in mice. As shown in
FIGURE 22, a precipitous drop in lectin pathway activity occurred post antibody dosing
followed by complete lectin pathway inhibition that lasted for about 7 days after ip
administration. Slow restoration of lectin
These results demonstrate that the mouse anti-MASP-2 Moab derived from Fab2 #11
inhibits the lectin pathway of mice in a dose-responsive manner when delivered systemically.
EXAMPLE 20
This Example describes analysis of the mouse anti-MASP-2 Moab derived from Fab2
#11 for efficacy in a mouse model for age-related macular degeneration.
Background/Rationale:
As described in Example 10, rat MASP-2 protein was utilized to pan a Fab phage
display library, from which Fab2#11 was identified as a functionally active antibody. Full
length antibodies of the rat IgG2c and mouse IgG2a isotypes were generated from Fab2 #11.
The full length anti-MASP-2 antibody of the mouse IgG2a isotype was characterized for
pharmacodynamic parameters as described in Example 19. In this Example, the mouse anti10 MASP-2 full-length antibody derived from Fab2 #11 was analyzed in the mouse model of
age-related macular degeneration (AMD), described by Bora P.S. et al, J Immunol 174:491-
497 (2005).
Methods:
The mouse IgG2a full-length anti-MASP-2 antibody isotype derived from Fab2 #11
as described in Example 19, was tested in the mouse model of age-related macular
degeneration (AMD) as described in Example 13 with the following modifications.
Administration of mouse-anti-MASP-2 MoAbs
Two different doses (0.3 mg/kg and 1.0 mg/kg) of mouse anti-MASP-2 MoAb along
with an isotype control MoAb treatment were injected ip into WT (+/+) mice (n= 8 mice per
group) 16 hours prior to CNV induction
Induction of choroidal neovascularization (CNV)
The induction of choroidal neovascularization (CNV) and measurement of the
volume of CNV was carried out using laser photocoagulation as described in Example 13.
Results:
FIGURE 23 graphically illustrates the CNV area measured at 7 days post laser injury
in mice treated with either isotype control MoAb, or mouse anti-MASP-2 MoAb (0.3 mg/kg
and 1.0 mg/kg). As shown in FIGURE 23, in the mice pre-treated with 1.0 mg/kg
anti-MASP-2 MoAb, a statistically significant (p <0.01) approximately 50% reduction in
CNV was observed seven days post-laser treatment. As further shown in FIGURE 23, it
was observed that a 0.3 mg/kg dose of anti-MASP-2 MoAb was not efficacious in reducing
CNV. It is noted that the 0.3 mg/kg dose of anti-MASP-2 MoAb was shown to have a partial
and transient inhibition of C4b deposition following subcutaneous administration, as
described in Example 19 and shown in FIGURE 21.
The results described in this Example demonstrate that blockade of MASP-2 with an
inhibitor, such as anti-MASP-2 MoAb, has a preventative and/or therapeutic effect in the
treatment of macular degeneration. It is noted that these results are consistent with the
results observed in the study carried out in the MASP-2 (-/-) mice, described in Example 13,
in which a 30% reduction in the CNV 7 days post-laser treatment was observed in MASP-2
(-/-) mice in comparison to the wild-type control mice. Moreover, the results in this Example
further demonstrate that systemically delivered anti-MASP-2 antibody provides local
therapeutic benefit in the eye, thereby highlighting the potential for a systemic route of
administration to treat AMD patients. In summary, these results provide evidence supporting
the use of MASP-2 MoAb in the treatment of AMD.
EXAMPLE 21
This Example demonstrates that MASP-2 deficient mice are protected from Neisseria
meningitidis induced mortality after infection with N. meningitidis and have enhanced
clearance of bacteraemia as compared to wild type control mice.
Rationale: Neisseria meningitidis is a heterotrophic gram-negative diplococcal
bacterium known for its role in meningitis and other forms of meningococcal disease such as
meningococcemia. N. meningitidis is a major cause of morbidity and mortality during
childhood. Severe complications include septicaemia, Waterhouse-Friderichsen syndrome,
adrenal insufficiency and disseminated intravascular coagulation (DIC). See e.g., Rintala E.
et al., Critical Care Medicine 28(7):2373-2378 (2000). In this Example, the role of the lectin
pathway was analyzed in MASP-2 (-/-) and WT (+/+) mice in order to address whether
MASP-2 deficient mice would be susceptible to N. meningitidis induced mortality.
Methods:
MASP-2 knockout mice were generated as described in Example 1 and backcrossed
for at least 10 generations with C57Bl/6. 10 week old MASP-2 KO mice (n=10) and wild
type C57/B6 mice (n=10) were innoculated by intravenous injection with either a dosage of
5x108 cfu/100 μl, 2x108 cfu/100 μl or 3x107 30 cfu/100 μl of Neisseria meningitidis Serogroup
A Z2491 in 400 mg/kg iron dextran. Survival of the mice after infection was monitored over
a 72 hour time period. Blood samples were taken from the mice at hourly intervals after
infection and analyzed to determine the serum level (log cfu/ml) of N. meningitidis in order
to verify infection and determine the rate of clearance of the bacteria from the serum.
Results:
FIGURE 24A graphically illustrates the percent survival of MASP-2 KO and WT
mice after administration of an infective dose of 5x108/100 μl cfu N. meningitidis. As shown
in FIGURE 24A, after infection with the highest dose of 5x108/100 μl cfu N. meningitidis,
100% of the MASP-2 KO mice survived throughout the 72 hour period after infection. In
contrast, only 20% of the WT mice were still alive 24 hours after infection. These results
demonstrate that MASP-2 deficient mice are protected from N. meningitidis induced
mortality.
FIGURE 24B graphically illustrates the log cfu/ml of N. meningitidis recovered at
different time points in blood samples taken from the MASP-2 KO and WT mice infected
with 5x108 cfu/100 μl N. meningitidis. As shown in FIGURE 24B, in WT mice the level of
N. meningitidis in the blood reached a peak of about 6.5 log cfu/ml at 24 hours after infection
and dropped to zero by 48 hours after infection. In contrast, in the MASP-2 KO mice, the
level of N. meningitidis reached a peak of about 3.5 log cfu/ml at 6 hours after infection and
dropped to zero by 36 hours after infection.
FIGURE 25A graphically illustrates the percent survival of MASP-2 KO and WT
mice after infection with 2x108 20 cfu/100 μl N. meningitidis. As shown in FIGURE 25A,
after infection with the dose of 2x108 cfu/100 μl N. meningitidis, 100% of the MASP-2 KO
mice survived throughout the 72 hour period after infection. In contrast, only 80% of the
WT mice were still alive 24 hours after infection. Consistent with the results shown in
FIGURE 24A, these results further demonstrate that MASP-2 deficient mice are protected
from N. meningitidis induced mortality.
FIGURE 25B graphically illustrates the log cfu/ml of N. meningitidis recovered at
different time points in blood samples taken from the WT mice infected with 2x108 cfu/100
μl N. meningitidis. As shown in FIGURE 25B, the level of N. meningitidis in the blood of
WT mice infected with 2x108 cfu reached a peak of about 4 log cfu/ml at 12 hours after
infection and dropped to zero by 24 hours after infection. FIGURE 25C graphically
illustrates the log cfu/ml of N. meningitidis recovered at different time points in blood
samples taken from the MASP-2 KO mice infected with 2x108 cfu/100 μl N. meningitidis.
As shown in FIGURE 25C, the level of N. meningitidis in the blood of MASP-2 KO mice
infected with 2x108 cfu reached a peak level of about 3.5 log cfu/ml at 2 hours after infection
and dropped to zero at 3 hours after infection. Consistent with the results shown in
FIGURE 24B, these results demonstrate that although the MASP-2 KO mice were infected
with the same dose of N. meningitidis as the WT mice, the MASP-2 KO mice have enhanced
clearance of bacteraemia as compared to WT.
The percent survival of MASP-2 KO and WT mice after infection with the lowest
dose of 3x107 10 cfu/100 μl N. meningitidis was 100% at the 72 hour time period (data not
shown).
Discussion
These results show that MASP-2 deficient mice are protected from N. meningitidis
induced mortality and have enhanced clearance of bacteraemia as compared to the WT mice.
Therefore, in view of these results, it is expected that therapeutic application of MASP-2
inhibitors, such as MASP-2 MoAb, would be expected to be efficacious to treat, prevent or
mitigate the effects of infection with N. meningitidis bacteria (i.e., sepsis and DIC). Further,
these results indicate that therapeutic application of MASP-2 inhibitors, such as MASP-2
MoAb would not predispose a subject to an increased risk to contract N. meningitidis
infections.
EXAMPLE 22
This Example describes the discovery of novel lectin pathway mediated and MASP-2
dependent C4-bypass activation of complement C3.
Rationale:
The principal therapeutic benefit of utilizing inhibitors of complement activation to
limit myocardial ischemia/reperfusion injury (MIRI) was convincingly demonstrated in an
experimental rat model of myocardial infarction two decades ago: Recombinant sCR1, a
soluble truncated derivative of the cell surface complement receptor type-1 (CR1), was given
intravenously and its effect assessed in a rat in vivo model of MIRI. Treatment with sCR1
reduced infarct volume by more than 40% (Weisman, H.F., et al., Science 249:146-151
(1990)). The therapeutic potential of this recombinant inhibitor was subsequently
demonstrated in a clinical trial showing that the administration of sCR1 in patients with MI
prevented contractile failure in the post-ischemic heart (Shandelya, S., et al., Circulation
87:536-546 (1993)). The primary mechanism leading to the activation of complement in
ischemic tissue, however, has not been ultimately defined, mainly due to the lack of
appropriate experimental models, the limited understanding of the molecular processes that
lead to complement activation of oxygen-deprived cells, and the cross-talk and synergisms
between the different complement activation pathways.
As a fundamental component of the immune response, the complement system
provides protection against invading microorganisms through both antibody-dependent and -
independent mechanisms. It orchestrates many cellular and humoral interactions within the
immune response, including chemotaxis, phagocytosis, cell adhesion, and B-cell
differentiation. Three different pathways initiate the complement cascade: the classical
pathway, the alternative pathway, and the lectin pathway. The classical pathway recognition
subcomponent C1q binds to a variety of targets - most prominently immune complexes - to
initiate the step-wise activation of associated serine proteases, C1r and C1s, providing a
major mechanism for pathogen and immune complex clearance following engagement by the
adaptive immune system. Binding of C1q to immune complexes converts the C1r zymogen
dimer into its active form to cleave and thereby activate C1s. C1s translates C1q binding
into complement activation in two cleavage steps: It first converts C4 into C4a and C4b and
then cleaves C4b-bound C2 to form the C3 convertase C4b2a. This complex converts the
abundant plasma component C3 into C3a and C3b. Accumulation of C3b in close proximity
of the C4b2a complex shifts the substrate specificity for C3 to C5 to form the C5 convertase
C4b2a(C3b)n. The C3 and C5 convertase complexes generated via classical pathway
activation are identical to those generated through the lectin pathway activation route. In the
alternative pathway, spontaneous low-level hydrolysis of component C3 results in deposition
of protein fragments onto cell surfaces, triggering complement activation on foreign cells,
while cell-associated regulatory proteins on host tissues avert activation, thus preventing self30 damage. Like the alternative pathway, the lectin pathway may be activated in the absence of
immune complexes. Activation is initiated by the binding of a multi-molecular lectin
pathway activation complex to Pathogen-Associated Molecular Patterns (PAMPs), mainly
carbohydrate structures present on bacterial, fungal or viral pathogens or aberrant
glycosylation patterns on apoptotic, necrotic, malignant or oxygen-deprived cells (Collard,
C.D., et al., Am. J. Pathol. 156:1549-1556 (2000); Walport, M.J., N. Engl. J. Med. 344:1058-
1066 (2001); Schwaeble, W., et al., Immunobiology 205:455-466 (2002); and Fujita, T., Nat.
Rev. Immunol. 2:346-353 (2002)).
Mannan-binding lectin (MBL) was the first carbohydrate recognition subcomponent
shown to form complexes with a group of novel serine proteases, named MBL-associated
Serine Proteases (MASPs) and numbered according to the sequence of their discovery (i.e.,
MASP-1, MASP-2 and MASP-3). In man, lectin pathway activation complexes can be
formed with four alternative carbohydrate recognition subcomponents with different
carbohydrate binding specificities, i.e., MBL 2, and three different members of the ficolin
family, namely L-Ficolin, H-ficolin and M-ficolin and MASPs. Two forms of MBL, MBL A
and MBL C, and ficolin-A form lectin activation pathway complexes with MASPs in mouse
and rat plasma. We have previously cloned and characterised MASP-2 and an additional
truncated MASP-2 gene product of 19 kDa, termed MAp19 or sMAP, in human, mouse and
rat (Thiel, S., et al., Nature 386:506-510 (1997);. Stover, C.M., et al., J. Immunol. 162:3481-
3490 (1999); Takahashi, M., et al., Int. Immunol. 11:859-863 (1999); and Stover, C.M., et al.,
J. Immunol. 163:6848-6859 (1999)). MAp19/ sMAP is devoid of protease activity, but may
regulate lectin pathway activation by competing for the binding of MASPs to carbohydrate
recognition complexes (Iwaki, D. et al., J. Immunol. 177:8626-8632 (2006)).
There is evidence suggesting that of the three MASPs, only MASP-2 is required to
translate binding of the lectin pathway recognition complexes into complement activation
(Thiel, S., et al. (1997); Vorup-Jensen, T., et al., J. Immunol. 165:2093-2100 (2000); Thiel,
S., et al., J. Immunol. 165:878-887 (2000); Rossi, V., et al., J. Biol. Chem. 276:40880-40887
(2001)). This conclusion is underlined by the phenotype of a most recently described mouse
strain deficient in MASP-1 and MASP-3. Apart from a delay in the onset of lectin pathway
mediated complement activation in vitro –MASP-1/3 deficient mice retain lectin pathway
functional activity. Reconstitution of MASP-1 and MASP-3 deficient serum with
recombinant MASP-1 overcomes this delay in lectin pathway activation implying that
MASP-1 may facilitate MASP-2 activation (Takahashi, M., et al., J. Immunol. 180:6132-
6138 (2008)). A most recent study has shown that MASP-1 (and probably also MASP-3) are
required to convert the alternative pathway activation enzyme Factor D from its zymogen
form into its enzymatically active form (Takahashi, M., et al., J. Exp. Med. 207:29-37
(2010)). The physiological importance of this process is underlined by the absence of
alternative pathway functional activity in plasma of MASP-1/3 deficient mice.
