Classifications

• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07K—PEPTIDES
  • C07K14/00—Peptides having more than 20 amino acids; Gastrins; Somatostatins; Melanotropins; Derivatives thereof
  • C07K14/005—Peptides having more than 20 amino acids; Gastrins; Somatostatins; Melanotropins; Derivatives thereof from viruses
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61P—SPECIFIC THERAPEUTIC ACTIVITY OF CHEMICAL COMPOUNDS OR MEDICINAL PREPARATIONS
  • A61P31/00—Antiinfectives, i.e. antibiotics, antiseptics, chemotherapeutics
  • A61P31/12—Antivirals
  • A61P31/20—Antivirals for DNA viruses
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
  • A61K39/00—Medicinal preparations containing antigens or antibodies
• • C—CHEMISTRY; METALLURGY
  • C12—BIOCHEMISTRY; BEER; SPIRITS; WINE; VINEGAR; MICROBIOLOGY; ENZYMOLOGY; MUTATION OR GENETIC ENGINEERING
  • C12N—MICROORGANISMS OR ENZYMES; COMPOSITIONS THEREOF; PROPAGATING, PRESERVING, OR MAINTAINING MICROORGANISMS; MUTATION OR GENETIC ENGINEERING; CULTURE MEDIA
  • C12N2730/00—Reverse transcribing DNA viruses
  • C12N2730/00011—Details
  • C12N2730/10011—Hepadnaviridae
  • C12N2730/10111—Orthohepadnavirus, e.g. hepatitis B virus
  • C12N2730/10122—New viral proteins or individual genes, new structural or functional aspects of known viral proteins or genes

Definitions

• the present invention relates to polypeptides derived from a hepatitis B virus envelope glycoprotein, termed hepatitis B surface antigen, which compete with the interaction between hepatitis B surface antigen and the phospholipid-binding protein annexin V.
• the present invention also concerns the use of these polypeptides, and antibodies against them, in order to diagnose, treat and vaccinate against, an infection with hepatitis B virus and hepatitis delta virus.
• Hepatitis B virus belongs to the Hepadnaviridae which are characterized by a significant hepatotropism and species specificity.
• Hepatitis delta virus represents a naturally occurring subviral satellite of HBV (Rizetto et al, 1986). HBV causes major medical problems, such as chronic liver disease and hepatocellular carcinoma (Schroder & Zentgraf, 1990). HDV su erinfection is usually more severe compared to HBV infection solely. It is estimated that there are 300 million human carriers ofthe virus worldwide, while in the US only 70,000 carriers are coinfected with HDV.
• Genotypes A to F of HBV are designated based on this sequence divergence (for review, see Magnius & Norder, 1995).
• the HBV envelope consists of three related glycoproteins, termed hepatitis B surface antigens (HBsAg), which are the product ofthe S gene: 1) the "small" transmembrane protein, also termed major protein or small S-protein, composed of 226 amino acids (aa), 2) the "middle” protein which comprises the small S-protein and 55 additional aa at the N-terminus corresponding to the pre-S2 region of the S gene, and 3) the "large” protein composed of 389 or 400 aa corresponding to the following regions: S + pre-S2 + pre-Sl (108-119 N-terminal aa) (Heerman et aL, 1984; Robinson et al, 1987).
• the envelope of HDV is also entirely derived from HBV and consists predominantly of small HbsAg, 5-10% of middle HbsAg and no or less then 1% of large HbsAg (Bonino et al, 1986).
• the region composed of aa 100 to 160 of "small” HBsAg has been predicted to be located on the outer surface ofthe virus (for review, see Beiting et al, 1995).
• Current vaccines, using recombinant "small” HBsAg result in a protective antibody response directed against a limited number of epitopes such as the major "a" deteraiinant: aa 139-147.
• the latter determinant is shown to be the most immimodominant epitope within the region aa 100-160 of "small” HBsAg (for review, see Magnius & Norder, 1995, and, Howard & Allison, 1995).
• Annexin V (also termed endonexin ⁇ , placental anticoagulant protein, PP4 or lipocortin V) is a member ofthe family of structurally related Ca ⁇ -dependent phosphohpid-binding proteins, known as annexins, which have molecular weights between 32 and 67 kDa (Klee, 1988; Zaks & Creutz, 1990). Annexin V is found in various tissues such as liver, spleen, lung, intestine and placenta (Walker et al, 1990).
• annexin V behaves like an integral membrane protein and forms calcium- selective cation channels (Rojas et al, 1990; Bianchi et al, 1992). We have recently shown that annexin V, present on human liver plasma membranes.
• HBsAg specifically binds to "small" HBsAg in a Ca 2+ -dependent manner (Hertogs et al, 1993; WO 94/01554).
• the receptor-ligand relationship between HBsAg and annexin V is further supported by the observation that rabbits, irmnunized with native human hver annexin V or recombinant annexin V, or chickens, immunized with F(ab') 2 -fragments of rabbit anti-annexin V IgG, spontaneously develop anti-idiotypic antibodies (Ab2) which specifically recognize HBsAg
• a polypeptide, used in a vaccine composition, which might provide a better protection is very likely derived from a viral antigen which plays a crucial role for survival ofthe virus.
• annexin V binds HBsAg and, thus, might play a vital role in the initiation of HBV and HDV infection
• the annexin V-binding domain on HBsAg may not be subject to major mutations. This is in contrast to the "a" determinant on HBsAg for which many escape variants have already been characterized (Carman et al, 1990). In other words, the development of escape mutants in the annexin V-binding domain of HBsAg is unlikely.
