CN114685666A - Anti-mesothelin nano antibody and application thereof - Google Patents

Abstract

The present invention provides a mesothelin binding molecule comprising an anti-mesothelin single domain antibody having complementarity determining regions CDRs comprising CDR1 shown in SEQ ID No. 1, CDR2 shown in SEQ ID No. 2, and/or CDR3 shown in SEQ ID No. 3.

Description

Anti-mesothelin nano antibody and application thereof

Technical Field

The invention relates to the technical field of biomedicine or biopharmaceutical, in particular to a mesothelin binding molecule and application thereof.

Background

The Mesothelin (MSLN) gene is located on chromosome 1p13.3 and has a total length of 8 kD. The gene comprises 1884bp open reading frame, coding l7 exons and 628 amino acids. The precursor protein of MSLN is a glycoprotein of about 69kD length anchored to the cell membrane with a glycosylphosphopeptide inositol, which can be hydrolyzed by proteolytic enzymes into 2 parts, in which the N-terminus is 31kD soluble protein, having megakaryocyte stimulating activity, and is called megakaryocyte enhancing factor (MPF); while the C-terminus is a membrane bound protein of about 40kD in length, with cellular adhesion, called MSLN. The structure of MSLN in membrane proteins can be divided into three distinct segments, where region I is the binding site for ligand CA 125.

Mesothelin as a differentiation antigen is highly expressed in various malignant tumors and is closely related to the occurrence and development of the tumors, the target is one of the most potential anti-tumor targets, a plurality of large-scale drug enterprises aim at the target for development, and the current drug forms entering clinical tests comprise CAR-T, monoclonal antibodies, ADC and the like. Over the last 20 years, a variety of anti-mesothelin monoclonal antibodies have been developed, including primarily the SS1P immunotoxin and MORAB-009. SS1P is recombinant immunotoxin, is composed of scFv fused with truncated pseudoextracellular toxin, and mainly mediates cell killing; MORAB-009 is an IgG1 antibody recombined with the SS1P sequence, mainly causing antibody-dependent cell-mediated cytotoxicity (ADCC).

The nano antibody has the natural advantages of high stability, strong penetrating power and wide combined epitope (Muyledermans S.Annu Rev biochem.2013; 82:775-97.), develops a novel anti-mesothelin nano antibody, ensures that the novel anti-mesothelin nano antibody has better specificity, blocking activity and clinical efficacy, is simple and convenient to produce, has low cost, reduces the medication burden, and becomes a problem to be solved urgently.

Disclosure of Invention

The invention aims to provide a novel anti-mesothelin binding molecule and application thereof.

In a first aspect, the invention provides a mesothelin binding molecule comprising an anti-mesothelin single domain antibody whose complementarity determining regions CDRs comprise CDR1, CDR2 and CDR 3.

In one or more embodiments, the CDR1 includes the sequence set forth in SEQ ID No. 1.

In one or more embodiments, the CDR2 includes the sequence set forth in SEQ ID NO. 2.

In one or more embodiments, CDR3 includes the sequence set forth in SEQ ID NO. 3.

In one or more embodiments, the CDR1 comprises the sequence shown in SEQ ID NO. 1, the CDR2 comprises the sequence shown in SEQ ID NO. 2, and the CDR3 comprises the sequence shown in SEQ ID NO. 3.

In one or more embodiments, FR1 of the single domain antibody VHH can be selected from FR1 of any one of the VHHs of SEQ ID NOS 4-23, FR2 of a VHH can be selected from FR2 of any one of the VHHs of SEQ ID NOS 4-23, FR3 of a VHH can be selected from FR3 of any one of the VHHs of SEQ ID NOS 4-23, and FR4 of a VHH can be selected from FR4 of any one of the VHHs of SEQ ID NOS 4-23.

In one or more embodiments, the FR region of the single domain antibody is the FR region of any one of the VHHs selected from SEQ ID NOS 4-23.

In one or more embodiments, the single domain antibody VHH is as set forth in any one of SEQ ID NOS 4-23.

In one or more embodiments, the mesothelin-binding molecule is a monovalent or multivalent single domain antibody, multispecific single domain antibody, heavy chain antibody or antigen-binding fragment thereof, antibody or antigen-binding fragment thereof comprising one, two or more anti-mesothelin single domain antibodies described herein.

In one or more embodiments, the multivalent single domain antibody or multispecific single domain antibody is linked to a plurality of single domain antibodies by a linker. The linker consists of 1-15 amino acids selected from G and S.

In one or more embodiments, the antigen-binding fragment of the heavy chain antibody is a single chain heavy chain antibody.

In one or more embodiments, the heavy chain antibody is a camel heavy chain antibody or a cartilaginous fish heavy chain antibody.

In one or more embodiments, the heavy chain antibody further comprises a heavy chain constant region.

In one or more embodiments, the heavy chain constant region is a constant region of a camelid heavy chain antibody comprising CH2 and CH 3. In one or more embodiments, the CH2 and CH3 are CH2 and CH3 of human IgG Fc, e.g., CH2 and CH3 of IgG 4. Preferably, the heavy chain constant region is as set forth in SEQ ID NO 24.

In one or more embodiments, the heavy chain constant region is a constant region of a cartilaginous fish heavy chain antibody, comprising CH1, CH2, CH3, CH4, and CH 5.

In one or more embodiments, the antibody is an antibody comprising the anti-mesothelin single domain antibody as a heavy chain variable domain.

In one or more embodiments, the antibody further comprises a light chain variable domain, a heavy chain constant domain, and a light chain constant domain.

In one or more embodiments, the antigen-binding fragment of the antibody is selected from the group consisting of Fab, F (ab') 2, Fv, scFv.

In one or more embodiments, the binding molecule of any of the embodiments of the invention is a chimeric antibody or a fully human antibody; preferably fully human antibodies.

The invention also provides a polynucleotide selected from:

(1) a coding sequence of a single domain antibody according to any one of the embodiments herein or an antibody or antigen binding fragment thereof described herein;

(2) the complementary sequence of (1);

(3) a fragment of 5 to 50bp of any one of (1) or (2).

In one or more embodiments, the fragment is a primer.

The invention also provides a nucleic acid construct comprising a polynucleotide as described herein.

In one or more embodiments, the nucleic acid construct is a recombinant vector or an expression vector.

The invention also provides a bacteriophage comprising a mesothelin-binding molecule as described in any embodiment herein.

In one or more embodiments, the mesothelin-binding molecule is displayed on the phage surface.

The invention also provides a host cell selected from the group consisting of:

(1) expressing a mesothelin binding molecule according to any one of the embodiments herein;

(2) comprising a polynucleotide as described herein; and/or

(3) Comprising a nucleic acid construct as described herein.

The present invention also provides a method of producing a mesothelin-binding molecule comprising: culturing a host cell as described herein under conditions suitable for the production of a mesothelin-binding molecule (e.g., a monovalent or multivalent single domain antibody, multispecific single domain antibody, heavy chain antibody, or antigen-binding fragment thereof), and optionally purifying the mesothelin-binding molecule from the culture.

The present invention also provides a pharmaceutical composition comprising a mesothelin binding molecule, polynucleotide, nucleic acid construct, phage or host cell as described in any of the embodiments herein, and a pharmaceutically acceptable excipient.

In one or more embodiments, the pharmaceutical composition is for use in treating cancer.

In one or more embodiments, the cancer is a mesothelin-associated cancer. Preferably, the cancer comprises: mesothelioma, pancreatic cancer, ovarian cancer, lung adenocarcinoma, gastric cancer, and the like.

The invention also provides the use of a mesothelin binding molecule as described in any embodiment herein in the manufacture of a medicament for the prevention or treatment of cancer.

In one or more embodiments, the cancer is a mesothelin-associated cancer. Preferably, the cancer comprises: mesothelioma, pancreatic cancer, ovarian cancer, lung adenocarcinoma, gastric cancer, and the like.

The present invention also provides a method of treating or preventing cancer, the method comprising administering to a patient in need thereof a therapeutically effective amount of a mesothelin binding molecule according to any of the embodiments of the present invention, or a pharmaceutical composition comprising a mesothelin binding molecule according to any of the embodiments of the present invention.

In one or more embodiments, the cancer is a mesothelin-associated cancer. Preferably, the cancer comprises: mesothelioma, pancreatic cancer, ovarian cancer, lung adenocarcinoma, gastric cancer, and the like.

The present invention also provides a kit for detecting mesothelin for use in assessing the efficacy of a drug treatment or diagnosing cancer, said kit comprising a mesothelin binding molecule, polynucleotide, nucleic acid construct, phage or host cell as described in any of the embodiments herein.

In one or more embodiments, the kit further comprises reagents for detecting binding of mesothelin to the single domain antibody, antibody or antigen-binding fragment thereof. The bound reagent is detected, for example, by enzyme-linked immunosorbent assay.

In one or more embodiments, the agent that detects binding is a detectable label, such as biotin, that can be linked to a mesothelin binding molecule. The detectable label is attached to the mesothelin-binding molecule or is present separately in the kit.

The present invention also provides a non-diagnostic method for detecting the presence of mesothelin in a sample, said method comprising: incubating a sample with a mesothelin-binding molecule as described in any of the embodiments herein, and detecting binding of mesothelin to the single domain antibody, antibody or antigen-binding fragment thereof, thereby determining the presence of mesothelin in the sample. The detection is enzyme-linked immunosorbent assay detection.

The present invention also provides the use of a mesothelin-binding molecule as described in any of the embodiments herein in the preparation of a kit for detecting mesothelin in a sample, assessing the efficacy of a drug treatment or diagnosing cancer.

Drawings

Figure 1 is an alpaca antiserum titer test against MSLN protein.

FIG. 2 is an alpaca antiserum titer assay against MSLN overexpressing cell lines.

FIG. 3 shows the detection of the binding of candidate antibodies to MSLN protein overexpressing cell lines.