The recently generated mouse strains with combined targeted deficiencies of the
lectin pathway carbohydrate recognition subcomponents MBL A and MBL C may still
initiate lectin pathway activation via the remaining murine lectin pathway recognition
subcomponent ficolin A (Takahashi, K., et al., Microbes Infect. 4:773-784 (2002)). The
absence of any residual lectin pathway functional activity in MASP-2 deficient mice delivers
a conclusive model to study the role of this effector arm of innate humoral immunity in
health and disease.
The availability of C4 and MASP-2 deficient mouse strains allowed us to define a
novel lectin pathway specific, but MASP-2 dependent, C4-bypass activation route of
complement C3. The essential contribution of this novel lectin pathway mediated C4-bypass
activation route towards post-ischemic tissue loss is underlined by the prominent protective
phenotype of MASP-2 deficiency in MIRI while C4-deficient mice tested in the same model
show no protection.
In this Example, we describe a novel lectin pathway mediated and MASP-2
dependent C4-bypass activation of complement C3. The physiological relevance of this new
activation route is established by the protective phenotype of MASP-2 deficiency in an
experimental model of myocardial ischemia/reperfusion injury (MIRI), where C4 deficient
animals were not protected.
Methods:
MASP-2 deficient mice show no gross abnormalities. MASP-2 deficient mice
were generated as described in Example 1. Both heterozygous (+/-) and homozygous (-/-)
MASP-2 deficient mice are healthy and fertile, and show no gross abnormalities. Their life
expectancy is similar to that of their WT littermates (>18 months). Prior to studying the
phenotype of these mice in experimental models of disease, our MASP/- line was
backcrossed for eleven generations onto a C57BL/6 background. The total absence of
MASP-2 mRNA was confirmed by Northern blotting of poly A+ selected liver RNA
preparations, while the 1.2kb mRNA encoding MAp19 or sMAP (a truncated alternative
splicing product of the MASP2 gene) is abundantly expressed.
qRT-PCR analysis using primer pairs specific for either the coding sequence for the
serine protease domain of MASP-2 (B chain) or the remainder of the coding sequence for the
A-chain showed that no B chain encoding mRNA is detectable in MASP-2 -/- 5 mice while the
abundance of the disrupted A chain mRNA transcript was significantly increased. Likewise,
the abundance of MAp19/sMAP encoding mRNA is increased in MASP-2 +/- and MASP-2 -/-
mice. Plasma MASP-2 levels, determined by ELISA for 5 animals of each genotype, were
300ng/ml for WT controls (range 260-330ng/ml), 360ng/ml for heterozygous mice (range
330-395ng/ml) and undetectable inMASP-2 -/- 10 mice. Using qRT-PCR, mRNA expression
profiles were established demonstrating that MASP/-mice express mRNA for MBL A,
MBL C, ficolin A, MASP-1, MASP-3, C1q, C1rA, C1sA, Factor B, Factor D, C4, and C3 at
an abundance similar to that of their MASP-2 sufficient littermates (data not shown).
Plasma C3 levels of MASP/- (n=8) and MASP-2+/+ (n=7) littermates were
measured using a commercially available mouse C3 ELISA kit (Kamiya, Biomedical,
Seattle, WA). C3 levels of MASP-2 deficient mice (average 0.84 mg/ml, +/- 0.34) were
similar to those of the WT controls (average 0.92, +/- 0.37).
Results:
MASP-2 is essential for lectin pathway functional activity.
As described in Example 2 and shown in FIGURE 5, the in vitro analyses of MASP2-/-plasma showed a total absence of lectin pathway functional activity on activating
Mannan- and Zymosan-coated surfaces for the activation of C4. Likewise, neither lectin
pathway-dependent C4 nor C3 cleavage was detectable in MASP/-plasma on surfaces
coated with N-acetyl glucosamine, which binds and triggers activation via MBL A, MBL C
and ficolin A (data not shown).
The analyses of sera and plasma of MASP/-mice clearly demonstrated that MASP2 is essentially required to activate complement via the lectin pathway. The total deficiency
of lectin pathway functional activity, however, leaves the other complement activation
pathways intact: MASP/-plasma can still activate complement via the classical (FIGURE
26A) and the alternative pathway (FIGURE 26B). In FIGURE 26A and 26B, the symbol
"*" symbol indicates serum from WT (MASP-2 (+/+)); the symbol "●" indicates serum from
WT (C1q depleted); the symbol "□" indicates serum from MASP-2 (-/-); and the symbol "∆"
indicates serum from MASP-2 (-/-) (C1q depleted).
FIGURE 26A graphically illustrates that MASP/- mice retain a functional
classical pathway: C3b deposition was assayed on microtiter plates coated with immune
complexes (generated in situ by coating with BSA then adding goat anti-BSA IgG).
FIGURE 26B graphically illustrates MASP-2 deficient mice retain a functional alternative
pathway: C3b deposition was assayed on Zymosan coated microtiter plates under conditions
that permit only alternative pathway activation (buffer containing Mg2+ and EGTA). Results
shown in FIGURE 26A and FIGURE 26B are means of duplicates and are typical of three
independent experiments. Same symbols for plasma sources were used throughout. These
results show that a functional alternative pathway is present in MASP-2 deficient mice, as
evidenced in the results shown in FIGURE 26B under experimental conditions designed to
directly trigger the alternative pathway, while inactivating both the classical pathway and
lectin pathway.
The lectin pathway of complement activation critically contributes to
inflammatory tissue loss in myocardial ischemia/reperfusion injury (MIRI).
In order to study the contribution of lectin pathway functional activity to MIRI, we
compared MASP/-mice and WT littermate controls in a model of MIRI following transient
ligation and reperfusion of the left anterior descending branch of the coronary artery (LAD).
The presence or absence of complement C4 has no impact on the degree of ischemic tissue
loss in MIRI. We assessed the impact of C4 deficiency on infarct sizes following
experimental MIRI. As shown in FIGURE 27A and FIGURE 27B, identical infarct sizes
were observed in both C4-deficient mice and their WT littermates. FIGURE 27A graphically
illustrates MIRI-induced tissue loss following LAD ligation and reperfusion in C4-/- mice
(n=6) and matching WT littermate controls (n=7). FIGURE 27B graphically illustrates INF
as a function of AAR, clearly demonstrating that C4-/- mice are as susceptible to MIRI as
their WT controls (dashed line).
These results demonstrate that C4 deficient mice are not protected from MIRI. This
result was unexpected, as it is in conflict with the widely accepted view that the major C4
activation fragment, C4b, is an essential component of the classical and the lectin pathway
C3 convertase C4b2a. We therefore assessed whether a residual lectin pathway specific
activation of complement C3 can be detected in C4-deficient mouse and human plasma.
The lectin pathway can activate complement C3 in absence of C4 via a novel
MASP-2 dependent C4-bypass activation route.
Encouraged by historical reports indicating the existence of a C4-bypass activation
route in C4-deficient guinea pig serum (May, J.E., and M. Frank, J. Immunol. 111:1671-1677
(1973)), we analyzed whether C4-deficient mice may have residual classical or lectin
pathway functional activity and monitored activation of C3 under pathway-specific assay
conditions that exclude contributions of the alternative pathway.
C3b deposition was assayed on Mannan-coated microtiter plates using re-calcified
plasma at plasma concentrations prohibitive for alternative pathway activation (1.25% and
below). While no cleavage of C3 was detectable in C4-deficient plasma tested for classical
pathway activation (data not shown), a strong residual C3 cleavage activity was observed in
C4-deficient mouse plasma when initiating complement activation via the lectin pathway.
The lectin pathway dependence is demonstrated by competitive inhibition of C3 cleavage
following preincubation of C4-deficient plasma dilutions with soluble Mannan (see
FIGURE 28A). As shown in FIGURE 28A-D, MASP-2 dependent activation of C3 was
observed in the absence of C4. FIGURE 28A graphically illustrates C3b deposition by
C4+/+ (crosses) and C4-/- (open circles) mouse plasma. Pre-incubating the C4-/- plasma
with excess (1 µg/ml) fluid-phase Mannan prior to the assay completely inhibits C3
deposition (filled circles). Results are typical of 3 independent experiments. FIGURE 28B
graphically illustrates the results of an experiment in which wild-type, MASP-2 deficient
(open squares) and C4-/-mouse plasma (1%) was mixed with various concentrations of antirat MASP-2 mAbM11 (abscissa) and C3b deposition assayed on Mannan-coated plates.
Results are means (± SD) of 4 assays (duplicates of 2 of each type of plasma). FIGURE 28C
graphically illustrates the results of an experiment in which Human plasma: pooled NHS
(crosses), C4-/- plasma (open circles) and C4-/- plasma pre-incubated with 1 µg/ml Mannan
(filled circles). Results are representative of three independent experiments. FIGURE 28D
graphically illustrates that inhibition of C3b deposition in C4 sufficient and C4 deficient
human plasma (1%) by anti-human MASP-2 mAbH3 (Means ± SD of triplicates). As shown
in FIGURE 28B, no lectin pathway-dependent C3 activation was detected in MASP/-
plasma assayed in parallel, implying that this C4-bypass activation route of C3 is MASP-2
dependent.
To further corroborate these findings, we established a series of recombinant
inhibitory mAbs isolated from phage display antibody libraries by affinity screening against
recombinant human and rat MASP-2A (where the serine residue of the active protease
domain was replaced by an alanine residue by site-directed mutagenesis to prevent autolytic
degradation of the antigen). Recombinant antibodies against MASP-2 (AbH3 and AbM11)
were isolated from Combinatorial Antibody Libraries (Knappik, A., et al., J. Mol. Biol.
296:57-86 (2000)), using recombinant human and rat MASP-2A as antigens (Chen, C.B. and
Wallis, J. Biol. Chem. 276:25894-25902 (2001)). An anti-rat Fab2 fragment that potently
inhibited lectin pathway-mediated activation of C4 and C3 in mouse plasma (IC50~1 nM)
was converted to a full-length IgG2a antibody. Polyclonal anti-murine MASP-2A antiserum
was raised in rats. These tools allowed us to confirm MASP-2 dependency of this novel
lectin pathway specific C4-bypass activation route of C3, as further described below.
As shown in FIGURE 28B, M211, an inhibitory monoclonal antibody which
selectively binds to mouse and rat MASP-2 inhibited the C4-bypass activation of C3 in C4-
deficient mouse as well as C3 activation of WT mouse plasma via the lectin pathway in a
concentration dependent fashion with similar IC50 values. All assays were carried out at
high plasma dilutions rendering the alternative pathway activation route dysfunctional (with
the highest plasma concentration being 1.25%).
In order to investigate the presence of an analogous lectin pathway specific C4-
bypass activation of C3 in humans, we analyzed the plasma of a donor with an inherited
deficiency of both human C4 genes (i.e., C4A and C4B), resulting in total absence of C4
(Yang, Y., et al., J. Immunol. 173:2803-2814 (2004)). FIGURE 28C shows that this
patient's plasma efficiently activates C3 in high plasma dilutions (rendering the alternative
activation pathway dysfunctional). The lectin pathway specific mode of C3 activation on
Mannan-coated plates is demonstrated in murine C4-deficient plasma (FIGURE 28A) and
human C4 deficient plasma (FIGURE 28C) by adding excess concentrations of fluid-phase
Mannan. The MASP-2 dependence of this activation mechanism of C3 in human C4-
deficient plasma was assessed using AbH3, a monoclonal antibody that specifically binds to
human MASP-2 and ablates MASP-2 functional activity. As shown in FIGURE 28D, AbH3
inhibited the deposition of C3b (and C3dg) in both C4-sufficient and C4-deficient human
plasma with comparable potency.
In order to assess a possible role of other complement components in the C4-bypass
activation of C3, we tested plasma of MASP-1/3-/-and Bf/C2-/-mice alongside MASP/-,
C4-/- and C1q-/- plasma (as controls) under both lectin pathway specific and classical
pathway specific assay conditions. The relative amount of C3 cleavage was plotted against
the amount of C3 deposited when using WT plasma.
FIGURE 29A graphically illustrates a comparative analysis of C3 convertase activity
in plasma from various complement deficient mouse strains tested either under lectin
activation pathway or classical activation pathway specific assay conditions. Diluted plasma
samples (1%) of WT mice (n=6), MASP/-mice (n=4), MASP-1/3-/- mice (n=2), C4-/-
mice (n=8), C4/MASP-1/3-/- mice (n=8), Bf/C2-/- (n=2) and C1q-/- mice (n=2) were tested
in parallel. Reconstitution of Bf/C2-/- plasma with 2.5µg/ml recombinant rat C2 (Bf/C2-/-
+C2) restored C3b deposition. Results are means (±SD). **p<0.01 (compared to WT
plasma). As shown in FIGURE 29A, substantial C3 deposition is seen in C4-/- plasma
tested under lectin pathway specific assay conditions, but not under classical pathway
specific conditions. Again, no C3 deposition was seen in MASP-2 deficient plasma via the
lectin pathway activation route, while the same plasma deposited C3 via the classical
pathway. In MASP-1/3-/- plasma, C3 deposition occurred in both lectin and classical
pathway specific assay conditions. No C3 deposition was seen in plasma with a combined
deficiency of C4 and MASP-1/3, either using lectin pathway or classical pathway specific
conditions. No C3 deposition is detectable in C2/Bf-/- plasma, either via the lectin pathway,
or via the classical pathway. Reconstitution of C2/Bf-/- mouse plasma with recombinant C2,
however, restored both lectin pathway and classical pathway-mediated C3 cleavage. The
assay conditions were validated using C1q-/- plasma.
FIGURE 29B graphically illustrates time-resolved kinetics of C3 convertase activity
in plasma from various complement deficient mouse strains WT, fB-/-, C4-/-, MASP-1/3-/-,
and MASP/-plasma, tested under lectin activation pathway specific assay conditions (1%
plasma, results are typical of three independent experiments). As shown in FIGURE 29B,
while no C3 cleavage was seen in MASP/-plasma, fB-/- plasma cleaved C3 with similar
kinetics to the WT plasma. A significant delay in the lectin pathway-dependent conversion
of C3 to C3b (and C3dg) was seen in C4-/-as well as in MASP-1/3 deficient plasma. This
delay of C3 activation in MASP-1/3-/- plasma was recently shown to be MASP-1, rather
than MASP-3 dependent (Takahashi, M., et al., J. Immunol. 180:6132-6138 (2008)).
