Antibody-drug conjugate containing Anti-CLDN6 antibody

Abstract

Provided in the present disclosure are an antibody-drug conjugate containing an anti-CLDN6 antibody or an antigen-binding portion thereof, a pharmaceutical composition thereof and the use thereof. The antibody-drug conjugate of the present disclosure can be used for treating and / or preventing a variety of cancers or diseases associated with cells expressing CLDN6 in a subject.

Description

Antibody-drug conjugates containing anti-CLDN6 antibody Cross-reference to related applications This application claims priority and benefit from PCT application No. PCT / CN2024 / 131250, filed on November 11, 2024. The entire contents of PCT / CN2024 / 131250 are incorporated herein by reference for all purposes. Technical Field This disclosure generally relates to antibody-drug conjugates, and more specifically, to antibody-drug conjugates comprising anti-CLDN6 antibodies, pharmaceutical compositions thereof, and uses thereof. Background Technology Claudins (CLDNs) are tight junction proteins primarily expressed in tissue-specific ways in endothelial or epithelial cells. As a member of the CLDN family, CLDN6 is highly expressed in fetal tissues such as the stomach, pancreas, lung, and kidney, but not in the corresponding normal adult tissues. The role of CLDN6 in cancer has attracted attention, and strong evidence suggests that altered CLDN6 expression is associated with the development of various cancers. Malignant tumor phenotypes affected by CLDN6 include proliferation and apoptosis, migration and invasion, and drug resistance; these phenotypes are regulated by key signaling pathways mediated by CLDN6. Given its important role in tumors and its low or absent expression in normal tissues, CLDN6 is an ideal target for cancer therapy. Antibody-drug conjugates (ADCs) represent a new class of therapeutic agents that contain antibodies conjugated to cytotoxic drugs via chemical linkers. The therapeutic concept of ADCs is to combine the binding ability of antibodies with that of drugs, where the antibodies are used to deliver drugs to tumor cells by binding to target surface antigens. Summary of the Invention This disclosure provides antibody-drug conjugates comprising an antibody, preferably a chimeric monoclonal antibody or a humanized monoclonal antibody, that binds to human CLDN6, and a drug moiety conjugated via a linker. The antibody-drug conjugates of this disclosure can be used to treat various cancers in subjects. On the one hand, this disclosure provides an antibody-drug conjugate comprising: Anti-CLDN6 antibody or its antigen-binding moiety, and One or more pharmaceutical portions, said pharmaceutical portions being directly or via a linker (preferably covalently linked) to the anti-CLDN6 antibody or its antigen-binding portion, wherein The anti-CLDN6 antibody or its antigen-binding moiety includes a heavy chain variable region and a light chain variable region. The anti-CLDN6 antibody comprises: (1)CDRH1, which contains the sequence X1YNMH or is composed of the sequence, where X1 is selected from D or S; (2) CDRH2, which contains the sequence YX1X2PX3X4X5X6TX7YNQKFKG or is composed of the sequence, where X1 is selected from V or I, X2 is selected from N or Y, X3 is selected from N or G, X4 is selected from N or Q or S or A, X5 is selected from A or G or D or Q or S, X6 is selected from A or G, and X7 is selected from S or N; (3) CDRH3, which contains the sequence WX1X2YVYYYGX3DY or SEQ ID NO: 23 or is composed of it, X1 is selected from D or E or S or G, X2 is selected from A or G or S or D or Q, and X3 is selected from L or M; (4) CDRL1, which contains or consists of the sequence SEQ ID NO: 27 or SEQ ID NO: 29; (5) CDRL2, which contains or consists of the sequence SEQ ID NO: 30 or SEQ ID NO: 31; and (6) CDRL3, which contains or consists of the sequence QQYWX1TPYT or SEQ ID NO: 40, where X1 is selected from S or N; Or the anti-CLDN6 antibody may contain: (1) CDRH1, which contains or consists of SEQ ID NO: 5; (2) CDRH2, which contains or consists of SEQ ID NO: 12, or contains or consists of the sequence YX1NPNNGAX2X3YNQKFKG, where X1 is selected from A, I, L or V, X2 is selected from S or T, and X3 is selected from S or N; preferably, CDRH2 contains or consists of the sequence SEQ ID NO: 12, 91, 92, 93, 94, 119, 120, 121, 122, 123, 124 or 125; (3) CDRH3, which contains or consists of SEQ ID NO: 20, or contains the sequence WDGYX1YYYGX2DX3 or consists of the sequence, wherein X1 is selected from V or S, X2 is selected from V, L or M, and X3 is selected from Y or F; preferably, CDRH3 contains or consists of the sequence SEQ ID NO: 20, 95, 96, 97, 126, 127, 128, 129, 130, or 131; (4) CDRL1, which contains or is composed of the sequence SEQ ID NO: 27, or contains or is composed of the sequence KASX1HX2NX3WLA, wherein X1 is selected from E or D, X2 is selected from I or V, and X3 is selected from H or Q; preferably, CDRL1 contains or is composed of SEQ ID NO: 27, 98, 99, 100, 132, 133, 134, or 135; (5) CDRL2, which contains or consists of SEQ ID NO: 31, or which contains or consists of SEQ ID NO: 101; and (6) CDRL3, which comprises or is composed of SEQ ID NO: 37, or comprises or is composed of QQYX1X2TPYX3, wherein X1 is selected from W or G, X2 is selected from S, H or N, and X3 is selected from S or T; preferably, CDRL3 comprises or is composed of SEQ ID NO: 37, 102, 103, 104, 136, 137, 138, 139, 140, 141 or 142; Or the anti-CLDN6 antibody may contain: (1) CDRH1, which contains the sequence SYX1IX2 or is composed of the sequence, wherein X1 is selected from N or G and X2 is selected from H or S; (2) CDRH2, which contains or consists of the sequence X1IYPX2X3GX4TX5X6NEX7FKG, wherein X1 is selected from Y or E, X2 is selected from G or R, X3 is selected from N or S, X4 is selected from G or N, X5 is selected from K or Y, X6 is selected from Y or H, and X7 is selected from R or K. (3) CDRH3, which contains the sequence SEQ ID NO: 16 or SEQ ID NO: 19; (4) CDRL1, which contains the sequence SEQ ID NO: 24 or SEQ ID NO: 26, or is composed of SEQ ID NO: 24 or SEQ ID NO: 26; (5) CDRL2, which contains the sequence X1X2SNLX3S or is composed of the sequence, wherein X1 is selected from L or G, X2 is selected from A or T, and X3 is selected from E or A; and (6) CDRL3, which contains the sequence SEQ ID NO: 34 or SEQ ID NO: 179, or is composed of SEQ ID NO: 34 or SEQ ID NO: 179; Or the anti-CLDN6 antibody may contain: (1) CDRH1, which contains or consists of the sequence X1YX2MS, wherein X1 is selected from S or N and X2 is selected from G or A; (2) CDRH2, which contains the sequence TISX1GGSYTX2YPDX3X4KG or is composed of the sequence, wherein X1 is selected from S or D, X2 is selected from Y or S, X3 is selected from S or N, and X4 is selected from V or I; (3) CDRH3, which contains the sequence SEQ ID NO: 17 or SEQ ID NO: 18, or is composed of SEQ ID NO: 17 or SEQ ID NO: 18; (4) CDRL1, which contains the sequence SEQ ID NO: 25 or consists of SEQ ID NO: 25; (5) CDRL2, which contains the sequence X1X2TSLET or is composed of the sequence, wherein X1 is selected from G or A, and X2 is selected from A or T; and (6) CDRL3, which contains the sequence QQYWSX1PX2T or is composed of the sequence, wherein X1 is selected from T or F, and X2 is selected from P or R; and wherein The drug is selected from one or more of the following: cytotoxic agents, cell inhibitors, chemotherapeutic agents, radiotherapy agents, anti-angiogenic agents, immunosuppressants, anti-metastatic agents, targeted anticancer agents, and other anticancer agents. On the one hand, this disclosure provides an antibody-drug conjugate comprising: Anti-CLDN6 antibody or its antigen-binding moiety, and One or more pharmaceutical portions, said pharmaceutical portions being directly or via a linker (preferably covalently linked) to the anti-CLDN6 antibody or its antigen-binding portion, wherein The anti-CLDN6 antibody or its antigen-binding moiety includes a heavy chain variable region and a light chain variable region. The anti-CLDN6 antibody comprises: (1)CDRH1, which contains the sequence X1YNMH or is composed of the sequence, where X1 is selected from D or S; (2) CDRH2, which contains the sequence YX1X2PX3X4X5X6TX7YNQKFKG or is composed of the sequence, where X1 is selected from V or I, X2 is selected from N or Y, X3 is selected from N or G, X4 is selected from N or Q or S or A, X5 is selected from A or G or D or Q or S, X6 is selected from A or G, and X7 is selected from S or N; (3) CDRH3, which contains the sequence WX1X2YVYYYGX3DY or SEQ ID NO: 23 or is composed of it, X1 is selected from D or E or S or G, X2 is selected from A or G or S or D or Q, and X3 is selected from L or M; (4) CDRL1, which contains or consists of the sequence SEQ ID NO: 27 or SEQ ID NO: 29; (5) CDRL2, which contains or consists of the sequence SEQ ID NO: 30 or SEQ ID NO: 31; and (6) CDRL3, which contains or consists of the sequence QQYWX1TPYT or SEQ ID NO: 40, where X1 is selected from S or N; Preferably, the anti-CLDN6 antibody comprises: (1) CDRH1, which contains the sequence SEQ ID NO: 5 or consists of SEQ ID NO: 5; (2) CDRH2, which contains the sequence YX1NPNX2X3ATX4YNQKFKG or is composed of the sequence, wherein X1 is selected from V or I, X2 is selected from N or Q or S or A, X3 is selected from A or G or D or Q or S, and X4 is selected from S or N; (3) CDRH3, which contains the sequence WDGYVYYYGX1DY or is composed of the sequence, wherein X1 is selected from L or M; (4) CDRL1, which contains the sequence SEQ ID NO: 27 or consists of SEQ ID NO: 27; (5) CDRL2, which comprises the sequence SEQ ID NO: 31 or SEQ ID NO: 31; and (6) CDRL3, which contains the sequence QQYWX1TPYT or is composed of the sequence, wherein X1 is selected from S or N; More preferably, the anti-CLDN6 antibody comprises: (1) CDRH1, which contains the sequence SEQ ID NO: 5 or consists of SEQ ID NO: 5; (2) CDRH2, which contains the sequence YX1NPNNGATX2YNQKFKG or is composed of the sequence, wherein X1 is selected from V or I, and X2 is selected from S or N; (3) CDRH3, which contains the sequence WDGYVYYYGX1DY or is composed of the sequence, wherein X1 is selected from L or M; (4) CDRL1, which contains the sequence SEQ ID NO: 27 or consists of SEQ ID NO: 27; (5) CDRL2, which contains the sequence SEQ ID NO: 31 or consists of SEQ ID NO: 31; and (6) CDRL3, which contains the sequence QQYWX1TPYT or is composed of the sequence, wherein X1 is selected from S or N; Or the anti-CLDN6 antibody may contain: (1) CDRH1, which contains the sequence SYX1IX2 or is composed of the sequence, wherein X1 is selected from N or G and X2 is selected from H or S; (2) CDRH2, which contains or consists of the sequence X1IYPX2X3GX4TX5X6NEX7FKG, wherein X1 is selected from Y or E, X2 is selected from G or R, X3 is selected from N or S, X4 is selected from G or N, X5 is selected from K or Y, X6 is selected from Y or H, and X7 is selected from R or K. (3) CDRH3, which contains the sequence SEQ ID NO: 16 or SEQ ID NO: 19; (4) CDRL1, which contains the sequence SEQ ID NO: 24 or SEQ ID NO: 26, or is composed of SEQ ID NO: 24 or SEQ ID NO: 26; (5) CDRL2, which contains the sequence X1X2SNLX3S or is composed of the sequence, wherein X1 is selected from L or G, X2 is selected from A or T, and X3 is selected from E or A; and (6) CDRL3, which contains the sequence SEQ ID NO: 34 or SEQ ID NO: 179, or is composed of SEQ ID NO: 34 or SEQ ID NO: 179; Or the anti-CLDN6 antibody may contain: (1) CDRH1, which contains or consists of the sequence X1YX2MS, wherein X1 is selected from S or N and X2 is selected from G or A; (2) CDRH2, which contains the sequence TISX1GGSYTX2YPDX3X4KG or is composed of the sequence, wherein X1 is selected from S or D, X2 is selected from Y or S, X3 is selected from S or N, and X4 is selected from V or I; (3) CDRH3, which contains the sequence SEQ ID NO: 17 or SEQ ID NO: 18, or is composed of SEQ ID NO: 17 or SEQ ID NO: 18; (4) CDRL1, which contains the sequence SEQ ID NO: 25 or consists of SEQ ID NO: 25; (5) CDRL2, which contains the sequence X1X2TSLET or is composed of the sequence, wherein X1 is selected from G or A, and X2 is selected from A or T; and (6) CDRL3, which contains the sequence QQYWSX1PX2T or is composed of the sequence, wherein X1 is selected from T or F, and X2 is selected from P or R; and wherein The drug is selected from one or more of the following: cytotoxic agents, cell inhibitors, chemotherapeutic agents, radiotherapy agents, anti-angiogenic agents, immunosuppressants, anti-metastatic agents, targeted anticancer agents, and other anticancer agents. On the one hand, this disclosure provides an antibody-drug conjugate comprising: Anti-CLDN6 antibody or its antigen-binding moiety, and One or more pharmaceutical portions, said pharmaceutical portions being directly or via a linker (preferably covalently linked) to the anti-CLDN6 antibody or its antigen-binding portion, wherein The anti-CLDN6 antibody or its antigen-binding moiety includes a heavy chain variable region and a light chain variable region. The heavy chain variable region includes: (i) CDRH1, which comprises any sequence shown in SEQ ID NO: 1-5 and 7 or any sequence having at least 80%, 82%, 85%, 88%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% sequence identity with SEQ ID NO: 1-5 and 7; (ii) CDRH2, comprising any sequence shown in SEQ ID NO: 8-13, 15, and 74-76 or any sequence having at least 80%, 82%, 85%, 88%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% sequence identity with SEQ ID NO: 8-13, 15, and 74-76; and (iii) CDRH3, comprising any sequence shown in SEQ ID NO: 16-21, 23 and 77-78 or any sequence having at least 80%, 82%, 85%, 88%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% sequence identity with SEQ ID NO: 16-21, 23 and 77-78; The light chain variable region includes: (i) CDRL1, which comprises any sequence shown in SEQ ID NO: 24-27 and 29 or any sequence having at least 80%, 82%, 85%, 88%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% sequence identity with SEQ ID NO: 24-27 and 29; (ii) CDRL2, comprising any sequence shown in SEQ ID NO: 30-33 or any sequence having at least 80%, 82%, 85%, 88%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% sequence identity with SEQ ID NO: 30-33; and (iii) CDRL3, comprising any sequence shown in SEQ ID NO: 34-38, 40 and 179 or any sequence having at least 80%, 82%, 85%, 88%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% sequence identity with SEQ ID NO: 34-38, 40 and 179; and wherein The drug is selected from one or more of the following: cytotoxic agents, cell inhibitors, chemotherapeutic agents, radiotherapy agents, anti-angiogenic agents, immunosuppressants, anti-metastatic agents, targeted anticancer agents, and other anticancer agents. In some embodiments, this disclosure provides an antibody-drug conjugate, wherein the anti-CLDN6 antibody or its antigen-binding portion comprises: (a) CDRH1 comprising or consisting of any of SEQ ID NO: 1-5 and 7; (b) CDRH2 comprising or consisting of any of SEQ ID NO: 8-13, 15, 74-76; (c) CDRH3 comprising or consisting of any of SEQ ID NO: 16-21, 23, 77-78; (d) CDRL1 comprising or consisting of any of SEQ ID NO: 24-27 and 29; (e) CDRL2 comprising or consisting of any of SEQ ID NO: 30-33; and (f) CDRL3 comprising or consisting of any of SEQ ID NO: 34-38, 40 and 179. In some embodiments, this disclosure provides an antibody-drug conjugate, wherein the anti-CLDN6 antibody or its antigen-binding portion comprises: (a) CDRH1 comprising or consisting of SEQ ID NO: 1; CDRH2 comprising or consisting of SEQ ID NO: 8; CDRH3 comprising or consisting of SEQ ID NO: 16; CDRL1 comprising or consisting of SEQ ID NO: 24; CDRL2 comprising or consisting of SEQ ID NO: 30; and CDRL3 comprising or consisting of SEQ ID NO: 34; (b) CDRH1 comprising or consisting of SEQ ID NO: 2; CDRH2 comprising or consisting of SEQ ID NO: 9; CDRH3 comprising or consisting of SEQ ID NO: 17; CDRL1 comprising or consisting of SEQ ID NO: 25; CDRL2 comprising or consisting of SEQ ID NO: 31; and CDRL3 comprising or consisting of SEQ ID NO: 35; (c) CDRH1 comprising or consisting of SEQ ID NO: 3; CDRH2 comprising or consisting of SEQ ID NO: 10; CDRH3 comprising or consisting of SEQ ID NO: 18; CDRL1 comprising or consisting of SEQ ID NO: 25; CDRL2 comprising or consisting of SEQ ID NO: 32; and CDRL3 comprising or consisting of SEQ ID NO: 36; (d) CDRH1 comprising or consisting of SEQ ID NO: 4; CDRH2 comprising or consisting of SEQ ID NO: 11; CDRH3 comprising or consisting of SEQ ID NO: 19; CDRL1 comprising or consisting of SEQ ID NO: 26; CDRL2 comprising or consisting of SEQ ID NO: 33; and CDRL3 comprising or consisting of SEQ ID NO: 179; (e) CDRH1 comprising or consisting of SEQ ID NO: 5; CDRH2 comprising or consisting of SEQ ID NO: 12; CDRH3 comprising or consisting of SEQ ID NO: 20; CDRL1 comprising or consisting of SEQ ID NO: 27; CDRL2 comprising or consisting of SEQ ID NO: 31; and CDRL3 comprising or consisting of SEQ ID NO: 37; (f) CDRH1 comprising or consisting of SEQ ID NO: 5; CDRH2 comprising or consisting of SEQ ID NO: 13; CDRH3 comprising or consisting of SEQ ID NO: 21; CDRL1 comprising or consisting of SEQ ID NO: 27; CDRL2 comprising or consisting of SEQ ID NO: 31; and CDRL3 comprising or consisting of SEQ ID NO: 38; or (g) CDRH1 comprising or consisting of SEQ ID NO: 7; CDRH2 comprising or consisting of SEQ ID NO: 15; CDRH3 comprising or consisting of SEQ ID NO: 23; CDRL1 comprising or consisting of SEQ ID NO: 29; CDRL2 comprising or consisting of SEQ ID NO: 30; and CDRL3 comprising or consisting of SEQ ID NO: 40; or (h) comprising CDRH1 shown or composed of SEQ ID NO: 5; CDRH2 shown or composed of SEQ ID NO: 12; CDRH3 shown or composed of SEQ ID NO: 20; CDRL1 shown or composed of SEQ ID NO: 27; CDRL2 shown or composed of SEQ ID NO: 31; and CDRL3 shown or composed of SEQ ID NO: 38; or (i) CDRH1 comprising or consisting of SEQ ID NO: 7; CDRH2 comprising or consisting of SEQ ID NO: 74; CDRH3 comprising or consisting of SEQ ID NO: 23; CDRL1 comprising or consisting of SEQ ID NO: 29; CDRL2 comprising or consisting of SEQ ID NO: 30; and CDRL3 comprising or consisting of SEQ ID NO: 40; or (j) CDRH1 comprising or consisting of SEQ ID NO: 5; CDRH2 comprising or consisting of SEQ ID NO: 75; CDRH3 comprising or consisting of SEQ ID NO: 20; CDRL1 comprising or consisting of SEQ ID NO: 27; CDRL2 comprising or consisting of SEQ ID NO: 31; and CDRL3 comprising or consisting of SEQ ID NO: 37; or (k) comprising CDRH1 as shown or composed of SEQ ID NO: 5; CDRH2 as shown or composed of SEQ ID NO: 76; CDRH3 as shown or composed of SEQ ID NO: 20; CDRL1 as shown or composed of SEQ ID NO: 27; CDRL2 as shown or composed of SEQ ID NO: 31; and CDRL3 as shown or composed of SEQ ID NO: 37; or (l) CDRH1 comprising or consisting of SEQ ID NO: 5; CDRH2 comprising or consisting of SEQ ID NO: 12; CDRH3 comprising or consisting of SEQ ID NO: 77; CDRL1 comprising or consisting of SEQ ID NO: 27; CDRL2 comprising or consisting of SEQ ID NO: 31; and CDRL3 comprising or consisting of SEQ ID NO: 37; or (m) includes CDRH1 shown or composed of SEQ ID NO: 5; CDRH2 shown or composed of SEQ ID NO: 12; CDRH3 shown or composed of SEQ ID NO: 78; CDRL1 shown or composed of SEQ ID NO: 27; CDRL2 shown or composed of SEQ ID NO: 31; and CDRL3 shown or composed of SEQ ID NO: 37. In some embodiments, in the antibody-drug conjugates provided in this disclosure, the heavy chain variable region comprises any amino acid sequence of SEQ ID NO: 41-46, 48-60, 79-83 or a sequence thereof, or any amino acid sequence of SEQ ID NO: 41-46, 48-60, 79-83 having at least 80%, for example at least 82%, 85%, 88%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% sequence identity with the sequence of SEQ ID NO: 41-46, 48-60, 79-83; the light chain variable region comprises any amino acid sequence of SEQ ID NO: 61-66, 68-73 or a sequence thereof, or a sequence of SEQ ID NO: 61-66, 68-73 having at least 80%, for example at least 82%, 85%, 88%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% sequence identity with the sequence of SEQ ID NO: 41-46, 48-60, 79-83. The sequences NO: 61-66, 68-73 have at least 80%, for example at least 82%, 85%, 88%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% sequence identity of any amino acid sequence or a sequence composed thereof. In some embodiments, this disclosure provides an antibody-drug conjugate, wherein the anti-CLDN6 antibody or its antigen-binding portion comprises: (a) A heavy chain variable region comprising an amino acid sequence or being composed thereof that is at least 80% identical to the sequence of SEQ ID NO: 41, and a light chain variable region comprising an amino acid sequence or being composed thereof that is at least 80% identical to the sequence of SEQ ID NO: 61; or (b) a heavy chain variable region comprising or consisting of an amino acid sequence identical to at least 80% of the sequence of SEQ ID NO: 42 and a light chain variable region comprising or consisting of an amino acid sequence identical to at least 80% of the sequence of SEQ ID NO: 62; or (c) A heavy chain variable region comprising or consisting of an amino acid sequence identical to at least 80% of the sequence of SEQ ID NO: 43 and a light chain variable region comprising or consisting of an amino acid sequence identical to at least 80% of the sequence of SEQ ID NO: 63; or (d) A heavy chain variable region comprising or consisting of an amino acid sequence identical to at least 80% of the sequence of SEQ ID NO: 44, and a light chain variable region comprising or consisting of an amino acid sequence identical to at least 80% of the sequence of SEQ ID NO: 64; or (e) a heavy chain variable region comprising an amino acid sequence or being composed of an amino acid sequence identical to at least 80% of any of the sequences in SEQ ID NO: 45 or 80-83, and a light chain variable region comprising an amino acid sequence or being composed of an amino acid sequence identical to at least 80% of the sequence in SEQ ID NO: 65; or (f) a heavy chain variable region comprising or consisting of an amino acid sequence identical to at least 80% of the sequence of SEQ ID NO: 46 or 45, and a light chain variable region comprising or consisting of an amino acid sequence identical to at least 80% of the sequence of SEQ ID NO: 66; or (g) a heavy chain variable region comprising or consisting of an amino acid sequence identical to at least 80% of the sequence of SEQ ID NO: 48 or 79, and a light chain variable region comprising or consisting of an amino acid sequence identical to at least 80% of the sequence of SEQ ID NO: 68; or (h) a heavy chain variable region comprising an amino acid sequence or being composed of an amino acid sequence that is at least 80% identical to any of the sequences in SEQ ID NO: 49-52, and a light chain variable region comprising an amino acid sequence or being composed of an amino acid sequence that is at least 80% identical to any of the sequences in SEQ ID NO: 69; or (i) a heavy chain variable region comprising an amino acid sequence identical to at least 80% of any of the sequences in SEQ ID NO: 49-52 and a light chain variable region comprising an amino acid sequence identical to at least 80% of the sequence in SEQ ID NO: 70; or (j) a heavy chain variable region comprising an amino acid sequence identical to or consisting of at least 80% of the sequence of SEQ ID NO: 53 or 54, and a light chain variable region comprising an amino acid sequence identical to or consisting of at least 80% of the sequence of SEQ ID NO: 71; or (k) a heavy chain variable region comprising an amino acid sequence or being composed of any of the sequences in SEQ ID NO: 53-56 that is at least 80% sequence identical, and a light chain variable region comprising an amino acid sequence or being composed of an amino acid sequence that is at least 80% sequence identical, to any of the sequences in SEQ ID NO: 72; or (l) A heavy chain variable region comprising an amino acid sequence or being composed of any of the sequences in SEQ ID NO: 57-60 that is at least 80% sequence identical, and a light chain variable region comprising an amino acid sequence or being composed of any of the sequences in SEQ ID NO: 73 that is at least 80% sequence identical. In some embodiments, this disclosure provides an antibody-drug conjugate, wherein the anti-CLDN6 antibody or its antigen-binding portion comprises: (a) A heavy chain variable region comprising or consisting of the amino acid sequence of SEQ ID NO: 41 and a light chain variable region comprising or consisting of the amino acid sequence of SEQ ID NO: 61; or (b) a heavy chain variable region comprising or consisting of the amino acid sequence of SEQ ID NO: 42 and a light chain variable region comprising or consisting of the amino acid sequence of SEQ ID NO: 62; or (c) A heavy chain variable region comprising or consisting of the amino acid sequence of SEQ ID NO: 43 and a light chain variable region comprising or consisting of the amino acid sequence of SEQ ID NO: 63; or (d) A heavy chain variable region comprising or consisting of the amino acid sequence of SEQ ID NO: 44 and a light chain variable region comprising or consisting of the amino acid sequence of SEQ ID NO: 64; or (e) a heavy chain variable region comprising or consisting of any of the amino acid sequences in SEQ ID NO: 45 or 80-83, and a light chain variable region comprising or consisting of the amino acid sequence in SEQ ID NO: 65; or (f) A heavy chain variable region comprising or consisting of the amino acid sequence of SEQ ID NO: 46 or 45 and a light chain variable region comprising or consisting of the amino acid sequence of SEQ ID NO: 66; or (g) A heavy chain variable region comprising or consisting of the amino acid sequence of SEQ ID NO: 48 or 79 and a light chain variable region comprising or consisting of the amino acid sequence of SEQ ID NO: 68; or (h) a heavy chain variable region comprising or consisting of any of the amino acid sequences in SEQ ID NO: 49-52 and a light chain variable region comprising or consisting of the amino acid sequence in SEQ ID NO: 69; or (i) a heavy chain variable region comprising or consisting of any of the amino acid sequences in SEQ ID NO: 49-52 and a light chain variable region comprising or consisting of the amino acid sequence in SEQ ID NO: 70; or (j) A heavy chain variable region comprising or consisting of the amino acid sequence of SEQ ID NO: 53 or 54 and a light chain variable region comprising or consisting of the amino acid sequence of SEQ ID NO: 71; or (k) a heavy chain variable region comprising or consisting of any of the amino acid sequences in SEQ ID NO: 53-56 and a light chain variable region comprising or consisting of the amino acid sequence in SEQ ID NO: 72; or (l) a heavy chain variable region comprising or consisting of any of the amino acid sequences in SEQ ID NO: 57-60 and a light chain variable region comprising or consisting of the amino acid sequence in SEQ ID NO: 73. On the one hand, this disclosure provides an antibody-drug conjugate comprising: Anti-CLDN6 antibody or its antigen-binding moiety, and One or more pharmaceutical portions, said pharmaceutical portions being directly or via a linker (preferably covalently linked) to the anti-CLDN6 antibody or its antigen-binding portion, wherein The anti-CLDN6 antibody or its antigen-binding portion comprises a complementarity-determining region sequence selected from the sequences shown in SEQ ID NO: 41-46, 48-60, 79-83 and a complementarity-determining region sequence selected from the sequences shown in SEQ ID NO: 61-66, 68-73; and wherein The drug is selected from one or more of the following: cytotoxic agents, cell inhibitors, chemotherapeutic agents, radiotherapy agents, anti-angiogenic agents, immunosuppressants, anti-metastatic agents, targeted anticancer agents, and other anticancer agents. On the one hand, this disclosure provides an antibody-drug conjugate comprising: Anti-CLDN6 antibody or its antigen-binding moiety, and One or more pharmaceutical portions, said pharmaceutical portions being directly or via a linker (preferably covalently linked) to the anti-CLDN6 antibody or its antigen-binding portion, wherein The anti-CLDN6 antibody or its antigen-binding moiety includes a heavy chain variable region and a light chain variable region. The anti-CLDN6 antibody comprises: (1) CDRH1, which contains or consists of SEQ ID NO: 5; (2) CDRH2, which contains or consists of SEQ ID NO: 12, or contains or consists of the sequence YX1NPNNGAX2X3YNQKFKG, where X1 is selected from A, I, L or V, X2 is selected from S or T, and X3 is selected from S or N; preferably, CDRH2 contains or consists of the sequence SEQ ID NO: 12, 91, 92, 93, 94, 119, 120, 121, 122, 123, 124 or 125; (3) CDRH3, which contains or consists of SEQ ID NO: 20, or contains the sequence WDGYXiYYYGX2DX3 or consists of the sequence, wherein X1 is selected from V or S, X2 is selected from V, L or M, and X3 is selected from Y or F; preferably, CDRH3 contains or consists of the sequence SEQ ID NO: 20, 95, 96, 97, 126, 127, 128, 129, 130, or 131; (4) CDRL1, which contains or consists of SEQ ID NO: 27, or contains the sequence KASX1HX2NX3WLA or consists of the sequence, wherein X1 is selected from E or D, X2 is selected from I or V, and X3 is selected from H or Q; preferably, CDRL1 contains or consists of SEQ ID NO: 27, 98, 99, 100, 132, 133, 134, or 135; (5) CDRL2, which contains or consists of SEQ ID NO: 31, or which contains or consists of SEQ ID NO: 101; and (6) CDRL3, which comprises or is composed of SEQ ID NO: 37, or comprises or is composed of QQYX1X2TPYX3, wherein X1 is selected from W or G, X2 is selected from S, H or N, and X3 is selected from S or T; preferably, CDRL3 comprises or is composed of SEQ ID NO: 37, 102, 103, 104, 136, 137, 138, 139, 140, 141 or 142; Preferably, the anti-CLDN6 antibody comprises: (1) CDRH1, which contains or consists of SEQ ID NO: 5; (2) CDRH2, which contains or consists of SEQ ID NO: 12, or contains or consists of the sequence YX1NPNNGAX2X3YNQKFKG, where X1 is selected from A, I, L or V, X2 is selected from S or T, and X3 is selected from S or N; preferably, CDRH2 contains or consists of the sequence SEQ ID NO: 12, 91, 92, 93, 94, 119, 120, 121, 122, 123, 124 or 125; (3) CDRH3, which contains or consists of SEQ ID NO: 20; (4) CDRL1, which contains or consists of SEQ ID NO: 27; (5) CDRL2, which contains or consists of SEQ ID NO: 31; and (6) CDRL3, which contains or consists of SEQ ID NO: 37; Alternatively, the anti-CLDN6 antibody comprises: (1) CDRH1, which contains or consists of SEQ ID NO: 5; (2) CDRH2, which contains or consists of SEQ ID NO: 12; (3) CDRH3, which contains or consists of SEQ ID NO: 20, or contains the sequence WDGYX1YYYGX2DX3 or consists of the sequence, wherein X1 is selected from V or S, X2 is selected from V, L or M, and X3 is selected from Y or F; preferably, CDRH3 contains or consists of the sequence SEQ ID NO: 20, 95, 96, 97, 126, 127, 128, 129, 130, or 131; (4) CDRL1, which contains or consists of SEQ ID NO: 27; (5) CDRL2, which contains or consists of sEQ ID NO: 31; and (6) CDRL3, which contains or consists of SEQ ID NO: 37; Alternatively, the anti-CLDN6 antibody comprises: (1) CDRH1, which contains or consists of SEQ ID NO: 5; (2) CDRH2, which contains or consists of SEQ ID NO: 12; (3) CDRH3, which contains or consists of SEQ ID NO: 20; (4) CDRL1, which contains or consists of SEQ ID NO: 27, or contains the sequence KASX1HX2NX3WLA or consists of the sequence, wherein X1 is selected from E or D, X2 is selected from I or V, and X3 is selected from H or Q; preferably, CDRL1 contains or consists of SEQ ID NO: 27, 98, 99, 100, 132, 133, 134, or 135; (5) CDRL2, which contains or consists of SEQ ID NO: 31; and (6) CDRL3, which contains or consists of SEQ ID NO: 37; Alternatively, the anti-CLDN6 antibody comprises: (1) CDRH1, which contains or consists of SEQ ID NO: 5; (2) CDRH2, which contains or consists of SEQ ID NO: 12; (3) CDRH3, which contains or consists of SEQ ID NO: 20; (4) CDRL1, which contains or consists of SEQ ID NO: 27; (5) CDRL2, which contains or consists of SEQ ID NO: 31, or which contains or consists of SEQ ID NO: 101; and (6) CDRL3, which contains or consists of SEQ ID NO: 37; Alternatively, the anti-CLDN6 antibody comprises: (1) CDRH1, which contains or consists of SEQ ID NO: 5; (2) CDRH2, which contains or consists of SEQ ID NO: 12; (3) CDRH3, which contains or consists of SEQ ID NO: 20; (4) CDRL1, which contains or consists of SEQ ID NO: 27; (5) CDRL2, which contains or consists of SEQ ID NO: 31; and (6) CDRL3, which comprises or is composed of SEQ ID NO: 37, or comprises or is composed of QQYX1X2TPYX3, wherein X1 is selected from W or G, X2 is selected from S, H or N, and X3 is selected from S or T; preferably, CDRL3 comprises or is composed of SEQ ID NO: 37, 102, 103, 104, 136, 137, 138, 139, 140, 141 or 142; Alternatively, the anti-CLDN6 antibody comprises: (1) CDRH1, which contains or consists of SEQ ID NO: 5; (2) CDRH2, which includes or consists of any one of SEQ ID NO: 12, 91-94, 119-125; (3) CDRH3, which includes or consists of any one of SEQ ID NO: 20, 95-97, 126-131; (4) CDRL1, which includes or consists of any one of SEQ ID NO: 27, 98-99, 132-135; (5) CDRL2, which contains or consists of SEQ ID NO: 31 or 101; (6) CDRL3, which includes or consists of any one of SEQ ID NO: 37, 102-104, 136-142; Preferably, the anti-CLDN6 antibody comprises or is composed of CDRs as shown in Table L, and wherein The drug is selected from one or more of the following: cytotoxic agents, cell inhibitors, chemotherapeutic agents, radiotherapy agents, anti-angiogenic agents, immunosuppressants, anti-metastatic agents, targeted anticancer agents, and other anticancer agents. On the one hand, this disclosure provides an antibody-drug conjugate comprising: Anti-CLDN6 antibody or its antigen-binding moiety, and One or more pharmaceutical portions, said pharmaceutical portions being directly or via a linker (preferably covalently linked) to the anti-CLDN6 antibody or its antigen-binding portion, wherein The anti-CLDN6 antibody or its antigen-binding moiety includes a heavy chain variable region and a light chain variable region. The heavy chain variable region comprises any amino acid sequence of SEQ ID NO: 105-111 or a sequence thereof, or any amino acid sequence of SEQ ID NO: 105-111 having at least 80%, for example, at least 82%, 85%, 88%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% sequence identity with the sequence of SEQ ID NO: 105-111; the light chain variable region comprises any amino acid sequence of SEQ ID NO: 69 or a sequence thereof, or any amino acid sequence of SEQ ID NO: 69 having at least 80%, for example, at least 82%, 85%, 88%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% sequence identity with the sequence of SEQ ID NO: 69; or The heavy chain variable region comprises a sequence of SEQ ID NO: 52 or thereof, or any amino acid sequence or a sequence comprising thereof having at least 80%, for example, at least 82%, 85%, 88%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% sequence identity with the sequence of SEQ ID NO: 52; the light chain variable region comprises any amino acid sequence of SEQ ID NO: 112-118 or a sequence comprising thereof, or any amino acid sequence or a sequence comprising thereof having at least 80%, for example, at least 82%, 85%, 88%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% sequence identity with the sequence of SEQ ID NO: 112-118, and wherein... The drug is selected from one or more of the following: cytotoxic agents, cell inhibitors, chemotherapeutic agents, radiotherapy agents, anti-angiogenic agents, immunosuppressants, anti-metastatic agents, targeted anticancer agents, and other anticancer agents. In some implementations, the anti-CLDN6 antibody is a monoclonal antibody. In some implementations, the anti-CLDN6 antibody is a chimeric antibody or a humanized antibody. In some embodiments, the anti-CLDN6 antibody comprises a constant region of IgG, preferably selected from the constant regions of IgG1, IgG2, IgG3, or IgG4, and more preferably from the constant region of IgG1. In some embodiments, this disclosure provides an antibody-drug conjugate, wherein the anti-CLDN6 antibody or its antigen-binding portion comprises or consists of a heavy chain composed of any sequence selected from the group consisting of: a polypeptide having at least 80%, 82%, 85%, 88%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% sequence identity with SEQ ID NO: 143-167, SEQ ID NO: 87, or SEQ ID NO: 89; and a light chain comprising or consists of any sequence selected from the group consisting of: a polypeptide having at least 80%, 82%, 85%, 88%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% sequence identity with SEQ ID NO: 168-178, SEQ ID NO: 88, or SEQ ID NO: 90. In some embodiments, this disclosure provides an antibody-drug conjugate, wherein the drug portion is permeable to cell membranes. In some embodiments, this disclosure provides an antibody-drug conjugate, wherein the drug portion is selected from microtubule inhibitors, DNA double-strand disruptors, topoisomerase inhibitors, DNA alkylating agents, RNA polymerase inhibitors, RNA cleavage enzyme inhibitors, Bcl-xL inhibitors, antimitotic agents, sodium-potassium ion pump ATPase inhibitors, matrix metalloproteinase inhibitors, and immune agonists. In some embodiments, this disclosure provides an antibody-drug conjugate, wherein the drug portion is selected from olistatin derivatives, maytansine derivatives, pyrrolobenzodiazepines, etc. Dimer derivatives (such as PBD1), camptothecin derivatives, or cazithromycin derivatives. In some embodiments, this disclosure provides an antibody-drug conjugate wherein the drug portion is selected from salicylate, monomethylolpropionate E (MMAE), monomethylolpropionate A (MMAF), PF-06380101, DXd, topotecan, irinotecan, 9-aminocamptothecin, 7-ethyl-10-hydroxycamptothecin (SN38) and its derivatives, maytansine DM1, maytansine DM4, PDB dimer or N-acetyl-γ11 kazimidycin. In some embodiments, this disclosure provides an antibody-drug conjugate, wherein the adapter is a cleavable adapter. In some embodiments, this disclosure provides an antibody-drug conjugate, wherein the linker comprises an enzyme-cleavable peptide chain portion, for example, cleavable by cathepsins. In some embodiments, this disclosure provides an antibody-drug conjugate, wherein the linker comprises a peptide chain selected from valine-citrulline (VC), valine-alanine (VA), phenylalanine-lysine (FK), and glycine-glycine-phenylalanine-glycine (GGFG). In some embodiments, this disclosure provides an antibody-drug conjugate wherein the linker comprises CL2A or CL2E. In some embodiments, this disclosure provides an antibody-drug conjugate wherein the linker is selected from maleimide-hexanoyl-valine-citrulline-p-aminobenzyloxycarbonyl (MC-VC-PAB), maleimide-hexanoyl-valine-alanine (MC-VA), maleimide-butyric acid-valine-citrulline (MB-VC), maleimide-hexanoyl-glycine-glycine-phenylalanine-glycine (MC-GGFG), valine-citrulline-p-aminobenzyloxycarbonyl (VC-PAB), GGFG, CL2A, or CL2E. In some embodiments, this disclosure provides an antibody-drug conjugate, wherein the anti-CLDN6 antibody is selected from PiH1001, PiH1002, PiH1003, PiH1004, PiH1005, PiH1006, PiH1007, PiH1008, PiH2001, PiH2004, PiH2005, PiH2006, PiH2007, PiH2008, PiH2009, PiH2010, PiH2011, PiH2012, PiH2012-1; and the anti-CLDN6 antibody is conjugated with VC-PAB-MMAE, GGFG-MMAE, VC-PAB-MMAF, GGFG-MMAF, VC-PAB-DXd, GGFG-DXd or VC-PAB-DM1, GGFG-DM1, CL2A-SN38. In some embodiments, this disclosure provides an antibody-drug conjugate, wherein the anti-CLDN6 antibody is selected from PiH1001-M1, PiH1001-M2, PiH1001-M3, PiH1001-M4, PiH1002-M1, PiH1002-M2, PiH1002-M3, PiH1002-M4, PiH1003-M1, PiH1003-M2, PiH1003-M3, PiH1003-M4, PiH1004-M1, PiH1004-M2, PiH1004-M3, PiH1004-M4, PiH1005-M1, PiH1005-M2, PiH1005-M3, P iH1005-M4, PiH1006-M1, PiH1006-M2, PiH1006-M3, PiH1006-M4, PiH1007-M1, PiH1007-M2, PiH1007-M3, PiH1007-M4, PiH1008-M1, PiH1008-M2, PiH1008-M3, PiH1008-M4; and the anti-CLDN6 antibody is conjugated with VC-PAB-MMAE, GGFG-MMAE, VC-PAB-MMAF, GGFG-MMAF, VC-PAB-DXd, GGFG-DXd or VC-PAB-DM1, GGFG-DM1, CL2A-SN38. In some embodiments, this disclosure provides an antibody-drug conjugate, wherein the anti-CLDN6 antibody is selected from PiH1001, PiH1002, PiH1003, PiH1004, PiH1005, PiH1006, PiH1007, PiH1008 and PiH2001, PiH2004, PiH2005, PiH2006, PiH2007, PiH2008, PiH2009, PiH2010, PiH2011, PiH2012, PiH2012-1; and the anti-CLDN6 antibody is conjugated to MC-VC-PAB-MMAE, MC-GGFG-MMAE, MC-VC-PAB-MMAF, MC-GGFG-MMAF, MC-VC-PAB-DXd, MC-GGFG-DXd, MC-VC-PAB-DM1 or MC-GGFG-DM1. In some embodiments, this disclosure provides an antibody-drug conjugate, wherein the anti-CLDN6 antibody is selected from PiH1001-M1, PiH1001-M2, PiH1001-M3, PiH1001-M4, PiH1002-M1, PiH1002-M2, PiH1002-M3, PiH1002-M4, PiH1003-M1, PiH1003-M2, PiH1003-M3, PiH1003-M4, PiH1004-M1, PiH1004-M2, PiH1004-M3, PiH1004-M4, PiH1005-M1, PiH1005-M2, PiH1005-M3, PiH1005- M4, PiHl006-M1, PiH1006-M2, PiH1006-M3, PiH1006-M4, PiH1007-M1, PiH1007-M2, PiH1007-M3, PiH1007-M4, PiH1008-M1, PiH1008-M2, PiH1008-M3, PiH1008-M4; and the anti-CLDN6 antibody is conjugated with MC-VC-PAB-MMAE, MC-GGFG-MMAE, MC-VC-PAB-MMAF, MC-GGFG-MMAF, MC-VC-PAB-DXd, MC-GGFG-DXd, MC-VC-PAB-DM1 or MC-GGFG-DM. On the other hand, this disclosure provides a pharmaceutical composition or kit comprising the antibody-drug conjugate as described above, and a pharmaceutically acceptable carrier, diluent, and / or excipient. In another aspect, this disclosure provides a method for preventing or treating diseases associated with CLDN6 expression, comprising administering an effective amount of the antibody-drug conjugate or the pharmaceutical composition as described above to a subject in need. In some implementations, the prevention of CLDN6 expression-related diseases includes the prevention of resistance, relapse, and metastasis of CLDN6 expression-related diseases. In some implementations, the CLDN6 expression-related disease is cancer, and the prevention of CLDN6 expression-related diseases includes preventing cancer resistance, recurrence, and metastasis. In some implementations, the disease associated with CLDN6 expression is cancer, including primary cancer, advanced cancer, metastatic cancer, recurrent cancer, or a combination thereof. In some implementations, the disease associated with CLDN6 expression is cancer, preferably selected from one or more of the following: ovarian cancer, lung cancer, gastric cancer, breast cancer, liver cancer, pancreatic cancer, skin cancer, malignant melanoma, head and neck cancer, sarcoma, bile duct cancer, bladder cancer, kidney cancer, colon cancer, placental choriocarcinoma, teratoma, cervical cancer, testicular cancer, uterine carcinosarcoma, endometrial cancer, and brain cancer. In some implementations, the diseases associated with CLDN6 expression are selected from one or more of ovarian cancer, testicular cancer, uterine carcinosarcoma, endometrial cancer, ovarian teratoma, gastric cancer, liver cancer, lung cancer (e.g., non-small cell lung cancer), and cholangiocarcinoma. In some embodiments, the disease associated with CLDN6 expression is a fibrotic disease, preferably selected from one or more of fibrosis of the lungs, liver, colon, gallbladder, and stomach, and more preferably selected from one or more of hepatitis, pulmonary fibrosis, liver fibrosis, cirrhosis, scleroderma, and biliary atresia. In some implementations, the subject is a mammal, preferably a human. In another aspect, this disclosure provides the use of the antibody-drug conjugates or pharmaceutical compositions or kits described above in the preparation of medicaments for the prevention or treatment of diseases associated with CLDN6 expression, as described above. Attached Figure Description This disclosure can be more fully understood with reference to the following figures. Figure 1 shows the binding affinity of the chimeric antibody to HEK293T-CLDN6. Figure 2 shows the bonding strength of 20A3-2A7 on HEK293T-CLDN6. Figure 3 shows the binding affinity of the improved chimeric monoclonal antibody RecA101 to HEK293T-CLDN6. Figure 4 shows the binding affinity of the humanized antibody based on 51C10H4 to HEK293T-CLDN6. Figure 5 shows the binding affinity of the humanized antibody based on 54B5A7 to HEK293T-CLDN6. Figure 6 shows the binding affinity of the chimeric antibody to HEK293T-CLDN9. Figure 7 shows the bonding strength of 20A3-2A7 in HEK293T-CLDN9. Figure 8 shows the binding affinity of the improved chimeric monoclonal antibody RecA101 to HEK293T-CLDN9. Figure 9 shows the binding affinity of the chimeric antibody to HEK293T-CLDN3. Figure 10 shows the bonding strength of 20A3-2A7 in HEK293T-CLDN3. Figure 11 shows the binding affinity of the chimeric antibody to HEK293T-CLDN4. Figure 12 shows the bonding strength of 20A3-2A7 on HEK293T-CLDN4. Figure 13 shows the binding results of the 51C10H4 and 54B5A7 chimeric antibodies with cell lines HEK293T-CLDN6, HEK293T-CLDN9, HEK293T-CLDN3, and HEK293T-CLDN4 at a concentration of 5 μg / mL. Figure 14 shows the results of the chimeric antibody binding on CHO-K1-mouse CLDN6 cells. Figure 15 shows the results of 20A3-2A7 binding on CHO-K1- mouse CLDN6 cells. Figure 16 shows the results of the chimeric antibody binding on CHO-K1-Cyno CLDN6 cells. Figure 17 shows the results of 20A3-2A7 binding on CHO-K1-Cyno CLDN6 cells. Figure 18 shows the binding of a humanized antibody based on 51C10H4 to cells overexpressing mouse CLDN6. Figure 19 shows the binding of a humanized antibody based on 51C10H4 to cells overexpressing monkey CLDN6. Figure 20 shows the binding of a humanized antibody based on 54B5A7 to cells overexpressing mouse CLDN6. Figure 21 shows the binding of a humanized antibody based on 54B5A7 to cells overexpressing monkey CLDN6. Figure 22 shows the binding affinity between the chimeric antibody and HepG2. Figure 23 shows the bonding force between 20A3-2A7 and HepG2. Figure 24 shows the binding affinity of the improved chimeric monoclonal antibody RecA101 to HepG2. Figure 25 shows the binding affinity of the humanized antibody based on 51C10H4 to HepG2. Figure 26 shows the binding affinity of the humanized antibody based on 54B5A7 to HepG2. Figure 27 shows the binding affinity of the humanized antibody based