Anti-crr8 monoclonal antibodies and uses thereof

Abstract

The present application relates to an anti-CCR8 monoclonal antibody and application thereof, in particular, the present application relates to an anti-CCR8 monoclonal antibody which can be combined with CCR8 derived from primates. Further relates to a pharmaceutical composition comprising the anti-CCR8 monoclonal antibody, and application of the anti-CCR8 monoclonal antibody and / or the pharmaceutical composition in preventing and / or treating tumors or cancers.

Description

Technical Field

[0001] This invention relates to the field of pharmaceutical technology, and more specifically, to anti-CCR8 monoclonal antibodies and their applications. Background Technology

[0002] Chemokine (CC motif) receptor 8 (CCR8) is a member of the β-chemokine receptor family and is a seven-transmembrane G protein-coupled receptor. In humans and mice, CCR8 is primarily expressed on regulatory T cells (Tregs) and a small portion on Th2 cells, but not on Th1 cells. Analysis of Treg CCR8... + Upregulation is associated with the occurrence, progression, and survival of various tumors.

[0003] CCL1 is one of the major ligands of CCR8. CCL1 overexpression occurs in various tumor tissue microenvironments and recruits CCR8. + Treg cells infiltrate tumor tissue, creating an immunosuppressive microenvironment. By blocking CCL1-CCR8 activity, CCR8 in the tumor environment can be eliminated. + Treg, or blocking CCL1-mediated CCR8 + Tregs migrate to tumor tissues, which can block the immunosuppressive effect caused by Tregs, thereby increasing the anti-tumor effect. This is a new approach to tumor immunotherapy. Summary of the Invention

[0004] This invention provides an anti-CCR8 antibody that has high affinity and specificity for human CCR8 protein, effectively blocking the binding of CCL1 to CCR8 and inhibiting downstream signal transduction; in addition, it can also clear CCR8 positive cells by mediating antibody-dependent cytotoxicity and complement-dependent cytotoxicity.

[0005] Specifically, on one hand, the present invention provides a fully human antibody or antigen-binding fragment that specifically binds to human CCR8, wherein the antibody comprises a heavy chain variable region and a light chain variable region, the heavy chain variable region comprising complementarity-determining regions: H-CDR1, H-CDR2, and H-CDR3, and the light chain variable region comprising complementarity-determining regions: L-CDR1, L-CDR2, and L-CDR3, wherein,

[0006] The H-CDR1 has the amino acid sequence shown in SEQ ID NO: 1, SEQ ID NO: 7, SEQ ID NO: 13, SEQ ID NO: 19, SEQ ID NO: 25 or SEQ ID NO: 31;

[0007] The H-CDR2 has the amino acid sequence shown in SEQ ID NO: 2, SEQ ID NO: 8, SEQ ID NO: 14, SEQ ID NO: 20, SEQ ID NO: 26 or SEQ ID NO: 32;

[0008] The H-CDR3 has the amino acid sequence shown in SEQ ID NO: 3, SEQ ID NO: 9, SEQ ID NO: 15, SEQ ID NO: 21, SEQ ID NO: 27 or SEQ ID NO: 33;

[0009] The L-CDR1 has the amino acid sequence shown in SEQ ID NO: 4, SEQ ID NO: 10, SEQ ID NO: 16, SEQ ID NO: 22, SEQ ID NO: 28 or SEQ ID NO: 34;

[0010] The L-CDR2 has the amino acid sequence shown in SEQ ID NO: 5, SEQ ID NO: 11, SEQ ID NO: 17, SEQ ID NO: 23, SEQ ID NO: 29 or SEQ ID NO: 35;

[0011] The L-CDR3 has the amino acid sequence shown in SEQ ID NO: 6, SEQ ID NO: 12, SEQ ID NO: 18, SEQ ID NO: 24, SEQ ID NO: 30 or SEQ ID NO: 36.

[0012] The H-CDR1 has the amino acid sequence shown in SEQ ID NO: 1, SEQ ID NO: 7, SEQ ID NO: 13, SEQ ID NO: 19, SEQ ID NO: 25 or SEQ ID NO: 31.

[0013] SSSAAWS (SEQ ID NO: 1).

[0014] TYWIG (SEQ ID NO: 7).

[0015] SKSVGWH (SEQ ID NO: 13).

[0016] SNSVGWH (SEQ ID NO: 19).

[0017] SKSVGWH (SEQ ID NO: 25).

[0018] SYAIS (SEQ ID NO: 31).

[0019] The H-CDR2 has the amino acid sequence shown in SEQ ID NO: 2, SEQ ID NO: 8, SEQ ID NO: 14, SEQ ID NO: 20, SEQ ID NO: 26 or SEQ ID NO: 32.

[0020] RTYYRSKWRSDYAVSVKS (SEQ ID NO: 2).

[0021] IINPDDSQARYSPSFQG (SEQ ID NO: 8).

[0022] RTYYRSRWNDDYAVSVKS (SEQ ID NO: 14).

[0023] RTYYRSRWNNDYAVSVKS (SEQ ID NO: 20).

[0024] RTYYRSKWNNDYAISVKS (SEQ ID NO: 26).

[0025] IINPSGGNTRYAQKFQG (SEQ ID NO: 32).

[0026] The H-CDR3 has the amino acid sequence shown in SEQ ID NO: 3, SEQ ID NO: 9, SEQ ID NO: 15, SEQ ID NO: 21, SEQ ID NO: 27 or SEQ ID NO: 33.

[0027] GRWSGFDI (SEQ ID NO: 3).

[0028] PGGP (SEQ ID NO: 9).

[0029] GFRYSFDY (SEQ ID NO: 15).