Detailed Description

The inventors of the present invention have extensively and intensively studied and found a class of mesothelin-binding molecules comprising anti-mesothelin single domain antibodies through a large number of screens, and the experimental results show that the binding molecules of the present invention are capable of specifically recognizing mesothelin, binding mesothelin or mesothelin-expressing cells and tumor cells with high affinity, and having no tissue cross-reaction. The single domain antibody of the invention is simple and convenient to generate.

Specifically, the invention utilizes human mesothelin protein to immunize alpaca to obtain a high-quality immune single domain antibody gene library. Then coupling the MSLN protein on an enzyme label plate, and screening an immune single-domain antibody gene library by utilizing a phage display technology, thereby obtaining the MSLN specific single-domain antibody gene. Then, the gene is transferred into mammalian cells, thereby obtaining a single domain antibody strain which can be efficiently expressed in the mammalian cells and has high specificity. Then, the high-affinity low-tissue cross-reactive single-domain antibody is identified by the methods of plasma resonance technology, flow cytometry and the like.

Antibodies

Herein, a "mesothelin-binding molecule" or "MSLN-binding molecule" is a protein that specifically binds mesothelin, including, but not limited to, antibodies, antigen-binding fragments of antibodies, heavy chain antibodies, nanobodies, minibodies, affibodies, target-binding regions of receptors, cell adhesion molecules, ligands, enzymes, cytokines, and chemokines.

Herein, the term "antibody" includes monoclonal antibodies (including full length antibodies having an immunoglobulin Fc region), antibody compositions having polyepitopic specificity, multispecific antibodies (e.g., bispecific antibodies), diabodies and single chain molecules, and antibody fragments, particularly antigen-binding fragments, e.g., Fab, F (ab') 2, and Fv. Herein, the terms "immunoglobulin" (Ig) and "antibody" are used interchangeably.

The basic 4-chain antibody unit is a heterotetrameric glycoprotein composed of two identical light chains (L) and two identical heavy chains (H). IgM antibodies consist of 5 basic heterotetrameric units and an additional polypeptide called the J chain, containing 10 antigen binding sites; while IgA antibodies comprise 2-5 basic 4 chain units, which can polymerize in combination with the J chain to form multivalent assemblies. In the case of IgG, the 4-chain unit is typically about 150,000 daltons. Each light chain is linked to a heavy chain by one covalent disulfide bond, while the two heavy chains are linked to each other by one or more disulfide bonds, the number of disulfide bonds depending on the isotype of the heavy chain. Each heavy and light chain also has regularly spaced intrachain disulfide bridges. Each heavy chain has a variable domain (VH) at the N-terminus, followed by three (CH1, CH2 and CH3 for each of the alpha and gamma chains) and four (CH1, CH2, CH3 and CH4 for the mu and epsilon isotypes) constant domains (CH) and a Hinge region (Hinge) located between the CH1 domain and the CH2 domain. Each light chain has a variable domain at the N-terminus (VL) followed by a constant domain at its other end (CL). VL is aligned with VH, while CL is aligned with the first constant domain of the heavy chain (CH 1). Specific amino acid residues are believed to form an interface between the light and heavy chain variable domains. The paired VH and VL together form an antigen binding site. For the structure and properties of different classes of antibodies see e.g. Basic and Clinical Immunology, eighth edition, Daniel p.sties, Abba i.terr and Tristram g.parsolw editions, Appleton & Lange, Norwalk, CT, 1994, page 71 and chapter 6. Light chains from any vertebrate species can be classified into one of two distinct types called kappa and lambda, depending on their constant domain amino acid sequences. Depending on its heavy chain constant domain (CH) amino acid sequence, immunoglobulins can be assigned to different classes or isotypes. There are five classes of immunoglobulins: IgA, IgD, IgE, IgG and IgM, have heavy chains called α, δ, ε, γ and μ, respectively. The γ and α classes can be further divided into subclasses based on the relatively small differences in CH sequence and function, for example humans express the following subclasses: IgG1, IgG2A, IgG2B, IgG3, IgG4, IgA1, and IgA 2.

As used herein, a "heavy chain antibody" is an antibody derived from a camelid or chondrocypristine organism. In contrast to the 4-chain antibody described above, the heavy chain antibody lacks the light and heavy chain constant region 1(CH1), and comprises only 2 heavy chains consisting of a variable region (VHH) linked to the constant region by a hinge-like structure and other constant regions. Each heavy chain of camelidae heavy chain antibodies comprises 1 variable region (VHH) and 2 constant regions (CH2 and CH3), and each heavy chain of chondrosarco heavy chain antibodies comprises 1 variable region and 5 constant regions (CH1-CH 5). Antigen-binding fragments of heavy chain antibodies include VHH and single chain heavy chain antibodies. Heavy chain antibodies may have CH2 and CH3 of human IgG Fc by fusion to the constant region of human IgG Fc.

As used herein, the terms "single domain antibody", "anti-mesothelin single domain antibody", "heavy chain variable region domain of heavy chain antibody", "VHH", "nanobody" are used interchangeably and all refer to single domain antibodies that specifically recognize and bind to mesothelin. Single domain antibodies are the variable regions of heavy chain antibodies. Typically, single domain antibodies contain three CDRs and four FRs. Preferably, the single domain antibody of the present invention has CDR1 shown in SEQ ID NO. 1, CDR2 shown in SEQ ID NO. 2, and CDR3 shown in SEQ ID NO. 3. Single domain antibodies are the smallest functional antigen-binding fragment. Typically, single domain antibodies consisting of only one heavy chain variable region are constructed by first obtaining an antibody that is naturally deficient in light and heavy chain constant region 1(CH1) and then cloning the variable region of the antibody heavy chain.

The binding molecule comprising two or more single domain antibodies is a multivalent single domain antibody; a binding molecule comprising two or more different specific single domain antibodies is a multispecific single domain antibody. A multivalent single domain antibody or multispecific single domain antibody is linked to multiple single domain antibodies by linkers. The linker typically consists of 1-15 amino acids selected from G and S.

Herein, heavy chain antibodies and antibodies are intended to distinguish different combinations of antibodies. Due to the structural similarity of the two, the following structural descriptions for antibodies apply to heavy chain antibodies as well as to light chains.

The "variable region" or "variable domain" of an antibody refers to the amino-terminal domain of the heavy or light chain of the antibody. The variable domains of the heavy and light chains may be referred to as "VH" and "VL", respectively. These domains are usually the most variable parts of an antibody (relative to other antibodies of the same type) and contain an antigen binding site.

The term "variable" refers to the situation where certain segments in the variable domains differ widely in antibody sequence. The variable domains mediate antigen binding and define the specificity of a particular antibody for its particular antigen. However, variability is not evenly distributed across all amino acids spanned by the variable domains. Instead, it is concentrated in three segments called hypervariable regions (HVRs), both in the light and heavy chain variable domains, namely HCDR1, HCDR2, HCDR3 (which may be abbreviated as CDR1, CDR2, CDR3 in heavy chain antibodies), respectively, of the heavy chain variable region, and LCDR1, LCDR2 and LCDR3 of the light chain variable region. The more highly conserved portions of the variable domains are called Framework Regions (FR). The variable domains of native heavy and light chains each comprise four FR regions (FR1, FR2, FR3 and FR4), which mostly adopt a β -sheet conformation, connected by three HVRs that form loops and, in some cases, form part of the β -sheet structure. The HVRs in each chain are held together in close proximity by the FR region and, together with the HVRs of the other chain, contribute to the formation of the antigen-binding site of the antibody. Generally, the light chain variable region has the structure FR1-LCDR1-FR2-LCDR2-FR3-LCDR3-FR4, and the heavy chain variable region has the structure FR1-HCDR1-FR2-HCDR2-FR3-HCDR3-FR 4. The constant domains are not directly involved in binding of the antibody to the antigen, but exhibit various effector functions, such as participation of the antibody in antibody-dependent cell-mediated cytotoxicity.

"Fc region" (crystallizable fragment region) or "Fc domain" or "Fc" refers to the C-terminal region of an antibody heavy chain that mediates binding of an immunoglobulin to host tissues or factors, including binding to Fc receptors located on various cells of the immune system (e.g., effector cells), or to the first component of the classical complement system (C1 q). In IgG, IgA and IgD antibody isotypes, the Fc region is composed of two identical protein fragments from the CH2 and CH3 domains of the two heavy chains of an antibody; the Fc region of IgM and IgE comprises three heavy chain constant domains (CH domains 2-4) in each polypeptide chain. Although the boundaries of the Fc region of an immunoglobulin heavy chain may vary, the human IgG heavy chain Fc region is generally defined as the stretch of sequence from the amino acid residue at heavy chain position C226 or P230 to the carboxy-terminus, where the numbering is according to the EU index, as in Kabat. As used herein, an Fc region can be a native sequence Fc or a variant Fc.

An "antibody fragment" comprises a portion of an intact antibody, preferably the antigen binding and/or variable regions of an intact antibody. The antibody fragment is preferably an antigen-binding fragment of an antibody. Examples of antibody fragments include Fab, Fab ', F (ab') 2, and Fv fragments; a diabody; a linear antibody; a single chain antibody molecule; a scFv-Fc fragment; multispecific antibodies formed from antibody fragments; and any fragment that should be able to increase half-life by chemical modification or by incorporation into liposomes. Digestion of an antibody with papain produces two identical antigen-binding fragments, called "Fab" fragments, and a residual "Fc" fragment, the name of which reflects its ability to crystallize readily. Fab fragments consist of the entire light and heavy chain variable domain (VH) and one heavy chain first constant domain (CH 1). Each Fab fragment is monovalent in terms of antigen binding, i.e., it has a single antigen binding site. Pepsin treatment of an antibody produces a larger F (ab') 2 fragment, roughly equivalent to two Fab fragments linked by disulfide bonds, with different antigen binding activity and still capable of crosslinking the antigen. Fab' fragments differ from Fab fragments by the addition of some additional residues at the carboxy terminus of the CH1 domain, including one or more cysteines from the antibody hinge region. F (ab ') 2 antibody fragments were originally generated as pairs of Fab ' fragments with hinge cysteines between the Fab ' fragments. Other chemical couplings of antibody fragments are also known. The Fc fragment comprises the carboxy-terminal portions of two heavy chains held together by disulfide bonds. The effector functions of antibodies are determined by sequences in the Fc region, which is also the region recognized by Fc receptors (fcrs) found on certain types of cells.

