Humanized antibody capable of binding to HEG1 protein

Abstract

The present invention provides a humanized antibody capable of binding to HEG1 protein or an antigen-binding fragment thereof, the antibody being a humanized antibody capable of binding to human HEG1 protein expressed in a mesothelioma cell.

Description

Humanized antibody that binds to HEG1 protein

[0001] The present disclosure relates to humanized antibodies that bind to the HEG1 protein.

[0002] Malignant mesothelioma, a malignant tumor primarily caused by asbestos exposure, is a disease that has become a major social problem. Early detection is difficult, and it is considered one of the malignant tumors with a poor prognosis. Malignant mesothelioma can sometimes pathologically resemble metastatic adenocarcinoma, sarcoma, or reactive mesothelial cell proliferation, which is benign, and pathological differentiation is often difficult. In addition, it can take on a variety of histological types, including epithelial and sarcomatous types, making diagnosis difficult.

[0003] It has been shown that the HEG1 protein is effective as a marker for diagnosing malignant mesothelioma (Patent Document 1). Patent Document 1 reveals that mesothelioma can be detected with high sensitivity and specificity by reacting a mouse antibody that binds to the HEG1 protein with mesothelioma tissue.

[0004] WO2017 / 141604

[0005] The present disclosure provides humanized antibodies that bind to the HEG1 protein.

[0006] The present inventors have developed a humanized antibody that binds to the HEG1 protein, which is suitable for pharmaceutical use.

[0007] The present invention provides the following: [1] An antibody or an antigen-binding fragment thereof, which is a humanized antibody capable of binding to human HEG1 protein expressed in mesothelioma cells, and which comprises a heavy chain variable region including a heavy chain CDR1 having the amino acid sequence set forth in SEQ ID NO: 37, a heavy chain CDR2 having the amino acid sequence set forth in SEQ ID NO: 43, and a heavy chain CDR3 having the amino acid sequence set forth in SEQ ID NO: 51, and a light chain variable region including a light chain CDR1 having the amino acid sequence set forth in SEQ ID NO: 62, a light chain CDR2 having the amino acid sequence set forth in SEQ ID NO: 75, and a light chain CDR3 having the amino acid sequence set forth in SEQ ID NO: 82. [2] The antibody or antigen-binding fragment thereof according to [1] above, comprising a heavy chain variable region including a heavy chain CDR1 having the amino acid sequence set forth in SEQ ID NO: 37, a heavy chain CDR2 having the amino acid sequence set forth in SEQ ID NO: 43, and a heavy chain CDR3 having the amino acid sequence set forth in SEQ ID NO: 51, and a light chain variable region including a light chain CDR1 having the amino acid sequence set forth in SEQ ID NO: 63, a light chain CDR2 having the amino acid sequence set forth in SEQ ID NO: 75, and a light chain CDR3 having the amino acid sequence set forth in SEQ ID NO: 82, or an antigen-binding fragment thereof. [3] The antibody or antigen-binding fragment thereof according to [1] or [2] above, wherein the heavy chain variable region comprises: (1) a heavy chain CDR1 having the amino acid sequence set forth in SEQ ID NO:89, a heavy chain CDR2 having the amino acid sequence set forth in SEQ ID NO:90, and a heavy chain CDR3 having the amino acid sequence set forth in SEQ ID NO:91; (2) a heavy chain CDR1 having the amino acid sequence set forth in SEQ ID NO:92, a heavy chain CDR2 having the amino acid sequence set forth in SEQ ID NO:93, and a heavy chain CDR3 having the amino acid sequence set forth in SEQ ID NO:94; (3) a heavy chain CDR1 having the amino acid sequence set forth in SEQ ID NO:95, a heavy chain CDR2 having the amino acid sequence set forth in SEQ ID NO:96, and a heavy chain CDR3 having the amino acid sequence set forth in SEQ ID NO:97; (4) a heavy chain CDR1 having the amino acid sequence set forth in SEQ ID NO:98, a heavy chain CDR2 having the amino acid sequence set forth in SEQ ID NO:99, and a heavy chain CDR3 having the amino acid sequence set forth in SEQ ID NO:100;(5) a heavy chain CDR1 having the amino acid sequence set forth in SEQ ID NO: 101, a heavy chain CDR2 having the amino acid sequence set forth in SEQ ID NO: 102, and a heavy chain CDR3 having the amino acid sequence set forth in SEQ ID NO: 103; (6) a heavy chain CDR1 having the amino acid sequence set forth in SEQ ID NO: 104, a heavy chain CDR2 having the amino acid sequence set forth in SEQ ID NO: 105, and a heavy chain CDR3 having the amino acid sequence set forth in SEQ ID NO: 106; (7) a heavy chain CDR1 having the amino acid sequence set forth in SEQ ID NO: 110, a heavy chain CDR2 having the amino acid sequence set forth in SEQ ID NO: 111, and a heavy chain CDR3 having the amino acid sequence set forth in SEQ ID NO: 112; or (8) a heavy chain CDR1 having the amino acid sequence set forth in SEQ ID NO: 113, a heavy chain CDR2 having the amino acid sequence set forth in SEQ ID NO: 114, and a heavy chain CDR3 having the amino acid sequence set forth in SEQ ID NO: 115. An antibody or antigen-binding fragment thereof. [4] The antibody or antigen-binding fragment thereof according to any one of [1] to [3] above, wherein the light chain variable region comprises: (1) a light chain CDR1 having the amino acid sequence set forth in SEQ ID NO: 116, a light chain CDR2 having the amino acid sequence set forth in SEQ ID NO: 117, and a light chain CDR3 having the amino acid sequence set forth in SEQ ID NO: 118; (2) a light chain CDR1 having the amino acid sequence set forth in SEQ ID NO: 119, a light chain CDR2 having the amino acid sequence set forth in SEQ ID NO: 120, and a light chain CDR3 having the amino acid sequence set forth in SEQ ID NO: 121; (3) a light chain CDR1 having the amino acid sequence set forth in SEQ ID NO: 122, a light chain CDR2 having the amino acid sequence set forth in SEQ ID NO: 123, and a light chain CDR3 having the amino acid sequence set forth in SEQ ID NO: 124; (4) a light chain CDR1 having the amino acid sequence set forth in SEQ ID NO: 128, a light chain CDR2 having the amino acid sequence set forth in SEQ ID NO: 129, and a light chain CDR3 having the amino acid sequence set forth in SEQ ID NO: 130; (5) A light chain CDR1 having the amino acid sequence set forth in SEQ ID NO: 131, a light chain CDR2 having the amino acid sequence set forth in SEQ ID NO: 132, and a light chain CDR3 having the amino acid sequence set forth in SEQ ID NO: 133; (6) A light chain CDR1 having the amino acid sequence set forth in SEQ ID NO: 134, a light chain CDR2 having the amino acid sequence set forth in SEQ ID NO: 135, and a light chain CDR3 having the amino acid sequence set forth in SEQ ID NO: 136;(7) a light chain CDR1 having the amino acid sequence set forth in SEQ ID NO: 137, a light chain CDR2 having the amino acid sequence set forth in SEQ ID NO: 138, and a light chain CDR3 having the amino acid sequence set forth in SEQ ID NO: 139; (8) a light chain CDR1 having the amino acid sequence set forth in SEQ ID NO: 140, a light chain CDR2 having the amino acid sequence set forth in SEQ ID NO: 141, and a light chain CDR3 having the amino acid sequence set forth in SEQ ID NO: 142; (9) a light chain CDR1 having the amino acid sequence set forth in SEQ ID NO: 143, a light chain CDR2 having the amino acid sequence set forth in SEQ ID NO: 144, and a light chain CDR3 having the amino acid sequence set forth in SEQ ID NO: 145; (10) a light chain CDR1 having the amino acid sequence set forth in SEQ ID NO: 146, a light chain CDR2 having the amino acid sequence set forth in SEQ ID NO: 147, and a light chain CDR3 having the amino acid sequence set forth in SEQ ID NO: 148; (11) a light chain CDR1 having the amino acid sequence set forth in SEQ ID NO: 149, a light chain CDR2 having the amino acid sequence set forth in SEQ ID NO: 150, and a light chain CDR3 having the amino acid sequence set forth in SEQ ID NO: 151; (12) light chain CDR1 having the amino acid sequence set forth in SEQ ID NO: 152, light chain CDR2 having the amino acid sequence set forth in SEQ ID NO: 153, and light chain CDR3 having the amino acid sequence set forth in SEQ ID NO: 154; (13) light chain CDR1 having the amino acid sequence set forth in SEQ ID NO: 155, light chain CDR2 having the amino acid sequence set forth in SEQ ID NO: 156, and light chain CDR3 having the amino acid sequence set forth in SEQ ID NO: 157; (14) light chain CDR1 having the amino acid sequence set forth in SEQ ID NO: 158, light chain CDR2 having the amino acid sequence set forth in SEQ ID NO: 159, and light chain CDR3 having the amino acid sequence set forth in SEQ ID NO: 160; (15) light chain CDR1 having the amino acid sequence set forth in SEQ ID NO: 161, light chain CDR2 having the amino acid sequence set forth in SEQ ID NO: 162, and light chain CDR3 having the amino acid sequence set forth in SEQ ID NO: 163; (16) light chain CDR1 having the amino acid sequence set forth in SEQ ID NO: 173, light chain CDR2 having the amino acid sequence set forth in SEQ ID NO: 174, and light chain CDR3 having the amino acid sequence set forth in SEQ ID NO: 175;(17) An antibody or antigen-binding fragment thereof comprising a light chain CDR1 having the amino acid sequence set forth in SEQ ID NO: 176, a light chain CDR2 having the amino acid sequence set forth in SEQ ID NO: 177, and a light chain CDR3 having the amino acid sequence set forth in SEQ ID NO: 178; or (18) a light chain CDR1 having the amino acid sequence set forth in SEQ ID NO: 179, a light chain CDR2 having the amino acid sequence set forth in SEQ ID NO: 180, and a light chain CDR3 having the amino acid sequence set forth in SEQ ID NO: 181. [5] The antibody or antigen-binding fragment thereof according to any of [1] to [4] above, comprising any of the heavy chain variable regions set forth in [3] above and any of the light chain variable regions set forth in [4] above. [6] The antibody or antigen-binding fragment thereof according to any of [1] to [5] above, wherein the heavy chain variable region comprises a heavy chain CDR1 having the amino acid sequence set forth in SEQ ID NO: 104, a heavy chain CDR2 having the amino acid sequence set forth in SEQ ID NO: 105, and a heavy chain CDR3 having the amino acid sequence set forth in SEQ ID NO: 106, and the light chain variable region comprises a light chain CDR1 having the amino acid sequence set forth in SEQ ID NO: 149, a light chain CDR2 having the amino acid sequence set forth in SEQ ID NO: 150, and a light chain CDR3 having the amino acid sequence set forth in SEQ ID NO: 151. [7] The antibody or antigen-binding fragment thereof according to any of [1] to [6] above, wherein the heavy chain variable region comprises a framework region 1 having the amino acid sequence set forth in SEQ ID NO: 32, a framework region 2 having the amino acid sequence set forth in SEQ ID NO: 40, a framework region 3 having the amino acid sequence set forth in SEQ ID NO: 46, and a framework region 4 having the amino acid sequence set forth in SEQ ID NO: 54. [8] The antibody or antigen-binding fragment thereof according to any of [1] to [7] above, wherein the light chain variable region has a framework region 1 having the amino acid sequence set forth in SEQ ID NO: 57, a framework region 2 having the amino acid sequence set forth in SEQ ID NO: 72, a framework region 3 having the amino acid sequence set forth in SEQ ID NO: 79, and a framework region 4 having the amino acid sequence set forth in SEQ ID NO: 86. [9] The heavy chain variable region has an amino acid sequence selected from the group consisting of SEQ ID NOs: 1 to 6, 8, and 9, and the light chain variable region has an amino acid sequence selected from the group consisting of SEQ ID NOs: 10, 12 to 15, 17 to 21, and 29 to 31.The antibody or antigen-binding fragment thereof according to any one of [1] to [8] above.