[0030] GFRYSFDY (SEQ ID NO: 21).

[0031] GYNFGFDY (SEQ ID NO: 27).

[0032] DGFGMDSSGYYRLRY (SEQ ID NO: 33).

[0033] The L-CDR1 has the amino acid sequence shown in SEQ ID NO: 4, SEQ ID NO: 10, SEQ ID NO: 16, SEQ ID NO: 22, SEQ ID NO: 28 or SEQ ID NO: 34.

[0034] RSSQSLLHSNGYNYLA (SEQ ID NO: 4).

[0035] RSSHSPQFSDGNNYVS (SEQ ID NO: 10).

[0036] SGSKSNIGNRTVN (SEQ ID NO: 16).

[0037] SGSSSNIGSRNVN (SEQ ID NO: 22).

[0038] SGSSSNIGKNPVS (SEQ ID NO: 28).

[0039] RSSQSLVHSDGNTYLS (SEQ ID NO: 34).

[0040] The L-CDR2 has the amino acid sequence shown in SEQ ID NO: 5, SEQ ID NO: 11, SEQ ID NO: 17, SEQ ID NO: 23, SEQ ID NO: 29 or SEQ ID NO: 35.

[0041] LGSNRAS (SEQ ID NO: 5).

[0042] RASNRAS (SEQ ID NO: 11).

[0043] GTDQRPS (SEQ ID NO: 17).

[0044] SSNQRPS (SEQ ID NO: 23).

[0045] DNNKRPS (SEQ ID NO: 29).

[0046] KISNRFS (SEQ ID NO: 35).

[0047] The L-CDR3 has the amino acid sequence shown in SEQ ID NO: 6, SEQ ID NO: 12, SEQ ID NO: 18, SEQ ID NO: 24, SEQ ID NO: 30 or SEQ ID NO: 36.

[0048] MQSLQTPPT (SEQ ID NO: 6).

[0049] MQGTHWPWT (SEQ ID NO: 12).

[0050] SSWDDSLKVLL (SEQ ID NO: 18).

[0051] ATWDDSLKVLL (SEQ ID NO: 24).

[0052] ATWDTKGTRLSSVGV (SEQ ID NO: 30).

[0053] MQGTRFPHT (SEQ ID NO: 36).

[0054] In some implementations, the heavy chain variable region comprises complementary determining regions: H-CDR1, H-CDR2, and H-CDR3, and the light chain variable region comprises complementary determining regions: L-CDR1, L-CDR2, and L-CDR3, selected from a combination of the following groups:

[0055] (1) The H-CDR1, H-CDR2, and H-CDR3 respectively have the amino acid sequences shown in SEQ ID NO: 1, SEQ ID NO: 2, and SEQ ID NO: 3; and the L-CDR1, L-CDR2, and L-CDR3 respectively have the amino acid sequences shown in SEQ ID NO: 4, SEQ ID NO: 5, and SEQ ID NO: 6; or

[0056] (2) The H-CDR1, H-CDR2, and H-CDR3 have the amino acid sequences shown in SEQ ID NO: 7, SEQ ID NO: 8, and SEQ ID NO: 9, respectively; and the L-CDR1, L-CDR2, and L-CDR3 have the amino acid sequences shown in SEQ ID NO: 10, SEQ ID NO: 11, and SEQ ID NO: 12, respectively; or

[0057] (3) The H-CDR1, H-CDR2, and H-CDR3 respectively have the amino acid sequences shown in SEQ ID NO: 13, SEQ ID NO: 14, and SEQ ID NO: 15; and the L-CDR1, L-CDR2, and L-CDR3 respectively have the amino acid sequences shown in SEQ ID NO: 16, SEQ ID NO: 17, and SEQ ID NO: 18; or

[0058] (4) The H-CDR1, H-CDR2, and H-CDR3 respectively have the amino acid sequences shown in SEQ ID NO: 19, SEQ ID NO: 20, and SEQ ID NO: 21; and the L-CDR1, L-CDR2, and L-CDR3 respectively have the amino acid sequences shown in SEQ ID NO: 22, SEQ ID NO: 23, and SEQ ID NO: 24; or

[0059] (5) The H-CDR1, H-CDR2, and H-CDR3 respectively have the amino acid sequences shown in SEQ ID NO: 25, SEQ ID NO: 26, and SEQ ID NO: 27; and the L-CDR1, L-CDR2, and L-CDR3 respectively have the amino acid sequences shown in SEQ ID NO: 28, SEQ ID NO: 29, and SEQ ID NO: 30; or

[0060] (6) The H-CDR1, H-CDR2 and H-CDR3 have the amino acid sequences shown in SEQ ID NO: 31, SEQ ID NO: 32 and SEQ ID NO: 33, respectively; and the L-CDR1, L-CDR2 and L-CDR3 have the amino acid sequences shown in SEQ ID NO: 34, SEQ ID NO: 35 and SEQ ID NO: 36, respectively.

[0061] In some embodiments, the fully human antibody comprises at least one of a heavy chain variable region framework region and a light chain variable region framework region, and at least a portion of at least one of the heavy chain variable region framework region and the light chain variable region framework region is derived from at least one of the human antibody or a mutant thereof.

[0062] In some embodiments, the heavy chain variable region of the fully human antibody contains an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99% identity with any one of SEQ ID NO: 59-64.

[0063] QVQLQQSGPGLVRPSQTLSLTCAISGDSISSSSAAWSWIRQSPSGGLEWLGRTYYRSKWRSDYAVSVKSRISVTPDTSKNQFSLQLNSVTPEDTAKYFCARGRWSGFDIWGQGTMVTVSS (SEQ ID NO: 59).