Discussion:
The results described in this Example strongly suggest that MASP-2 functional
activity is essential for the activation of C3 via the lectin pathway both in presence and
absence of C4. Furthermore, C2 and MASP-1 are required for this novel lectin pathway
specific C4-bypass activation route of C3 to work. The comparative analysis of lectin
pathway functional activity in MASP/-as well as C4-/- plasma revealed the existence of a
previously unrecognized C4-independent, but MASPdependent activation route of
complement C3 and showed that C3 can be activated in a lectin pathway-dependent mode in
total absence of C4. While the detailed molecular composition and the sequence of
activation events of this novel MASP-2 dependent C3 convertase remains to be elucidated,
our results imply that this C4-bypass activation route additionally requires the presence of
complement C2 as well as MASP-1. The loss of lectin pathway-mediated C3 cleavage
activity in plasma of mice with combined C4 and MASP-1/3 deficiency may be explained by
a most recently described role of MASP-1 to enhance MASP-2 dependent complement
activation through direct cleavage and activation of MASP-2 (Takahashi, M., et al., J.
Immunol. 180:6132-6138 (2008)). Likewise, MASP-1 may aid MASP-2 functional activity
through its ability to cleave C2 (Moller-Kristensen, et al., Int. Immunol. 19:141-149 (2007)).
Both activities may explain the reduced rate by which MASP-1/3 deficient plasma cleaves
C3 via the lectin activation pathway and why MASP-1 may be required to sustain C3
conversion via the C4-bypass activation route.
The inability of C2/fB-/- plasma to activate C3 via the lectin pathway was shown to
be C2-dependent as the addition of recombinant rat C2 to C2/fB-/- plasma restored the ability
of the reconstituted plasma to activate C3 on Mannan-coated plates.
The finding that C4 deficiency specifically disrupts the classical complement
activation pathway while the lectin pathway retains a physiologically critical level of C3
convertase activity via a MASP-2 dependent C4-bypass activation route calls for a reassessment of the role of the lectin pathway in various disease models, including
experimental S. pneumoniae infection (Brown, J. S., et al., Proc. Natl. Acad. Sci. U. S. A.
99:16969-16974 (2002); Experimental Allergic Encephalomyelitis (Boos, L.A., et al., Glia
49:158-160 (2005); and models of C3 dependent murine liver regeneration (Clark, A., et al.,
Mol. Immunol. 45:3125-3132 (2008)). The latter group demonstrated that C4-deficient mice
can activate C3 in an alternative pathway independent fashion as in vivo inhibition of the
alternative pathway by an antibody-mediated depletion of factor B functional activity did not
effect C3 cleavage-dependent liver regeneration in C4-/- mice (Clark, A., et al. (2008)). This
lectin pathway mediated C4-bypass activation route of C3 may also explain the lack of a
protective phenotype of C4 deficiency in our model of MIRI as well as in a previously
described model of renal allograft rejection (Lin, T., et al., Am. J. Pathol. 168:1241-1248
(2006)). In contrast, our recent results have independently demonstrated a significant
protective phenotype of MASP/-mice in models of renal transplantation (Farrar, C.A., et
al., Mol. Immunol. 46:2832 (2009)).
In summary, the results of this Example support the view that MASP-2 dependent
C4-bypass activation of C3 is a physiologically relevant mechanism that may be important
under conditions where availability of C4 is limiting C3 activation.
EXAMPLE 23
This Example describes activation of C3 by thrombin substrates and C3 deposition on
mannan in WT (+/+), MASP-2 (-/-), F11 (-/-), F11/C4 (-/-) and C4 (-/-) mice.
Rationale:
As described in Example 14, it was determined that thrombin activation can occur
following lectin pathway activation under physiological conditions, and demonstrates the
extent of MASP-2 involvement. C3 plays a central role in the activation of complement
system. C3 activation is required for both classical and alternative complement activation
pathways. An experiment was carried out to determine whether C3 is activated by thrombin
substrates.
Methods:
C3 Activation by thrombin substrates
Activation of C3 was measured in the presence of the following activated forms of
thrombin substrates; human FCXIa, human FVIIa, bovine FXa, human FXa, human activated
protein C, and human thrombin. C3 was incubated with the various thrombin substrates,
then separated under reducing conditions on 10% SDS-polyacrylamide gels. After
electrophoretic transfer using cellulose membrane, the membrane was incubated with
monoclonal biotin-coupled rat anti-mouse C3, detected with a streptavidin-HRP kit and
developed using ECL reagent.
Results:
Activation of C3 involves cleavage of the intact a-chain into the truncated a' chain
and soluble C3a (not shown in FIGURE 30). FIGURE 30 shows the results of a Western
blot analysis on the activation of human C3 by thrombin substrates, wherein the uncleaved
C3 alpha chain, and the activation product a' chain are shown by arrows. As shown in
FIGURE 30, incubation of C3 with the activated forms of human clotting factor XI and
factor X, as well as activated bovine clotting factor X, can cleave C3 in vitro in the absence
of any complement proteases.
C3 deposition on mannan
C3 deposition assays were carried out on serum samples obtained from WT, MASP-2
(-/-), F11(-/-), F11(-/-)/C4(-/-) and C4(-/-). F11 is the gene encoding coagulation factor XI.
To measure C3 activation, microtiter plates were coated with mannan (1 µg/well), then
adding sheep anti-HSA serum (2 µg/ml) in TBS/tween/Ca2+. Plates were blocked with 0.1%
HSA in TBS and washed as above. Plasma samples were diluted in 4 mM barbital, 145 mM
NaCl, 2 mM CaCl2, 1 mM MgCl2, pH 7.4, added to the plates and incubated for 1.5 h at
37°C. After washing, bound C3b was detected using rabbit anti-human C3c (Dako),
followed by alkaline phosphatase-conjugated goat anti-rabbit IgG and pNPP.
Results:
FIGURE 31 shows the results of the C3 deposition assay on serum samples obtained
from WT, MASP-2 (-/-), F11(-/-), F11(-/-)/C4 (-/-) and C4 (-/-). As shown in FIGURE 31,
there is a functional lectin pathway even in the complete absence of C4. As further shown in
FIGURE 31, this novel lectin pathway dependent complement activation requires
coagulation factor XI.
Discussion:
Prior to the results obtained in this experiment, it was believed by those in the art that
the lectin pathway of complement required C4 for activity. Hence, data from C4 knockout
mice (and C4 deficient humans) were interpreted with the assumption that such organisms
were lectin pathway deficient (in addition to classical pathway deficiency). The present
results demonstrate that this notion is false. Thus, conclusions of past studies suggesting that
the lectin pathway was not important in certain disease settings based on the phenotype of C4
deficient animals may be false. The data described in this Example also show that in the
physiological context of whole serum the lectin pathway can activate components of the
coagulation cascade. Thus, it is demonstrated that there is cross-talk between complement
and coagulation involving MASP-2.
EXAMPLE 24
This Example describes methods to assess the effect of an anti-MASP-2 antibody on
lysis of red blood cells from blood samples obtained from Paroxysmal nocturnal
hemoglobinuria (PNH) patients.
Background/Rationale:
Paroxysmal nocturnal hemoglobinuria (PNH), also referred to as MarchiafavaMicheli syndrome, is an acquired, potentially life-threatening disease of the blood,
characterized by complement-induced intravascular hemolytic anemia. The hallmark of
PNH is chronic intravascular hemolysis that is a consequence of unregulated activation of the
alternative pathway of complement. Lindorfer, M.A., et al., Blood 115(11) (2010). Anemia
in PNH is due to destruction of red blood cells in the bloodstream. Symptoms of PNH
include red urine, due to appearance of hemoglobin in the urine, and thrombosis. PNH may
develop on its own, referred to as "primary PNH" or in the context of other bone marrow
disorders such as aplastic anemia, referred to as "secondary PNH". Treatment for PNH
includes blood transfusion for anemia, anticoagulation for thrombosis and the use of the
monoclonal antibody eculizumab (Soliris), which protects blood cells against immune
destruction by inhibiting the complement system (Hillmen P. et al., N. Engl. J. Med.
350(6):552-9 (2004)). However, a significant portion of PNH patients treated with
eculizumab are left with clinically significant immune-mediated hemolytic anemia because
the antibody does not block activation of the alternative pathway of complement.
This Example describes methods to assess the effect of an anti-MASP-2 antibody on
lysis of red blood cells from blood samples obtained from PNH patients (not treated with
Soliris) that are incubated with ABO-matched acidified normal human serum.
Methods:
Reagents:
Erythrocytes from normal donors and from patients suffering from PNH (not treated
with Soliris) are obtained by venipuncture, and prepared as described in Wilcox, L.A., et al.,
Blood 78:820-829 (1991), hereby incorporated herein by reference. Anti-MASP-2 antibodies
with functional blocking activity of the lectin pathway may be generated as described in
Example 10.
Hemolysis Analysis:
The method for determining the effect of anti-MASP-2 antibodies on the ability to
block hemolysis of erythrocytes from PNH patients is carried out using the methods
described in Lindorfer, M.A., et al., Blood 15(11):2283-91 (2010) and Wilcox, L.A., et al.,
Blood 78:820-829 (1991), both references hereby incorporated herein by reference. As
described in Lindorfer et al., erythrocytes from PNH patient samples are centrifuged, the
buffy coat is aspirated and the cells are washed in gelatin veronal buffer (GVB) before each
experiment. The erythrocytes are tested for susceptibility to APC-mediated lysis as follows.
ABO-matched normal human sera are diluted with GVB containing 0.15 mM CaCl2 and 0.5
mM MgCl2 (GVB+2) and acidified to pH 6.4 (acidified NHS, aNHS) and used to reconstitute
the erythrocytes to a hematocrit of 1.6% in 50% aNHS. The mixtures are then incubated at
37ºC, and after 1 hour, the erythrocytes are pelleted by centrifugation. The optical density of
an aliquot of the recovered supernate is measured at 405 nM and used to calculate the percent
lysis. Samples reconstituted in acidified serum-EDTA are processed similarly and used to
define background noncomplement-mediated lysis (typically less than 3%). Complete lysis
(100%) is determined after incubating the erythrocytes in distilled water.
In order to determine the effect of anti-MASP-2 antibodies on hemolysis of PNH
erythrocytes, erythrocytes from PNH patients are incubated in aNHS in the presence of
incremental concentrations of the anti-MASP-2 antibodies, and the presence/amount of
hemolysis is subsequently quantified.
In view of the fact that anti-MASP-2 antibodies have been shown to block subsequent
activation of the alternative complement pathway, it is expected that anti-MASP-2 antibodies
will be effective in blocking alternative pathway-mediated hemolysis of PNH erythrocytes,
and will be useful as a therapeutic to treat patients suffering from PNH.
EXAMPLE 25
This Example describes methods to assess the effect of an anti-MASP-2 blocking
antibody on complement activation by cryoglobulins in blood samples obtained from patients
suffering from cryoglobulinemia.
Background/Rationale:
Cryoglobulinemia is characterized by the presence of cryoglobulins in the serum.
Cryoglobulins are single or mixed immunoglobulins (typically IgM antibodies) that undergo
reversible aggregation at low temperatures. Aggregation leads to classical pathway
complement activation and inflammation in vascular beds, particularly in the periphery.
Clinical presentations of cryoglobulinemia include vasculitis and glomerulonephritis.
Cryoglobulinemia may be classified as follows based on cryoglobulin composition:
Type I cryoglobulinemia, or simple cryoglobulinemia, is the result of a monoclonal
immunoglobulin, usually immunoglobulin M (IgM); Types II and III cryoglobulinemia
(mixed cryoglobulinemia) contain rheumatoid factors (RFs), which are usually IgM in
complexes with the Fc portion of polyclonal IgG.
Conditions associated with cryoglobulinemia include hepatitis C infection,
lymphoproliferative disorders and other autoimmune diseases. Cryoglobulin-containing
immune complexes result in a clinical syndrome of systemic inflammation, possibly due to
their ability to activate complement. While IgG immune complexes normally activate the
classical pathway of complement, IgM containing complexes can also activate complement
via the lectin pathway (Zhang, M., et al., Mol Immunol 44(1-3):103-110 (2007) and Zhang.
M., et al., J. Immunol. 177(7):4727-34 (2006)).
Immunohistochemical studies have further demonstrated the cryoglobulin immune
complexes contain components of the lectin pathway, and biopsies from patients with
cryoglobulinemic glomerulonephritis showed immunohistochemical evidence of lectin
pathway activation in situ (Ohsawa, I., et al., Clin Immunol 101(1):59-66 (2001)). These
results suggest that the lectin pathway may contribute to inflammation and adverse outcomes
in cryoglobulemic diseases.
Methods:
The method for determining the effect of anti-MASP-2 antibodies on the ability to
block the adverse effects of Cryoglobulinemia is carried out using the assay for fluid phase
C3 conversion as described in Ng Y.C. et al., Arthritis and Rheumatism 31(1):99-107 (1988),
hereby incorporated herein by reference. As described in Ng et al., in essential mixed
cryoglobulinemia (EMC), monoclonal rheumatoid factor (mRF), usually IgM, complexes
with polyclonal IgG to form the characteristic cryoprecipitate immune complexes (IC) (type
II cryoglobulin). Immunoglobulins and C3 have been demonstrated in vessel walls in
affected tissues such as skin, nerve and kidney. As described in Ng et al., 125I-labeled mRF
is added to serum (normal human serum and serum obtained from patients suffering from
cryoglobulinemia), incubated at 37ºC, and binding to erythrocytes is measured.
Fluid phase C3 conversion is determined in serum (normal human serum and serum
obtained from patients suffering from cryoglobulinemia) in the presence or absence of the
following IC: BSA-anti BSA, mRF, mRF plus IgG, or cryoglobulins, in the presence or
absence of anti-MASP-2 antibodies. The fixation of C3 and C4 to IC is measured using a
coprecipitation assay with F(ab')2 anti-C3 and F(ab')2 anti-C4.
In view of the fact that anti-MASP-2 antibodies have been shown to block activation
of the lectin pathway it is expected that anti-MASP-2 antibodies will be effective in blocking
complement mediated adverse effects associated with cryoglobulinemia, and will be useful
as a therapeutic to treat patients suffering from cryoglobulinemia.
EXAMPLE 26
This Example describes methods to assess the effect of an anti-MASP-2 antibody on
blood samples obtained from patients with Cold Agglutinin Disease, which manifests as
anemia.
Background/Rationale:
Cold Agglutinin Disease (CAD), is a type of autoimmune hemolytic anemia. Cold
agglutinins antibodies (usually IgM) are activated by cold temperatures and bind to and
aggregate red blood cells. The cold agglutinin antibodies combine with complement and
attack the antigen on the surface of red blood cells. This leads to opsoniation of red blood
cells (hemolysis) which triggers their clearance by the reticuloendothelial system. The
temperature at which the agglutination takes place varies from patient to patient.
CAD manifests as anemia. When the rate of destruction of red blood cell destruction
exceeds the capacity of the bone marrow to produce an adequate number of oxygen-carrying
cells, then anemia occurs. CAD can be caused by an underlying disease or disorder, referred
to as "Secondary CAD", such as an infectious disease (mycoplasma pneumonia, mumps,
mononucleosis), lymphoproliferative disease (lymphoma, chronic lymphocytic leukemia), or
connective tissue disorder. Primary CAD patients are considered to have a low grade
lymphoproliferative bone marrow disorder. Both primary and secondary CAD are acquired
conditions.