[10] The antibody or antigen-binding fragment thereof according to any one of [1] to [9] above, wherein the heavy chain variable region has the amino acid sequence set forth in SEQ ID NO: 6 and the light chain variable region has the amino acid sequence set forth in SEQ ID NO: 21.

[0008]

[11] A composition for use in targeting the HEG1 protein expressed in mesothelioma, comprising the antibody or its antigen-binding fragment.

[12] Use of the antibody or its antigen-binding fragment in the manufacture of a composition for use in targeting the HEG1 protein expressed in mesothelioma.

[13] A method for targeting the HEG1 protein expressed in mesothelioma in a subject, comprising administering to the subject an effective amount of a composition comprising the antibody or its antigen-binding fragment.

[0009] Figure 1 shows the binding activity of humanized antibodies comprising a combination of a humanized heavy chain variable region and a humanized light chain variable region to HEG1. Information about the heavy and light chains of the antibodies used is attached to each bar. The activity is compared to that of a mouse antibody (parent antibody) having a mouse heavy chain variable region (xiH) and a mouse light chain variable region (xiL). Figure 2 shows the binding activity of humanized antibodies comprising a combination of a humanized heavy chain variable region and a humanized light chain variable region to HEG1. Information about the heavy and light chains of the antibodies used is attached to each bar. (-) indicates the background in the absence of antibody. Figure 3 shows the binding activity of humanized antibodies comprising a combination of a humanized heavy chain variable region and a humanized light chain variable region to HEG1. Information about the heavy and light chains of the antibodies used is attached to each bar. Figure 4 shows the binding activity of humanized antibodies comprising a combination of a humanized heavy chain variable region and a humanized light chain variable region to HEG1. Each bar contains information about the heavy and light chains of the antibody used. Figure 5 shows the binding activity to HEG1 of humanized antibodies comprising a combination of a humanized heavy chain variable region and a humanized light chain variable region. Each bar contains information about the heavy and light chains of the antibody used. Figure 6 shows the binding activity to HEG1 of humanized antibodies comprising a combination of a humanized heavy chain variable region and a humanized light chain variable region. Each bar contains information about the heavy and light chains of the antibody used. Figure 7 shows the effect of signal peptides on the production yield of each humanized antibody. Figure 8 shows the results of SDS-PAGE of each antibody purified from the culture supernatant after expressing each heavy and light chain in a CHO cell line. In Figure 9, the left column shows the results of measuring the affinity of each purified humanized SKM9-2 antibody to a synthetic carbohydrate epitope using Biacore, and the right column shows the results of measuring the binding of each purified humanized SKM9-2 antibody to the mesothelioma cell line NCI-H226 using flow cytometry. Specific Description of the Invention

[0010] <Definitions> As used herein, the term "subject" may be a mammal, including, for example, primates such as humans, marmosets, and chimpanzees; laboratory animals such as rats, mice, and rabbits; livestock animals such as pigs, cows, horses, sheep, and goats; and pets such as dogs and cats, and is preferably a human. More preferably, the subject may be a "cancer patient" suffering from or at risk of having a tumor or cancer. Even more preferably, the subject may be suffering from or at risk of having mesothelioma. The term "patient" refers to a subject suffering from cancer, and is not limited to humans, but is preferably a human.

[0011] As used herein, "antibody" refers to an immunoglobulin, a protein having a structure in which two heavy chains (H chains) and two light chains (L chains) stabilized by disulfide bonds are associated. The heavy chain consists of a heavy chain variable region VH, heavy chain constant regions CH1, CH2, and CH3, and a hinge region located between CH1 and CH2. The light chain consists of a light chain variable region VL and a light chain constant region CL. Of these, the variable region fragment (Fv) consisting of VH and VL is directly involved in antigen binding and provides antibody diversity. The antigen-binding region consisting of VL, CL, VH, and CH1 is called the Fab region, and the region consisting of the hinge region, CH2, and CH3 is called the Fc region. Within the variable regions, the regions that directly contact the antigen are particularly variable and are called complementarity-determining regions (CDRs). Portions other than the CDRs that show relatively little variation are called framework regions (FRs). The light chain and heavy chain variable regions each have three CDRs, which are called heavy chain CDR1-3 and light chain CDR1-3, respectively, from the N-terminus. Each CDR is incorporated into a framework region. The heavy chain variable region of an antibody has, in this order from the N-terminus to the C-terminus, heavy chain framework region 1, heavy chain CDR1, heavy chain framework region 2, heavy chain CDR2, heavy chain framework region 3, heavy chain CDR3, and heavy chain framework region 4. The light chain variable region of an antibody has, in this order from the N-terminus to the C-terminus, light chain framework region 1, light chain CDR1, light chain framework region 2, light chain CDR2, light chain framework region 3, light chain CDR3, and light chain framework region 4. The antibody may be a recombinant protein (recombinant antibody) and may be produced in animal cells such as Chinese hamster ovary cells (CHO cells). The origin of the antibody is not particularly limited, but examples include antibodies from non-human animals, non-human mammals (e.g., mouse antibodies, rat antibodies, camel antibodies), and human antibodies. The antibody may also be a chimeric antibody, a humanized antibody, or a fully humanized antibody. The antibody may be a polyclonal antibody or a monoclonal antibody, preferably a monoclonal antibody.A "chimeric antibody" is an antibody in which the heavy chain variable region and light chain constant region of different species are linked to the heavy chain variable region and light chain constant region, respectively. A humanized antibody refers to an antibody in which the corresponding positions in a human antibody are replaced with amino acid sequences characteristic of antibodies of non-human origin. For example, an antibody has heavy chain CDRs 1-3 and light chain CDRs 1-3 of an antibody produced by immunizing a mouse or rat, with all other regions, including the four framework regions (FRs) of the heavy and light chains, derived from a human antibody. Such antibodies are sometimes called CDR-grafted antibodies. A "humanized antibody" may also include human chimeric antibodies. A "human chimeric antibody" is an antibody of non-human origin in which the constant regions of the non-human antibody are replaced with human antibody constant regions. The antibody may also be a bispecific antibody. The antibody may be an isolated antibody or a purified antibody. The antibody may be, for example, an IgG. The antibody can be, for example, an IgG1, IgG2 (eg, IgG2a and IgG2b), IgG3, or IgG4.

[0012] The variable regions of immunoglobulin chains generally share the same overall structure, including relatively conserved framework regions (FRs) linked by three hypervariable regions (more often referred to as "complementarity-determining regions" or CDRs). The CDRs from the two chains of each heavy / light chain pair are typically juxtaposed by the framework regions to form a structure that specifically binds to a specific epitope on a target protein (e.g., PCSK9). From the N-terminus to the C-terminus, naturally occurring light and heavy chain variable regions typically follow the following order of these elements: FR1, CDR1, FR2, CDR2, FR3, CDR3, and FR4. A numbering system has been devised to assign numbers to the amino acids that occupy positions in each of these domains. This numbering system is defined in Kabat Sequences of Proteins of Immunological Interest (1987 and 1991, NIH, Bethesda, MD) or Chothia & Lesk, 1987, J. Mol. Biol. 196:901-917; Chothia et al., 1989, Nature 342:878-883.

[0013] As used herein, the term "antigen-binding fragment" refers to a portion of an antibody that retains its ability to bind to an antigen. The antigen-binding fragment may include the heavy chain variable region, the light chain variable region, or both of an antibody of the present disclosure. The antigen-binding fragment may be chimerized or humanized. Examples of antigen-binding fragments include Fab, Fab', F(ab')2, and Fv. Antibody-binding fragments may also include recombinantly produced conjugates or functional equivalents (e.g., other antibody portions having the form of scFv (single-chain Fv), diabody, scDb, tandem scFv, leucine zipper, sc(Fv)2 (single-chain Fv)2, etc.). Such antibody antigen-binding fragments can be obtained, for example, by treating the antibody with an enzyme. For example, Fab can be obtained by digesting the antibody with papain. Alternatively, F(ab')2 can be obtained by digesting the antibody with pepsin, and Fab' can be obtained by further reducing this. Antigen-binding fragments of such antibodies can be used herein. In scFv, VL and VH are linked by an artificial polypeptide linker, allowing the same antigen specificity as the original antibody to be maintained. VL and VH can be linked in the order of VH and VL or VL and VH from the N-terminus. The linker can have a length of approximately 10 to 25 amino acids. The linker may be rich in glycine, or may contain amino acids such as serine and threonine to increase water solubility.