[0064] QVQLVQSGAEVKKPGESLKISCKGSGYRFTTYWIGWVRQMPGKGLEWMGIINPDDSQARYSPSFQGQVTISADKSISTAYVQWSSLKASDSAIYYCARGGPWGQGTLVTVSS (SEQ ID NO: 60).

[0065] QVQLQQSGPGLVKPSQTLSLTCAISGDSVSSKSVGWHWIRQSPSRGLEWLGRTYYRSRWNDDYAVSVKSRITITPDTSKNQFSLQLNSVTPEDTAVYYCARGFRYSFDYWGQGTLVTVSS (SEQ ID NO: 61).

[0066] QVQLQQSGPGLVKPSQTLSLTCAISGDSVSSNSVGWHWIRQSPSRGLEWLGRTYYRSRWNNDYAVSVKSRITITPDTSKNQFSLQLNSVTPEDTAVYYCARGFRYSFDYWGQGTLVTVSS (SEQ ID NO: 62).

[0067] QVQLQQSGPGLVKPSQTLSLTCAISGDSVSSKSVGWHWIRQSPSRGLEWLGRTYYRSKWNNDYAISVKSRITINPDTSKNQFSLQLNSVTPEDTAVYYCARGYNFGFDYWGQGTLVTVSS (SEQ ID NO: 63).

[0068] QVQLVQSGAEVKKPGSSVKVSCKASGGTFSSYAISWVRQAPGQGLEWMGIINPSGGNTRYAQKFQGRVTMTRDTATSTVYMELSSLRSEDTAMYYCARDGFGMDSSGYYRLRYWGQGTLVTVSS (SEQ ID NO: 64).

[0069] In some embodiments, the light chain variable region of the fully human antibody contains an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99% identity with any one of SEQ ID NO: 71-76.

[0070] EIVMTQTPLSLPVTPGEPASISCRSSQSLLHSNGYNYLAWYLQKPGQSPQLLIYLGSNRASGVPDRFSGSGSGTDFTLKISRVEAEDVGVYYCMQSLQTPPTFGQGTKVEIK (SEQ ID NO: 71).

[0071] EIVLTQSPLSLPVTLGQSASISCRSSHSPQFSDGNNYVSWFQQRPGQAPRLLIYRASNRASGVPDRFSGSGSGTDFTLSISGVEAEDAGTYYCMQGTHWPWTFGQGTRLEIK (SEQ ID NO: 72).

[0072] LPVLTQPPSASGTPGQRVTISSCSGSKSNIGNRTVNWYQQLPGTAPKLLIHGTDQRPSGVPDRISGSKSGTSASLAISGLQSEDEANYYCSSWDDSLKVLLFGGTKLTVL (SEQ ID NO: 73).

[0073] NFMLTQPPSASGTPGQRVTISSCSGSSSNIGSRNVNWYQQLPGTAPKLIIHSSNQRPSGVPDRYSGSKSGTSASLAISGLRSDDEAEYFCATWDDSLKVLLFGGTKLTVL (SEQ ID NO: 74).

[0074] QSVVTQPPSVSAAPGQKVTISSCSGSSSNIGKNPVSWYQHLPGAAPKLLIHDNNKRPSGIPDRFSGSKSGTSATLDITGLQTGDEADYYCATWDTKGTRLSSVGVFGGGTKVTVL (SEQ ID NO: 75).

[0075] EIVMTQTPLSSPVTLGQPASISCRSSQSLVHSDGNTYLSWLHQRPGQPPRPLIYKISNRFSGVPDRFSGSGAGTDFTLKISRVEAEDVGVYYCMQGTRFPHTFGQGTKLEIK (SEQ ID NO: 76).

[0076] In some embodiments, the fully human CCR8 antibody of the present invention comprises a heavy chain variable region and a light chain variable region, wherein the heavy chain variable region and the light chain variable region are selected from a combination of the following groups:

[0077] (1) The heavy chain variable region comprises an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99% identity with SEQ ID NO: 59, and the light chain variable region comprises an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99% identity with SEQ ID NO: 71; or

[0078] (2) The heavy chain variable region comprises an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99% identity with SEQ ID NO: 60, and the light chain variable region comprises an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99% identity with SEQ ID NO: 72; or

[0079] (3) The heavy chain variable region comprises an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99% identity with SEQ ID NO: 61, and the light chain variable region comprises an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99% identity with SEQ ID NO: 73; or

[0080] (4) The heavy chain variable region comprises an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99% identity with SEQ ID NO: 62, and the light chain variable region comprises an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99% identity with SEQ ID NO: 74; or

[0081] (5) The heavy chain variable region comprises an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99% identity with SEQ ID NO: 63, and the light chain variable region comprises an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99% identity with SEQ ID NO: 75; or

[0082] (6) The heavy chain variable region comprises an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99% identity with SEQ ID NO: 64, and the light chain variable region comprises an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99% identity with SEQ ID NO: 76.