• the present invention aims at providing a polypeptide derived from HBsAg, which competes with the HBsAg/annexin V interaction or which binds a compound or antibody competing with the HBsAg/annexin V interaction, and is immunogenic. More specifically, the present invention aims at providing a polypeptide as described above which comprises less than 61 amino acids containing at least 4 amino acids of one of the following sequences: FAKYLWEWASVR,
• KTCTTPAQGN and TTPAQGN mapping such a polypeptide is not an obvious undertaking.
• engineering a peptide in such a way that it evokes upon immunization a specific response against the annexin V-binding epitope or a part thereof, is not obvious at all.
• the present invention further aims at providing a polypeptide which comprises the sequence KTCTTPAQGN or TTPAQGN, and the sequence FAKYLWEWASVR, or functionally equivalent parts or variants of siad sequences.
• the present invention also aims at providing a vaccine composition which comprises as an active substance a polypeptide as described above. Furthermore, the present invention aims at providing a vaccine composition as described above for use as an inoculum to vaccinate humans against infection with HBV and/or HDV or any mutated strain thereof or to therapeutically vaccinate human earners of HBV and/or HDV or any mutated strain thereof.
• the reason to be able to therapeutically vaccinate earners of HBV using the above-described vaccine composition is based on our surprising observation that the polypeptide derived from HBV, as described above, evokes a specific antibody response against this polypeptide whereas a natural HBV infection in a control chimpanzee (see Example 5) does not result in the production of such antibodies. In other words, the inoculation of the above- described vaccine composition during an infection with HBV results in a better immune response and hence a better protection.
• the present invention also aims at providing a polypeptide as described above or any mutated version thereof which, upon inoculation in a mammalian host, results in the production of antibodies which specifically bind to said polypeptide, in particular to the sequence
• KTCTTPAQGN or a part thereof or, to the sequence TTPAQGN or a part thereof, or, to t he sequence FAKYLWEWASVR or a part thereof
• the present invention also aims at providing a combination of a polypeptide according to any ofthe previous aims and a negatively charged phospholipid.
• the present invention aims at providing a polypeptide composition comprising any combination of polypeptides as defined above.
• the present invention also aims at providing antibodies or fragments thereof which specifically bind to a polypeptide as defined above and inhibit binding of said polypeptide to annexin V.
• the present invention further aims at providing a pharmaceutical composition comprising as an active substance the antibodies or fragments thereof as defined above for use in a method to treat humans infected with HBV and/or HDV or any mutated strain thereof.
• the present invention aims at providing a method, using a polypeptide as defined above, to detect antibodies which are capable of competing with the HBsAg/annexin V interaction and which are present in a biological sample, comprising: a) contacting the biological sample to be analysed for the presence of HBsAg antibodies with a polypeptide as defined above, b) detecting the immunological complex formed between said antibodies and said polypeptide.
• the present invention also aims at providing a pharmaceutical composition comprising as an active substance a polypeptide as defined above for use in a method to treat humans infected with HBV and/or HDV or any mutated strain thereof
• the present invention aims at a polypeptide as defined above for use in a method to screen for drugs which block the binding between annexin V and said polypeptide.
• the present invention also aims at providing polypeptides as defined above for use as a medicament to treat humans infected with hepatitis B virus and/or hepatitis delta virus or any mutated strain thereof
• the present invention finally aims at providing a kit for the in vitro determination of antibodies to HBsAg present in human serum containing: at least one microplate, polypeptides as defined above, appropriate buffer, blocking and washing solutions which favor binding of said polypeptides with the antibodies in human serum samples, and appropriate markers which allow to determine the complexes formed between the antibodies in human serum samples and said polypeptides.
• Table 1 provides sequence information concerning the region aa 99 to 169 of "small" HBsAg which determines four genotypes of HBsAg (A,B,C and D) and regarding the polypeptides which were examined for binding to annexin V and to several antibodies and for their immunogenicity in cliimpanzee and rabbits.
• Table 2 shows the relative affinity of peptides for binding the the anti-HBsAg monoclonal C11F5. Briefly binding of C11F5 to HBsAg coated on microtiterplates is competed with the peptides IGP 1076-1083 in soloution. The molar concentration of HBsAg itself yielding a 50% competition is equal to 1.
• Figure 1 shows the influence of anti-idiotypic antibodies (Ab2) on the production of HBsAg in culture medium of primary cultures of adult human hepatocytes infected with HBV.
• HBsAg production of infected cells at days 3, 5, 7, 8 and 10 post-infection in the absence of anti-idiotypic antibodies is represented by "O”.
• Results of HBsAg production in media of non-infected cells or of cells infected in the presence of anti-idiotypic antibodies are represented by "+” and " * ⁇ ", respectively.
• the findings presented are the average of results obtained from five experiments.
• Figure 2 demonstrates that anti-idiotypic antibodies (Ab2) which specifically recognize the annexin V binding domain of HBsAg prevent HBV infection in primary cultures of human hepatocytes in vitro.
• the figure represents an autoradiogram ofthe Southern blot analysis of HBV-DNA and replicative intermediates in primary cultures of human hepatocytes infected with HBV in the presence and absence of anti-idiotypic antibodies.
• Integrated HBV-DNA sequences were present in HepG2.2.15 (a HepG2 cell line transfected with the HBV genome (Sells et al, 1987) (lane 1).
• HBV-DNA replicative intermediates were detected in cells infected with HBV inoculum in the absence of anti-idiotypic antibodies (lane 4).
• Lane 2 and 3 represent the results of HBV-DNA detection in experiments without HBV inoculum and in parallel experiments in the presence of anti-idiotypic antibodies, respectively.
• Figure 3 demonstrates the binding of an anti-idiotypic antibodies (Ab2), which mimic annexin V, to the polypeptides indicated in table 1 and "small" HBsAg.