[0014] As used herein, "HEG1 protein" refers to a protein expressed on the membrane of mesothelioma cells (WO 2017 / 141604). According to WO 2017 / 141604, HEG1 protein is thought to be glycosylated on the membrane of mesothelioma cells. The glycosylation includes O-glycosylation. The glycosylation may include α2,3 sialylation. The glycosylation is thought to be specific to mesothelioma. Therefore, according to WO 2017 / 141604, mesothelioma cells can be detected using an antibody that binds to HEG1 protein having this glycosylation. Examples of human HEG1 protein include the nucleic acid sequence registered with the National Center for Biotechnology Information (NCBI) as NM_020733.1 and the protein having the amino acid sequence encoded thereby. Based on the results of gene ontology analysis, it is predicted that in the HEG1 protein, the signal peptide portion is the domain corresponding to positions 1 to 29 of the amino acid sequence, the extracellular domain is the domain corresponding to positions 30 to 1248 of the amino acid sequence, the transmembrane domain is the domain corresponding to positions 1249 to 1269 of the amino acid sequence, and the intracellular domain is the domain corresponding to positions 1270 to 1381 of the amino acid sequence. For example, the HEG1 protein may also include proteins having an amino acid sequence that is 90% or more, 95% or more, 98% or more, or 99% or more homologous to the amino acid sequence described above. For example, the HEG1 protein may contain one or more amino acid substitutions, insertions, additions, and / or deletions in the amino acid sequence represented by the amino acid sequence described above.

[0015] As used herein, amino acid sequences are represented by single letter codes: A represents alanine, R represents arginine, N represents asparagine, D represents aspartic acid, C represents cysteine, Q represents glutamine, E represents glutamic acid, G represents glycine, H represents histidine, I represents isoleucine, L represents leucine, K represents lysine, M represents methionine, F represents phenylalanine, P represents proline, S represents serine, T represents threonine, W represents tryptophan, Y represents tyrosine, and V represents valine.

[0016] As used herein, "mesothelioma" refers to a tumor derived from mesothelial cells. Known types of mesothelioma, depending on their site of origin, include pleural mesothelioma, peritoneal mesothelioma, pericardial mesothelioma, and tunica vaginalis mesothelioma. As used herein, mesothelioma refers to benign mesothelioma and / or malignant mesothelioma. Based on histological type, mesothelioma is broadly classified into epithelial mesothelioma, sarcomatoid mesothelioma, biphasic mesothelioma, and other mesotheliomas (such as desmoplastic mesothelioma). In some embodiments, mesothelioma may be malignant mesothelioma.

[0017] <Humanized Antibodies of the Present Disclosure> In the present disclosure, the antibody is an antibody that binds to HEG1 protein. The HEG1 protein may be a HEG1 protein expressed in mesothelioma cells (e.g., ACC-MESO4 cell line) (WO 2017 / 141604). The HEG1 protein expressed in mesothelioma cells may have mesothelioma-specific glycosylation. The glycosylation includes α2,3-sialylation because it is degraded by α2,3-neuraminidase treatment (WO 2017 / 141604). Furthermore, the glycosylation may be O-glycosylation because it is not degraded by N-glycanase (PNGase F) (WO 2017 / 141604).

[0018] In a preferred embodiment, the antibody of the present disclosure binds to the HEG1 protein expressed in mesothelioma cells. In a preferred embodiment, the antibody binds to the HEG1 protein in a manner dependent on O-glycosylation containing α2,3 sialic acid. That is, the antibody's binding ability to the HEG1 protein can be reduced or eliminated by treatment with α2,3 neuraminidase. The antibody's binding ability to the HEG1 protein can also be reduced or eliminated by treatment with proteinase K.

[0019] According to the present disclosure, there is provided a humanized antibody that binds to HEG1 protein (particularly human HEG1). In a preferred embodiment, the antibody of the present disclosure binds to HEG1 protein expressed in mesothelioma cells. In a preferred embodiment, the antibody binds to HEG1 protein in a manner dependent on O-glycosylation containing α2,3 sialic acid. That is, the antibody's binding ability to HEG1 protein can be reduced or eliminated by treatment with α2,3 neuraminidase. The antibody's binding ability to HEG1 protein can also be reduced or eliminated by treatment with proteinase K.

[0020] In certain aspects, the antibody of the present disclosure binds to the HEG1 protein expressed in mesothelioma cells (e.g., the ACC-MESO4 cell line). Such antibodies can be obtained by standard methods, for example, as described in WO 2017 / 141604. Specifically, for example, the antibody binds to the HEG1 protein expressed in mesothelioma cells (e.g., the ACC-MESO4 cell line), and in certain aspects, the binding can be eliminated or reduced by treating the HEG1 protein with proteinase K. For example, the antibody binds to the HEG1 protein expressed in mesothelioma cells (e.g., the ACC-MESO4 cell line), and in certain aspects, the binding can be eliminated or reduced by treating the HEG1 protein with α2,3 neuraminidase. In one aspect, the bond is not eliminated by treatment with one or more enzymes selected from the group consisting of β-N-acetylglucosaminidase, N-glycanase (PNGase F), lysozyme, and hyaluronidase. The treatment is carried out under conditions appropriate for the individual treatment. In one aspect, the antibody can be a human antibody. A human antibody can be produced by immunizing a non-human mammal (e.g., a mouse) incorporating a human IgG locus with an immunogen. In one aspect, a mouse incorporating a human heavy chain variable region inserted upstream of the mouse IgG heavy chain constant region and a human light chain variable region inserted upstream of the mouse IgG light chain constant region is immunized with an immunogen to obtain a human chimeric antibody, and the constant regions can then be replaced with corresponding human constant regions (see, e.g., WO 2002 / 066630A and WO 2011 / 004192A). A humanized antibody can be produced by removing the six CDRs of a human antibody and replacing them with the corresponding CDRs (six CDRs) of a resulting antibody.

[0021] In one aspect, the antibody or antigen-binding fragment thereof of the present disclosure is a humanized antibody that binds to a partial peptide of the HEG1 protein (particularly human HEG1). The partial peptide may be, for example, an antibody that binds to a peptide having the amino acid sequence set forth in SEQ ID NO: 182 (SKSPSLVSLPT). The partial peptide may be, for example, a peptide produced by mesothelioma cells (e.g., ACC-MESO4 cell line). The peptide may be obtained as a fusion protein by linking it to the N-terminus of a protein in which a GPI anchor signal is attached to the N-terminus of human SLURP1 (SEQ ID NO: 183; hereinafter referred to as "SLURPgpi"; the signal sequence is set forth in SEQ ID NO: 184), and used to evaluate binding to the antibody. In a preferred aspect, the peptide having the amino acid sequence set forth in SEQ ID NO: 182 (SKSPSLVSLPT) has glycosylation modifications at either or both of the first and eighth serines. In a preferred embodiment, the glycosylation modification can be 2,3-sialyl T antigen (2,3-Sialyl T) or disialyl T antigen (DiSialyl T). In a most preferred embodiment, the antibody is a peptide having the amino acid sequence set forth in SEQ ID NO: 182 (SKSPSLVSLPT), wherein the peptide has a glycosylation modification at either or both of serine 1 and serine 8, and the glycosylation modification is 2,3-sialyl T antigen (2,3-Sialyl T) or disialyl T antigen (DiSialyl T).

[0022]

[0023] In certain aspects, a humanized antibody of the present disclosure may comprise a heavy chain variable region comprising a heavy chain CDR1 having the amino acid sequence set forth in SEQ ID NO: 37, a heavy chain CDR2 having the amino acid sequence set forth in SEQ ID NO: 43, and a heavy chain CDR3 having the amino acid sequence set forth in SEQ ID NO: 51; and a light chain variable region comprising a light chain CDR1 having the amino acid sequence set forth in SEQ ID NO: 62, a light chain CDR2 having the amino acid sequence set forth in SEQ ID NO: 75, and a light chain CDR3 having the amino acid sequence set forth in SEQ ID NO: 82.

[0024] In certain aspects, a humanized antibody of the present disclosure may comprise a heavy chain variable region comprising a heavy chain CDR1 having the amino acid sequence set forth in SEQ ID NO: 37, a heavy chain CDR2 having the amino acid sequence set forth in SEQ ID NO: 43, and a heavy chain CDR3 having the amino acid sequence set forth in SEQ ID NO: 51; and a light chain variable region comprising a light chain CDR1 having the amino acid sequence set forth in SEQ ID NO: 63, a light chain CDR2 having the amino acid sequence set forth in SEQ ID NO: 75, and a light chain CDR3 having the amino acid sequence set forth in SEQ ID NO: 82.

[0025] In one aspect, the humanized antibody of the present disclosure comprises a set of heavy chain CDR1-3 selected from any of the following (1A) to (8A): (1A) a heavy chain CDR1 having the amino acid sequence set forth in SEQ ID NO:89, a heavy chain CDR2 having the amino acid sequence set forth in SEQ ID NO:90, and a heavy chain CDR3 having the amino acid sequence set forth in SEQ ID NO:91; (2A) a heavy chain CDR1 having the amino acid sequence set forth in SEQ ID NO:92, a heavy chain CDR2 having the amino acid sequence set forth in SEQ ID NO:93, and a heavy chain CDR3 having the amino acid sequence set forth in SEQ ID NO:94; (3A) a heavy chain CDR1 having the amino acid sequence set forth in SEQ ID NO:95, a heavy chain CDR2 having the amino acid sequence set forth in SEQ ID NO:96, and a heavy chain CDR3 having the amino acid sequence set forth in SEQ ID NO:97; (4A) a heavy chain CDR1 having the amino acid sequence set forth in SEQ ID NO:98, a heavy chain CDR2 having the amino acid sequence set forth in SEQ ID NO:99, and a heavy chain CDR3 having the amino acid sequence set forth in SEQ ID NO:100; (5A) a heavy chain CDR1 having the amino acid sequence set forth in SEQ ID NO: 101, a heavy chain CDR2 having the amino acid sequence set forth in SEQ ID NO: 102, and a heavy chain CDR3 having the amino acid sequence set forth in SEQ ID NO: 103; (6A) a heavy chain CDR1 having the amino acid sequence set forth in SEQ ID NO: 104, a heavy chain CDR2 having the amino acid sequence set forth in SEQ ID NO: 105, and a heavy chain CDR3 having the amino acid sequence set forth in SEQ ID NO: 106; (7A) a heavy chain CDR1 having the amino acid sequence set forth in SEQ ID NO: 110, a heavy chain CDR2 having the amino acid sequence set forth in SEQ ID NO: 111, and a heavy chain CDR3 having the amino acid sequence set forth in SEQ ID NO: 112; or (8A) a heavy chain CDR1 having the amino acid sequence set forth in SEQ ID NO: 113, a heavy chain CDR2 having the amino acid sequence set forth in SEQ ID NO: 114, and a heavy chain CDR3 having the amino acid sequence set forth in SEQ ID NO: 115. The humanized antibody of the present disclosure may comprise a heavy chain variable region comprising heavy chain CDR1 to 3 of any of (1A) to (8A) above.