[0083] In some embodiments, the fully human CCR8 antibody of the present invention comprises a heavy chain variable region and a light chain variable region, wherein the heavy chain variable region and the light chain variable region are selected from a combination of the following groups:

[0084] (1) The heavy chain variable region comprises the amino acid sequence shown in SEQ ID NO: 59, and the light chain variable region comprises the amino acid sequence shown in SEQ ID NO: 71; or

[0085] (2) The heavy chain variable region comprises the amino acid sequence shown in SEQ ID NO: 60, and the light chain variable region comprises the amino acid sequence shown in SEQ ID NO: 72; or

[0086] (3) The heavy chain variable region comprises the amino acid sequence shown in SEQ ID NO: 61, and the light chain variable region comprises the amino acid sequence shown in SEQ ID NO: 73; or

[0087] (4) The heavy chain variable region comprises the amino acid sequence shown in SEQ ID NO: 62, and the light chain variable region comprises the amino acid sequence shown in SEQ ID NO: 74; or

[0088] (5) The heavy chain variable region comprises the amino acid sequence shown in SEQ ID NO: 63, and the light chain variable region comprises the amino acid sequence shown in SEQ ID NO: 75; or

[0089] (6) The heavy chain variable region contains the amino acid sequence shown in SEQ ID NO: 64, and the light chain variable region contains the amino acid sequence shown in SEQ ID NO: 76.

[0090] On the other hand, the present invention provides an affinity maturation antibody, which is prepared by mutation of the fully human CCR8 antibody described in the present invention.

[0091] In some embodiments, the affinity maturation antibody comprises a heavy chain variable region and a light chain variable region, wherein the heavy chain variable region comprises complementarity-determining regions: H-CDR1, H-CDR2, and H-CDR3, and the light chain variable region comprises complementarity-determining regions: L-CDR1, L-CDR2, and L-CDR3, wherein,

[0092] The H-CDR1 has the amino acid sequence shown in X1X2X3X4S; wherein X1 is selected from P, S, G, A or R, X2 is selected from R, K, Y or S, X3 is selected from A or T, and X4 is selected from I, Y or V.

[0093] The H-CDR2 has the amino acid sequence shown in IINX5X6X7GX8TRYAQKFQG; wherein X5 is selected from P, I, K or G, X6 is selected from S, W or H, X7 is selected from G or R, and X8 is selected from N, Q, I or K;

[0094] The H-CDR3 has DX9X 10 GMDX 11 X 12 GYYRLX 13 X 14 The amino acid sequence shown; wherein, X9 is selected from G or N, X 10 Selected from F, T, or R, X 11 Selected from S or K, X 12 Selected from R or S, X 13 Selected from R or L, X 14 Selected from Y or R;

[0095] The L-CDR1 has the amino acid sequence shown in SEQ ID NO: 34, SEQ ID NO: 42, SEQ ID NO: 46, SEQ ID NO: 52 or SEQ ID NO: 56;

[0096] The L-CDR2 has the amino acid sequence shown in SEQ ID NO: 35, SEQ ID NO: 47 or SEQ ID NO: 57;

[0097] The L-CDR3 has the amino acid sequence shown in SEQ ID NO: 36, SEQ ID NO: 48 or SEQ ID NO: 58.

[0098] In some embodiments, the affinity maturation antibody comprises a heavy chain variable region and a light chain variable region, wherein the heavy chain variable region comprises complementarity-determining regions: H-CDR1, H-CDR2, and H-CDR3, and the light chain variable region comprises complementarity-determining regions: L-CDR1, L-CDR2, and L-CDR3, wherein,

[0099] The H-CDR1 has the amino acid sequence shown in SEQ ID NO: 31, SEQ ID NO: 37, SEQ ID NO: 40, SEQ ID NO: 43, SEQ ID NO: 49 or SEQ ID NO: 53;

[0100] The H-CDR2 has the amino acid sequence shown in IINX5X6X7GX8TRYAQKFQG; wherein X5 is selected from P, I, K or G, X6 is selected from S, W or H, X7 is selected from G or R, and X8 is selected from N, Q, I or K;

[0101] The H-CDR3 has DX9X 10 GMDX 11 X 12 GYYRLX 13 X 14 The amino acid sequence shown; wherein, X9 is selected from G or N, X 10 Selected from F, T, or R, X 11 Selected from S or K, X 12 Selected from R or S, X 13 Selected from R or L, X 14 Selected from Y or R;

[0102] The L-CDR1 has the amino acid sequence shown in SEQ ID NO: 34, SEQ ID NO: 42, SEQ ID NO: 46, SEQ ID NO: 52 or SEQ ID NO: 56;

[0103] The L-CDR2 has the amino acid sequence shown in SEQ ID NO: 35, SEQ ID NO: 47 or SEQ ID NO: 57;

[0104] The L-CDR3 has the amino acid sequence shown in SEQ ID NO: 36, SEQ ID NO: 48 or SEQ ID NO: 58.

[0105] In some embodiments, the affinity maturation antibody comprises a heavy chain variable region and a light chain variable region, wherein the heavy chain variable region comprises complementarity-determining regions: H-CDR1, H-CDR2, and H-CDR3, and the light chain variable region comprises complementarity-determining regions: L-CDR1, L-CDR2, and L-CDR3, wherein,

[0106] The H-CDR1 has the amino acid sequence shown in SEQ ID NO: 31, SEQ ID NO: 37, SEQ ID NO: 40, SEQ ID NO: 43, SEQ ID NO: 49 or SEQ ID NO: 53;

[0107] The H-CDR2 has the amino acid sequence shown in SEQ ID NO: 32, SEQ ID NO: 38, SEQ ID NO: 41, SEQ ID NO: 44, SEQ ID NO: 50 or SEQ ID NO: 54;

[0108] The H-CDR3 has the amino acid sequence shown in SEQ ID NO: 33, SEQ ID NO: 39, SEQ ID NO: 45, SEQ ID NO: 51 or SEQ ID NO: 55;

[0109] The L-CDR1 has the amino acid sequence shown in SEQ ID NO: 34, SEQ ID NO: 42, SEQ ID NO: 46, SEQ ID NO: 52 or SEQ ID NO: 56;

[0110] The L-CDR2 has the amino acid sequence shown in SEQ ID NO: 35, SEQ ID NO: 47 or SEQ ID NO: 57;

[0111] The L-CDR3 has the amino acid sequence shown in SEQ ID NO: 36, SEQ ID NO: 48 or SEQ ID NO: 58.