Methods:
Reagents:
Erythrocytes from normal donors and from patients suffering from CAD are obtained
by venipuncture. Anti-MASP-2 antibodies with functional blocking activity of the lectin
pathway may be generated as described in Example 10.
The effect of anti-MASP-2 antibodies to block cold aggultinin-mediated activation of
the lectin pathway may be determined as follows. Erythrocytes from blood group I positive
patients are sensitized with cold aggultinins (i.e., IgM antibodies), in the presence or absence
of anti-MASP-2 antibodies. The erythrocytes are then tested for the ability to activate the
lectin pathway by measuring C3 binding.
In view of the fact that anti-MASP-2 antibodies have been shown to block activation
of the lectin pathway, it is expected that anti-MASP-2 antibodies will be effective in
blocking complement mediated adverse effects associated with Cold Agglutinin Disease, and
will be useful as a therapeutic to treat patients suffering from Cold Agglutinin Disease.
EXAMPLE 27
This Example describes methods to assess the effect of an anti-MASP-2 antibody on
lysis of red blood cells in blood samples obtained from mice with atypical hemolytic uremic
syndrome (aHUS).
Background/Rationale:
Atypical hemolytic uremic syndrome (aHUS) is characterized by hemolytic anemia,
thrombocytopenia, and renal failure caused by platelet thrombi in the microcirculation of the
kidney and other organs. aHUS is associated with defective complement regulation and can
be either sporadic or familial. aHUS is associated with mutations in genes coding for
complement activation, including complement factor H, membrane cofactor B and factor I,
and well as complement factor H-related 1 (CFHR1) and complement factor H-related 3
(CFHR3). Zipfel, P.F., et al., PloS Genetics 3(3):e41 (2007). This Example describes
methods to assess the effect of an anti-MASP-2 antibody on lysis of red blood cells from
blood samples obtained from aHUS mice.
Methods:
The effect of anti-MASP-2 antibodies to treat aHUS may be determined in a mouse
model of this disease in which the endogenouse mouse fH gene has been replaced with a
human homologue encoding a mutant form of fH frequently found in aHUS patients. See
Pickering M.C. et al., J. Exp. Med. 204(6):1249-1256 (2007), hereby incorporated herein by
reference. As described in Pickering et al., such mice develop an aHUS like pathology. In
order to assess the effect of an anti-MASP-2 antibody for the treatment of aHUS, anti15 MASP-2 antibodies are administered to the mutant aHUS mice and lysis of red blood cells
obtained from anti-MASP-2 ab treated and untreated controls is compared. In view of the
fact that anti-MASP-2 antibodies have been shown to block activation of the lectin pathway
it is expected that anti-MASP-2 antibodies will be effective in blocking lysis of red blood
cells in mammalian subjects suffering from aHUS.
EXAMPLE 28
This Example describes methods to assess the effect of an anti-MASP-2 antibody for
the treatment of glaucoma.
Rationale/Background:
It has been shown that uncontrolled complement activation contributes to the
progression of degenerative injury to retinal ganglion cells (RGCs), their synapses and axons
in glaucoma. See Tezel G. et al., Invest Ophthalmol Vis Sci 51:5071-5082 (2010). For
example, histopathologic studies of human tissues and in vivo studies using different animal
models have demonstrated that complement components, including C1q and C3, are
synthesized and terminal complement complex is formed in the glaucomatous retina (see
Stasi K. et al., Invest Ophthalmol Vis Sci 47:1024-1029 (2006), Kuehn M.H. et al., Exp Eye
Res 83:620-628 (2006)). As further described in Kuehn M.H. et al., Experimental Eye
Research 87:89-95 (2008), complement synthesis and deposition is induced by retinal I/R
and the disruption of the complement cascade delays RGC degeneration. In this study, mice
carrying a targeted disruption of the complement component C3 were found to exhibit
delayed RGC degeneration after transient retinal I/R when compared to normal animals.
Methods:
The method for determining the effect of anti-MASP-2 antibodies on RGC
degeneration is carried out in an animal model of retinal I/R as described in Kuehn M.H. et
al., Experimental Eye Research 87:89-95 (2008), hereby incorporated herein by reference.
As described in Kuehn et al., retinal ischemia is induced by anesthetizing the animals, then
inserting a 30-gauge needle connected to a reservoir containing phosphate buffered saline
through the cornea into the anterior chamber of the eye. The saline reservoir is then elevated
to yield an intraocular pressure of 104 mmHg, sufficient to completely prevent circulation
through the retinal vasculature. Elevated intraocular ischemia is confirmed by blanching of
the iris and retina and ischemia is maintained for 45 minutes in the left eye only; the right eye
serves as a control and does not receive cannulation. Mice are then euthanized either 1 or 3
weeks after the ischemic insult. Anti-MASP-2 antibodies are administered to the mice either
locally to the eye or systemically to assess the effect of an anti-MASP antibody administered
prior to ischemic insult.
Immunohistochemistry of the eyes is carried out using antibodies against C1q and C3
to detect complement deposition. Optic nerve damage can also be assessed using standard
electron microscopy methods. Quantitation of surviving retinal RGCs is performed using
gamma synuclein labeling.
Results:
As described in Kuehn et al., in normal control mice, transient retinal ischemia results
in degenerative changes of the optic nerve and retinal deposits of C1q and C3 detectable by
immunohistochemistry. In contrast, C3 deficient mice displayed a marked reduction in
axonal degeneration, exhibiting only minor levels of optic nerve damage 1 week after
induction. Based on these results, it is expected that similar results would be observed when
this assay is carried out in a MASP-2 knockout mouse, and when anti-MASP-2 antibodies
are administered to a normal mouse prior to ischemic insult.
EXAMPLE 29
This Example demonstrates that a MASP-2 inhibitor, such as an anti-MASP-2
antibody, is effective for the treatment of radiation exposure and/or for the treatment,
amelioration or prevention of acute radiation syndrome.
Rationale:
Exposure to high doses of ionizing radiation causes mortality by two main
mechanisms: toxicity to the bone marrow and gastrointestinal syndrome. Bone marrow
toxicity results in a drop in all hematologic cells, predisposing the organism to death by
infection and hemorrhage. The gastrointestinal syndrome is more severe and is driven by a
loss of intestinal barrier function due to disintegration of the gut epithelial layer and a loss of
intestinal endocrine function. This leads to sepsis and associated systemic inflammatory
response syndrome which can result in death.
The lectin pathway of complement is an innate immune mechanism that initiates
inflammation in response to tissue injury and exposure to foreign surfaces (i.e., bacteria).
Blockade of this pathway leads to better outcomes in mouse models of ischemic intestinal
tissue injury or septic shock. It is hypothesized that the lectin pathway may trigger excessive
and harmful inflammation in response to radiation-induced tissue injury. Blockade of the
lectin pathway may thus reduce secondary injury and increase survival following acute
radiation exposure.
The objective of the study carried out as described in this Example was to assess the
effect of lectin pathway blockade on survival in a mouse model of radiation injury by
administering anti-murine MASP-2 antibodies.
Methods and Materials:
Materials. The test articles used in this study were (i) a high affinity anti-murine
MASP-2 antibody (mAbM11) and (ii) a high affinity anti-human MASP-2 antibody
(mAbH6) that block the MASP-2 protein component of the lectin complement pathway
which were produced in transfected mammalian cells. Dosing concentrations were 1 mg/kg
of anti-murine MASP-2 antibody (mAbM11), 5mg/kg of anti-human MASP-2 antibody
(mAbH6), or sterile saline. For each dosing session, an adequate volume of fresh dosing
solutions were prepared.
Animals. Young adult male Swiss-Webster mice were obtained from Harlan
Laboratories (Houston, TX). Animals were housed in solid-bottom cages with Alpha-Dri
bedding and provided certified PMI 5002 Rodent Diet (Animal Specialties, Inc., Hubbard
OR) and water ad libitum. Temperature was monitored and the animal holding room
operated with a 12 hour light/12 hour dark light cycle.
Irradiation. After a 2-week acclimation in the facility, mice were irradiated at 6.5
and 7.0 Gy by whole-body exposure in groups of 10 at a dose rate of 0.78 Gy/min using a
Therapax X-RAD 320 system equipped with a 320-kV high stability X-ray generator, metal
ceramic X-ray tube, variable x-ray beam collimator and filter (Precision X-ray Incorporated,
East Haven, CT). Dose levels were selected based on prior studies conducted with the same
strain of mice indicating the LD50/30 was between 6.5 and 7.0 Gy (data not shown).
Drug Formulation and Administration. The appropriate volume of concentrated
stock solutions were diluted with ice cold saline to prepare dosing solutions of 0.2 mg/ml
anti-murine MASP-2 antibody (mAbM11) or 0.5 mg/ml anti-human MASP-2 antibody
(mAbH6) according to protocol. Administration of anti-MASP-2 antibody mAbM11 and
mAbH6 was via IP injection using a 25-gauge needle base on animal weight to deliver 1
mg/kg mAbM11, 5mg/kg mAbH6, or saline vehicle.
Study Design. Mice were randomly assigned to the groups as described in Table 8.
Body weight and temperature were measured and recorded daily. Mice in Groups 7, 11 and
13 were sacrificed at post-irradiation day 7 and blood collected by cardiac puncture under
deep anesthesia. Surviving animals at post-irradiation day 30 were sacrificed in the same
manner and blood collected. Plasma was prepared from collected blood samples according
to protocol and returned to Sponsor for analysis.
TABLE 8: Study Groups
Group
ID N
Irradiation
Level (Gy) Treatment Dose Schedule
1 20 6.5 Vehicle 18 hr prior to irradiation, 2
hr post irradiation, weekly
booster
2 20 6.5 anti-murine
MASP-2 ab
18 hr prior to irradiation
only
Group
ID N
Irradiation
Level (Gy) Treatment Dose Schedule
(mAbM11)
3 20 6.5 anti-murine
MASP-2 ab
(mAbM11)
18 hr prior to irradiation, 2
hr post irradiation, weekly
booster
4 20 6.5 anti-murine
MASP-2 ab
(mAbM11)
2 hr post irradiation,
weekly booster
20 6.5 anti-human
MASP-2 ab
(mAbH6)
18 hr prior to irradiation, 2
hr post irradiation, weekly
booster
6 20 7.0 Vehicle 18 hr prior to irradiation, 2
hr post irradiation, weekly
booster
7 5 7.0 Vehicle 2 hr post irradiation only
8 20 7.0 anti-murine
MASP-2 ab
(mAbM11)
18 hr prior to irradiation
only
9 20 7.0 anti-murine
MASP-2 ab
(mAbM11)
18 hr prior to irradiation, 2
hr post irradiation, weekly
booster
20 7.0 anti-murine
MASP-2 ab
(mAbM11)
2 hr post irradiation,
weekly booster
11 5 7.0 anti-murine
MASP-2 ab
(mAbM11)
2 hr post irradiation only
12 20 7.0 anti-human
MASP-2 ab
(mAbH6)
18 hr prior to irradiation, 2
hr post irradiation, weekly
booster
13 5 None None None
Statistical Analysis. Kaplan-Meier survival curves were generated and used to
compare mean survival time between treatment groups using log-Rank and Wilcoxon
methods. Averages with standard deviations, or means with standard error of the mean are
reported. Statistical comparisons were made using a two-tailed unpaired t-test between
controlled irradiated animals and individual treatment groups.
Results
Kaplan-Meier survival plots for 7.0 and 6.5 Gy exposure groups are provided in
FIGURES 32A and 32B, respectively, and summarized below in Table 9. Overall,
treatment with anti-murine MASP-2 ab (mAbM11) pre-irradiation increased the survival of
irradiated mice compared to vehicle treated irradiated control animals at both 6.5 (20%
increase) and 7.0 Gy (30% increase) exposure levels. At the 6.5 Gy exposure level, postirradiation treatment with anti-murine MASP-2 ab resulted in a modest increase in survival
(15%) compared to vehicle control irradiated animals.
In comparison, all treated animals at the 7.0 Gy exposure level showed an increase in
survival compared to vehicle treated irradiated control animals. The greatest change in
survival occurred in animals receiving mAbH6, with a 45% increase compared to control
animals. Further, at the 7.0 Gy exposure level, mortalities in the mAbH6 treated group first
occurred at post-irradiation day 15 compared to post-irradiation day 8 for vehicle treated
irradiated control animals, an increase of 7 days over control animals. Mean time to
mortality for mice receiving mAbH6 (27.3 ± 1.3 days) was significantly increased (p =
0.0087) compared to control animals (20.7 ± 2.0 days) at the 7.0 Gy exposure level.
The percent change in body weight compared to pre-irradiation day (day -1) was
recorded throughout the study. A transient weight loss occurred in all irradiated animals,
with no evidence of differential changes due to mAbM11 or mAbH6 treatment compared to
controls (data not shown). At study termination, all surviving animals showed an increase in
body weight from starting (day -1) body weight.
TABLE 9: Survival rates of test animals exposed to radiation
Test Group Exposure
Level
Survival (%) Time to Death
(Mean ± SEM,
Day)
First/Last Death
(Day)
Control Irradiation 6.5 Gy 65 % 24.0 ± 2.0 9/16
mAbM11 preexposure
6.5 Gy 85 % 27.7 ± 1.5 13/17
mAbM11 pre + 6.5 Gy 65 % 24.0 ± 2.0 9/15
Test Group Exposure
Level
Survival (%) Time to Death
(Mean ± SEM,
Day)
First/Last Death
(Day)
post-exposure
mAbM11 postexposure
6.5 Gy 80 % 26.3 ± 1.9 9/13
mAbH6 pre+postexposure
6.5 Gy 65 % 24.6 ± 1.9 9/19
Control irraditation 7.0 Gy 35 % 20.7 ± 2.0 8/17
mAbM11 preexposure
7.0 Gy 65 % 23.0 ± 2.3 7/13
mAbM11 pre +
post-exposure
7.0 Gy 55 % 21.6 ± 2.2 7/16
mAbM11 postexposure
7.0 Gy 70 % 24.3 ± 2.1 9/14
mAbH6 pre+postexposure
7.0 Gy 80 % 27.3 ± 1.3* 15/20
*p = 0.0087 by two-tailed unpaired t-test between controlled irradiated animals and
treatment group at the same irradiation exposure level.