[0026] In one aspect, the humanized antibody of the present disclosure comprises a set of light chain CDR1-3 selected from any of the following (1B) to (18B): (1B) a light chain CDR1 having the amino acid sequence set forth in SEQ ID NO: 116, a light chain CDR2 having the amino acid sequence set forth in SEQ ID NO: 117, and a light chain CDR3 having the amino acid sequence set forth in SEQ ID NO: 118; (2B) a light chain CDR1 having the amino acid sequence set forth in SEQ ID NO: 119, a light chain CDR2 having the amino acid sequence set forth in SEQ ID NO: 120, and a light chain CDR3 having the amino acid sequence set forth in SEQ ID NO: 121; (3B) a light chain CDR1 having the amino acid sequence set forth in SEQ ID NO: 122, a light chain CDR2 having the amino acid sequence set forth in SEQ ID NO: 123, and a light chain CDR3 having the amino acid sequence set forth in SEQ ID NO: 124; (4B) a light chain CDR1 having the amino acid sequence set forth in SEQ ID NO: 128, a light chain CDR2 having the amino acid sequence set forth in SEQ ID NO: 129, and a light chain CDR3 having the amino acid sequence set forth in SEQ ID NO: 130; (5B) light chain CDR1 having the amino acid sequence set forth in SEQ ID NO: 131, light chain CDR2 having the amino acid sequence set forth in SEQ ID NO: 132, and light chain CDR3 having the amino acid sequence set forth in SEQ ID NO: 133; (6B) light chain CDR1 having the amino acid sequence set forth in SEQ ID NO: 134, light chain CDR2 having the amino acid sequence set forth in SEQ ID NO: 135, and light chain CDR3 having the amino acid sequence set forth in SEQ ID NO: 136; (7B) light chain CDR1 having the amino acid sequence set forth in SEQ ID NO: 137, light chain CDR2 having the amino acid sequence set forth in SEQ ID NO: 138, and light chain CDR3 having the amino acid sequence set forth in SEQ ID NO: 139; (8B) light chain CDR1 having the amino acid sequence set forth in SEQ ID NO: 140, light chain CDR2 having the amino acid sequence set forth in SEQ ID NO: 141, and light chain CDR3 having the amino acid sequence set forth in SEQ ID NO: 142; (9B) light chain CDR1 having the amino acid sequence set forth in SEQ ID NO: 143, light chain CDR2 having the amino acid sequence set forth in SEQ ID NO: 144, and light chain CDR3 having the amino acid sequence set forth in SEQ ID NO: 145; (10B) a light chain CDR1 having the amino acid sequence set forth in SEQ ID NO: 146, a light chain CDR2 having the amino acid sequence set forth in SEQ ID NO: 147, and a light chain CDR3 having the amino acid sequence set forth in SEQ ID NO: 148;(11B) light chain CDR1 having the amino acid sequence set forth in SEQ ID NO: 149, light chain CDR2 having the amino acid sequence set forth in SEQ ID NO: 150, and light chain CDR3 having the amino acid sequence set forth in SEQ ID NO: 151; (12B) light chain CDR1 having the amino acid sequence set forth in SEQ ID NO: 152, light chain CDR2 having the amino acid sequence set forth in SEQ ID NO: 153, and light chain CDR3 having the amino acid sequence set forth in SEQ ID NO: 154; (13B) light chain CDR1 having the amino acid sequence set forth in SEQ ID NO: 155, light chain CDR2 having the amino acid sequence set forth in SEQ ID NO: 156, and light chain CDR3 having the amino acid sequence set forth in SEQ ID NO: 157; (14B) light chain CDR1 having the amino acid sequence set forth in SEQ ID NO: 158, light chain CDR2 having the amino acid sequence set forth in SEQ ID NO: 159, and light chain CDR3 having the amino acid sequence set forth in SEQ ID NO: 160; (15B) light chain CDR1 having the amino acid sequence set forth in SEQ ID NO: 161, light chain CDR2 having the amino acid sequence set forth in SEQ ID NO: 162, and light chain CDR3 having the amino acid sequence set forth in SEQ ID NO: 163; (16B) a light chain CDR1 having the amino acid sequence set forth in SEQ ID NO: 173, a light chain CDR2 having the amino acid sequence set forth in SEQ ID NO: 174, and a light chain CDR3 having the amino acid sequence set forth in SEQ ID NO: 175; (17B) a light chain CDR1 having the amino acid sequence set forth in SEQ ID NO: 176, a light chain CDR2 having the amino acid sequence set forth in SEQ ID NO: 177, and a light chain CDR3 having the amino acid sequence set forth in SEQ ID NO: 178; or (18B) a light chain CDR1 having the amino acid sequence set forth in SEQ ID NO: 179, a light chain CDR2 having the amino acid sequence set forth in SEQ ID NO: 180, and a light chain CDR3 having the amino acid sequence set forth in SEQ ID NO: 181. The humanized antibody of the present disclosure may comprise a light chain variable region comprising any of the light chain CDR1 to 3 set forth in (1B) to (18B) above.

[0027] In one aspect, an antibody of the present disclosure may comprise a heavy chain variable region comprising a heavy chain CDR1 having the amino acid sequence set forth in SEQ ID NO: 37, a heavy chain CDR2 having the amino acid sequence set forth in SEQ ID NO: 43, and a heavy chain CDR3 having the amino acid sequence set forth in SEQ ID NO: 51; and a light chain variable region comprising any one of the sets of light chain CDR1 to CDR3 set forth in (1B) to (18B) above.

[0028] In one aspect, an antibody of the present disclosure may comprise a heavy chain variable region comprising the set of heavy chain CDR1 to CDR3 of any one of (1A) to (8A) above, and a light chain variable region comprising a light chain CDR1 having the amino acid sequence set forth in SEQ ID NO: 62, a light chain CDR2 having the amino acid sequence set forth in SEQ ID NO: 75, and a light chain CDR3 having the amino acid sequence set forth in SEQ ID NO: 82. Here, the light chain CDR1 may preferably have the amino acid sequence set forth in SEQ ID NO: 63.

[0029] In one aspect, an antibody of the present disclosure may comprise: a heavy chain variable region comprising any one of the heavy chain CDR1-CDR3 sets (1A) to (8A) above; and a light chain variable region comprising any one of the light chain CDR1-CDR3 sets (1B) to (18B) above.

[0030] In certain aspects, an antibody of the present disclosure may comprise: a heavy chain variable region comprising the set of heavy chain CDR1-3 of (1A) above; and a light chain variable region comprising the set of light chain CDR1-3 of any of (1B) to (18B) above. In a preferred aspect, the light chain variable region may comprise the set of light chain CDR1-3 of (1B) above. In a preferred aspect, the light chain variable region may comprise the set of light chain CDR1-3 of any of (2B) to (18B) above. In a preferred aspect, the light chain variable region may comprise the set of light chain CDR1-3 of any of (2B) to (10B) above. In a preferred aspect, the light chain variable region may comprise the set of light chain CDR1-3 of any of (2B) to (7B) and (10B) above (particularly (4B) or (10B)). In a preferred aspect, the light chain variable region may be (10B) above.

[0031] In certain aspects, an antibody of the present disclosure may comprise: a heavy chain variable region comprising the set of heavy chain CDR1-3 of (2A) above; and a light chain variable region comprising the set of light chain CDR1-3 of any of (1B) to (18B) above. In a preferred aspect, the light chain variable region may comprise the set of light chain CDR1-3 of (1B) above. In a preferred aspect, the light chain variable region may comprise the set of light chain CDR1-3 of any of (2B) to (18B) above. In a preferred aspect, the light chain variable region may comprise the set of light chain CDR1-3 of any of (2B) to (10B) above. In a preferred aspect, the light chain variable region may comprise the set of light chain CDR1-3 of any of (2B) to (7B) and (10B) above (particularly (4B) or (10B)). In a preferred aspect, the light chain variable region may be (10B) above.

[0032] In certain aspects, an antibody of the present disclosure may comprise: a heavy chain variable region comprising the set of heavy chain CDR1-3 of (3A) above; and a light chain variable region comprising the set of light chain CDR1-3 of any of (1B) to (18B) above. In a preferred aspect, the light chain variable region may comprise the set of light chain CDR1-3 of (1B) above. In a preferred aspect, the light chain variable region may comprise the set of light chain CDR1-3 of any of (2B) to (18B) above. In a preferred aspect, the light chain variable region may comprise the set of light chain CDR1-3 of any of (2B) to (10B) above. In a preferred aspect, the light chain variable region may comprise the set of light chain CDR1-3 of any of (2B) to (7B) and (10B) above (particularly (4B) or (10B)). In a preferred aspect, the light chain variable region may be (10B) above.

[0033] In certain aspects, an antibody of the present disclosure may comprise: a heavy chain variable region comprising the set of heavy chain CDR1-3 of (4A) above; and a light chain variable region comprising the set of light chain CDR1-3 of any of (1B) to (18B) above. In a preferred aspect, the light chain variable region may comprise the set of light chain CDR1-3 of (1B) above. In a preferred aspect, the light chain variable region may comprise the set of light chain CDR1-3 of any of (2B) to (18B) above. In a preferred aspect, the light chain variable region may comprise the set of light chain CDR1-3 of any of (2B) to (10B) above. In a preferred aspect, the light chain variable region may comprise the set of light chain CDR1-3 of any of (2B) to (7B) and (10B) above (particularly (4B) or (10B)). In a preferred aspect, the light chain variable region may be (10B) above.