"Fv" is the smallest antibody fragment that contains the entire antigen recognition and binding site. The fragment consists of a dimer of one heavy chain variable domain and one light chain variable domain in tight, non-covalent association. Six hypervariable loops (3 loops each for the heavy and light chains) are highlighted from the folding of these two domains, contributing the amino acid residues for antigen binding and conferring antigen binding specificity to the antibody. However, even a single variable domain (or half of an Fv comprising only three HVRs specific for an antigen) has the ability to recognize and bind antigen, albeit with less avidity than the entire binding site. "Single-chain Fv" which may also be abbreviated as "sFv" or "scFv" is an antibody fragment comprising the VH and VL domains of an antibody, joined as a single polypeptide chain. Preferably, the sFv polypeptide further comprises a polypeptide linker between the VH and VL domains such that the sFv forms the desired antigen binding structure.

Herein, the term "monoclonal antibody" refers to an antibody obtained from a population of substantially homogeneous antibodies, i.e., the individual antibodies comprising the population are identical except for possible naturally occurring mutations and/or post-translational modifications (e.g., isomerization, amidation) that may be present in minor amounts. Monoclonal antibodies are highly specific, being directed against a single antigenic site. In contrast to polyclonal antibody preparations, which typically include different antibodies directed against different determinants (epitopes), each monoclonal antibody is directed against a single determinant on the antigen. In addition to their specificity, monoclonal antibodies are advantageous in that they are synthesized by hybridoma culture and are uncontaminated by other immunoglobulins. The modifier "monoclonal" indicates the character of the antibody as being obtained from a substantially homogeneous population of antibodies, and is not to be construed as requiring production of the antibody by any particular method. For example, monoclonal antibodies to be used in accordance with the present invention can be generated by a variety of techniques including, for example, hybridoma methods, phage display methods, recombinant DNA methods, and techniques for generating human or human-like antibodies from animals having part or all of a human immunoglobulin locus or genes encoding human immunoglobulin sequences, single cell sequencing methods.

Monoclonal antibodies also include "chimeric" antibodies herein 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 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, so long as they exhibit the desired biological activity.

"humanized" forms of non-human (e.g., murine) antibodies refer to chimeric antibodies that contain minimal sequences derived from non-human immunoglobulins. Thus, a "humanized antibody" generally refers to a non-human antibody in which the variable domain framework regions are exchanged with sequences found in a human antibody. Typically in humanized antibodies, the entire antibody (except for the CDRs) is encoded by a polynucleotide of human origin or is identical to such an antibody (except for the CDRs). CDRs, some or all of which are encoded by nucleic acids derived from non-human organisms, are grafted into the β -sheet framework of human antibody variable regions to produce antibodies, the specificity of which is determined by the grafted CDRs. Methods for producing such antibodies are well known in the art, e.g., using mice with genetically engineered immune systems. In the present invention, antibodies, single domain antibodies, heavy chain antibodies, etc., all include humanized variants of each of the antibodies.

"human antibody" refers to an antibody having an amino acid sequence corresponding to the amino acid sequence of an antibody produced by a human and/or produced using any of the techniques disclosed herein for producing human antibodies. This definition of human antibodies specifically excludes humanized antibodies comprising non-human antigen binding residues. Human antibodies can be generated using a variety of techniques known in the art, including phage display libraries.

In some embodiments, the invention also provides a single domain antibody, heavy chain antibody, antibody or antigen binding fragment thereof that binds to the same epitope of mesothelin as any anti-mesothelin single domain antibody of the invention, i.e., a single domain antibody, heavy chain antibody, antibody or antigen binding fragment thereof that is capable of cross-competing with any single domain antibody of the invention for binding to mesothelin.

In the present invention, CDR1 of the single domain antibody comprises the sequence shown in SEQ ID NO. 1.

In the present invention, CDR2 of the single domain antibody comprises the sequence shown in SEQ ID NO. 2.

In the present invention, CDR3 of the single domain antibody comprises the sequence shown in SEQ ID NO. 3.

In one or more embodiments, FR1 of the single domain antibody VHH may be selected from FR1, FR2 of VHH may be selected from FR2, FR3 of VHH may be selected from FR3, and FR4 of VHH may be selected from FR4 of VHH of each antibody number in table 1.

TABLE 1

Antibody numbering	VHH amino acid sequence
		M2339	SEQ ID NO:4
M2339-z11-1	SEQ ID NO:5
		M2339-z11-2	SEQ ID NO:6
M2339-z11-3	SEQ ID NO:7
		M2339-z11-4	SEQ ID NO:8
M2339-z11-5	SEQ ID NO:9
		M2339-z11-6	SEQ ID NO:10
M2339-z11-7	SEQ ID NO:11
		M2339-z11-8	SEQ ID NO:12
M2339-z11-9	SEQ ID NO:13
		M2339-z11-10	SEQ ID NO:14
M2339-z11-11	SEQ ID NO:15
		M2339-z11-12	SEQ ID NO:16
M2339-z11-13	SEQ ID NO:17
		M2339-z11-14	SEQ ID NO:18
M2339-z11-15	SEQ ID NO:19
		M2339-z11-16	SEQ ID NO:20
M2339-z11-17	SEQ ID NO:21
		M2339-z1-1	SEQ ID NO:22
M2339-z1-2	SEQ ID NO:23

In a preferred embodiment, the FR region of the VHH of the single domain antibody of the invention is the FR region of any one of the VHHs selected from SEQ ID NOS 4-23.

In one or more embodiments, the single domain antibody VHH is as set forth in any one of SEQ ID NOS 4-23.

The mesothelin-binding molecule described herein may be a monovalent or multivalent single domain antibody, multispecific single domain antibody, heavy chain antibody or antigen-binding fragment thereof, antibody or antigen-binding fragment thereof comprising one, two or more anti-mesothelin single domain antibodies described herein. The heavy chain antibody further comprises a heavy chain constant region, for example the constant region of a camel heavy chain antibody or a cartilaginous fish heavy chain antibody. Preferably, the heavy chain constant region is as set forth in SEQ ID NO 24.

The invention also includes derivatives and analogs of the antibodies. "derivatives" and "analogs" refer to polypeptides that retain substantially the same biological function or activity as the antibodies of the invention. The derivative or analogue of the invention may be (i) a polypeptide having a substituent group in one or more amino acid residues, or (ii) a polypeptide formed by fusing the mature polypeptide to another compound, such as a compound that increases the half-life of the polypeptide, for example polyethylene glycol, or (iii) a polypeptide formed by fusing an additional amino acid sequence to the sequence of the polypeptide (such as a leader or secretory sequence or a sequence used to purify the polypeptide or a proprotein sequence, or a fusion protein with a 6 His-tag). Such derivatives and analogs are within the purview of those skilled in the art in view of the teachings herein.

One skilled in the art can alter one or more (e.g., 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 or more) amino acids of the sequences of the invention to obtain variants of the sequences of the antibodies or functional fragments thereof without substantially affecting the activity of the antibodies. These variants include (but are not limited to): deletion, insertion and/or substitution of one or more (usually 1 to 50, preferably 1 to 30, more preferably 1 to 20, most preferably 1 to 10) amino acids, and addition of one or several (usually up to 20, preferably up to 10, more preferably up to 5) amino acids at the C-terminus and/or N-terminus. Conservative substitutions with amino acids of similar or similar properties are not known in the art to alter the function of the protein. Such as substituting amino acids having similar properties in the FR and/or CDR regions of the variable region. Amino acid residues that can be conservatively substituted are well known in the art. Such substituted amino acid residues may or may not be encoded by the genetic code. Also, for example, the addition of one or several amino acids at the C-terminus and/or N-terminus does not generally alter the function of the protein. All of which are considered to be included within the scope of the present invention.

Variants of the antibodies described herein include: homologous sequences, conservative variants, allelic variants, natural mutants, induced mutants, proteins encoded by DNA capable of hybridizing to DNA encoding the antibody of the present invention under high or low stringency conditions, and polypeptides or proteins obtained using antisera raised against the antibody of the present invention.

In some embodiments, the sequence of a variant of the invention may be at least 95%, 96%, 97%, 98% or 99% identical to the sequence from which it was derived. The sequence identity described in the present invention can be measured using sequence analysis software. For example the computer program BLAST, in particular BLASTP or TBLASTN, using default parameters. The invention also includes those molecules having the heavy chain variable region of an antibody with CDRs which are more than 90% (preferably more than 95%, most preferably more than 98%) homologous to the CDRs identified herein.

Antibodies of the invention can be prepared using methods conventional in the art, such as hybridoma technology, which is well known in the art. The heavy chain antibodies of the invention can be prepared using methods conventional in the art, such as phage display techniques well known in the art. Alternatively, the antibody or heavy chain antibody of the invention may be expressed in other cell lines. Suitable mammalian host cells can be transformed with sequences encoding the antibodies of the invention. Transformation can be carried out by any known method, including, for example, packaging the polynucleotide in a virus (or viral vector) and transducing the host cell with the virus (or vector). The transformation procedure used depends on the host to be transformed. Methods for introducing heterologous polynucleotides into mammalian cells are well known in the art and include dextran-mediated transfection, calcium phosphate precipitation, polybrene-mediated transfection, protoplast fusion, electroporation, encapsulation of polynucleotides in liposomes, and direct microinjection of DNA into the nucleus, among others. Mammalian cell lines useful as hosts for expression are well known in the art and include, but are not limited to, a variety of immortalized cell lines available from the American Type Culture Collection (ATCC), including, but not limited to, Chinese Hamster Ovary (CHO) cells, HeLa cells, Baby Hamster Kidney (BHK) cells, monkey kidney Cells (COS), human hepatocellular carcinoma cells (e.g., HepG2), and the like. Particularly preferred cell lines are selected by determining which cell lines have high expression levels and produce antibodies with substantial mesothelin binding properties.