on 54B5A7 to HepG2. Figure 28 shows the binding affinity between the chimeric antibody and PA-1. Figure 29 shows the bonding force between 20A3-2A7 and PA-1. Figure 30 shows the binding affinity of the humanized antibody based on 51C10H4 to PA-1. Figure 31 shows the binding affinity of the humanized antibody based on 54B5A7 to PA-1. Figure 32 illustrates antibody-dependent cytotoxicity. Figure 33 illustrates complement-dependent cytotoxicity. Figure 34 shows the inhibitory effect of mAb / DT3C-conjugate on PA-1 cells. Figure 35 shows the binding affinity of the improved antibody to CHO-K1-CLDN6. Figure 36 shows the binding affinity of antibodies PiH2012, PiH1004, AB3-7, and 1gG1 to human ovarian cancer cells OVCA429. Figure 37 shows the binding affinity of antibodies PiH2012, PiH1004, AB3-7, and 1gG1 to human gastric cancer cells MKN7. Figure 38 shows the DAR value detection spectrum of the ADC molecule PiH1004-MMAE. Figure 39 shows the DAR value detection spectrum of the ADC molecule PiH1004-DXd. Figure 40 shows the binding force between the ADC molecule and PA-1. Figure 41 shows the binding force between the ADC molecule and HepG2. Figure 42 illustrates the cytotoxic effect of ADC molecules on PA-1. Figure 43 illustrates the cytotoxic effect of ADC molecules on OVCA429. Figure 44 illustrates the cytotoxic effect of ADC molecules on Huh7. Figure 45 illustrates the cytotoxic effect of ADC molecules on MKN7. Figure 46 illustrates the cytotoxic effect of ADC molecules on HEK293T-CLDN6. Figure 47 shows the anti-tumor experimental results of ADC molecules in the mouse PA-1 CDX model. Figure 48 shows the anti-tumor experimental results of ADC molecules in the CDX model of mouse OV90. Figure 49 shows the results of mouse weight changes in the OV90 CDX model of mice with ADC molecules. Figure 50 shows the anti-tumor experimental results of ADC molecules in the CDX model of mouse HepG2. Figure 51 shows the results of changes in mouse body weight in the CDX model of mouse HepG2 with ADC molecules. Figure 52 shows the anti-tumor experimental results of ADC molecules in a mouse PDX model of human CLDN6-positive ovarian cancer. Figure 53 shows the results of ADC molecule changes in mouse body weight in a PDX model of human CLDN6-positive ovarian cancer. Detailed Implementation To enable those skilled in the art to better understand the solutions disclosed herein, the technical solutions in the embodiments of this disclosure will be clearly and completely described below. Obviously, the described embodiments are merely some, not all, of the embodiments disclosed herein. What is disclosed herein are specific illustrative embodiments that verify the principles of this disclosure. It should be emphasized that this disclosure is not limited to the specific embodiments illustrated herein. Furthermore, any section headings used herein are not to be construed as limiting the described subject matter. Unless otherwise defined herein, scientific and technical terms used in conjunction with this disclosure will have the meaning commonly understood by one of ordinary skill in the art. Furthermore, unless the context otherwise requires, singular terms shall include plural forms, and plural terms shall include singular forms. More specifically, as used in this specification and the appended claims, unless the context otherwise clearly indicates, the singular forms “a,” “an,” and “the” include plural indicators. In this application, unless otherwise stated, the use of “or” means “and / or.” Furthermore, the use of the term “comprising” and other forms such as “including” and “containing” is not restrictive. Moreover, the scope provided in the specification and the appended claims includes all values ​​between endpoints. definition To better understand this disclosure, definitions and explanations of relevant terms are provided below. As used herein, the term "antibody" or "Ab" generally refers to a Y-shaped tetrameric protein comprising two heavy chains (H) and two light chains (L) held together by covalent disulfide bonds and non-covalent interactions. The light chains of an antibody can be classified as K or λ light chains. The heavy chains can be classified as μ, δ, γ, α, or ε, which define the antibody isotype as IgM, IgD, IgG, IgA, or IgE, respectively. In both the light and heavy chains, the variable region is linked to the constant region via a "J" region of about 12 or more amino acids, and the heavy chain also contains a "D" region of about 3 or more amino acids. Each heavy chain consists of a heavy chain variable region (VH) and a heavy chain constant region (CH). The heavy chain constant region consists of three domains (CH1, CH2, and CH3). Each light chain consists of a light chain variable region (VL) and a light chain constant region (CL). The VH and VL regions can be further divided into hypervariable regions (called complementarity-determining regions, or CDRs) separated by relatively conserved regions (called frame regions, or FRs). Each VH and VL consists of three CDRs and four FRs in the following order: FR1, CDR1, FR2, CDR2, FR3, CDR3, and FR4 from the N-terminus to the C-terminus. The variable regions (VH and VL) of each heavy / light chain pair form antigen-binding sites / parts, respectively. The distribution of amino acids in various regions or domains follows the numbering definitions of common systems such as Kabat, IMGT, or Chothia. In specific embodiments of this disclosure, the CDR sequence is determined using the numbering definitions of the Kabat system. Antibodies can have different antibody isotypes, such as IgG (e.g., IgG1, IgG2, IgG3, or IgG4 isotypes), IgA1, IgA2, IgD, IgE, or IgM antibodies. Antibodies in this disclosure also include antigen-binding moieties. An antigen-binding moiety refers to a polypeptide containing a portion / fragment of a full-length antibody that retains the ability to specifically bind to an antigen that the full-length antibody specifically binds to, and / or competes with the full-length antibody for binding to the same antigen. Under certain conditions, antigen-binding moieties include Fab, Fab′, F(ab′)2, Fd, Fv, dAb, and complementarity-determining region (CDR) fragments, single-chain antibodies (e.g., scFv), chimeric antibodies, biantibodies, and such polypeptides containing at least a portion of an antibody sufficient to confer specific antigen-binding ability. The antigen-binding moiety of an antibody can be obtained from a given antibody using conventional techniques known to those skilled in the art (e.g., recombinant DNA technology or enzymatic or chemical cleavage methods) and specificity can be screened in the same manner as for the intact antibody. As used herein, the term "isotype" refers to an antibody class (e.g., IgM or IgG1) encoded by a heavy chain constant region gene. As used herein, the term "monoclonal antibody" or "mAb" refers to an antibody molecule / formulation consisting of a single molecule. Monoclonal antibodies exhibit single binding specificity and affinity for a specific epitope. The antibodies disclosed herein may be derived from various species, including but not limited to mice, rats, rabbits, guinea pigs, and humans. As used herein, the term "epitope" refers to an antigenic determinant in a molecule, meaning a portion of the molecule that is recognized by the immune system (e.g., by antibodies), such as a discontinuous three-dimensional site on an antigen recognized by the immune system. In this disclosure, the epitopes shown are preferably derived from CLDN proteins, more preferably from CLDN6 proteins. As used herein, the term "chimeric antibody" refers to an antibody in which the variable region sequence is derived from one species and the constant region sequence is derived from another species, such as an antibody in which the variable region sequence is derived from a mouse antibody and the constant region sequence is derived from a human antibody. The term "humanized antibody" refers to an antibody in which a CDR sequence / antigen-binding portion or site derived from another mammalian species, such as a mouse, has been transplanted onto a human frame sequence. Furthermore, additional frame region modifications can be performed within the human frame sequence. As used herein, the term "CLDN" refers to Claudins, including CLDN6, CLDN9, CLDN4 and CLDN3, preferably human CLDN. As used herein, the term “anti-CLDN6 antibody” or “CLDN6 antibody” refers to an antibody that, as defined herein, is capable of binding to CLDN6 or to cells expressing CLDN6. As used herein, the term "specific binding" refers to a non-random binding reaction between two molecules, such as the reaction between an antibody and its target antigen. In some embodiments, an antibody that specifically binds to an antigen (or an antibody that is specific to an antigen) means that the antibody binds to an antigen at a concentration of less than about 10. -5 M, for example, less than approximately 10 -6 M, 10 -7 M, 10 -8 M, 10 -9 M or 10 -10 The antigen is bound to an M or smaller KD value. As used herein, the term "KD" or "Kd" refers to the equilibrium dissociation constant, i.e., the k-dissociation constant between the antigen-binding protein and CLDN6. off / k on The KD value is related to the concentration of the antigen-binding protein (the amount of antigen-binding protein required for a specific experiment), and the lower the KD value (the lower the concentration), the higher the affinity of the antigen-binding protein. In all respects, the binding strength of the antigen-binding protein to CLDN6 can be described in terms of KD. In all respects, the KD of the antigen-binding protein presented herein is approximately 10.-5 M, 10 -6 M, 10 -7 M, 10 -8 M, 10 -9 M or 10 -10 M or smaller. As used herein, the term “EC50” refers to half-maximum effective concentration or half-maximum effective activity. As used herein, the term "separated" refers to a state obtained artificially from the natural state. If a "separated" substance or component exists naturally, it may be due to changes in its natural environment, separation of the substance from its natural environment, or both. For example, if an unseparated polynucleotide or polypeptide exists naturally within a living organism, the same high-purity polynucleotide or polypeptide separated from that natural state is called a separated polynucleotide or polypeptide. The term "separated" does not exclude either artificially created or synthetic substances, nor does it exclude other impurities that do not affect the activity of the separated substance. As used herein, the term "isolated antibody" is intended to refer to an antibody that is substantially free of other antibodies with different antigen specificities (e.g., an isolated antibody that specifically binds to the CLDN6 protein is substantially free of antibodies that specifically bind to antigens other than the CLDN6 protein). However, isolated antibodies that specifically bind to the human CLDN6 protein may be cross-reactive to other antigens such as CLDN6 proteins from other species or other members of the CLDN family. Furthermore, isolated antibodies may be substantially free of other cellular material and / or chemicals. As used herein, the term "vector" refers to a nucleic acid medium in which polynucleotides can be inserted. When a vector allows the expression of a protein encoded by the polynucleotides inserted therein, the vector is called an expression vector. The vector can be transformed, transduced, or transfected into a host cell to express the carried genetic material elements in the host cell. Vectors are well known to those skilled in the art and include, but are not limited to, plasmids, bacteriophages, granules, artificial chromosomes such as yeast artificial chromosomes (YAC), bacterial artificial chromosomes (BAC), or P1-derived artificial chromosomes (PAC); bacteriophages such as λ phage or M13 phage; and animal viruses. Animal viruses that can be used as vectors include, but are not limited to, retroviruses (including lentiviruses), adenoviruses, adeno-associated viruses, herpesviruses (such as herpes simplex virus), poxviruses, baculoviruses, papillomaviruses, and multivacuolar papillomaviruses (such as SV40). Vectors may contain multiple elements for controlling expression, including, but not limited to, promoter sequences, transcription initiation sequences, enhancer sequences, selection elements, and reporter genes. Additionally, vectors may contain an origin of replication. As used herein, the term "host cell" refers to a cellular system that can be engineered to produce a target protein, protein fragment, or peptide. Host cells include, but are not limited to, cultured cells, such as mammalian cultured cells derived from rodents (rats, mice, guinea pigs, or hamsters), such as CHO, BHK, NSO, SP2 / 0, YB2 / 0; or human tissue or hybridoma cells, yeast cells, and insect cells, as well as cells contained within transgenic animals or cultured tissues. The term covers not only the specific test cell but also its progeny. Because certain modifications can occur in subsequent generations due to mutations or environmental influences, such progeny may differ from the parent cell but are still included within the scope of the term "host cell." As used herein, the term "identity" refers to the relationship between the sequences of two or more polypeptide molecules or two or more nucleic acid molecules, determined by alignment and comparison of sequences. "Percentage identity" refers to the percentage of identical residues among amino acids or nucleotides in the compared molecules, calculated based on the size of the smallest molecule being compared. For these calculations, gaps in the alignment (if any) are preferably addressed using a specific mathematical model or computer program (i.e., an "algorithm"). Methods that can be used to calculate the identity of aligned nucleic acids or peptides include those described in Computational Molecular Biology (Lesk, AM, ed.), 1988, New York: Oxford University Press; Biocomputing Informatics and Genome Projects (Smith, DW, ed.), 1993, New York: Academic Press; Computer Analysis of Sequence Data, Part I (Griffin, AM, and Griffin, HG, eds.), 1994, New Jersey: Humana Press; von Heinje, G., 1987, Sequence Analysis in Molecular Biology, New York: Academic Press; Sequence Analysis Primer (Gribskov, M. and Devereux, J., eds.), 1991, New York: M. Stockton Press; and Carillo et al., 1988, SIAM J. Applied Math. 48: 1073. As used herein, the term "immunogenicity" refers to the ability of an organism to stimulate the formation of specific antibodies or sensitized lymphocytes. It refers not only to the property of an antigen to stimulate the activation, proliferation, and differentiation of specific immune cells to ultimately produce immune effector substances such as antibodies and sensitized lymphocytes, but also to the specific immune response of antibodies or sensitized T lymphocytes that can be formed in the organism's immune system after stimulation with an antigen. Immunogenicity is the most important characteristic of an antigen. Whether an antigen can successfully induce an immune response in the host depends on three factors: the nature of the antigen, the host's reactivity, and the immunization method. As used herein, the term "transfection" refers to the process of introducing nucleic acids into eukaryotic cells, particularly mammalian cells. Protocols and techniques used for transfection include, but are not limited to, lipid transfection and chemical and physical methods such as electroporation. Many transfection techniques are well known in the art and are disclosed herein. See, for example, Graham et al., 1973, Virology 52:456; Sambrook et al., 2001, Molecular Cloning: A Laboratory Manual, ibid.; Davis et al., 1986, Basic Methods in Molecular Biology, Elsevier; Chu et al., 1981, Gene 13:197. In one specific embodiment of this disclosure, the human XO40 gene is transfected into 293F cells. As used herein, the terms “hybridoma” and “hybridoma cell line” are used interchangeably. When referring to the terms “hybridoma” and “hybridoma cell line,” they also include subclones and progeny cells of the hybridoma. As used herein, unless otherwise specified, the term “expression” includes the production of DNA or RNA or the production of proteins / peptides, including transient or stable expression, as well as “abnormal expression” or “partial expression”. For the vector expressing the antibody, a vector type in which the antibody heavy chain and light chain exist in different vectors or a vector type in which the heavy chain and light chain exist in the same vector can be used. As used herein, the term “SPR” or “surface plasmon resonance” refers to and includes optical phenomena that allow the analysis of real-time biospecific interactions by detecting changes in protein concentration within a biosensor matrix, for example using BIAcore systems (Pharmacia Biosensor AB, Uppsala, Sweden, and Piscataway, NJ). As used herein, the term "fluorescence-activated cell sorting" or "FACS" refers to a specific type of flow cytometry. It provides a method for sorting a heterogeneous mixture of biological cells, one cell at a time, into two or more containers based on the specific light scattering and fluorescence characteristics of each cell (FlowMetric. "Sorting Out Fluorescence Activated Cell Sorting". 2017-11-09). Instruments used to perform FACS are known to those skilled in the art and are commercially available to the public. Examples of such instruments include the FACS Star Plus, FACScan, and FACSort instruments from Becton Dickinson (Foster City, Calif.), the Epics C from Coulter Epics Division (Hialeah, FLa), and the MoFlo from Cytomation (Colorado Springs, Colo.). As used herein, the term "immune effector function" includes any function mediated by components of the immune system that results in the inhibition of tumor growth and / or tumorigenesis, as well as the inhibition of tumor dissemination and metastasis. Preferably, the immune effector function results in the killing of tumor cells. Preferably, the immune effector function in this disclosure is an antibody-mediated effector function. Such functions include complement-dependent cytotoxicity (CDC), antibody-dependent cell-mediated cytotoxicity (ADCC), induction of apoptosis in cells carrying tumor-associated antigens (e.g., by binding of antibodies to surface antigens), and / or inhibition of the proliferation of cells carrying tumor-associated antigens, preferably ADCC and / or CDC. Antibodies can also exert their effects simply by binding to tumor-associated antigens on the surface of tumor cells. For example, antibodies can block the function of tumor-associated antigens or induce apoptosis simply by binding to tumor-associated antigens on the surface of tumor cells. As used herein, the term "antibody-dependent cell-mediated cytotoxicity" or "ADCC" refers to a cytotoxic form in which secreted Ig binds to Fc receptors (FcRs) present on certain cytotoxic cells (e.g., natural killer (NK) cells, neutrophils, and macrophages), enabling these cytotoxic effector cells to specifically bind to target cells carrying antigens and subsequently kill the target cells with cytotoxins. Antibodies "arm" cytotoxic cells and are absolutely necessary for this killing. The primary cells mediating ADCC, NK cells, express only FcγRIII, while monocytes express FcγRI, FcγRII, and FcγRIII. FcR expression on hematopoietic cells is summarized in Table 3 on page 464 of Ravetch and Kinet, Annu. Rev. Immunol 9:457-92 (1991). To assess the ADCC activity of molecules of interest, in vitro ADCC assays can be performed, such as those described in US Patent Nos. US5,500,362 or US5,821,337. Effector cells that can be used for such assays include peripheral blood mononuclear cells (PBMCs) and natural killer (NK) cells. Optionally or additionally, the ADCC activity of the molecule of interest can be assessed in vivo, for example in animal models such as those published by Clynes et al. in PNAS (USA) 95:652-656 (1998). The term “complement-dependent cytotoxicity” or “CDC” refers to the lysis of target cells in the presence of complement. Activation of the classical complement pathway is initiated by the binding of the first component (C1q) of the complement system to an antibody (appropriate subclass) that binds to its homologous antigen. To assess complement activation, a CDC assay can be performed, for example, as described in Gazzano-Santoro et al., J. Immunol. Methods 202:163 (1996). The term “subject” includes any mammal, such as a human or a non-human animal, preferably a human. As used in this article, the term “cancer” refers to any tumor or malignant cell growth, proliferation, or metastasis that causes medical conditions, including solid tumors and non-solid tumors such as leukemia. The terms "treatment" and "curing" as used in this article generally refer to treatments and therapies for humans or animals that achieve some desired therapeutic effect, such as inhibiting disease progression, including a slowdown in the rate of progression, a halt in the rate of progression, disease regression, disease improvement, and disease cure. Treatment as a preventative measure (i.e., prevention) is also included. For cancer, "treatment" may refer to inhibiting or slowing the growth, proliferation, or metastasis of tumors or malignant cells, or some combination thereof. For tumors, "treatment" includes removing all or part of the tumor, inhibiting or slowing tumor growth and metastasis, preventing or delaying tumor development, or some combination thereof. As used herein, the term "therapeutic effective amount" refers to an amount of an active compound or a material, composition, or dosage form containing the active compound that, when administered according to the desired treatment regimen, is effective in producing certain desired therapeutic effects commensurate with a reasonable benefit / risk ratio. For example, when used in conjunction with the treatment or detection of an associated disease or condition, "effective amount" or "effective dose" refers to the amount or concentration of an antibody or its antigen-binding portion that is effective in treating or detecting said disease or condition. As used herein, the term “prevention” or “avoidance” in relation to a disease condition in mammals refers to the prevention or delay of the onset of the disease or the prevention of its clinical or subclinical manifestations. As used in this article, “inhibition” means the ability to cause a reduction, such as a reduction in the level of cell proliferation, including a reduction of 5% or more, 10% or more, 20% or more, 50% or more, 75% or more, as well as complete or near-complete inhibition, i.e., a reduction to 0 or near-complete reduction to 0. As used herein, the term "pharmaceutically acceptable" means that the carrier, diluent, excipient and / or its salts are chemically and / or physically compatible with other components in the formulation and physiologically compatible with the recipient. As used herein, the term "pharmaceutically acceptable carrier, diluent, and / or excipient" means a carrier, diluent, and / or excipient that is pharmacologically and / or physiologically compatible with the subject and the active agent and is well known in the art (see, for example, Remington's Pharmaceutical Sciences. Edited by Gennaro AR, 19). th (ed. Pennsylvania: Mack Publishing Company, 1995), and includes, but is not limited to, pH adjusters, surfactants, adjuvants, and ionic strength enhancers. For example, pH adjusters include, but are not limited to, phosphate buffers; surfactants include, but are not limited to, cationic, anionic, or nonionic surfactants, such as Tween-80; and ionic strength enhancers include, but are not limited to, sodium chloride. As used herein, the term "adjuvant" refers to a nonspecific immune enhancer that, when delivered to an organism along with or before an antigen, can enhance the organism's immune response to the antigen or alter the type of immune response. Various adjuvants exist, including but not limited to aluminum adjuvants (e.g., aluminum hydroxide), Freund's adjuvants (e.g., complete and incomplete Freund's adjuvants), Corynebacterium breve, lipopolysaccharides, and cytokines. Freund's adjuvant is currently the most commonly used adjuvant in animal experiments. Aluminum hydroxide adjuvants are more commonly used in clinical trials. Anti-CLDN6 antibody In some aspects, this disclosure includes isolated antibodies or antigen-binding portions thereof. In some specific embodiments, "isolated antibody" in this disclosure refers to the "anti-CLDN6 antibody" or "CLDN6 antibody" of this disclosure. In the context of this application, "antibody" can include polyclonal antibodies, monoclonal antibodies, chimeric antibodies, humanized and primate-derived antibodies, CDR transplantation antibodies, human antibodies, recombinant antibodies, intracellular antibodies, multispecific antibodies, bispecific antibodies, monovalent antibodies, multivalent antibodies, anti-idiotype antibodies, synthetic antibodies, including mutant proteins and variants thereof, modified antibodies; and derivatives thereof (including Fc fusion proteins and other modifications), as well as any other immunoreactive molecule that exhibits preferential association or binding to the CLDN6 protein. Furthermore, unless the context otherwise requires, the term also includes all classes of antibodies (i.e., IgA, IgD, IgE, IgG, and IgM) and all subclasses (i.e., IgG1, IgG2, IgG3, IgG4, IgA1, and IgA2). In a preferred embodiment, the antibody is a monoclonal antibody. In a more preferred embodiment, the antibody is a chimeric monoclonal antibody or a humanized monoclonal antibody or a modified chimeric monoclonal antibody. In some embodiments, the antibody comprises: (1)CDRH1, which contains the sequence X1YNMH or is composed of the sequence, where X1 is selected from D or S; (2) CDRH2, which contains the sequence YX1X2PX3X4X5X6TX7YNQKFKG or is composed of the sequence, where X1 is selected from V or I, X2 is selected from N or Y, X3 is selected from N or G, X4 is selected from N or Q or S or A, X5 is selected from A or G or D or Q or S, X6 is selected from A or G, and X7 is selected from S or N; (3) CDRH3, which contains the sequence WX1X2YVYYYGX3DY or SEQ ID NO: 23 or is composed of it, X1 is selected from D or E or S or G, X2 is selected from A or G or S or D or Q, and X3 is selected from L or M; (4) CDRL1, which contains or consists of the sequence SEQ ID NO: 27 or SEQ ID NO: 29; (5) CDRL2, which contains or consists of the sequence SEQ ID NO: 30 or SEQ ID NO: 31; and (6) CDRL3, which contains or consists of the sequence QQYWX1TPYT or SEQ ID NO: 40, where X1 is selected from S or N; Or the antibody may contain: (1) CDRH1, which contains or consists of SEQ ID NO: 5; (2) CDRH2, which contains or consists of SEQ ID NO: 12, or contains or consists of the sequence YX1NPNNGAX2X3YNQKFKG, where X1 is selected from A, I, L or V, X2 is selected from S or T, and X3 is selected from S or N; preferably, CDRH2 contains or consists of the sequence SEQ ID NO: 12, 91, 92, 93, 94, 119, 120, 121, 122, 123, 124 or 125; (3) CDRH3, which contains or consists of SEQ ID NO: 20, or contains the sequence WDGYXiYYYGX2DX3 or consists of the sequence, wherein X1 is selected from V or S, X2 is selected from V, L or M, and X3 is selected from Y or F; preferably, CDRH3 contains or consists of the sequence SEQ ID NO: 20, 95, 96, 97, 126, 127, 128, 129, 130, or 131; (4) CDRL1, which contains or is composed of the sequence SEQ ID NO: 27, or contains or is composed of the sequence KASX1HX2NX3WLA, wherein X1 is selected from E or D, X2 is selected from I or V, and X3 is selected from H or Q; preferably, CDRL1 contains or is composed of SEQ ID NO: 27, 98, 99, 100, 132, 133, 134, or 135; (5) CDRL2, which contains or consists of SEQ ID NO: 31, or which contains or consists of SEQ ID NO: 101; and (6) CDRL3, which comprises or is composed of SEQ ID NO: 37, or comprises or is composed of QQYX1X2TPYX3, wherein X1 is selected from W or G, X2 is selected from S, H or N, and X3 is selected from S or T; preferably, CDRL3 comprises or is composed of SEQ ID NO: 37, 102, 103, 104, 136, 137, 138, 139, 140, 141 or 142; Or the antibody may contain: (1) CDRH1, which contains or consists of the sequence SYXiIX2, wherein X1 is selected from N or G and X2 is selected from H or S; (2) CDRH2, which contains or consists of the sequence X1IYPX2X3GX4TX5X6NEX7FKG, wherein X1 is selected from Y or E, X2 is selected from G or R, X3 is selected from N or S, X4 is selected from G or N, X5 is selected from K or Y, X6 is selected from Y or H, and X7 is selected from R or K. (3) CDRH3, which contains the sequence SEQ ID NO: 16 or SEQ ID NO: 19; (4) CDRL1, which contains the sequence SEQ ID NO: 24 or SEQ ID NO: 26, or is composed of SEQ ID NO: 24 or SEQ ID NO: 26; (5) CDRL2, which contains the sequence X1X2SNLX3S or is composed of the sequence, wherein X1 is selected from L or G, X2 is selected from A or T, and X3 is selected from E or A; and (6) CDRL3, which contains the sequence SEQ ID NO: 34 or SEQ ID NO: 179, or is composed of SEQ ID NO: 34 or SEQ ID NO: 179; Or the antibody may contain: (1) CDRH1, which contains or consists of the sequence X1YX2MS, wherein X1 is selected from S or N and X2 is selected from G or A; (2) CDRH2, which contains the sequence TISX1GGSYTX2YPDX3X4KG or is composed of the sequence, wherein X1 is selected from S or D, X2 is selected from Y or S, X3 is selected from S or N, and X4 is selected from V or I; (3) CDRH3, which contains the sequence SEQ ID NO: 17 or SEQ ID NO: 18, or is composed of SEQ ID NO: 17 or SEQ ID NO: 18; (4) CDRL1, which contains the sequence SEQ ID NO: 25 or consists of SEQ ID NO: 25; (5) CDRL2, which contains the sequence X1X2TSLET or is composed of the sequence, wherein X1 is selected from G or A, and X2 is selected from A or T; and (6) CDRL3, which contains the sequence QQYWS X1PX2T or is composed of the sequence, wherein X1 is selected from T or F and X2 is selected from P or R; In some embodiments, the antibody comprises: (1)CDRH1, which contains or is composed of the sequence X1YNMH, where X1 is selected from D or S; (2) CDRH2, which contains the sequence YX1X2PX3X4X5X6TX7YNQKFKG or is composed of the sequence, where X1 is selected from V or I, X2 is selected from N or Y, X3 is selected from N or G, X4 is selected from N or Q or S or A, X5 is selected from A or G or D or Q or S, X6 is selected from A or G, and X7 is selected from S or N; (3) CDRH3, which contains the sequence WX1X2YVYYYGX3DY or SEQ ID NO: 23 or any of these sequences, where X1 is selected from D or E or S or G, X2 is selected from A or G or S or D or Q, and X3 is selected from L or M; (4) CDRL1, which contains the sequence SEQ ID NO: 27 or SEQ ID NO: 29 or is composed of either of them; (5) CDRL2, which contains the sequence SEQ ID NO: 30 or SEQ ID NO: 31 or consists of either of these sequences; and (6) CDRL3, which contains the sequence QQYWX1TPYT or SEQ ID NO: 40 or is composed of any of these sequences, wherein X1 is selected from S or N; Or the antibody may contain: (1) CDRH1, which contains the sequence SYX1IX2 or is composed of the sequence, where X1 is selected from N or G and X2 is selected from H or S; (2) CDRH2, which contains or consists of the sequence X1IYPX2X3GX4TX5X6NEX7FKG, where X1 is selected from Y or E, X2 is selected from G or R, X3 is selected from N or S, X4 is selected from G or N, X5 is selected from K or Y, X6 is selected from Y or H, and X7 is selected from R or K. (3) CDRH3, which contains the sequence SEQ ID NO: 16 or SEQ ID NO: 19 or is composed of either of these sequences; (4) CDRL1, which contains the sequence SEQ ID NO: 24 or SEQ ID NO: 26 or is composed of either of them; (5) CDRL2, which contains or consists of the sequence X1X2sNLX3S, where X1 is selected from L or G, X2 is selected from A or T, and X3 is selected from E or A; and (6) CDRL3, which contains the sequence SEQ ID NO: 34 or SEQ ID NO: 179 or is composed of either of these sequences; Or the antibody may contain: (1) CDRH1, which contains or consists of the sequence X1YX2MS, where X1 is selected from S or N and X2 is selected from G or A; (2) CDRH2, which contains the sequence TISX1GGSYTX2YPDX3X4KG or is composed of the sequence, where X1 is selected from S or D, X2 is selected from Y or S, X3 is selected from S or N, and X4 is selected from V or I. (3) CDRH3, which contains the sequence SEQ ID NO: 17 or SEQ ID NO: 18 or is composed of either of these sequences; (4) CDRL1, which contains or consists of the sequence SEQ ID NO: 25; (5) CDRL2, which contains the sequence X1X2TSLET or is composed of the sequence, where X1 is selected from G or A, and X2 is selected from A or T; and (6) CDRL3, which contains the sequence QQYWSX1PX2T or is composed of the sequence, where X1 is selected from T or F and X2 is selected from P or R. In some embodiments, the antibody comprises: (1) CDRH1, which contains or consists of the sequence SEQ ID NO: 5; (2) CDRH2, which contains the sequence YX1NPNX2X3ATX4YNQKFKG or is composed of the sequence, where X1 is selected from V or I, X2 is selected from N or Q or S or A, X3 is selected from A or G or D or Q or S, and X4 is selected from S or N. (3)CDRH3, which contains the sequence WDGYVYYYGX1DY or is composed of the sequence, where X1 is selected from L or M; (4) CDRL1, which contains or consists of the sequence SEQ ID NO: 27; (5) CDRL2, which contains or consists of the sequence SEQ ID NO: 31; and (6) CDRL3, which contains the sequence QQYWX1TPYT or is composed of the sequence, where X1 is selected from S or N. In some embodiments, the antibody comprises: (1) CDRH1, which contains or consists of the sequence SEQ ID NO: 5; (2)CDRH2, which contains the sequence YX1NPNNGATX2YNQKFKG or is composed of the sequence, where X1 is selected from V or I and X2 is selected from S or N; (3)CDRH3, which contains the sequence WDGYVYYYGX1DY or is composed of the sequence, where X1 is selected from L or M; (4) CDRL1, which contains the sequence sEQ ID NO: 27 or is composed of the sequence; (5) CDRL2, which contains or consists of the sequence SEQ ID NO: 31; and (6) CDRL3, which contains the sequence QQYWX1TPYT or is composed of the sequence, where X1 is selected from S or N. In some embodiments, the isolated anti-CLDN6 antibody or its antigen-binding moiety comprises a heavy chain variable region and a light chain variable region, wherein the heavy chain variable region comprises: (i) CDRH1, which comprises or consists of any of the sequences shown in SEQ ID NO: 1-5 and 7, or any of the sequences having at least 80%, 82%, 85%, 88%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% identity with SEQ ID NO: 1-5 and 7; (ii) CDRH2, comprising or consisting of any sequence shown in or composed of SEQ ID NO: 8-13, 15, 74-76, or any sequence or consisting of SEQ ID NO: 8-13, 15, 74-76 having at least 80%, 82%, 85%, 88%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% identity with SEQ ID NO: 8-13, 15, 74-76; and (iii) CDRH3, which comprises or consists of any sequence shown in SEQ ID NO: 16-21, 23, 77-78, or any sequence or consists of having at least 80%, 82%, 85%, 88%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% identity with SEQ ID NO: 16-21, 23, 77-78; The light chain variable region includes: (i) CDRL1, which comprises or consists of any of the sequences shown in SEQ ID NO: 24-27 and 29, or any of the sequences shown in SEQ ID NO: 24-27 and 29 having at least 80%, 82%, 85%, 88%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% identity with SEQ ID NO: 24-27 and 29; (ii) CDRL2, comprising or consisting of any sequence selected from or composed of any sequence shown in SEQ ID NO: 30-33, or any sequence having at least 80%, 82%, 85%, 88%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% identity with SEQ ID NO: 30-33; and (iii) CDRL3, which comprises or consists of any sequence selected from or composed of any sequence shown in SEQ ID NO: 34-38, 40 and 179, or any sequence or consisting of any sequence having at least 80%, 82%, 85%, 88%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% identity with SEQ ID NO: 34-38, 40 and 179. Variable regions and CDRs in antibody sequences can be identified according to general rules already developed in the art (as described above, such as the Kabat numbering system) or by comparing the sequence with a database of known variable regions. In other embodiments, the CDR amino acid sequence may have at least 80%, 82%, 85%, 88%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% identity with the corresponding sequence described above. As an illustrative example, the antibody may comprise CDRH1 having at least 80%, 82%, 85%, 88%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% sequence identity with CDRH1 as shown in SEQ ID NOs: 1-5 and 7. In some embodiments, the isolated antibody or its antigen-binding portion comprises: CDRH1 comprising or consisting of SEQ ID NO: 1; CDRH2 comprising or consisting of SEQ ID NO: 8; CDRH3 comprising or consisting of SEQ ID NO: 16; CDRL1 comprising or consisting of SEQ ID NO: 24; CDRL2 comprising or consisting of SEQ ID NO: 30; and CDRL3 comprising or consisting of SEQ ID NO: 34. In some embodiments, the isolated antibody or its antigen-binding portion comprises: CDRH1 comprising or consisting of SEQ ID NO: 2; CDRH2 comprising or consisting of SEQ ID NO: 9; CDRH3 comprising or consisting of SEQ ID NO: 17; CDRL1 comprising or consisting of SEQ ID NO: 25; CDRL2 comprising or consisting of SEQ ID NO: 31 and CDRL3 comprising or consisting of SEQ ID NO: 35. In some embodiments, the isolated antibody or its antigen-binding portion comprises: CDRH1 comprising or consisting of SEQ ID NO: 3; CDRH2 comprising or consisting of SEQ ID NO: 10; CDRH3 comprising or consisting of SEQ ID NO: 18; CDRL1 comprising or consisting of SEQ ID NO: 25; CDRL2 comprising or consisting of SEQ ID NO: 32; and CDRL3 comprising or consisting of SEQ ID NO: 36. In some embodiments, the isolated antibody or its antigen-binding portion comprises: CDRH1 comprising or consisting of SEQ ID NO: 4; CDRH2 comprising or consisting of SEQ ID NO: 11; CDRH3 comprising or consisting of SEQ ID NO: 19; CDRL1 comprising or consisting of SEQ ID NO: 26; CDRL2 comprising or consisting of SEQ ID NO: 33; and CDRL3 comprising or consisting of SEQ ID NO: 179. In some embodiments, the isolated antibody or its antigen-binding portion comprises: CDRH1 comprising or consisting of SEQ ID NO: 5; CDRH2 comprising or consisting of SEQ ID NO: 12; CDRH3 comprising or consisting of SEQ ID NO: 20; CDRL1 comprising or consisting of SEQ ID NO: 27; CDRL2 comprising or consisting of SEQ ID NO: 31; and CDRL3 comprising or consisting of SEQ ID NO: 37. In some embodiments, the isolated antibody or its antigen-binding portion comprises: CDRH1 comprising or consisting of SEQ ID NO: 5; CDRH2 comprising or consisting of SEQ ID NO: 13; CDRH3 comprising or consisting of SEQ ID NO: 21; CDRL1 comprising or consisting of SEQ ID NO: 27; CDRL2 comprising or consisting of SEQ ID NO: 31; and CDRL3 comprising or consisting of SEQ ID NO: 38. In some embodiments, the isolated antibody or its antigen-binding portion comprises: CDRH1 comprising or consisting of SEQ ID NO: 7; CDRH2 comprising or consisting of SEQ ID NO: 15; CDRH3 comprising or consisting of SEQ ID NO: 23; CDRL1 comprising or consisting of SEQ ID NO: 29; CDRL2 comprising or consisting of SEQ ID NO: 30; and CDRL3 comprising or consisting of SEQ ID NO: 40. In some embodiments, the isolated antibody or its antigen-binding portion comprises: CDRH1 comprising or consisting of SEQ ID NO: 5; CDRH2 comprising or consisting of SEQ ID NO: 12; CDRH3 comprising or consisting of SEQ ID NO: 20; CDRL1 comprising or consisting of SEQ ID NO: 27; CDRL2 comprising or consisting of SEQ ID NO: 31; and CDRL3 comprising or consisting of SEQ ID NO: 38. In some embodiments, the isolated antibody or its antigen-binding portion comprises: CDRH1 comprising or consisting of SEQ ID NO: 7; CDRH2 comprising or consisting of SEQ ID NO: 74; CDRH3 comprising or consisting of SEQ ID NO: 23; CDRL1 comprising or consisting of SEQ ID NO: 29; CDRL2 comprising or consisting of SEQ ID NO: 30; and CDRL3 comprising or consisting of SEQ ID NO: 40. In some embodiments, the isolated antibody or its antigen-binding portion comprises: CDRH1 comprising or consisting of SEQ ID NO: 5; CDRH2 comprising or consisting of SEQ ID NO: 75; CDRH3 comprising or consisting of SEQ ID NO: 20; CDRL1 comprising or consisting of SEQ ID NO: 27; CDRL2 comprising or consisting of SEQ ID NO: 31; and CDRL3 comprising or consisting of SEQ ID NO: 37. In some embodiments, the isolated antibody or its antigen-binding portion comprises: CDRH1 comprising or consisting of SEQ ID NO: 5; CDRH2 comprising or consisting of SEQ ID NO: 76; CDRH3 comprising or consisting of SEQ ID NO: 20; CDRL1 comprising or consisting of SEQ ID NO: 27; CDRL2 comprising or consisting of SEQ ID NO: 31; and CDRL3 comprising or consisting of SEQ ID NO: 37. In some embodiments, the isolated antibody or its antigen-binding portion comprises: CDRH1 comprising or consisting of SEQ ID NO: 5; CDRH2 comprising or consisting of SEQ ID NO: 12; CDRH3 comprising or consisting of SEQ ID NO: 77; CDRL1 comprising or consisting of SEQ ID NO: 27; CDRL2 comprising or consisting of SEQ ID NO: 31; and CDRL3 comprising or consisting of SEQ ID NO: 37. In some embodiments, the isolated antibody or its antigen-binding portion comprises: CDRH1 comprising or consisting of SEQ ID NO: 5; CDRH2 comprising or consisting of SEQ ID NO: 12; CDRH3 comprising or consisting of SEQ ID NO: 78; CDRL1 comprising or consisting of SEQ ID NO: 27; CDRL2 comprising or consisting of SEQ ID NO: 31; and CDRL3 comprising or consisting of SEQ ID NO: 37. According to this disclosure, referring to an antibody chain containing a specific CDR sequence (e.g., a specific CDR3 sequence) means that the specific CDR sequence forms a CDR region (e.g., a CDR3 region) of the antibody chain, that is, the CDR region is composed of the specific CDR sequence, or forms part of a CDR region (e.g., a CDR3 region of the antibody chain), that is, the CDR region contains the specific CDR sequence. In some embodiments, in the antibody or its antigen-binding portion, the heavy chain variable region, as described above, comprises any amino acid sequence of SEQ ID NO: 41-46, 48-60, 79-83 or a sequence thereof, or any amino acid sequence of SEQ ID NO: 41-46, 48-60, 79-83 having at least 80%, at least 82%, 85%, 88%, 90%, 91%, 92%, 93%, 94%, or at least 95%, 96%, 97%, 98%, 99% identity with the sequence of SEQ ID NO: 41-46, 48-60, 79-83; the light chain variable region comprises any amino acid sequence of SEQ ID NO: 61-66, 68-73 or a sequence thereof, or a sequence thereof having at least 80%, at least 82%, 85%, 88%, 90%, 90%, 91%, 92%, 93%, 94%, or at least 95%, 96%, 97%, 98%, 99% identity with the sequence of SEQ ID NO: 41-46, 48-60, 79-83; The sequences NO: 61-66 and 68-73 have at least 80%, at least 82%, 85%, 88%, 90%, 91%, 92%, 93%, 94%, or at least 95%, 96%, 97%, 98%, 99% identity with any amino acid sequence or a sequence composed of such sequences. In some embodiments, the isolated antibody or its antigen-binding portion comprises: (a) A heavy chain variable region comprising an amino acid sequence or being composed thereof that is at least 80% identical to the sequence of SEQ ID NO: 41, and a light chain variable region comprising an amino acid sequence or being composed thereof that is at least 80% identical to the sequence of SEQ ID NO: 61; or (b) a heavy chain variable region comprising or consisting of an amino acid sequence identical to at least 80% of the sequence of SEQ ID NO: 42 and a light chain variable region comprising or consisting of an amino acid sequence identical to at least 80% of the sequence of SEQ ID NO: 62; or (c) A heavy chain variable region comprising or consisting of an amino acid sequence identical to at least 80% of the sequence of SEQ ID NO: 43 and a light chain variable region comprising or consisting of an amino acid sequence identical to at least 80% of the sequence of SEQ ID NO: 63; or (d) A heavy chain variable region comprising or consisting of an amino acid sequence identical to at least 80% of the sequence of SEQ ID NO: 44, and a light chain variable region comprising or consisting of an amino acid sequence identical to at least 80% of the sequence of SEQ ID NO: 64; or (e) a heavy chain variable region comprising an amino acid sequence or being composed of an amino acid sequence identical to at least 80% of any of the sequences in SEQ ID NO: 45 or 80-83, and a light chain variable region comprising an amino acid sequence or being composed of an amino acid sequence identical to at least 80% of the sequence in SEQ ID NO: 65; or (f) a heavy chain variable region comprising or consisting of an amino acid sequence identical to at least 80% of the sequence of SEQ ID NO: 46 or 45, and a light chain variable region comprising or consisting of an amino acid sequence identical to at least 80% of the sequence of SEQ ID NO: 66; or (g) a heavy chain variable region comprising or consisting of an amino acid sequence identical to at least 80% of the sequence of SEQ ID NO: 48 or 79, and a light chain variable region comprising or consisting of an amino acid sequence identical to at least 80% of the sequence of SEQ ID NO: 68; or (h) a heavy chain variable region comprising an amino acid sequence or being composed of an amino acid sequence that is at least 80% identical to any of the sequences in SEQ ID NO: 49-52, and a light chain variable region comprising an amino acid sequence or being composed of an amino acid sequence that is at least 80% identical to any of the sequences in SEQ ID NO: 69; or (i) a heavy chain variable region comprising or consisting of an amino acid sequence that is at least 80% sequence identical to any of the sequences in SEQ ID NO: 49-52, and a light chain variable region comprising or consisting of an amino acid sequence that is at least 80% sequence identical to any of the sequences in SEQ ID NO: 70; or (j) a heavy chain variable region comprising an amino acid sequence identical to or consisting of at least 80% of the sequence of SEQ ID NO: 53 or 54, and a light chain variable region comprising an amino acid sequence identical to or consisting of at least 80% of the sequence of SEQ ID NO: 71; or (k) a heavy chain variable region comprising an amino acid sequence or being composed of any of the sequences in SEQ ID NO: 53-56 that is at least 80% sequence identical, and a light chain variable region comprising an amino acid sequence or being composed of an amino acid sequence that is at least 80% sequence identical, to any of the sequences in SEQ ID NO: 72; or (l) A heavy chain variable region comprising an amino acid sequence or being composed of any of the sequences in SEQ ID NO: 57-60 that is at least 80% sequence identical, and a light chain variable region comprising an amino acid sequence or being composed of any of the sequences in SEQ ID NO: 73 that is at least 80% sequence identical. In some embodiments, the antibody or its antigen-binding portion comprises: (a) A heavy chain variable region comprising or consisting of the amino acid sequence of SEQ ID NO: 41 and a light chain variable region comprising or consisting of the amino acid sequence of SEQ ID NO: 61; or (b) a heavy chain variable region comprising or consisting of the amino acid sequence of SEQ ID NO: 42 and a light chain variable region comprising or consisting of the amino acid sequence of SEQ ID NO: 62; or (c) A heavy chain variable region comprising or consisting of the amino acid sequence of SEQ ID NO: 43 and a light chain variable region comprising or consisting of the amino acid sequence of SEQ ID NO: 63; or (d) A heavy chain variable region comprising or consisting of the amino acid sequence of SEQ ID NO: 44 and a light chain variable region comprising or consisting of the amino acid sequence of SEQ ID NO: 64; or (e) a heavy chain variable region comprising or consisting of any of the amino acid sequences in SEQ ID NO: 45 or 80-83, and a light chain variable region comprising or consisting of the amino acid sequence in SEQ ID NO: 65; or (f) A heavy chain variable region comprising or consisting of the amino acid sequence of SEQ ID NO: 46 or 45 and a light chain variable region comprising or consisting of the amino acid sequence of SEQ ID NO: 66; or (g) A heavy chain variable region comprising or consisting of the amino acid sequence of SEQ ID NO: 48 or 79 and a light chain variable region comprising or consisting of the amino acid sequence of SEQ ID NO: 68; or (h) a heavy chain variable region comprising or consisting of any of the amino acid sequences in SEQ ID NO: 49-52 and a light chain variable region comprising or consisting of the amino acid sequence in SEQ ID NO: 69; or (i) a heavy chain variable region comprising or consisting of any of the amino acid sequences in SEQ ID NO: 49-52 and a light chain variable region comprising or consisting of the amino acid sequence in SEQ ID NO: 70; or (j) A heavy chain variable region comprising or consisting of the amino acid sequence of SEQ ID NO: 53 or 54 and a light chain variable region comprising or consisting of the amino acid sequence of SEQ ID NO: 71; or (k) a heavy chain variable region comprising or consisting of any of the amino acid sequences in SEQ ID NO: 53-56 and a light chain variable region comprising or consisting of the amino acid sequence in SEQ ID NO: 72; or (l) a heavy chain variable region comprising or consisting of any of the amino acid sequences in SEQ ID NO: 57-60 and a light chain variable region comprising or consisting of the amino acid sequence in SEQ ID NO: 73. In some embodiments, the isolated antibody or its antigen-binding moiety may contain conserved substitutions or modifications or replacements (e.g., conserved substitutions), deletions, or additions (e.g., substitutions, deletions, or additions of 1, 2, 3, 4, or 5 amino acids; or conserved substitutions of up to 20, 15, 10, or 5 amino acids) in the variable regions of the heavy and / or light chains, or have sequence identity of at least 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, or 100% with the antibody or antigen fragment from which it is derived. Amino acid deletion variants containing missing amino acids at the N-terminus and / or C-terminus of a protein are also referred to as N-terminal and / or C-terminal truncation variants. It is understood in the art that certain conserved sequence modifications that do not eliminate antigen binding can be made. See, for example, Brummell et al. (1993) Biochem 32: 1180-8; de Wildt et al. (1997) Prot. Eng. 10: 835-41; Komissarov et al. (1997) J. Biol. Chem. 272: 26864-26870; Hall et al. (1992) J. Immunol. 