Discussion
Acute radiation syndrome consists of three defined subsyndromes: hematopoietic,
gastrointestinal, and cerebrovascular. The syndrome observed depends on the radiation dose,
with the hematopoietic effects observed in humans with significant partial or whole-body
radiation exposures exceeding 1 Gy. The hematopoietic syndrome is characterized by severe
depression of bone-marrow function leading to pancytopenia with changes in blood counts,
red and white blood cells, and platelets occurring concomitant with damage to the immune
system. As nadir occurs, with few neutrophils and platelets present in peripheral blood,
neutropenia, fever, complications of sepsis and uncontrollable hemorrhage lead to death.
In the present study, administration of mAbH6 was found to increase survivability of
whole-body x-ray irradiation in Swiss-Webster male mice irradiated at 7.0 Gy. Notably, at
the 7.0 Gy exposure level, 80% of the animals receiving mAbH6 survived to 30 days
compared to 35% of vehicle treated control irradiated animals. Importantly, the first day of
death in this treated group did not occur until post-irradiation day 15, a 7-day increase over
that observed in vehicle treated control irradiated animals. Curiously, at the lower X-ray
exposure (6.5 Gy), administration of mAbH6 did not appear to impact survivability or delay
in mortality compared to vehicle treated control irradiated animals. There could be multiple
reasons for this difference in response between exposure levels, although verification of any
hypothesis may require additional studies, including interim sample collection for
microbiological culture and hematological parameters. One explanation may simply be that
the number of animals assigned to groups may have precluded seeing any subtle treatmentrelated differences. For example, with groups sizes of n=20, the difference in survival
between 65% (mAbH6 at 6.5 Gy exposure) and 80% (mAbH6 at 7.0 Gy exposure) is 3
animals. On the other hand, the difference between 35% (vehicle control at 7.0 Gy exposure)
and 80% (mAbH6 at 7.0 Gy exposure) is 9 animals, and provides sound evidence of a
treatment-related difference.
These results demonstrate that anti-MASP-2 antibodies are effective in treating a
mammalian subject at risk for, or suffering from the detrimental effects of acute radiation
syndrome.
EXAMPLE 30
This Example demonstrates that MASP-2 deficient mice are protected from Neisseria
meningitidis induced mortality after infection with either N. meningitidis serogroup A or
Neisseria meningitidis serogroup B.
Methods:
MASP-2 knockout mice (MASP-2 KO mice) were generated as described in Example
1. 10-week-old MASP-2 KO mice (n=10) and wild-type (WT) C57/BL6 mice (n=10) were
inoculated by intraperitoneal (i.p.) injection with a dosage of 2.6 x 107 CFU of Neisseria
meningitidis serogroup A Z2491 in a volume of 100 µl. The infective dose was administered
to mice in conjunction with iron dextran at a final concentration of 400 mg/kg. Survival of
the mice after infection was monitored over a 72-hour time period.
In a separate experiment, 10-week-old MASP-2 KO mice (n=10) and wild-type
C57/BL6 mice (n=10) were inoculated by i.p. injection with a dosage of 6 x 106 CFU of
Neisseria meningitidis serogroup B strain MC58 in a volume of 100 µl. The infective dose
was administered to mice in conjunction with iron dextran at a final dose of 400 mg/kg.
Survival of the mice after infection was monitored over a 72-hour time period. An illness
score was also determined for the WT and MASP-2 KO mice during the 72-hour time period
after infection, based on the illness scoring parameters described below in TABLE 10, which
is based on the scheme of Fransen et al. (2010) with slight modifications.
TABLE 10: Illness Scoring associated with clinical signs in infected mice
Signs Score
Normal 0
Slightly ruffled fur 1
Ruffled fur, slow and sticky eyes 2
Ruffled fur, lethargic and eyes shut 3
Very sick and no movement after
stimulation
4
Dead 5
Blood samples were taken from the mice at hourly intervals after infection and
analyzed to determine the serum level (log cfu/mL) of N. meningitidis in order to verify
infection and determine the rate of clearance of the bacteria from the serum.
Results:
FIGURE 33 is a Kaplan-Meyer plot graphically illustrating the percent survival of
MASP-2 KO and WT mice after administration of an infective dose of 2.6 x 107 cfu of N.
meningitidis serogroup A Z2491. As shown in FIGURE 33, 100% of the MASP-2 KO mice
survived throughout the 72-hour period after infection. In contrast, only 80% of the WT
mice (p=0.012) were still alive 24 hours after infection, and only 50% of the WT mice were
still alive at 72 hours after infection. These results demonstrate that MASPdeficient mice
are protected from N. meningitidis serogroup A Z2491-induced mortality.
FIGURE 34 is a Kaplan-Meyer plot graphically illustrating the percent survival of
MASP-2 KO and WT mice after administration of an infective dose of 6 x 106 20 cfu of N.
meningitidis serogroup B strain MC58. As shown in FIGURE 34, 90% of the MASP-2 KO
mice survived throughout the 72-hour period after infection. In contrast, only 20% of the
WT mice (p=0.0022) were still alive 24 hours after infection. These results demonstrate that
MASPdeficient mice are protected from N. meningitidis serogroup B strain MC58-
induced mortality.
FIGURE 35 graphically illustrates the log cfu/mL of N. meningitidis serogroup B
strain MC58 recovered at different time points in blood samples taken from the MASP-2 KO
and WT mice after i.p. infection with 6x106 cfu of N. meningitidis serogroup B strain MC58
(n=3 at different time points for both groups of mice). The results are expressed as
Means±SEM. As shown in FIGURE 35, in WT mice the level of N. meningitidis in the
blood reached a peak of about 6.0 log cfu/mL at 24 hours after infection and dropped to
about 4.0 log cfu/mL by 36 hours after infection. In contrast, in the MASP-2 KO mice, the
level of N. meningitidis reached a peak of about 4.0 log cfu/mL at 12 hours after infection
and dropped to about 1.0 log cfu/mL by 36 hours after infection (the symbol "*" indicates
p<0.05; the symbol "**" indicates p=0.0043). These results demonstrate that although the
MASP-2 KO mice were infected with the same dose of N. meningitidis serogroup B strain
MC58 as the WT mice, the MASP-2 KO mice have enhanced clearance of bacteraemia as
compared to WT.
FIGURE 36 graphically illustrates the average illness score of MASP-2 KO and WT
mice at 3, 6, 12 and 24 hours after infection with 6x106 cfu of N. meningitidis serogroup B
strain MC58. As shown in FIGURE 36, the MASPdeficient mice showed high resistance
to the infection, with much lower illness scores at 6 hours (symbol "*" indicates p=0.0411),
12 hours (symbol "**" indicates p=0.0049) and 24 hours (symbol "***" indicates p=0.0049)
after infection, as compared to WT mice. The results in FIGURE 36 are expressed as
means±SEM.
In summary, the results in this Example demonstrate that MASPdeficient mice are
protected from Neisseria meningitides-induced mortality after infection with either N.
meningitidis serogroup A or N. meningitidis serogroup B.
EXAMPLE 31
This Example demonstrates that the administration of anti-MASP-2 antibody after
infection with N. meningitidis increases the survival of mice infected with N. meningitidis.
Background/Rationale:
As described in Example 10, rat MASP-2 protein was utilized to pan a Fab phage
display library, from which Fab2 #11 was identified as a functionally active antibody. Fulllength antibodies of the rat IgG2c and mouse IgG2a isotypes were generated from Fab2 #11.
The full-length anti-MASP-2 antibody of the mouse IgG2a isotype was characterized for
pharmacodynamic parameters (as described in Example 19).
In this Example, the mouse anti-MASP-2 full-length antibody derived from Fab2 #11
was analyzed in the mouse model of N. meningitidis infection.
Methods:
The mouse IgG2a full-length anti-MASP-2 antibody isotype derived from Fab2 #11,
generated as described above, was tested in the mouse model of N. meningitidis infection as
follows.
Administration of mouse-anti-MASP-2 Monoclonal antibodies (MoAb) after
infection
9-week-old C57/BL6 Charles River mice were treated with inhibitory mouse antiMASP-2 antibody (1.0 mg/kg) (n=12) or control isotype antibody (n=10) at 3 hours after i.p.
injection with a high dose (4x106 cfu) of N. meningitidis serogroup B strain MC58.
Results:
FIGURE 37 is a Kaplan-Meyer plot graphically illustrating the percent survival of
mice after administration of an infective dose of 4x106 20 cfu of N. meningitidis serogroup B
strain MC58, followed by administration 3 hours post-infection of either inhibitory antiMASP-2 antibody (1.0 mg/kg) or control isotype antibody. As shown in FIGURE 37, 90%
of the mice treated with anti-MASP-2 antibody survived throughout the 72-hour period after
infection. In contrast, only 50% of the mice treated with isotype control antibody survived
throughout the 72-hour period after infection. The symbol "*" indicates p=0.0301, as
determined by comparison of the two survival curves.
These results demonstrate that administration of anti-MASP-2 antibody is effective to
treat and improve survival in subjects infected with N. meningitidis.
As demonstrated herein, the use of anti-MASP-2 antibody in the treatment of a
subject infected with N. meningitidis is effective when administered within 3 hours post-
infection, and is expected to be effective within 24 hours to 48 hours after infection.
Meningococcal disease (either meningococcemia or meningitis) is a medical emergency, and
therapy will typically be initiated immediately if meningococcal disease is suspected (i.e.,
before N. meningitidis is positively identified as the etiological agent).
In view of the results in the MASP-2 KO mouse demonstrated in EXAMPLE 30, it is
believed that administration of anti-MASP-2 antibody prior to infection with N. meningitidis
would also be effective to prevent or ameliorate the severity of infection.
EXAMPLE 32
This Example demonstrates that administration of anti-MASP-2 antibody is effective
to treat N. meningitidis infection in human serum.
Rationale:
Patients with decreased serum levels of functional MBL display increased
susceptibility to recurrent bacterial and fungal infections (Kilpatrick et al., Biochim Biophys
Acta 1572:401-413 (2002)). It is known that N. meningitidis is recognized by MBL, and it
has been shown that MBL-deficient sera do not lyse Neisseria.
In view of the results described in Examples 30 and 31, a series of experiments were
carried out to determine the efficacy of administration of anti-MASP-2 antibody to treat N.
meningitidis infection in complement-deficient and control human sera. Experiments were
carried out in a high concentration of serum (20%) in order to preserve the complement
pathway.
Methods:
1. Serum bactericidal activity in various complement-deficient human sera and in
human sera treated with human anti-MASP-2 antibody
The following complement-deficient human sera and control human sera were used
in this experiment:
TABLE 11: Human sera samples tested (as shown in FIGURE 38)
Sample Serum type
A Normal human sera (NHS) + human anti-MASP-2 Ab
B NHS + isotype control Ab
C MBL -/- human serum
D NHS
E Heat-Inactivated (HI) NHS
A recombinant antibody against human MASP-2 was isolated from a Combinatorial
Antibody Library (Knappik, A., et al., J. Mol. Biol. 296:57-86 (2000)), using recombinant
human MASP-2A as an antigen (Chen, C.B. and Wallis, J. Biol. Chem. 276:25894-25902
(2001)). An anti-human scFv fragment that potently inhibited lectin pathway-mediated
activation of C4 and C3 in human plasma (IC50~20 nM) was identified and converted to a
full-length human IgG4 antibody.
N. meningitidis serogroup B-MC58 was incubated with the different sera show in
TABLE 11, each at a serum concentration of 20%, with or without the addition of inhibitory
human anti-MASP-2 antibody (3 µg in 100 µl total volume) at 37°C with shaking. Samples
were taken at the following time points: 0-, 30-, 60- and 90-minute intervals, plated out and
then viable counts were determined. Heat-inactivated human serum was used as a negative
control.
Results:
FIGURE 38 graphically illustrates the log cfu/mL of viable counts of N. meningitidis
serogroup B-MC58 recovered at different time points in the human sera samples shown in
TABLE 11. TABLE 12 provides the Student’s t-test results for FIGURE 38.
TABLE 12: Student's t-test Results for FIGURE 38 (time point 60 minutes)
Mean Diff. (Log) Significant?
P<0.05?
P value summary
A vs B -0.3678 Yes ***(0.0002)
A vs C -1.1053 Yes ***(p<0.0001)
A vs D -0.2111 Yes **(0.0012)
C vs D 1.9 Yes ***(p<0.0001)
As shown in FIGURE 38 and TABLE 12, complement-dependent killing of N.
meningitidis in human 20% serum was significantly enhanced by the addition of the human
anti-MASP-2 inhibitory antibody.
2. Complement-dependent killing of N. meningitidis in 20% (v/v) mouse sera
deficient of MASP-2.
The following complement-deficient mouse sera and control mouse sera were used in
this experiment:
TABLE 13: Mouse sera samples tested (as shown in FIGURE 39)
Sample Serum Type
A WT
B MASP-2 -/-
C MBL A/C -/-
D WT heat-inactivated (HIS)
N. meningitidis serogroup B-MC58 was incubated with different complement10 deficient mouse sera, each at a serum concentration of 20%, at 37°C with shaking. Samples
were taken at the following time points: 0-, 15-, 30-, 60-, 90- and 120-minute intervals,
plated out and then viable counts were determined. Heat-inactivated human serum was used
as a negative control.
Results:
FIGURE 39 graphically illustrates the log cfu/mL of viable counts of N. meningitidis
serogroup B-MC58 recovered at different time points in the mouse sera samples shown in
TABLE 13. As shown in FIGURE 39, the MASP-2 -/- mouse sera have a higher level of
bactericidal activity for N. meningitidis than WT mouse sera. The symbol "**" indicates
p=0.0058, the symbol "***" indicates p=0.001. TABLE 14 provides the Student's t-test
results for FIGURE 39.
TABLE 14: Student's t-test Results for FIGURE 39
Comparison Time point Mean Diff.
(LOG)
Significant?
(p<0.05)?
P value summary
A vs. B 60 min. 0.39 yes ** (0.0058)
A vs. B 90 min. 0.6741 yes *** (0.001)
In summary, the results in this Example demonstrate that MASP-2 -/- sera has a
higher level of bactericidal activity for N. meningitidis than WT sera.
EXAMPLE 33
This Example demonstrates the inhibitory effect of MASP-2 deficiency on lysis of
red blood cells from blood samples obtained from a mouse model of paroxysmal nocturnal
hemoglobinuria (PNH).
Background/Rationale:
Paroxysmal nocturnal hemoglobinuria (PNH), also referred to as MarchiafavaMicheli syndrome, is an acquired, potentially life-threatening disease of the blood,
characterized by complement-induced intravascular hemolytic anemia. The hallmark of
PNH is the chronic complement-mediated intravascular hemolysis that is a consequence of
unregulated activation of the alternative pathway of complement due to the absence of the
complement regulators CD55 and CD59 on PNH erythrocytes, with subsequent
hemoglobinuria and anemia. Lindorfer, M.A., et al., Blood 115(11) (2010), Risitano, A.M,
Mini-Reviews in Medicinal Chemistry, 11:528-535 (2011). Anemia in PNH is due to
destruction of red blood cells in the bloodstream. Symptoms of PNH include red urine, due
to appearance of hemoglobin in the urine, back pain, fatigue, shortness of breath and
thrombosis. PNH may develop on its own, referred to as "primary PNH" or in the context of
other bone marrow disorders such as aplastic anemia, referred to as "secondary PNH".