• Ab2 anti-idiotypic antibodies
• the polypeptides or HBsAg were adsorbed to microtiterplates which were incubated after blocking with a serial dilution of Ab2 (1/50 to 1/5000). Binding of Ab2 was visualized using an anti-rabbit IgG preparation conjugated with peroxidase. Plates were developed using tetramethylbenzidine as colour reagent, finally plates were read at 450 nm.
• Figure 4 shows the binding of Ab2 to biotinilated forms of some ofthe polypeptides indicated in table 1. Briefly, streptavidin was adsorbed to microtiterplates which were incubated after blocking with biotinilated peptides, followed by an incubation with serial dilutions of Ab2 (1/50 to 1/5000). Binding of Ab2 was visualized using an anti-rabbit IgG preparation conjugated with peroxidase. Plates were developed using tetramethylbenzidine as colour reagent, finally plates were read at 450 nm.
• Figure 5 shows that HBsAg of either genotypes A or D binds Ab2 and annexin V. Briefly, a serial dilution of HBsAg was coated on microtiterplates. After blocking the plates were incubated with
• Figure 6 Binding of horse radish peroxidase (HRPO) labelled recombinant human A-V to solid phase HBsAg in the presence of a serial dilution of phosphatidylserine (open symbols) or phosphatidylcholine (closed symbols).
• HRPO horse radish peroxidase
• Figure 7 Binding of HRPO labelled A-V to HBsAg in the presence of a serial dilution of mAbs directed against human A-V (U4C8: open triangles, U1E10: closed triangles, E1E8: open circles, CM1995: closed circles).
• Figure 8 Relative inhibition, expressed as % of competition, to a positive control (experiment without competitor) ofthe binding of HRPO labelled A-V to solid phase mAb in the presence of a 75 molar excess of unlabelled rat or human A-V (CM1995: open bars, U4C8: hatched bars, U1E10: closed bars).
• Figure 9 Relative inhibition, expressed as % of competition, to a positive control (experiment without competitor) ofthe binding HRPO labelled recombinant human A-V to solid phase mAb in the presence of excess of phosphatidylserine (open bars) or phosphatidylcholine (hatched bars) (ratio phosphoHpid/mAb is 30 (w/w)).
• Figure 10 Visual impression of binding between HBsAg and A-V and ofthe binding sites of all inhibiting antibodies.
• Figure 11 shows the antibody response of a chimpanzee vaccinated with some ofthe polypeptides indicated in table 1. Briefly, streptavidin or HBsAg was adsorbed to microtiterplates, strepta ⁇ idin coated wells were incubated after blocking with biotinilated peptides (IGP 1103, 1119 and the control peptides 1030 and 1038), followed by an incubation with a serial dilution ofthe vaccinated cl ⁇ npanzee serum (1/20 to 1/2560). Binding was visualized using an anti-human IgG preparation conjugated with peroxidase.
• biotinilated peptides IGP 1103, 1119 and the control peptides 1030 and 1038
• IgG antibodies of humans and chimpanzees show sufficient CToss-reactrvity so that chimpanzee IgG's can be detected using anti- human IgG conjugates. Plates were developed using tetramethylbenzidine as colour reagent, finally plates were read at 450 nm.
• Figure 12 demonstrates the evolution of antibody titer of a chimpanzee vaccinated with the polypeptides IGP 1103 and 1119 as described in table 1. Briefly, streptavidin or HBsAg was adsorbed to microtiterplates, streptavidin coated wells were incubated after blocking with biotinilated peptides (IGP 1103, 1119), followed by an incubation with a serial dilution ofthe vaccinated chimpanzee serum (1/20 to 1/2560). Binding was visualized using an anti-human IgG preparation conjugated with peroxidase. Plates were developed using tetramethylbenzidine as colour reagent, finally plates were read at 450 nm Titer is expressed as the serum dilution still giving a positive signal compared to a negative control.
• Figure 13 shows the antibody response of a chimpanzee challenged with HBV. Briefly, streptavidin or HBsAg was adsorbed to microtiterplates, streptavidin coated wells were incubated after blocking with biotinilated peptides (IGP 1103, 1119 and the control peptides 1030 and
• Figure 14 shows the cross reactivity of antibodies evoked by a genotype A derived peptide. Briefly, streptavidin was adsorbed to microtiterplates which were incubated after blocking with biotinilated peptides, followed by an incubation with a serial dilution of chimpanzee serum (1/2 4 to 1/2 13 ). Binding of cMmpanzee antibodies was visualized using an anti-human IgG preparation conjugated with peroxidase. Plates were developed using tetramethylbenzidine as colour reagent, finally plates were read at 450 nm. IGP 1030 represents a control peptide not related to HbsAg.
• Figure 15 shows binding of annexin V to HBsAg peptides representing the amino acid region 112-169. Briefly, binding of annexin V (coupled with horse radish peroxidase) to HBsAg itself or to the biotinylated peptides IGP 671, 673 and 80 (representing the aa region 112-169), the control peptide IGP 1038 and the peptide binding with the anti-idiotypic antibody (IGP 1119) coated to microtiterplates as a streptavidin complex was evaluated.
• annexin V coupled with horse radish peroxidase
• Figure 16 shows further fine mapping ofthe annexin V binding site on HBsAg. Briefly, binding of a new series of peptides (IGP 1189-1193, IGP 1190- 1192 being hetero-branched peptides, see Table 1) to annexin V was analysed as described above for Figure 15.
• Figure 17 shows further fine mapping of the annexin V binding site on HBsAg by direct competition. Briefly, binding of annexin V to HBsAg coated on microtiterplates is competed with HBsAg and with the peptides IGP 1119 and IGP 1193 in solution (both peptides are presented as streptavidin complexes).
• Figure 18 shows further fine mapping ofthe Ab2 epitope. Briefly binding of Ab2 to coated on microtiterplates is competed with the peptides P467-P471 in solution.