149: 1605-12; Kelley and O'Connell (1993) Biochem. 32: 6862-35; Adib-Conquy et al. (1998) Int. Immunol. 10: 341-6 and Beers et al. (2000) Clin. Can. Res. 6: 2835-43. In some embodiments, the antibody comprises: (1) CDRH1, which contains or consists of SEQ ID NO: 5; (2) CDRH2, which contains or consists of SEQ ID NO: 12, or contains or consists of the sequence YX1NPNNGAX2X3YNQKFKG, where X1 is selected from A, I, L or V, X2 is selected from S or T, and X3 is selected from S or N; preferably, CDRH2 contains or consists of the sequence SEQ ID NO: 12, 91, 92, 93, 94, 119, 120, 121, 122, 123, 124 or 125; (3) CDRH3, which contains or consists of SEQ ID NO: 20, or contains or consists of the sequence WDGYX1YYYGX2DX3, wherein X1 is selected from V or S, X2 is selected from V, L or M, and X3 is selected from Y or F; preferably, CDRH3 contains or consists of the sequence SEQ ID NO: 20, 95, 96, 97, 126, 127, 128, 129, 130, or 131; (4) CDRL1, which contains or consists of SEQ ID NO: 27, or contains the sequence KASX1HX2NX3WLA or consists of the sequence, wherein X1 is selected from E or D, X2 is selected from I or V, and X3 is selected from H or Q; preferably, CDRL1 contains or consists of SEQ ID NO: 27, 98, 99, 100, 132, 133, 134, or 135; (5) CDRL2, which contains or consists of SEQ ID NO: 31, or which contains or consists of SEQ ID NO: 101; and (6) CDRL3, which comprises or is composed of SEQ ID NO: 37, or comprises or is composed of QQYX1X2TPYX3, wherein X1 is selected from W or G, X2 is selected from S, H or N, and X3 is selected from S or T; preferably, CDRL3 comprises or is composed of SEQ ID NO: 37, 102, 103, 104, 136, 137, 138, 139, 140, 141 or 142. Preferably, the antibody comprises: (1) CDRH1, which contains or consists of SEQ ID NO: 5; (2) CDRH2, which contains or consists of SEQ ID NO: 12, or contains or consists of the sequence YX1NPNNGAX2X3YNQKFKG, where X1 is selected from A, I, L or V, X2 is selected from S or T, and X3 is selected from S or N; preferably, CDRH2 contains or consists of the sequence SEQ ID NO: 12, 91, 92, 93, 94, 119, 120, 121, 122, 123, 124 or 125; (3) CDRH3, which contains or consists of SEQ ID NO: 20; (4) CDRL1, which contains or consists of SEQ ID NO: 27; (5) CDRL2, which contains or consists of SEQ ID NO: 31; and (6) CDRL3, which contains or consists of SEQ ID NO: 37; Alternatively, the antibody may comprise: (1) CDRH1, which contains or consists of SEQ ID NO: 5; (2) CDRH2, which contains or consists of SEQ ID NO: 12; (3) CDRH3, which contains or consists of SEQ ID NO: 20, or contains the sequence WDGYX1YYYGX2DX3 or consists of the sequence, wherein X1 is selected from V or S, X2 is selected from V, L or M, and X3 is selected from Y or F; preferably, CDRH3 contains or consists of the sequence SEQ ID NO: 20, 95, 96, 97, 126, 127, 128, 129, 130, or 131; (4) CDRL1, which contains or consists of SEQ ID NO: 27; (5) CDRL2, which contains or consists of SEQ ID NO: 31; and (6) CDRL3, which contains or consists of SEQ ID NO: 37; Alternatively, the antibody may comprise: (1) CDRH1, which contains or consists of SEQ ID NO: 5; (2) CDRH2, which contains or consists of SEQ ID NO: 12; (3) CDRH3, which contains or consists of SEQ ID NO: 20; (4) CDRL1, which contains or consists of SEQ ID NO: 27, or contains the sequence KASX1HX2NX3WLA or consists of the sequence, wherein X1 is selected from E or D, X2 is selected from I or V, and X3 is selected from H or Q; preferably, CDRL1 contains or consists of SEQ ID NO: 27, 98, 99, 100, 132, 133, 134, or 135; (5) CDRL2, which contains or consists of SEQ ID NO: 31; and (6) CDRL3, which contains or consists of SEQ ID NO: 37; Alternatively, the antibody may comprise: (1) CDRH1, which contains or consists of SEQ ID NO: 5; (2) CDRH2, which contains or consists of SEQ ID NO: 12; (3) CDRH3, which contains or consists of SEQ ID NO: 20; (4) CDRL1, which contains or consists of SEQ ID NO: 27; (5) CDRL2, which contains or consists of SEQ ID NO: 31, or which contains or consists of SEQ ID NO: 101; and (6) CDRL3, which contains or consists of SEQ ID NO: 37; Alternatively, the antibody may comprise: (1) CDRH1, which contains or consists of SEQ ID NO: 5; (2) CDRH2, which contains or consists of SEQ ID NO: 12; (3) CDRH3, which contains or consists of SEQ ID NO: 20; (4) CDRL1, which contains or consists of SEQ ID NO: 27; (5) CDRL2, which contains or consists of SEQ ID NO: 31; and (6) CDRL3, which comprises or is composed of SEQ ID NO: 37, or comprises or is composed of QQYX1X2TPYX3, wherein X1 is selected from W or G, X2 is selected from S, H or N, and X3 is selected from S or T; preferably, CDRL3 comprises or is composed of SEQ ID NO: 37, 102, 103, 104, 136, 137, 138, 139, 140, 141 or 142; Alternatively, the antibody may comprise: (1) CDRH1, which contains or consists of SEQ ID NO: 5; (2) CDRH2, which includes or consists of any one of SEQ ID NO: 12, 91-94, 119-125; (3) CDRH3, which includes or consists of any one of SEQ ID NO: 20, 95-97, 126-131; (4) CDRL1, which includes or consists of any one of SEQ ID NO: 27, 98-99, 132-135; (5) CDRL2, which contains or consists of SEQ ID NO: 31 or 101; (6) CDRL3, which includes or consists of any one of SEQ ID NO: 37, 102-104, 136-142. Preferably, the antibody comprises or is composed of CDRs as shown in Table I and / or Table J, such as CDRH1, CDRH2, CDRH3 in Table I and CDRL1, CDRL2, CDRL3 in Table J or composed of them. Preferably, the antibody comprises or consists of CDRs as shown in Table G. Preferably, the antibody comprises or is composed of CDRs as shown in Table L. Furthermore, this disclosure further discloses an isolated anti-CLDN6 antibody or its antigen-binding moiety, wherein the antibody or its antigen-binding moiety comprises a heavy chain variable region and a light chain variable region. The heavy chain variable region comprises any amino acid sequence of SEQ ID NO: 105-111 or a sequence thereof, or any amino acid sequence of SEQ ID NO: 105-111 having at least 80%, for example, at least 82%, 85%, 88%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% sequence identity with the sequence of SEQ ID NO: 105-111; the light chain variable region comprises any amino acid sequence of SEQ ID NO: 69 or a sequence thereof, or any amino acid sequence of SEQ ID NO: 69 having at least 80%, for example, at least 82%, 85%, 88%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% sequence identity with the sequence of SEQ ID NO: 69; or The heavy chain variable region comprises a sequence of SEQ ID NO: 52 or thereof, or any amino acid sequence or a sequence comprising thereof that has at least 80% sequence identity with the sequence of SEQ ID NO: 52, for example, at least 82%, 85%, 88%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% sequence identity; the light chain variable region comprises any amino acid sequence of SEQ ID NO: 112-118 or a sequence comprising thereof, or any amino acid sequence or a sequence comprising thereof that has at least 80% sequence identity with the sequence of SEQ ID NO: 112-118, for example, at least 82%, 85%, 88%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% sequence identity. As described above, the term "conservative substitution / replacement" as used herein refers to an amino acid substitution / replacement that does not adversely affect or alter the fundamental properties of a protein / peptide containing an amino acid sequence. For example, conservative substitution / replacement can be introduced using standard techniques known in the art (e.g., site-directed mutagenesis, PCR-mediated mutagenesis, etc.). Conservative amino acid substitution includes substitution in which an amino acid residue is replaced by another amino acid residue having a similar side chain, such as substitution of physically or functionally similar residues (e.g., having similar size, shape, charge, chemical properties including the ability to form covalent or hydrogen bonds, etc.) to the corresponding amino acid residue. Families of amino acid residues with similar side chains have been defined in the art. These families include amino acids with basic side chains (e.g., lysine, arginine, and histidine), amino acids with acidic side chains (e.g., aspartic acid and glutamic acid), amino acids with uncharged polar side chains (e.g., glycine, asparagine, glutamine, serine, threonine, tyrosine, cysteine, and tryptophan), amino acids with nonpolar side chains (e.g., alanine, valine, leucine, isoleucine, proline, phenylalanine, and methionine), amino acids with β-branched side chains (e.g., threonine, valine, and isoleucine), and amino acids with aromatic side chains (e.g., tyrosine, phenylalanine, and tryptophan). Therefore, the corresponding amino acid residue is preferably substituted by another amino acid residue from the same side chain family. Methods for identifying conserved substitutions of amino acids are well known in the art (see, for example, Brummell et al., Biochem. 32: 1180-1187 (1993); Kobayashi et al., Protein Eng. 12(10): 879-884 (1999); and Burks et al., Proc. Natl. Acad. Sci. USA 94: 412-417 (1997), which are incorporated herein by reference). According to this disclosure, when referring to a specific antibody heavy chain and / or a specific antibody light chain (e.g., a chain containing a specific CDR sequence), the two heavy chains and / or the two light chains of the antibody are preferably composed of the specific antibody heavy chain and / or the specific antibody light chain, respectively. In some embodiments, the antibody or its antigen-binding portion has one or more of the following properties: (a) Combine human or monkey CLDN6 with EC50 at 5 μg / mL or less; (b) Cross-reactivity: The binding affinity to human CLDN3 and / or human CLDN4 and / or human CLDN9 is less than that to human CLDN6; (c) Kill and / or inhibit cells expressing human CLDN6 (e.g., tumor cells, such as tumor cells expressing CLDN6). The unique feature of this disclosed antibody is its ability to bind to dimin 6 on the cell surface. This has been demonstrated by flow cytometry analysis of cells expressing dimin 6. Regardless of how the antibody is produced, methods for testing the ability of an antibody to bind to the CLDN6 epitope are known in the art and include any antibody-antigen binding assay, such as radioimmunoassay (RIA), ELISA, Western blotting, immunoprecipitation, SPR, and competitive inhibition assays (see, for example, Janeway et al., below and U.S. Patent Application Publication No. 2002 / 0197266 and the above sections concerning competitive assays). According to this disclosure, in a standard assay (e.g., the assay described in this disclosure), if the antibody has a significant affinity for a predetermined target (e.g., the CLDN6 protein or cells expressing CLDN6), then the antibody is capable of binding to the predetermined target. Flow cytometry can be used to test the binding of a monoclonal antibody to live cells expressing the CLDN6 protein. Preferably, in a flow cytometry analysis (FACS) assay, the binding of the antibody to a target expressed on the cell surface is measured. If the antibody detectably binds to the target (CLDN6 protein or cells expressing CLDN6), then the antibody is capable of binding to the target and has "affinity". Preferably, if the antibody of this disclosure is present at a concentration of 10 μg / mL or less, 5 μg / mL or less, 3 μg / mL or less, 2 μg / mL or less, 1 μg / mL or less, or 0.5 μg / mL or less, the antibody detectably binds to the target. In some embodiments, the binding properties of the antibody or its antigen-binding portion may be: 5 × 10 -8 M or lower KD combined with human or monkey CLDN6; with 1×10 -9 M or lower KD combined with human or monkey CLDN6; with 5×10 -9 M or lower KD combined with human or monkey CLDN6; or with 1×10 -10 M or lower KD combined with human or monkey CLDN6. In some embodiments, the EC50 binding property of the antibody or its antigen-binding moiety may be: binding to human CLDN6 or monkey CLDN6 with an EC50 of 5 μg / mL or less; binding to human CLDN6 or monkey CLDN6 with an EC50 of 3 μg / mL or less; binding to human CLDN6 or monkey CLDN6 with an EC50 of 2 μg / mL or less; binding to human CLDN6 or monkey CLDN6 with an EC50 of 1 μg / mL or less; binding to human CLDN6 or monkey CLDN6 with an EC50 of 0.5 μg / mL or less; binding to human CLDN6 or monkey CLDN6 with an EC50 of 0.3 μg / mL or less; or binding to human CLDN6 or monkey CLDN6 with an EC50 of 0.1 μg / mL or less. In standard assays, if an antibody does not have significant affinity for the target and does not bind significantly to the target, then the antibody cannot / substantially cannot bind to the target. Preferably, in flow cytometry (FACS) analysis, where the binding of the antibody to the target (e.g., CLDN6 protein) expressed on the cell surface is measured, if the antibody does not detectably bind to the target, then the antibody (substantially) cannot bind to the target. Preferably, the antibody of this disclosure is present at concentrations up to 1 μg / mL, up to 2 μg / mL, preferably up to 5 μg / mL, preferably up to 10 μg / mL, preferably up to 20 μg / mL, more preferably up to 50 μg / mL, especially up to 100 μg / mL or up to 150 μg / mL, up to 200 μg / mL or higher, and does not detectably bind to the target (CLDN protein). An antibody is specific to a predetermined target if it can bind to it but not to other targets (i.e., it has no significant affinity for other targets or does not bind significantly to other targets in a standard assay). According to this disclosure, an antibody is CLDN6 specific if it can bind to CLDN6 but not to or significantly to other targets (especially dense proteins other than CLDN6, such as CLDN9, CLDN4, and CLDN3). The CLDN6 specificity described in this disclosure refers to the ability to bind to one or more CLDN6 epitopes, especially those in their natural conformation, and particularly human CLDN6 specificity refers to the ability to bind to one or more human CLDN6 epitopes, especially those in their natural conformation. In some embodiments, the (b) cross-reactivity of the antibody or its antigen-binding portion may be: the antibody or its antigen-binding portion does not bind to or substantially does not bind to other CLDN proteins besides CLDN6; and / or the antibody or its antigen-binding portion does not bind to or substantially does not bind to CLDN3 protein; and / or the antibody or its antigen-binding portion does not bind to or substantially does not bind to CLDN9 protein; and / or the antibody or its antigen-binding portion does not bind to or substantially does not bind to CLDN4 protein. Furthermore, TCGA data showed that CLDN9 was expressed at low levels in the pancreas (4.23 TPM, n=4) and kidneys (1.99 TPM, n=25), and was almost unexpressed in other normal tissues (the highest expression level was 0.82 TPM in the bile ducts, n=9). Meanwhile, CLDN9 expression was upregulated in ovarian cancer (5.68 TPM, n=426) and bile duct cancer (8.44 TPM, n=36). Therefore, antibodies that bind to both CLDN6 and CLDN9 can enhance their binding / inhibitory effect on tumor cells without causing significant toxic side effects. In some embodiments, the antibody or its antigen-binding moiety has strong CLDN6 binding properties (e.g., satisfying the binding properties in (a)) and some CLDN9 binding properties (e.g., the CLDN9 binding properties are 1 / 10 or less, 1 / 50 or less, 1 / 100 or less, 1 / 120 or less, 1 / 150 or less, 1 / 200 or less, or 1 / 250 or less). Antibodies or their antigen-binding moiety with such binding properties can make them more effective against tumors that broadly express CLDN6 and CLDN9, such as chimeric antibodies 58G3C7, 47D5D6, 51C10H4, 20A3-2A7, 54B5A7 and their modified or humanized antibodies. In some embodiments, the (b) cross-reactivity of the antibody or its antigen-binding portion may be: the antibody or its antigen-binding portion does not bind to or substantially does not bind to the CLDN3 protein; and / or the antibody or its antigen-binding portion binds to the CLDN9 protein (e.g., the binding characteristic to CLDN9 is 1 / 10 or less, 1 / 50 or less, 1 / 100 or less, 1 / 120 or less, 1 / 150 or less, 1 / 200 or less, 1 / 250 or less, compared to the binding characteristic to CLDN6); and / or the antibody or its antigen-binding portion does not bind to or substantially does not bind to the CLDN4 protein. In some embodiments, the (b) cross-reactivity of the antibody or its antigen-binding portion may be: the antibody or its antigen-binding portion does not bind to or substantially does not bind to the CLDN3 protein; and the antibody or its antigen-binding portion binds to the CLDN9 protein (e.g., the binding characteristic to CLDN9 is 1 / 10 or less, 1 / 50 or less, 1 / 100 or less, 1 / 120 or less, 1 / 150 or less, 1 / 200 or less, or 1 / 250 or less). Antibodies or their antigen-binding portions with such binding characteristics can exhibit superior efficacy against tumors that extensively express CLDN6 and CLDN9, while avoiding cross-reactivity in tissues that extensively express CLDN3 and reducing toxic side effects. Examples include chimeric antibodies 47D5D6, 51C10H4, 20A3-2A7, 54B5A7, and their modified or humanized antibodies. In some embodiments, the (b) cross-reactivity of the antibody or its antigen-binding portion may be: the antibody or its antigen-binding portion does not bind to or substantially does not bind to the CLDN4 protein; and the antibody or its antigen-binding portion binds to the CLDN9 protein (e.g., the binding characteristic to CLDN9 is 1 / 10 or less, 1 / 50 or less, 1 / 100 or less, 1 / 120 or less, 1 / 150 or less, 1 / 200 or less, or 1 / 250 or less). Antibodies or their antigen-binding portions with such binding characteristics can exhibit superior efficacy against tumors that extensively express CLDN6 and CLDN9, while avoiding cross-reactivity in tissues that extensively express CLDN4 and reducing toxic side effects, such as chimeric antibodies 51C10H4, 54B5A7, and their modified or humanized antibodies. In some embodiments, the (b) cross-reactivity of the antibody or its antigen-binding portion may be: the antibody or its antigen-binding portion does not bind to or substantially does not bind to CLDN4 protein; and the antibody or its antigen-binding portion does not bind to or substantially does not bind to CLDN3 protein; and the antibody or its antigen-binding portion binds to CLDN9 protein (e.g., the binding characteristic to CLDN9 is 1 / 10 or less, 1 / 50 or less, 1 / 100 or less, 1 / 120 or less, 1 / 150 or less, 1 / 200 or less, 1 / 250 or less). Antibodies or their antigen-binding portions with such binding characteristics can exhibit superior efficacy against tumors that widely express CLDN6 and CLDN9, while avoiding cross-reactivity in tissues that widely express CLDN4 and CLDN3, and avoiding / reducing toxic side effects, such as with chimeric antibodies 51C10H4, 54B5A7 and their modified antibodies or humanized antibodies, thereby maximizing therapeutic efficacy and minimizing systemic toxicity. FACS analysis revealed that the antibodies disclosed herein, particularly those with the aforementioned characteristics, exhibit strong C6 reactivity (selective binding to the surface of cells expressing CLDN6) and lower cross-reactivity. Although the antibodies disclosed herein have significant CLDN6-specific binding properties, the cross-reactivity of some antibodies with CLDN3 and CLDN4 unexpectedly gives some antibodies a stronger and broader tumor cell killing effect. For example, studies have shown that the expression levels of CLDN3 and CLDN4 in several ovarian cancer cases are 83-109 times higher than in normal epithelial cells. Furthermore, DNA microarray analysis revealed that CLDN3 and CLDN4 are two of the five genes with the highest differential expression in ovarian cancer, and their expression levels are abnormally elevated in many ovarian cancer cases. Therefore, antibodies targeting CLDN3 / 4 or both have the potential as therapeutic agents. Some antibodies have also been shown to have anti-tumor effects in preclinical animal models, and some have even entered the clinical trial stage. For instance, in existing technologies, a company has screened and humanized mouse anti-KM3900, which can recognize and bind to the second extracellular loop of CLDN4. In in vitro experiments, this antibody, KM3934, exhibited antibody-dependent cytotoxicity (ADCC) and complement-dependent cytotoxicity (CDC), and significantly inhibited tumor growth in immunodeficient mice transplanted with human ovarian cancer cell line MCAS or human pancreatic cancer cell line CFPAC-1. In some embodiments, the antibody or its antigen-binding portion has strong CLDN6 binding properties (e.g., satisfying the binding properties of (a)) and certain CLDN4 binding properties (e.g., the CLDN4 binding properties are 1 / 4 or less, 1 / 10 or less, 1 / 50 or less, 1 / 100 or less, 1 / 120 or less, 1 / 150 or less, 1 / 200 or less, 1 / 250 or less). Such binding properties of the antibody or its antigen-binding portion can make it more effective against tumors or tissues that widely express CLDN6 and CLDN4, such as more prominent inhibitory or killing effects in ovarian cancer cells, for example, chimeric antibodies 20A3-2A7, 47D5D6, 58G3C7, 15H2D4 and their modified antibodies or humanized antibodies. In some embodiments, the antibody or its antigen-binding portion has a strong CLDN6 binding property (e.g., satisfying the binding property of (a)) and a certain CLDN3 binding property (e.g., the CLDN3 binding property is 1 / 20 or less, 1 / 50 or less, 1 / 100 or less, 1 / 120 or less, 1 / 150 or less, 1 / 200 or less, 1 / 250 or less). Such binding properties of the antibody or its antigen-binding portion can make it more effective against tumors or tissues that widely express CLDN6 and CLDN3, such as more prominent inhibitory or killing effects in ovarian cancer cells, for example, chimeric antibodies 47A5B10, 58G3C7 and their modified antibodies or humanized antibodies. In some embodiments, the antibody or its antigen-binding moiety has strong CLDN6 binding properties (e.g., satisfying the binding properties in (a)) and some CLDN3 binding properties (e.g., the CLDN3 binding properties are 1 / 20 or less, 1 / 50 or less, 1 / 100 or less, 1 / 120 or less, 1 / 150 or less, 1 / 200 or less, 1 / 250 or less) and some CLDN4 binding properties (e.g., the CLDN4 binding properties are the same as the CLDN6 binding properties). (1 / 4 or less, 1 / 10 or less, 1 / 50 or less, 1 / 100 or less, 1 / 120 or less, 1 / 150 or less, 1 / 200 or less, 1 / 250 or less), antibodies or their antigen-binding portions with such binding properties can have more outstanding effects against tumors or tissues that widely express CLDN6, as well as CLDN3 and CLDN4, such as having more outstanding inhibitory or killing effects on ovarian cancer cells, such as chimeric antibodies 47A5B10, 58G3C7 and their modified antibodies or humanized antibodies. In some embodiments of this disclosure, the antibody or its antigen-binding portion having (c) killing and / or inhibiting cells expressing human CLDN6 (e.g., tumor cells, such as tumor cells expressing CLDN6) can be: inducing the killing and / or inhibition of cells expressing human CLDN6 (e.g., tumor cells, such as tumor cells expressing CLDN6) through antibody-dependent cell-mediated cytotoxicity (ADCC); and / or inducing the killing of cells expressing human CLDN6 (e.g., tumor cells, such as tumor cells expressing CLDN6) through complement-dependent cytotoxicity (CDC). On one hand, this disclosure provides an isolated anti-CLDN6 antibody or its antigen-binding portion thereof, wherein the isolated antibody or its antigen-binding portion thereof competitively binds to CLDN6 expressed on the cell surface in conjunction with the antibody or its antigen-binding portion as described above. On one hand, this disclosure provides an isolated anti-CLDN6 antibody or its antigen-binding portion thereof, wherein the isolated antibody or its antigen-binding portion comprises a complementary determining region sequence in any sequence shown in SEQ ID NO: 41-46, 48-60, 79-83 or any sequence composed thereof, and a complementary determining region sequence comprising any sequence shown in SEQ ID NO: 61-66, 68-73 or any sequence composed thereof. In some implementations, the antibody is a monoclonal antibody. In some embodiments, the antibody is a chimeric antibody, a humanized antibody, or a modified antibody, such as a modified chimeric antibody. In some embodiments, the isolated antibody or its antigen-binding portion comprises a constant region of IgG. The constant region of IgG is preferably selected from the constant regions of IgG1, IgG2, IgG3, or IgG4. More preferably, the constant region of IgG is selected from the constant region of IgG1. In some embodiments, the isolated antibody or its antigen-binding portion comprises or consists of a heavy chain composed of any sequence selected from the group consisting of: a polypeptide having at least 80%, 82%, 85%, 88%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% sequence identity with SEQ ID NO: 143-167, SEQ ID NO: 87, or SEQ ID NO: 89; and a light chain comprising or consists of any sequence selected from the group consisting of: a polypeptide having at least 80%, 82%, 85%, 88%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% sequence identity with SEQ ID NO: 168-178, SEQ ID NO: 88, or SEQ ID NO: 90. The results demonstrated that, although the antibodies disclosed herein, such as 51C10H4 (composed of the heavy chain of SEQ ID NO: 87 and the light chain of SEQ ID NO: 88) and 54B5A7 (composed of the heavy chain of SEQ ID NO: 95 and the light chain of SEQ ID NO: 172), are excellent in terms of their properties regarding binding to CLDN6 and their efficacy in tumor treatment, respectively, we have recombined existing and validated antibodies (e.g., the heavy chain, light chain, or CDR region of the antibody) to maintain their desired properties. For example, by recombining the heavy and light chains of antibodies 51C10H4 and 54B5A7, a new improved chimeric monoclonal antibody, RecA101, was generated. This improved chimeric monoclonal antibody, RecA101 (composed of the heavy chain of SEQ ID NO: 87 and the light chain of SEQ ID NO: 172), has also demonstrated excellent properties regarding binding to CLDN6 and its efficacy in tumor treatment. In the art, there are various methods for modifying antibodies without altering their desired properties. In addition to the recombination methods described above, constructing antibodies by replacing amino acids has also been shown to be a feasible approach in this disclosure. For example, replacing the methionine at position 5 of the light chain CDR3 of antibody 51C10H4 with amino acid N, replacing V at position 2 of the heavy chain CDR2 with I and S at position 10 with N, and replacing L at position 10 of the heavy chain CDR3 with M, results in antibodies named 54B5A7 in this disclosure. These antibodies have been shown to possess the desired properties, including excellent binding properties to CLDN6 and efficacy in tumor therapy. For example, in this disclosure, the sequences, including chimeric antibody sequences or humanized antibody sequences, undergo conserved amino acid substitutions. For instance, when the CDR region of the sequence in this disclosure contains a deamidation hotspot NG (such as the CDR2 region of 20A3-2A7, the CDR2 region of 51C10H4, or the CDR2 region of PiH1001-PiH1008), this site is mutated in various ways. The mutation schemes are diverse; for example, G in NG can be mutated to A / S / D / Q. Alternatively, N in NG can be mutated to S / Q / A to remove amino acids that pose a risk of deamidation. For example, when the CDR region of the sequence in this disclosure contains DG (such as the CDR3 region of 51C10H4, the CDR3 region of PiH1001-PiH1008), this site can be mutated in various ways. The mutation schemes are diverse; for example, D in DG can be mutated to E / S / G, or G can be mutated to A / S / D / Q, to reduce the risk of reduced antigen binding affinity caused by isomerization. Conserved amino acid substitutions can be made to the sequences in this invention, including chimeric antibody sequences or humanized antibody sequences. For example, when the CDR region of the sequence in this invention contains V (such as the CDR2 region of PiH1004), this site can be mutated in various ways. The mutation schemes are diverse; for example, V can be mutated to A / I / L. In some embodiments, the antibody is selected from PiH1001, PiH1002, PiH1003, PiH1004, PiH1005, PiH1006, PiH1007, PiH1008, PiH2001, PiH2004, PiH2005, PiH2006, PiH2007, PiH2008, PiH2009, PiH2010, PiH2011, PiH2012, and PiH2012-1. In some embodiments, the antibody is selected from PiH1001-M1, PiH1001-M2, PiH1001-M3, PiH1001-M4, PiH1002-M1, PiH1002-M2, PiH1002-M3, PiH1002-M4, PiH1003-M1, PiH1003-M2, PiH1003-M3, PiH1003-M4, PiH1004-M1, PiH1004-M2, PiH1004-M3, PiH1 004-M4, PiH1005-M1, PiH1005-M2, PiH1005-M3, PiH1005-M4, PiH1006-M1, PiH1006-M2, PiH1006-M3, PiH1006- M4, PiH1007-M1, PiH1007-M2, PiH1007-M3, PiH1007-M4, Pi111008-M1, PiH1008-M2, PiH1008-M3, PiH1008-M4. Antibodies primarily interact with target antigens through amino acid residues located in the complementarity-determining regions (CDRs) of the six heavy and light chains. For this reason, the amino acid sequences within the CDRs are more diverse than those outside the CDRs among antibodies. Since the CDR sequence is responsible for most antibody-antigen interactions, it is possible to express recombinant antibodies mimicking the properties of a specific naturally occurring antibody by constructing expression vectors containing the CDR sequence from that specific naturally occurring antibody, which are then grafted onto frame sequences from different antibodies with different properties (see, for example, Riechmann, L et al. (1998) Nature 332:323-327; Jones, P. et al. (1986) Nature 321:522-525; and Queen, C. et al. (1989) Proc. Natl. Acad. Sci. USA 86:10029-10033). Such frame sequences are available from public DNA databases that include germline antibody gene sequences. These germline sequences differ from mature antibody gene sequences because they do not contain fully assembled variable genes, which are formed during B cell maturation via V(D)J linkages. Germline gene sequences will also have sequences that differ from those of the high-affinity secondary repertoire antibody at individual locations that uniformly traverse the variable region. Mouse antibodies exhibit high immunogenicity in humans, leading to decreased therapeutic efficacy with repeated administration. The primary immunogenicity is mediated by the heavy chain constant region. However, the immunogenicity of mouse antibodies in humans can be reduced or completely avoided by chimeric or humanized versions of the antibodies. Chimeric antibodies are antibodies whose different parts originate from different animal species; for example, antibodies having a variable region derived from a mouse antibody and a constant region derived from a human immunoglobulin. Chimeric antibodies are obtained by linking the variable regions of the mouse antibody heavy and light chains to the constant regions of the human heavy and light chains (e.g., as described by Kraus et al., in Methods in Molecular Biology series, Recombinant antibodies for cancer therapy ISBN-0-89603-918-8). In a preferred embodiment, chimeric antibodies are generated by linking the constant region of the human K light chain to the variable region of the mouse light chain. In another preferred embodiment, chimeric antibodies are generated by linking the constant region of the human λ light chain to the variable region of the mouse light chain. Humanized antibodies are antibodies that have had their CDR sequences / antigen-binding portions or sites derived from another mammalian species, such as mice, transplanted onto a human framework sequence. To reduce the immunogenicity of the antibody to humans, a humanized anti-CLDN6 antibody is produced using the sequence of the anti-CLDN6 antibody disclosed herein. The CDR region of a mouse-derived anti-CLDN6 antibody is combined with a human-derived framework region (e.g., human immunoglobulin) to form the humanized anti-CLDN6 antibody of this disclosure. The humanized antibody is expected to retain the function of binding to human CLDN6 as well as the function of binding to monkey CLDN6. After humanization of the disclosed antibodies (including antibodies with conserved amino acid substitutions), and following screening, at least 18 humanized antibody sequences with the desired properties were obtained (composed of the heavy chain of any sequence in SEQ ID NO: 97-108 and SEQ ID NO: 97-108). NO: any light chain from sequence 122-126), specifically, PiH1001, PiH1002, PiH1003, PiH1004, PiH1005, PiH1006, PiH1007, and PiH1008 are humanized antibodies that meet the requirements after humanization of the chimeric antibody 51C10H4. Their CDR regions are the same as those of 51C10H4. Among them, PiH1001, PiH1002, PiH1003, and PiH1004 are derived from the same light chain L3 and different heavy chains H1-H4. Among them, humanized antibodies PiH1005, PiH1006, PiH1007, and PiH1008 are derived from the same light chain L4 and different heavy chains H1-H4. Specifically, PiH2001, PiH2004, PiH2005, PiH2006, PiH2007, PiH2008, PiH2009, PiH2010, PiH2011, and PiH2012 are humanized antibodies obtained by humanizing the chimeric antibody 54B5A7. Their CDR regions are identical to those of 54B5A7. Among them, PiH2001 and PiH2004 are derived from the same... Combinations of a light chain L3' and different heavy chains H1' and H4', wherein PiH2005, PiH2006, PiH2007, and PiH2008 are combinations derived from the same light chain L4' and H1', ​​H2', H3', and H4' including the aforementioned different heavy chains; wherein PiH2009, PiH2010, PiH2011, and PiH2012 are combinations derived from the same light chain L5 and different heavy chains H5, H6, H7, and H8. Results demonstrate that, compared to the corresponding chimeric antibodies prior to humanization, the humanized antibodies described in this disclosure, while exhibiting some reductions in binding properties to human CLDN6 and / or monkey CLDN6 proteins, still demonstrate excellent or conforming binding properties (e.g., KD binding or EC50 binding), tumor cell binding, ADCC effect, CDC effect, and endocytosis effect, as required by the CLDN6 antibodies described in this disclosure. Antibody preparation or production The antibodies of this disclosure can be generated using various techniques, including conventional monoclonal antibody methods, such as the standard somatic cell hybridization technique described in Kohler and Milstein, Nature 256:495 (1975). While hybridoma techniques are preferred, other techniques for generating monoclonal antibodies can be used in principle, such as viral or oncogene transformation of B lymphocytes or phage display using antibody gene libraries, somatic cell hybridization, and, for example, genetic engineering recombination techniques. For instance, DNA molecules encoding the heavy and light chain genes of the antibodies of this disclosure can be obtained through chemical synthesis or PCR amplification, the resulting DNA molecules can be inserted into an expression vector, transfected into host cells, and then cultured under specific conditions to express the antibodies of this disclosure. Other preferred animal systems for preparing hybridomas that secrete monoclonal antibodies are the rat and rabbit systems (e.g., described in Spieker-Polet et al., Proc. Natl. Acad. Sci. USA 92: 9348 (1995), see also Rossietal. Am. J. Clin. Pathol. 