Nucleic acids

The present invention also provides polynucleotides encoding the above antibodies or fragments thereof. Provided herein are polynucleotides encoding a heavy chain variable region, a light chain variable region, a heavy chain, a light chain, and each CDR. The polynucleotide of the present invention may be in the form of DNA or RNA. The form of DNA includes cDNA, genomic DNA or artificially synthesized DNA. The DNA may be single-stranded or double-stranded. The DNA may be the coding strand or the non-coding strand.

As will be appreciated by those skilled in the art, due to the degeneracy of the genetic code, a very large number of nucleic acids can be made, all of which encode an antibody or antigen-binding fragment thereof of the invention. Thus, where a particular amino acid sequence has been identified, one of skill in the art can make any number of different nucleic acids by simply modifying the sequence of one or more codons in a manner that does not alter the amino acid sequence encoding the protein. Thus, the present invention also relates to polynucleotides which hybridize to the above-described polynucleotide sequences and which have at least 50%, preferably at least 70%, and more preferably at least 80% identity between the two sequences. The present invention particularly relates to polynucleotides which hybridize under stringent conditions to the polynucleotides of the invention. In the present invention, "stringent conditions" mean: (1) hybridization and elution at lower ionic strength and higher temperature, such as 0.2 XSSC, 0.1% SDS,60 ℃; or (2) adding denaturant during hybridization, such as 50% (v/v) formamide, 0.1% calf serum/0.1% Ficoll, 42 deg.C, etc.; or (3) hybridization occurs only when the identity between two sequences is at least 90% or more, preferably 95% or more. Also, the polynucleotides that hybridize to the mature polypeptide encode polypeptides having the same biological functions and activities as the mature polypeptide.

The full-length nucleotide sequence of the antibody of the present invention or a fragment thereof can be obtained by a PCR amplification method, a recombinant method, or an artificial synthesis method. One possibility is to use synthetic methods to synthesize the sequence of interest, especially when the fragment length is short. Typically, long fragments are obtained by first synthesizing a plurality of small fragments and then ligating them together. Alternatively, the coding sequence for the heavy chain and an expression tag (e.g., 6His) can be fused together to form a fusion protein.

Once the sequence of interest has been obtained, it can be obtained in large quantities by recombinant methods. This is usually done by cloning it into a vector, transferring it into a cell, and isolating the relevant sequence from the propagated host cell by conventional methods. The biomolecules (nucleic acids, proteins, etc.) to which the present invention relates include biomolecules in an isolated form. At present, DNA sequences encoding the proteins of the present invention (or fragments or derivatives thereof) have been obtained completely by chemical synthesis. The DNA sequence may then be introduced into various existing DNA molecules (or vectors, for example) and cells known in the art. Furthermore, mutations can also be introduced into the protein sequences of the invention by chemical synthesis.

The invention therefore also relates to nucleic acid constructs, such as expression vectors and recombinant vectors, comprising suitable DNA sequences as described above and suitable promoter or control sequences. These vectors may be used to transform an appropriate host cell so that it can express the protein. Vectors typically contain sequences for plasmid maintenance and for cloning and expression of exogenous nucleotide sequences. The sequences (collectively referred to as "flanking sequences" in certain embodiments) typically include one or more of the following nucleotide sequences: a promoter, one or more enhancer sequences, an origin of replication, a transcription termination sequence, a complete intron sequence containing donor and acceptor splice sites, a sequence encoding a leader sequence for polypeptide secretion, a ribosome binding site, a polyadenylation sequence, a polylinker region for insertion of a nucleic acid encoding an antibody to be expressed, and a selectable marker element.

The host cell may be a prokaryotic cell, such as a bacterial cell; or lower eukaryotic cells, such as yeast cells; or higher eukaryotic cells, such as mammalian cells. Representative examples are: escherichia coli, streptomyces; bacterial cells of salmonella typhimurium; fungal cells such as yeast; insect cells of Drosophila S2 or Sf 9; CHO, COS7, 293 cells, etc.

In certain embodiments, the host cell can be a variety of functional cells known in the art, such as a variety of killer cells, including but not limited to cytokine-induced killer Cells (CIK), dendritic cell-stimulated cytokine-induced killer cells (DC-CIK), Cytotoxic T Lymphocytes (CTL), γ δ T cells, natural killer cells (NK), tumor-infiltrating lymphocytes (TIL), lymphokine-activated killer cells (LAK), CD3AK cells (anti-CD 3 mab-killed cells), and CAR-T/TCR-T cells. In certain embodiments, the killer cell is a T cell or an NK cell. Exemplary NK cells include, but are not limited to, primary NK cells, NK cell lines (e.g., NK92), and NKT cells. In certain embodiments, the NK cell is a primary NK cell. Exemplary T cells include, but are not limited to, T cells from mixed cell populations such as peripheral blood T lymphocytes, cytotoxic T Cells (CTLs), helper T cells, suppressor/regulatory T cells, γ δ T cells, and cytokine-induced killer Cells (CIKs), tumor-infiltrating lymphocytes (TILs), and the like. In certain embodiments, the T cells are peripheral blood T lymphocytes and TIL-derived T cells.

Transformation of a host cell with recombinant DNA may be carried out using conventional techniques well known to those skilled in the art. When the host is prokaryotic, e.g., E.coli, competent cells capable of DNA uptake can be harvested after exponential growth phase using CaCl₂Methods, the steps used are well known in the art. Another method is to use MgCl₂. If desired, transformation can also be carried out by electroporation. When the host is a eukaryote, the following DNA transfection methods may be used: calcium phosphate coprecipitation, conventional mechanical methods such as microinjection, electroporation, liposome encapsulation, and the like.

The obtained transformant can be cultured by a conventional method to express the polypeptide encoded by the gene of the present invention. The medium used in the culture may be selected from various conventional media depending on the host cell used. The culturing is performed under conditions suitable for growth of the host cell. After the host cells have been grown to an appropriate cell density, the selected promoter is induced by suitable means (e.g., temperature shift or chemical induction) and the cells are cultured for an additional period of time.

The polypeptide in the above method may be expressed intracellularly or on the cell membrane, or secreted extracellularly. If necessary, the recombinant protein can be isolated and purified by various separation methods using its physical, chemical and other properties. These methods are well known to those skilled in the art. Examples of such methods include, but are not limited to: conventional renaturation treatment, treatment with a protein precipitant (such as salt precipitation), centrifugation, cell lysis by osmosis, sonication, ultracentrifugation, molecular sieve chromatography (gel filtration), adsorption chromatography, ion exchange chromatography, High Performance Liquid Chromatography (HPLC), and other various liquid chromatography techniques, and combinations thereof.

Therapeutic uses and pharmaceutical compositions

By constructing a nanobody library, the inventors found and expressed 1 purified nanobody capable of binding to MSLN protein, and humanized it, obtaining a series of humanized nanobodies. The binding ability of these antibodies to antigens and cells and drug safety were verified by protein level affinity assay, cell level affinity assay, tissue cross-reaction.

Accordingly, all aspects of the antibodies described herein are useful in the preparation of medicaments for the prevention or treatment of various conditions and diseases described herein, particularly diseases or conditions in which the condition is associated with cells expressing mesothelin. In some embodiments, the conditions and diseases are cancers, including but not limited to: mesothelioma, pancreatic cancer, ovarian cancer, lung adenocarcinoma, gastric cancer, and the like.

The pharmaceutical compositions herein contain a binding molecule as described herein, and pharmaceutically acceptable excipients including, but not limited to, diluents, carriers, solubilizers, emulsifiers, preservatives and/or adjuvants. Adjuvants are preferably non-toxic to recipients at the dosages and concentrations employed. Such adjuvants include (but are not limited to): saline, buffer, glucose, water, glycerol, ethanol, and combinations thereof. In certain embodiments, the pharmaceutical composition may contain a substance for improving, maintaining or retaining, for example, the pH, osmolarity, viscosity, clarity, color, isotonicity, odor, sterility, stability, dissolution or release rate, absorption or permeation of the composition. These substances are known from the prior art. The optimal pharmaceutical composition can be determined depending on the intended route of administration, mode of delivery and the desired dosage.

Pharmaceutical compositions for in vivo administration are generally provided in the form of sterile preparations. Sterilization is achieved by filtration through sterile filtration membranes. In the case of lyophilization of the composition, sterilization can be performed using this method either before or after lyophilization and reconstitution. The pharmaceutical compositions of the present invention may be selected for parenteral delivery. Compositions for parenteral administration may be stored in lyophilized form or in solution. For example, by a conventional method using physiological saline or an aqueous solution containing glucose and other adjuvants. Parenteral compositions are typically placed in a container having a sterile access port, such as an intravenous solution strip or vial having a stopper pierceable by a hypodermic injection needle. Alternatively, the composition may be selected for inhalation or for delivery through the alimentary canal (such as orally). The preparation of such pharmaceutically acceptable compositions is within the skill of the art. Other pharmaceutical compositions will be apparent to those skilled in the art, including formulations comprising the antibody in sustained or controlled release delivery formulations. Techniques for formulating a variety of other sustained or controlled delivery means, such as liposome carriers, bioerodible microparticles or porous beads, and depot injections, are also known to those skilled in the art.

Once formulated, the pharmaceutical compositions are stored in sterile vials as solutions, suspensions, gels, emulsions, solids, crystals, or as dehydrated or lyophilized powders. The formulation may be stored in a ready-to-use form or reconstituted prior to administration (e.g., lyophilized). The invention also provides kits for producing a single dose administration unit. The kits of the invention may each contain a first container having a dried protein and a second container having an aqueous formulation. In certain embodiments of the invention, kits are provided that contain single and multi-chamber pre-filled syringes (e.g., liquid syringes and lyophilized syringes).