• Figure 19 shows the mapping ofthe epitope for the monoclonal anti-HBsAg antibody, Cl 1F5. Briefly peptides were adsorbed to microtiterplates as streptavidin complexes. Binding of C 11F5 was visualized using a goat-anti-mouse antibody conjugated to peroxidase.
• Figure 20 shows the binding of annexin V to peptides containing the HBsAg region 158-169. Briefly binding was performed as described for figure 15, but binding was performed at room temperature instead of 37°C, this in order to select for stronger binding peptides.
• Figure 21 shows the relative affinity of peptides for binding to annexin V. Briefly, binding of annexin V to HBsAg coated on microtiterplates is competed with a 200 or 20 molar excess of peptide in solution.
• Figure 22 shows the mapping ofthe antibody response of chimpanzee and rabbit against he epitope region 115-134. Briefly peptides were adsorbed to microtiterplates as streptavidin complexes. Binding of antibodies was visualized using a rabbit- anti-human or goat-anti-rabbit antibody conjugated to peroxidase.
• Figure 23 shows the mapping ofthe antibody response of rabbit against different peptides (IGP 1273 and 1274) containing the epitope region 158-169. Briefly peptides were adsorbed to microtiterplates as streptavidin complexes. Binding of antibodies wasbased on a rabbit- anti-human or goat-anti-rabbit antibody conjugated to peroxidase.
• the present invention is based on the finding of a polypeptide derived from HBsAg which competes with the HBsAg/annexin V interaction, or which binds a compound or antibody competing with this interaction, and is immunogenic. Accordingly, this polypeptide, and antibodies against it, can be used to prevent, diagnose or treat HBV and/or HDV infection.
• this polypeptide, and antibodies against it can be used to prevent, diagnose or treat HBV and/or HDV infection.
• the usage of the terms ' ⁇ BV and/or FEW ' indicate that an infection with HBV can occur solely or can be accompanied by a superinfection with HDV.
• an infection with HDV does not occur solely.
• the polypeptides ofthe present invention, and antibodies against them can be used to prevent, diagnose or treat a HBV infection solely or a mixed HB V/HDV infection.
• HBsAg is a known antigen (Heerman et al, 1984; Robinson et al, 1987). Based on this knowledge, polypeptides derived from HBsAg, as herein described, can be prepared by any method known in the art such as classical chemical synthesis, as described by Houbenweyl (1974) and Atheiton & Shepard (1989), or by means of recombinant DNA techniques as described by Maniatis et al. (1982). As used herein, the terms "polypeptides derived from HBsAg” refer to polypeptides having an aa sequence which is equal or similar to a part of the aa sequence of "small" HBsAg.
• polypeptides derived from HBsAg' 1 can be derived fiom any genotype of HBV (genotype A to F, see Example 6).
• polypeptide refers to a polymer of aa which comprises less aa in its sequence than HBsAg, more specifically to a polypeptide which comprises preferentially less than 226, 200, 190, 180, 170, 160, 150, 140, 130, 120, 110, 100, 90 or 80 aa, and most preferably less than 70 aa.
• polypeptides containing one or more analogues of an aa including unnatural aa's
• polypeptides with substituted linkages include mutated versions or natural sequence variations ofthe polypeptides (co ⁇ esponding to the genotypes A to F of HBV, as indicated above), polypeptides containing disulfide bounds between cysteine residues, as well as other modifications known in the art.
• polypeptides as set out above are particularly characterized in that they bind anti- idiotypic antibodies (Ab2) which compete with the binding of HBsAg to Annexin V as set out in the Example section or that they bind directly with annexin V.
• Ab2 anti- idiotypic antibodies
• immunogenic polypeptide relate to the ability ofthe polypeptide to provoke an immune response such as antibody production. These terms further imply that the polypeptide contains a B cell and /or T cell epitope.
• the present invention relates to a polypeptide as defined above which comprises preferentially less than 61, 55, 51, 45, 41, 35, 31 or 25 aa, and most preferably less than 21 aa and includes one ofthe following sequences: KTCTTPAQGN (SEQ LD NO 2, also referred to as “aa 122-131”), or 9, 8, 7, 6, 5 or 4 aa thereof, or, FAKYLWEWASVR (SEQ LD NO 35, also referred to as "aa 158-169"), or 11, 10, 9, 8, 7, 6, 5 or 4 aa thereof; or, TTPAQGN (SEQ ID 37. also referred to as "aa 125-131 ) or 6.
• the present invention relates, with regaid to the polypeptides comprising 4 to 9 aa derived fiom the sequence aa 122-131 (SEQ LD NO 2) as defined above, to peptides with the following aa sequence: aa 122- 125, aa 123-126, aa 124-127, aa 125-128, aa 126-129, aa 127-130, aa 128-131, aa 122-126, aa 123-127, aa 124-128, aa 125-129, aa 126-130, aa 127-131, aa 122-127, aa 123-128, aa 124-129, aa 125-130, aaa 126-131, aa 122-128, aa 123-129, aa 124-130, aa 125-131, aa 122-129, aa 123- 130
• the present invention preferably relates to the peptide aa 125-131 (SEQ LD 37), aa 125-128, aa 125-129 and aa 125-130.
• the present invention relates, with regard to the polypeptides comprising 4 to 11 aa derived from the sequence FAKYLWEWASVR (also referred to as "aa
• 158-169 (SEQ LD NO 35) as defined above, to peptides with the following aa sequence: aa 158- 161. aa 159-162, aa 160-163, aa 161-164, aa 162-165, aa 163-166, aa 164-167, aa 165-168, aa 166-169, aa 158-162, aa 159-163, a 160-164, aa 161-165, aa 162-166, aa 163-167, aa 164-168, aa 165-169, aaa 158-163, aa 159-164, aa 160-165, aa 161-166, aa 162-167, aa 163-168, aa 164- 169, aaa 158-164, aa 159-165, aa 160-166, aa 161-167, aa 162-168, aa 16
• the binding region to annexin V formed by the latter polypeptides might be a conformational binding region and should thus not be composed of a contiguous aa sequence.