124: 295 (2005)). Hybridoma production in mice is a well-established method. Immunization protocols and techniques for isolating immunized spleen cells for fusion are known in the art. Fusion partners (e.g., mouse myeloma cells) and fusion methods are also known. Monoclonal antibodies can be prepared using a variety of techniques known in the art, including hybridoma techniques, recombinant techniques, phage display techniques, transgenic animals, or combinations thereof. For example, monoclonal antibodies can be produced using hybridomas and well-established biochemical and genetic engineering techniques, as described in detail in An, Zhiqiang (ed.) Therapeutic Monoclonal Antibodies: From Bench to Clinic, John Wiley and Sons, 1st ed. 2009; Shire et al. (eds.) Current Trends in Monoclonal Antibody Development and Manufacturing, Springer Science+Business Media LLC, 1st ed. 2010; Harlow et al., Antibodies: A Laboratory Manual, Cold Spring Harbor Laboratory Press, 2nd ed. 1988; Hammerling et al., in: Monoclonal Antibodies and T-Cell Hybridomas 563-681 (Elsevier, NY, 1981), each of which is incorporated herein by reference in its entirety. It should be understood that the selected binding sequence can be further modified, for example, to increase affinity for the target, humanize the target binding sequence, improve its production in cell cultures, reduce its immunogenicity in vivo, generate multispecific antibodies, etc., and antibodies containing modified target binding sequences are also antibodies of this disclosure. In a preferred embodiment, an anti-CLDN6 monoclonal antibody is prepared by using a hybridoma. To obtain hybridomas that produce antibodies of this disclosure, such as the human monoclonal antibodies of this disclosure, spleen cells and / or lymph node cells from immunized mice can be isolated and fused into a suitable immortalized cell line, such as a mouse myeloma cell line. The resulting hybridomas are screened for the production of antigen-specific antibodies. The generation of hybridomas is well known in the art. See, for example, Harlow and Lane (1988), Antibodies, A Laboratory Manual, Cold Spring Harbor Publications, New York. The antibodies disclosed herein can also be generated in host cells transfected with tumors using, for example, a combination of recombinant DNA techniques and gene transfection methods well known in the art (e.g., Morrison, S. (1985) Science 229:1202). In some embodiments, DNA encoding a partial or full-length light and heavy chain, obtained by standard molecular biology techniques, is inserted into one or more expression vectors such that the gene is operatively linked to transcriptional and translational regulatory sequences. In this context, the term "operatively linked" is intended to mean linking the antibody gene to a vector such that the transcriptional and translational control sequences within the vector perform their intended functions of regulating the transcription and translation of the antibody gene. Antibody light chain genes and antibody heavy chain genes can be inserted into the same or different expression vectors. In some embodiments, the variable region is used to generate a full-length antibody gene of any antibody isotype by inserting it into an expression vector that already encodes the heavy chain constant region and light chain constant region of the desired isotype, such that the VH segment is operatively linked to the CH segment within the vector and the VL segment is operatively linked to the CL segment within the vector. Alternatively or additionally, the recombinant expression vector can encode a signal peptide that promotes the secretion of the antibody chain from the host cell. The antibody chain gene can be cloned into the vector such that the signal peptide is linked to the N-terminus of the antibody chain gene. The signal peptide can be an immunoglobulin signal peptide or a heterologous signal peptide (i.e., a signal peptide derived from a non-immunoglobulin protein). To express the light and heavy chains, expression vectors encoding the heavy and light chains are transfected into host cells using standard techniques. Various forms of the term "transfection" are intended to encompass a wide range of techniques commonly used to introduce exogenous DNA into prokaryotic or eukaryotic host cells, such as electroporation, calcium phosphate precipitation, DEAE-glucan transfection, etc. Antibodies disclosed herein can be expressed in prokaryotic or eukaryotic host cells, such as mammalian host cells (which can assemble and secrete antibodies with appropriate folding and immunological activity). Mammalian host cells used for expressing the recombinant antibodies of this disclosure include Chinese hamster ovary cells (CHO cells) (including dhfr CHO cells described in Urlaub and Chasin, (1980) Proc. Natl. Acad. Sci. USA 77: 4216-4220) used with DHFR selection markers (e.g., as described in RJ Kaufman and PA Sharp (1982) J. MoI. Biol. 159: 601-621), NSO myeloma cells, COS cells, and SP2 cells. In particular, for use with NSO myeloma, another expression system is the GS gene expression system disclosed in WO 87 / 04462, WO 89 / 01036, and EP 338,841. When the recombinant expression vector encoding the antibody gene is introduced into mammalian host cells, the antibody is produced by culturing the host cells for a period sufficient to allow antibody expression in the host cells or by secreting the antibody into the culture medium in which the host cells grow. The antibody can be recovered from the culture medium using standard protein purification methods. In another preferred embodiment, transgenic or transchromatic mice with a partial human immune system (rather than a mouse system) can be used to generate human monoclonal antibodies against CLDN6. Another strategy for generating monoclonal antibodies is to directly isolate the antibody-encoding gene from the antibody-producing lymphocytes of a defined strategy, for example, see Babcock et al., 1996; A novel strategy for generating monoclonal antibodies from single, isolated lymphocytes producing antibodies of a defined strategy. For details on recombinant antibody engineering, see also Welschof and Krau, Recombinant antibodies for cancer therapy ISBN-0-89603-918-8 and Benny KCLo Antibody Engineering ISBN 1-58829-092-1. To prepare chimeric antibodies, the variable region of mouse immunoglobulin can be ligated to the constant region of human immunoglobulin using methods known in the art (see, for example, US Patent 4,816,567, Cabilly et al.). The isolated nucleic acid encoding the VH region can be converted into a full-length heavy chain gene by operably ligating the nucleic acid encoding VH to another DNA molecule encoding the heavy chain constant region (CH1, CH2, and CH3). The sequence of the human heavy chain constant region gene is known in the art (see, for example, Kabat et al. (1991), Sequences Of Proteins of Immunological Interest, Fifth Edition, USDapartment of Health and Human Services, NIH Publication No. 91-3242). The heavy chain constant region can be an IgG1, IgG2, IgG3, IgG4, IgA, IgE, IgM, or IgD constant region, but more preferably an IgG1 or IgG4 constant region. By operatively linking DNA encoding the VL region to another DNA molecule encoding the light chain constant region CL, isolated nucleic acids encoding the VL region can be converted into a full-length light chain gene (and a Fab light chain gene). The sequences of human light chain constant region genes are known in the art (see, for example, Kabat et al., ibid.), and DNA fragments containing these regions can be obtained by standard PCR amplification. In a preferred embodiment, the light chain constant region can be a K or λ constant region, but is generally preferred to be a K constant region. Once the DNA fragments encoding the VH and VL regions are obtained, these DNA fragments can be further manipulated using standard recombinant DNA techniques, such as converting the variable region gene into a full-length antibody chain gene, a Fab fragment gene, or an scFv gene. In these manipulations, the DNA fragment encoding VL or VH is operatively linked to another DNA fragment encoding a different protein, such as an antibody constant region or a flexible linker. The term "operatively linked" as used herein is intended to mean that two DNA fragments are linked such that the amino acid sequences encoded by both DNA fragments remain within the frame. To prepare humanized antibodies, mouse CDR regions can be inserted into human framework sequences using methods known in the art (see Winter's US 5,225,539; Queen et al.'s US 5,530,101; US ​​5,585,089; US 5,693,762; and Lo, Benny, KC, editor, in Antibody Engineering: Methods and Protocols, volume 248, Humana Press, New Jersey, 2004). Alternatively, transgenic animals that do not produce endogenous immunoglobulins after immunization and can generate a complete human antibody library can be used. For example, it has been reported that homozygous deletion of the antibody heavy chain linker (JH) gene in chimeric and germline mutant mice can completely suppress the production of endogenous antibodies, and then transfer of human germline immunoglobulin gene arrays into said germline mutant mice will cause the mice to produce human antibodies upon encountering antigen stimulation (see, for example, Jakobovits et al., 1993, Proc. Natl. Acad. Sci. USA 90: 2551; Jakobovits et al., 1993, Nature 362: 255-258; Bruggermann et al., 1993, Year in Immunology 7: 33; and Duchosal et al., 1992, Nature 355: 258). Non-limiting examples of the aforementioned transgenic animals include HuMAb mice (Medarex, Inc.) containing miniloci of human immunoglobulin genes encoding unrearranged human heavy chain (μ and γ) and K light chain immunoglobulin sequences, coupled with targeted mutations that inactivate endogenous μ and κ chain loci (see, for example, Lonberg et al. (1994) Nature 368(6474): 856-859); or “KM mice” carrying human heavy chain transgenes and human light chain transchromosomes. TM (See patent application WO02 / 43478). Other methods for humanizing antibodies include phage display technology (Hoogenboom et al., 1991, J.Mol.Biol. 227: 381; Marks et al., J.Mol.Biol. 1991, 222: 581-597; Vaughan et al., 1996, Nature Biotech 14: 309). Nucleic acid molecules encoding the antibodies disclosed herein In some respects, this disclosure relates to isolated nucleic acid molecules comprising nucleic acid sequences encoding heavy chain variable regions and / or light chain variable regions of isolated antibodies as disclosed herein. The nucleic acids disclosed herein can be obtained using standard molecular biology techniques. For hybridoma-expressed antibodies (e.g., hybridomas prepared from transgenic mice carrying human immunoglobulin genes, as further described below), the light and heavy chains of the antibody prepared via hybridoma can be obtained by standard PCR amplification or cDNA cloning techniques. For antibodies obtained from immunoglobulin gene libraries (e.g., using phage display technology), the nucleic acid encoding such antibody can be recovered from the gene library. To prepare chimeric antibodies, the variable region of a mouse immunoglobulin can be ligated to the constant region of a human immunoglobulin using methods known in the art (see, for example, U.S. Patent No. 4,816,567 to Cabilly et al.). By operatively ligating a nucleic acid encoding VH to another DNA molecule encoding the heavy chain constant region (CH1, CH2, and CH3), isolated nucleic acids encoding the VH region can be converted into a full-length heavy chain gene, and DNA fragments containing these regions can be obtained by standard PCR amplification. By operatively ligating DNA encoding VL to another DNA molecule encoding the light chain constant region CL, isolated nucleic acids encoding the VL region can be converted into a full-length light chain gene (and a Fab light chain gene). Once DNA fragments encoding the VH and VL regions are obtained, these DNA fragments can be further manipulated using standard recombinant DNA techniques, such as converting the variable region gene into a full-length antibody chain gene, a Fab fragment gene, or an scFv gene. In these operations, the DNA fragment encoding VL or VH is operatively ligated to another DNA fragment encoding a different protein, such as an antibody constant region or a flexible linker. In some embodiments, this disclosure relates to isolated nucleic acid molecules comprising nucleic acid sequences encoding heavy chain variable regions of isolated antibodies as disclosed herein. In some embodiments, this disclosure relates to isolated nucleic acid molecules comprising nucleic acid sequences encoding a light chain variable region of an isolated antibody as disclosed herein. On the one hand, this disclosure provides a carrier that contains nucleic acid molecules as described above. On the one hand, this disclosure provides a host cell that contains the nucleic acid molecules or the vectors described above. Conjugate On one hand, this disclosure provides a conjugate comprising an antibody or its antigen-binding moiety as described above, coupled to at least one detectable label. The detectable label includes, but is not limited to: (i) providing a detectable signal; (ii) interacting with a first or second label to modify the detectable signal provided by the first or second label, such as FRET (fluorescence resonance energy transfer); (iii) influencing mobility (e.g., electrophoretic mobility) through charge, hydrophobicity, shape, or other physical parameters; or (iv) providing a trapping motif, such as affinity, antibody / antigen, or ion complexation. Suitable structures as labels include fluorescent labels, luminescent labels, chromophore labels, radioisotope labels, and isotope labels, preferably stable isotope labels and isobaric labels. Labels include: enzyme labels (e.g., horseradish peroxidase, alkaline phosphatase, β-galactosidase, urease, glucose oxidase, etc.), particulate labels (especially metal particulate labels, magnetic particulate labels, polymer particulate labels), small organic molecules (e.g., biotin, receptor ligands or binding molecules (e.g., cell adhesion proteins or lecithin), and labels containing nucleic acid and / or amino acid residues that can be detected by using a binding agent. Labels are not limited to barium sulfate, iodine... Sitac acid, iodopic acid, calcium amiodarone propionate, sodium diatrizoate, meglumine diatrizoate, meglumine methyl diatrizoate, sodium caseinate, and radiodiagnostic agents (including positron emitters (e.g., fluorine-18 and carbon-11), gamma emitters (e.g., iodine-123, iodine-125, technetium-99m, iodine-131, and indium-111), nuclear magnetic resonance nuclides (e.g., fluorine and gadolinium)), luminescent substances (e.g., isoluminol and acridinium ester), fluorescent substances (e.g., fluorescein and rhodamine), and colored substances (e.g., latex particles and colloidal gold). The detectable markers described above can be detected by methods known in the art. For example, radioactive markers can be detected using photographic film or a scintillation calculator, and fluorescent markers can be detected using a photodetector to detect emitted light. Enzyme markers are generally detected by providing a substrate to the enzyme and detecting the reaction product produced by the enzyme's action on the substrate, and calorimetric markers are detected by simple visual coloring. In some embodiments, such markers can be used for immunological assays (e.g., enzyme-linked immunosorbent assay, radioimmunoassay, fluorescence immunoassay, chemiluminescence immunoassay, etc.). In some embodiments, the detectable markers described above can be linked to the antibodies or antigen-binding fragments of this disclosure using connectors of varying lengths to reduce potential steric hindrance. Antibody drug conjugates On one hand, this disclosure provides an antibody-drug conjugate comprising one or more drug portions / therapeutic agents, said drug portions being directly or via a linker (e.g., covalently linked) to the antibody or its antigen-binding portion as described above. Because antibody-drug conjugates have the ability to selectively deliver one or more drugs to target tissues (e.g., tumor-associated antigens, such as tumors expressing CLDN6 and / or CLDN9), antibody-drug conjugates can enhance the therapeutic efficacy of the antibodies or their antigen-binding portions disclosed herein in treating diseases (e.g., cancer). In a specific implementation, this disclosure provides an antibody-drug conjugate comprising: An anti-CLDN6 antibody or its antigen-binding moiety, wherein the anti-CLDN6 antibody is preferably as described above, and One or more pharmaceutical portions, said pharmaceutical portions being directly or via a linker (preferably covalently linked) to the anti-CLDN6 antibody or its antigen-binding portion, wherein The drug is selected from cytotoxic agents, cell inhibitors, chemotherapeutic agents, radiotherapy agents, anti-angiogenic agents, immunosuppressants, anti-metastatic agents, targeted anticancer agents, and / or other anticancer agents. In some embodiments, the drug portion can permeate the cell membrane. In some embodiments, the drug component is selected from microtubule inhibitors, DNA double-strand disruptors, topoisomerase inhibitors, DNA alkylating agents, RNA polymerase inhibitors, RNA cleavage enzyme inhibitors, Bcl-xL inhibitors, antimitotic agents, sodium-potassium ion pump ATPase inhibitors, matrix metalloproteinase inhibitors, and immune agonists. In some implementations, "cytotoxic agent" refers to any molecule (chemical or biochemical) that is toxic to cells. In some implementations, the chemotherapeutic agent is a topoisomerase inhibitor. Topoisomerases are enzymes capable of altering the topology of DNA in eukaryotic cells. They are essential for cell function and cell proliferation. Generally, two classes of topoisomerases, type I and type II, exist in eukaryotic cells. Topoisomerase I is a monomeric enzyme with a molecular weight of approximately 100,000. This enzyme binds to DNA and introduces transient single-strand breaks, causing the double helix to unwind (or allowing it to unwind), and then reseals the breaks before dissociating from the DNA strand. Various topoisomerase inhibitors have recently shown clinical efficacy in treating people with cancers such as ovarian cancer, esophageal cancer, or non-small cell lung cancer. In some implementations, the topoisomerase inhibitor is camptothecin or a camptothecin analogue. Camptothecin is a water-insoluble cytotoxic alkaloid produced by the native Chinese tree *Camptotheca accuminata* and the native Indian tree *Nothapodytes foetida*. Camptothecin exhibits tumor cell growth inhibitory activity against a variety of tumor cell types. Camptothecin analogues are typically specific inhibitors of DNA topoisomerase I. The term "topoisomerase inhibitor" refers to any tumor cell growth inhibitory compound that is structurally related to camptothecin. In some implementations, the chemotherapeutic agents include antimitotic agents that inhibit cell division by blocking tubulin polymerization, and substances that destabilize or alter microtubule dynamics, i.e., tubulin inhibitors, such as maytansine alkaloids or derivatives thereof (e.g., DM1 or DM4), or olistatin or derivatives thereof. In some embodiments, the drug portion is selected from olistatin derivatives, maytansine derivatives, and pyrrolobenzodiazepines. Dimer derivatives, camptothecin derivatives, or cazithromycin derivatives. In some implementations, the maytansine derivative is selected from maytansine DM1, maytansine DM4, etc. In some embodiments, the pharmaceutical ingredient is selected from salipodin, monomethylolpropionate E (MMAE), monomethylolpropionate F (MMAF), PF-06380101, DXd, topotecan, irinotecan, 7-ethyl-10-hydroxycamptothecin (SN38) and 9-aminocamptothecin, maytansin DM1, maytansin DM4, PDB dimer or N-acetyl-γ11 kazimidycin. In some embodiments, olistatin or its derivatives are selected from salicylate, monomethylolistatin E (MMAE), monomethylolistatin F (MMAF), or PF-06380101. MMAE is an olistatin derivative, also known as monomethyl olistatin E, with the following structural formula: Specifically, the term "MMAE" refers to the compound (S)-N-((3R,4S,5S)-1-((S)2-((1R,2R)-3(((1S,2R)-1-hydroxy-1-phenylpropan-2-yl)amino)-1-methoxy-2-methyl-3-oxopropyl)pyrrolidine-1-yl)-3-methoxy-5-methyl-1-oxohepane-4-yl)-N,3-dimethyl-2-((S)-3-methyl-2-(methylamino)butamido)butamido. MMAE is actually demethylated olistatin E, meaning the N-terminal amino group has only one methyl substituent, instead of the two substituents found in olistatin E itself. In some embodiments, camptothecins or their derivatives are selected from DXd, topotecan, irinotecan, 7-ethyl-10-hydroxycamptothecin (SN38) and 9-aminocamptothecin. DXd is a camptothecin derivative and an effective derivative of ethanotecan. CAS No.: 1599440-33-1, and its structural formula is as follows: In some embodiments, the camptothecin derivative is an active metabolite of irinotecan (CPT-11). In some such embodiments, the camptothecin analog is 7-ethyl-10-hydroxycamptothecin (SN38). As a metabolite, SN38 is formed by the hydrolysis of irinotecan by a carboxylesterase. In some embodiments, SN38 has one of the following structures: Maytansine alkaloids are well known in the art and maytansine derivatives can be synthesized or isolated from natural sources using known techniques. According to this disclosure, particularly preferred maytansine alkaloids are thiol-containing derivatives of maytansine, such as DM1 and DM4. Such thiol-containing derivatives of maytansine include compounds in which a methyl group bound to a carbonyl group is replaced by a group containing a free thiol group (e.g., the group -R-SH, where R represents an alkylene or other carbon-containing atom). Mertansine DM1 is derived from maytansine, specifically referring to the compound N2'-deacetylated N2'-(3-mercapto-1-oxopropyl)-matansine, CAS No.: 139504-50-0, with the following structural formula: "DM4" refers to the compound N2'-deacetylated-N2'-(4-methyl-4-mercapto-1-oxopentyl)-matansin. Various suitable adapters are known in the art. The adapter can be cleavable (cleavable adapter), for example, under physiological conditions, such as intracellular conditions, such that cleavage of the adapter releases the drug in the intracellular environment. Alternatively, the adapter can be cleaved under extracellular conditions, such as outside tumor cells or near tumor masses, such that cleavage of the adapter releases the drug that preferentially penetrates into the tumor cells. In other embodiments, the adapter is non-cleavable (non-cleavable adapter) and releases the drug, for example, through antibody degradation. The linker can bind to chemically reactive groups on the antibody moiety, such as free amino, imino, hydroxyl, thiol, or carboxyl groups (e.g., N- or C-terminal, ε-amino group of one or more lysine residues, free carboxylic acid group of one or more glutamic or aspartic acid residues, thiol group of one or more cysteine ​​residues, or hydroxyl group of one or more serine or threonine residues). The linker binding site can be a native residue in the amino acid sequence of the antibody moiety, or the site can be introduced into the antibody moiety, for example, through DNA recombination techniques (e.g., by introducing cysteine ​​or protease cleavage sites into the amino acid sequence) or through protein biochemistry (e.g., reduction, pH regulation, or proteolysis). The linker binding site can also be a non-natural amino acid. The linker binding site can also be a glycan on the antibody. In some embodiments, the connector is a hydrophilic connector that imparts hydrophilicity to the conjugate. In some embodiments, the hydrophilic connector comprises polyethylene glycol (PEG). In some embodiments, the hydrophilic connector is a connector disclosed in U.S. Patent 7,999,083, such as CL2A. In some embodiments, the hydrophilic connector is a connector disclosed in U.S. Patents 8,080,250 and 8,759,496, such as CL2E. In some embodiments, this disclosure provides an antibody-drug conjugate, wherein the linker is a cleavable linker, preferably comprising a peptide chain portion that can be cleaved by an enzyme, such as a peptide linker that can be cleaved by intracellular or extracellular peptidases or proteases (e.g., cathepsins), said enzymes including, but not limited to, lysosomal or endosomal proteases. In some embodiments, the peptide linker is a linker of about 1 to 50 amino acids in length, or of 5 to 50, 3 to 5, 5 to 10, 5 to 15, or 10 to 30 amino acids in length. In some embodiments, the peptide linker comprises at least two, at least three, at least four, or at least five amino acids. In some embodiments, the antibody is linked to the linker via the cysteine ​​thiol group of the antibody. In some embodiments, this disclosure provides an antibody-drug conjugate, wherein the linker comprises a peptide chain selected from valine-citrulline (VC), valine-alanine (VA), phenylalanine-lysine (FK), and glycine-glycine-phenylalanine-glycine (GGFG). In some embodiments, this disclosure provides an antibody-drug conjugate wherein the linker is selected from maleimide-hexanoyl-valine-citrulline-p-aminobenzyloxycarbonyl (MC-VC-PAB), maleimide-hexanoyl-valine-alanine (MC-VA), maleimide-butyric acid-valine-citrulline (MB-VC), maleimide-hexanoyl-glycine-glycine-phenylalanine-glycine (MC-GGFG), valine-citrulline-p-aminobenzyloxycarbonyl (VC-PAB), GGFG, CL2A, or CL2E. In some embodiments, this disclosure provides an antibody-drug conjugate wherein the anti-CLDN6 antibody is conjugated to VC-PAB-MMAE, GGFG-MMAE, VC-PAB-MMAF, GGFG-MMAF, VC-PAB-DXd, GGFG-DXd, VC-PAB-DM1, GGFG-DM1, or CL2A-SN38. In some embodiments, this disclosure provides an antibody-drug conjugate wherein the anti-CLDN6 antibody is conjugated to MC-VC-PAB-MMAE, MC-GGFG-MMAE, MC-VC-PAB-MMAF, MC-GGFG-MMAF, MC-VC-PAB-DXd, MC-GGFG-DXd, MC-VC-PAB-DM1, or MC-GGFG-DM1. The structure of MC-VC-PAB-MMAE is as follows: MC-GGFG-DXd is a conjugate of the toxic drug DXd and the linker MC-GGFG peptide, also known as Deruxtecan, CAS No.: 1599440-13-7, with the following structure: The structure of MC-VC-PAB-DM1 (CAS No.: 1464051-44-2) is as follows: In some embodiments, this disclosure provides an antibody-drug conjugate, wherein the anti-CLDN6 antibody is selected from PiH1001, PiH1002, PiH1003, PiH1004, PiH1005, PiH1006, PiH1007, PiH1008 and PiH2001, PiH2004, PiH2005, PiH2006, PiH2007, PiH2008, PiH2009, PiH2010, PiH2011, PiH2012, PiH2012-1 (from the heavy chain of any sequence in SEQ ID NO: 149-160, 180 and SEQ ID NO: 149-160, 180 and SEQ ID NO: 149-160, 180). NO: light chain composition of any sequence in 174-178; and the anti-CLDN6 antibody is conjugated with VC-PAB-MMAE, GGFG-MMAE, VC-PAB-MMAF, GGFG-MMAF, VC-PAB-DXd, GGFG-DXd, VC-PAB-DM1, GGFG-DM1 or CL2A-SN38. For example, in some embodiments, in the antibody-drug conjugates of this disclosure, the anti-CLDN6 antibody is selected from PiH1001, PiH1002, PiH1003, PiH1004, PiH1005, PiH1006, PiH1007, PiH1008 and PiH2001, PiH2004, PiH2005, PiH2006, PiH2007, PiH2008, PiH2009, PiH2010, PiH2011, PiH2012, PiH2012-1 (from the heavy chain of any sequence in SEQ ID NO: 149-160, 180 and SEQ ID NO: 149-160, 180 and SEQ ID NO: 180). The anti-CLDN6 antibody is composed of the light chain of any sequence in SEQ ID NO: 174-178, and is conjugated with VC-PAB-MMAE; in some embodiments, in the antibody-drug conjugate of this disclosure, the anti-CLDN6 antibody is selected from PiH1001, PiH1002, PiH1003, PiH1004, PiH1005, PiH1006, PiH1007, PiH1008 and PiH2001, PiH2004, PiH2005, PiH2006, PiH2007, PiH2008, PiH2009, PiH2010, PiH2011, PiH2012, PiH2012-1 (composed of the heavy chain of any sequence in SEQ ID NO: 149-160, 180 and SEQ ID NO: 174-178). The anti-CLDN6 antibody is composed of the light chain of any sequence in SEQ ID NO: 174-178, and is conjugated with GGFG-MMAE; in some embodiments, in the antibody-drug conjugate of this disclosure, the anti-CLDN6 antibody is selected from PiH1001, PiH1002, PiH1003, PiH1004, PiH1005, PiH1006, PiH1007, PiH1008 and PiH2001, PiH2004, PiH2005, PiH2006, PiH2007, PiH2008, PiH2009, PiH2010, PiH2011, PiH2012, PiH2012-1 (composed of the heavy chain of any sequence in SEQ ID NO: 149-160, 180 and SEQ ID NO: 174-178). NO: light chain composition of any sequence in 174-178, and the anti-CLDN6 antibody is conjugated with VC-PAB-MMAF;In some embodiments, in the antibody-drug conjugates of this disclosure, the anti-CLDN6 antibody is selected from PiH1001, PiH1002, PiH1003, PiH1004, PiH1005, PiH1006, PiH1007, PiH1008 and PiH2001, PiH2004, PiH2005, PiH2006, PiH2007, PiH2008, PiH2009, PiH2010, PiH2011, PiH2012, PiH2012-1 (from the heavy chain of any sequence in SEQ ID NO: 149-160, 180 and SEQ ID NO: 149-160, 180 and SEQ ID NO: 180). The anti-CLDN6 antibody is composed of the light chain of any sequence in SEQ ID NO: 174-178, and is conjugated with GGFG-MMAF; in some embodiments, in the antibody-drug conjugate of this disclosure, the anti-CLDN6 antibody is selected from PiH1001, PiH1002, PiH1003, PiH1004, PiH1005, PiH1006, PiH1007, PiH1008 and PiH2001, PiH2004, PiH2005, PiH2006, PiH2007, PiH2008, PiH2009, PiH2010, PiH2011, PiH2012, PiH2012-1 (composed of the heavy chain of any sequence in SEQ ID NO: 149-160, 180 and SEQ ID NO: 174-178). The anti-CLDN6 antibody is composed of the light chain of any sequence in SEQ ID NO: 174-178, and is conjugated with VC-PAB-DXd; in some embodiments, in the antibody-drug conjugate of this disclosure, the anti-CLDN6 antibody is selected from PiH1001, PiH1002, PiH1003, PiH1004, PiH1005, PiH1006, PiH1007, PiH1008 and PiH2001, PiH2004, PiH2005, PiH2006, PiH2007, PiH2008, PiH2009, PiH2010, PiH2011, PiH2012, PiH2012-1 (composed of the heavy chain of any sequence in SEQ ID NO: 149-160, 180 and SEQ ID NO: 174-178). NO: light chain composition of any sequence in 174-178, and the anti-CLDN6 antibody is conjugated with GGFG-DXd;In some embodiments, in the antibody-drug conjugates of this disclosure, the anti-CLDN6 antibody is selected from PiH1001, PiH1002, PiH1003, PiH1004, PiH1005, PiH1006, PiH1007, PiH1008 and PiH2001, PiH2004, PiH2005, PiH2006, PiH2007, PiH2008, PiH2009, PiH2010, PiH2011, PiH2012, PiH2012-1 (from the heavy chain of any sequence in SEQ ID NO: 149-160, 180 and SEQ ID NO: 149-160, 180 and SEQ ID NO: 180). The anti-CLDN6 antibody is composed of the light chain of any sequence in SEQ ID NO: 174-178, and is conjugated with VC-PAB-DM1; in some embodiments, in the antibody-drug conjugate of this disclosure, the anti-CLDN6 antibody is selected from PiH1001, PiH1002, PiH1003, PiH1004, PiH1005, PiH1006, PiH1007, PiH1008 and PiH2001, PiH2004, PiH2005, PiH2006, PiH2007, PiH2008, PiH2009, PiH2010, PiH2011, PiH2012, PiH2012-1 (composed of the heavy chain of any sequence in SEQ ID NO: 149-160, 180 and SEQ ID NO: 174-178). The anti-CLDN6 antibody is composed of the light chain of any sequence in SEQ ID NO: 174-178, and is conjugated with GGFG-DM1; in some embodiments, in the antibody-drug conjugate of this disclosure, the anti-CLDN6 antibody is selected from PiH1001, PiH1002, PiH1003, PiH1004, PiH1005, PiH1006, PiH1007, PiH1008 and PiH2001, PiH2004, PiH2005, PiH2006, PiH2007, PiH2008, PiH2009, PiH2010, PiH2011, PiH2012, PiH2012-1 (composed of the heavy chain of any sequence in SEQ ID NO: 149-160, 180 and SEQ ID NO: 174-178). NO: (composed of any light chain of sequences 174-178), and the anti-CLDN6 antibody is conjugated to CL2A-SN38. In some embodiments, this disclosure provides an antibody-drug conjugate, wherein the anti-CLDN6 antibody is selected from PiH1001-M1, PiH1001-M2, PiH1001-M3, PiH1001-M4, PiH1002-M1, PiH1002-M2, PiH1002-M3, PiH1002-M4, PiH1003-M1, PiH1003-M2, PiH1003-M3, PiH1003-M4, PiH1004-M1, PiH1004-M2, PiH1004-M3, PiH1004-M4, PiH1005-M1, PiH1005-M2, PiH1005-M3, P iH1005-M4, PiH1006-M1, PiH1006-M2, PiH1006-M3, PiH1006-M4, PiH1007-M1, PiH1007-M2, PiH1007-M3, PiH1007-M4, PiH1008-M1, PiH1008-M2, PiH1008-M3, PiH1008-M4; and the anti-CLDN6 antibody is conjugated with VC-PAB-MMAE, GGFG-MMAE, VC-PAB-MMAF, GGFG-MMAF, VC-PAB-DXd, GGFG-DXd, VC-PAB-DM1, GGFG-DM1 or CL2A-SN38. For example, in some embodiments, in the antibody-drug conjugates of this disclosure, the anti-CLDN6 antibody is selected from PiH1001-M1, PiH1001-M2, PiH1001-M3, PiH1001-M4, PiH1002-M1, PiH1002-M2, PiH1002-M3, PiH1002-M4, PiH1003-M1, PiH1003-M2, PiH1003-M3, PiH1003-M4, PiH1004-M1, PiH1004-M2, PiH1004-M3, PiH 1004-M4, PiH1005-M1, PiH1005-M2, PiH1005-M3, PiH1005-M4, PiH1006-M1, PiH1006-M2, PiH1006-M3, PiH1006-M4, PiH1007-M1, PiH1007-M2, PiH1007-M3, PiH1007-M4, PiH1008-M1, PiH1008-M2, PiH1008-M3, PiH1008-M4, and the anti-CLDN6 antibody with VC-PAB-MMAE Conjugation; in some embodiments, in the antibody-drug conjugates of this disclosure, the anti-CLDN6 antibody is selected from PiH1001-M1, PiH1001-M2, PiH1001-M3, PiH1001-M4, PiH1002-M1, PiH1002-M2, PiH1002-M3, PiH1002-M4, PiH1003-M1, PiH1003-M2, PiH1003-M3, PiH1003-M4, PiH1004-M1, PiH1004-M2, PiH1004-M3, PiH1 004-M4, PiH1005-M1, PiH1005-M2, PiH1005-M3, PiH1005-M4, PiH1006-M1, PiH1006-M2, PiH1006-M3, PiH1006-M4, PiH1007-M1, PiH1007-M2, PiH1007-M3, PiH1007-M4, PiH1008-M1, PiH1008-M2, PiH1008-M3, PiH1008-M4, and the anti-CLDN6 antibody is conjugated with GGFG-MMAE;In some embodiments, in the antibody-drug conjugates of this disclosure, the anti-CLDN6 antibody is selected from PiH1001-M1, PiH1001-M2, PiH1001-M3, PiH1001-M4, PiH1002-M1, PiH1002-M2, PiH1002-M3, PiH1002-M4, PiH1003-M1, PiH1003-M2, PiH1003-M3, PiH1003-M4, PiH1004-M1, PiH1004-M2, PiH1004-M3, PiH100 4-M4, PiH1005-M1, PiH1005-M2, PiH1005-M3, PiH1005-M4, PiH1006-M1, PiH1006-M2, PiH1006-M3, PiH1006-M4, PiH1007-M1, PiH1007-M2, PiH1007-M3, PiH1007-M4, PiH1008-M1, PiH1008-M2, PiH1008-M3, PiH1008-M4, and the anti-CLDN6 antibody is conjugated with VC-PAB-MMAF. In some embodiments, in the antibody-drug conjugates of this disclosure, the anti-CLDN6 antibody is selected from PiH1001-M1, PiH1001-M2, PiH1001-M3, PiH1001-M4, PiH1002-M1, PiH1002-M2, PiH1002-M3, PiH1002-M4, PiH1003-M1, PiH1003-M2, PiH1003-M3, PiH1003-M4, PiH1004-M1, PiH1004-M2, PiH1004-M3, PiH1004-M3, PiH1004-M1, PiH1004-M2, PiH1004-M3, PiH1004-M4, PiH1004-M5, PiH1004-M6 ... 04-M4, PiH1005-M1, PiH1005-M2, PiH1005-M3, PiH1005-M4, PiH1006-M1, PiH1006-M2, PiH1006-M3, PiH1006-M4, PiH1007-M1, PiH1007-M2, PiH1007-M3, PiH1007-M4, PiH1008-M1, PiH1008-M2, PiH1008-M3, PiH1008-M4, and the anti-CLDN6 antibody is conjugated with GGFG-MMAF;In some embodiments, in the antibody-drug conjugates of this disclosure, the anti-CLDN6 antibody is selected from PiH1001-M1, PiH1001-M2, PiH1001-M3, PiH1001-M4, PiH1002-M1, PiH1002-M2, PiH1002-M3, PiH1002-M4, PiH1003-M1, PiH1003-M2, PiH1003-M3, PiH1003-M4, PiH1004-M1, PiH1004-M2, PiH1004-M3, PiH1004-M3, PiH1004-M1, PiH1004-M2 ...2, PiH1004-M3, PiH1004-M1, PiH1004-M2, PiH1004-M2, PiH1004-M2, PiH1004-M2, PiH1004-M2, PiH1004-M2, PiH 04-M4, PiH1005-M1, PiH1005-M2, PiH1005-M3, PiH1005-M4, PiH1006-M1, PiH1006-M2, PiH1006-M3, PiH1006-M4, PiH1007-M1, PiH1007-M2, PiH1007-M3, PiH1007-M4, PiH1008-M1, PiH1008-M2, PiH1008-M3, PiH1008-M4, and the anti-CLDN6 antibody is conjugated with VC-PAB-DXd. In some embodiments, in the antibody-drug conjugates of this disclosure, the anti-CLDN6 antibody is selected from PiH1001-M1, PiH1001-M2, PiH1001-M3, PiH1001-M4, PiH1002-M1, PiH1002-M2, PiH1002-M3, PiH1002-M4, PiH1003-M1, PiH1003-M2, PiH1003-M3, PiH1003-M4, PiH1004-M1, PiH1004-M2, PiH1004-M3, PiH1 004-M4, PiH1005-M1, PiH1005-M2, PiH1005-M3, PiH1005-M4, PiH1006-M1, PiH1006-M2, PiH1006-M3, PiH1006-M4, PiH1007-M1, PiH1007-M2, PiH1007-M3, PiH1007-M4, PiH1008-M1, PiH1008-M2, PiH1008-M3, PiH1008-M4, and the anti-CLDN6 antibody is conjugated with GGFG-DXd;In some embodiments, in the antibody-drug conjugates of this disclosure, the anti-CLDN6 antibody is selected from PiH1001-M1, PiH1001-M2, PiH1001-M3, PiH1001-M4, PiH1002-M1, PiH1002-M2, PiH1002-M3, PiH1002-M4, PiH1003-M1, PiH1003-M2, PiH1003-M3, PiH1003-M4, PiH1004-M1, PiH1004-M2, PiH1004-M3, PiH1004-M3, PiH1004-M1, PiH1004-M2 ...2, PiH1004-M3, PiH1004-M1, PiH1004-M2, PiH1004-M2, PiH1004-M2, PiH1004-M2, PiH1004-M2, PiH1004-M2, PiH 04-M4, PiH1005-M1, PiH1005-M2, PiH1005-M3, PiH1005-M4, PiH1006-M1, PiH1006-M2, PiH1006-M3, PiH1006-M4, PiH1007-M1, PiH1007-M2, PiH1007-M3, PiH1007-M4, PiH1008-M1, PiH1008-M2, PiH1008-M3, PiH1008-M4, and the anti-CLDN6 antibody is conjugated with VC-PAB-DM1. In some embodiments, in the antibody-drug conjugates of this disclosure, the anti-CLDN6 antibody is selected from PiH1001-M1, PiH1001-M2, PiH1001-M3, PiH1001-M4, PiH1002-M1, PiH1002-M2, PiH1002-M3, PiH1002-M4, PiH1003-M1, PiH1003-M2, PiH1003-M3, PiH1003-M4, PiH1004-M1, PiH1004-M2, PiH1004-M3, PiH1 004-M4, PiH1005-M1, PiH1005-M2, PiH1005-M3, PiH1005-M4, PiH1006-M1, PiH1006-M2, PiH1006-M3, PiH1006-M4, PiH1007-M1, PiH1007-M2, PiH1007-M3, PiH1007-M4, PiH1008-M1, PiH1008-M2, PiH1008-M3, PiH1008-M4, and the anti-CLDN6 antibody is conjugated to GGFG-DM1;In some embodiments, in the antibody-drug conjugates of this disclosure, the anti-CLDN6 antibody is selected from PiH1001-M1, PiH1001-M2, PiH1001-M3, PiH1001-M4, PiH1002-M1, PiH1002-M2, PiH1002-M3, PiH1002-M4, PiH1003-M1, PiH1003-M2, PiH1003-M3, PiH1003-M4, PiH1004-M1, PiH1004-M2, PiH1004-M3, PiH1004-M3, PiH1004-M1, PiH1004-M2 ...2, PiH1004-M3, PiH1004-M1, PiH1004-M2, PiH1004-M2, PiH1004-M2, PiH1004-M2, PiH1004-M2, PiH1004-M2, PiH The following are listed: 04-M4, PiH1005-M1, PiH1005-M2, PiH1005-M3, PiH1005-M4, PiH1006-M1, PiH1006-M2, PiH1006-M3, PiH1006-M4, PiH1007-M1, PiH1007-M2, PiH1007-M3, PiH1007-M4, PiH1008-M1, PiH1008-M2, PiH1008-M3, and PiH1008-M4, and the anti-CLDN6 antibody is conjugated to CL2A-SN38. In some embodiments, this disclosure provides an antibody-drug conjugate, wherein the anti-CLDN6 antibody is selected from PiH1001, PiH1002, PiH1003, PiH1004, PiH1005, PiH1006, PiH1007, PiH1008 and PiH2001, PiH2004, PiH2005, PiH2006, PiH2007, PiH2008, PiH2009, PiH2010, PiH2011, PiH2012, PiH2012-1 (from the heavy chain of any sequence in SEQ ID NO: 149-160, 180 and SEQ ID NO: 149-160, 180 and SEQ ID NO: 149-160, 180). NO: light chain composition of any sequence in 174-178; and the anti-CLDN6 antibody is conjugated with MC-VC-PAB-MMAE, MC-GGFG-MMAE, MC-VC-PAB-MMAF, MC-GGFG-MMAF, MC-VC-PAB-DXd, MC-GGFG-DXd, MC-VC-PAB-DM1 or MC-GGFG-DM1. For example, in some embodiments, in the antibody-drug conjugates of this disclosure, the anti-CLDN6 antibody is selected from PiH1001, PiH1002, PiH1003, PiH1004, PiH1005, PiH1006, PiH1007, PiH1008 and PiH2001, PiH2004, PiH2005, PiH2006, PiH2007, PiH2008, PiH2009, PiH2010, PiH2011, PiH2012, PiH2012-1 (from the heavy chain of any sequence in SEQ ID NO: 149-160, 180 and SEQ ID NO: 149-160, 180 and SEQ ID NO: 180). The anti-CLDN6 antibody is composed of the light chain of any sequence in SEQ ID NO: 174-178, and is conjugated with MC-VC-PAB-MMAE; in some embodiments, in the antibody-drug conjugate of this disclosure, the anti-CLDN6 antibody is selected from PiH1001, PiH1002, PiH1003, PiH1004, PiH1005, PiH1006, PiH1007, PiH1008 and PiH2001, PiH2004, PiH2005, PiH2006, PiH2007, PiH2008, PiH2009, PiH2010, PiH2011, PiH2012, PiH2012-1 (composed of the heavy chain of any sequence in SEQ ID NO: 149-160, 180 and SEQ ID NO: 174-178). The anti-CLDN6 antibody is composed of the light chain of any sequence in SEQ ID NO: 174-178, and is conjugated with MC-GGFG-MMAE; in some embodiments, in the antibody-drug conjugate of this disclosure, the anti-CLDN6 antibody is selected from PiH1001, PiH1002, PiH1003, PiH1004, PiH1005, PiH1006, PiH1007, PiH1008 and PiH2001, PiH2004, PiH2005, PiH2006, PiH2007, PiH2008, PiH2009, PiH2010, PiH2011, PiH2012, PiH2012-1 (composed of the heavy chain of any sequence in SEQ ID NO: 149-160, 180 and SEQ ID NO: 174-178). NO: light chain composition of any sequence in 174-178, and the anti-CLDN6 antibody is conjugated with MC-VC-PAB-MMAF;In some embodiments, in the antibody-drug conjugates of this disclosure, the anti-CLDN6 antibody is selected from PiH1001, PiH1002, PiH1003, PiH1004, PiH1005, PiH1006, PiH1007, PiH1008 and PiH2001, PiH2004, PiH2005, PiH2006, PiH2007, PiH2008, PiH2009, PiH2010, PiH2011, PiH2012, PiH2012-1 (from the heavy chain of any sequence in SEQ ID NO: 149-160, 180 and SEQ ID NO: 149-160, 180 and SEQ ID NO: 180). The anti-CLDN6 antibody is composed of the light chain of any sequence in SEQ ID NO: 174-178, and is conjugated with MC-GGFG-MMAF; in some embodiments, in the antibody-drug conjugate of this disclosure, the anti-CLDN6 antibody is selected from PiH1001, PiH1002, PiH1003, PiH1004, PiH1005, PiH1006, PiH1007, PiH1008 and PiH2001, PiH2004, PiH2005, PiH2006, PiH2007, PiH2008, PiH2009, PiH2010, PiH2011, PiH2012, PiH2012-1 (composed of the heavy chain of any sequence in SEQ ID NO: 149-160, 180 and SEQ ID NO: 174-178). The anti-CLDN6 antibody is composed of the light chain of any sequence in SEQ ID NO: 174-178, and is conjugated with MC-VC-PAB-DXd; in some embodiments, in the antibody-drug conjugate of this disclosure, the anti-CLDN6 antibody is selected from PiH1001, PiH1002, PiH1003, PiH1004, PiH1005, PiH1006, PiH1007, PiH1008 and PiH2001, PiH2004, PiH2005, PiH2006, PiH2007, PiH2008, PiH2009, PiH2010, PiH2011, PiH2012, PiH2012-1 (composed of the heavy chain of any sequence in SEQ ID NO: 149-160, 180 and SEQ ID NO: 174-178). NO: light chain composition of any sequence in 174-178, and the anti-CLDN6 antibody is conjugated with MC-GGFG-DXd;In some embodiments, in the antibody-drug conjugates of this disclosure, the anti-CLDN6 antibody is selected from PiH1001, PiH1002, PiH1003, PiH1004, PiH1005, PiH1006, PiH1007, PiH1008 and PiH2001, PiH2004, PiH2005, PiH2006, PiH2007, PiH2008, PiH2009, PiH2010, PiH2011, PiH2012, PiH2012-1 (from the heavy chain of any sequence in SEQ ID NO: 149-160, 180 and SEQ ID NO: 149-160, 180 and SEQ ID NO: 180). The anti-CLDN6 antibody is composed of the light chain of any sequence in SEQ ID NO: 174-178, and is conjugated with MC-VC-PAB-DM1; in some embodiments, in the antibody-drug conjugate of this disclosure, the anti-CLDN6 antibody is selected from PiH1001, PiH1002, PiH1003, PiH1004, PiH1005, PiH1006, PiH1007, PiH1008 and PiH2001, PiH2004, PiH2005, PiH2006, PiH2007, PiH2008, PiH2009, PiH2010, PiH2011, PiH2012, PiH2012-1 (composed of the heavy chain of any sequence in SEQ ID NO: 149-160, 180 and SEQ ID NO: 174-178). NO: (composed of any light chain of sequences 174-178), and the anti-CLDN6 antibody is conjugated to MC-GGFG-DM1. In some embodiments, this disclosure provides an antibody-drug conjugate, wherein the anti-CLDN6 antibody is selected from PiH1001-M1, PiH1001-M2, PiH1001-M3, PiH1001-M4, PiH1002-M1, PiH1002-M2, PiH1002-M3, PiH1002-M4, PiH1003-M1, PiH1003-M2, PiH1003-M3, PiH1003-M4, PiH1004-M1, PiH1004-M2, PiH1004-M3, PiH1004-M4, PiH1005-M1, PiH1005-M2, PiH1005-M3, PiH1005- M4, PiH1006-M1, PiH1006-M2, PiH1006-M3, PiH1006-M4, PiH1007-M1, PiH1007-M2, PiH1007-M3, PiH1007-M4, PiH1008-M1, PiH1008-M2, PiH1008-M3, PiH1008-M4; and the anti-CLDN6 antibody is conjugated with MC-VC-PAB-MMAE, MC-GGFG-MMAE, MC-VC-PAB-MMAF, MC-GGFG-MMAF, MC-VC-PAB-DXd, MC-GGFG-DXd, MC-VC-PAB-DM1 or MC-GGFG-DM1. For example, in some embodiments, in the antibody-drug conjugates of this disclosure, the anti-CLDN6 antibody is selected from PiH1001-M1, PiH1001-M2, PiH1001-M3, PiH1001-M4, PiH1002-M1, PiH1002-M2, PiH1002-M3, PiH1002-M4, PiH1003-M1, PiH1003-M2, PiH1003-M3, PiH1003-M4, PiH1004-M1, PiH1004-M2, PiH1004-M3, PiH1004-M3, PiH1001-M4 ... 04-M4, PiH1005-M1, PiH1005-M2, PiH1005-M3, PiH1005-M4, PiH1006-M1, PiH1006-M2, PiH1006-M3, PiH1006-M4, PiH1007-M1, PiH1007-M2, PiH1007-M3, PiH1007-M4, PiH1008-M1, PiH1008-M2, PiH1008-M3, PiH1008-M4, and the anti-CLDN6 antibody with MC-VC-PAB-MMAE Conjugation; in some embodiments, in the antibody-drug conjugates of this disclosure, the anti-CLDN6 antibody is selected from PiH1001-M1, PiH1001-M2, PiH1001-M3, PiH1001-M4, PiH1002-M1, PiH1002-M2, PiH1002-M3, PiH1002-M4, PiH1003-M1, PiH1003-M2, PiH1003-M3, PiH1003-M4, PiH1004-M1, PiH1004-M2, PiH1004-M3, PiH1004-M3, PiH1004-M1, PiH1004-M2, PiH1004-M3, PiH1004-M4 ... 04-M4, PiH1005-M1, PiH1005-M2, PiH1005-M3, PiH1005-M4, PiH1006-M1, PiH1006-M2, PiH1006-M3, PiH1006-M4, PiH1007-M1, PiH1007-M2, PiH1007-M3, PiH1007-M4, PiH1008-M1, PiH1008-M2, PiH1008-M3, PiH1008-M4, and the anti-CLDN6 antibody is conjugated with MC-GGFG-MMAE;In some embodiments, in the antibody-drug conjugates of this disclosure, the anti-CLDN6 antibody is selected from PiH1001-M1, PiH1001-M2, PiH1001-M3, PiH1001-M4, PiH1002-M1, PiH1002-M2, PiH1002-M3, PiH1002-M4, PiH1003-M1, PiH1003-M2, PiH1003-M3, PiH1003-M4, PiH1004-M1, PiH1004-M2, PiH1004-M3, and PiH1004. -M4, PiH1005-M1, PiH1005-M2, PiH1005-M3, PiH1005-M4, PiH1006-M1, PiH1006-M2, PiH1006-M3, PiH1006-M4, PiH1007-M1, PiH1007-M2, PiH1007-M3, PiH1007-M4, PiH1008-M1, PiH1008-M2, PiH1008-M3, PiH1008-M4, and the anti-CLDN6 antibody is conjugated with MC-VC-PAB-MMAF. In some embodiments, in the antibody-drug conjugates of this disclosure, the anti-CLDN6 antibody is selected from PiH1001-M1, PiH1001-M2, PiH1001-M3, PiH1001-M4, PiH1002-M1, PiH1002-M2, PiH1002-M3, PiH1002-M4, PiH1003-M1, PiH1003-M2, PiH1003-M3, PiH1003-M4, PiH1004-M1, PiH1004-M2, PiH1004-M3, PiH100 4-M4, PiH1005-M1, PiH1005-M2, PiH1005-M3, PiH1005-M4, PiH1006-M1, PiH1006-M2, PiH1006-M3, PiH1006-M4, PiH1007-M1, PiH1007-M2, PiH1007-M3, PiH1007-M4, PiH1008-M1, PiH1008-M2, PiH1008-M3, PiH1008-M4, and the anti-CLDN6 antibody is conjugated with MC-GGFG-MMAF;In some embodiments, in the antibody-drug conjugates of this disclosure, the anti-CLDN6 antibody is selected from PiH1001-M1, PiH1001-M2, PiH1001-M3, PiH1001-M4, PiH1002-M1, PiH1002-M2, PiH1002-M3, PiH1002-M4, PiH1003-M1, PiH1003-M2, PiH1003-M3, PiH1003-M4, PiH1004-M1, PiH1004-M2, PiH1004-M3, and PiH1004. -M4, PiH1005-M1, PiH1005-M2, PiH1005-M3, PiH1005-M4, PiH1006-M1, PiH1006-M2, PiH1006-M3, PiH1006-M4, PiH1007-M1, PiH1007-M2, PiH1007-M3, PiH1007-M4, PiH1008-M1, PiH1008-M2, PiH1008-M3, PiH1008-M4, and the anti-CLDN6 antibody is conjugated with MC-VC-PAB-DXd. In some embodiments, in the antibody-drug conjugates of this disclosure, the anti-CLDN6 antibody is selected from PiH1001-M1, PiH1001-M2, PiH1001-M3, PiH1001-M4, PiH1002-M1, PiH1002-M2, PiH1002-M3, PiH1002-M4, PiH1003-M1, PiH1003-M2, PiH1003-M3, PiH1003-M4, PiH1004-M1, PiH1004-M2, PiH1004-M3, PiH100 4-M4, PiH1005-M1, PiH1005-M2, PiH1005-M3, PiH1005-M4, PiH1006-M1, PiH1006-M2, PiH1006-M3, PiH1006-M4, PiH1007-M1, PiH1007-M2, PiH1007-M3, PiH1007-M4, PiH1008-M1, PiH1008-M2, PiH1008-M3, PiH1008-M4, and the anti-CLDN6 antibody is conjugated with MC-GGFG-DXd;In some embodiments, in the antibody-drug conjugates of this disclosure, the anti-CLDN6 antibody is selected from PiH1001-M1, PiH1001-M2, PiH1001-M3, PiH1001-M4, PiH1002-M1, PiH1002-M2, PiH1002-M3, PiH1002-M4, PiH1003-M1, PiH1003-M2, PiH1003-M3, PiH1003-M4, PiH1004-M1, PiH1004-M2, PiH1004-M3, PiH100 4-M4, PiH1005-M1, PiH1005-M2, PiH1005-M3, PiH1005-M4, PiH1006-M1, PiH1006-M2, PiH1006-M3, PiH1006-M4, PiH1007-M1, PiH1007-M2, PiH1007-M3, PiH1007-M4, PiH1008-M1, PiH1008-M2, PiH1008-M3, PiH1008-M4, and the anti-CLDN6 antibody with MC-VC-PAB-DM1 Conjugation; in some embodiments, in the antibody-drug conjugates of this disclosure, the anti-CLDN6 antibody is selected from PiH1001-M1, PiH1001-M2, PiH1001-M3, PiH1001-M4, PiH1002-M1, PiH1002-M2, PiH1002-M3, PiH1002-M4, PiH1003-M1, PiH1003-M2, PiH1003-M3, PiH1003-M4, PiH1004-M1, PiH1004-M2, PiH1004-M3, PiH The anti-CLDN6 antibody is conjugated with MC-GGFG-DM1. (The list includes: 1004-M4, PiH1005-M1, PiH1005-M2, PiH1005-M3, PiH1005-M4, PiH1006-M1, PiH1006-M2, PiH1006-M3, PiH1006-M4, PiH1007-M1, PiH1007-M2, PiH1007-M3, PiH1007-M4, PiH1008-M1, PiH1008-M2, PiH1008-M3, and PiH1008-M4.) The drug moiety to antigen-binding protein ratio (DAR) represents the number of drug moieties linked to each antigen-binding molecule. In some embodiments, the DAR is in the range of 1 to 15, 1 to 10, 1 to 9, 1 to 8, 1 to 7, 1 to 6, 1 to 5, 1 to 4, 1 to 3, or 1 to 2. In some embodiments, the DAR is in the range of 2 to 10, 2 to 9, 2 to 8, 2 to 7, 2 to 6, 2 to 5, 2 to 4, or 2 to 3. In other embodiments, the DAR is about 2, about 2.5, about 3, about 4, about 5, or about 6, about 7, or about 8. In some embodiments, the DAR is in the range of about 2 to about 4. In some embodiments, the DAR is in the range of about 6 to about 8. The DAR can be characterized by conventional methods such as mass spectrometry, UV / Vis spectroscopy, ELISA assay, and / or HPLC. In some implementations, each antibody molecule is conjugated to an average of 3 to 4 molecules of olistatin or its derivatives (3 to 4 for DAR). In some implementations, each antibody molecule is conjugated to an average of 6 to 8 molecules of camptothecin derivatives (6 to 8 for DAR). In some implementations, each antibody molecule is conjugated to an average of 3 to 4 molecules of maytansin or its derivatives (3 to 4 for DAR). In some embodiments, the conjugate is a homogeneous conjugate in which a substantial percentage of the antigen-binding protein is conjugated to a defined number of pharmaceutical moieties. In some embodiments, the homogeneous conjugate contains 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 DARs. In some embodiments, the homogeneous conjugate contains 2, 4, 6, or 8 DARs. In a preferred embodiment, the homogeneous conjugate contains 4 DARs. In other preferred embodiments, the homogeneous conjugate contains 2 DARs. In other preferred embodiments, the homogeneous conjugate contains 8 DARs. In some embodiments, the homogeneous conjugate comprises 70%, 71%, 72%, 73%, 74%, 75%, 76%, 77%, 78%, 79%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% of a conjugate with a defined DAR. In some embodiments, the homogeneous conjugate comprises about 70%, 71%, 72%, 73%, 74%, 75%, 76%, 77%, 78%, 79%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% of a conjugate with a defined DAR. In some embodiments, the homogeneous conjugate comprises a non-Gaussian or quasi-Gaussian DAR distribution. In some embodiments, the homogeneity of the homogeneous conjugate is determined by chromatography, such as HPLC or any suitable chromatography. In some embodiments, the chromatogram is a HIC chromatogram. The homogeneous conjugate can be generated by site-specific conjugation. In this regard, conjugates also include antibodies that are partially linked (e.g., covalently linked) to at least one toxic drug, such as one or more molecules of the same drug linked (e.g., covalently linked) to an antibody molecule, and / or wherein different drugs are linked (e.g., covalently linked) to antibody molecules. In the latter case, one or more molecules of each different drug may be linked to an antibody molecule or a combination thereof (e.g., one molecule of one drug is linked while several molecules of another drug are linked). Pharmaceutical Composition In some aspects, this disclosure relates to pharmaceutical compositions, providing a pharmaceutical composition or kit comprising an antibody or antigen-binding portion thereof as described above, a nucleic acid molecule as described above, a carrier as described above, a host cell as described above, a conjugate as described above, or an antibody-drug conjugate as described above; and a pharmaceutically acceptable carrier. The pharmaceutical composition may optionally contain one or more additional pharmaceutically active ingredients, such as another antibody or drug (e.g., sorafenib). The pharmaceutical compositions disclosed herein may also be administered in combination with, for example, another immunostimulant, anticancer agent, antiviral agent, or vaccine, such that the anti-CLDN6 antibody enhances the immune response to the vaccine. Pharmaceutically acceptable carriers may include, for example, pharmaceutically acceptable liquid, gel, or solid carriers, aqueous media, non-aqueous media, antimicrobial agents, isotonic agents, buffers, antioxidants, anesthetics, suspending / dispersing agents, chelating agents, diluents, adjuvants, excipients, or non-toxic excipients, combinations or more of various components known in the art. Suitable components may include, for example, antioxidants, fillers, binders, disintegrants, buffers, preservatives, lubricants, flavorings, thickeners, colorants, emulsifiers, or stabilizers such as sugars and cyclodextrins. Suitable antioxidants may include, for