Treatment for PNH includes blood transfusion for anemia, anticoagulation for thrombosis
and the use of the monoclonal antibody eculizumab (Soliris®), which protects blood cells
against immune destruction by inhibiting the complement system (Hillmen P. et al., N. Engl.
J. Med. 350(6):552-9 (2004)). Eculizumab (Soliris®) is a humanized monoclonal antibody
that targets the complement component C5, blocking its cleavage by C5 convertases, thereby
preventing the production of C5a and the assembly of the MAC. Treatment of PNH patients
with eculizumab has resulted in a reduction of intravascular hemolysis, as measured by
lactate dehydrogenase (LDH), leading to hemoglobin stabilization and transfusion
independence in about half of the patients (Hillmen P, et al., Mini-Reviews in Medicinal
Chemistry, vol 11(6) (2011)). While nearly all patients undergoing therapy with eculizumab
achieve normal or almost normal LDH levels (due to control of intravascular hemolysis),
only about one third of the patients reach a hemoglobin value above 11gr/dL, and the
remaining patients on eculizumab continue to exhibit moderate to severe (i.e.,transfusiondependent) anemia, in about equal proportions (Risitano A.M. et al., Blood 113:4094-100
(2009)). As described in Risitano et al., Mini-Reviews in Medicinal Chemistry 11:528-535
(2011), it was demonstrated that PNH patients on eculizumab contained C3 fragments bound
to a substantial portion of their PNH erythrocytes (while untreated patients did not), leading
to the conclusion that membrane-bound C3 fragments work as opsonins on PNH
erythrocytes, resulting in their entrapment in the reticuloendothelial cells through specific C3
receptors and subsequent extravascular hemolysis. Therefore, therapeutic strategies in
addition to the use of eculizumab are needed for those patients developing C3 fragmentmediated extravascular hemolysis because they continue to require red cell transfusions.
This Example describes methods to assess the effect of MASP deficient serum and
serum treated with MASP-2 inhibitory agent on lysis of red blood cells from blood samples
obtained from a mouse model of PNH and demonstrates the efficacy of MASP-2 inhibition
to treat subjects suffering from PNH, and also supports the use of inhibitors of MASP-2 to
ameliorate the effects of C3 fragment-mediated extravascular hemolysis in PNH subjects
undergoing therapy with a C5 inhibitor such as eculizumab.
Methods:
PNH animal model:
Blood samples were obtained from gene-targeted mice with deficiencies of Crry and
C3 (Crry/C3-/-) and CD55/CD59-deficient mice. These mice are missing the respective
surface complement regulators and their erythrocytes are, therefore, susceptible to
spontaneous complement autolysis as are PNH human blood cells.
In order to sensitize these erythrocytes even more, these cells were used with and
without coating by mannan and then tested for hemolysis in WT C56/BL6 plasma, MBL null
plasma, MASP-2 -/- plasma, human NHS, human MBL -/- plasma, and NHS treated with
human anti-MASP-2 antibody.
1. Hemolysis assay of Crry/C3 and CD55/CD59 double-deficient murine erythrocytes in
MASPdeficient/depleted sera and controls
Day 1. Preparation of murine RBC (± mannan coating)
Materials included: fresh mouse blood, BBS/Mg2+/Ca2+ 5 (4.4 mM barbituric acid, 1.8
mM sodium barbitone, 145 mM NaCl, pH7.4, 5mM Mg2+, 5mM Ca2+), chromium chloride,
CrCl3·6H20 (0.5mg/mL in BBS/Mg2+/Ca2+) and mannan, 100 µg/mL in BBS /Mg2+/Ca2+.
Whole blood (2mL) was spun down for 1-2 min at 2000xg in a refrigerated centrifuge
at 4˚C. The plasma and buffy coat were aspirated off. The sample was then washed three
times by re-suspending the RBC pellet in 2 mL ice-cold BBS/gelatin/Mg2+/Ca2+ and
repeating centrifugation step. After the third wash, the pellet was re-suspended in 4mL
BBS/Mg2+/Ca2+. A 2 mL aliquot of the RBC was set aside as an uncoated control. To the
remaining 2 mL, 2 mL CrCl3 and 2 mL mannan were added and the sample was incubated
with gentle mixing at room temperature for 5 minutes. The reaction was terminated by
adding 7.5mL BBS/gelatin/Mg2+/Ca2+. The sample was spun down as above, re-suspended
in 2 mL BBS/gelatin/Mg2+/Ca2+ and washed a further two times as above, then stored at
4˚C.
Day 2. Hemolysis assay
Materials included BBS/gelatin/Mg2+/Ca2+ (as above), test sera, 96-well round20 bottomed and flat-bottomed plates and a spectrophotometer that reads 96-well plates at 410-
414 nm.
The concentration of the RBC was first determined and the cells were adjusted to
109
/mL, and stored at this concentration. Before use, the assay buffer was diluted to 108
/mL,
and then 100ul per well was used. Hemolysis was measured at 410-414 nm (allowing for
greater sensitivity then 541nm). Dilutions of test sera were prepared in ice-cold
BBS/gelatin/Mg2+/Ca2+. 100µl of each serum dilution was pipetted into round-bottomed
plate (see plate layout). 100µl of appropriately diluted RBC preparation was added (i.e., 108
/mL) (see plate layout), incubated at 37°C for about 1 hour, and observed for lysis. (The
plates may be photographed at this point.) The plate was then spun down at maximum speed
for 5 minutes. 100µl was aspirated of the fluid-phase, transferred to flat-bottom plates, and
the OD was recorded at 410-414 nm. The RBC pellets were retained (these can be
subsequently lysed with water to obtain an inverse result).
Experiment #1:
Fresh blood was obtained from CD55/CD59 double-deficient mice and blood of
Crry/C3 double-deficient mice and erythrocytes were prepared as described in detail in the
above protocol. The cells were split and half of the cells were coated with mannan and the
other half were left untreated, adjusting the final concentration to 1x 108 per mL, of which
100 µl was used in the hemolysis assay, which was carried out as described above.
Results of Experiment #1: The lectin pathway is involved in erythrocyte lysis in
the PNH animal model
In an initial experiment, it was determined that non-coated WT mouse erythrocytes
were not lysed in any mouse serum. It was further determined that mannan-coated Crry-/-
mouse erythrocytes were slowly lysed (more than 3 hours at 37 degrees) in WT mouse
serum, but they were not lysed in MBL null serum. (Data not shown).
It was determined that mannan-coated Crry-/- mouse erythrocytes were rapidly lysed
in human serum but not in heat-inactivated NHS. Importantly, mannan-coated Crry-/- mouse
erythrocytes were lysed in NHS diluted down to 1/640 (i.e., 1/40, 1/80, 1/160, 1/320 and
1/640 dilutions all lysed). (Data not shown). In this dilution, the alternative pathway does
not work (AP functional activity is significantly reduced below 8% serum concentration).
Conclusions from Experiment #1
Mannan-coated Crry-/- mouse erythrocytes are very well lysed in highly diluted
human serum with MBL but not in that without MBL. The efficient lysis in every serum
concentration tested implies that the alternative pathway is not involved or needed for this
lysis. The inability of MBL-deficient mouse serum and human serum to lyse the mannan25 coated Crry-/- mouse erythrocytes indicates that the classical pathway also has nothing to do
with the lysis observed. As lectin pathway recognition molecules are required (i.e., MBL),
this lysis is mediated by the lectin pathway.
Experiment #2:
Fresh blood was obtained from the Crry/C3 and CD55/CD59 double-deficient mice
and mannan-coated Crry-/- mouse erythrocytes were analyzed in the haemolysis assay as
described above in the presence of the following human serum: MBL null; WT; NHS
pretreated with human anti-MASP-2 antibody; and heat-inactivated NHS as a control.
Results of Experiment #2: MASP-2 inhibitors prevent erythrocyte lysis in the PNH
animal model
With the Mannan-coated Crry-/- mouse erythrocytes, NHS was incubated in the
dilutions diluted down to 1/640 (i.e., 1/40, 1/80, 1/160, 1/320 and 1/640), human MBL-/-
serum, NHS pretreated with anti-MASP-2 mAb, and heat-inactivated NHS as a control.
The ELISA microtiter plate was spun down and the non-lysed erythrocytes were
collected on the bottom of the round-well plate. The supernatant of each well was collected
and the amount of hemoglobin released from the lysed erythrocytes was measured by reading
the OD415 nm in an ELISA reader.
In the control heat-inactivated NHS (negative control), as expected, no lysis was
observed. MBL-/- human serum lysed mannan-coated mouse erythrocytes at 1/8 and 1/16
dilutions. Anti-MASPantibody-pretreated NHS lysed mannan-coated mouse erythrocytes
at 1/8 and 1/16 dilutions while WT human serum lysed mannan-coated mouse erythrocytes
down to dilutions of 1/32.
FIGURE 40 graphically illustrates hemolysis (as measured by hemoglobin release of
lysed mouse erythrocytes (Cryy/C3-/-) into the supernatant measured by photometry) of
mannan-coated murine erythrocytes by human serum over a range of serum concentrations in
serum from heat-inactivated (HI) NHS, MBL-/-, NHS pretreated with anti-MASP-2
antibody, and NHS control.
From the results shown in FIGURE 40, it is demonstrated that MASP-2 inhibition
with anti-MASP-2 antibody significantly shifted the CH50 and inhibited complementmediated lysis of sensitized erythrocytes with deficient protection from autologous
complement activation.
Experiment #3
Fresh blood obtained from the Crry/C3 and CD55/CD59 double-deficient mice in
non-coated Crry-/- mouse erythrocytes was analyzed in the hemolysis assay as described
above in the presence of the following serum: MBL -/-; WT sera; NHS pretreated with
human anti-MASP-2 antibody and heat-inactivated NHS as a control.
Results:
FIGURE 41 graphically illustrates hemolysis (as measured by hemoglobin release of
lysed WT mouse erythrocytes into the supernatant measured by photometry) of non-coated
murine erythrocytes by human serum over a range of serum concentrations in serum from
heat inactivated (HI) NHS, MBL-/-, NHS pretreated with anti-MASP-2 antibody, and NHS
control. As shown in FIGURE 41, it is demonstrated that inhibiting MASP-2 inhibits
complement-mediated lysis of non-sensitized WT mouse erythrocytes.
FIGURE 42 graphically illustrates hemolysis (as measured by hemoglobin release of
lysed mouse erythrocytes (CD55/59 -/-) into the supernatant measured by photometry) of
non-coated murine erythrocytes by human serum over a range of serum concentration in
serum from heat-inactivated (HI) NHS, MBL-/-, NHS pretreated with anti-MASP-2
antibody, and NHS control.
TABLE 12: CH50 values expressed as serum concentrations
Serum WT CD55/59 -/-
Heat-inactivated NHS No lysis No lysis
MBL AO/XX donor
(MBL deficient)
7.2% 2.1%
NHS + anti-MASP-2
antibody
.4% 1.5%
NHS 3.1% 0.73%
Note: “CH50” is the point at which complement mediated hemolysis reaches 50%.
In summary, the results in this Example demonstrate that inhibiting MASP-2 inhibits
complement-mediated lysis of sensitized and non-sensitized erythrocytes with deficient
protection from autologous complement activation. Therefore, MASP-2 inhibitors may be
used to treat subjects suffering from PNH, and may also be used to ameliorate (i.e., inhibit,
prevent or reduce the severity of) extravascular hemolysis in PNH patients undergoing
treatment with a C5 inhibitor such as eculizumab (Soliris®).
EXAMPLE 34
This Example describes a follow on study to the study described above in Example
29, providing further evidence confirming that a MASP-2 inhibitor, such as a MASP-2
antibody, is effective for the treatment of radiation exposure and/or for the treatment,
amelioration or prevention of acute radiation syndrome.
Rationale: In the initial study described in Example 29, it was demonstrated that preirradiation treatment with an anti-MASP-2 antibody in mice increased the survival of
irradiated mice as compared to vehicle treated irradiated control animals at both 6.5 Gy and
7.0 Gy exposure levels. It was further demonstrated in Example 29 that at the 6.5 Gy
exposure level, post-irradiation treatment with anti-MASP-2 antibody resulted in a modest
increase in survival as compared to vehicle control irradiated animals. This Example
describes a second radiation study that was carried out to confirm the results of the first
study.
Methods:
Design of Study A:
Swiss Webster mice (n=50) were exposed to ionizing radiation (8.0 Gy). The effect of antiMASP-2 antibody therapy (mAbH6 5mg/kg), administered 18 hours before and 2 hours after
radiation exposure, and weekly thereafter, on mortality was assessed.
Results of Study A:
As shown in FIGURE 43, it was determined that administration of the anti-MASP-2 antibody
mAbH6 increased survival in mice exposed to 8.0 Gy, with an adjusted median survival rate
increased from 4 to 6 days as compared to mice that received vehicle control, and a mortality
reduced by 12% when compared to mice that received vehicle control (log-rank test,
p=0.040).
Design of Study B:
Swiss Webster mice (n=50) were exposed to ionizing radiation (8.0 Gy) in the following
groups (I: vehicle) saline control; (II: low) anti-MASP-2 antibody mAbH6 (5 mg/kg)
administered 18 hours before irradiation and 2 hours after irradiation; (III: high) mAbH6 (10
mg/kg) administered 18 hours before irradiation and 2 hours post irradiation; and (IV:high
post) mAbH6 (10mg/kg) administered 2 hours post irradiation only.
Results of Study B:
Administration of anti-MASP-2 antibody pre- and post-irradiation adjusted the mean survival
from 4 to 5 days in comparison to animals that received vehicle control. Mortality in the
anti-MASP-2 antibody-treated mice was reduced by 6-12% in comparison to vehicle control
mice. It is further noted that no significant detrimental treatment effects were observed (data
not shown).
In summary, the results shown in this Example are consistent with the results shown
in Example 29 and further demonstrate that anti-MASP-2 antibodies are effective in treating
a mammalian subject at risk for, or suffering from the detrimental effects of acute radiation
syndrome.
EXAMPLE 35
This study investigates the effect of MASPdeficiency in a mouse model of LPS
(lipopolysaccharide)-induced thrombosis.
Rationale:
Hemolytic uremic syndrome (HUS), which is caused by Shiga toxin-producing E.
coli infection, is the leading cause of acute renal failure in children. In this Example, a
Schwartzman model of LPS-induced thrombosis (microvascular coagulation) was carried out
in MASP/- (KO) mice to determine whether MASP-2 inhibition is effective to inhibit or
prevent the formation of intravascular thrombi.