• polypeptides as which comprise the sequences: KTCTTPAQGN (SEQ LD NO 2) or TTPAQGN (SEQ LD NO 37), and the sequence
• FAKYLWEWASVR SEQ LD 35. or functionally equivalent parts or variants of said sequences.
• the terms ''functionally equivalent parts or variants of said sequences refer to any variant or fragment ofthe peptides represented by SEQ LD 2, 35 and 37 which competes with the hepatitis surface antigen annexin V interaction or which binds a compound or antibody competing with the hepatitis B surface antigen/annexin V interaction.
• the latter terms do not specifically refer to, not do they exclude, post-translational modifications of the peptides such as glycosylation, acetylation. phosphorylation, modifications with fatty acids and the like.
• peptides containing one or more analogues of an aa including unnatural aa's
• peptides with substituted linkages peptides with substituted linkages
• mutated versions or natural sequence variations ofthe peptides corresponding to the genotypes of HBV
• peptides containing disulfide bounds between cysteine residues biotinylated peptides as well as other modifications known in the art.
• the present invention further relates to a polypeptide, as defined above, which, upon inoculation in a mammalian host, results in the production of antibodies which specifically bind to said polypeptide, in particular to one ofthe following sequences KTCTTPAQGN (SEQ LD NO 2) or parts thereof, or, TTPAQGN (SEQ LD 37) or parts thereof, or, FAKYLWEWASVR (SEQ ID NO 2)
• the present invention also relates to a combination of a polypeptide as defined above and a negatively charged phospholipid such as phosphatidylserine.
• a negatively charged phospholipid such as phosphatidylserine.
• the interaction between phosphatidylserine and A-V is demonstrated in the Examples section.
• the combination of said polypeptide and said negatively charged phospholipid component may be in any possible way known in the art such as for instance in the form of covalently or non-covalently coupled molecules or in the form of Iiposomes, etc.
• polypeptide composition refers to any possible mixture of above-described polypeptides with the same or with a different sequence or any possible linkage (covalently or otherwise) between above-described polypeptides with the same or with a different sequence.
• Examples ofthe latter polypeptide compositions are simple mixtures, homo -or hetero branched peptides, combinations of biotinylated peptides presented on streptavidin, avidin or neutravidin, chemically cross-linked peptides with or without spacer, condensing peptides and recombinantly produced peptides.
• the present invention also relates to a vaccine composition
• a vaccine composition comprising as an active substance a polypeptide as defined above which can be used as an inoculum to vaccinate humans against infection with HBV and or HDV or any mutated strain thereof or to therapeutically vaccinate human carriers of HBV and/or HDV or any mutated strain thereof.
• a vaccine composition relates to an immunogenic composition capable of eliciting protection against HBV and/or HDV, whether partial or complete.
• the term "as an active substance” relates to the component ofthe vaccine composition which elicits protection against HBVand/or HDV.
• An active substance ie. the polypeptides ofthe present invention
• An active substance can be used as such, in a biotinylated form (as explained in WO 93/18054) and/or complexed to Neutralite Avidin according to the manufacturer's instruction sheet (Molecular Probes Inc., Eugene, OR).
• a vaccine composition comprises, in addition to an active substance, a suitable excipient, diluent, carrier and/or adjuvant which, by themselves, do not induce the production of antibodies harmful to the individual receiving the composition nor do they elicit protection.
• Suitable carriers are typically large slowly metabolized macromolecules such as proteins, polysaccharides, polylactic acids, polyglycohc acids, polymeric aa's, aa copolymers and inactive virus particles. Such carriers are well known to those skilled in the art.
• Preferred adjuvants to enhance effectiveness ofthe composition include, but are not limited to: aluminium hydroxide, aluminium in combination with 3-0-deacylated monophosphoryl lipid A as described in WO 93/19780, aluminium phosphate as described in WO 93/24148, N-acetyl-muramyl-L- threonyl-D-isoglutamine as described in U.S.
• MPL + TDM + CWS cell wall skeleton
• a vaccine composition will further contain excipients and diluents, which are inherently non-toxic and non-therapeutic, such as water, saline, glycerol ethanol wetting or emulsifying agents, pH buffering substances, preservatives, and the like.
• a vaccine composition is prepared as an injectable, either as a liquid solution or suspension.
• Solid forms, suitable for solution on, or suspension in, liquid vehicles prior to injection may also be prepared.
• the preparation may also be emulsified or encapsulated in liposomes for enhancing adjuvant effect.
• the polypeptides may also be incorporated into Immune Stimulating Complexes together with saponins, for example Quil A (ISCOMS).
• Vaccine compositions comprise an immunologically effective amount of the polypeptides ofthe present invention, as well as any other ofthe above-mentioned components.
• Immunologically effective amount means that the administration of that amount to an kdrvidual either in a single dosis or as part of a series, is effective for prevention or treatment. This amount varies depending upon the health and physical condition of the individual to be treated, the taxonomic group of the mdividual to be treated (e.g. nonhuman primate, primate, etc.), the capacity ofthe individual's immune system to mount an effective immune response, the degree of protection desired, the formulation ofthe vaccine, the treating's doctor assessment, the strain of the infecting HBV, the co-infection status with HDV, and other relevant factors. It is expected that the amount will fall in a relatively broad range that can be determined through routine trials.
• the amount will vary from 0.01 to 1000 ⁇ g/dose, more particularly from 0.1 to 100 ⁇ g/dose.