example, methionine, ascorbic acid, EDTA, sodium thiosulfate, platinum, catalase, citric acid, cysteine, mercaptoglycerol, mercaptoacetic acid, mercaptosorbitol, butylated methyl anisole, butylated hydroxytoluene, and / or propyl arsenate. As disclosed in this disclosure, an antibody or its antigen-binding moiety containing a composition disclosed herein can be oxidized in a solvent containing one or more antioxidants such as methionine that reduce the antibody or its antigen-binding moiety. Redox reactions can prevent or reduce the decrease in binding affinity, thereby enhancing antibody stability and extending shelf life. Therefore, in some embodiments, this disclosure provides compositions comprising one or more antibodies or their antigen-binding moieties and one or more antioxidants such as methionine. This disclosure further provides various methods in which an antibody or its antigen-binding moieties are mixed with one or more antioxidants such as methionine. Thus, antibodies or their antigen-binding portions can be protected from oxidation to prolong their shelf life and / or increase their activity. To further illustrate, pharmaceutically acceptable carriers may include, for example, aqueous media such as sodium chloride injection, Ringer's injection, isotonic dextran injection, sterile water injection, or dextran and lactated Ringer's injection; non-aqueous media such as non-volatile plant-derived oils, cottonseed oil, corn oil, sesame oil, or peanut oil; antimicrobial agents at antibacterial or antifungal concentrations; isotonic agents such as sodium chloride or glucose; buffers such as phosphate or citrate buffers; antioxidants such as sodium bisulfate; local anesthetics such as procaine hydrochloride; suspending and dispersing agents such as sodium carboxymethyl cellulose, hydroxypropyl methylcellulose, or polyvinylpyrrolidone; emulsifiers such as polysorbate 80 (TWEEN-80); isolating agents or chelating agents such as EDTA (ethylenediaminetetraacetic acid) or EGTA (ethylene glycol tetraacetic acid); ethanol; polyethylene glycol; propylene glycol; sodium hydroxide; hydrochloric acid; citric acid; or lactic acid. Antimicrobial agents used as carriers can be added to pharmaceutical compositions containing phenols or cresols, mercury preparations, benzyl alcohol, chlorobutanol, methylparaben and propylparaben, thimerosal, benzalkonium chloride, and benzyl chloride in multi-dose containers. Suitable excipients may include, for example, water, saline, dextran, glycerol, or ethanol. Suitable non-toxic adjuvants may include, for example, wetting agents or emulsifiers, pH buffers, stabilizers, solubility enhancers, or agents such as sodium acetate, sorbitol monolaurate, triethanolamine oleate, or cyclodextrin. Application, formulation and dosage The pharmaceutical compositions disclosed herein can be administered to subjects in need via various routes, including but not limited to oral, intravenous, intra-arterial, subcutaneous, parenteral, intranasal, intramuscular, intracranial, intracardiac, intraventricular, intratracheal, oral, rectal, intraperitoneal, intradermal, topical, percutaneous, and intrathecal administration, or via implantation or inhalation. The compositions disclosed herein can be formulated into solid, semi-solid, liquid, or gaseous forms; including but not limited to tablets, capsules, powders, granules, ointments, solutions, suppositories, enemas, injections, inhalers, and aerosols. Appropriate formulations and routes of administration can be selected based on the intended application and treatment regimen. Suitable formulations for enteral administration include hard or soft gelatin capsules, pills, tablets (including coated tablets), elixirs, suspensions, syrups, or inhalers and their controlled-release formulations. Formulations suitable for parenteral administration (e.g., by injection) include aqueous or non-aqueous, isotonic, pyrogen-free, sterile liquids (e.g., solutions, suspensions) in which the active ingredient is dissolved, suspended, or otherwise provided (e.g., in liposomes or other microparticles). These liquids may additionally contain other pharmaceutically acceptable components, such as antioxidants, buffers, preservatives, stabilizers, antibacterial agents, suspending agents, thickeners, and solutes that make the formulation isotonic with the intended recipient's blood (or other relevant bodily fluids). Examples of excipients include, for example, water, alcohols, polyols, glycerol, vegetable oils, etc. Examples of isotonic carriers suitable for such formulations include sodium chloride injection, Ringer's solution, or lactated Ringer's solution. Similarly, specific dosing regimens (including dose, time, and repetition) will depend on the specific individual and their medical history, as well as empirical considerations such as pharmacokinetic parameters (e.g., half-life, clearance, etc.). The requirements for effective drug carriers for injectable formulations / compositions are well known to those skilled in the art (see, for example, Pharmaceutics and Pharmacy Practice, JBLippincott Company, Philadelphia, PA, edited by Banker and Chalmers, pp. 238-250 (1982), and ASHP Handbook on Injectable Drugs, Toissel, 4th edition, pp. 622-630 (1986)). The frequency of administration can be determined and adjusted during treatment, and is based on reducing the number of proliferating or tumorigenic cells, maintaining this reduction in tumor cells, reducing tumor cell proliferation, or delaying the development of metastasis. In some embodiments, the administered dose can be adjusted or reduced to control potential side effects and / or toxicity. Alternatively, a continuously releasing formulation of the therapeutic composition disclosed herein may be suitable. Those skilled in the art will understand that appropriate dosages can vary from patient to patient. Determining the optimal dosage typically involves balancing the level of therapeutic benefit with any risks or adverse side effects. The chosen dosage level will depend on a variety of factors, including but not limited to the activity of the specific compound, administration, timing of administration, compound clearance rate, duration of treatment, other drugs, compounds and / or materials used in combination, severity of the condition, and species, the patient's sex, age, weight, condition, general health status, and previous medical history. The amount of compound and route of administration are ultimately determined by a physician, veterinarian, or clinician, but a dosage is typically chosen to achieve a local concentration at the site of action to achieve the desired effect without causing substantial harmful or adverse side effects. Generally, the antibodies or their antigen-binding portions, as well as antibody-drug conjugates disclosed herein, can be administered in a variety of ranges. These include about 5 μg / kg body weight to about 100 mg / kg body weight per dose; about 50 μg / kg body weight to about 5 mg / kg body weight per dose; and about 100 μg / kg body weight to about 10 mg / kg body weight per dose. Other ranges include about 100 μg / kg body weight to about 20 mg / kg body weight per dose and about 0.5 mg / kg body weight to about 20 mg / kg body weight per dose. In some embodiments, the dose is at least about 100 μg / kg body weight, at least about 250 μg / kg body weight, at least about 750 μg / kg body weight, at least about 3 mg / kg body weight, at least about 5 mg / kg body weight, and at least about 10 mg / kg body weight. In any case, the antibodies or their antigen-binding portions, as well as antibody-drug conjugates disclosed herein, are preferably administered to subjects in need as required. Those skilled in the art can determine the frequency of administration, for example, based on considerations by the attending physician regarding the condition being treated, the age of the subject being treated, the severity of the condition being treated, and the general health condition of the subject being treated. In some preferred embodiments, a treatment procedure involving the antibody or its antigen-binding portion thereof, as well as antibody-drug conjugates, of this disclosure will comprise multiple doses of the selected pharmaceutical product administered over several weeks or months. More specifically, the antibody or its antigen-binding portion thereof, as well as antibody-drug conjugates of this disclosure, may be administered daily, every two days, every four days, weekly, every ten days, every two weeks, every three weeks, monthly, every six weeks, every two months, every ten weeks, or every three months. In this regard, it is understood that the dosage or interval may be varied or adjusted based on patient response and clinical practice. The dosage and regimen of the disclosed therapeutic composition may also be determined empirically in individuals receiving one or more administrations. For example, an incremental dose of the therapeutic composition as described herein may be administered to an individual. In selected embodiments, the dosage may be gradually increased, decreased, or mitigated based on empirical determination or observed side effects or toxicities. To assess the efficacy of the selected composition, biomarkers of a specific disease, condition, or disease can be tracked as previously described. For cancer, these include direct measurement of tumor size by palpation or visual observation, indirect measurement of tumor size by X-ray or other imaging techniques; improvement assessed by direct tumor biopsy and microscopic examination of tumor samples; measurement of indirect tumor biomarkers (e.g., PSA for prostate cancer) or tumorigenic antigens identified according to the methods described herein; reduction of pain or paralysis; improvement of tumor-related speech, vision, breathing, or other disabilities; increased appetite; or improvement in quality of life or prolonged survival as measured by administered tests. Those skilled in the art will understand that the dosage will vary depending on the individual, the type of tumor, the stage of the tumor, whether the tumor has begun to metastasize to other sites within the individual, and past and concurrent treatments. Compatible formulations intended for parenteral administration (e.g., intravenous injection) will comprise an antibody or its antigen-binding moiety as disclosed herein, and an antibody-drug conjugate, at a concentration of about 10 μg / mL to about 100 mg / mL. In some selected embodiments, the concentrations of the antibody or its antigen-binding moiety, and the antibody-drug conjugate, will include 20 μg / mL, 40 μg / mL, 60 μg / mL, 80 μg / mL, 100 μg / mL, 200 μg / mL, 300 μg / mL, 400 μg / mL, 500 μg / mL, 600 μg / mL, 700 μg / mL, 800 μg / mL, 900 μg / mL, or 1 mg / mL. In other preferred embodiments, the antibody-drug conjugate (ADC) concentration will include 2 mg / mL, 3 mg / mL, 4 mg / mL, 5 mg / mL, 6 mg / mL, 8 mg / mL, 10 mg / mL, 12 mg / mL, 14 mg / mL, 16 mg / mL, 18 mg / mL, 20 mg / mL, 25 mg / mL, 30 mg / mL, 35 mg / mL, 40 mg / mL, 45 mg / mL, 50 mg / mL, 60 mg / mL, 70 mg / mL, 80 mg / mL, 90 mg / mL, or 100 mg / mL. The disclosed antibody can be co-administered with one or more therapeutic agents (e.g., cytotoxic agents, radiotoxic agents, antitumor agents, antiangiogenic agents, or immunosuppressants) to reduce the induction of an immune response against the disclosed antibody. The antibody can be conjugated to the therapeutic agent (as an immune complex) or administered separately from the therapeutic agent. In the case of separate administration, the antibody can be administered before, after, or simultaneously with the therapeutic agent, or co-administered with other known treatments (e.g., anticancer treatments (e.g., radiotherapy, chemotherapy)). In the context of treatment administration, the terms "combination" or "co-administration" as used herein refer to the use of more than one treatment or therapeutic agent. The use of the term "combination" does not limit the order in which treatments or therapeutic agents are administered to the subject. Treatments or therapeutic agents may be administered before, simultaneously with, or after administering a second treatment or therapeutic agent to the patient. Preferably, treatments or therapeutic agents are administered to the subject in a specific order, amount, and / or at specific time intervals so that the treatments or therapeutic agents can work together. In one specific embodiment, treatments or therapeutic agents are administered to the subject in a specific order, amount, and / or at specific time intervals so that they provide an increased benefit compared to if administered in other ways (particularly independently of each other). Preferably, the increased benefit is a synergistic effect. Medical Use The antibodies, antibody-drug conjugates, pharmaceutical compositions, and methods disclosed herein have numerous in vitro and in vivo uses, including, for example, the detection of CLDN6 or the enhancement of immune responses. For instance, these molecules can be administered in vitro or ex vivo to cultured cells, or, for example, in vivo to human subjects. Preferred subjects include mammals, such as people / patients in need. In the context of this disclosure, mammals include humans, non-human primates, domesticated animals such as dogs, cats, sheep, cattle, goats, pigs, horses, etc., laboratory animals such as mice, rats, rabbits, guinea pigs, etc., and captive animals such as animals in zoos. This disclosure further provides a method for detecting the presence of human CLDN6 antigen in a sample or measuring the amount of human CLDN6 antigen, comprising contacting a sample and a control sample with a monoclonal antibody or its antigen-binding portion that specifically binds to human CLDN6, under conditions allowing the formation of a complex between an antibody or a portion thereof and human CLDN6. The formation of the complex is then detected, wherein a difference in complex formation between the samples compared to the control sample indicates the presence of human CLDN6 antigen in the sample. Furthermore, the anti-CLDN6 antibody of this disclosure can be used to purify human CLDN6 by immunoaffinity purification. In some embodiments, the sample comprises cells. This disclosure also provides the use of antibody-drug conjugates, pharmaceutical compositions, or kits in the preparation of medicaments for treating diseases associated with CLDN6 expression or characterized by CLDN6 binding to its cell surface. "Diseases associated with CLDN6 expression and characterized by CLDN6 binding to its cell surface" are described below. Treatment of diseases including cancer In some aspects, this disclosure provides methods for treating diseases in mammals, comprising administering to a subject (e.g., a human) a therapeutically effective amount of the antibody disclosed herein or its antigen-binding moiety, antibody-pharmaceutical conjugate, or pharmaceutical composition. For example, the disease is cancer. In some aspects, the antibodies disclosed herein possess one or more of the following activities: (i) killing cells expressing CLDN6; (ii) inhibiting the proliferation of cells expressing CLDN6; (iii) inhibiting colony formation of cells expressing CLDN6; (iv) mediating tumor remission (e.g., reduction in size), preferably complete remission (e.g., complete disappearance); (v) preventing tumor formation or reformation; and (vi) inhibiting the metastasis of cells expressing CLDN6. Therefore, the antibodies can be used for one or more of the foregoing purposes (especially when administered to a patient). As described herein, the disclosed antibodies possess one or more activities that can be therapeutically applied to kill and / or inhibit cell proliferation. In particular, they can be used to kill cells, inhibit cell proliferation, and / or inhibit cell colony formation for the treatment or prevention of cancer (including cancer metastasis). Inhibition of cell proliferation, colony formation, and / or metastasis can be applied, especially for the treatment or prevention of cancer metastasis and the metastatic spread of cancer cells. In some respects, the antibodies of this disclosure mediate the killing of cells (e.g., cells expressing human CLDN6, such as tumor cells, or tumor cells expressing CLDN6) by inducing antibody-dependent cell cytotoxicity (ADCC)-mediated lysis, apoptosis, homogeneous adhesion, and / or phagocytosis. In some respects, the antibodies disclosed herein mediate the killing of cells (e.g., cells expressing human CLDN6, such as tumor cells, or tumor cells expressing CLDN6) by inducing complement-dependent cytotoxicity (CDC)-mediated lysis, apoptosis, homogeneous adhesion, and / or phagocytosis. However, this disclosure also includes embodiments in which the antibody exerts the activities described herein (e.g., killing cells and / or inhibiting one or more cellular activities (e.g., cell proliferation and / or colony formation) without inducing complement-dependent cytotoxicity (CDC)-mediated lysis, antibody-dependent cell cytotoxicity (ADCC)-mediated lysis, apoptosis, homogeneous adhesion, and / or phagocytosis). The antibodies disclosed herein can interact with components of the immune system, preferably through ADCC or CDC interactions. Furthermore, the antibodies disclosed herein can also exert their effects by simply binding to CLDN6 on the cell surface (thus, for example, blocking cell proliferation). In some aspects, ADCC-mediated cell lysis occurs in the presence of effector cells, and in some specific embodiments, the effector cells are selected from monocytes, mononuclear cells, NK cells, and neutrophils (PMNs). In some specific implementations, phagocytosis is carried out by macrophages. In some respects, the antibodies of this disclosure exhibit one or more immune effector functions against cells carrying CLDN6, particularly those in their native conformation, wherein the one or more immune effector functions are preferably selected from complement-dependent cytotoxicity (CDC), antibody-dependent cell-mediated cytotoxicity (ADCC), apoptosis induction, and proliferation inhibition. The antibodies disclosed herein can interact with components of the immune system, preferably through ADCC and / or CDC interactions. Furthermore, the antibodies disclosed herein can also exert their effects by simply binding to CLDN6 (e.g., human CLDN6) on the cell surface (thus, for example, blocking cell proliferation). In some aspects, this disclosure provides a method for treating or determining the prognosis of a disease characterized by CLDN6 expression and / or CLDN6 binding to its cell surface in a subject, comprising administering an effective dose of the antibody or its antigen-binding portion, the nucleic acid molecule, the vector, the host cell, the conjugate, the antibody-drug conjugate, or the pharmaceutical composition or kit to the desired subject. In some aspects, this disclosure provides an antibody or its antigen-binding portion, the nucleic acid molecule, the vector, the host cell, the conjugate, the antibody-drug conjugate, or the pharmaceutical composition or kit in a method for treating or determining the prognosis of a disease characterized by CLDN6 expression or CLDN6 binding to its cell surface in a subject. In some aspects, this disclosure provides the use of the antibody or its antigen-binding portion, the nucleic acid molecule, the vector, the host cell, the conjugate, the antibody-drug conjugate, or the pharmaceutical composition or kit in the preparation of reagents for treating diseases associated with CLDN6 expression or for determining their prognosis. According to this disclosure, "diseases associated with CLDN6 expression and characterized by CLDN6 binding to its cell surface" means that, compared to the state in healthy tissues or organs, the expression and binding of CLDN6 in the cells of diseased tissues or organs are preferably elevated. Elevation means an increase of at least 10%, particularly at least 20%, at least 50%, at least 100%, at least 200%, at least 500%, at least 1000%, at least 10000%, or even higher; or elevation means the detection of the indicator from zero to its presence, and optionally, an increase within the aforementioned numerical range. In one embodiment, expression and binding to the cell surface are only seen in diseased tissues, while expression in healthy tissues is suppressed. According to this disclosure, diseases associated with CLDN6 expression and characterized by CLDN6 binding to its cell surface include neoplastic diseases, such as cancers, e.g., cancers involving CLDN6. Furthermore, according to this disclosure, neoplastic diseases (e.g., cancers) are preferably diseases in which tumor cells or cancer cells express CLDN6 and are characterized by CLDN6 binding to their cell surface. The methods provided in this disclosure can be used to treat or prevent various cancers involving CLDN6, whether malignant or benign, primary or secondary, early or late, or a combination of multiple cancers or types. The cancers can be solid cancers or hematologic malignancies.Examples of such cancers include lung cancer such as non-small cell lung cancer, bronchial cancers (e.g., squamous cell carcinoma, small cell carcinoma, large cell carcinoma, and adenocarcinoma), alveolar cell carcinoma, bronchial adenoma, chondromalacia (non-cancerous), and sarcoma (cancerous); cardiac cancers such as myxoma, fibroma, and rhabdomyosarcoma; bone cancers such as osteochondroma, condromas, chondroblastoma, chondromycinoid fibroma, osteoid osteoma, giant cell tumor, chondrosarcoma, multiple myeloma, osteosarcoma, fibrosarcoma, malignant fibrous histiocytoma, Ewing's tumor (Ewing's sarcoma), and reticulum cell sarcoma; and brain cancers such as gliomas (e.g., glioblastoma multiforme), anaplastic astrocytoma, and other neurogenic tumors. Cancers of the digestive system, such as colon cancer, leiomyoma, oligodendroglioma, medulloblastoma, chordoma, schwannoma, ependymoma, meningioma, pituitary adenoma, pineal tumor, osteoma, hemangioblastoma, craniopharyngioma, chordoma, germ cell tumor, teratoma, dermoid cyst, and hemangioma; cancers of the liver, such as hepatocellular adenoma, hemangioma, hepatocellular carcinoma, fibroblastic carcinoma, cholangiocarcinoma, hepatoblastoma, and angiosarcoma; kidney cancers, such as renal adenocarcinoma, renal cell carcinoma, adrenoidoma, and transitional cell carcinoma of the renal pelvis; bladder cancer; and hematologic malignancies, such as... Acute lymphoblastic leukemia, acute myeloid leukemia (myeloid, pleurodesis, myelomonocytic), chronic lymphocytic leukemia (e.g., Sezary syndrome and hairy cell leukemia), chronic myeloid lymphoma (myeloid, pleurodesis, granulocytic), Hodgkin lymphoma, non-Hodgkin lymphoma, B-cell lymphoma, mycosis fungoides, and myeloproliferative disorders (including myeloproliferative disorders such as polycythemia vera, myelofibrosis, thrombocytosis, and chronic myeloid leukemia); skin cancers such as basal cell carcinoma, squamous cell carcinoma, melanoma, Kaposi's sarcoma, and Paget's disease; head and neck cancer; and eye-related cancers. Cancers such as retinoblastoma and intraocular melanoma; male reproductive system cancers such as benign prostatic hyperplasia, prostate cancer, and testicular cancer (e.g., seminoma, teratoma, embryonal carcinoma, and choriocarcinoma); breast cancer; female reproductive system cancers such as uterine cancer (uterine carcinosarcoma, endometrial cancer), cervical cancer, ovarian cancer (ovarian cancer, ovarian teratoma), vulvar cancer, vaginal cancer, fallopian tube cancer, and hydatidiform mole; thyroid cancer (including papillary, follicular, anaplastic, or medullary carcinoma); pheochromocytoma (adrenal gland); non-cancerous growths of the parathyroid gland; pancreatic cancer; and hematologic cancers such as leukemia, myeloma, non-Hodgkin's lymphoma, and Hodgkin's lymphoma. In one specific implementation, the cancer is colon cancer. In some implementations, the disease associated with CLDN6 expression is cancer, preferably selected from the group consisting of ovarian cancer (e.g., ovarian adenocarcinoma and ovarian teratoma), lung cancer (e.g., small cell lung cancer and non-small cell lung cancer), gastric cancer, breast cancer, liver cancer, pancreatic cancer, skin cancer, malignant melanoma, head and neck cancer, sarcoma, bile duct cancer, bladder cancer, kidney cancer, colorectal cancer, small bowel cancer, placental choriocarcinoma, cervical cancer, testicular cancer (e.g., testicular teratoma and embryonal testicular cancer), and uterine cancer and their metastatic forms. In some implementations, the CLDN6 expression-associated disease is a fibrotic disease or a fibrosis-driven cancer, including fibrosis-related diseases, diseases manifesting as fibrosis, or fibrosis-related complications. In some implementations, the fibrotic disease is selected from fibrosis of the lungs, liver, colon, gallbladder, and stomach. In some embodiments, the fibrotic disease is selected from the group consisting of hepatitis, pulmonary fibrosis, liver fibrosis, cirrhosis, scleroderma, and biliary atresia. In some embodiments, the hepatitis includes non-alcoholic steatohepatitis (NASH). In some embodiments, the pulmonary fibrosis includes idiopathic pulmonary fibrosis. In some embodiments, the liver fibrosis includes alcohol- or drug-induced liver fibrosis and infection-induced liver fibrosis. According to this disclosure, the terms "fibrosis" and "fibrotic disease" refer to a pathological condition characterized by the excessive deposition of fibrous connective tissue in an organ or tissue. More specifically, fibrosis is a pathological process that includes persistent fibrotic scar formation and excessive production of extracellular matrix by connective tissue in response to tissue damage. Physiologically, deposits of connective tissue can destroy the structural systems and functions of an organ or tissue. The inventors evaluated the antibody's effects and efficacy in liver fibrosis models (such as long-term CDAA diet-induced liver fibrosis models, CC14-induced liver injury models, etc.) and found through immunohistochemical staining that the disclosed antibody can significantly reduce liver fibrosis. The inventors also observed the beneficial effects of the disclosed antibody on the treatment of biliary atresia in a mouse model of biliary atresia (such as an RRV-induced biliary atresia mouse model) by observing indicators such as mouse body weight, survival rate, degree of liver tissue damage and fibrosis, and cytokines closely related to fibrosis. Antibodies or their antigen-binding portions, antibody-drug conjugates, or drug compositions may be used alone as a monotherapy or in combination with chemotherapy or radiotherapy. Antibodies or their antigen-binding portions, antibody-drug conjugates, or drug compositions may be used in combination with immune checkpoint inhibitors (e.g., CTLA-4 inhibitors, PD-1 inhibitors, PD-L1 inhibitors), anticancer agents, antiproliferative agents, cytotoxic agents, chemotherapeutic agents, radiotherapy agents, antiangiogenic agents, and antimetastatic agents. Chemotherapy includes the administration of agents selected from: paclitaxel, cisplatin, carboplatin, their prodrugs, their salts, and combinations thereof. Some (non-limiting) examples of chemotherapeutic agents that can be combined with this application are: sorafenib, PEB, carboplatin (Paraplatin), cisplatin (Platinol, Platinol-AQ), crizotinib (Xalkori), cyclophosphamide (Cytoxan, Neosar), docetaxel (Taxotere), doxorubicin (Adriamycin), erlotinib (Tarceva), etoposide (VePesid), fluorouracil (5-FU), and gemcitabine (Gemzar). Imatinib mesylate (Gleevec), irinotecan (Camptosar), liposome-encapsulated doxorubicin (DOXIL), methotrexate (Folex, Mexate, Amethopterin), paclitaxel (Taxol, Abraxane), sorafenib (Nexavar), sunitinib (Sutent), topotecan (Hycamtin), trabectidin (Yondelis), vincristine (Oncovin, Vincasar PFS), and vinblastine (Velban). The term "metastasis" refers to the spread of cancer cells from their initial location to other parts of the body. The formation of metastasis is a highly complex process, relying on malignant cells detaching from the primary tumor, invading the extracellular matrix, penetrating the endothelial basement membrane to enter body cavities and blood vessels, and subsequently being transported via the bloodstream before infiltrating target organs. Ultimately, the growth of a new tumor at the target site depends on angiogenesis. Tumor metastasis often occurs even after the removal of the primary tumor because tumor cells or components may remain and develop metastatic potential. In one embodiment, the term "metastasis" according to this disclosure refers to "distant metastasis," which means metastasis distant from the primary tumor and the local lymph node system. The cells in secondary or metastatic tumors are similar to those in the primary tumor. This means that, for example, if ovarian cancer metastasizes to the liver, the secondary tumor is composed of abnormal ovarian cells (rather than abnormal liver cells), and the tumor in the liver is called metastatic ovarian cancer (rather than liver cancer). The terms "anticancer agent" or "antiproliferative agent" refer to any pharmaceutical agent that can be used to treat cell-proliferating conditions such as cancer, and include, but are not limited to, cytotoxic agents, cell inhibitors, anti-angiogenic agents, radiotherapy and radiotherapy agents, targeted anticancer agents, BRMs, therapeutic antibodies, cancer vaccines, cytokines, hormone therapy, radiotherapy, antimetastatic agents, and immunotherapy agents. It should be understood that, in selected embodiments as described above, such anticancer agents may comprise conjugates and may be bound to a disclosed site-specific antibody prior to administration. More specifically, in some embodiments, a selected anticancer agent is linked to an unpaired cysteine ​​residue of an engineered antibody to provide an engineered conjugate as described herein. Therefore, such engineered conjugates are explicitly considered within the scope of this disclosure. In other embodiments, the disclosed anticancer agent will be administered in combination with a site-specific conjugate comprising the various therapeutic agents described above. This disclosure also provides combinations of antibodies or their antigen-binding portions, antibody-pharmaceutical conjugates, or pharmaceutical compositions with radiotherapy (i.e., any mechanism for locally inducing DNA damage within tumor cells, such as gamma irradiation, X-rays, UV irradiation, microwaves, electron emission, etc.). Combination therapies using the targeted delivery of radioisotopes to tumor cells have also been considered, and the disclosed conjugates can be used in combination with targeted anticancer agents or other targeted agents. Typically, radiotherapy is administered in pulses over a period of approximately one to two weeks. Radiotherapy can be administered to subjects with head and neck cancer for approximately six to seven weeks. Optionally, radiotherapy can be administered as a single dose or as multiple sequential doses. Cancer surgery—the procedure of removing tumors—remains fundamental to cancer treatment at times. Surgery can be combined with other cancer treatments to remove any remaining tumor cells, such as with antibodies or their antigen-binding moieties, antibody-drug conjugates, or drug combinations. Combining surgical approaches with subsequent immunotherapy has repeatedly demonstrated to be a promising method. The effects or results of “effects”, “treatment” or “prevention” described in this disclosure include, but are not limited to, inhibiting tumor growth, reducing tumor size, preventing cancer recurrence and / or metastasis, and prolonging survival time. diagnosis This disclosure provides in vitro and in vivo methods for detecting, diagnosing, or monitoring proliferative disorders, as well as methods for screening cells from patients to identify tumor cells, including tumorigenic cells. Such methods include identifying individuals for treating cancer or monitoring cancer progression, including contacting a patient or a sample obtained from a patient (in vivo or in vitro) with an antibody described herein and detecting the presence or absence of the antibody in the sample, or the binding level, of a bound or free target molecule. In some embodiments, the antibody will comprise a detectable marker or reported molecule as described herein. In some aspects, this disclosure provides a method for diagnosing, detecting, or monitoring diseases associated with CLDN6 expression, comprising administering an effective dose of the antibody or its antigen-binding moiety, the nucleic acid molecule, the vector, the host cell, the conjugate, the antibody-drug conjugate, or the pharmaceutical composition or kit to a desired subject. In some aspects, this disclosure provides an antibody or its antigen-binding portion, the nucleic acid molecule, the vector, the host cell, the conjugate, the antibody-drug conjugate, or the pharmaceutical composition or kit in a method for diagnosing, detecting, or monitoring diseases associated with CLDN6 expression in a subject. In another aspect, this disclosure provides the use of the antibody or its antigen-binding portion, the nucleic acid molecule, the vector, the host cell, the conjugate, the antibody-drug conjugate, or the pharmaceutical composition or kit in the preparation of reagents for the diagnosis, detection, or monitoring of diseases characterized by CLDN6 (such as human CLDN6) expression or CLDN6 (such as human CLDN6) binding to its cell surface. In some implementations, the binding of an antibody to specific cells in a sample may indicate that the sample may contain tumorigenic cells, thereby suggesting that an individual with cancer can be effectively treated with the antibodies described herein. Samples can be analyzed using a variety of assays, such as radioimmunoassay, enzyme immunoassay (e.g., ELISA), competitive binding assay, fluorescence immunoassay, immunoblotting, Western blot analysis, and flow cytometry. Compatible in vivo diagnostic or diagnostic assays may include imaging or monitoring techniques known in the art, such as magnetic resonance imaging, computed tomography (e.g., CAT scan), positron emission tomography (e.g., PET scan), radiography, ultrasound, etc., as known to those skilled in the art. The methods described in this disclosure for detecting or monitoring CLDN6 expression or the level of CLDN6-expressing cells in vitro can also be used for non-diagnostic purposes. Preferred subjects include mammals, such as people / patients in need. The subject's samples are blood, excrement (urine or feces), oral or nasal secretions, or bronchoalveolar lavage fluid, tissue fluid, sweat, or extracts thereof. Drug packaging and reagent kits Pharmaceutical packages and kits are also provided in one or more containers containing one or more doses of an antibody or its antigen-binding moiety, an antibody-drug conjugate, or a pharmaceutical composition. In some embodiments, a unit dose is provided, wherein the unit dose contains a predetermined amount of a composition comprising, for example, an antibody or its antigen-binding moiety, or an antibody-drug conjugate, with or without one or more other reagents. For other embodiments, such a unit dose is supplied in a single-use, pre-filled syringe. In other embodiments, the composition contained in the unit dose may contain saline, sucrose, or the like; buffers, such as phosphates; and / or formulated within a stable and effective pH range. Alternatively, in some embodiments, the conjugate composition may be provided as a lyophilized powder, which can be reconstituted upon addition of a suitable liquid (e.g., sterile water or a saline solution). In some preferred embodiments, the composition contains one or more substances that inhibit protein aggregation, including but not limited to sucrose and arginine. Any label on or associated with the container indicates that the packaged conjugate or composition is intended for the treatment of selected oncological conditions. This disclosure also provides a kit for generating single- or multiple-dose administration units of site-specific conjugates and optionally one or more anticancer agents. The kit includes a container and a label or packaging insert on or associated with the container. Suitable containers include, for example, bottles, vials, syringes, etc. The container can be formed of various materials, such as glass or plastic, and contains a pharmaceutically effective amount of the disclosed conjugate or non-conjugate form of the conjugate. In other preferred embodiments, the container includes a sterile access port (e.g., the container may be an intravenous solution bag or a vial with a stopper that can be punctured by a hypodermic needle). Such kits typically contain a pharmaceutically acceptable formulation of the engineered conjugate in a suitable container and optionally contain one or more anticancer agents in the same or different containers. The kit may also contain other pharmaceutically acceptable formulations for diagnostic or combination therapy. For example, in addition to the antibodies or their antigen-binding moieties or antibody-drug conjugates disclosed herein, such kits may contain any one or more anticancer agents, such as immune checkpoint inhibitors; chemotherapeutic agents or radiotherapy agents; antiangiogenic agents; antimetastatic agents; anticancer agents or targeted anticancer agents; antiproliferative agents; cytotoxic agents; and / or other anticancer agents. More specifically, the kit may have a single container containing the disclosed antibody or its antigen-binding moiety, antibody-drug conjugate, or pharmaceutical composition, with or without additional components, or they may have different containers for each desired reagent. In cases where a combination therapeutic agent for conjugation is provided, a single solution may be premixed in molar equivalents or in a manner where one component is more than another. Alternatively, the conjugate and any optional anticancer agent in the kit may be stored separately in different containers prior to administration to the patient. The kit may also include a second / third container for containing sterile, pharmaceutically acceptable buffers or other diluents such as sterile water for injection (BWFI), phosphate-buffered saline (PBS), Ringer's solution, and glucose solution. When the reagent kit components are provided as one or more liquid solutions, the liquid solutions are preferably aqueous solutions, particularly sterile aqueous solutions or saline solutions. However, the reagent kit components may also be provided as dry powders. When reagents or components are provided in dry powder form, the powder can be reconstituted by adding a suitable solvent. It is conceivable that the solvent may also be provided in a separate container. As briefly described above, the kit may also contain a tool for administering an antibody or its antigen-binding moiety, an antibody-drug conjugate, or a pharmaceutical composition and any optional components to a patient, such as one or more needles, IV bags (intravenous injection bags), or syringes, or even eye drops, pipettes, or other similar devices by which the preparation can be injected or introduced into an animal or applied to a diseased area of ​​the body. The kits disclosed herein typically also include devices for containing vials or the like, and other tightly sealed components for commercial sale, such as injection or blow-molded plastic containers, in which the desired vials and other devices are placed and held. This application is accompanied by a sequence listing containing numerous nucleic acid and amino acid sequences. Tables A, B, C, D, E, F, G, H, and I below provide an overview of the included sequences. The illustrative antibody disclosed herein is an anti-CLDN6 monoclonal antibody. Table A. CDR amino acid sequence Table B. Amino acid sequence of the variable region Table C. CDR amino acid sequence of the improved antibody Table D. Amino acid sequence of the variable region of the improved antibody Table E. IgG1 heavy chain constant region, IgG1 light chain constant region, and signal peptide used in the full-length sequence. Table F. Various full-length sequences of 51C10H4 as examples Table G. CDR amino acid sequence of the improved antibody Table H. Variable region sequence of improved antibodies Table I. Full-length sequences of PiH1004, PiH2012, and PiH2012-1 as examples Example The present disclosure, which is generally described herein, will be more readily understood by referring to the following embodiments, which are provided by way of example and are not intended to limit the present disclosure. These embodiments are not intended to represent all or only the experiments conducted below. Example 1. Preparation of materials 1.1 Generation of Immunogens The immunogens used in this disclosure include plasmid DNA and stable cell lines. 1.1.1 Preparation of Gene Immunization Bullets. The DNA sequence of human CLDN6 was cloned into the plasmid pCDH-CMV-MCS-EF1-Puro. The plasmid pCDH-CMV-MCS-EF1-Pur-CLDN6 was transformed into the cloning strain Stbl3. Plasmid amplification was performed at 30℃, and plasmid DNA was extracted using conventional methods. Gene immunotherapy bullets were prepared using Bio-rad gold particles and the pCDH-CMV-MCS-EF1-Pur-CLDN6 plasmid. Each gene immunotherapy bullet contained approximately 3 μg of plasmid DNA. 1.1.2 The DNA sequence of human CLDN6 was cloned into plasmid pcDNA3.4, and the target gene plasmid was transfected into CHO-K1 cells. The stable cell line CHO-K1-CLDN6 expressing the target protein CLDN6 was constructed through screening. 1.2 Production of the benchmark antibody In this embodiment, a baseline antibody, IMAB027, was used as a positive control. It was formed by linking the variable region sequence of mAb206-LCC (see SEQ ID NO: 47 and SEQ ID NO: 67 in Table B) with the human IgG1 constant region sequence (see SEQ ID NO: 84 and SEQ ID NO: 85 in Table E) according to US Patent US14 / 117118 (CN103748112B), and is designated IMAB027. 1.3 Establishing stable cell lines Human CLDN6, mouse CLDN6, monkey CLDN6, human CLDN3, human CLDN4, and human CLDN9 were overexpressed in HEK293T cells and CHO-K1 cells using lentiviral infection. After 72 hours of cell infection, cells were cultured with antibiotics for 2-4 weeks. Single clones were selected, expanded, and cryopreserved, resulting in eight cell lines: HEK293T-CLDN6, HEK293T-CLDN9, HEK293T-CLDN3, HEK293T-CLDN4, CHO-K1-CLDN9, CHO-K1-CLDN6, CHO-K1-Mouse CLDN6, and CHO-K1-Cyno CLDN6. These were used for subsequent animal immunization and selection. Example 2. Antibody production 2.1 Immunity and Cell Fusion 2.1.1 Immunity On days 0 and 20, Balb / c mice (Beijing Vital River Laboratory Animal Technology Co., Ltd.) were immunized intraperitoneally with 3 μg of plasmid DNA containing CLDN6. On days 40, 54, 63, and 83, CHO-K1 cells transfected with pcDNA3.4-CLDN6 (CHO-K1-CLDN6, concentration 5 × 10⁻⁶) were then introduced. 6 Balb / c mice were immunized with 0.5 mL of serum venous blood (0.5 mL / ml) via intraperitoneal injection. Blood was collected from the submandibular vein of immunized mice on days 47 and 70 according to the immunization schedule for serum titer determination. Serum titers were identified using the FACS method, and animals with higher serum titers were selected for spleen cell fusion. Three days before spleen cell fusion, mice exhibiting the highest antibody titers received a booster immunization. 2.1.2 Cell Fusion Spleens were extracted from mice that had undergone multiple immunizations and homogenized to produce single-cell suspensions. Simultaneously, single-cell suspensions of myeloma cells (SP2 / 0) were prepared, with approximately 8 × 10⁸ cells per cell. 7 Spleen cells were electrofused with SP2 / 0 mouse myeloma cells. The fused cells were resuspended in HAT medium (DMEM / 10% FBS medium containing hypoxantin, aminopterin, and thymidin) containing hybridoma cell selectors and transferred to 96-well cell culture plates. The cells were incubated at 37°C in 5.5% CO2. After 6-7 days of incubation, fused hybridoma cells capable of both expressing antibodies and proliferating indefinitely in vitro were obtained; these were termed hybridoma blast cells. The binding affinity of the antibodies expressed in the hybridoma cell supernatant to CLDN6 was detected using FACS. 2.2 Screening of hybridoma supernatant Hybridoma supernatants were screened by flow cytometry. Using HEK293T-CLDN6 cells overexpressing CLDN6, hybridoma supernatants specifically binding to CLDN6 were identified by FACS analysis. Negative screening was performed using HEK293T-CLDN9, HEK293T-CLDN3, HEK293T-CLDN4, and HEK293T cells. For hybridoma supernatants that produced the target clone, antibody-secreting hybridomas were re-inoculated into DMEM / 10% FBS medium for secondary screening to obtain monoclonal hybridomas. 2.3 Hybridoma Sequencing After screening, hybridoma monoclonal cells that specifically bind to CLDN6-overexpressing cells and naturally CLDN6-expressing tumor cells were obtained and sequenced. NGS sequencing was used to obtain the variable region of the hybridoma monoclonal cells. NGS sequencing: RNA is extracted from hybridoma cells, reverse transcribed into cDNA, and IgG is amplified using antibody primers. A unique marker sequence (index sequence) is added to each hybridoma antibody gene. All gene samples are mixed and sequenced using an NGS sequencer. Bioinformatics analysis of the sequencing results is used to separate the IgG sequences, and then the cell lines from which these sequences originated are reconstructed using the index sequences. 2.4 Chimeric antibodies The chimerism of antibodies is achieved by linking the variable regions of the mouse antibody heavy and light chains to the constant regions of the human heavy and light chains (e.g., as described by Kraus et al. in Methods in Molecular Biology series, Recombinant antibodies for cancer therapy ISBN-0-89603-918-8, or refer to section of CN 111875703 A).