[0034] In certain aspects, an antibody of the present disclosure may comprise: a heavy chain variable region comprising the set of heavy chain CDR1-3 of (5A) above; and a light chain variable region comprising the set of light chain CDR1-3 of any of (1B) to (18B) above. In a preferred aspect, the light chain variable region may comprise the set of light chain CDR1-3 of (1B) above. In a preferred aspect, the light chain variable region may comprise the set of light chain CDR1-3 of any of (2B) to (18B) above. In a preferred aspect, the light chain variable region may comprise the set of light chain CDR1-3 of any of (2B) to (10B) above. In a preferred aspect, the light chain variable region may comprise the set of light chain CDR1-3 of any of (2B) to (7B) and (10B) above (particularly any of (4B), (7B), (10B), or (14B) to (16B)). In a preferred embodiment, the light chain variable region may be (10B) above.

[0035] In certain aspects, an antibody of the present disclosure may comprise: a heavy chain variable region comprising the set of heavy chain CDR1-3 of (6A) above; and a light chain variable region comprising the set of light chain CDR1-3 of any of (1B) to (18B) above. In a preferred aspect, the light chain variable region may comprise the set of light chain CDR1-3 of (1B) above. In a preferred aspect, the light chain variable region may comprise the set of light chain CDR1-3 of any of (2B) to (18B) above. In a preferred aspect, the light chain variable region may comprise the set of light chain CDR1-3 of any of (2B) to (10B) above. In a preferred aspect, the light chain variable region may comprise the set of light chain CDR1-3 of any of (2B) to (7B) and (10B) above (particularly any of (4B), (7B), (10B), or (14B) to (16B)). In a preferred embodiment, the light chain variable region may be (10B) above.

[0036] In certain aspects, an antibody of the present disclosure may comprise: a heavy chain variable region comprising the set of heavy chain CDR1-3 of (7A) above; and a light chain variable region comprising the set of light chain CDR1-3 of any of (1B) to (18B) above. In a preferred aspect, the light chain variable region may comprise the set of light chain CDR1-3 of (1B) above. In a preferred aspect, the light chain variable region may comprise the set of light chain CDR1-3 of any of (2B) to (18B) above. In a preferred aspect, the light chain variable region may comprise the set of light chain CDR1-3 of any of (2B) to (10B) above. In a preferred aspect, the light chain variable region may comprise the set of light chain CDR1-3 of any of (2B) to (7B) and (10B) above (particularly (4B) or (10B)). In a preferred aspect, the light chain variable region may be (10B) above.

[0037] In certain aspects, an antibody of the present disclosure may comprise: a heavy chain variable region comprising the set of heavy chain CDR1-3 of (8A) above; and a light chain variable region comprising the set of light chain CDR1-3 of any of (1B) to (18B) above. In a preferred aspect, the light chain variable region may comprise the set of light chain CDR1-3 of (1B) above. In a preferred aspect, the light chain variable region may comprise the set of light chain CDR1-3 of any of (2B) to (18B) above. In a preferred aspect, the light chain variable region may comprise the set of light chain CDR1-3 of any of (2B) to (10B) above. In a preferred aspect, the light chain variable region may comprise the set of light chain CDR1-3 of any of (2B) to (7B) and (10B) above (particularly (4B) or (10B)). In a preferred aspect, the light chain variable region may be (10B) above.

[0038] In a preferred aspect, in the antibody of the present disclosure, the variable region of the antibody into which the heavy chain CDR1-3 and light chain CDR1-3 are grafted may be the variable region of a human IgG1 antibody. In a preferred aspect, in the antibody of the present disclosure, the variable region of the antibody into which the heavy chain CDR1-3 and light chain CDR1-3 are grafted may be the variable region of a human IgG2 antibody. In a preferred aspect, in the antibody of the present disclosure, the variable region of the antibody into which the heavy chain CDR1-3 and light chain CDR1-3 are grafted may be the variable region of a human IgG3 antibody. In a preferred aspect, in the antibody of the present disclosure, the variable region of the antibody into which the heavy chain CDR1-3 and light chain CDR1-3 are grafted may be the variable region of a human IgG4 antibody.

[0039] In a preferred embodiment, the Fc region (i.e., heavy chain constant region 2 and / or 3) of an antibody of the present disclosure may be the Fc region of a human IgG1 antibody. In a preferred embodiment, the Fc region (i.e., heavy chain constant region 2 and / or 3) of an antibody of the present disclosure may be the Fc region of a human IgG2 antibody. In a preferred embodiment, the Fc region (i.e., heavy chain constant region 2 and / or 3) of an antibody of the present disclosure may be the Fc region of a human IgG3 antibody. In a preferred embodiment, the Fc region (i.e., heavy chain constant region 2 and / or 3) of an antibody of the present disclosure may be the Fc region of a human IgG4 antibody.

[0040] In one aspect, in an antibody of the present disclosure, the heavy chain variable region may have framework region 1 having the amino acid sequence set forth in SEQ ID NO: 32, framework region 2 having the amino acid sequence set forth in SEQ ID NO: 40, framework region 3 having the amino acid sequence set forth in SEQ ID NO: 46, and framework region 4 having the amino acid sequence set forth in SEQ ID NO: 54.

[0041] In a preferred embodiment, the heavy chain variable region of an antibody of the present disclosure has framework region 1 having the amino acid sequence set forth in SEQ ID NO: 33, framework region 2 having the amino acid sequence set forth in SEQ ID NO: 40, framework region 3 having the amino acid sequence set forth in SEQ ID NO: 46, and framework region 4 having the amino acid sequence set forth in SEQ ID NO: 54. Here, in SEQ ID NO: 46, X1 is A, X3 is T, X5 is E, X6 is R, and X7 is T, and in SEQ ID NO: 54, X1 can be V, X3 is T, X4 is Q or E, and X5 can be P.

[0042] In one aspect, the heavy chain variable region of an antibody of the present disclosure has framework region 1 having the amino acid sequence set forth in SEQ ID NO: 33, framework region 2 having the amino acid sequence set forth in SEQ ID NO: 42, framework region 3 having the amino acid sequence set forth in SEQ ID NO: 48, and framework region 4 having the amino acid sequence set forth in SEQ ID NO: 59.

[0043] In one aspect, in an antibody of the present disclosure, the light chain variable region may have framework region 1 having the amino acid sequence set forth in SEQ ID NO:57, framework region 2 having the amino acid sequence set forth in SEQ ID NO:72, framework region 3 having the amino acid sequence set forth in SEQ ID NO:79, and framework region 4 having the amino acid sequence set forth in SEQ ID NO:86.

[0044] In one aspect, in an antibody of the present disclosure, the light chain variable region may have framework region 1 having the amino acid sequence set forth in SEQ ID NO:61, framework region 2 having the amino acid sequence set forth in SEQ ID NO:74, framework region 3 having the amino acid sequence set forth in SEQ ID NO:81, and framework region 4 having the amino acid sequence set forth in SEQ ID NO:88.

[0045] In certain aspects, an antibody of the present disclosure may comprise a heavy chain variable region selected from the group consisting of SEQ ID NOs: 1-6, 8, and 9, and a light chain variable region selected from the group consisting of SEQ ID NOs: 10, 12-15, 17-21, 23-25, and 29 to 31. In certain aspects, an antibody of the present disclosure may comprise a heavy chain variable region selected from the group consisting of SEQ ID NOs: 2, 4-6, 8, and 9, and a light chain variable region selected from the group consisting of SEQ ID NOs: 14, 15, 17-21, 23-25, and 29 to 31. In a preferred aspect, an antibody of the present disclosure may comprise a heavy chain variable region set forth in SEQ ID NO: 6, and a light chain variable region set forth in SEQ ID NO: 21.

[0046] The antibodies or antigen-binding fragments thereof of the present disclosure may include antibodies or antigen-binding fragments thereof having mutations selected from the group consisting of insertion, deletion, addition, and substitution of one to several amino acids. In one embodiment, an antibody or antigen-binding fragment thereof is provided that comprises at least one CDR, at least two, at least three, or more CDRs that are substantially identical to at least one CDR, at least two, at least three, or more CDRs in an antibody or antigen-binding fragment thereof of the present disclosure. In another embodiment, an antibody having at least two, three, four, five, or six CDRs that are substantially identical to at least two, three, four, five, or six CDRs in or derived from an antibody or antigen-binding fragment thereof of the present disclosure is included. In some embodiments, at least one, two, three, four, five, or six CDRs are at least about 85%, 86%, 87%, 88%, 89%, 90%, 95%, 96%, 97%, 98%, or 99% identical to at least one, two, or three CDRs in an antibody or antigen-binding fragment thereof of the present disclosure. In some embodiments, the at least one, two, three, four, five, or six CDRs comprise at least one insertion, deletion, addition, or substitution in at least one, two, three, four, five, or six CDRs in or derived from an antibody or antigen-binding fragment thereof of the present disclosure. Antibodies or antigen-binding fragments thereof of the present disclosure may include antibodies or antigen-binding fragments thereof that have 80% or more, 85% or more, 90% or more, or 95% or more amino acid sequence identity and have the antigen specificity of the antibody. The antibodies or antigen-binding fragments thereof of the present disclosure may include, for example, antibodies or antigen-binding fragments thereof that have 80% or more, 85% or more, 90% or more, or 95% or more amino acid sequence identity in the framework regions with the antibodies disclosed above and have the antigen specificity of the antibodies. The antibodies or antigen-binding fragments thereof of the present disclosure may include, for example, antibodies or antigen-binding fragments thereof that have mutations in the framework regions selected from the group consisting of insertion, deletion, addition, and substitution of one to several amino acids in the antibodies disclosed above.

[0047] In a preferred embodiment, the humanized IgG antibody may be an antibody that binds to a peptide having the amino acid sequence set forth in SEQ ID NO: 182 (SKSPSLVSLPT). The partial peptide may be, for example, a peptide produced by mesothelioma cells (e.g., ACC-MESO4 cell line). The peptide may be obtained as a fusion protein by linking it to the N-terminus of a protein in which a GPI anchor signal is attached to the N-terminus of human SLURP1, and used to evaluate binding to the antibody. In a preferred embodiment, the human antibody may be any of the human antibodies described above.