The invention also provides a method of treating a patient, in particular a mesothelin-related disease in a patient, by administering a binding molecule according to any of the embodiments of the invention or a pharmaceutical composition thereof. Herein, the terms "patient," "subject," "individual," "subject" are used interchangeably herein and include any organism, preferably an animal, more preferably a mammal (e.g., rat, mouse, dog, cat, rabbit, etc.), and most preferably a human. "treatment" refers to the subject taking a treatment regimen described herein to achieve at least one positive therapeutic effect (e.g., a decrease in the number of cancer cells, a decrease in tumor volume, a decrease in the rate of cancer cell infiltration into peripheral organs, or a decrease in the rate of tumor metastasis or tumor growth). The treatment regimen effective to treat a patient may vary depending on a variety of factors, such as the disease state, age, weight of the patient, and the ability of the therapy to elicit an anti-cancer response in the subject.

The therapeutically effective amount of a pharmaceutical composition comprising a binding molecule of the invention to be employed will depend, for example, on the degree of treatment and the goal. One skilled in the art will appreciate that the appropriate dosage level for treatment will vary depending, in part, on the molecule delivered, the indication, the route of administration, and the size (body weight, body surface or organ size) and/or condition (age and general health) of the patient. In certain embodiments, the clinician may titrate the dosage and alter the route of administration to achieve optimal therapeutic effect. For example, from about 10 micrograms per kilogram of body weight to about 50 milligrams per kilogram of body weight per day.

The frequency of administration will depend on the pharmacokinetic parameters of the binding molecule in the formulation used. The clinician typically administers the composition until a dosage is reached that achieves the desired effect. The compositions may thus be administered as a single dose, or over time as two or more doses (which may or may not contain the same amount of the desired molecule), or by continuous infusion through an implanted device or catheter.

The route of administration of the pharmaceutical composition is according to known methods, e.g., oral, by intravenous, intraperitoneal, intracerebral (intraparenchymal), intracerebroventricular, intramuscular, intraocular, intraarterial, portal vein or intralesional injection; by a sustained release system or by an implanted device.

Diagnostics, assays and kits

The binding molecules of the invention are useful in assays, e.g., binding assays, for detecting and/or quantifying mesothelin expressed in a tissue or cell due to its high affinity for mesothelin. Binding molecules such as single domain antibodies can be used in studies to further investigate the role of mesothelin in disease. The method for detecting mesothelin is generally as follows: obtaining a cell and/or tissue sample; the level of mesothelin in the sample is detected.

The mesothelin binding molecules of the present invention may be used for diagnostic purposes to detect, diagnose or monitor mesothelin-associated diseases and/or conditions. The present invention provides for the detection of the presence of mesothelin in a sample using classical immunohistological methods known to those skilled in the art. The detection of mesothelin may be performed in vivo or in vitro. Examples of methods suitable for detecting the presence of mesothelin include ELISA, FACS, RIA, and the like.

For diagnostic applications, the binding molecules, such as single domain antibodies, are typically labeled with a detectable labeling group. Suitable labeling groups include (but are not limited to) the following: radioisotopes or radionuclides (e.g., 3H, 14C, 15N, 35S, 90Y, 99Tc, 111In, 125I, 131I), fluorescent groups (e.g., FITC, rhodamine, lanthanide phosphors), enzymatic groups (e.g., horseradish peroxidase, beta-galactosidase, luciferase, alkaline phosphatase), chemiluminescent groups, biotin groups, or predetermined polypeptide epitopes recognized by secondary reporters (e.g., leucine zipper pair sequences, binding sites for secondary antibodies, metal binding domains, epitope tags), MRI (magnetic resonance imaging), or CT (computed tomography) contrast agents. Various methods for labeling proteins are known in the art and can be used to carry out the present invention.

Another aspect of the invention provides a method of detecting the presence of a test molecule that competes with an antibody of the invention for binding to mesothelin. One example of such an assay would involve detecting the amount of free antibody in a solution containing an amount of mesothelin, in the presence or absence of a test molecule. An increase in the amount of free antibody (i.e., antibody that does not bind mesothelin) would indicate that the test molecule is able to compete with the antibody for binding mesothelin. In one embodiment, the antibody is labeled with a labeling group. Alternatively, the test molecule is labeled and the amount of free test molecule is monitored in the presence or absence of antibody.

The invention also provides a detection kit for detecting the mesothelin level, which comprises an antibody for identifying mesothelin protein, a lysis medium for dissolving a sample, and general reagents and buffers required for detection, such as various buffers, detection markers, detection substrates and the like. The test kit may be an in vitro diagnostic device.

The present invention will be illustrated below by way of specific examples. It should be understood that these examples are illustrative only and are not intended to limit the scope of the present invention. The methods and materials used in the examples are, unless otherwise indicated, all those materials and methods conventional in the art.

Examples

Example 1 alpaca immunization

1.1 immunogen preparation:

inquiring the sequence of the mesothelin protein according to NCBI, fusing the sequence with the sequence of the human IgG Fc fragment, entrusting Nanjing Kingsry company to synthesize and construct a eukaryotic expression vector of pCDNA3.4(Thermo) plasmid, and utilizing ExpicCHO to synthesize the synthesized plasmid^TM(Thermo Fisher) expression system, performing one-step affinity purification by using 5mL Protein A pre-packed column (GE) after expression, replacing the purified sample in PBS buffer solution, identifying purity by SDS-PAGE electrophoresis gel and HPLC, and performing ELISA activity identification, and subpackaging and freezing in a refrigerator of-80 ℃ for subsequent immunization.

1.2 alpaca immunization:

the first immune antigen (MSLN. hFc) amount is 400 μ g, and is mixed with adjuvant (GERBU FAMA) uniformly, and four-point subcutaneous injection immunization is selected for alpaca back, and the immunization amount per point is 1 mL. Second to sixth immunizations: the immune antigen amount is 200 mug, four subcutaneous points on the back of the alpaca are selected for immunization, and the immunization amount per point is 1 mL. The time interval between each immunization was one week.

1.3 immune serum titer detection:

1.3.1 protein level titer assay

Coating MSLN.His antigen at 4 ℃ overnight, sealing and washing, adding the serum diluted in gradient into an ELISA plate for incubation, then using anti-llama (anti-alpaca) IgG HRP (Abcam) antibody for incubation, adding TMB color development liquid for color development after washing, stopping reaction by using 2M HCl, and then detecting the light absorption value at OD450 nm by using a microplate reader. The experimental results are shown in figure 1, and the alpaca titer reaches a higher level (>243000) after 6 immunizations.

1.3.2 cell level titer detection

MSLN transfected HEK293T cells in a number of 3X 10 plated in 96 well plates⁵Cells/well. The cells were then incubated with serum diluted in a 3-fold gradient. After incubation, washing, incubation with anti-llama IgG PE (Jackson) antibody, washing, resuspending the cells in PBS, and then detecting the fluorescence intensity (MFI) with a flow cytometer (Beckman). The results are shown in FIG. 2.

Example 2 construction and screening of Nanobody immune libraries against MSLN

(1) After 6 times of immunization, 100mL of camel peripheral blood lymphocytes are extracted, and total RNA is extracted. RNA extraction was performed according to TAKARA RNAiso reagent instructions.

(2) First strand cDNA was synthesized using RNA as a template and oligo dT as a primer, according to the reverse transcriptase instruction of TAKARA.

(3) The variable region coding gene of the heavy chain antibody is obtained by nested PCR by using PrimeSTAR high-fidelity DNA polymerase. Variable region fragments of heavy chain antibodies were amplified by nested PCR:

first round PCR:

an upstream primer: gtcctggctgctcttctacaaggc (SEQ ID NO:25)

A downstream primer: ggtacgtgctgttgaactgttcc (SEQ ID NO:26)

Amplifying the fragment between the heavy chain antibody leader peptide and antibody CH2, annealing at 55 ℃ for 30 cycles; a DNA fragment of about 600bp was recovered as a template for the second round of PCR.

Second round PCR:

an upstream primer: gatgtgcagctgcaggaggtctgggrggaggg (SEQ ID NO:27)

A downstream primer: ggactagtgcggccgctggagacggtgacctgggt (SEQ ID NO:28)

The fragments (long fragment and short fragment) between the FR1 region and the long and short hinge regions of the heavy chain antibody were amplified, annealed at 55 ℃ for 30 cycles, and the desired fragment was recovered, and as a result, it was revealed that the size of the fragment was about 500bp, i.e., the gene electrophoresis band of the nanobody was about 500 bp.

(4) The phagemid pME207 and the PCR amplification product were digested simultaneously with Sfi I and Not I (NEB), recovered and quantified, and then the two fragments were ligated with T4 DNA ligase (TaKaRa) at a molar ratio of 1: 3, and ligated at 16 ℃ overnight.

(5) After the ligation product was precipitated with ethanol, it was dissolved in 100. mu.L of sterile water and transformed into E.coli TG1 by electroporation ten times. Diluting the cultured bacterial liquid by 100 mu L of electric shock in a multiple ratio, coating an ampicillin LB culture plate, calculating the storage capacity, coating the rest part of the culture medium on an ampicillin 2 XYT culture plate, and performing inverted culture at 37 ℃ for 13-16 h. After scraping the lawn on the plate with 10mL of 2 XYT medium, glycerol was added to the final concentration of 25%, and the plate was aliquoted and stored at-80 ℃ for further use. The size of the storage capacity is 4.3 × 10⁹. In order to detect the insertion rate of the library, 48 clones are randomly selected for colony PCR, and the result shows that the insertion rate reaches over 90 percent.

(6) According to the calculated library volume results, 10 times of the library volume of viable cells were inoculated into 200mL of 2 XYT (containing 2% glucose, 100. mu.g/mL ampicillin), cultured at 37 ℃ at 200r/min until OD600 reached 0.5, helper phage was added at a multiplicity of infection of 20: 1, and after standing at 37 ℃ for 30min, at 37 ℃ at 200r/min for 30 min. Centrifuging the culture, resuspending and precipitating with 200mL of 2 XYT (containing 100. mu.g/mL ampicillin and 50. mu.g/mL kanamycin), culturing overnight at 37 ℃ at 250r/min, then centrifuging at 8000rpm, taking the supernatant, adding 5 XPEG/NaCl solution, standing on ice for 60min, centrifuging at 8000rpm for 30min, resuspending and precipitating in 5mL of PBS to obtain the single-domain heavy chain antibody (VHH) immune library of anti-MSLN, taking 10. mu.L of the antibody titer, and storing the rest at-80 ℃ for later use.