[0313] part). In this disclosure, the variable regions of the heavy and light chains of a murine antibody (see Table B) are linked to the constant regions of the heavy and light chains of human IgG1 (see Table E) to obtain the full-length sequence of a chimeric antibody (e.g., Table F). Those skilled in the art will understand that the constant regions of the heavy chains used to generate the chimeric antibody can be IgG1, IgG3, IgG4, IgG2, IgA, IgD, or IgM. The full-length sequence of the antibody disclosed herein can be obtained by linking the corresponding variable regions and the constant regions of human IgG, such as the IgG1, IgG2, IgG3, and IgG4 constant regions. Specifically, as an example, the heavy chain variable region of each antibody (including chimeric antibodies, humanized antibodies, or modified antibodies) is linked to the IgG1 heavy chain constant region to obtain the full-length heavy chain sequence of the antibody. Furthermore, a signal peptide can be linked to the other end of the heavy chain variable region to obtain a full-length sequence containing a signal peptide. As an example, the light chain variable region of each antibody (including chimeric antibodies, humanized antibodies, or modified antibodies) is linked to the IgG1 light chain constant region to obtain the full-length light chain sequence of the antibody. Furthermore, a signal peptide can be linked to the other end of the light chain variable region to obtain a full-length sequence containing a signal peptide. The amino acid sequences of the IgG1 heavy chain constant region, IgG1 light chain constant region, and signal peptide described in this disclosure are shown in Table E. As an example, the full-length heavy chain sequence of 51C10H4, the full-length heavy chain sequence containing the signal peptide, the full-length light chain sequence of 51C10H4, and the full-length light chain sequence containing the signal peptide are described in Table F. Combining the construction of the full-length sequences described above with the examples in Table F, the full-length sequences of all chimeric antibodies, modified antibodies / modified antibodies, and humanized antibodies described in this disclosure can be obtained. Expi293F cells were cultured normally 24 hours before transfection. At transfection, Expi293F cells were diluted to 3 × 10⁻⁶. 6 Add preheated OptiPRO medium to two centrifuge tubes at a concentration of / mL. Add the heavy chain plasmid and light chain plasmid to one centrifuge tube, and the transfection reagent to the other centrifuge tube. Mix immediately at room temperature to obtain the complex. Incubate at room temperature for 1-2 min. Add the complex to normally cultured Expi293F cells and continue culturing at 37°C with 8% CO2 for 18-22 hours. Then add transfection enhancer and cell culture medium to the cells. Then continue culturing the cells at 32°C with 5% CO2. On the fourth day after transfection, add cell culture medium to the cells and continue culturing the cells at 32°C with 5% CO2. On the ninth day after transfection, harvest the supernatant from the culture flask and perform affinity purification using a protein A column. The disclosed CLDN6 antibody, as a four-transmembrane protein, possesses four transmembrane hydrophobic regions and two extracellular regions. Its recombinant protein is extremely difficult to express, thus posing challenges to the preparation of suitable antigens for immunization and screening against CLDN6 antibodies. Furthermore, due to the high amino acid sequence homology between CLDN6 and its family members such as CLDN9, CLDN3, and CLDN4, screening for monoclonal antibodies that specifically target CLDN6 or do not bind to at least one member of its family is considerably difficult, requiring extensive screening. Specifically, this disclosure screens at least 14,400 clones and conducts three rounds of screening, including screening of maternal clone supernatant, screening of subclones, and screening of chimeric antibodies, ultimately obtaining chimeric antibodies of CLDN6 that satisfy multiple satisfactory properties as described in this disclosure, such as CLDN6 binding, tumor cell binding, ADCC characteristics, CDC characteristics, and endocytosis, as well as humanized antibodies that are modified / improved and / or screened based on these properties. 2.5 Humanized Antibodies To reduce the immunogenicity of the antibody in humans, a humanized anti-CLDN6 antibody was produced using the sequence of the screened anti-CLDN6 antibody of this disclosure. The CDR region of a mouse anti-CLDN6 antibody was combined with a human framework region (e.g., human immunoglobulin) to form the humanized anti-CLDN6 antibody of this disclosure. This humanized antibody retains its ability to bind to human CLDN6 as well as its ability to bind to monkey CLDN6. To prepare humanized antibodies, mouse CDR regions can be inserted into human frame sequences using methods known in the art (see Winter's US 5,225,539; Queen et al.'s US 5,530,101; US ​​5,585,089; US 5,693,762; and Lo, Benny, KC, editor in Antibody Engineering: Methods and Protocols, volume 248, Human Press, New Jersey, 2004). In this disclosure, the full-length sequence of the humanized antibody can be obtained by linking the variable region sequence of the humanized antibody in Table B to the IgG1 constant region in Table E. For example, the heavy chain variable region of the humanized antibody in Table B can be linked to the IgG1 heavy chain constant region in Table E, and the light chain variable region of the humanized antibody in Table B can be linked to the IgG1 light chain constant region in Table E, respectively. Optionally, the signal peptide sequence shown in Table E can also be linked to the variable region. For example, as described above, the full-length sequence of a humanized antibody can be obtained by obtaining the full-length sequence with a chimeric antibody, using the humanized antibodies in Table B (e.g., PiH1001, PiH1002, PiH1003, PiH1004, PiH1005, PiH1006, PiH1007, PiH1008, PiH2001, PiH2004, PiH2005, PiH2006, PiH2007, PiH2008, PiH2009, PiH2010, PiH2011, PiH201). 2) The variable region is linked to the IgG1 constant region in Table E. Specifically, the heavy chain variable region of humanized antibodies (e.g., PiH1001, PiH1002, PiH1003, PiH1004, PiH1005, PiH1006, PiH1007, PiH1008, PiH2001, PiH2004, PiH2005, PiH2006, PiH2007, PiH2008, PiH2009, PiH2010, PiH2011, PiH2012) is linked to the IgG1 heavy chain constant region. By linking specific regions, the full-length heavy chain sequence of the humanized antibody is obtained. For example, as shown in Table G, the full-length heavy chain sequences of humanized antibodies PiH1004 and PiH2012 are obtained. Furthermore, the signal peptide in Table E can be linked to the other end of the variable region of the heavy chain to obtain a full-length sequence containing the signal peptide. Specifically, humanized antibodies (e.g., PiH1001, PiH1002, PiH1003, PiH1004, PiH1005, PiH1006, PiH1007, PiH1008, PiH2 ... The light chain variable regions of (H2004, PiH2005, PiH2006, PiH2007, PiH2008, PiH2009, PiH2010, PiH2011, PiH2012) are linked to the IgG1 light chain constant regions in Table E to obtain the full-length light chain sequence of the humanized antibody. As an example, the full-length light chain sequences of humanized antibodies PiH1004 and PiH2012 are obtained as shown in Table G. Furthermore, the signal peptide in Table E can be linked to the other end of the light chain variable region to obtain the full-length sequence containing the signal peptide. 2.6 Antibody Improvement Antibody improvement methods include recombination, conserved amino acid substitution, glycosylation variants, Fc region mutations, or cysteine ​​engineering to obtain improved antibodies with excellent / satisfactory CLDN6 binding properties and tumor therapeutic / inhibitory properties. (1) Reorganization Specifically, as an example, this disclosure combines the heavy chain of 51C10H4 with the light chain of 54B5A7 to generate a novel, improved chimeric monoclonal antibody, RecA101. Similarly, this disclosure can also combine the heavy chains of PiH1001, PiH1002, PiH1003, PiH1004, PiH1005, PiH1006, PiH1007, and PiH1008 with the light chains of PiH2001, PiH2004, PiH2005, PiH2006, PiH2007, PiH2008, PiH2009, PiH2010, PiH2011, and PiH2012 to generate novel humanized antibodies. (2) Conservative amino acid substitution For example, conserved amino acid substitutions can be made to the sequences in this disclosure, including chimeric antibody sequences or humanized antibody sequences. For instance, when the CDR region of the sequence in this disclosure contains a deamidation hotspot NG (such as the CDR2 region of 20A3-2A7, the CDR2 region of 51C10H4, the CDR2 region of RecA101, or the CDR2 region of PiH1001-PiH1008), this site can be mutated in various ways. The mutation schemes are diverse; for example, G in NG can be mutated to A / S / D / Q, or... In NG, N is mutated to S / Q / A to remove amino acids that pose a risk of deamidation; for example, when the CDR region of the sequence in this disclosure contains DG (such as the CDR3 region of 51C10H4, the CDR3 region of RecA101, and the CDR3 region of PiH1001-PiH1008), this site is mutated in various ways. The mutation schemes are diverse. For example, D in DG can be mutated to E / S / G, or G can be mutated to A / S / D / Q to reduce the risk of reduced antigen binding affinity caused by isomerization. Specifically, as an example, this disclosure mutates the deamidation hotspot NG of CDR2 in 20A3-2A7 or its humanized antibody, changing G in NG to A to obtain the improved antibody 20A3-M1 (composed of the heavy chain shown in SEQ ID NO: 109 and the light chain shown in SEQ ID NO: 121) or an improved antibody of its humanized antibody. It should be understood that other mutations can be performed on this NG site; the G mutation in NG can be termed S / D / Q, and the N mutation in NG can be changed to S / Q / A to obtain other improved antibodies or improved antibodies of its humanized antibody. Specifically, as an example, this disclosure mutates the deamidation hotspot NG of CDR2 in 20A3-2A7 or its humanized antibody, changing G in NG to Q to obtain the improved antibody 20A3-M2 (composed of the heavy chain shown in SEQ ID NO: 110 and the light chain shown in SEQ ID NO: 121) or an improved antibody of its humanized antibody. It should be understood that this NG site can also undergo other mutations; the G mutation in NG can be termed S / D / A, and the N mutation in NG can be called S / Q / A, to obtain other improved antibodies or improved antibodies of its humanized antibody. Specifically, as an example, this disclosure mutates the deamidation hotspot NG of CDR2 of 51C10H4 or its humanized antibodies (e.g., PiH1001, PiH1002, PiH1003, PiH1004, PiH1005, PiH1006, PiH1007, PiH1008), and mutates G in NG to A to obtain the improved antibody 51C10-M1 (composed of the heavy chain shown in SEQ ID NO: 111 sequence and the light chain shown in SEQ ID NO: 88 sequence) or the corresponding improved antibodies of its humanized antibodies (e.g., PiH1001-M1, PiH1002-M1, PiH1003-M1, PiH1004-M1, PiH1005-M1, PiH1006-M1, PiH1007-M1, PiH1008-M1). Specifically, as an example and explanation, this disclosure mutates the deamidation hotspot NG of CDR2 in the heavy chain of PiH1004, changing G in NG to A, to obtain the improved antibody PiH1004-M1 (composed of the heavy chain shown in SEQ ID NO: 115 and the light chain shown in SEQ ID NO: 122). It should be understood that other mutations can be performed on this NG site; for example, G in NG can be mutated to S / D / Q, and N in NG can be mutated to S / Q / A to obtain other improved antibodies. Specifically, as an example, this disclosure mutates the deamidation hotspot NG of CDR2 of 51C10H4 or its humanized antibodies (e.g., PiH1001, PiH1002, PiH1003, PiH1004, PiH1005, PiH1006, PiH1007, PiH1008), mutating N in NG to Q, to obtain the improved antibody 51C10-M2 (composed of the heavy chain shown in SEQ ID NO: 112 and the light chain shown in SEQ ID NO: 88) or the corresponding improved antibodies of its humanized antibodies (e.g., PiH1001-M2, PiH1002-M2, PiH1003-M2, PiH1004-M2, PiH1005-M2, PiH1006-M2, PiH1007-M2, PiH1008-M2). Specifically, as an example, this disclosure mutates the isomerization site DG in the CDR3 region of 51C10H4 or its humanized antibodies (e.g., PiH1001, PiH1002, PiH1003, PiH1004, PiH1005, PiH1006, PiH1007, PiH1008) to obtain an improved antibody 51C10-M3 (composed of the heavy chain shown in SEQ ID NO: 113 and the light chain shown in SEQ ID NO: 88). It should be understood that DG at this site can also undergo other mutations, such as mutating D to E / S / G or G to A / S / D / Q, to obtain other improved antibodies or corresponding improved antibodies of its humanized antibodies (e.g., PiH1001-M3, PiH1002-M3, PiH1003-M3, PiH1004-M3, PiH1005-M3, PiH1006-M3, PiH1007-M3, PiH1008-M3). Specifically, as an example, this disclosure mutates the isomerization site DG in the CDR3 region of 51C10H4 or its humanized antibodies (e.g., PiH1001, PiH1002, PiH1003, PiH1004, PiH1005, PiH1006, PiH1007, PiH1008), changing D in DG to E, to obtain the improved antibody 51C10-M4 (composed of the heavy chain shown in SEQ ID NO: 114 and the light chain shown in SEQ ID NO: 88) or the corresponding improved antibodies of its humanized antibodies (e.g., PiH1001-M4, PiH1002-M4, PiH1003-M4, PiH1004-M4, PiH1005-M4, PiH1006-M4, PiH1007-M4, PiH1008-M4). It should be understood that, in this manner, the same or similar mutations can be performed on the CDR2 of antibodies containing deamide hotspots NG, such as CDR2 of 15H2D4, CDR2 of 54B5A7, CDR2 of RecA101, or CDR2 of humanized antibodies of these antibodies (e.g., PiH1001, PiH1002, PiH1003, PiH1004, PiH1005, PiH1006, PiH1007, PiH1008), for example, mutating G in NG to A / S / D / Q or mutating N to S / Q / A, to obtain corresponding improved antibodies. It should be understood that, in this manner, the same or similar mutations can be performed in the CDR3 of antibodies containing the isomerization site DG, such as CDR2 of 58G3C7, CDR3 of 54B5A7, CDR3 of RecA101, CDR3 of 51C10-M1, CDR3 of 51C10-M2, or in the CDR3 of humanized antibodies of these antibodies (e.g., PiH1001, PiH1002, PiH1003, PiH1004, PiH1005, PiH1006, PiH1007, PiH1008), to mutate G in DG to A / S / D / Q or to mutate D to E / S / G, thereby obtaining the corresponding improved antibodies. It should be understood that the two sites mentioned above, such as the deamide hotspot NG and the isomerization site DG, can be mutated simultaneously, and other hotspot regions disclosed in the prior art for improving antibody properties can also be mutated in the antibodies of this disclosure. It should be understood that the site mutations for improving antibodies in this disclosure can not only be based on chimeric antibodies as shown above, but also, in the same or similar manner, site mutations can be performed in the CDR region of humanized antibodies to obtain corresponding improved humanized antibodies. (3) Fc region mutation In practice, there is a need to reduce the ADCC effect caused by IgG1 subclass. Existing technologies widely employ mutations in the Fc region of IgG1, including the "LALA" (L234A+L235A) mutation, which can reduce the binding affinity of the antibody's Fc region to FcγR by 100-fold. The Fc mutant obtained in this application may result in an even lower binding affinity to FcγR, thus more significantly reducing the ADCC effect. The "Fc region mutation" in this application can be performed in all antibodies in this application. In some specific embodiments, this includes using chimeric antibodies from Table B (e.g., 51C10H4, 54B5A7, 20A3-2A7, etc.) or humanized antibodies (e.g., PiH1001, PiH1002, PiH1003, PiH1004, PiH1005, PiH1006, PiH1007, PiH1008, PiH2001, PiH2004, PiH2005, PiH2006, PiH2007, P...). The Fc mutant is obtained by mutating iH2008, PiH2009, PiH2010, PiH2011, PiH2012) or the improved antibody (20A3-M1, 20A3-M2, 51C10-M1) in Table D or any other antibody in this disclosure into the “LALA” (L234A+L235A) region of IgG1. For example, PiH2012-1 is obtained by mutating PiH2012 into the “LALA” region as shown in Table G. (4) Mutations in other CDR regions Specifically, as an example, the present invention mutates the deamidation hotspot NG of CDR2 in the heavy chain of PiH1004, and mutates G in NG to A, to obtain the improved antibody PiH1004-M1 (composed of the heavy chain shown in SEQ ID NO: 167 sequence and the light chain shown in SEQ ID NO: 174 sequence). Specifically, as an example, the present invention mutates the V of CDR2 in the heavy chain of PiH1004 to A / I / L, thereby obtaining the corresponding improved antibody (composed of the heavy chain variable region shown in SEQ ID NO: 105 and the light chain variable region shown in SEQ ID NO: 69, the heavy chain variable region shown in SEQ ID NO: 106 and the light chain variable region shown in SEQ ID NO: 69, and the heavy chain variable region shown in SEQ ID NO: 107 and the light chain variable region shown in SEQ ID NO: 69). Specifically, as an example, the present invention mutates the T of CDR2 in the heavy chain of PiH1004 to S, thereby obtaining a corresponding improved antibody (composed of the heavy chain variable region shown in SEQ ID NO: 108 and the light chain variable region shown in SEQ ID NO: 69). Specifically, as an example, the present invention mutates the L of CDR3 in the heavy chain of PiH1004 to V, thereby obtaining a corresponding improved antibody (composed of the heavy chain variable region shown in SEQ ID NO: 109 and the light chain variable region shown in SEQ ID NO: 69). Specifically, as an example, the present invention mutates the Y of CDR3 in the heavy chain of PiH1004 to F, thereby obtaining a corresponding improved antibody (composed of the heavy chain variable region shown in SEQ ID NO: 110 and the light chain variable region shown in SEQ ID NO: 69). Specifically, as an example, the present invention mutates the V of CDR3 in the heavy chain of PiH1004 to S, thereby obtaining a corresponding improved antibody (composed of the heavy chain variable region shown in SEQ ID NO: 111 and the light chain variable region shown in SEQ ID NO: 69). Specifically, as an example, the present invention mutates the D of CDR1 in the light chain of PiH1004 to E, thereby obtaining a corresponding improved antibody (composed of the heavy chain variable region shown in SEQ ID NO: 52 and the light chain variable region shown in SEQ ID NO: 112). Specifically, as an example, the present invention mutates the I of CDR1 in the light chain of PiH1004 to V, thereby obtaining a corresponding improved antibody (composed of the heavy chain variable region shown in SEQ ID NO: 52 and the light chain variable region shown in SEQ ID NO: 113). Specifically, as an example, the present invention mutates the N of CDR1 in the light chain of PiH1004 to Q, thereby obtaining a corresponding improved antibody (composed of the heavy chain variable region shown in SEQ ID NO: 52 and the light chain variable region shown in SEQ ID NO: 114). Specifically, as an example, the present invention mutates the A of CDR2 in the light chain of PiH1004 to G, thereby obtaining a corresponding improved antibody (composed of the heavy chain variable region shown in SEQ ID NO: 52 and the light chain variable region shown in SEQ ID NO: 115). Specifically, as an example, the present invention mutates the T of CDR3 in the light chain of PiH1004 to S, thereby obtaining a corresponding improved antibody (composed of the heavy chain variable region shown in SEQ ID NO: 52 and the light chain variable region shown in SEQ ID NO: 116). Specifically, as an example, the present invention mutates the W of CDR3 in the light chain of PiH1004 to a hydrophobic aliphatic amino acid G, thereby obtaining a corresponding improved antibody (composed of the heavy chain variable region shown in SEQ ID NO: 52 and the light chain variable region shown in SEQ ID NO: 117). Specifically, as an example, the present invention mutates the S of CDR3 in the light chain of PiH1004, mutating the uncharged polar amino acid S into a positively charged polar amino acid G, to obtain a corresponding improved antibody (composed of the heavy chain variable region shown in SEQ ID NO: 52 and the light chain variable region shown in SEQ ID NO: 118). Specifically, as an example, the present invention also includes the following improved CDR sequences in Tables J, K and L, which can be combined by those skilled in the art to form specific antibodies according to actual needs. Table J. Heavy chain CDR sequence of improved antibody Table K improves the light chain CDR sequence of the antibody. Table L. CDR amino acid sequence of the improved antibody It should be understood that, regarding the CDR region of the mutant antibody shown in Table L, those skilled in the art can not only improve the PiH1004 antibody, but also make the same or similar improvements to other sequences in this application such as 51C10H4, 54B5A7, RecA101, PiH1001-PiH1008, PiH2001-PiH2012, etc. It should be understood that when other antibodies in this disclosure contain the above-mentioned sites, the above-mentioned mutation methods can also be performed in other antibodies in this disclosure. Experiments have confirmed that the improved antibody disclosed herein does not significantly alter the antibody's ability to bind to CLDN6-expressing cells, and exhibits binding properties to a variety of tumor cells. 2.7 Antibody Purification Expi293F cells containing the antibody sequence plasmid were cultured in shake flasks and purified using Protein A Magnetic Beads (GenScript Biotech, L00695). Elution was performed using 0.1M citrate and sodium citrate buffer (pH 3.0). Neutralization was achieved with Tris-HCl buffer (pH 9.0). After dialyzing in PBS (pH 7.4), the antibody concentration and purity were determined using Nanodrop 2000 (Thermo), with an extinction coefficient of 1.43. The antibody concentration reached 3 mg / mL. The antibody concentration was verified to be between 0.5 mg / mL and 3 mg / mL by denaturing and non-denaturing polyacrylamide gel electrophoresis (SDS-PAGE) and size exclusion high-performance liquid chromatography (SEC-HPLC). Example 3. Determination of antibody binding ability to CLDN6 To detect the binding ability of chimeric or humanized antibodies to CLDN6, the CLDN6-expressing cell line HEK293T-CLDN6 and the CLDN6-non-expressing negative control cells HEK293T were washed three times with PBS. 1×10⁻⁶ cells were added to each well of a 96-well plate. 5 Each cell and 50 μL of the antibody solution were incubated at 4°C for 1 hour. Cells were then washed three times with PBS. Alexa 647-labeled anti-human IgG antibody was then used to bind to either a chimeric antibody or a humanized antibody bound to CLDN6, and the cells were incubated at 4°C for 45 minutes. Finally, the cells were washed three times with PBS, and the signal was read using FACS. The results are shown in Table 1. Table 1. FACS detection results of chimeric antibodies on HEK293T and HEK293T-CLDN6 Figures 1, 2, 3, 4, and 5 show the binding capacity of the chimeric antibody, the modified chimeric monoclonal antibody RecA101, and the humanized antibody on HEK293T-CLDN6, respectively, plotting the antibody concentration relative to the FACS signal (Geometric mean). The EC50 value (the antibody concentration that binds to half of the binding sites at equilibrium) was calculated using nonlinear regression, and the corresponding EC50 values ​​are shown in Tables 2, 3, 4, 5, and 6. Table 2. EC50 values ​​of partially chimeric antibodies on HEK293T-CLDN6 (unit: μg / mL) Table 3. EC50 values ​​of partially chimeric antibodies on HEK293T-CLDN6 (unit: μg / mL) Table 4. EC50 values ​​of the improved chimeric monoclonal antibody on HEK293T-CLDN6 (unit: μg / mL) Table 5. EC50 values ​​of humanized antibodies (PiH1001-PiH1008) on HEK293T-CLDN6 (unit: μg / mL) Table 6. EC50 values ​​of humanized antibodies (PiH2001-PiH2008) on HEK293T-CLDN6 (unit: μg / mL) The results above show that, compared to the unhumanized chimeric antibody 54B5A7, the binding activity of the humanized antibody was not substantially reduced. Furthermore, the chimeric antibody, improved chimeric monoclonal antibody, and humanized antibody obtained in this disclosure all exhibit excellent CLDN6 binding properties, with some chimeric antibodies showing significantly better binding properties than the baseline antibody IMAB027, especially under high concentration conditions. The inventors further discovered through experiments that the CLDN6 binding activity of PiH2012 is comparable to that of the unhumanized chimeric antibody 54B5A7 (not shown in the figure). Example 4. Determination of the binding affinity of chimeric antibodies and modified antibody RecA101 to CLDN3 / 4 / 9 Flow cytometry (FACS) was used to detect the specific binding of chimeric antibodies and modified antibodies RecA101, 20A3-M1, 20A3-M2, 51C10-M1, and the modified antibody PiH1004 in Table G (Table H) to cells expressing CLDN6, as well as their binding to cells expressing CLDN3, CLDN4, and CLDN9. Add 50 μL of the antibody to be tested to a 96-well plate, and add 1 × 10⁻⁶ μL of antibody to each well.5 Cells were incubated at 4°C for 1 hour. Cells were washed three times with PBS, and then incubated at 4°C for 45 minutes with chimeric or humanized antibodies bound to CLDN6 using Alexa 647-labeled anti-human IgG antibody. Finally, cells were washed three times with PBS, and signals were read using FACS. The binding ability at CLDN9 / CLDN3 / CLDN4 was analyzed based on the detection information. The results are shown in Figures 6-12. Meanwhile, Table 7 shows the FACS detection ratios of some chimeric antibodies 293T-CLDN6 and 293T-CLDN3 / 4 / 9, and Tables 8 and 9 show the FACS detection ratios of some improved antibodies on 293T-CLDN6 / 293T-CLDN9. Table 7. FACS detection results of partially chimeric antibodies on 293T-CLDN6 / 293T-CLDN3 / 4 / 9 (10 μg / mL) Table 8. FACS detection results of the improved antibody on 293T-CLDN6 / 293T-CLDN9 / HEK293T (10 μg / mL) Table 9. FACS detection results of the improved antibody on 293T-CLDN6 / 293T-CLDN9 / HEK293T (10 μg / mL) The results above show that the chimeric antibodies disclosed herein all exhibit significant CLDN6 binding specificity, which is significantly superior to that of the benchmark antibody IMAB027. Although some antibodies show binding signals on CLDN3, CLDN4, or CLDN9, their binding signals are significantly lower than those on CLDN6, sometimes by hundreds of times. For example, for antibodies with some CLDN9 binding ability, the CLDN6 / CLDN9 signal ratio of some antibodies reaches approximately 200 times, such as 54B5A7 and 51C10H4; while some antibodies, although exhibiting detectable CLDN9 binding ability, still have a CLDN6 / CLDN9 signal ratio of approximately 50 times, such as 58G3C7, 47D5D6, and 20A3-2A7. The improved antibodies disclosed herein, including 20A3-M1, 20A3-M2, 51C10-M1 and RecA101, also exhibit significant CLDN6 binding specificity. Compared with the control antibody IMAB027, 20A3-M1 and 20A3-M2, in particular, show significantly weaker CLDN9 binding. Figure 13 shows the results of the chimeric antibodies 51C10H4 and 54B5A7 binding to cell lines HEK293T-CLDN6, HEK293T-CLDN9, HEK293T-CLDN3, and HEK293T-CLDN4 at a concentration of 5 μg / mL. The results show that the chimeric antibodies 51C10H4 and 54B5A7 exhibit superior specificity for HEK293T-CLDN6 compared to IMAB027. Furthermore, these two chimeric antibodies show almost no binding to CLDN3 and CLDN4, while their binding to CLDN9 is hundreds of times weaker than their binding to CLDN6, thus maximizing therapeutic efficacy and minimizing systemic toxicity. The inventors further discovered that the binding affinity of humanized antibodies PiH1001-PiH1008 to CLDN3 / 4 / 9 is comparable to that of unhumanized 51C10H4, and the binding affinity of humanized antibodies PiH2001, PiH2004, PiH2005, PiH2006, PiH2007, PiH2008, PiH2009, PiH2010, PiH2011, and PiH2012 to CLDN3 / 4 / 9 is comparable to that of unhumanized 54B5A7. Figure 35 shows the binding affinity of the modified PiH1004 antibodies, such as PiH1004-VH-Mutation11-VL, PiH1004-VH-Mutation8-VL, PiH1004-VH-VL-Mutation2, PiH1004-VH-VL-Mutation3, PiH1004-VH-VL-Mutation4, PiH1004-VH-VL-Mutation6, and PiH1004-VH-VL-Mutation7, to CLDN6 in Table G (Table H). It can be seen that compared with the antibody PiH1004, these site-directed mutation modified antibodies did not reduce their binding affinity to CLDN6, and in some site-directed mutations, the binding affinity of the modified antibodies to CLDN6 was actually increased. In addition, this disclosure also tested the binding ability of the antibodies in Table K to CLDN6. Compared with the unmutated antibody (PiH1004), the mutations of these improved antibodies did not reduce their binding ability to CLDN6 (not shown in the figure). Example 5. Determination of mouse and monkey cross-reactivity of antibodies As described above, flow cytometry (FACS) was used to detect the binding of chimeric or humanized antibodies to cells overexpressing mouse CLDN6 and cells expressing monkey CLDN6. Figures 14, 15, 16, and 17 show the binding results of the chimeric antibody with cells overexpressing CLDN6 in mice and monkeys, respectively. Figures 18, 19, 20, and 21 show the binding results of the humanized antibody with cells overexpressing CLDN6 in mice and monkeys, respectively. The corresponding EC50 values ​​are shown in Table 10. Table 10: EC50 values ​​of chimeric antibodies binding to cells overexpressing CLDN6 in mice and monkeys (unit: μg / mL) As can be seen from the results in Table 10 and Figures 14 to 17, the chimeric antibody disclosed herein has good binding ability with cells overexpressing CLDN6 in mice and monkeys. As can be seen from the results in Figures 18 to 21, compared with the unhumanized antibody, the humanized antibody of this disclosure has a significantly reduced ability to bind to CLDN6 cells overexpressing mice. In particular, the humanized antibody of 54B5A7 hardly binds to CLDN6 cells overexpressing mice. This indicates that the humanization modification of this disclosure has successfully reduced / avoided cross-reactivity between species. Example 6. Determination of antibody binding ability and inhibitory effect on tumor cells Flow cytometry (FACS) was used to detect the specific binding of chimeric antibodies to tumor cells, and the EC50 value was calculated to evaluate the inhibitory effect of the antibodies on tumor cells. Add 50 μL of the antibody to be tested to a 96-well plate, and add 1 × 10⁻⁶ μL of antibody to each well. 5 Cells were incubated at 4°C for 1 hour. Cells were washed three times with PBS. Alexa 647-labeled anti-human IgG antibodies were then used to bind to the test antibodies that had bound the corresponding tumor cells, and the cells were incubated at 4°C for 45 minutes. Finally, cells were washed three times with PBS, and signals were read using FACS. The binding ability of the test antibodies to various tumor cells was analyzed based on the detection information. The results are shown in Figures 22-31 and 36-37. Figures 22-27 show the binding ability of chimeric antibodies, modified chimeric monoclonal antibodies RecA101, and humanized antibodies against HepG2 (human hepatocellular carcinoma cells). Figures 28-31 show the binding ability of chimeric antibodies and humanized antibodies against PA-1 (human ovarian teratoma cells). Figure 36 shows the binding ability of PiH1004 and PiH2012 with human ovarian cancer cells OVCA429. Figure 37 shows the binding ability of PiH1004 and PiH2012 with human gastric cancer cells MKN7. Tables 11 to 15 also present the EC50 values ​​of these antibodies on tumor cells calculated based on Figures 22 to 31. Table 16 shows the FACS detection results of the improved antibody against HepG2 at a concentration of 5 μg / ml. Table 11. EC50 values ​​of partially chimeric antibodies against tumor cells (unit: μg / mL) Table 12. EC50 values ​​of partially chimeric antibodies against tumor cells (unit: μg / mL) Table 13. EC50 values ​​of humanized antibodies (unit: μg / mL) Table 14. EC50 values ​​of humanized antibodies (unit: μg / mL) Table 15. EC50 values ​​of humanized antibodies (unit: μg / mL) Table 16. FACS detection results of the improved antibody (antibody concentration: 5 μg / ml) As the results above show, firstly, the chimeric and humanized antibodies disclosed herein bind significantly to tumor cells PA-1 and HepG2 with very low EC50 values, and exhibit significant inhibitory / killing activity against tumor cells in vitro. The inhibitory / killing activity of some chimeric antibodies is comparable to or better than that of the benchmark antibody IMAB027, suggesting the therapeutic potential of the antibodies disclosed herein for ovarian and liver cancer. Furthermore, as shown in Table 16, the binding effect on HepG2 tumor cells is comparable between the humanized improved antibody and the original antibody, indicating that the improvements / mutations disclosed herein did not lead to a decrease in tumor-inhibiting activity. The various antibodies disclosed herein have also shown good efficacy in other tumor cells. As verified in Figure 24, the recombined chimeric monoclonal antibody RecA101 exhibits superior binding ability to positive antibodies on HepG2 cells. The improved antibody 20A3-M1 disclosed herein has also shown binding activity with a variety of tumor cells, such as human ovarian cancer cells OVCAR3, human ovarian teratoma cells PA-1, and liver cancer cells HepG2, demonstrating significant binding properties. Similar effects have been observed with other improved antibodies 51C10-M1, 51C10-M2, 51C10-M3, and 51C10-M4. Furthermore, published literature has revealed high expression of CLDN6 in various cancer tissues and corresponding tumor cells, including testicular cancer, ovarian cancer, lung cancer, gastric cancer, breast cancer, liver cancer, pancreatic cancer, skin cancer, malignant melanoma, head and neck cancer, sarcoma, cholangiocarcinoma, renal cell carcinoma, and uterine cancer. Therefore, the chimeric antibody, humanized antibody, and improved antibody disclosed herein are also expected to have therapeutic effects on these tumors. Example 7. Antibody-dependent cytotoxicity (ADCC) method Effector cells (NK92 / CD16A-VV) were collected and resuspended in ADCC buffer (99% MEMα, nucleoside, phenol red-free + 1% fetal bovine serum). Target cells (CHO-K1-CLDN6) were collected and resuspended in ADCC buffer. Working solutions for the test and control samples were prepared using ADCC buffer. The target cell density was adjusted with ADCC buffer, and the target cell suspension was transferred to 96-well plates. The test, control, or ADCC buffer solution was transferred to the corresponding wells of the 96-well plate. The plate was incubated at room temperature for 30 minutes. Based on the E / T ratio (effector cell to target cell ratio), the effector cell density was adjusted with ADCC buffer, and the effector cell suspension was transferred to the corresponding wells of the 96-well plate. The plate was incubated in a cell culture incubator (37°C / 5% CO2) for 6 hours. After incubation, the 96-well plate was removed, centrifuged, and the supernatant was carefully aspirated and transferred to a new 96-well plate. Transfer the LDH detection working solution (lactose dehydrogenase detection working solution) to the corresponding wells of a new 96-well plate and develop the color at room temperature. Read the OD value on a microplate reader at a detection wavelength of 492 nm and a reference wavelength of 650 nm. The effector cells used in this experiment were NK92 / CD16A-VV, and the target cells were CHO-K1-CLDN6. Under an effector-to-target cell ratio of 3:1, the test samples (54B5A7 and 51C10H4) and human IgG1 were serially diluted and co-incubated with the corresponding target cells for 6 hours. The percentage of target cell lysis was then measured. The results are shown in Figure 32 and Table 17. The data in the figures represent the percentage of target cell lysis (Mean ± SEM). Table 17. Fitting parameters for ADCC dose-response experiment As can be seen from Table 17 and Figure 32, under the current experimental conditions, chimeric antibodies 54B5A7 and 51C10H4 showed significant ADCC effects on CHO-K1-CLDN6 cells, and both were able to effectively induce the killing of CLDN6-expressing tumor cells. In contrast, the negative control (human IgG1) did not show any ADCC effect on CHO-K1-Claudin6 cells. Example 8. Complement-dependent cytotoxicity (CDC) method Target cells (CHO-K1-CLDN6) were cultured in complete medium in a cell culture incubator at 37°C / 5% CO2. The effector molecule was 5% NHSC (normal human serum complement), with a maximum concentration of 50 μg / mL and a dilution factor of 5 times. Eight concentration points were obtained. Collect target cells and resuspend them in CDC buffer. Prepare the test and control samples using CDC buffer, adjust the target cell density, and transfer the cell suspension to 384-well plates. Transfer the working solutions of the control / test samples to the corresponding wells of the 384-well plates and incubate the plates at room temperature for 30 minutes. Prepare the NHSC working solution and transfer it to the corresponding wells of the 384-well plates. Incubate the plates in a cell culture incubator (37°C / 5% CO2) for 4 hours. After incubation, remove the plates and add Cell... (Promega, catalog number G7573) working solution, incubated at room temperature for 10 minutes, and the chemiluminescence value was read using an ELISA reader. Raw data from the CDC experiments were exported via the Phera Star FSX system and analyzed using Microsoft Office Excel 2016 and GraphPad Prism 6 software. Positive controls, test samples, and human IgG1 were serially diluted under 5% NHSC conditions and co-incubated with the corresponding target cells (CHO-K1-CLDN6) for 4 hours. The percentage of target cell lysis was then measured. The results are shown in Figure 33 and Table 18. Data in the figures represent the percentage of target cell lysis (Mean ± SEM). Table 18. Fitting parameters for CDC dose-response experiment As can be seen from Figure 33 and Table 18, both chimeric antibodies 54B5A7 and 51C10H4 can effectively mediate the CDC effect on CHO-K1-CLDN6 cells, while the negative control (human IgG1) cannot mediate the CDC effect on CHO-K1-CLDN6 cells. Example 9. Internalization Test This disclosure uses DT3C recombinant protein (Huamei Biotechnology, catalog number: CSB-EP360556CQR1) to determine antibody internalization and immunotoxin activity. DT3C is a protein genetically engineered by fusing the catalytic region of diphtheria toxin (DT) and the antibody-binding region of streptococcal protein G. DT3C specifically binds to the Fc region of the antibody; if ingested into cells, it induces cell death by inhibiting protein synthesis. Using this system, the cell-killing effects induced by antibody internalization and immunotoxins can be observed simultaneously. PA-1 cells were cultured, and cells in the logarithmic growth phase were seeded at a density of 500 cells / well in 40 μL into 384-well plates and incubated overnight at 37°C with 5% CO2. Chimeric antibody, baseline antibody, and negative control human IgG1 were mixed with DT3C protein at a 1:2 ratio and incubated at room temperature for 30 minutes to form mAb-DT3C conjugates. These conjugates were added to 384-well plates and incubated at 37°C with 5% CO2 for 3 days. Add 20 μL of CellTiter-Glo assay kit (CTG) reagent (Promega, catalog number: G7573) to each well, incubate at room temperature for 30 minutes, and record the luminescence value using an Envision 2105 microplate reader. The results are shown in Figure 34. As shown in Figure 34, the DT3C conjugates of 54B5A7, 20A3-2A7, and 51C10H4 at a concentration of 4.2 nM achieved an inhibition rate of over 90% against PA-1 cells, comparable to the baseline antibody IMAB027. This indicates that the chimeric antibodies 54B5A7, 20A3-2A7, and 51C10H4 have a significant internalization effect on PA-1 cells, which is an important step in ADC activation. Example 10: Preparation of ADC molecules In this embodiment, the disclosed ADC (No. 3-7 in Table 21) and the comparative ADC (No. 1-2 in Table 21) were synthesized according to the antibody, adapter, and drug (toxin) composition listed in Table 21. The structures of the antibodies, adapters, and toxins used are as described above. PiH1004 and PiH2012-1 are both humanized antibodies, as shown in Table G. AB3-7 refers to the humanized antibody AB3-7 described in Table 8 of Chinese invention patent application CN114174340A, which is formed by linking the variable region sequence of antibody 3-7 (see SEQ ID NO: 387 and SEQ ID NO: 389 in Table D) of CN114174340A with the constant region sequence of human IgG1 (see SEQ ID NO: 84 and SEQ ID NO: 85 in Table E). 1. Preparation of antibody-MMAE 1.1 Preparation of PiH1004-VcMMAE antibody-drug conjugate Take 1.767 mL of PiH1004 antibody (28.3 mg / mL), add 3.094 mL of His / HCl solution (pH 6.0) and mix well, then add 0.139 mL of TCEP (tris(2-carboxyethyl)phosphine) solution and mix well. The mixture was stirred at 25°C for 120 minutes. Eight times the amount of MC-VC-PAB-MMAE dissolved in dimethyl sulfoxide was added to the above solution system, and the mixture was stirred at 25°C for 120 minutes. After the reaction was completed, 0.347 mL of cysteine ​​was added to terminate the reaction. The mixture was placed at 25°C for 30 minutes, and then 0.278 mL of DHAA solution was added. The mixture was stirred at 25°C for 120 minutes. Finally, a 2 mL spin desalting column with a MWCO of 40 kDa was used to remove residual small molecule drugs from the antibody-drug conjugate, yielding a pure product of MC-VC-PAB-MMAE conjugated with antibody PiH1004, named PiH1004-VcMMAE, or simply PiH1004-MMAE. The DAR value of PiH1004-MMAE was determined by size exclusion chromatography-tandem mass spectrometry (SEC-MS), and the results are shown in Table 19 and Figure 38. Table 19. Detection results of PiH1004-MMAE 1.2. Preparation of PiH2012-1-VcMMAE antibody-drug conjugate Take 2.367 mL of PiH2012-1 antibody (16.9 mg / mL), add 1.524 mL of His / HCl solution (pH 6.0), mix well, then add 0.110 mL of TCEP (tris(2-carboxyethyl)phosphine) solution and mix well. The mixture was stirred at 25°C for 120 minutes. Eight times the amount of MC-VC-PAB-MMAE dissolved in dimethyl sulfoxide was added to the above solution system, and the mixture was stirred at 25°C for 120 minutes. After the reaction was completed, 0.274 mL of cysteine ​​was added to terminate the reaction. The mixture was placed at 25°C for 30 minutes, and then 0.219 mL of DHAA solution was added. The mixture was stirred at 25°C for 120 minutes. Finally, a 2 mL spin desalting column with a MWCO of 40 kDa was used to remove residual small molecule drugs from the antibody-drug conjugate, yielding a pure product of MC-VC-PAB-MMAE conjugated with antibody PiH2012-1, named PiH2012-1-VcMMAE, or PiH2012-1-MMAE for short. 1.3. Preparation of AB3-7-VcMMAE antibody-drug conjugate Take 1.556 mL of AB3-7 antibody (16.9 mg / mL), add 2.334 mL of His / HCl solution (pH 6.0), mix well, then add 0.110 mL of TCEP (tris(2-carboxyethyl)phosphine) solution and mix well. The mixture was stirred at 25°C for 120 minutes. Eight times the amount of MC-VC-PAB-MMAE dissolved in dimethyl sulfoxide was added to the above solution system, and the mixture was stirred at 25°C for 120 minutes. After the reaction was completed, 0.274 mL of cysteine ​​was added to terminate the reaction. The mixture was placed at 25°C for 30 minutes, and then 0.219 mL of DHAA solution was added. The mixture was stirred at 25°C for 120 minutes. Finally, a 2 mL spin desalting column with a MWCO of 40 kDa was used to remove residual small molecule drugs from the antibody-drug conjugate, yielding a pure product of MC-VC-PAB-MMAE conjugated with antibody AB3-7, named AB3-7-VcMMAE, or AB3-7-MMAE for short. 2. Preparation of antibody-DXd 2.1. Preparation of PiH1004-GGFG-DXd antibody-drug conjugate Take 0.568 mL of PiH1004 antibody (44 mg / mL), add 1.411 mL of a solution containing 20 mM His / HCl (pH 6.0), mix well, then add 10 mM TCEP (tris(2-carboxyethyl)phosphine) solution and mix well. Incubate at 25°C for 120 minutes. Add 15 times the amount of Deruxtecan dissolved in dimethyl sulfoxide to the above solution system, mix well, and incubate at 25°C for 120 minutes. Finally, add 173.6 μL of 10 mM cysteine ​​to terminate the reaction. Finally, use a 2 mL spin desalting column with a MWCO of 40 kDa to remove residual small molecule drug from the antibody-drug conjugate, obtaining a pure Deruxtecan-PiH1004 antibody conjugate, named PiH1004-GGFG-DXd, or simply PiH1004-DXd. The DAR value of PiH1004-DXd was determined by size exclusion chromatography-tandem mass spectrometry (SEC-MS), and the results are shown in Table 20 and Figure 39. Table 20. Detection results of PiH1004-DXd 2.2. Preparation of PiH2012-1-GGFG-DXd antibody-drug conjugate Take 0.799 mL of PiH2012-1 antibody (31.3 mg / mL), add 1.359 mL of a solution containing 20 mM His / HCl (pH 6.0), mix well, then add 10 mM TCEP (tris(2-carboxyethyl)phosphine) solution and mix well. Incubate at 25°C for 120 minutes. Add 15 times the amount of Deruxtecan dissolved in dimethyl sulfoxide to the above solution system, mix well, and incubate at 25°C for 120 minutes. Finally, add 171.2 μL of 10 mM cysteine ​​to terminate the reaction. Finally, use a 2 mL spin desalting column with a MWCO of 40 kDa to remove residual small molecule drug from the antibody-drug conjugate, obtaining a pure product of Deruxtecan conjugated with antibody PiH2012-1, named PiH2012-1-GGFG-DXd, abbreviated as PiH2012-1-DXd. 2.3. Preparation of AB3-7-GGFG-DXd antibody-drug conjugate Take 0.633 mL of AB3-7 antibody (39.5 mg / mL), add 1.524 mL of a solution containing 20 mM His / HCl (pH 6.0), mix well, then add 10 mM TCEP (tris(2-carboxyethyl)phosphine) solution and mix well. Incubate at 25°C for 120 minutes. Add 15 times the amount of Deruxtecan dissolved in dimethyl sulfoxide to the above solution system, mix well, and incubate at 25°C for 120 minutes. Finally, add 171.2 μL of 10 mM cysteine ​​to terminate the reaction. Finally, use a 2 mL spin desalting column with a MWCO of 40 kDa to remove residual small molecule drug from the antibody-drug conjugate, obtaining the pure Deruxtecan-AB3-7 conjugate product, named AB3-7-GGFG-DXd, or AB3-7-DXd for short. 3. Preparation of antibody-DM1 3.1. Preparation of PiH1004-VcDM1 antibody-drug conjugate Take 0.455 mL of PiH1004 antibody (44.0 mg / mL), add 1.462 mL of a solution containing 20 mM His / HCl (pH 6.0), mix well, then add 3 times the amount of 5 mM TCEP (tris(2-carboxyethyl)phosphine) solution and mix well. Incubate at 25 °C for 120 minutes, then add 6 times the amount of MC-VC-PAB-DM1 dissolved in dimethyl sulfoxide to the above solution system, mix well, and incubate at 25 °C for 120 minutes. After completion, add 138.9 μL of 10 mM N-acetylcysteine ​​to terminate the reaction, and after 30 minutes, add 111.1 μL of 10 mM dehydroascorbic acid. After being placed at 25°C for 120 minutes, residual small molecule drugs in the antibody-drug conjugate were removed using a 2 mL spin desalting column with a MWCO of 40 kDa, yielding a pure product of MC-VC-PAB-DM1 conjugated with antibody PiH1004, named PiH1004-Vc-DM1, or simply PiH1004-DM1. The purity of the synthesized ADC, as well as the average coupling rate and drug distribution (DAR) value, are listed in Table 21. Table 21. Molecular composition and determination of ADC Example 11: ADC Molecular Flow Cytometry Detection Flow cytometry (FACS) was used to detect the binding of ADC molecules to PA-1 cells (human ovarian teratoma cells) and HepG2 cells (human liver cancer cells). The FACS method was as follows: PA-1 cells or HepG2 cells were washed three times with PBS. 1×10⁻⁶ ppm of ADC molecules was added to each well of a 96-well plate. 5 Each cell and 50 μL of the antibody solution were incubated at 4°C for 1 hour. Cells were then washed three times with PBS, and incubated at 4°C for 45 minutes with Alexa647-labeled anti-human IgG antibody combined with either a chimeric antibody or a humanized antibody bound to CLDN6. Finally, cells were washed three times with PBS, and signals were read using flow cytometry. Results in PA-1 and HepG2 cells are shown in Figures 40-41 and Tables 22-23, respectively. Table 22. EC50 values ​​of ADC molecules binding to PA-1 cells (unit: μg / mL) As shown in Figure 40 and Table 22, the affinity of the toxin-conjugated ADC molecule in this disclosure for PA-1 cells is slightly lower than that of the naked antibody molecule, but it can still effectively bind to PA-1 cells. In contrast, as shown in Figure 40D, the AB3-7 antibody of the comparative example binds weakly to PA-1 cells, and its ADC binding affinity is reduced more significantly. Table 23. EC50 values ​​of ADC molecules binding to HepG2 cells (unit: μg / mL) As shown in Figure 41 and Table 23, the affinity of the toxin-conjugated ADC molecule in this disclosure for HepG2 cells is close to that of the naked antibody molecule. In contrast, as shown in Figure 41D, the AB3-7 antibody and its ADC of the comparative example bind weakly to HepG2 cells. Example 12: In vitro efficacy of ADC molecules (cell killing assay) To test the efficacy of the antibody-drug conjugate, in vitro cell killing assays were performed in the following tumor cell models. The in vitro efficacy of the ADC molecule prepared in Example 11 was evaluated in PA-1 (human ovarian teratoma cells), OVCA429 (human ovarian cancer cells), Huh7 (human liver cancer cells), MKN7 (human gastric cancer cells), and HEK293T-CLDN6 cells. The cytotoxicity assay was performed as follows: 3000–5000 cells were seeded into each well of a 96-well plate. After culturing at 37°C for 24 hours, the drug was diluted with the appropriate culture medium, and different concentrations (0–5 μM) of the drug (ADC) were added to the 96-well plates. After treatment with the drug for 72–144 hours, the culture supernatant was discarded, and 100 μL of medium containing 10% CCK-8 was added. The plates were then incubated at 37°C with 5% CO2 for 1–4 hours. The OD values ​​of each well at 450 nm were measured using a microplate reader. The data were analyzed, proliferation inhibition curves were plotted, and the IC50 value was calculated. Table 24. IC50 values ​​of ADC molecules on the cytotoxic effect of PA-1 (unit: nM) Results for PA-1 (human ovarian teratoma cells) cells highly expressing CLDN6 are listed in Figure 42 and Table 24. As shown in the figures, the ADCs conjugated with DM1 and MMAE showed comparable cytotoxicity against PA-1 cells and were superior to the AB3-7 ADC in the comparative example. These results demonstrate that the antibody-drug conjugates disclosed herein exhibit strong cytotoxic activity in the CLDN6-highly expressing PA-1 cell line. Table 25. IC50 values ​​of ADC molecules for cytotoxicity against OVCA429 (unit: nM) The results for OVCA429 (human ovarian cancer cells) cells with high CLDN6 expression are shown in Figure 43 and Table 25. As can be seen from the figures, the conjugates of MMAE and DXd exhibited stronger cytotoxic effects on OVCA429 cells, exceeding those of the comparative example AB3-7ADC. These results demonstrate that the antibody-drug conjugates disclosed herein possess strong cytotoxic activity in the CLDN6-high expression-positive OVCA429 cell line. Table 26. IC50 values ​​of ADC molecules for cytotoxicity against Huh7 (unit: nM) Results for Huh7 (human hepatocellular carcinoma cells) with moderate to low CLDN6 expression are shown in Figure 44 and Table 26. As can be seen from the figures, the killing effect of MMAE conjugate was higher than that of DM1 or DXd conjugate, and higher than that of the comparative example AB3-7ADC at the same toxin level. The results show that the antibody-drug conjugate of this disclosure has cytotoxic activity in the Huh7 cell line with moderate to low CLDN6 expression. Table 27. IC50 values ​​of ADC molecules for cytotoxicity against MKN7 (unit: nM) Results for MKN7 cells (human gastric cancer cells) with moderate CLDN6 expression are shown in Figure 45 and Table 27. As can be seen from the figures, the cytotoxic effect of the antibody-drug conjugate of this disclosure is superior to that of the comparative example AB3-7ADC. The results show that the antibody-drug conjugate of this disclosure has cytotoxic activity in the MKN7 cell line with moderate CLDN6 expression. Table 28. IC50 values ​​of ADC molecules for cytotoxicity against HEK293T-CLDN6 (unit: nM) The results for targeting HEK293T-CLDN6 cells with high CLDN6 expression are shown in Figure 46 and Table 28. As can be seen from the figures, conjugation with MMAE, DXd, or DM1 resulted in stronger cytotoxic activity against HEK293T-CLDN6 cells, exceeding that of the comparative example AB3-7ADC. These results demonstrate that the antibody-drug conjugates disclosed herein exhibit strong cytotoxic activity in the CLDN6-positive HEK293T-CLDN6 cell line. Considering the cell lines tested above, it can be found that the antibodies conjugated with the three linker-toxins disclosed in this disclosure all have cytotoxic effects, with the conjugation of MMAE showing the best cytotoxic effect. Further experiments confirmed that the antibodies conjugated with other linker-toxins (e.g., MC-GGFG-MMAE, MC-VC-PAB-MMAF, MC-GGFG-MMAF, MC-VC-PAB-DXd, MC-GGFG-DM1, CL2A-SN38) in this disclosure also have similar cytotoxic effects on the aforementioned cell lines (data not shown). Among the ADCs disclosed in this disclosure, PiH2012-1-MMAE showed better overall performance. An exception was observed in HepG2 cells, where MMAE had a lower IC50 than DXd and acted faster, but DXd exhibited a higher inhibitory rate against HepG2. Example 13: In vivo efficacy of ADC molecules (1) In vivo pharmacodynamics of ADC molecules in the CDX model To test the antitumor effects of the anti-CLDN6 antibody ADC drug, in vivo efficacy studies were conducted in the following mouse tumor models. The constructed tumor models were CDX models (cell line-derived xenograft tumor models), including: PA-1 (human ovarian teratoma cells) tumor model, OV90 (human ovarian cancer cells) tumor model, and HepG2 (human liver cancer cells) tumor model. The tumor model creation method is as follows: PA-1 (human ovarian teratoma cell) tumor model: 1.0 × 10 7 PA-1 cells (50% matrix gel) were subcutaneously injected into the right posterior abdomen of 5-6 week old female Balb / c athymic nude mice. The tumor was 100-200 mm in size. 3 When the average size is reached, tumor-bearing mice (n=6) are randomly assigned to the following drug administration groups. OV90 (human ovarian cancer cells) tumor model: 5.0 × 10 6 One OV90 cell (50% matrix gel) was subcutaneously injected into the right posterior abdomen of 5-6 week old female Balb / c athymic nude mice. When the tumor reached approximately 100-200 mm... 3 When the average size is reached, tumor-bearing mice (n=6) are randomly assigned to the following drug administration groups. HepG2 (human liver cancer cell) tumor model: 5.0 × 10 6 One HepG2 cell (50% Matrigel) was subcutaneously injected into the right posterior abdomen of 5-6 week old female Balb / c athymic nude mice. When the tumor reached approximately 100-200 mm... 3 When the average size is reached, tumor-bearing mice (n=5) are randomly assigned to the following drug administration groups. Dosing will be administered according to the experimental requirements, with the administration method and cycle being iv, QW×3W. The methods for detecting tumor volume are as follows: The tumor volume was measured using vernier calipers twice a week, taking both the long and short diameters. The volume was calculated using the formula: Tumor volume = 0.5 × long diameter × short diameter 2 . The weight measurement method is as follows: Vaccination, grouping (before the first dose), administration twice a week during the administration period, and weighing the animals before euthanasia. PA-1: Figure 47B shows the tumor volume inhibition effect of the ADC molecule in the mouse PA-1 CDX model, and Figure 47A shows the corresponding tumor volume changes. Figure 47C shows the tumor volume changes of some molecules. As can be seen from the figures, both DXd and MMAE conjugates exhibit significant tumor-suppressive effects in the PA-1 mouse model, and these effects are dose-dependent. At the same dose, the tumor-suppressive effect of DXd conjugate (PA-1) is stronger, and the tumor-suppressive effect of PiH1004-DXd (1 mg / kg) is stronger than that of AB3-7-DXd (1 mg / kg). The results show that the antibody-drug conjugates disclosed herein have significant tumor-suppressive effects in the PA-1 mouse CDX model. OV90: The tumor volume changes of the ADC molecule in the OV90 CDX model of mice are shown in Figures 48A-48C, and the tumor volume inhibition photograph is shown in Figure 48D. The changes in mouse body weight are shown in Figure 49. As shown in Figure 48, the conjugation of DXd and MMAE both have significant antitumor effects in the OV90 mouse model, and these effects are dose-dependent. At the same dose, PiH1004-MMAE has a stronger inhibitory effect on OV90 xenograft tumors than AB3-7-MMAE (P<0.05). At the same dose, the antitumor effect of the disclosed molecules PiH1004 and PiH2012-1 conjugated with DXd is stronger than that of the control molecule AB3-7 conjugated with DXd. As shown in Figure 49, the antibody drug conjugated with DXd has no adverse effect on mouse body weight. The results show that the antibody drug conjugate of this disclosure has a significant antitumor effect in the OV90 mouse CDX model, and no side effects were observed. The antibody molecule of this disclosure conjugated with DXd and MMAE has a more significant antitumor effect than the control molecule. HepG2: Figure 50 shows the tumor volume reduction effect of the ADC molecule in the mouse HepG2 CDX model, and Figure 51 shows the mouse body weight reduction effect. As shown in Figure 50, the DXd conjugate exhibits a significant, dose-dependent antitumor effect in the HepG2 mouse model. As shown in Figure 51, compared to the control solvent, the low-dose ADC molecule had no effect on mouse body weight, while the medium- and high-dose ADC molecule resulted in increased body weight in mice 21 days after administration compared to the low-dose group and the solvent control group. It is believed that the medium- and high-dose groups may have a better tumor-suppressive effect, thus improving the cachexia caused by tumors and contributing to the increase in mouse body weight. The results show that the antibody-drug conjugate disclosed in this paper has a significant antitumor effect in the HepG2 mouse CDX model, and no side effects were observed. (2) In vivo efficacy of ADC molecules in the PDX model An ovarian cancer PDX model (patient-derived allogeneic tumor model) was constructed in mice, and the drugs were administered as shown in Table 29. Table 29. Administration Methods Record and analyze the changes in tumor volume and body weight of each group of tumor-bearing mice. The tumor volume inhibition rate (TGI) is calculated as follows: TGI(%)=[1-(Ti-T0) / (Vi-V0)]×100% Where: Ti: mean tumor volume in the treatment group on day i of drug administration; T0: mean tumor volume in the treatment group on day 0 of drug administration; Vi: mean tumor volume in the solvent control group on day i of drug administration; V0: mean tumor volume in the solvent control group on day 0 of drug administration. The tumor volume change curves of each group of tumor-bearing mice are shown in Figure 52. After 42 days of drug administration, the tumor inhibition rate (TGI) was calculated. From Figure 52 and the calculation, it can be seen that the TGI of the PiH2012-1-DXd (2mg / kg) group reached 93.8%, which was much greater than the 63.6% of the AB3-7-MMAE (2mg / kg) group. Compared with the tumor volume of the Vehicle group, the PiH-2012-1-DXd (2mg / kg) group had an extremely significant statistical difference (P<0.001), while the AB3-7-MMAE (2mg / kg) group had a significant statistical difference (P<0.01). The tumor growth rate (TGI) of the PiH1004-MMAE (2 mg / kg) group was comparable to that of the AB3-7-MMAE (2 mg / kg) group; compared with the tumor volume of the Vehicle group, both the PiH1004-MMAE (2 mg / kg) group and the AB3-7-MMAE (2 mg / kg) group showed statistically significant differences (P < 0.01). Furthermore, the TGI calculated after administration of PiH1004-DXd at doses of 1 mg / kg, 2 mg / kg, and 4 mg / kg (not shown in the figure) confirmed that the antitumor effect of the antibody-drug conjugate PiH1004-DXd disclosed herein is dose-dependent. As can be seen from Figure 53, the weight fluctuations of the animals in each group were small, indicating that the antibody drug did not produce significant toxic side effects on the animals and had good safety. The results showed that the antibody-drug conjugates disclosed herein had significant antitumor effects and no side effects were observed. Some antibody-drug conjugates showed superior antitumor activity compared to the control ADC molecule AB3-7-MMAE. By incorporating references The full contents of every patent and scientific document mentioned in this article are incorporated herein by reference for all purposes. Equivalence This disclosure may be embodied in other specific ways without departing from its spirit or essential characteristics. Therefore, the above embodiments should be considered illustrative in all cases and not as limiting of the invention described herein. Consequently, the scope of this disclosure is defined by the appended claims rather than by the foregoing description and is intended to be encompassed therein by all variations within the equivalent meaning and scope of the claims.