[0048] In a preferred embodiment, the humanized IgG antibody may be any of the humanized antibodies described above. In a preferred embodiment, the antibody of the present disclosure may comprise a heavy chain variable region set forth in SEQ ID NO:6 and a light chain variable region set forth in SEQ ID NO:21.

[0049] Non-limiting examples of IgG antibody heavy chain constant regions include the heavy chain constant regions of IgG1, IgG2, IgG3, IgG4, and IgG4PE. The heavy chain constant regions of IgG1, IgG2, IgG4, and IgG4PE are preferred, with the heavy chain constant regions of IgG1 and IgG4PE being more preferred, and the heavy chain constant region of IgG4PE being even more preferred. The hinge region of IgG1 may have, for example, the amino acid sequence of SEQ ID NO: 185. The hinge region of IgG4 may have, for example, the amino acid sequence of SEQ ID NO: 186. The hinge region of IgG4PE may have, for example, the amino acid sequence of SEQ ID NO: 187. The CH2 region of IgG1 may have, for example, the amino acid sequence of SEQ ID NO: 188. The CH2 regions of IgG4 and IgG4PE may have, for example, the amino acid sequence of SEQ ID NO: 189.

[0050] Non-limiting examples of the light chain constant region of an IgG antibody include the light chain constant region of a kappa chain or a lambda chain, and may be, for example, a light chain constant region of a kappa chain.

[0051] The humanized antibodies of the present disclosure may or may not have internalizing activity for therapeutic and diagnostic purposes.

[0052] <Method of treating mesothelioma in a subject> According to the present disclosure, there is provided a method of treating mesothelioma in a subject. According to the present disclosure, the method includes administering to the subject an effective amount of an antibody of the present disclosure. The subject may have mesothelioma. The subject may have been diagnosed with mesothelioma.

[0053] Administration can be performed parenterally (e.g., intraperitoneally, intrathoracically, intratumorally, intravenously, etc.). The dosage can be determined appropriately by a physician taking into consideration the condition, weight, sex, and age of the subject. Administration can be a single dose or multiple doses.

[0054] The present disclosure provides an antibody of the present disclosure for use in the above method.

[0055] In certain aspects, the antibodies of the present disclosure may have antibody-dependent cellular cytotoxicity (ADCC) activity and / or complement-dependent cytotoxicity (CDC) activity. ADCC activity refers to the activity of Fcγ receptor-bearing cells (effector cells) binding to the Fc portion of an antibody of the present invention via Fcγ receptors, thereby damaging the target cells, when the antibody binds to a cell surface antigen on the target cell.

[0056] ADCC activity can be determined by mixing target cells (e.g., mesothelioma cells) expressing HEG1 with effector cells and the antibody of the present invention and measuring the degree of ADCC. Examples of effector cells that can be used include mouse splenocytes and monocyte nuclei isolated from human peripheral blood or bone marrow. Examples of target cells that can be used include mesothelioma cells expressing HEG1. Target cells are pre-labeled with 51Cr or the like, and then incubated with the antibody of the present invention. An appropriate ratio of effector cells to target cells is then added and incubated. After incubation, the supernatant is collected and assayed by counting the label in the supernatant.

[0057] CDC activity refers to the cytotoxic activity mediated by the complement system. CDC activity can be measured by using complement instead of effector cells in the above-mentioned ADCC activity test.

[0058] In some embodiments, the antibodies of the present disclosure may themselves have a tumor growth inhibitory effect. Tumor growth inhibitory activity can be measured using tumor model animals. For example, a tumor is subcutaneously implanted into a mouse, and the antibody of the present invention is administered. The tumor growth inhibitory effect can be measured by comparing the volume of tumor tissue between a non-administered group and an administered group. The tumor growth inhibitory activity of the present invention may result from inhibiting the proliferation of individual cells or from inducing cell death.

[0059] In certain aspects, the antibody of the present disclosure may be linked to a cytotoxic agent (particularly a chemotherapeutic agent) via a linker. Thus, the present disclosure can provide an antibody-drug conjugate comprising the antibody of the present disclosure and a cytotoxic agent, wherein the antibody and the cytotoxic agent are linked via a linker. Cytotoxic agents include chemotherapeutic agents (e.g., anticancer agents such as commercially available anticancer drugs, e.g., auristatins (auristatin E, auristatin F phenylenediamine (AFP), monomethyl auristatin E, monomethyl auristatin F, and derivatives thereof), maytansinoids DM1 and DM4, and derivatives thereof), camptothecins (SN-38, irinotecan, lutecan, DB67, BMP1350, ST1481, CKD602, topotecan, and exatecan, and derivatives thereof), DNA minor groove binders (enediynes, lexitropsins, duocarmycins, and derivatives thereof), taxanes (paclitaxel and docetaxel, and derivatives thereof), polyketides (discodermolide and derivatives thereof), anthraquinones (mitoxantrone and derivatives thereof), benzodiazepines (pyroxenic acid, benzodiazepines), and the like. Examples of cytotoxic agents that can be used in the ADCs of the present invention include benzodiazepines (indolinobenzodiazepines, indolinobenzodiazepines, and oxazolidinobenzodiazepines and their derivatives), vinca alkaloids (vincristine, vinblastine, vindesine, and vinorelbine and their derivatives), doxorubicins (doxorubicin, morpholino-doxorubicin, and cyanomorpholino-doxorubicin and their derivatives), cardiac glycosides (digitoxin and its derivatives), calecchiamicin, epothilones, cryptophycins, cemadotin, rhizoxin, netropsin, combretastatin, eleutherobin, etoposide, T67 (Tularik), and nocodazole), and toxins (e.g., diphtheria toxin A, pseudomonas endotoxin, ricin, saporin, etc.), which can be used as cytotoxic agents in the ADCs of the present invention. The cytotoxic agent may be a pharmaceutically acceptable salt, solvate (eg, hydrate), ester, or prodrug of the above-mentioned cytotoxic agent.

[0060] The linker can be a non-cleavable linker or a cleavable linker (eg, containing a valine-citrulline dipeptide).

[0061] The present disclosure provides a composition comprising an antibody of the present disclosure. The present disclosure discloses a pharmaceutical composition comprising an antibody of the present disclosure. The pharmaceutical composition of the present disclosure can be used to treat mesothelioma. The present disclosure also provides a composition comprising an antibody-drug conjugate of the present disclosure. The present disclosure discloses a pharmaceutical composition comprising an antibody-drug conjugate of the present disclosure. The pharmaceutical composition of the present disclosure can be used to treat mesothelioma.

[0062] The pharmaceutical composition of the present disclosure may further comprise a pharmaceutically acceptable carrier, excipient, and / or additive. Examples of carriers and additives include, but are not limited to, water, saline, phosphate buffer, dextrose, glycerol, ethanol, and other pharmaceutically acceptable organic solvents, collagen, polyvinyl alcohol, polyvinylpyrrolidone, carboxyvinyl polymer, sodium carboxymethylcellulose, sodium polyacrylate, sodium alginate, water-soluble dextran, sodium carboxymethyl starch, pectin, methylcellulose, ethylcellulose, xanthan gum, gum arabic, casein, agar, polyethylene glycol, diglycerin, glycerin, propylene glycol, petrolatum, paraffin, stearyl alcohol, stearic acid, human serum albumin, mannitol, sorbitol, lactose, surfactants, and the like.

[0063] The pharmaceutical composition of the present invention can be in various forms, for example, a liquid preparation (e.g., an injection). A preferred embodiment is an injection or infusion preparation, which is preferably administered parenterally (e.g., intravenously, transdermally, subcutaneously, intradermally, intraperitoneally, intrathoracically, intramuscularly, or intratumorally).

[0064] The present invention will be explained in more detail with reference to the following examples, but the scope of the present invention is not limited to these examples.

[0065] [Production Example 1] Production of humanized antibodies Humanized antibodies were designed using standard methods to contain the amino acid sequences of various variable regions to which a mouse antibody-derived signal sequence had been added, and the amino acid sequence of a human IgG1 constant region. The nucleotide sequences encoding the designed humanized antibodies were converted to a codon usage suitable for expression in Chinese hamster ovary (CHO) cells. A Kozak sequence was added to the resulting nucleotide sequence and the start codon of the signal sequence. A stop codon was added to the C-terminus of the constant region, and restriction enzyme sites were added upstream and downstream of the Kozak sequence. A mammalian cell expression plasmid (pcDNA3.1) was then digested with restriction enzymes and ligated to incorporate the above sequence into the plasmid. The resulting H chain expression plasmids and L chain expression plasmids were combined to form one H chain and one L chain, and expressed in an ExpiCHO Expression System (ThermoFisher Scientific) or in RK13 cells. The resulting proteins were recovered from the culture supernatant using HiTrap protein G (1 mL) (Cytiba), eluted with 0.1 M glycine buffer (pH 2.8), and purified by dialysis against PBS.

[0066] Humanized antibodies were obtained using the above method. The antibody activity of each obtained antibody was measured by ELISA using 7.62EGF as the antigen. 7.62EGF is a secreted protein with an antibody epitope region linked to the N-terminus of the EGF domain region of HEG1 and a His tag linked to the C-terminus. When produced in 293H cells, it is sialylated and glycosylated, allowing it to be recognized by the antibody. 7.62EGF purified from the culture supernatant of constitutively expressing cells was adsorbed onto an ELISA plate and blocked with 1% BSA. Culture supernatant of RK13 cells transfected with a humanized antibody gene was added to the plate and allowed to react at room temperature for 3 hours. After washing with 20 mM Tris-buffered saline containing 0.1% Tween 20, a secondary antibody (horseradish peroxidase-labeled goat anti-human IgG, Fc gamma fragment specific) was added and allowed to react for 90 minutes. After washing with 20 mM Tris-buffered saline containing 0.1% Tween 20, 1-Step Ultra TMB-ELISA Substrate Solution (Thermo Fisher Scientific) was added. The reaction was stopped with 2 M sulfuric acid, and the absorbance at 450 nm was measured. The results are shown in Figures 1 to 6. Antigen binding activity was observed in antibodies with a combination comprising the amino acid sequence shown in Table 1 as the heavy chain and the amino acid sequence shown in Table 2 as the light chain.