(7) Coating MSLN. hFc on enzyme label plate at 10 ug/mL, 100 ul per well, and standing at 4 degreeOvernight, while a negative control was set up. The next day, 200. mu.L of 3% BSA was added to each of the five wells and blocked for 2 hours at room temperature. After 2 hours, wash 3 times with PBST (0.05% Tween 20 in PBS). After washing the plate, 100. mu.L of phage (2-3X 10) pre-sealed with 5% skimmed milk is added into each negative sieve pore¹¹tfu immune camel nanometer antibody phage display gene bank), acting for 1.5 hours at room temperature, transferring the supernatant after negative screening to the target antigen coating hole, and acting for 1.5 hours at room temperature. Wash 12 times with PBST (0.05% Tween 20 in PBS) to wash away unbound phage. Phages specifically bound to MSLN were dissociated with glycine (sigma), and eluted phages were Tris (Invitrogen, 1M, PH 8.0) neutralized to infect TG 1in log phase, propagated and amplified for the next round of "adsorption-elution". Finally, the eluted phage is impregnated with TG1, IPTG 1 is induced by IPTG (thermo) to express a nano antibody, an ELISA plate is coated by MSLN>Clones of 0.5 were sequenced.

(8) After sequence analysis, 1 clone that could bind to the MSLN. His protein (MSN-H5223, Ohio Hizikia science and technology Co., Ltd.) was obtained as shown in the following table. The amino acid sequence of the negative control is shown as SEQ ID NO. 2 in CN 106046152A.

Example 3 purification of candidate antibody expression

The nano antibody is constructed on a pCDNA3.4-IgG4 carrier and then is processed by ExpicHO^TM(Thermo Fisher) expression system, and after one week of expression, the supernatant was collected for Protein A (GE) purification. Then, the mass concentration of the protein is detected by using Nanodrop, and the purity of the protein is detected by HPLC. The purity and the yield of the obtained protein meet the requirements of subsequent experiments.

Example 4 candidate antibody characterization

(1) Protein level affinity assay: the binding kinetics and affinity of antibodies to human msln. Purified antibody was passed through a sensor chip on which protein a was previously immobilized, and the antibody was captured by protein a, and then 5 different concentrations of msln. The association rate (ka), dissociation rate (KD), and equilibrium constant (KD) were analyzed using Biacore Evaluation Software 2.0 (GE). The results are shown in the following table.

Antibody numbering	ka(1/Ms)	kd(1/s)	KD(M)
				M2339	6.90E+04	1.82E-05	2.64E-10

(2) Cell level affinity assay: MSLN-expressing HEK293T cells were plated in 96-well plates at 3X 10 per well⁵The cells were then incubated with HEK293T MSLN cells with a gradient of diluted heavy chain antibody for half an hour, then incubated with a detection secondary anti-human IgG PE (Jackson Immuno Research, Code: 109-. The results are shown in FIG. 3. The EC50 for the antibody was calculated by fitting a curve to be 3.682 nM. Isotype is an Isotype control (negative control), and the amino acid sequence of Isotype is shown as SEQ ID No. 2 in CN 106046152A.

Example 5 antibody humanization

M2339 was humanized using a CDR region grafting method, with reference to a method of humanizing nanobodies (J.biol.chem.2009; 284: 3273-3284). The IgBLAST (http:// www.ncbi.nlm.nih.gov/IgBLAST /) database was screened for the lines with higher homology to M2339 (germline) as templates. The humanized nanobodies shown in the following table were obtained. Using Biacore to carry out affinity detection on antibodies before and after humanization, enabling the purified antibodies to flow through a sensor chip on which protein A is fixed in advance, capturing the antibodies by the protein A, and then taking MSLN.His proteins with 5 different concentrations as mobile phases, wherein the binding time and the dissociation time are respectively 30min and 60 min. The association rate (ka), dissociation rate (KD), and equilibrium constant (KD) were analyzed using Biacore Evaluation Software 2.0 (GE).

Example 6 tissue Cross-reactivity

The tissue cross reaction is carried out on M2339-z11-2 by the following specific operations: selecting 34 tissues to be frozen sections, drying the frozen sections at normal temperature, and fixing the frozen sections by using acetone. Blocking was performed using reagent a and reagent B of the endogenous biotin blocking kit (manufacturer, E674001). The biotin-labeled antibody samples were incubated for 30min, washed and incubated for 15min with horseradish peroxidase-labeled streptavidin (Abcam, ab 7403). DAB color development and hematoxylin counterstaining are used, the neutral plastic is sealed, and microscopic examination is carried out after natural air drying. The positive control was Anti-Mesothelin antibody (Biotin) (ab271813) and the negative control was a Biotin-labeled IgG4 isotype control. The results are shown in the following table.

Sequence listing

<110> Zhejiang Nanobody technology center, Ltd

<120> anti-mesothelin nano antibody and application thereof

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Ile Ser Gly Thr Gly Gly Ile Thr

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Ala Ala Asp Glu Arg Cys Thr Asp Arg Leu Ile Arg Pro Pro Thr Tyr

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Asp Ser Val Lys Gly Arg Phe Thr Ile Ser Arg Asp Ile Ala Lys Thr

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Tyr Tyr Cys Ala Ala Asp Glu Arg Cys Thr Asp Arg Leu Ile Arg Pro

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Pro Thr Tyr Trp Gly Gln Gly Thr Gln Val Thr Val Ser Ser

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Asp Ser Val Lys Gly Arg Phe Thr Ile Ser Arg Asp Asn Ser Lys Thr

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Pro Thr Tyr Trp Gly Gln Gly Thr Gln Val Thr Val Ser Ser

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Pro Thr Tyr Trp Gly Gln Gly Thr Gln Val Thr Val Ser Ser

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Thr Val Tyr Leu Gln Met Asn Ser Leu Arg Ala Glu Asp Thr Ala Val

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Pro Thr Tyr Trp Gly Gln Gly Thr Gln Val Thr Val Ser Ser

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Glu Gly Val Ser Cys Ile Ser Gly Thr Gly Gly Ile Thr His Tyr Ala

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Thr Val Tyr Leu Gln Met Asn Ser Leu Arg Ala Glu Asp Thr Ala Val

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Tyr Tyr Cys Ala Ala Asp Glu Arg Cys Thr Asp Arg Leu Ile Arg Pro

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Pro Thr Tyr Trp Gly Gln Gly Thr Gln Val Thr Val Ser Ser

115 120 125

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Glu Val Gln Leu Val Ala Ser Gly Gly Gly Leu Val Gln Pro Gly Gly

1 5 10 15

Ser Leu Arg Leu Ser Cys Ala Leu Ser Gly Phe Thr Leu Arg Glu Leu

20 25 30

Asp Glu Phe Ala Ile Gly Trp Phe Arg Gln Ala Pro Gly Lys Glu Arg

35 40 45

Glu Gly Val Ser Cys Ile Ser Gly Thr Gly Gly Ile Thr His Tyr Ala

50 55 60

Asp Ser Val Lys Gly Arg Phe Thr Ile Ser Arg Asp Asn Ser Lys Thr

65 70 75 80

Thr Val Tyr Leu Gln Met Asn Ser Leu Asn Ala Glu Asp Thr Ala Val

85 90 95

Tyr Tyr Cys Ala Ala Asp Glu Arg Cys Thr Asp Arg Leu Ile Arg Pro

100 105 110

Pro Thr Tyr Trp Gly Gln Gly Thr Gln Val Thr Val Ser Ser

115 120 125

<210> 10

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Glu Val Gln Leu Val Ala Ser Gly Gly Gly Leu Val Gln Pro Gly Gly