Claims

1. An antibody-drug conjugate, comprising: Anti-CLDN6 antibody or its antigen-binding moiety, and One or more pharmaceutical portions, said pharmaceutical portions being directly or via a linker (preferably covalently linked) to the anti-CLDN6 antibody or its antigen-binding portion, wherein The anti-CLDN6 antibody or its antigen-binding moiety includes a heavy chain variable region and a light chain variable region. The anti-CLDN6 antibody comprises: (1)CDRH1, which contains the sequence X1YNMH or is composed of the sequence, where X1 is selected from D or S; (2) CDRH2, which contains the sequence YX1X2PX3X4X5X6TX7YNQKFKG or is composed of the sequence, where X1 is selected from V or I, X2 is selected from N or Y, X3 is selected from N or G, X4 is selected from N or Q or S or A, X5 is selected from A or G or D or Q or S, X6 is selected from A or G, and X7 is selected from S or N; (3) CDRH3, which contains the sequence WX1X2YVYYYGX3DY or SEQ ID NO: 23 or is composed of it, X1 is selected from D or E or S or G, X2 is selected from A or G or S or D or Q, and X3 is selected from L or M; (4) CDRL1, which contains or consists of the sequence SEQ ID NO: 27 or SEQ ID NO: 29; (5) CDRL2, which contains or consists of the sequence SEQ ID NO: 30 or SEQ ID NO: 31; and (6) CDRL3, which contains or consists of the sequence QQYWX1TPYT or SEQ ID NO: 40, X 1 is selected from S or N; Or the anti-CLDN6 antibody may contain: (1) CDRH1, which contains or consists of SEQ ID NO: 5; (2) CDRH2, which contains or consists of SEQ ID NO: 12, or contains or consists of the sequence YX1NPNNGAX2X3YNQKFKG, where X1 is selected from A, I, L or V, X2 is selected from S or T, and X3 is selected from S or N; preferably, CDRH2 contains or consists of the sequence SEQ ID NO: 12, 91, 92, 93, 94, 119, 120, 121, 122, 123, 124 or 125; (3) CDRH3, which contains or consists of SEQ ID NO: 20, or contains the sequence WDGYX1YYYGX2DX3 or consists of the sequence, wherein X1 is selected from V or s, X2 is selected from V, L or M, and X3 is selected from Y or F; preferably, CDRH3 contains or consists of the sequence SEQ ID NO: 20, 95, 96, 97, 126, 127, 128, 129, 130, or 131; (4) CDRL1, which contains or is composed of the sequence sEQ ID NO: 27, or contains or is composed of the sequence KASX1HX2NX3WLA, wherein X1 is selected from E or D, X2 is selected from I or V, and X3 is selected from H or Q; preferably, CDRL1 contains or is composed of SEQ ID NO: 27, 98, 99, 100, 132, 133, 134, or 135; (5) CDRL2, which contains or consists of SEQ ID NO: 31, or which contains or consists of SEQ ID NO: 101; and (6) CDRL3, which comprises or is composed of SEQ ID NO: 37, or comprises or is composed of QQYX1X2TPYX3, wherein X1 is selected from W or G, X2 is selected from S, H or N, and X3 is selected from S or T; preferably, CDRL3 comprises or is composed of SEQ ID NO: 37, 102, 103, 104, 136, 137, 138, 139, 140, 141 or 142; Or the anti-CLDN6 antibody may contain: (1) CDRH1, which contains the sequence SYX1IX2 or is composed of the sequence, wherein X1 is selected from N or G and X2 is selected from H or S; (2) CDRH2, which contains or consists of the sequence X1IYPX2X3GX4TX5X6NEX7FKG, wherein X1 is selected from Y or E, X2 is selected from G or R, X3 is selected from N or S, X4 is selected from G or N, X5 is selected from K or Y, X6 is selected from Y or H, and X7 is selected from R or K. (3) CDRH3, which contains the sequence SEQ ID NO: 16 or SEQ ID NO: 19; (4) CDRL1, which contains the sequence SEQ ID NO: 24 or SEQ ID NO: 26, or is composed of SEQ ID NO: 24 or SEQ ID NO: 26; (5) CDRL2, which contains the sequence X1X2SNLX3S or is composed of the sequence, wherein X1 is selected from L or G, X2 is selected from A or T, and X3 is selected from E or A; and (6) CDRL3, which contains the sequence SEQ ID NO: 34 or SEQ ID NO: 179, or is composed of SEQ ID NO: 34 or SEQ ID NO: 179; Or the anti-CLDN6 antibody may contain: (1) CDRH1, which contains or consists of the sequence X1YX2MS, wherein X1 is selected from S or N and X2 is selected from G or A; (2) CDRH2, which contains the sequence TISX1GGSYTX2YPDX3X4KG or is composed of the sequence, wherein X1 is selected from S or D, X2 is selected from Y or S, X3 is selected from S or N, and X4 is selected from V or I; (3) CDRH3, which contains the sequence SEQ ID NO: 17 or SEQ ID NO: 18, or is composed of SEQ ID NO: 17 or SEQ ID NO: 18; (4) CDRL1, which contains the sequence SEQ ID NO: 25 or consists of SEQ ID NO: 25; (5) CDRL2, which contains the sequence X1X2TSLET or is composed of the sequence, wherein X1 is selected from G or A, and X2 is selected from A or T; and (6) CDRL3, which contains the sequence QQYWSX1PX2T or is composed of the sequence, wherein X1 is selected from T or F, and X2 is selected from P or R; and wherein The drug is selected from one or more of the following: cytotoxic agents, cell inhibitors, chemotherapeutic agents, radiotherapy agents, anti-angiogenic agents, immunosuppressants, anti-metastatic agents, targeted anticancer agents, and other anticancer agents.