[0067]

[0068]

[0069] [Production Example 2] Production of humanized SKM9-2 using different signal sequences Among the antibodies obtained in Production Example 1, an antibody with high antigen-binding activity and a large amount of human-derived sequences (heavy chain: zuH3c, light chain: zuL5g) was selected as a representative humanized SKM9-2, and signal sequences were examined. An antibody having zuH3c as the heavy chain amino acid sequence and zuL5g as the light chain amino acid sequence was produced in the same manner as in Production Example 1, except that the signal sequences shown in Table 3 were used. The results of antibody production yields are shown in Figure 7. No significant differences in antibody production yields were observed regardless of the signal sequence used, but the antibody production yield tended to be slightly higher when HV1 (SEQ ID NO: 221) was used as the heavy chain signal sequence and KL1 (SEQ ID NO: 227) was used as the light chain signal sequence.

[0070]

[0071] [Production Example 3] Production of Humanized Antibodies with Different Subtypes Humanized antibodies were produced in the same manner as in Production Example 1, except that the heavy chain variable region used was zuH3c (SEQ ID NO: 6) linked to the human IgG constant region (CH1-CH3), and the light chain variable region used was zuL5g linked to the human kappa chain constant region (CL). The IgG4PE variant (S228P, L235E) had two amino acid residues near the hinge altered. Figure 8 shows the results of SDS-PAGE of each antibody obtained. Figure 9 shows the results of Biacore X100 analysis of binding to the synthetic glycopeptide epitope represented by the formula below, and flow cytometry analysis of binding to the mesothelioma cell line NCI-H226. For Biacore, a His-tagged synthetic glycopeptide was used as the ligand, and the antibody was used as the analyte. A Ni2+-conjugated Sensor Chip NTA was used as the sensor chip. Affinity calculations were performed according to the Biacore X100 protocol. For flow cytometry, purified antibodies were used as primary antibodies at 10 μg / mL, and FITC-goat anti-human IgG F(ab)'2 was used as secondary antibodies at 25 μg / mL. The black line represents the negative control without primary antibodies, and the red line represents the control with each primary antibody added. No significant differences were observed between the antibodies in either Biacore or flow cytometry.

[0072]

[0073]

Claims

1. An antibody or antigen-binding fragment thereof, the antibody is a humanized antibody capable of binding to human HEG1 protein expressed on mesothelioma cells; The antibody or antigen-binding fragment thereof comprises a heavy chain variable region including a heavy chain CDR1 having the amino acid sequence set forth in SEQ ID NO: 37, a heavy chain CDR2 having the amino acid sequence set forth in SEQ ID NO: 43, and a heavy chain CDR3 having the amino acid sequence set forth in SEQ ID NO: 51, and a light chain variable region including a light chain CDR1 having the amino acid sequence set forth in SEQ ID NO: 62, a light chain CDR2 having the amino acid sequence set forth in SEQ ID NO: 75, and a light chain CDR3 having the amino acid sequence set forth in SEQ ID NO:

82.

2. The antibody or antigen-binding fragment thereof according to claim 1, An antibody or antigen-binding fragment thereof, comprising a heavy chain variable region comprising a heavy chain CDR1 having the amino acid sequence set forth in SEQ ID NO: 37, a heavy chain CDR2 having the amino acid sequence set forth in SEQ ID NO: 43, and a heavy chain CDR3 having the amino acid sequence set forth in SEQ ID NO: 51, and a light chain variable region comprising a light chain CDR1 having the amino acid sequence set forth in SEQ ID NO: 63, a light chain CDR2 having the amino acid sequence set forth in SEQ ID NO: 75, and a light chain CDR3 having the amino acid sequence set forth in SEQ ID NO:

82.

3. 3. The antibody or antigen-binding fragment thereof according to claim 1 or 2, The heavy chain variable region is (1) a heavy chain CDR1 having the amino acid sequence set forth in SEQ ID NO:89, a heavy chain CDR2 having the amino acid sequence set forth in SEQ ID NO:90, and a heavy chain CDR3 having the amino acid sequence set forth in SEQ ID NO:91; (2) a heavy chain CDR1 having the amino acid sequence set forth in SEQ ID NO: 92, a heavy chain CDR2 having the amino acid sequence set forth in SEQ ID NO: 93, and a heavy chain CDR3 having the amino acid sequence set forth in SEQ ID NO: 94; (3) a heavy chain CDR1 having the amino acid sequence set forth in SEQ ID NO: 95, a heavy chain CDR2 having the amino acid sequence set forth in SEQ ID NO: 96, and a heavy chain CDR3 having the amino acid sequence set forth in SEQ ID NO: 97; (4) a heavy chain CDR1 having the amino acid sequence set forth in SEQ ID NO: 98, a heavy chain CDR2 having the amino acid sequence set forth in SEQ ID NO: 99, and a heavy chain CDR3 having the amino acid sequence set forth in SEQ ID NO: 100; (5) a heavy chain CDR1 having the amino acid sequence set forth in SEQ ID NO: 101, a heavy chain CDR2 having the amino acid sequence set forth in SEQ ID NO: 102, and a heavy chain CDR3 having the amino acid sequence set forth in SEQ ID NO: 103; (6) a heavy chain CDR1 having the amino acid sequence set forth in SEQ ID NO: 104, a heavy chain CDR2 having the amino acid sequence set forth in SEQ ID NO: 105, and a heavy chain CDR3 having the amino acid sequence set forth in SEQ ID NO: 106; (7) a heavy chain CDR1 having the amino acid sequence set forth in SEQ ID NO: 110, a heavy chain CDR2 having the amino acid sequence set forth in SEQ ID NO: 111, and a heavy chain CDR3 having the amino acid sequence set forth in SEQ ID NO: 112; or (8) A heavy chain CDR1 having the amino acid sequence set forth in SEQ ID NO: 113, a heavy chain CDR2 having the amino acid sequence set forth in SEQ ID NO: 114, and a heavy chain CDR3 having the amino acid sequence set forth in SEQ ID NO:

115. An antibody or an antigen-binding fragment thereof comprising:

4. 3. The antibody or antigen-binding fragment thereof according to claim 1 or 2, The light chain variable region is (1) a light chain CDR1 having the amino acid sequence set forth in SEQ ID NO: 116, a light chain CDR2 having the amino acid sequence set forth in SEQ ID NO: 117, and a light chain CDR3 having the amino acid sequence set forth in SEQ ID NO: 118; (2) a light chain CDR1 having the amino acid sequence set forth in SEQ ID NO: 119, a light chain CDR2 having the amino acid sequence set forth in SEQ ID NO: 120, and a light chain CDR3 having the amino acid sequence set forth in SEQ ID NO: 121; (3) a light chain CDR1 having the amino acid sequence set forth in SEQ ID NO: 122, a light chain CDR2 having the amino acid sequence set forth in SEQ ID NO: 123, and a light chain CDR3 having the amino acid sequence set forth in SEQ ID NO: 124; (4) a light chain CDR1 having the amino acid sequence set forth in SEQ ID NO: 128, a light chain CDR2 having the amino acid sequence set forth in SEQ ID NO: 129, and a light chain CDR3 having the amino acid sequence set forth in SEQ ID NO: 130; (5) a light chain CDR1 having the amino acid sequence set forth in SEQ ID NO: 131, a light chain CDR2 having the amino acid sequence set forth in SEQ ID NO: 132, and a light chain CDR3 having the amino acid sequence set forth in SEQ ID NO: 133; (6) a light chain CDR1 having the amino acid sequence set forth in SEQ ID NO: 134, a light chain CDR2 having the amino acid sequence set forth in SEQ ID NO: 135, and a light chain CDR3 having the amino acid sequence set forth in SEQ ID NO: 136; (7) a light chain CDR1 having the amino acid sequence set forth in SEQ ID NO: 137, a light chain CDR2 having the amino acid sequence set forth in SEQ ID NO: 138, and a light chain CDR3 having the amino acid sequence set forth in SEQ ID NO: 139; (8) a light chain CDR1 having the amino acid sequence set forth in SEQ ID NO: 140, a light chain CDR2 having the amino acid sequence set forth in SEQ ID NO: 141, and a light chain CDR3 having the amino acid sequence set forth in SEQ ID NO: 142; (9) a light chain CDR1 having the amino acid sequence set forth in SEQ ID NO: 143, a light chain CDR2 having the amino acid sequence set forth in SEQ ID NO: 144, and a light chain CDR3 having the amino acid sequence set forth in SEQ ID NO: 145; (10) a light chain CDR1 having the amino acid sequence set forth in SEQ ID NO: 146, a light chain CDR2 having the amino acid sequence set forth in SEQ ID NO: 147, and a light chain CDR3 having the amino acid sequence set forth in SEQ ID NO: 148; (11) a light chain CDR1 having the amino acid sequence set forth in SEQ ID NO: 149, a light chain CDR2 having the amino acid sequence set forth in SEQ ID NO: 150, and a light chain CDR3 having the amino acid sequence set forth in SEQ ID NO: 151; (12) a light chain CDR1 having the amino acid sequence set forth in SEQ ID NO: 152, a light chain CDR2 having the amino acid sequence set forth in SEQ ID NO: 153, and a light chain CDR3 having the amino acid sequence set forth in SEQ ID NO: 154; (13) a light chain CDR1 having the amino acid sequence set forth in SEQ ID NO: 155, a light chain CDR2 having the amino acid sequence set forth in SEQ ID NO: 156, and a light chain CDR3 having the amino acid sequence set forth in SEQ ID NO: 157; (14) a light chain CDR1 having the amino acid sequence set forth in SEQ ID NO: 158, a light chain CDR2 having the amino acid sequence set forth in SEQ ID NO: 159, and a light chain CDR3 having the amino acid sequence set forth in SEQ ID NO: 160; (15) a light chain CDR1 having the amino acid sequence set forth in SEQ ID NO: 161, a light chain CDR2 having the amino acid sequence set forth in SEQ ID NO: 162, and a light chain CDR3 having the amino acid sequence set forth in SEQ ID NO: 163; (16) a light chain CDR1 having the amino acid sequence set forth in SEQ ID NO: 173, a light chain CDR2 having the amino acid sequence set forth in SEQ ID NO: 174, and a light chain CDR3 having the amino acid sequence set forth in SEQ ID NO: 175; (17) A light chain CDR1 having the amino acid sequence set forth in SEQ ID NO: 176, a light chain CDR2 having the amino acid sequence set forth in SEQ ID NO: 177, and a light chain CDR3 having the amino acid sequence set forth in SEQ ID NO: 178; or (18) A light chain CDR1 having the amino acid sequence set forth in SEQ ID NO: 179, a light chain CDR2 having the amino acid sequence set forth in SEQ ID NO: 180, and a light chain CDR3 having the amino acid sequence set forth in SEQ ID NO:

181. An antibody or an antigen-binding fragment thereof comprising:

5. (1) a heavy chain CDR1 having the amino acid sequence set forth in SEQ ID NO:89, a heavy chain CDR2 having the amino acid sequence set forth in SEQ ID NO:90, and a heavy chain CDR3 having the amino acid sequence set forth in SEQ ID NO:91; (2) a heavy chain CDR1 having the amino acid sequence set forth in SEQ ID NO: 92, a heavy chain CDR2 having the amino acid sequence set forth in SEQ ID NO: 93, and a heavy chain CDR3 having the amino acid sequence set forth in SEQ ID NO: 94; (3) a heavy chain CDR1 having the amino acid sequence set forth in SEQ ID NO: 95, a heavy chain CDR2 having the amino acid sequence set forth in SEQ ID NO: 96, and a heavy chain CDR3 having the amino acid sequence set forth in SEQ ID NO: 97; (4) a heavy chain CDR1 having the amino acid sequence set forth in SEQ ID NO: 98, a heavy chain CDR2 having the amino acid sequence set forth in SEQ ID NO: 99, and a heavy chain CDR3 having the amino acid sequence set forth in SEQ ID NO: 100; (5) a heavy chain CDR1 having the amino acid sequence set forth in SEQ ID NO: 101, a heavy chain CDR2 having the amino acid sequence set forth in SEQ ID NO: 102, and a heavy chain CDR3 having the amino acid sequence set forth in SEQ ID NO: 103; (6) a heavy chain CDR1 having the amino acid sequence set forth in SEQ ID NO: 104, a heavy chain CDR2 having the amino acid sequence set forth in SEQ ID NO: 105, and a heavy chain CDR3 having the amino acid sequence set forth in SEQ ID NO: 106; (7) a heavy chain CDR1 having the amino acid sequence set forth in SEQ ID NO: 110, a heavy chain CDR2 having the amino acid sequence set forth in SEQ ID NO: 111, and a heavy chain CDR3 having the amino acid sequence set forth in SEQ ID NO: 112; or (8) A heavy chain CDR1 having the amino acid sequence set forth in SEQ ID NO: 113, a heavy chain CDR2 having the amino acid sequence set forth in SEQ ID NO: 114, and a heavy chain CDR3 having the amino acid sequence set forth in SEQ ID NO:

115. and a heavy chain variable region comprising: (1) a light chain CDR1 having the amino acid sequence set forth in SEQ ID NO: 116, a light chain CDR2 having the amino acid sequence set forth in SEQ ID NO: 117, and a light chain CDR3 having the amino acid sequence set forth in SEQ ID NO: 118; (2) a light chain CDR1 having the amino acid sequence set forth in SEQ ID NO: 119, a light chain CDR2 having the amino acid sequence set forth in SEQ ID NO: 120, and a light chain CDR3 having the amino acid sequence set forth in SEQ ID NO: 121; (3) a light chain CDR1 having the amino acid sequence set forth in SEQ ID NO: 122, a light chain CDR2 having the amino acid sequence set forth in SEQ ID NO: 123, and a light chain CDR3 having the amino acid sequence set forth in SEQ ID NO: 124; (4) a light chain CDR1 having the amino acid sequence set forth in SEQ ID NO: 128, a light chain CDR2 having the amino acid sequence set forth in SEQ ID NO: 129, and a light chain CDR3 having the amino acid sequence set forth in SEQ ID NO: 130; (5) a light chain CDR1 having the amino acid sequence set forth in SEQ ID NO: 131, a light chain CDR2 having the amino acid sequence set forth in SEQ ID NO: 132, and a light chain CDR3 having the amino acid sequence set forth in SEQ ID NO: 133; (6) a light chain CDR1 having the amino acid sequence set forth in SEQ ID NO: 134, a light chain CDR2 having the amino acid sequence set forth in SEQ ID NO: 135, and a light chain CDR3 having the amino acid sequence set forth in SEQ ID NO: 136; (7) a light chain CDR1 having the amino acid sequence set forth in SEQ ID NO: 137, a light chain CDR2 having the amino acid sequence set forth in SEQ ID NO: 138, and a light chain CDR3 having the amino acid sequence set forth in SEQ ID NO: 139; (8) a light chain CDR1 having the amino acid sequence set forth in SEQ ID NO: 140, a light chain CDR2 having the amino acid sequence set forth in SEQ ID NO: 141, and a light chain CDR3 having the amino acid sequence set forth in SEQ ID NO: 142; (9) a light chain CDR1 having the amino acid sequence set forth in SEQ ID NO: 143, a light chain CDR2 having the amino acid sequence set forth in SEQ ID NO: 144, and a light chain CDR3 having the amino acid sequence set forth in SEQ ID NO: 145; (10) a light chain CDR1 having the amino acid sequence set forth in SEQ ID NO: 146, a light chain CDR2 having the amino acid sequence set forth in SEQ ID NO: 147, and a light chain CDR3 having the amino acid sequence set forth in SEQ ID NO: 148; (11) a light chain CDR1 having the amino acid sequence set forth in SEQ ID NO: 149, a light chain CDR2 having the amino acid sequence set forth in SEQ ID NO: 150, and a light chain CDR3 having the amino acid sequence set forth in SEQ ID NO: 151; (12) a light chain CDR1 having the amino acid sequence set forth in SEQ ID NO: 152, a light chain CDR2 having the amino acid sequence set forth in SEQ ID NO: 153, and a light chain CDR3 having the amino acid sequence set forth in SEQ ID NO: 154; (13) a light chain CDR1 having the amino acid sequence set forth in SEQ ID NO: 155, a light chain CDR2 having the amino acid sequence set forth in SEQ ID NO: 156, and a light chain CDR3 having the amino acid sequence set forth in SEQ ID NO: 157; (14) a light chain CDR1 having the amino acid sequence set forth in SEQ ID NO: 158, a light chain CDR2 having the amino acid sequence set forth in SEQ ID NO: 159, and a light chain CDR3 having the amino acid sequence set forth in SEQ ID NO: 160; (15) a light chain CDR1 having the amino acid sequence set forth in SEQ ID NO: 161, a light chain CDR2 having the amino acid sequence set forth in SEQ ID NO: 162, and a light chain CDR3 having the amino acid sequence set forth in SEQ ID NO: 163; (16) a light chain CDR1 having the amino acid sequence set forth in SEQ ID NO: 173, a light chain CDR2 having the amino acid sequence set forth in SEQ ID NO: 174, and a light chain CDR3 having the amino acid sequence set forth in SEQ ID NO: 175; (17) A light chain CDR1 having the amino acid sequence set forth in SEQ ID NO: 176, a light chain CDR2 having the amino acid sequence set forth in SEQ ID NO: 177, and a light chain CDR3 having the amino acid sequence set forth in SEQ ID NO: 178; or (18) A light chain CDR1 having the amino acid sequence set forth in SEQ ID NO: 179, a light chain CDR2 having the amino acid sequence set forth in SEQ ID NO: 180, and a light chain CDR3 having the amino acid sequence set forth in SEQ ID NO:

181. and a light chain variable region comprising: The antibody or antigen-binding fragment thereof according to claim 1 or 2,

6. the heavy chain variable region comprises a heavy chain CDR1 having the amino acid sequence set forth in SEQ ID NO: 104, a heavy chain CDR2 having the amino acid sequence set forth in SEQ ID NO: 105, and a heavy chain CDR3 having the amino acid sequence set forth in SEQ ID NO: 106; the light chain variable region comprises a light chain CDR1 having the amino acid sequence set forth in SEQ ID NO: 149, a light chain CDR2 having the amino acid sequence set forth in SEQ ID NO: 150, and a light chain CDR3 having the amino acid sequence set forth in SEQ ID NO: 151; An antibody or an antigen-binding fragment thereof according to claim 1 or 2.

7. The antibody or antigen-binding fragment thereof according to claim 1 or 2, wherein the heavy chain variable region has framework region 1 having the amino acid sequence set forth in SEQ ID NO: 32, framework region 2 having the amino acid sequence set forth in SEQ ID NO: 40, framework region 3 having the amino acid sequence set forth in SEQ ID NO: 46, and framework region 4 having the amino acid sequence set forth in SEQ ID NO:

54.

8. The antibody or antigen-binding fragment thereof according to claim 1 or 2, wherein the light chain variable region has framework region 1 having the amino acid sequence set forth in SEQ ID NO:57, framework region 2 having the amino acid sequence set forth in SEQ ID NO:72, framework region 3 having the amino acid sequence set forth in SEQ ID NO:79, and framework region 4 having the amino acid sequence set forth in SEQ ID NO:

86.

9. the heavy chain variable region has an amino acid sequence selected from the group consisting of SEQ ID NOs: 1-6, 8, and 9; the light chain variable region has an amino acid sequence selected from the group consisting of SEQ ID NOs: 10, 12-15, 17-21, and 29-31; An antibody or an antigen-binding fragment thereof according to claim 1 or 2.

10. The antibody or antigen-binding fragment thereof according to claim 1 or 2, wherein the heavy chain variable region has the amino acid sequence set forth in SEQ ID NO: 6 and the light chain variable region has the amino acid sequence set forth in SEQ ID NO:

21.

11. A composition for use in targeting HEG1 protein expressed in mesothelioma, comprising the antibody or antigen-binding fragment thereof described in claim 1 or 2.

12. 3. Use of an antibody or antigen-binding fragment thereof according to claim 1 or 2 in the manufacture of a composition for use in targeting HEG1 protein expressed in mesothelioma.