1 5 10 15

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20 25 30

Asp Glu Phe Ala Ile Gly Trp Phe Arg Gln Ala Pro Gly Lys Glu Arg

35 40 45

Glu Gly Val Ser Cys Ile Ser Gly Thr Gly Gly Ile Thr His Tyr Ala

50 55 60

Asp Ser Val Lys Gly Arg Phe Thr Ile Ser Arg Asp Asn Ser Lys Thr

65 70 75 80

Thr Val Tyr Leu Gln Met Asn Ser Leu Arg Ser Glu Asp Thr Ala Val

85 90 95

Tyr Tyr Cys Ala Ala Asp Glu Arg Cys Thr Asp Arg Leu Ile Arg Pro

100 105 110

Pro Thr Tyr Trp Gly Gln Gly Thr Gln Val Thr Val Ser Ser

115 120 125

<210> 11

<211> 126

<212> PRT

<213> Artificial Sequence

<400> 11

Glu Leu Gln Leu Gly Ala Ser Gly Gly Gly Leu Val Gln Pro Gly Gly

1 5 10 15

Ser Leu Arg Leu Ser Cys Ala Leu Ser Gly Phe Thr Leu Arg Glu Leu

20 25 30

Asp Glu Phe Ala Ile Gly Trp Phe Arg Gln Ala Pro Gly Lys Glu Arg

35 40 45

Glu Gly Val Ser Cys Ile Ser Gly Thr Gly Gly Ile Thr His Tyr Ala

50 55 60

Asp Ser Val Lys Gly Arg Phe Thr Ile Ser Arg Asp Asn Ser Lys Thr

65 70 75 80

Thr Val Tyr Leu Gln Met Asn Ser Leu Arg Ala Glu Asp Thr Ala Val

85 90 95

Tyr Tyr Cys Ala Ala Asp Glu Arg Cys Thr Asp Arg Leu Ile Arg Pro

100 105 110

Pro Thr Tyr Trp Gly Gln Gly Thr Gln Val Thr Val Ser Ser

115 120 125

<210> 12

<211> 126

<212> PRT

<213> Artificial Sequence

<400> 12

Gln Leu Gln Leu Gly Glu Ser Gly Gly Gly Leu Val Gln Pro Gly Gly

1 5 10 15

Ser Leu Arg Leu Ser Cys Ala Leu Ser Gly Phe Thr Leu Arg Glu Leu

20 25 30

Asp Glu Phe Ala Ile Gly Trp Phe Arg Gln Ala Pro Gly Lys Glu Arg

35 40 45

Glu Gly Val Ser Cys Ile Ser Gly Thr Gly Gly Ile Thr His Tyr Ala

50 55 60

Asp Ser Val Lys Gly Arg Phe Thr Ile Ser Arg Asp Ile Ala Lys Thr

65 70 75 80

Thr Val Tyr Leu Gln Met Asn Ser Leu Asn Ser Glu Asp Thr Ala Val

85 90 95

Tyr Tyr Cys Ala Ala Asp Glu Arg Cys Thr Asp Arg Leu Ile Arg Pro

100 105 110

Pro Thr Tyr Trp Gly Gln Gly Thr Gln Val Thr Val Ser Ser

115 120 125

<210> 13

<211> 126

<212> PRT

<213> Artificial Sequence

<400> 13

Gln Leu Gln Leu Val Ala Ser Gly Gly Gly Leu Val Gln Pro Gly Gly

1 5 10 15

Ser Leu Arg Leu Ser Cys Ala Leu Ser Gly Phe Thr Leu Arg Glu Leu

20 25 30

Asp Glu Phe Ala Ile Gly Trp Phe Arg Gln Ala Pro Gly Lys Glu Arg

35 40 45

Glu Gly Val Ser Cys Ile Ser Gly Thr Gly Gly Ile Thr His Tyr Ala

50 55 60

Asp Ser Val Lys Gly Arg Phe Thr Ile Ser Arg Asp Ile Ala Lys Thr

65 70 75 80

Thr Val Tyr Leu Gln Met Asn Ser Leu Asn Ser Glu Asp Thr Ala Val

85 90 95

Tyr Tyr Cys Ala Ala Asp Glu Arg Cys Thr Asp Arg Leu Ile Arg Pro

100 105 110

Pro Thr Tyr Trp Gly Gln Gly Thr Gln Val Thr Val Ser Ser

115 120 125

<210> 14

<211> 126

<212> PRT

<213> Artificial Sequence

<400> 14

Gln Leu Gln Leu Val Glu Ser Gly Gly Gly Leu Val Gln Pro Gly Gly

1 5 10 15

Ser Leu Arg Leu Ser Cys Ala Leu Ser Gly Phe Thr Leu Arg Glu Leu

20 25 30

Asp Glu Phe Ala Ile Gly Trp Phe Arg Gln Ala Pro Gly Lys Glu Arg

35 40 45

Glu Gly Val Ser Cys Ile Ser Gly Thr Gly Gly Ile Thr His Tyr Ala

50 55 60

Asp Ser Val Lys Gly Arg Phe Thr Ile Ser Arg Asp Ile Ala Lys Thr

65 70 75 80

Thr Val Tyr Leu Gln Met Asn Ser Leu Asn Ser Glu Asp Thr Ala Val

85 90 95

Tyr Tyr Cys Ala Ala Asp Glu Arg Cys Thr Asp Arg Leu Ile Arg Pro

100 105 110

Pro Thr Tyr Trp Gly Gln Gly Thr Gln Val Thr Val Ser Ser

115 120 125

<210> 15

<211> 126

<212> PRT

<213> Artificial Sequence

<400> 15

Gln Leu Gln Leu Gly Ala Ser Gly Gly Gly Leu Val Gln Pro Gly Gly

1 5 10 15

Ser Leu Arg Leu Ser Cys Ala Ala Ser Gly Phe Thr Leu Arg Glu Leu

20 25 30

Asp Glu Phe Ala Ile Gly Trp Phe Arg Gln Ala Pro Gly Lys Glu Arg

35 40 45

Glu Gly Val Ser Cys Ile Ser Gly Thr Gly Gly Ile Thr His Tyr Ala

50 55 60

Asp Ser Val Lys Gly Arg Phe Thr Ile Ser Arg Asp Ile Ala Lys Thr

65 70 75 80

Thr Val Tyr Leu Gln Met Asn Ser Leu Asn Ser Glu Asp Thr Ala Val

85 90 95

Tyr Tyr Cys Ala Ala Asp Glu Arg Cys Thr Asp Arg Leu Ile Arg Pro

100 105 110

Pro Thr Tyr Trp Gly Gln Gly Thr Gln Val Thr Val Ser Ser

115 120 125

<210> 16

<211> 126

<212> PRT

<213> Artificial Sequence

<400> 16

Glu Val Gln Leu Gly Ala Ser Gly Gly Gly Leu Val Gln Pro Gly Gly

1 5 10 15

Ser Leu Arg Leu Ser Cys Ala Leu Ser Gly Phe Thr Leu Arg Glu Leu

20 25 30

Asp Glu Phe Ala Ile Gly Trp Phe Arg Gln Ala Pro Gly Lys Glu Arg

35 40 45

Glu Gly Val Ser Cys Ile Ser Gly Thr Gly Gly Ile Thr His Tyr Ala

50 55 60

Asp Ser Val Lys Gly Arg Phe Thr Ile Ser Arg Asp Ile Ala Lys Thr

65 70 75 80

Thr Val Tyr Leu Gln Met Asn Ser Leu Asn Ser Glu Asp Thr Ala Val

85 90 95

Tyr Tyr Cys Ala Ala Asp Glu Arg Cys Thr Asp Arg Leu Ile Arg Pro

100 105 110

Pro Thr Tyr Trp Gly Gln Gly Thr Gln Val Thr Val Ser Ser

115 120 125

<210> 17

<211> 126

<212> PRT

<213> Artificial Sequence

<400> 17

Gln Leu Gln Leu Gly Ala Ser Gly Gly Gly Leu Val Gln Pro Gly Gly

1 5 10 15

Ser Leu Arg Leu Ser Cys Ala Leu Ser Gly Phe Thr Leu Arg Glu Leu

20 25 30

Asp Glu Phe Ala Ile Gly Trp Phe Arg Gln Ala Pro Gly Lys Glu Arg

35 40 45

Glu Gly Val Ser Cys Ile Ser Gly Thr Gly Gly Ile Thr His Tyr Ala

50 55 60

Asp Ser Val Lys Gly Arg Phe Thr Ile Ser Arg Asp Asn Ser Lys Thr

65 70 75 80

Thr Val Tyr Leu Gln Met Asn Ser Leu Asn Ser Glu Asp Thr Ala Val

85 90 95

Tyr Tyr Cys Ala Ala Asp Glu Arg Cys Thr Asp Arg Leu Ile Arg Pro

100 105 110

Pro Thr Tyr Trp Gly Gln Gly Thr Gln Val Thr Val Ser Ser

115 120 125

<210> 18

<211> 126

<212> PRT

<213> Artificial Sequence

<400> 18

Gln Leu Gln Leu Gly Ala Ser Gly Gly Gly Leu Val Gln Pro Gly Gly

1 5 10 15

Ser Leu Arg Leu Ser Cys Ala Leu Ser Gly Phe Thr Leu Arg Glu Leu

20 25 30

Asp Glu Phe Ala Ile Gly Trp Phe Arg Gln Ala Pro Gly Lys Glu Arg

35 40 45

Glu Gly Val Ser Cys Ile Ser Gly Thr Gly Gly Ile Thr His Tyr Ala

50 55 60

Asp Ser Val Lys Gly Arg Phe Thr Ile Ser Arg Asp Ile Ala Lys Asn

65 70 75 80

Thr Val Tyr Leu Gln Met Asn Ser Leu Asn Ser Glu Asp Thr Ala Val

85 90 95

Tyr Tyr Cys Ala Ala Asp Glu Arg Cys Thr Asp Arg Leu Ile Arg Pro

100 105 110

Pro Thr Tyr Trp Gly Gln Gly Thr Gln Val Thr Val Ser Ser

115 120 125

<210> 19

<211> 126

<212> PRT

<213> Artificial Sequence

<400> 19

Gln Leu Gln Leu Gly Ala Ser Gly Gly Gly Leu Val Gln Pro Gly Gly

1 5 10 15

Ser Leu Arg Leu Ser Cys Ala Leu Ser Gly Phe Thr Leu Arg Glu Leu

20 25 30

Asp Glu Phe Ala Ile Gly Trp Phe Arg Gln Ala Pro Gly Lys Glu Arg

35 40 45

Glu Gly Val Ser Cys Ile Ser Gly Thr Gly Gly Ile Thr His Tyr Ala

50 55 60

Asp Ser Val Lys Gly Arg Phe Thr Ile Ser Arg Asp Ile Ala Lys Thr

65 70 75 80

Thr Leu Tyr Leu Gln Met Asn Ser Leu Asn Ser Glu Asp Thr Ala Val

85 90 95

Tyr Tyr Cys Ala Ala Asp Glu Arg Cys Thr Asp Arg Leu Ile Arg Pro

100 105 110

Pro Thr Tyr Trp Gly Gln Gly Thr Gln Val Thr Val Ser Ser

115 120 125

<210> 20

<211> 126

<212> PRT

<213> Artificial Sequence

<400> 20

Gln Leu Gln Leu Gly Ala Ser Gly Gly Gly Leu Val Gln Pro Gly Gly

1 5 10 15

Ser Leu Arg Leu Ser Cys Ala Leu Ser Gly Phe Thr Leu Arg Glu Leu

20 25 30

Asp Glu Phe Ala Ile Gly Trp Phe Arg Gln Ala Pro Gly Lys Glu Arg

35 40 45

Glu Gly Val Ser Cys Ile Ser Gly Thr Gly Gly Ile Thr His Tyr Ala

50 55 60

Asp Ser Val Lys Gly Arg Phe Thr Ile Ser Arg Asp Ile Ala Lys Thr

65 70 75 80

Thr Val Tyr Leu Gln Met Asn Ser Leu Arg Ala Glu Asp Thr Ala Val

85 90 95

Tyr Tyr Cys Ala Ala Asp Glu Arg Cys Thr Asp Arg Leu Ile Arg Pro

100 105 110

Pro Thr Tyr Trp Gly Gln Gly Thr Gln Val Thr Val Ser Ser

115 120 125

<210> 21

<211> 126

<212> PRT

<213> Artificial Sequence

<400> 21

Glu Leu Gln Leu Gly Ala Ser Gly Gly Gly Leu Val Gln Pro Gly Gly

1 5 10 15