2. The antibody-drug conjugate according to claim 1, comprising: Anti-CLDN6 antibody or its antigen-binding moiety, and One or more pharmaceutical portions, said pharmaceutical portions being directly or via a linker (preferably covalently linked) to the anti-CLDN6 antibody or its antigen-binding portion, wherein The anti-CLDN6 antibody or its antigen-binding moiety includes a heavy chain variable region and a light chain variable region. The anti-CLDN6 antibody comprises: (1)CDRH1, which contains the sequence X1YNMH or is composed of the sequence, where X1 is selected from D or S; (2) CDRH2, which contains the sequence YX1X2PX3X4X5X6TX7YNQKFKG or is composed of the sequence, where X1 is selected from V or I, X2 is selected from N or Y, X3 is selected from N or G, X4 is selected from N or Q or S or A, X5 is selected from A or G or D or Q or S, X6 is selected from A or G, and X7 is selected from S or N; (3) CDRH3, which contains the sequence WX1X2YVYYYGX3DY or SEQ ID NO: 23 or is composed of it, X1 is selected from D or E or S or G, X2 is selected from A or G or S or D or Q, and X3 is selected from L or M; (4) CDRL1, which contains or consists of the sequence SEQ ID NO: 27 or SEQ ID NO: 29; (5) CDRL2, which contains or consists of the sequence SEQ ID NO: 30 or SEQ ID NO: 31; and (6) CDRL3, which contains or consists of the sequence QQYWX1TPYT or SEQ ID NO: 40, X 1 is selected from S or N; Preferably, the anti-CLDN6 antibody comprises: (1) CDRH1, which contains the sequence SEQ ID NO: 5 or consists of SEQ ID NO: 5; (2) CDRH2, which contains the sequence YX1NPNX2X3ATX4YNQKFKG or is composed of the sequence, wherein X1 is selected from V or I, X2 is selected from N or Q or S or A, X3 is selected from A or G or D or Q or S, and X4 is selected from S or N; (3) CDRH3, which contains the sequence WDGYVYYYGX1DY or is composed of the sequence, wherein X1 is selected from L or M; (4) CDRL1, which contains the sequence SEQ ID NO: 27 or consists of SEQ ID NO: 27; (5) CDRL2, which comprises the sequence SEQ ID NO: 31 or SEQ ID NO: 31; and (6) CDRL3, which contains the sequence QQYWX1TPYT or is composed of the sequence, wherein X1 is selected from S or N; More preferably, the anti-CLDN6 antibody comprises: (1) CDRH1, which contains the sequence SEQ ID NO: 5 or consists of SEQ ID NO: 5; (2) CDRH2, which contains the sequence YX1NPNNGATX2YNQKFKG or is composed of the sequence, wherein X1 is selected from V or I, and X2 is selected from S or N; (3) CDRH3, which contains the sequence WDGYVYYYGX1DY or is composed of the sequence, wherein X1 is selected from L or M; (4) CDRL1, which contains the sequence SEQ ID NO: 27 or consists of SEQ ID NO: 27; (5) CDRL2, which contains the sequence SEQ ID NO: 31 or consists of SEQ ID NO: 31; and (6) CDRL3, which contains the sequence QQYWX1TPYT or is composed of the sequence, wherein X1 is selected from S or N; Or the anti-CLDN6 antibody may contain: (1) CDRH1, which contains the sequence SYX1IX2 or is composed of the sequence, wherein X1 is selected from N or G and X2 is selected from H or S; (2) CDRH2, which contains or consists of the sequence X1IYPX2X3GX4TX5X6NEX7FKG, wherein X1 is selected from Y or E, X2 is selected from G or R, X3 is selected from N or S, X4 is selected from G or N, X5 is selected from K or Y, X6 is selected from Y or H, and X7 is selected from R or K. (3) CDRH3, which contains the sequence SEQ ID NO: 16 or SEQ ID NO: 19; (4) CDRL1, which contains the sequence SEQ ID NO: 24 or SEQ ID NO: 26, or is composed of SEQ ID NO: 24 or SEQ ID NO: 26; (5) CDRL2, which contains the sequence X1X2SNLX3S or is composed of the sequence, wherein X1 is selected from L or G, X2 is selected from A or T, and X3 is selected from E or A; and (6) CDRL3, which contains the sequence SEQ ID NO: 34 or SEQ ID NO: 179, or is composed of SEQ ID NO: 34 or SEQ ID NO: 179; Or the anti-CLDN6 antibody may contain: (1) CDRH1, which contains or consists of the sequence X1YX2MS, wherein X1 is selected from S or N and X2 is selected from G or A; (2) CDRH2, which contains the sequence TISX1GGSYTX2YPDX3X4KG or is composed of the sequence, wherein X1 is selected from S or D, X2 is selected from Y or S, X3 is selected from S or N, and X4 is selected from V or I; (3) CDRH3, which contains the sequence SEQ ID NO: 17 or SEQ ID NO: 18, or is composed of SEQ ID NO: 17 or SEQ ID NO: 18; (4) CDRL1, which contains the sequence SEQ ID NO: 25 or consists of SEQ ID NO: 25; (5) CDRL2, which contains the sequence X1X2TSLET or is composed of the sequence, wherein X1 is selected from G or A, and X2 is selected from A or T; and (6) CDRL3, which contains the sequence QQYWSXiPX2T or is composed of the sequence, wherein X1 is selected from T or F, and X2 is selected from P or R; and wherein The drug is selected from one or more of the following: cytotoxic agents, cell inhibitors, chemotherapeutic agents, radiotherapy agents, anti-angiogenic agents, immunosuppressants, anti-metastatic agents, targeted anticancer agents, and other anticancer agents.

3. An antibody-drug conjugate, comprising: Anti-CLDN6 antibody or its antigen-binding moiety, and One or more pharmaceutical portions, said pharmaceutical portions being directly or via a linker (preferably covalently linked) to the anti-CLDN6 antibody or its antigen-binding portion, wherein The anti-CLDN6 antibody or its antigen-binding moiety includes a heavy chain variable region and a light chain variable region. The heavy chain variable region includes: (i) CDRH1, which comprises any sequence shown in SEQ ID NO: 1-5 and 7 or any sequence having at least 80%, 82%, 85%, 88%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% sequence identity with SEQ ID NO: 1-5 and 7; (ii) CDRH2, comprising any sequence shown in SEQ ID NO: 8-13, 15, and 74-76 or any sequence having at least 80%, 82%, 85%, 88%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% sequence identity with SEQ ID NO: 8-13, 15, and 74-76; and (iii) CDRH3, comprising any sequence shown in SEQ ID NO: 16-21, 23 and 77-78 or any sequence having at least 80%, 82%, 85%, 88%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% sequence identity with SEQ ID NO: 16-21, 23 and 77-78; The light chain variable region includes: (i) CDRL1, which comprises any sequence shown in SEQ ID NO: 24-27 and 29 or any sequence having at least 80%, 82%, 85%, 88%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% sequence identity with SEQ ID NO: 24-27 and 29; (ii) CDRL2, comprising any sequence shown in SEQ ID NO: 30-33 or any sequence having at least 80%, 82%, 85%, 88%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% sequence identity with SEQ ID NO: 30-33; and (iii) CDRL3, comprising any sequence shown in SEQ ID NO: 34-38, 40 and 179 or any sequence having at least 80%, 82%, 85%, 88%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% sequence identity with SEQ ID NO: 34-38, 40 and 179; and wherein The drug is selected from one or more of the following: cytotoxic agents, cell inhibitors, chemotherapeutic agents, radiotherapy agents, anti-angiogenic agents, immunosuppressants, anti-metastatic agents, targeted anticancer agents, and other anticancer agents.

4. The antibody-drug conjugate according to any one of claims 1 to 3, wherein the anti-CLDN6 antibody or its antigen-binding portion comprises: (a) CDRH1 comprising or consisting of any of SEQ ID NO: 1-5 and 7; (b) CDRH2 comprising or consisting of any of SEQ ID NO: 8-13, 15, 74-76; (c) CDRH3 comprising or consisting of any of SEQ ID NO: 16-21, 23, 77-78; (d) CDRL1 comprising or consisting of any of SEQ ID NO: 24-27 and 29; (e) CDRL2 comprising or consisting of any of SEQ ID NO: 30-33; and (f) CDRL3 comprising or consisting of any of SEQ ID NO: 34-38, 40 and 179.

5. The antibody-drug conjugate according to any one of claims 1 to 3, wherein the anti-CLDN6 antibody or its antigen-binding portion comprises: (a) CDRH1 comprising or consisting of SEQ ID NO: 1; CDRH2 comprising or consisting of SEQ ID NO: 8; CDRH3 comprising or consisting of SEQ ID NO: 16; CDRL1 comprising or consisting of SEQ ID NO: 24; CDRL2 comprising or consisting of SEQ ID NO: 30; and CDRL3 comprising or consisting of SEQ ID NO: 34; (b) CDRH1 comprising or consisting of SEQ ID NO: 2; CDRH2 comprising or consisting of SEQ ID NO: 9; CDRH3 comprising or consisting of SEQ ID NO: 17; CDRL1 comprising or consisting of SEQ ID NO: 25; CDRL2 comprising or consisting of SEQ ID NO: 31; and CDRL3 comprising or consisting of SEQ ID NO: 35; (c) CDRH1 comprising or consisting of SEQ ID NO: 3; CDRH2 comprising or consisting of SEQ ID NO: 10; CDRH3 comprising or consisting of SEQ ID NO: 18; CDRL1 comprising or consisting of SEQ ID NO: 25; CDRL2 comprising or consisting of SEQ ID NO: 32; and CDRL3 comprising or consisting of SEQ ID NO: 36; (d) CDRH1 comprising or consisting of SEQ ID NO: 4; CDRH2 comprising or consisting of SEQ ID NO: 11; CDRH3 comprising or consisting of SEQ ID NO: 19; CDRL1 comprising or consisting of SEQ ID NO: 26; CDRL2 comprising or consisting of SEQ ID NO: 33; and CDRL3 comprising or consisting of SEQ ID NO: 179; (e) CDRH1 comprising or consisting of SEQ ID NO: 5; CDRH2 comprising or consisting of SEQ ID NO: 12; CDRH3 comprising or consisting of SEQ ID NO: 20; CDRL1 comprising or consisting of SEQ ID NO: 27; CDRL2 comprising or consisting of SEQ ID NO: 31; and CDRL3 comprising or consisting of SEQ ID NO: 37; (f) CDRH1 comprising or consisting of SEQ ID NO: 5; CDRH2 comprising or consisting of SEQ ID NO: 13; CDRH3 comprising or consisting of SEQ ID NO: 21; CDRL1 comprising or consisting of SEQ ID NO: 27; CDRL2 comprising or consisting of SEQ ID NO: 31; and CDRL3 comprising or consisting of SEQ ID NO: 38; or (g) CDRH1 comprising or consisting of SEQ ID NO: 7; CDRH2 comprising or consisting of SEQ ID NO: 15; CDRH3 comprising or consisting of SEQ ID NO: 23; CDRL1 comprising or consisting of SEQ ID NO: 29; CDRL2 comprising or consisting of SEQ ID NO: 30; and CDRL3 comprising or consisting of SEQ ID NO: 40; or (h) comprising CDRH1 shown or composed of SEQ ID NO: 5; CDRH2 shown or composed of SEQ ID NO: 12; CDRH3 shown or composed of SEQ ID NO: 20; CDRL1 shown or composed of SEQ ID NO: 27; CDRL2 shown or composed of SEQ ID NO: 31; and CDRL3 shown or composed of SEQ ID NO: 38; or (i) CDRH1 comprising or consisting of SEQ ID NO: 7; CDRH2 comprising or consisting of SEQ ID NO: 74; CDRH3 comprising or consisting of SEQ ID NO: 23; CDRL1 comprising or consisting of SEQ ID NO: 29; CDRL2 comprising or consisting of SEQ ID NO: 30; and CDRL3 comprising or consisting of SEQ ID NO: 40; or (j) CDRH1 comprising or consisting of SEQ ID NO: 5; CDRH2 comprising or consisting of SEQ ID NO: 75; CDRH3 comprising or consisting of SEQ ID NO: 20; CDRL1 comprising or consisting of SEQ ID NO: 27; CDRL2 comprising or consisting of SEQ ID NO: 31; and CDRL3 comprising or consisting of SEQ ID NO: 37; or (k) comprising CDRH1 as shown or composed of SEQ ID NO: 5; CDRH2 as shown or composed of SEQ ID NO: 76; CDRH3 as shown or composed of SEQ ID NO: 20; CDRL1 as shown or composed of SEQ ID NO: 27; CDRL2 as shown or composed of SEQ ID NO: 31; and CDRL3 as shown or composed of SEQ ID NO: 37; or (1) CDRH1 comprising or consisting of SEQ ID NO: 5; CDRH2 comprising or consisting of SEQ ID NO: 12; CDRH3 comprising or consisting of SEQ ID NO: 77; CDRL1 comprising or consisting of SEQ ID NO: 27; CDRL2 comprising or consisting of SEQ ID NO: 31; and CDRL3 comprising or consisting of SEQ ID NO: 37; or (m) includes CDRH1 shown or composed of SEQ ID NO: 5; CDRH2 shown or composed of SEQ ID NO: 12; CDRH3 shown or composed of SEQ ID NO: 78; CDRL1 shown or composed of SEQ ID NO: 27; CDRL2 shown or composed of SEQ ID NO: 31; and CDRL3 shown or composed of SEQ ID NO:

37.

6. The antibody-drug conjugate according to any one of claims 1 to 5, wherein the heavy chain variable region comprises any amino acid sequence of SEQ ID NO: 41-46, 48-60, 79-83 or a sequence thereof, or any amino acid sequence of SEQ ID NO: 41-46, 48-60, 79-83 having at least 80%, for example at least 82%, 85%, 88%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% sequence identity with the sequence of SEQ ID NO: 41-46, 48-60, 79-83; the light chain variable region comprises any amino acid sequence of SEQ ID NO: 61-66, 68-73 or a sequence thereof, or a sequence thereof having at least 80%, for example at least 82%, 85%, 88%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% sequence identity with the sequence of SEQ ID NO: 41-46, 48-60, 79-83; The sequences NO: 61-66, 68-73 have at least 80%, for example at least 82%, 85%, 88%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% sequence identity of any amino acid sequence or a sequence composed thereof.

7. The antibody-drug conjugate according to any one of claims 1 to 6, wherein the anti-CLDN6 antibody or its antigen-binding portion comprises: (a) A heavy chain variable region comprising or consisting of the amino acid sequence of SEQ ID NO: 41 and a light chain variable region comprising or consisting of the amino acid sequence of SEQ ID NO: 61; or (b) a heavy chain variable region comprising or consisting of the amino acid sequence of SEQ ID NO: 42 and a light chain variable region comprising or consisting of the amino acid sequence of SEQ ID NO: 62; or (c) A heavy chain variable region comprising or consisting of the amino acid sequence of SEQ ID NO: 43 and a light chain variable region comprising or consisting of the amino acid sequence of SEQ ID NO: 63; or (d) A heavy chain variable region comprising or consisting of the amino acid sequence of SEQ ID NO: 44 and a light chain variable region comprising or consisting of the amino acid sequence of SEQ ID NO: 64; or (e) a heavy chain variable region comprising or consisting of any of the amino acid sequences in SEQ ID NO: 45 or 80-83, and a light chain variable region comprising or consisting of the amino acid sequence in SEQ ID NO: 65; or (f) A heavy chain variable region comprising or consisting of the amino acid sequence of SEQ ID NO: 46 or 45 and a light chain variable region comprising or consisting of the amino acid sequence of SEQ ID NO: 66; or (g) A heavy chain variable region comprising or consisting of the amino acid sequence of SEQ ID NO: 48 or 79 and a light chain variable region comprising or consisting of the amino acid sequence of SEQ ID NO: 68; or (h) a heavy chain variable region comprising or consisting of any of the amino acid sequences in SEQ ID NO: 49-52 and a light chain variable region comprising or consisting of the amino acid sequence in SEQ ID NO: 69; or (i) a heavy chain variable region comprising or consisting of any of the amino acid sequences in SEQ ID NO: 49-52 and a light chain variable region comprising or consisting of the amino acid sequence in SEQ ID NO: 70; or (j) A heavy chain variable region comprising or consisting of the amino acid sequence of SEQ ID NO: 53 or 54 and a light chain variable region comprising or consisting of the amino acid sequence of SEQ ID NO: 71; or (k) a heavy chain variable region comprising or consisting of any of the amino acid sequences in SEQ ID NO: 53-56 and a light chain variable region comprising or consisting of the amino acid sequence in SEQ ID NO: 72; or (1) A heavy chain variable region comprising or consisting of any of the amino acid sequences in SEQ ID NO: 57-60 and a light chain variable region comprising or consisting of the amino acid sequence in SEQ ID NO:

73.

8. An antibody-drug conjugate, comprising: Anti-CLDN6 antibody or its antigen-binding moiety, and One or more pharmaceutical portions, said pharmaceutical portions being directly or via a linker (preferably covalently linked) to the anti-CLDN6 antibody or its antigen-binding portion, wherein The anti-CLDN6 antibody or its antigen-binding portion comprises: (a) A heavy chain variable region comprising an amino acid sequence or being composed thereof that is at least 80% identical to the sequence of SEQ ID NO: 41, and a light chain variable region comprising an amino acid sequence or being composed thereof that is at least 80% identical to the sequence of SEQ ID NO: 61; or (b) a heavy chain variable region comprising or consisting of an amino acid sequence identical to at least 80% of the sequence of SEQ ID NO: 42 and a light chain variable region comprising or consisting of an amino acid sequence identical to at least 80% of the sequence of SEQ ID NO: 62; or (c) A heavy chain variable region comprising or consisting of an amino acid sequence identical to at least 80% of the sequence of SEQ ID NO: 43 and a light chain variable region comprising or consisting of an amino acid sequence identical to at least 80% of the sequence of SEQ ID NO: 63; or (d) A heavy chain variable region comprising or consisting of an amino acid sequence identical to at least 80% of the sequence of SEQ ID NO: 44, and a light chain variable region comprising or consisting of an amino acid sequence identical to at least 80% of the sequence of SEQ ID NO: 64; or (e) a heavy chain variable region comprising an amino acid sequence or being composed of an amino acid sequence identical to at least 80% of any of the sequences in SEQ ID NO: 45 or 80-83, and a light chain variable region comprising an amino acid sequence or being composed of an amino acid sequence identical to at least 80% of the sequence in SEQ ID NO: 65; or (f) a heavy chain variable region comprising or consisting of an amino acid sequence identical to at least 80% of the sequence of SEQ ID NO: 46 or 45, and a light chain variable region comprising or consisting of an amino acid sequence identical to at least 80% of the sequence of SEQ ID NO: 66; or (g) a heavy chain variable region comprising or consisting of an amino acid sequence identical to at least 80% of the sequence of SEQ ID NO: 48 or 79, and a light chain variable region comprising or consisting of an amino acid sequence identical to at least 80% of the sequence of SEQ ID NO: 68; or (h) a heavy chain variable region comprising an amino acid sequence or being composed of an amino acid sequence that is at least 80% identical to any of the sequences in SEQ ID NO: 49-52, and a light chain variable region comprising an amino acid sequence or being composed of an amino acid sequence that is at least 80% identical to any of the sequences in SEQ ID NO: 69; or (i) a heavy chain variable region comprising or consisting of an amino acid sequence that is at least 80% sequence identical to any of the sequences in SEQ ID NO: 49-52, and a light chain variable region comprising or consisting of an amino acid sequence that is at least 80% sequence identical to any of the sequences in SEQ ID NO: 70; or (j) a heavy chain variable region comprising an amino acid sequence identical to or consisting of at least 80% of the sequence of SEQ ID NO: 53 or 54, and a light chain variable region comprising an amino acid sequence identical to or consisting of at least 80% of the sequence of SEQ ID NO: 71; or (k) a heavy chain variable region comprising an amino acid sequence or being composed of any of the sequences in SEQ ID NO: 53-56 that is at least 80% sequence identical, and a light chain variable region comprising an amino acid sequence or being composed of an amino acid sequence that is at least 80% sequence identical, to any of the sequences in SEQ ID NO: 72; or (1) A heavy chain variable region comprising an amino acid sequence or being composed of any of the sequences in SEQ ID NO: 57-60 with at least 80% sequence identity and a light chain variable region comprising an amino acid sequence or being composed of at least 80% sequence identity of SEQ ID NO:

73.

9. An antibody-drug conjugate, comprising: Anti-CLDN6 antibody or its antigen-binding moiety, and One or more pharmaceutical portions, said pharmaceutical portions being directly or via a linker (preferably covalently linked) to the anti-CLDN6 antibody or its antigen-binding portion, wherein The anti-CLDN6 antibody or its antigen-binding portion comprises a complementarity-determining region sequence selected from the sequences shown in SEQ ID NO: 41-46, 48-60, 79-83 and a complementarity-determining region sequence selected from the sequences shown in SEQ ID NO: 61-66, 68-73; and wherein The drug is selected from one or more of the following: cytotoxic agents, cell inhibitors, chemotherapeutic agents, radiotherapy agents, anti-angiogenic agents, immunosuppressants, anti-metastatic agents, targeted anticancer agents, and other anticancer agents.

10. An antibody-drug conjugate, comprising: Anti-CLDN6 antibody or its antigen-binding moiety, and One or more pharmaceutical portions, said pharmaceutical portions being directly or via a linker (preferably covalently linked) to the anti-CLDN6 antibody or its antigen-binding portion, wherein The anti-CLDN6 antibody or its antigen-binding moiety includes a heavy chain variable region and a light chain variable region. The anti-CLDN6 antibody comprises: (1) CDRH1, which contains or consists of SEQ ID NO: 5; (2) CDRH2, which contains or consists of SEQ ID NO: 12, or which contains or consists of the sequence YX1NPNNGAX2X3YNQKFKG, X 1 is selected from A, I, L or V, X2 is selected from S or T, X3 is selected from S or N; preferably, CDRH2, which contains or consists of the sequence SEQ ID NO: 12, 91, 92, 93, 94, 119, 120, 121, 122, 123, 124 or 125; (3) CDRH3, which contains or consists of SEQ ID NO: 20, or It contains or is composed of the sequence WDGYX1YYYGX2DX3, wherein X1 is selected from V or S, X2 is selected from V, L or M, and X3 is selected from Y or F; preferably, CDRH3, which contains or is composed of the sequence SEQ ID NO: 20, 95, 96, 97, 126, 127, 128, 129, 130, or 131; (4) CDRL1, which contains or consists of SEQ ID NO: 27, or contains the sequence KASX1HX2NX3WLA or consists of the sequence, wherein X1 is selected from E or D, X2 is selected from I or V, and X3 is selected from H or Q; preferably, CDRL1 contains or consists of SEQ ID NO: 27, 98, 99, 100, 132, 133, 134, or 135; (5) CDRL2, which contains or consists of SEQ ID NO: 31, or which contains or consists of SEQ ID NO: 101; and (6) CDRL3, which contains or is composed of SEQ ID NO: 37, or which contains or is composed of QQYX1X2TPYX3, wherein X1 is selected from W or G, X2 is selected from s, H or N, and X3 is selected from s or T; preferably, CDRL3 contains or is composed of sEQ ID NO: 37, 102, 103, 104, 136, 137, 138, 139, 140, 141 or 142; Preferably, the anti-CLDN6 antibody comprises: (1) CDRH1, which contains or consists of SEQ ID NO: 5; (2) CDRH2, which contains or consists of SEQ ID NO: 12, or contains or consists of the sequence YX1NPNNGAX2X3YNQKFKG, where X1 is selected from A, I, L or V, X2 is selected from S or T, and X3 is selected from S or N; preferably, CDRH2 contains or consists of the sequence SEQ ID NO: 12, 91, 92, 93, 94, 119, 120, 121, 122, 123, 124 or 125; (3) CDRH3, which contains or consists of SEQ ID NO: 20; (4) CDRL1, which contains or consists of SEQ ID NO: 27; (5) CDRL2, which contains or consists of SEQ ID NO: 31; and (6) CDRL3, which contains or consists of SEQ ID NO: 37; Alternatively, the anti-CLDN6 antibody may comprise: (1) CDRH1, which contains or consists of SEQ ID NO: 5; (2) CDRH2, which contains or consists of SEQ ID NO: 12; (3) CDRH3, which contains or consists of SEQ ID NO: 20, or contains the sequence WDGYX1YYYGX2DX3 or consists of the sequence, wherein X1 is selected from V or S, X2 is selected from V, L or M, and X3 is selected from Y or F; preferably, CDRH3 contains or consists of the sequence SEQ ID NO: 20, 95, 96, 97, 126, 127, 128, 129, 130, or 131; (4) CDRL1, which contains or consists of SEQ ID NO: 27; (5) CDRL2, which contains or consists of SEQ ID NO: 31; and (6) CDRL3, which contains or consists of SEQ ID NO: 37; Alternatively, the anti-CLDN6 antibody may comprise: (1) CDRH1, which contains or consists of SEQ ID NO: 5; (2) CDRH2, which contains or consists of SEQ ID NO: 12; (3) CDRH3, which contains or consists of SEQ ID NO: 20; (4) CDRL1, which contains or consists of SEQ ID NO: 27, or contains the sequence KASX1HX2NX3WLA or consists of the sequence, wherein X1 is selected from E or D, X2 is selected from I or V, and X3 is selected from H or Q; preferably, CDRL1 contains or consists of SEQ ID NO: 27, 98, 99, 100, 132, 133, 134, or 135; (5) CDRL2, which contains or consists of SEQ ID NO: 31; and (6) CDRL3, which contains or consists of sEQ ID NO: 37; Alternatively, the anti-CLDN6 antibody may comprise: (1) CDRH1, which contains or consists of SEQ ID NO: 5; (2) CDRH2, which contains or consists of SEQ ID NO: 12; (3) CDRH3, which contains or consists of SEQ ID NO: 20; (4) CDRL1, which contains or consists of SEQ ID NO: 27; (5) CDRL2, which contains or consists of SEQ ID NO: 31, or which contains or consists of SEQ ID NO: 101; and (6) CDRL3, which contains or consists of SEQ ID NO: 37; Alternatively, the anti-CLDN6 antibody may comprise: (1) CDRH1, which contains or consists of SEQ ID NO: 5; (2) CDRH2, which contains or consists of SEQ ID NO: 12; (3) CDRH3, which contains or consists of SEQ ID NO: 20; (4) CDRL1, which contains or consists of SEQ ID NO: 27; (5) CDRL2, which contains or consists of SEQ ID NO: 31; and (6) CDRL3, which comprises or is composed of SEQ ID NO: 37, or comprises or is composed of QQYX1X2TPYX3, wherein X1 is selected from W or G, X2 is selected from S, H or N, and X3 is selected from S or T; preferably, CDRL3 comprises or is composed of SEQ ID NO: 37, 102, 103, 104, 136, 137, 138, 139, 140, 141 or 142; Alternatively, the anti-CLDN6 antibody may comprise: (1) CDRH1, which contains or consists of SEQ ID NO: 5; (2) CDRH2, which includes or consists of any one of SEQ ID NO: 12, 91-94, 119-125; (3) CDRH3, which includes or consists of any one of SEQ ID NO: 20, 95-97, 126-131; (4) CDRL1, which includes or consists of any one of SEQ ID NO: 27, 98-99, 132-135; (5) CDRL2, which contains or consists of SEQ ID NO: 31 or 101; (6) CDRL3, which includes or consists of any one of SEQ ID NO: 37, 102-104, 136-142; Preferably, the anti-CLDN6 antibody comprises or is composed of CDRs as shown in Table L, and wherein The drug is selected from one or more of the following: cytotoxic agents, cell inhibitors, chemotherapeutic agents, radiotherapy agents, anti-angiogenic agents, immunosuppressants, anti-metastatic agents, targeted anticancer agents, and other anticancer agents.

11. An antibody-drug conjugate, comprising: Anti-CLDN6 antibody or its antigen-binding moiety, and One or more pharmaceutical portions, said pharmaceutical portions being directly or via a linker (preferably covalently linked) to the anti-CLDN6 antibody or its antigen-binding portion, wherein The anti-CLDN6 antibody or its antigen-binding moiety includes a heavy chain variable region and a light chain variable region. The heavy chain variable region comprises any amino acid sequence of SEQ ID NO: 105-111 or a sequence thereof, or any amino acid sequence of SEQ ID NO: 105-111 having at least 80%, for example, at least 82%, 85%, 88%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% sequence identity with the sequence of SEQ ID NO: 105-111; the light chain variable region comprises any amino acid sequence of SEQ ID NO: 69 or a sequence thereof, or any amino acid sequence of SEQ ID NO: 69 having at least 80%, for example, at least 82%, 85%, 88%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% sequence identity with the sequence of SEQ ID NO: 69; or The heavy chain variable region comprises a sequence of SEQ ID NO: 52 or thereof, or any amino acid sequence or a sequence comprising thereof having at least 80%, for example, at least 82%, 85%, 88%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% sequence identity with the sequence of SEQ ID NO: 52; the light chain variable region comprises any amino acid sequence of SEQ ID NO: 112-118 or a sequence comprising thereof, or any amino acid sequence or a sequence comprising thereof having at least 80%, for example, at least 82%, 85%, 88%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% sequence identity with the sequence of SEQ ID NO: 112-118, and wherein... The drug is selected from one or more of the following: cytotoxic agents, cell inhibitors, chemotherapeutic agents, radiotherapy agents, anti-angiogenic agents, immunosuppressants, anti-metastatic agents, targeted anticancer agents, and other anticancer agents.

12. The antibody-drug conjugate according to any one of claims 1 to 11, wherein the anti-CLDN6 antibody is a monoclonal antibody.

13. The antibody-drug conjugate according to any one of claims 1 to 12, wherein the anti-CLDN6 antibody is a chimeric antibody or a humanized antibody.

14. The antibody-drug conjugate according to any one of claims 1 to 13, wherein the anti-CLDN6 antibody comprises a constant region of IgG, preferably selected from the constant regions of IgG1, IgG2, IgG3, or IgG4, more preferably selected from the constant region of IgG1.

15. The antibody-drug conjugate according to any one of claims 1 to 14, wherein the anti-CLDN6 antibody or its antigen-binding portion comprises or is composed of a heavy chain consisting of any sequence selected from the group consisting of: a polypeptide having at least 80%, 82%, 85%, 88%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% sequence identity with SEQ ID NO: 143-167, SEQ ID NO: 87, or SEQ ID NO: 89; and a light chain comprising or is composed of any sequence selected from the group consisting of: a polypeptide having at least 80%, 82%, 85%, 88%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% sequence identity with SEQ ID NO: 168-178, SEQ ID NO: 88, or SEQ ID NO:

100.

16. The antibody-drug conjugate according to any one of claims 1 to 15, wherein the drug portion is selected from microtubule inhibitors, DNA double-strand disruptors, topoisomerase inhibitors, DNA alkylating agents, RNA polymerase inhibitors, RNA cleavage enzyme inhibitors, Bcl-xL inhibitors, antimitotic agents, sodium-potassium ion pump ATPase inhibitors, matrix metalloproteinase inhibitors, and immune agonists. Preferably, the drug portion is selected from olistatin derivatives, maytansine derivatives, pyrrolobenzodiazepine dimer derivatives, camptothecin derivatives, or cazithromycin derivatives.

17. The antibody-drug conjugate according to any one of claims 1 to 16, wherein the drug portion is selected from salipodin, monomethylolpropionate E (MMAE), monomethylolpropionate F (MMAF), PF-06380101, DXd, topotecan, irinotecan, 9-aminocamptothecin, 7-ethyl-10-hydroxycamptothecin (SN38), maytansin DM1, maytansin DM4, PDB dimer, or N-acetyl-γ11 kazimidycin.

18. The antibody-drug conjugate according to any one of claims 1 to 17, wherein the linker is a cleavable linker, preferably comprising an enzyme-cleavable peptide chain portion.

19. The antibody-drug conjugate according to any one of claims 1 to 18, wherein the linker comprises a structure selected from valine-citrulline (VC), valine-alanine (VA), phenylalanine-lysine (FK), and glycine-glycine-phenylalanine-glycine (GGFG), CL2A, or CL2E.

20. The antibody-drug conjugate according to any one of claims 1 to 19, wherein the linker is selected from maleimide-hexanoyl-valine-citrulline-p-aminobenzyloxycarbonyl (MC-VC-PAB), maleimide-hexanoyl-valine-alanine (MC-VA), maleimide-butyric acid-valine-citrulline (MB-VC), maleimide-hexanoyl-glycine-glycine-phenylalanine-glycine (MC-GGFG) or valine-citrulline-p-aminobenzyloxycarbonyl (VC-PAB).

21. The antibody-drug conjugate according to any one of claims 1 to 20, wherein the anti-CLDN6 antibody is selected from PiH1001, PiH1002, PiH1003, PiH1004, PiH1005, PiH1006, PiH1007, PiH1008, PiH2001, PiH2004, PiH2005, PiH2006, PiH2007, PiH2008, PiH2009, PiH2010, PiH2011, PiH2012, and PiH2012-1; and the anti-CLDN6 antibody is conjugated with VC-PAB-MMAE, GGFG-MMAE, VC-PAB-MMAF, GGFG-MMAF, VC-PAB-DXd, GGFG-DXd, VC-PAB-DM1, GGFG-DM1, or CL2A-SN38.

22. The antibody-drug conjugate according to any one of claims 1 to 20, wherein the anti-CLDN6 antibody is selected from PiH1001-M1, PiH1001-M2, PiH1001-M3, PiH1001-M4, PiH1002-M1, PiH1002-M2, PiH1002-M3, PiH1002-M4, PiH1003-M1, PiH1003-M2, PiH1003-M3, PiH1003-M4, PiH1004-M1, PiH1004-M2, PiH1004-M3, PiH1004-M4, PiH1005-M1, PiH1005-M2, PiH1005-M3, ... PiH1005-M4, PiH1006-M1, PiH1006-M2, PiH1006-M3, PiH1006-M4, PiH1007-M1, PiH1007-M2, PiH1007-M3, PiH1007-M4, PiH1008-M1, PiH1008-M2, PiH1008-M3, PiH1008-M4; and the anti-CLDN6 antibody is conjugated with VC-PAB-MMAE, GGFG-MMAE, VC-PAB-MMAF, GGFG-MMAF, VC-PAB-DXd, GGFG-DXd, VC-PAB-DM1, GGFG-DM1 or CL2A-SN38.

23. The antibody-drug conjugate according to any one of claims 1 to 20, wherein the anti-CLDN6 antibody is selected from PiH1001, PiH1002, PiH1003, PiH1004, PiH1005, PiH1006, PiH1007, PiH1008 and PiH2001, PiH2004, PiH2005, PiH2006, PiH2007, PiH2008, PiH2009, PiH2010, PiH2011, PiH2012, PiH2012-1; and the anti-CLDN6 antibody is conjugated to MC-VC-PAB-MMAE, MC-GGFG-MMAE, MC-VC-PAB-MMAF, MC-GGFG-MMAF, MC-VC-PAB-DXd, MC-GGFG-DXd, MC-VC-PAB-DM1 or MC-GGFG-DM1.

24. The antibody-drug conjugate according to any one of claims 1 to 20, wherein the anti-CLDN6 antibody is selected from PiH1001-M1, PiH1001-M2, PiH1001-M3, PiH1001-M4, PiH1002-M1, PiH1002-M2, PiH1002-M3, PiH1002-M4, PiH1003-M1, PiH1003-M2, PiH1003-M3, PiH1003-M4, PiH1004-M1, PiH1004-M2, PiH1004-M3, PiH1004-M4, PiH1005-M1, PiH1005-M2, PiH1005-M3, PiH1005 -M4, PiH1006-M1, PiH1006-M2, PiH1006-M3, PiH1006-M4, PiH1007-M1, PiH1007-M2, PiH1007-M3, PiH1007-M4, PiH1008-M1, PiH1008-M2, PiH1008-M3, PiH1008-M4; and the anti-CLDN6 antibody is conjugated with MC-VC-PAB-MMAE, MC-GGFG-MMAE, MC-VC-PAB-MMAF, MC-GGFG-MMAF, MC-VC-PAB-DXd, MC-GGFG-DXd, MC-VC-PAB-DM1 or MC-GGFG-DM1.

25. A pharmaceutical composition or kit comprising the antibody-drug conjugate of any one of claims 1-24, and a pharmaceutically acceptable carrier, diluent, and / or excipient.

26. Use of the antibody-drug conjugate of any one of claims 1-24 or the pharmaceutical composition or kit of claim 25 in the preparation of a medicament for treating diseases associated with CLDN6 expression.

27. The use according to claim 26, wherein the disease associated with CLDN6 expression is cancer, preferably selected from one or more of ovarian cancer, lung cancer, gastric cancer, breast cancer, liver cancer, pancreatic cancer, skin cancer, malignant melanoma, head and neck cancer, sarcoma, bile duct cancer, bladder cancer, kidney cancer, colon cancer, placental choriocarcinoma, teratoma, cervical cancer, testicular cancer, uterine carcinosarcoma, endometrial cancer, and brain cancer.

28. The use according to claim 26 or 27, wherein the disease associated with CLDN6 expression is selected from one or more of ovarian cancer, testicular cancer, uterine carcinosarcoma, endometrial cancer, ovarian teratoma, gastric cancer, liver cancer, lung cancer, and bile duct cancer.

29. The use according to claim 26, wherein the disease associated with CLDN6 expression is a fibrotic disease, preferably selected from one or more of fibrosis of the lungs, liver, colon, gallbladder, and stomach, and more preferably selected from one or more of hepatitis, pulmonary fibrosis, liver fibrosis, cirrhosis, scleroderma, and biliary atresia.

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