[0112] The H-CDR1 has the amino acid sequence shown in SEQ ID NO: 31, SEQ ID NO: 37, SEQ ID NO: 40, SEQ ID NO: 43, SEQ ID NO: 49 or SEQ ID NO: 53.

[0113] SYAIS (SEQ ID NO: 31).

[0114] PRAIS (SEQ ID NO: 37).

[0115] SKAYS (SEQ ID NO: 40).

[0116] GYTIS (SEQ ID NO: 43).

[0117] AYAVS (SEQ ID NO: 49).

[0118] RSAIS (SEQ ID NO: 53).

[0119] The H-CDR2 has the amino acid sequence shown in SEQ ID NO: 32, SEQ ID NO: 38, SEQ ID NO: 41, SEQ ID NO: 44, SEQ ID NO: 50 or SEQ ID NO: 54.

[0120] IINPSGGNTRYAQKFQG (SEQ ID NO: 32).

[0121] IINPSGGQTRYAQKFQG (SEQ ID NO: 38).

[0122] IINIWGGNTRYAQKFQG (SEQ ID NO: 41).

[0123] IINKSGGITRYAQKFQG (SEQ ID NO: 44).

[0124] IINPHRGNTRYAQKFQG (SEQ ID NO: 50).

[0125] IINGSGGKTRYAQKFQG (SEQ ID NO: 54).

[0126] The H-CDR3 has the amino acid sequence shown in SEQ ID NO: 33, SEQ ID NO: 39, SEQ ID NO: 45, SEQ ID NO: 51 or SEQ ID NO: 55.

[0127] DGFGMDSSGYYRLRY (SEQ ID NO: 33).

[0128] DGFGMDSRGYYRLRY (SEQ ID NO: 39).

[0129] DGTGMDKSGYYRLRY (SEQ ID NO: 45).

[0130] DNRGMDSSGYYRLRY (SEQ ID NO: 51).

[0131] DGFGMDSSGYYRLLR (SEQ ID NO: 55).

[0132] The L-CDR1 has the amino acid sequence shown in SEQ ID NO: 34, SEQ ID NO: 42, SEQ ID NO: 46, SEQ ID NO: 52 or SEQ ID NO: 56.

[0133] RSSQSLVHSDGNTYLS (SEQ ID NO: 34).

[0134] RSSQSLVHSNGNTYLS (SEQ ID NO: 42).

[0135] RSSQSLVHSSGNTYLS (SEQ ID NO: 46).

[0136] RSSQSLVHSNGNHYLS (SEQ ID NO: 52).

[0137] RSSRSLVHSTGNTYLS (SEQ ID NO: 56).

[0138] The L-CDR2 has the amino acid sequence shown in SEQ ID NO: 35, SEQ ID NO: 47 or SEQ ID NO: 57.

[0139] KISNRFS (SEQ ID NO: 35).

[0140] RINNRFS (SEQ ID NO: 47).

[0141] KISARFM (SEQ ID NO: 57).

[0142] The L-CDR3 has the amino acid sequence shown in SEQ ID NO: 36, SEQ ID NO: 48 or SEQ ID NO: 58.

[0143] MQGTRFPHT (SEQ ID NO: 36).

[0144] MQGSRFPLT (SEQ ID NO: 48).

[0145] MQGTSFPLT (SEQ ID NO: 58).

[0146] In some embodiments, the affinity maturation antibody comprises a heavy chain variable region and a light chain variable region, the heavy chain variable region comprising complementarity-determining regions: H-CDR1, H-CDR2, and H-CDR3, and the light chain variable region comprising complementarity-determining regions: L-CDR1, L-CDR2, and L-CDR3, selected from a combination of the following:

[0147] (1) The H-CDR1, H-CDR2, and H-CDR3 respectively have the amino acid sequences shown in SEQ ID NO: 37, SEQ ID NO: 38, and SEQ ID NO: 39; and the L-CDR1, L-CDR2, and L-CDR3 respectively have the amino acid sequences shown in SEQ ID NO: 34, SEQ ID NO: 35, and SEQ ID NO: 36; or

[0148] (2) The H-CDR1, H-CDR2, and H-CDR3 respectively have the amino acid sequences shown in SEQ ID NO: 40, SEQ ID NO: 41, and SEQ ID NO: 33; and the L-CDR1, L-CDR2, and L-CDR3 respectively have the amino acid sequences shown in SEQ ID NO: 42, SEQ ID NO: 35, and SEQ ID NO: 36; or

[0149] (3) The H-CDR1, H-CDR2, and H-CDR3 respectively have the amino acid sequences shown in SEQ ID NO: 43, SEQ ID NO: 44, and SEQ ID NO: 45; and the L-CDR1, L-CDR2, and L-CDR3 respectively have the amino acid sequences shown in SEQ ID NO: 46, SEQ ID NO: 47, and SEQ ID NO: 48; or

[0150] (4) The H-CDR1, H-CDR2, and H-CDR3 have the amino acid sequences shown in SEQ ID NO: 49, SEQ ID NO: 50, and SEQ ID NO: 33, respectively; and the L-CDR1, L-CDR2, and L-CDR3 have the amino acid sequences shown in SEQ ID NO: 34, SEQ ID NO: 35, and SEQ ID NO: 36, respectively; or

[0151] (5) The H-CDR1, H-CDR2, and H-CDR3 respectively have the amino acid sequences shown in SEQ ID NO: 31, SEQ ID NO: 32, and SEQ ID NO: 51; and the L-CDR1, L-CDR2, and L-CDR3 respectively have the amino acid sequences shown in SEQ ID NO: 52, SEQ ID NO: 35, and SEQ ID NO: 36; or

[0152] (6) The H-CDR1, H-CDR2 and H-CDR3 have the amino acid sequences shown in SEQ ID NO: 53, SEQ ID NO: 54 and SEQ ID NO: 55, respectively; and the L-CDR1, L-CDR2 and L-CDR3 have the amino acid sequences shown in SEQ ID NO: 56, SEQ ID NO: 57 and SEQ ID NO: 58, respectively.