Methods:
MASP/- (n=9) and WT (n=10) mice were analyzed in a Schwarztman model of
LPS-induced thrombosis (microvascular coagulation). Mice were administered Serratia LPS
and thrombus formation was monitored over time. A comparison of the incidence of
microthromi and LPS-induced microvascular coagulation was carried out.
Results:
Notably, all MASP-2 -/- mice tested (9/9) did not form intravascular thrombi after
Serratia LPS administration. In contrast, microthrombi were detected in 7 of 10 of the WT
mice tested in parallel (p=0.0031, Fischer’s exact). As shown in FIGURE 44, the time to
onset of microvascular occlusion following LPS infection was measured in MASP/- and
WT mice, showing the percentage of WT mice with thrombus formation measured over 60
minutes, with thrombus formation detected as early as about 15 minutes. Up to 80% of the
WT mice demonstrated thrombus formation at 60 minutes. In contrast, as shown in FIGURE
44, none of the MASP-2 -/- had thrombus formation at 60 minutes (log rank: p=0.0005).
These results demonstrate that MASP-2 inhibition is protective against the
development of intravascular thrombi in an HUS model.
EXAMPLE 36
This Example describes the effect of anti-MASP-2 antibodies in a mouse model of
HUS using intraperitoneal co-injection of purified Shiga toxin 2 (STX2) plus LPS.
Background:
A mouse model of HUS was developed using intraperitoneal co-injection of purified
Shiga toxin 2 (STX2) plus LPS. Biochemical and microarray analysis of mouse kidneys
revealed the STX2 plus LPS challenge to be distinct from the effects of either agent alone.
Blood and serum analysis of these mice showed neutrophilia, thrombocytopenia, red cell
hemolysis, and increased serum creatinine and blood urea nitrogen. In addition, histologic
analysis and electron microscopy of mouse kidneys demonstrated glomerular fibrin
deposition, red cell congestion, microthrombi formation, and glomerular ultrastructural
changes. It was established that this model of HUS induces all clinical symptoms of human
HUS pathology in C57BL/6 mice including thrombocytopenia, hemolytic anemia, and renal
failure that define the human disease. (J. Immunol 187(1):172-80 (2011))
Methods:
C57BL/6 female mice that weighed between 18 to 20 g were purchased from Charles
River Laboratories and divided in to 2 groups (5 mice in each group). One group of mice
was pretreated by intraperitoneal (i.p.) injection with the recombinant anti-MASP-2 antibody
mAbM11 (100 µg per mouse; corresponding to a final concentration of 5 mg/kg body
weight) diluted in a total volume of 150 µl saline. The control group received saline without
any antibody. Six hours after i.p injection of anti-MASP-2 antibody mAbM11, all mice
received a combined i.p. injection of a sublethal dose (3 µg/animal; corresponding to 150
µg/kg body weight) of LPS of Serratia marcescens (L6136; Sigma-Aldrich, St. Louis, MO)
and a dose of 4.5 ng/animal (corresponding to 225 ng/kg) of STX2 (two times the LD50
dose) in a total volume of 150 µl. Saline injection was used for control.
Survival of the mice was monitored every 6 hours after dosing. Mice were culled as
soon as they reached the lethargic stage of HUS pathology. After 36 hours, all mice were
culled and both kidneys were removed for immunohistochemistry and scanning electron
microscopy. Blood samples were taken at the end of the experiment by cardiac puncture.
Serum was separated and kept frozen at -80ºC for measuring BUN and serum Creatinine
levels in both treated and control groups.
Immunohistochemistry
One-third of each mouse kidney was fixed in 4% paraformaldehyde for 24 h,
processed, and embedded in paraffin. Three-micron-thick sections were cut and placed onto
charged slides for subsequent staining with H & E stain.
Electron Microscopy
The middle section of the kidneys was cut into blocks of approximately 1 to 2 mm3 15 ,
and fixed overnight at 4°C in 2.5% glutaraldehyde in 1x PBS. The fixed tissue subsequently
was processed by the University of Leicester Electron Microscopy Facility
Cryostat sections
The other third of the kidneys was, cut into blocks approximately 1 to 2 mm3
and
snap frozen in liquid nitrogen and kept at -80°C for cryostat sections and mRNA analysis.
Results:
FIGURE 45 graphically illustrates the percent survival of saline-treated control mice
(n=5) and anti-MASP-2 antibody-treated mice (n=5) in the STX/LPS-induced model over
time (hours). Notably, as shown in FIGURE 45, all of the control mice died by 42 hours. In
sharp contrast, 100 % of the anti-MASP-2 antibody-treated mice survived throughout the
time course of the experiment. Consistent with the results shown in FIGURE 45, it was
observed that all the untreated mice that either died or had to be culled with signs of severe
disease had significant glomerular injuries, while the glomeruli of all anti-MASPtreated
mice looked normal (data not shown). These results demonstrate that MASP-2 inhibitors,
such as anti-MASP-2 antibodies, may be used to treat subjects suffering from, or at risk for
developing a thrombotic microangiopathy (TMA), such as hemolytic uremic syndrome
(HUS), atypical HUS (aHUS), or thrombotic thrombocytopenic purpura (TTP).
EXAMPLE 37
This Example describes the effect of MASP-2 deficiency and MASP-2 inhibition in a
murine FITC-dextran/light induced endothelial cell injury model of thrombosis.
Background/Rationale: As demonstrated in Examples 35 and 36, MASP-2 deficiency
(MASP-2 KO) and MASP-2 inhibition (via administration of an inhibitory MASP-2
antibody) protects mice in a model of typical HUS, wherease all control mice exposed to
STX and LPS developed severe HUS and became moribund or died within 48 hours. For
example, as shown in FIGURE 54, all mice treated with a MASP-2 inhibitory antibody and
then exposed to STX and LPS survived (Fisher’s exact p<0.01; N=5). Thus, anti-MASP-2
therapy protects mice in this model of HUS.
The following experiments were carried out to analzye the effect of MASP-2
deficiency and MASP-2 inhibition in a fluorescein isothiocyanate (FITC)-dextran-induced
endothelial cell injury model of thrombotic microangiopathy (TMA) in order to demonstrate
further the benefit of MASP-2 inhibitors for the treatment of HUS, aHUS, TTP, and TMA’s
with other etiologies.
Methods:
Intravital microscopy
Mice were prepared for intravital microscopy as described by Frommhold et al., BMC
Immunology 12:56-68, 2011. Briefly, mice were anesthetized with intraperitoneal (i.p.)
injection of ketamine (125 mg/kg bodyweight, Ketanest, Pfitzer GmbH, Karlsruhe,
Germany) and xylazine (12.5 mg/kg body weight; Rompun, Bayer, Leverkusen, Germany)
and placed on a heating pad to maintain body temperature at 37°C. Intravital microscopy
was conducted on an upright microscope (Leica, Wetzlar, Germany) with a saline immersion
objective (SW 40/0.75 numerical aperture, Zeiss, Jena, Germany). To ease breathing, mice
were intubated using PE 90 tubing (Becton Dickson and Company, Sparks, MD, USA). The
left carotid artery was cannuled with PE10 tubing (Becton Dickson and Company, Sparks,
MD, USA) for blood sampling and systemic monoclonal antibody (mAb) administration.
Cremaster muscle preparation
The surgical preparation of the cremaster muscle for intravital microscopy was
performed as described by Sperandio et al., Blood, 97:3812-3819, 2001. Briefly, the scrotum
was opened and the cremaster muscle mobilized. After longitudinal incision and spreading
of the muscle over a cover glass, the epididymis and testis were moved and pinned to the
side, giving full microscopic access to the cremaster muscle microcirculation. Cremaster
muscle venules were recorded via a CCD camera (CF8/1; Kappa, Gleichen, Germany) on a
Panasonic S-VHS recorder. The cremaster muscle was superfused with thermo-controlled
(35°C bicarbonate-buffered saline) as previously described by Frommhold et al., BMC
Immunology 12:56-68, 20112011.
Light excitation FITC dextran injury model
A controlled, light-dose-dependent vascular injury of the endothelium of cremaster
muscle venules and arterioles was induced by light excitation of phototoxic (FITC)-dextran
(Cat. No. FD150S, Sigma Aldrich, Poole, U.K.). This procedure initiates localized
thrombosis. As a phototoxic reagent, 60 µL of a 10% w/v solution of FITC–dextran was
injected through the left carotid artery access and allowed to spread homogenously
throughout the circulating blood for 10 minutes. After selecting a well-perfused venule,
halogen light of low to midrange intensity (800-1500) was focused on the vessel of interest
to induce FITC-dextran fluorescence and mild to moderate phototoxicity to the endothelial
surface in order to stimulate thrombosis in a reproducible, controlled manner. The necessary
phototoxic light intensity for the excitation of FITC-dextran was generated using a halogen
lamp (12V, 100W, Zeiss, Oberkochen, Germany). The phototoxicity resulting from lightinduced excitation of the fluorochrome requires a threshold of light intensity and/or duration
of illumination and is caused by either direct heating of the endothelial surface or by
generation of reactive oxygen radicals as described by Steinbauer et al., Langenbecks Arch
Surg 385:290-298, 2000.
The intensity of the light applied to each vessel was measured for adjustment by a
wavelength-correcting diode detector for low power measurements (Labmaster LM-2,
Coherent, Auburn, USA). Off-line analysis of video scans was performed by means of a
computer assisted microcirculation analyzing system (CAMAS, Dr. Zeintl, Heidelberg) and
red blood cell velocity was measured as described by Zeintl et al., Int J Microcirc Clin Exp,
8(3):293-302, 2000.
Application of monoclonal anti-human MASP-2 inhibitory antibody (mAbH6)
and vehicle control prior to induction of thrombosis
Using a blinded study design, 9-week-old male C57BL/6 WT littermate mice were
given i.p. injections of either the recombinant monoclonal human MASP-2 antibody
(mAbH6), an inhibitor of MASP-2 functional activity (given at a final concentration of
10mg/kg body weight), or the same quantity of an isotype control antibody (without MASP-2
inhibitory activity) 16 hours before the phototoxic induction of thrombosis in the cremaster
model of intravital microscopy. One hour prior to thrombosis induction, a second dose of
either mAbH6 or the control antibody was given. MASP-2 knockout (KO) mice were also
evaluated in this model.
mAbH6 (established against recombinant human MASP-2) is a potent inhibitor of
human MASP-2 functional activity, which cross-reacts with, binds to and inhibits mouse
MASP-2 but with lower affinity due to its species specificity (data not shown). In order to
compensate for the lower affinity of mAbH6 to mouse MASP-2, mAbH6 was given at a high
concentration (10mg/kg body weight) to overcome the variation in species specificity, and
the lesser affinity for mouse MASP-2, to provide effective blockade of murine MASP-2
functional activity under in vivo conditions.
In this blinded study, the time required for each individual venuole tested (selection
criteria were by comparable diameters and blood flow velocity) to fully occlude was
recorded.
The percentage of mice with microvascular occlusion, the time of onset, and the time
to occlusion were evaluated over a 60-minute observation period using intravital microscopy
video recordings.
Results:
FIGURE 46 graphically illustrates, as a function of time after injury induction, the
percentage of mice with microvascular occlusion in the FITC/Dextran UV model after
treatment with isotype control or human MASP-2 antibody mAbH6 (10mg/kg) dosed at 16
hours and 1 hour prior to injection of FITC/Dextran. As shown in FIGURE 46, 85% of the
wild-type mice receiving the isotype control antibody occluded within 30 minutes or less,
whereas only 19% of the wild-type mice pre-treated with the human MASP-2 antibody
(mAbH6) occluded within the same time period, and the time to occlusion was delayed in the
mice that did eventually occlude in the human MASP-2 antibody-treated group. It is further
noted that three of the MASP-2 mAbH6 treated mice did not occlude at all within the 60-
minute observation period (i.e., were protected from thrombotic occlusion).
FIGURE 47 graphically illustrates the occlusion time in minutes for mice treated with
the human MASP-2 antibody (mAbH6) and the isotype control antibody. The data are
reported as scatter-dots with mean values (horizontal bars) and standard error bars (vertical
bars). This figure shows the occlusion time in the mice where occlusion was observable.
Thus, the three MASP-2 antibody-treated mice that did not occlude during the 60 minute
observation period were not included in this analysis (there was no control treated mouse that
did not occlude). The statistical test used for analysis was the unpaired t test; wherein the
symbol “*” indicates p=0.0129. As shown in FIGURE 47, in the four MASP-2 antibody
(mAbH6)-treated mice that occluded, treatment with MASP-2 antibody significantly
increased the venous occlusion time in the FITC-dextran/light-induced endothelial cell injury
model of thrombosis with low light intensity (800-1500) as compared to the mice treated
with the isotype control antibody. The average of the full occlusion time of the isotype
control was 19.75 minutes, while the average of the full occlusion time for the MASP-2
antibody treated group was 32.5 minutes.
FIGURE 48 graphically illustrates the time until occlusion in minutes for wild-type
mice, MASP-2 KO mice, and wild-type mice pre-treated with human MASP-2 antibody
(mAbH6) administered i.p. at 10mg/kg 16 hours before, and then administered again i.v.1
hour prior to the induction of thrombosis in the FITC-dextran/light-induced endothelial cell
injury model of thrombosis with low light intensity (800-1500). Only the animals that
occluded were included in FIGURE 48; n=2 for wild-type mice receiving isotype control
antibody; n=2 for MASP-2 KO; and n=4 for wild-type mice receiving human MASP-2
antibody (mAbH6). The symbol “*” indicates p<0.01. As shown in FIGURE 48, MASP-2
deficiency and MASP-2 inhibition (mAbH6 at 10mg/kg) increased the venous occlusion time
in the FITC-dextran/light-induced endothelial cell injury model of thrombosis with low light
intensity (800-1500).
Conclusions:
The results in this Example further demonstrate that a MASP-2 inhibitory agent that
blocks the lectin pathway (e.g., antibodies that block MASP-2 function), inhibits
microvascular coagulation and thrombosis, the hallmarks of multiple microangiopathic
disorders, in a mouse model of TMA. Therefore, it is expected that administration of a
MASP-2 inhibitory agent, such as a MASP-2 inhibitory antibody, will be an effective
therapy in patients suffering from HUS, aHUS, TTP, or other microangiopathic disorders and
provide protection from microvascular coagulation and thrombosis.
EXAMPLE 38
This Example describes a study demonstrating that human MASP-2 inhibitory
antibody (mAbH6) has no effect on platelet function in platelet-rich human plasma.