• the vaccine compositions are conventionally administered parenterally, typically by injection, for example, subcutaneously or intramuscularly. Additional formulations suitable for other methods of administration include oral formulations and suppositories. Dosage treatment may be a single dose schedule or a multiple dose schedule.
• the vaccine may be administered in conjunction with other immunoregulatory agents. It should be noted that a vaccine may also be useful for treatment of an individual in which case it is called a "therapeutic vaccine".
• the present invention further relates to antibodies, or fragments thereof which specifically bind to a polypeptide as defined above and inhibit bmding of said polypeptide to annexin V.
• antibody refers to polyclonal or monoclonal antibodies.
• monoclonal antibody refers to an antibody composition having a homogeneous antibody population. The term is not limiting regarding the species or source ofthe antibody, nor is it intended to be limited by the manner in which it is made.
• the term “antibody” also refers to humanized antibodies in which at least a portion of the framework regions of an immunoglobulin are derived from human iirimunoglobulin sequences and single chain antibodies as described in U.S.
• fragments (of antibodies) refers to F ab , F, (ab)2 , F ⁇ and other fragments which retain the antigen binding function and specificity ofthe parent antibody.
• the inhibition of binding of said polypeptides to annexin V by these antibodies can be demonstrated in experiments which are similar to the ones described by Hertogs et al. (1993 and 1994).
• the present invention also relates to the usage of said antibodies as a medicament to treat humans infected with HBV and/or HDV or any mutated strain thereof.
• the term "medicament” refers to a composition comprising an antibody according to the present invention possibly in the presence of suitable exc ⁇ ients known to the skilled man such as saline, Ringer's solution, dextrose solution, Hank's solution, fixed oils, ethyl oleate, 5% dextrose in saline, substances that enhance isotonicity and chemical stability, buffers and preservatives.
• the "medicament” may be administered by any suitable method within the knowledge ofthe skilled man.
• the preferred route of administration is parenterally.
• the medicament of this invention will be formulated in a unit dosage injectable form such as a solution, suspension or emulsion, in association with the pharmaceutically acceptable excipients as defined above.
• the dosage and mode of administration will depend on the individual.
• the medicament is administered so that the antibody is given at a dose between 1 ⁇ g/kg and 10 mg/kg, more preferably between 10 ⁇ g/kg and 5 mg/kg, most preferably between 0.1 and 2 mg/kg.
• it is given as a bolus dose.
• Continuous infusion may also be used.
• the medicament may be infused at a dose between 5 and 20 ⁇ g/kg/minute, more preferably between 7 and 15 ⁇ g/kg/minute.
• the present invention further relates to the usage ofthe polypeptide as defined above for use in a method to detect antibodies which are capable of competing with the HBsAg/annexin V interaction and which are present in a biological sample, comprising:
• a method to detect refers to any immunoassay known in the art such as assays which utilize biotin and avidin or streptavidin, ELISA's and immunoprecipitation and agglutination assays. A detailed description of these assays is given in WO 96/13590.
• the present invention also relates to a diagnostic kit for the in vitro determination of antibodies to HBsAg containing: at least one microplate, polypeptides as defined above, appropriate buffer, blocking, and washing solutions which favor binding ofthe said polypeptides with the antibodies in human serum samples, and appropriate markers which allow to determine the complexes formed between the antibodies in human serum samples and said polypeptides.
• the present invention also relates to the usage of a polypeptide as defined above as a medicament to treat humans infected with HBV and/or HDV or any mutated strain thereof
• a medicament refers to a composition comprising a polypeptide according to the present invention possibly in the presence of suitable excipients known to the skilled man.
• suitable excipients, route of administration and dosage ofthe medicament are the same as described above for a medicament comprising an antibody.
• the present invention finally relates to the usage of a polypeptide as defined above for use in a method to screen for drugs which block the binding between annexin V and said polypeptide.
• a method to screen for drugs refers to any assay known in the art suitable for drug screening.
• the term refers to any immunoassay as described in WO 96/13590.
• drug may refer to any compound targetting or binding a polypeptide as defined above.
• Example 1 Transfection of the rat FTO2B cells with human annexin V
• HBV infectabihty of these cells was dete ⁇ nined by two replicative markers, namely by precore/core mRNA detection and by covalently closed circular (ccc) DNA detection.
• precore/core mRNA detection was investigated.
• Precore/core mRNA was detected in HBV infected ver tissue, but not in control hver tissue negative for HBV infection. It was also detected in HBV producing cells derived from the HBV-DNA transfected HepG2.2.15 cell line (Sells et al, 1987), while it was not detected in PLC/PRF/5 cells. These cells contain an integrated HBV genome and produce HBsAg. but no HBV infectious particles.
• the HBV inoculum used in further experiments contained no precore/core mRNA. but only HBV-DNA.
• RNA was indeed the template for amplification was confirmed by omission ofthe RT step or RNAse digestion before cDNA synthesis which resulted in failure of amplification.
• Ccc DNA was demonstrated in HBV infected ver tissue and in HBV-DNA transfected HepG2 cells, but not in inoculum.
• a rat hepatoma FTO2B cell line which is not infectable by HBV and does not express hA-V, was transduced with a construct containing the hA-V gene.
• One ofthe transduced cell lines is assigned as FTO9.1.
• Immunostaining and western blotting showed that the hA-V transfected rat hepatoma cell line FTO9.1 express hA-V, while the original non-transfected rat hepatoma cell line FTO2B does not express hA-V.
• the infectabihty of the FTO9.1 cell line was demonstrated by HBV precore/core mRNA detected as early as one day after infection, while non-transduced FTO2B cells were negative for HBV precore/core mRNA up to 7 days after infection so far investigated.
• ccc DNA was detected in FTO9.1 cells from 1 day up to 3 day after infection so far investigated.