[0153] In some embodiments, the affinity maturation antibody comprises at least one of a heavy chain variable region framework region and a light chain variable region framework region, wherein at least a portion of at least one of the heavy chain variable region framework region and the light chain variable region framework region is derived from at least one of a human antibody or a mutant thereof.

[0154] In some embodiments, the heavy chain variable region framework region of the affinity maturation antibody includes: H-FR1, H-FR2, H-FR3, and H-FR4; wherein,

[0155] The H-FR1 has the amino acid sequence shown in SEQ ID NO: 83;

[0156] The H-FR2 has the amino acid sequence shown in WVRQAPGQGLEWMG (SEQ ID NO: 84);

[0157] The H-FR3 has the amino acid sequence shown in RVTMTRDTATSTVYMELSSLRSEDTAMYYCAR (SEQ ID NO: 85);

[0158] The H-FR4 has the amino acid sequence shown in WGQGTLVTVSS (SEQ ID NO: 86) or WGQGTSVTVSS (SEQ ID NO: 87).

[0159] In some embodiments, the light chain variable region framework region of the affinity maturation antibody includes: L-FR1, L-FR2, L-FR3, and L-FR4; wherein,

[0160] The L-FR1 has the amino acid sequence shown in EIVMTQTPLSSPVTLGQPASISC (SEQ ID NO: 88);

[0161] The L-FR2 has the amino acid sequence shown in WLHQRPGQPPRPLIY (SEQ ID NO: 89);

[0162] The L-FR3 has the amino acid sequence shown in SEQ ID NO: 90;

[0163] The L-FR4 has the amino acid sequence shown in FGQGTKLEIK (SEQ ID NO: 91).

[0164] In some embodiments, the variable region of the affinity maturation antibody heavy chain contains an amino acid sequence that is at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99% identical to any one of SEQ ID NO: 65-70.

[0165] QVQLVQSGAEVKKPGSSVKVSCKASGGTFSPRAISWVRQAPGQGLEWMGIINPSGGQTRYAQKFQGRVTMTRDTATSTVYMELSSLRSEDTAMYYCARDGFGMDSRGYYRLRYWGQGTSVTVSS (SEQ ID NO: 65).

[0166] QVQLVQSGAEVKKPGSSVKVSCKASGGTFSSKAYSWVRQAPGQGLEWMGIINIWGGNTRYAQKFQGRVTMTRDTATSTVYMELSSLRSEDTAMYYCARDGFGMDSSGYYRLRYWGQGTLVTVSS (SEQ ID NO: 66).

[0167] QVQLVQSGAEVKKPGSSVKVSCKASGGTFSGYTISWVRQAPGQGLEWMGIINKSGGITRYAQKFQGRVTMTRDTATSTVYMELSSLRSEDTAMYYCARDGTGMDKSGYYRLRYWGQGTSVTVSS (SEQ ID NO: 67).

[0168] QVQLVQSGAEVKKPGSSVKVSCKASGGTFSAYAVSWVRQAPGQGLEWMGIINPHRGNTRYAQKFQGRVTMTRDTATSTVYMELSSLRSEDTAMYYCARDGFGMDSSGYYRLRYWGQGTLVTVSS (SEQ ID NO: 68).

[0169] QVQLVQSGAEVKKPGSSVKVSCKASGGTFSSYAISWVRQAPGQGLEWMGIINPSGGNTRYAQKFQGRVTMTRDTATSTVYMELSSLRSEDTAMYYCARDNRGMDSSGYYRLRYWGQGTSVTVSS (SEQ ID NO: 69).

[0170] QVQLVQSGAEVKKPGSSVKVSCKASGGTFSRSAISWVRQAPGQGLEWMGIINGSGGKTRYAQKFQGRVTMTRDTATSTVYMELSSLRSEDTAMYYCARDGFGMDSSGYYRLLRWGQGTSVTVSS (SEQ ID NO: 70).

[0171] In some embodiments, the variable region of the affinity maturation antibody light chain contains an amino acid sequence that is at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99% identical to any one of SEQ ID NO: 77-82.

[0172] EIVMTQTPLSSPVTLGQPASISCRSSQSLVHSDGNTYLSWLHQRPGQPPRPLIYKISNRFSGVPDRFSGSGAGTDFTLKISRVEAEDVGVYYCMQGTRFPHTFGQGTKLEIK (SEQ ID NO: 77).

[0173] EIVMTQTPLSSPVTLGQPASISCRSSQSLVHSNGNTYLSWLHQRPGQPPRPLIYKISNRFSGVPDRFSGSGAGTDFTLKISRVEAEDVGVYYCMQGTRFPHTFGQGTKLEIK (SEQ ID NO: 78).

[0174] EIVMTQTPLSSPVTLGQPASISCRSSQSLVHSSGNTYLSWLHQRPGQPPRPLIYRINNRFSGVPDRFSGSGAGTDFTLKISRVEAEDVGVYYCMQGSRFPLTFGQGTKLEIK (SEQ ID NO: 79).