Background/Rationale: As described in Example 37, it was demonstrated that MASP-2
inhibition with human MASP-2 inhibitory antibody (mAbH6) increased the venous occlusion
time in the FITC-dextran/light-induced endothelial cell injury model of thrombosis. The
following experiment was carried out to determine whether the MASP-2 inhibitory antibody
(mAbH6) has an effect on platelet function.
Methods: The effect of human mAbH6 MASP-2 antibody was tested on ADP-induced
aggregation of platelets as follows. Human MASP-2 mAbH6 at a concentration of either 1
µg/ml or 0.1 µg/ml was added in a 40 µL solution to 360 µL of freshly prepared platelet-rich
human plasma. An isotype control antibody was used as the negative control. After adding
the antibodies to the plasma, platelet activation was induced by adding ADP at a final
concentration of 2 µM. The assay was started by stirring the solutions with a small magnet
in the 1 mL cuvette. Platelet aggregation was measured in a two-channel Chrono-log Platelet
Aggregometer Model 700 Whole Blood/Optical Lumi-Aggregometer.
Results:
The percent aggregation in the solutions was measured over a time period of five minutes.
The results are shown below in TABLE 13.
TABLE 13: Platelet Aggregation over a time period of five minutes.
Antibody Amplitude
(percent aggregation)
Slope
(percent
aggregation over
time)
MASP-2 antibody (mAbH6)
(1 µg/ml)
46% 59
Isotype control antibody
(1 µg/ml)
49% 64
MASP-2 antibody (mAbH6)
(0.1 µg/ml)
52% 63
Isotype control antibody
(0.1 µg/ml)
46% 59
As shown above in TABLE 13, no significant difference was observed between the
aggregation of the ADP-induced platelets treated with the control antibody or the MASP-2
mAbH6 antibody. These results demonstrate that the human MASP-2 antibody (mAbH6)
has no effect on platelet function. Therefore, the results described in Example 37
demonstrating that MASP-2 inhibition with human MASP-2 inhibitory antibody (mAbH6)
increased the venous occlusion time in the FITC-dextran/light-induced endothelial cell injury
model of thrombosis, were not due to an effect of mAbH6 on platelet function. Thus,
MASP-2 inhibition prevents thrombosis without directly impacting platelet function,
revealing a therapeutic mechanism that is distinct from existing anti-thrombotic agents.
EXAMPLE 39
This Example describes the effect of MASP-2 inhibition on thrombus formation and
vessel occlusion in a murine model of TMA.
Background/Rationale: The lectin pathway plays a dominant role in activating the
complement system in settings of endothelial cell stress or injury. This activation is amplified
rapidly by the alternative pathway, which is dysregulated in many patients presenting with
aHUS. Preventing the activation of MASP-2 and the lectin pathway is thus expected to halt
the sequence of enzymatic reactions that lead to the formation of the membrane attack
complex, platelet activation, and leukocyte recruitment. This effect limits tissue damage.
In addition, MASP-2 has Factor Xa-like activity and cleaves prothrombin to form thrombin.
This MASPdriven activation of the coagulation system may imbalance hemostasis and
result in the pathology of TMA. Thus, inhibition of MASP-2 using a MASP-2 inhibitor, such
as a MASP-2 inhibitory antibody that blocks activation of the complement and coagulation
systems is expected to improve outcomes in aHUS and other TMA-related conditions.
As described in Example 37, it was demonstrated that MASP-2 inhibition with human
MASP-2 inhibitory antibody (mAbH6) increased the venous occlusion time in the FITCdextran/light-induced endothelial cell injury model of thrombosis. In this model of TMA,
mice were sensitized by IV injection of FITC- dextran, followed by localized photoactivation of the FITC- dextran in the microvasculature of the mouse cremaster muscle
(Thorlacius H et al., Eur J Clin. Invest 30(9):804-10, 2000; Agero et al., Toxicon 50(5):698-
706, 2007).
The following experiment was carried out to determine whether the MASP-2 inhibitory
antibody (mAbH6) has a dose-response effect on thrombus formation and vessel occlusion in
a murine model of TMA.
Methods: Localized thrombosis was induced by photo-activation of fluorescein
isothiocyanate-labeled dextran (FITC-dextran) in the microvasculature of the cremaster
muscle of C57 Bl/6 mice and intravital microscopy was used to measure onset of thrombus
formation and vessel occlusion using methods described in Example 37, with the following
modifications. Groups of mice were dosed with mAbH6 (2mg/kg, 10 mg/kg or 20 mg/kg) or
isotype control antibody (20 mg/kg) were administered by intravenous (iv) injection one hour
before TMA induction. The time to onset of thrombus formation and time to complete vessel
occlusion were recorded. Video playback analysis of intravital microscopy images recorded
over 30 to 60 minutes was used to evaluate vessel size, blood flow velocity, light intensity,
rate of onset of thrombus formation as equivalent of platelet adhesion, time to onset of
thrombus formation, rate of total vessel occlusion and time until total vessel occlusion.
Statistical analysis was conducted using SigmaPlot v12.0.
Results:
Initiation of Thrombus Formation
FIGURE 49 is a Kaplan-Meier plot showing the percentage of mice with thrombi as a
function of time in FITC-Dextran induced thrombotic microangiopathy in mice treated with
increasing doses of human MASP-2 inhibitory antibody (mAbH6 at 2 mg/kg, 10mg/kg or 20
mg/kg) or an isotype control antibody. As shown in FIGURE 49, initiation of thrombus
formation was delayed in the mAbH6-treated mice in a dose-dependent manner relative to
the control-treated mice.
FIGURE 50 graphically illustrates the median time to onset (minutes) of thrombus formation
as a function of mAbH6 dose (*p<0.01 compared to control). As shown in FIGURE 50, the
median time to onset of thrombus formation increased with increasing doses of mAbH6 from
6.8 minutes in the control group to 17.7 minutes in the 20 mg/kg mAbH6 treated group
(p<0.01). The underlying experimental data and statistical analysis are provided in TABLES
14 and 15.
The time to onset of thrombus formation in individual mice recorded based on evaluation of
the videographic recording is detailed below in TABLE 14.
TABLE 14: Time to Onset of Thrombus Formation After Light Dye-induced Injury
Control Treatment mAbH6 Treatment
Time to Onset
(minutes)
Control 2 mg/kg 10 mg/kg 20 mg/kg
6.07 5.93 12.75 10.00
1.07 6.95 2.53 10.33
8.00 8.92 14.00 21.00
2.40 11.92 3.05 11.50
8.48 12.75 8.00 19.00
4.00 12.53 8.17 10.37
4.00 15.83 22.65
7.83 11.70 16.37
6.83 50.67 21.75*
.00 32.25*
.67
* vessels did not show onset during the indicated observation period
The statistical analysis comparing time to onset of occlusion between control and mAbH6
treated animals is shown below in TABLE 15.
TABLE 15: Time to Onset: data from FITC Dex dose response study
Statistic Control mAbH6
(2 mg/kg)
mAbH6
(10 mg/kg)
mAbH6
(20 mg/kg)
Number of events/number of
animals (%)
11/11
(100%)
6/6
(100%)
9/9
(100%)
8/10
(80.0%)
Median time (minutes) (95% CI) 6.8
(2.4, 8.5)
.4
(5.9, 12.8)
11.7
(2.5, 15.8)
17.7
(10.0, 22.7)
Wilcoxon p-value* 0.2364 0.1963 0.0016
Event=Time to onset observed
Median (minutes) and its 95% CI were based on Kaplan-Meier estimate
NE=not estimable
*p-values were adjusted by Dunnett-Hsu multiple comparison
Microvascular Occlusion
FIGURE 51 is a Kaplan-Meier plot showing the percentage of mice with microvascular
occlusion as a function of time in FITC-Dextran induced thrombotic microangiopathy in
mice treated with increasing doses of human MASP-2 inhibitory antibody (mAbH6 at 2
mg/kg, 10mg/kg or 20mg/kg) or an isotype control antibody. As shown in FIGURE 51,
complete microvascular occlusion was delayed in the mAbH6 treated groups as compared to
the control mice.
FIGURE 52 graphically illustrates the median time to microvascular occlusion as a function
of mAbH6 dose (*p<0.05 compared to control). As shown in FIGURE 52, the median time
to complete microvascular occlusion increased from 23.3 minutes in the control group to
38.6 minutes in the 2mg/kg mAbH6 treated group (p<0.05). Doses of 10 mg/kg or 20 mg/kg
of mAbH6 performed similarly (median time for complete microvascular occlusion was 40.3
and 38 minutes, respectively) to the 2 mg/kg mAbH6 treated group. The underlying
experimental data and statistical analysis are provided in TABLES 16 and 17.
The time to complete vessel occlusion in individual mice recorded based on primary
evaluation of the videographic recording is detailed below in TABLE 16.
TABLE 16: Time to Complete Occlusion After Light Dye-Induced Injury
Control Treatment mAbH6 Treatment
Time to
Occlusion
(minutes)
Control 2 mg/kg 10 mg/kg 20 mg/kg
37.50 42.3 30.92 38.00
29.07 21.91 17.53 28.00
27.12 24.4 51.38 40.58
19.38 31.38 36.88 33.00
19.55 61.17* 26.83 39.10
18.00 61.55* 40.28 32.03
16.50 55.83 38.53
23.33 71.93* 21.75*
14.83 98.22* 32.25*
* 33.17*
61.8*
*vessels did not completely occlude during the indicated observation period.
The statistical analysis comparing time to complete occlusion between control and mAbH6
treated animals is shown below in TABLE 17.
TABLE 17: Time to Complete Microvascular Occlusion: data from FITC Dex dose
response study
Statistic Control mAbH6
(2 mg/kg)
mAbH6
(10 mg/kg)
mAbH6
(20 mg/kg)
Number of events/number of
animals (%)
9/11
(81.8%)
4/6
(66.7%)
7/9
(77.8%)
7/10
(70.0%)
Median time (minutes) (95% CI) 23.3
(16.5, 37.5)
36.8
(21.9, NE)
40.3
(17.5, NE)
38.0
(28.0, 40.6)
Wilcoxon p-value* 0.0456 0.0285 0.0260
Event=Time to occlusion observed
Median (minutes) and its 95% CI were based on Kaplan-Meier estimate
NE=not estimable
*p-values were adjusted by Dunnett-Hsu multiple comparison
Summary
As summarized in TABLE 18, the initiation of thrombus formation was delayed in the
mAbH6 treated mice in a dose-dependent manner relative to the control-treated mice
(median time to onset 10.4 to 17.7 minutes vs 6.8 minutes). The median time to complete
occlusion was significantly delayed in all mAbH6-treated groups relative to the controltreated groups (Table 18).
TABLE 18: Median Time to Onset of Thrombus Formation and Complete Occlusion
Control mAbH6
(2 mg/kg)
mAbH6
(10 mg/kg)
mAbH6
(20 mg/kg)
Median# time to
onset of
thrombus
formation
(minutes)
6.8 10.4 11.7 17.7*
Median# time to
complete
microvascular
occlusion
(minutes)
23.3 36.8* 40.3* 38.0*
#Median values are based on Kaplan-Meier estimate
*p<0.05 compared to control (Wilcoson adjusted by Dunnett-Hsu for multiple comparisons)
These results demonstrate that mAbH6, a human monoclonal antibody that binds to
MASP-2 and blocks the lectin pathway of the complement system, reduced microvascular
thrombosis in a dose-dependent manner in an experimental mouse model of TMA.
Therefore, it is expected that administration of a MASP-2 inhibitory agent, such as a MASP2 inhibitory antibody, will be an effective therapy in patients suffering from HUS, aHUS,
TTP, or other microangiopathic disorders such as other TMAs including catastrophic
antiphospholipid syndrome (CAPS), systemic Degos disease, and TMAs secondary to
cancer, cancer chemotherapy and transplantation and provide protection from microvascular
coagulation and thrombosis.
While illustrative embodiments have been illustrated and described, it will be
appreciated that various changes can be made therein without departing from the range and
scope of the invention.
Claims (15)
1. Use of a MASP-2 inhibitory agent which inhibits MASPdependent complement activation in the manufacture of a medicament for treating a subject suffering 5 from Degos disease, wherein the MASP-2 inhibitory agent is a monoclonal MASP-2 inhibitory antibody, or antigen-binding fragment thereof, that specifically binds to a portion of SEQ ID NO:6 and selectively inhibits MASPdependent complement activation without substantially inhibiting the C1q-dependent complement pathway. 10
2. The use of Claim 1, wherein the subject has previously undergone, or is currently undergoing, treatment with a terminal complement inhibitor that inhibits cleavage of complement protein C5.
3. The use of claim 1, wherein the medicament is adapted for administration in 15 conjunction with a terminal complement inhibitor that inhibits cleavage of complement protein C5.
4. The use of Claim 3, wherein the terminal complement inhibitor is a humanized anti-C5 antibody or antigen-binding fragment thereof. 20
5. The use of Claim 3, wherein the terminal complement inhibitor is eculizumab.
6. The use of Claim 1, wherein the antibody or fragment thereof is selected from the group consisting of a recombinant antibody, an antibody having reduced effector 25 function, a chimeric antibody, a humanized antibody and a human antibody.
7. The use of Claim 1, wherein the medicament is formulated for administration subcutaneously, intra-muscularly, intra-arterially, intravenously, or as an inhalant. 30
8. Use of a MASP-2 inhibitory agent which inhibits MASPdependent complement activation in the manufacture of a medicament for treating a subject suffering from Catastrophic Antiphospholipid Syndrome (CAPS), wherein the MASP-2 inhibitory agent comprises a monoclonal MASP-2 inhibitory antibody, or antigen-binding fragment thereof, that specifically binds to a portion of SEQ ID NO:6 and selectively inhibits MASP2-dependent complement activation without substantially inhibiting the C1q-dependent 5 complement pathway.
9. The use of Claim 8, wherein the subject has previously undergone, or is currently undergoing, treatment with a terminal complement inhibitor that inhibits cleavage of complement protein C5. 10
10. The use of claim 8, wherein the medicament is adapted for administration in conjunction with a terminal complement inhibitor that inhibits cleavage of complement protein C5. 15
11. The use of Claim 10, wherein the terminal complement inhibitor is a humanized anti-C5 antibody or antigen-binding fragment thereof.
12. The use of Claim 10, wherein the terminal complement inhibitor is eculizumab. 20
13. The use of Claim 8, wherein the antibody or fragment thereof is selected from the group consisting of a recombinant antibody, an antibody having reduced effector function, a chimeric antibody, a humanized antibody and a human antibody. 25
14. The use of Claim 8, wherein the medicament is formulated for administrationsubcutaneously, intra-muscularly, intra-arterially, intravenously, or as an inhalant.
15. The use of Claim 1 or 8, substantially as herein described with reference to 30 any one of the Examples and/or
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