• HBV-DNA which was not detectable in the culture medium before infection and in the first 2 days after infection, became detectable from day 3 until day 7 so far investigated.
• HBV-DNA was not detectable in culture medium of non-transduced FTO2B cells up to one week after infection.
• Example 2 The effect of anti-idiotypic antibodies (Ab2) on HBV infection in primary cultures of human hepatocytes.
• Human hepatocytes were isolated from human hver tissue obtained from post mortem donors by two-step collagenase perfusion method as described previously (Rijntjes et al., 1986). Cultured human hepatocytes were infected overnight at 37 °C by incubation with a 1/20 dilution of infectious human serum (HBV-DNA positive, HBsAg positive, HBeAg positive) followed by thorough washing. A sandwich ELISA using specific monoclonal antibodies was used both for capturing and detection of HBsAg.
• Figure 1 further indicates that the production of HBsAg was maximal at day 8 post infection. Thereafter, the HBsAg production declined due to deteriorated conditions ofthe primary culture of human hepatocytes as has also been seen in parallel control experiments.
• HBV replicative intermediates in the infected cells Since the presence of HBV replicative intermediates in the infected cells is an indispensable marker for successiveftil infection, total DNA is isolated from primary cultures of human hepatocytes used for these experiments and subjected for Southern blot analysis (Maniatis et al, 1982). As a control for the specificity ofthe probe, DNA isolated from the HepG2.2.15 cell line, as defined in Brief description of Figure 2, was also investigated. As shown in figure 2, HBV-DNA and replicative intermediates were detected in cells that were infected with inoculum in the absence of Ab2. In contrast, HBV-DNA sequences were not observed in experiments in which Ab2 were used.
• Example 3 Mapping of he annexin V-binding site on HBsAg
• HBsAg the region composed of aa 112 to 169 was investigated. Firstly, because this region has been predicted to be located on the outer surface of the virus; Secondly, because bmding of HBsAg with anti-idiotypic antibody Ab2 (generated in rabbits immunized with human Annexin V, Hertogs et al, 1994) is completely inhibited after digestion of HBsAg with endoproteinase-LysC. Lysines are only found in this region of t he HBsAg molecule (genotype A), namely at aa 122, at aa 141 and at aa 160. Three peptides covering this region were synthesized.
• the first two peptides represent the outer part ofthe HBsAg molecule. These peptides have been derived from a genotype C sequence.
• the third polypeptide represents the region ofthe outer part of HBsAg which is most subjected to non- conservative mutations. This peptide is derived from genotype A.
• polypeptide IGP673 (aa 112-141): GTGTTSTGPCKTCTIPAQGTSMFPSCCCTK (genotype C) polypeptide IGP671 (aa 139-169): CT PSDGNCTCIPIPSSWAFARFLWEGASVR
• polypeptide IGP80 (aa 122-157): KTCTTPAQGNSMEPSCCCTKPTDSNCTCIPIPSSWA (genotype A)
• the polypeptides 1077 and 1080 which are derived from genotype C, comprised a mutation (aa 107 from C to S) in order to reduce the number of cysteines in the peptide. Moreover, there are two aa within the region aa 99-136 which appear to mutate in a non-conservative way (eg. aa 126 from T to I and aa 131 from N to T) and which determine four of the naturally occuring genotypes of HBsAg (A, B, C and D, see table 1).
• this polypeptide (aa 125-134) is highly important since mutations within this region can alter or destroy binding with Ab2. Within the complete HBsAg molecule, however, these mutations do not destroy binding to annexin V since binding of annexin V and Ab2 to HBsAg of either genotypes A or D occurs (see figure 5) possibly because the complete molecule adopts a more rigid conformation which is not affected by mutations at positions 126 and 131. On the other hand, within a short polypeptide (20 aa) a single mutation may result in more drastic conformational changes which influences binding to annexin.
• variants and/or derivatives of said region which specifically bind human Annexin V may include any types of peptide variations discussed above.
• Example 4 Influence of phosphatidylserine on the HBsAg-annexin V binding
• CM1995 inhibits a protein-phospholipid interaction
• U4C8 inhibits a protein-protein interaction between human annexin V and HBsAg.
• the interaction of HBsAg with Ab2 is not influenced at all by phosphohpids of any kind.
• HBsAg-annexin V binding is based on at least a dual interaction. This includes binding of annexin V to negatively charged phosphohpids, such as phosphatidylserine, of the HBsAg particle via the phospholipid binding site of annexin V, and a second interaction which is based upon a protein to protein binding between a second distinct epitope of annexin V and the protein content ofthe HBsAg particle.
• Figure 10 gives an overview of this interaction.
• Example 5 Immunogenicity of the sequence aa 115-134.
• the annexin V binding domain of HBsAg was produced both as an N-terminally biotinylated polypeptide (IGP 1103), purified by RP-HPLC (96.6% purity), and as a tetrameric polypeptide on a lysine matrix which was biotinylated C-terminally (IGP 1119, see table 1).
• the sequence of peptide 1119 was further elongated with another 2 aa at the C-terminus in order to obtain a small linker between the lysine matrix and the sequence of interest.
• the latter peptide was purified by RP-HPLC in order to remove chemicals resulting fiom peptide synthesis.
• a Neutralite Avidin complex (Molecular Probes, Inc.. Eugene, OR) was made, -peptide 1103: 200 ⁇ g of peptide was mixed with 1.1 mg of Neutralite Avidin in a final volume of 2.5 ml saline. This solution was stored at -20°C as 500 ⁇ l ahquots for vaccine purposes.