[0175] EIVMTQTPLSSPVTLGQPASISCRSSQSLVHSDGNTYLSWLHQRPGQPPRPLIYKISNRFSGVPDRFSGSGAGTDFTLKISRVEAEDVGVYYCMQGTRFPHTFGQGTKLEIK (SEQ ID NO: 80).

[0176] EIVMTQTPLSSPVTLGQPASISCRSSQSLVHSNGNHYLSWLHQRPGQPPRPLIYKISNRFSGVPDRFSGSGAGTDFTLKISRVEAEDVGVYYCMQGTRFPHTFGQGTKLEIK (SEQ ID NO: 81).

[0177] EIVMTQTPLSSPVTLGQPASISCRSSRSLVHSTGNTYLSWLHQRPGQPPRPLIYKISARFMGVPDRFSGSGAGTDFTLKISRVEAEDVGVYYCMQGTSFPLTFGQGTKLEIK (SEQ ID NO: 82).

[0178] In some embodiments, the affinity maturation antibody of the present invention comprises a heavy chain variable region and a light chain variable region, wherein the heavy chain variable region and the light chain variable region are selected from a combination of the following groups:

[0179] (1) The heavy chain variable region comprises an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99% identity with SEQ ID NO: 65, and the light chain variable region comprises an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99% identity with SEQ ID NO: 77; or

[0180] (2) The heavy chain variable region comprises an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99% identity with SEQ ID NO: 66, and the light chain variable region comprises an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99% identity with SEQ ID NO: 78; or

[0181] (3) The heavy chain variable region comprises an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99% identity with SEQ ID NO: 67, and the light chain variable region comprises an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99% identity with SEQ ID NO: 79; or

[0182] (4) The heavy chain variable region comprises an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99% identity with SEQ ID NO: 68, and the light chain variable region comprises an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99% identity with SEQ ID NO: 80; or

[0183] (5) The heavy chain variable region comprises an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99% identity with SEQ ID NO: 69, and the light chain variable region comprises an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99% identity with SEQ ID NO: 81; or

[0184] (6) The heavy chain variable region comprises an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99% identity with SEQ ID NO: 70, and the light chain variable region comprises an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99% identity with SEQ ID NO: 82.

[0185] In some embodiments, the affinity maturation antibody of the present invention comprises a heavy chain variable region and a light chain variable region, wherein the heavy chain variable region and the light chain variable region are selected from a combination of the following groups:

[0186] (1) The heavy chain variable region comprises the amino acid sequence shown in SEQ ID NO: 65, and the light chain variable region comprises the amino acid sequence shown in SEQ ID NO: 77; or

[0187] (2) The heavy chain variable region comprises the amino acid sequence shown in SEQ ID NO: 66, and the light chain variable region comprises the amino acid sequence shown in SEQ ID NO: 78; or

[0188] (3) The heavy chain variable region comprises the amino acid sequence shown in SEQ ID NO: 67, and the light chain variable region comprises the amino acid sequence shown in SEQ ID NO: 79; or

[0189] (4) The heavy chain variable region comprises the amino acid sequence shown in SEQ ID NO: 68, and the light chain variable region comprises the amino acid sequence shown in SEQ ID NO: 80; or

[0190] (5) The heavy chain variable region comprises the amino acid sequence shown in SEQ ID NO: 69, and the light chain variable region comprises the amino acid sequence shown in SEQ ID NO: 81; or

[0191] (6) The heavy chain variable region contains the amino acid sequence shown in SEQ ID NO: 70, and the light chain variable region contains the amino acid sequence shown in SEQ ID NO: 82.

[0192] In some embodiments, the fully human antibody and / or the affinity-matured antibody of the present invention comprise at least one of a heavy chain constant region and a light chain constant region, wherein at least a portion of at least one of the heavy chain constant region and the light chain constant region is derived from at least one of a human antibody or a mutant thereof.

[0193] In some implementations, both the heavy chain constant region and the light chain constant region are derived from human IgG or its mutants.

[0194] In some implementations, the heavy chain constant region is derived from human IgG1 or IgG4 or a mutant thereof.

[0195] In some implementations, the light chain constant region is derived from human Kappa or Lambda constant regions.

[0196] In some embodiments, the heavy chain constant region comprises the amino acid sequence shown in SEQ ID NO: 92.

[0197] ASTKGPSVFPLAPSSKSTSGGTAALGCLVKDYFPEPVTVSWNSGALTSGVHTFPAVLQSSGLYSLSSVVTVPSSSLGTQTYICNVNHKPSNTKVDKKVEPKSCDKTHTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEV HNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSREEMTKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHEALHNHYTQKSLSLSPGK (SEQ ID NO: 92).

[0198] In some embodiments, the constant region of the antibody light chain contains the amino acid sequence shown in SEQ ID NO: 93.

[0199] RTVAAPSVFIFPPSDEQLKSGTASVVCLLNNFYPREAKVQWKVDNALQSGNSQESVTEQDSKDSTYSLSSTLTLSKADYEKHKVYACEVTHQGLSSPVTKSFNRGEC (SEQ ID NO: 93).

[0200] In some embodiments, the fully human antibody and / or affinity-matured antibody described in this invention are monoclonal antibodies.