Ser Leu Arg Leu Ser Cys Ala Leu Ser Gly Phe Thr Leu Arg Glu Leu

20 25 30

Asp Glu Phe Ala Ile Gly Trp Phe Arg Gln Ala Pro Gly Lys Glu Arg

35 40 45

Glu Gly Val Ser Cys Ile Ser Gly Thr Gly Gly Ile Thr His Tyr Ala

50 55 60

Asp Ser Val Lys Gly Arg Phe Thr Ile Ser Arg Asp Asn Ser Lys Asn

65 70 75 80

Thr Leu Tyr Leu Gln Met Asn Ser Leu Arg Ala Glu Asp Thr Ala Val

85 90 95

Tyr Tyr Cys Ala Ala Asp Glu Arg Cys Thr Asp Arg Leu Ile Arg Pro

100 105 110

Pro Thr Tyr Trp Gly Gln Gly Thr Gln Val Thr Val Ser Ser

115 120 125

<210> 22

<211> 126

<212> PRT

<213> Artificial Sequence

<400> 22

Gln Leu Gln Leu Gly Ala Ser Gly Gly Gly Leu Val Gln Pro Gly Gly

1 5 10 15

Ser Leu Arg Leu Ser Cys Ala Leu Ser Gly Phe Thr Leu Arg Glu Leu

20 25 30

Asp Glu Phe Ala Ile Gly Trp Phe Arg Gln Ala Pro Gly Lys Glu Arg

35 40 45

Glu Gly Val Ser Cys Ile Ser Gly Thr Gly Gly Ile Thr His Tyr Ala

50 55 60

Asp Ser Val Lys Gly Arg Phe Thr Ile Ser Arg Asp Ile Ala Lys Asn

65 70 75 80

Thr Val Tyr Leu Gln Met Asn Ser Leu Asn Ser Glu Asp Thr Ala Val

85 90 95

Tyr Tyr Cys Ala Ala Asp Glu Arg Cys Thr Asp Arg Leu Ile Arg Pro

100 105 110

Pro Thr Tyr Trp Gly Gln Gly Thr Gln Val Thr Val Ser Ser

115 120 125

<210> 23

<211> 126

<212> PRT

<213> Artificial Sequence

<400> 23

Gln Leu Gln Leu Gly Ala Ser Gly Gly Gly Leu Val Gln Pro Gly Gly

1 5 10 15

Ser Leu Arg Leu Ser Cys Ala Leu Ser Gly Phe Thr Leu Arg Glu Leu

20 25 30

Asp Glu Phe Ala Ile Gly Trp Phe Arg Gln Ala Pro Gly Lys Glu Arg

35 40 45

Glu Gly Val Ser Cys Ile Ser Gly Thr Gly Gly Ile Thr His Tyr Ala

50 55 60

Asp Ser Val Lys Gly Arg Phe Thr Ile Ser Arg Asp Ile Ala Lys Thr

65 70 75 80

Thr Leu Tyr Leu Gln Met Asn Ser Leu Asn Ser Glu Asp Thr Ala Val

85 90 95

Tyr Tyr Cys Ala Ala Asp Glu Arg Cys Thr Asp Arg Leu Ile Arg Pro

100 105 110

Pro Thr Tyr Trp Gly Gln Gly Thr Gln Val Thr Val Ser Ser

115 120 125

<210> 24

<211> 229

<212> PRT

<213> Artificial Sequence

<400> 24

Glu Ser Lys Tyr Gly Pro Pro Cys Pro Pro Cys Pro Ala Pro Glu Phe

1 5 10 15

Leu Gly Gly Pro Ser Val Phe Leu Phe Pro Pro Lys Pro Lys Asp Thr

20 25 30

Leu Met Ile Ser Arg Thr Pro Glu Val Thr Cys Val Val Val Asp Val

35 40 45

Ser Gln Glu Asp Pro Glu Val Gln Phe Asn Trp Tyr Val Asp Gly Val

50 55 60

Glu Val His Asn Ala Lys Thr Lys Pro Arg Glu Glu Gln Phe Asn Ser

65 70 75 80

Thr Tyr Arg Val Val Ser Val Leu Thr Val Leu His Gln Asp Trp Leu

85 90 95

Asn Gly Lys Glu Tyr Lys Cys Lys Val Ser Asn Lys Gly Leu Pro Ser

100 105 110

Ser Ile Glu Lys Thr Ile Ser Lys Ala Lys Gly Gln Pro Arg Glu Pro

115 120 125

Gln Val Tyr Thr Leu Pro Pro Ser Gln Glu Glu Met Thr Lys Asn Gln

130 135 140

Val Ser Leu Thr Cys Leu Val Lys Gly Phe Tyr Pro Ser Asp Ile Ala

145 150 155 160

Val Glu Trp Glu Ser Asn Gly Gln Pro Glu Asn Asn Tyr Lys Thr Thr

165 170 175

Pro Pro Val Leu Asp Ser Asp Gly Ser Phe Phe Leu Tyr Ser Arg Leu

180 185 190

Thr Val Asp Lys Ser Arg Trp Gln Glu Gly Asn Val Phe Ser Cys Ser

195 200 205

Val Met His Glu Ala Leu His Asn His Tyr Thr Gln Lys Ser Leu Ser

210 215 220

Leu Ser Leu Gly Lys

225

<210> 25

<211> 24

<212> DNA

<213> Artificial Sequence

<400> 25

gtcctggctg ctcttctaca aggc 24

<210> 26

<211> 23

<212> DNA

<213> Artificial Sequence

<400> 26

ggtacgtgct gttgaactgt tcc 23

<210> 27

<211> 29

<212> DNA

<213> Artificial Sequence

<400> 27

gatgtgcagc tgcaggagtc tggrggagg 29

<210> 28

<211> 35

<212> DNA

<213> Artificial Sequence

<400> 28

ggactagtgc ggccgctgga gacggtgacc tgggt 35

Claims (13)

1. A mesothelin binding molecule comprising an anti-mesothelin single domain antibody having complementarity determining region CDRs comprising CDR1, CDR2 and CDR3, wherein CDR1 comprises the sequence set forth in SEQ ID No. 1, and/or CDR2 comprises the sequence set forth in SEQ ID No. 2, and/or CDR3 comprises the sequence set forth in SEQ ID No. 3.

2. The mesothelin binding molecule of claim 1, wherein,

the FR region of the single domain antibody comprises the FR region of any one of the VHHs selected from SEQ ID NOS 4-23, and/or

The single domain antibody VHH is shown as any one of SEQ ID NO. 4-23, and/or

The mesothelin-binding molecule is a monovalent or multivalent single domain antibody, multispecific single domain antibody, heavy chain antibody or antigen-binding fragment thereof, antibody or antigen-binding fragment thereof comprising one, two or more of said single domain antibodies.

3. The mesothelin binding molecule of claim 2, wherein the mesothelin binding molecule is a heavy chain antibody further comprising heavy chain constant regions CH2 and CH3,

preferably, the heavy chain constant region comprises the sequence shown in SEQ ID NO. 24.

4. A polynucleotide selected from the group consisting of:

(1) a coding sequence for the mesothelin binding molecule of any one of claims 1-3;

(2) the complement of (1);

(3) a fragment of 5 to 50bp of any one of (1) or (2).

5. A nucleic acid construct comprising the polynucleotide of claim 4,

preferably, the nucleic acid construct is a recombinant vector or an expression vector.

6. A bacteriophage comprising the mesothelin binding molecule of any one of claims 1-5,

preferably, the mesothelin-binding molecule is displayed on the phage surface.

7. A host cell, wherein the host cell:

(1) expressing the mesothelin binding molecule of any one of claims 1-3; and/or

(2) Comprising the polynucleotide of claim 4; and/or

(3) Comprising the nucleic acid construct of claim 5.

8. A method of producing a mesothelin-binding molecule comprising: culturing the host cell of claim 7 under conditions suitable for the production of a mesothelin-binding molecule, and optionally purifying the mesothelin-binding molecule from the culture.

9. A pharmaceutical composition comprising the mesothelin binding molecule of any one of claims 1-3, the polynucleotide of claim 4, the nucleic acid construct of claim 5, the bacteriophage of claim 6 or the host cell of claim 7, and a pharmaceutically acceptable excipient,

preferably, the pharmaceutical composition is for use in the treatment of cancer.

10. Use of the mesothelin binding molecule of any one of claims 1-3 in the manufacture of a medicament for the prevention or treatment of cancer.

11. A kit for detecting mesothelin for use in assessing the efficacy of a drug treatment or diagnosing cancer, said kit comprising the mesothelin binding molecule of any one of claims 1-3, the polynucleotide of claim 4, the nucleic acid construct of claim 5, the bacteriophage of claim 6 or the host cell of claim 7,

preferably, the kit further comprises reagents for detecting the binding of mesothelin to the single domain antibody, antibody or antigen-binding fragment thereof,

more preferably, the reagent is a reagent for detecting the binding by enzyme-linked immunosorbent assay.

12. A non-diagnostic method for detecting the presence of mesothelin in a sample, said method comprising: incubating a sample with a mesothelin binding molecule as defined in any one of claims 1 to 3, and detecting binding of mesothelin to the single domain antibody, antibody or antigen binding fragment thereof, thereby determining the presence of mesothelin in the sample.

13. Use of the mesothelin binding molecule of any one of claims 1-3 in the manufacture of a kit for detecting mesothelin, assessing the efficacy of a drug treatment or diagnosing cancer in a sample.

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