• a control chimpanzee was also challenged with a standard inoculum for HBV. Serum samples were taken before and after inoculation and were screened for the presence of antibodies binding to HBsAg and to the peptides IGP 1103 and IGP 1119. The specificity of binding was verified using the same control peptides as indicated above (IGP 1030 and 1038). Although anti-HBsAg seroconversion could be clearly shown, no specific antibody reactivity against any ofthe peptides (IGP 1103, 1119, 1030 and 1038) could be demonstrated (Figure 13).
• the serum of a chimpanzee immunized with peptides 1103 and 1119 was evaluated for the presence of antibodies cross-reacting with the same region of HBsAg (aa 115-134) but derived from other genotypes.
• the antibody response evoked by the genotype A derived peptides 1119 and 1103 clearly cross-reacts with peptides carrying the non- conservative mutations from genotype B (IGP 1104), genotype C (IGP 1105) and genotype D (IGP 1104).
• genotype B genotype B
• genotype C genotype C
• genotype D genotype D
• Example 7 Direct binding of annexin V to HBsAg peptides representing the amino acid region 112-169.
• annexin V (coupled with horse radish peroxidase) to HBsAg itself or to biotinylated peptides coated to microtiterplates as a streptavidin complex was evaluated. These peptides represent the region 112-169 of HBsAg (IGP 671, 673 and 80), the peptide binding with the anti-idiotypic antibody (IGP 1119) as well as a control peptide (IGP 1038). Binding specificity is demonstrated by using an excess (100 ⁇ g/ml) of an anti- annexin V monoclonal antibody (U4C8, see example 4) which is known to compete with the binding of annexin V to HBsAg.
• U4C8 anti- annexin V monoclonal antibody
• TBS Ca/mg Tris buffered saline
• aspecific binding is reduced by blocking the plates with TBS Ca mg -3% gelatin at 37°C (fish gelatin).
• the incubation with annexin V and eventual competitors is performed in TBSc ⁇ -0.3% gelatin at 37°C. After incubation plates are washed with TBS Ca/mg -
• Example 9 Further fine mapping of the annexin V binding site on HBsAg by direct competition.
• Example 10 Further fine mapping of an Ab2 epitope.
• the peptides mentioned under example 3' (P461-P471) were further analyzed for their capacity to bind Ab2 using a different approach as used in example 3'.
• peptides were adsorbed to microtiterplates and the binding with Ab2 was evaluated. This may result in false negative scoring since not all of these peptides will adsorb equally well to the microtiteiplate.
• HBsAg itself is adsorbed to the microtiteiplate and the peptides are used in solution.
• Ab2 is allowed to bind to the peptides or HBsAg and finally binding of Ab2 to HBsAg itself is evaluated.
• Example 11 Further establishment of the role of region 115-126.
• Example 12 Mapping of other epitopes (monoclonal antibodies).
• Example 13 Further elaboration of the role of the region 158-169.
• the region 158-167 contains sufficient information to allow binding of annexin V: binding to peptides 1367 and 1362;
• the peptides 1119 and 1273 and 1274 were used for immunization of rabbits.
• the chimpanzee imiriunization (example 5) the peptides were complexed with Neutrahte avidin. Of each peptide three times 100 ⁇ g peptide complexed with an equimoiar amount of Neutrahte avidin was injected. In total six rabbits were used (2 rabbits for each peptide).
• the antibody responses were evaluated for cross-reactivity with HBsAg and were mapped using all available peptides from the previous examples.
• peptide 1119 the induced immune response was compared to the immune response induced in chimpanzee by a mixture of IGP 1103 and 1119
• any man skilled in the art may engineer such molecules using by way of example, but not limited to, peptides which are branched (homo- or hetero- (heterobranchrng can be performed by any sequence which is HBsAg derived or not), which are biotinylated (N-terminal with or without spacer, C-te ⁇ ninal with or without spacer) and complexed to avidin like molecules, which are covalently conjugated to non-related molecules (eg ovalbumin, hemocyanin), which are repeats of a single sequence, which are made cyclic (eg addition of cysteine at C- and N-terminus).
• peptides which are branched homo- or hetero- (heterobranchrng can be performed by any sequence which is HBsAg derived or not)
• biotinylated N-terminal with or without spacer, C-te ⁇ ninal with or without spacer
• avidin like molecules which are covalently conjugated to non-related molecules (eg
• Hepatitis delta virus attaches to human hepatocytes via human hver endonexin LI, a specific HbsAg binding protein. J. Viral Hepatitis 1: 33-38. Grundmann U, Abel K, Bohn H, Lobermann H, Lottspeich F, Kupper H (1988)
• IGP 1105 bio-TTSTGPCKTCTIPAQGTSMF (SEQ ID 19) IGP 1106 TTSTGPCKTCTTPAQGTSMF (SEQ ID 18) ⁇ m IGP 1107 TTSTGPCKTCTIPAQGTSMF (SEQ ID 19) IGP 1119 ( (TTSTGPCKTCTTPAQGNSMFPS) 2 K) 2 -KGK(bio)GA (SEQ ID 45) ⁇
• IGP 1030 (SVRVEQWKPPQK) 2 K) 2 -KGK(b ⁇ o)GA (SEQ ID 62) ,_, o
• IGP 1076 PVCP PGTSTTSTGPCKTCTIPAQGTSMFPS 12.9 ⁇ 3 IGP 1077 PVSPLLPGTSTTSTGPCKTCTIPAQGTSMFPS 0.4 IGP 1078 GTSTTSTGPCKTCTIPAQGTSMFPS 0.3 IGP 1079 GPCKTCTIPAQGTSMFPS 0.5 IGP 1081 DYQGMLPVCPLLPGTSTTSTGPCKTCTIPAQG 8.7 IGP 1080 DYQGM PVSPLLPGTSTTSTGPCKTCTIPAQG 0.9 IGP 1082 PLLPGTSTTSTGPCKTCTIPAQG 0.4 IGP 1083 GPCKTCTIPAQG 1.0

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