[0201] In some embodiments, the monoclonal fully human antibody and / or affinity-matured antibody of the present invention comprises a heavy chain and a light chain, wherein the heavy chain and light chain are selected from a combination of the following groups:

[0202] (1) The heavy chain comprises the amino acid sequence shown in SEQ ID NO: 94, and the light chain comprises the amino acid sequence shown in SEQ ID NO: 101; or

[0203] (2) The heavy chain comprises the amino acid sequence shown in SEQ ID NO: 95, and the light chain comprises the amino acid sequence shown in SEQ ID NO: 102; or

[0204] (3) The heavy chain comprises the amino acid sequence shown in SEQ ID NO: 96, and the light chain comprises the amino acid sequence shown in SEQ ID NO: 103; or

[0205] (4) The heavy chain comprises the amino acid sequence shown in SEQ ID NO: 97, and the light chain comprises the amino acid sequence shown in SEQ ID NO: 104; or

[0206] (5) The heavy chain comprises the amino acid sequence shown in SEQ ID NO: 98, and the light chain comprises the amino acid sequence shown in SEQ ID NO: 105; or

[0207] (6) The heavy chain comprises the amino acid sequence shown in SEQ ID NO: 99, and the light chain comprises the amino acid sequence shown in SEQ ID NO: 106; or

[0208] (7) The heavy chain contains the amino acid sequence shown in SEQ ID NO: 100, and the light chain contains the amino acid sequence shown in SEQ ID NO: 107.

[0209] QVQLVQSGAEVKKPGSSVKVSCKASGGTFSSYAISWVRQAPGQGLEWMGIINPSGGNTRYAQKFQGRVTMTRDTATSTVYMELSSLRSEDTAMYYCARDGFGMDSSGYYRLRYWGQGTLVTVSSASTKGPSVFPLAPSSKSTSGGTAALGCLVKDYFPEPVTVSWNSGALTSGVHTFPAVLQSSGLYSLSSVVTVPSSSLGTQTYICNVNHKPSNTKVDKKVEPKSCDKTHTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSREEMTKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHEALHNHYTQKSLSLSPGK (SEQ ID NO: 94).

[0210] EIVMTQTPLSSPVTLGQPASISCRSSQSLVHSDGNTYLSWLHQRPGQPPRPLIYKISNRFSGVPDRFSGSGAGTDFTLKISRVEAEDVGVYYCMQGTRFPHTFGQGTKLEIKRTVAAPSVFIFPPSDEQLKSGTASVVCLLNNFYPREAKVQWKVDNALQSGNSQESVTEQDSKDSTYSLSSTLTLSKADYEKHKVYACEVTHQGLSSPVTKSFNRGEC (SEQ ID NO: 101).

[0211] In the present invention, an antibody comprising the heavy chain shown in SEQ ID NO: 94 and the light chain shown in SEQ ID NO: 101 is numbered: 1H4.

[0212] QVQLVQSGAEVKKPGSSVKVSCKASGGTFSPRAISWVRQAPGQGLEWMGIINPSGGQTRYAQKFQGRVTMTRDTATSTVYMELSSLRSEDTAMYYCARDGFGMDSRGYYRLRYWGQGTSVTVSSASTKGPSVFPLAPSSKSTSGGTAALGCLVKDYFPEPVTVSWNSGALTSGVHTFPAVLQSSGLYSLSSVVTVPSSSLGTQTYICNVNHKPSNTKVDKKVEPKSCDKTHTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSREEMTKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHEALHNHYTQKSLSLSPGK (SEQ ID NO: 95).

[0213] EIVMTQTPLSSPVTLGQPASISCRSSQSLVHSDGNTYLSWLHQRPGQPPRPLIYKISNRFSGVPDRFSGSGAGTDFTLKISRVEAEDVGVYYCMQGTRFPHTFGQGTKLEIKRTVAAPSVFIFPPSDEQLKSGTASVVCLLNNFYPREAKVQWKVDNALQSGNSQESVTEQDSKDSTYSLSSTLTLSKADYEKHKVYACEVTHQGLSSPVTKSFNRGEC (SEQ ID NO: 102).

[0214] In the present invention, an antibody comprising the heavy chain shown in SEQ ID NO: 95 and the light chain shown in SEQ ID NO: 102, with the number: 1H4-1-H4.

[0215] QVQLVQSGAEVKKPGSSVKVSCKASGGTFSSKAYSWVRQAPGQGLEWMGIINIWGGNTRYAQKFQGRVTMTRDTATSTVYMELSSLRSEDTAMYYCARDGFGMDSSGYYRLRYWGQGTLVTVSSASTKGPSVFPLAPSSKSTSGGTAALGCLVKDYFPEPVTVSWNSGALTSGVHTFPAVLQSSGLYSLSSVVTVPSSSLGTQTYICNVNHKPSNTKVDKKVEPKSCDKTHTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSREEMTKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHEALHNHYTQKSLSLSPGK (SEQ ID NO: 96).

[0216] EIVMTQTPLSSPVTLGQPASISCRSSQSLVHSNGNTYLSWLHQRPGQPPRPLIYKISNRFSGVPDRFSGSGAGTDFTLKISRVEAEDVGVYYCMQGTRFPHTFGQGTKLEIKRTVAAPSVFIFPPSDEQLKSGTASVVCLLNNFYPREAKVQWKVDNALQSGNSQESVTEQDSKDSTYSLSSTLTLSKADYEKHKVYACEVTHQGLSSPVTKSFNRGEC (SEQ ID NO: 103).

[0217] In the present invention, an antibody comprising the heavy chain shown in SEQ ID NO: 96 and the light chain shown in SEQ ID NO: 103, with the number: 1H4-4H1.

[0218] QVQLVQSGAEVKKPGSSVKVSCKASGGTFSGYTISWVRQAPGQGLEWMGIINKSGGITRYAQKFQGRVTMTRDTATSTVYMELSSLRSEDTAMYYCARDGTGMDKSGYYRLRYWGQGTSVTVSSASTKGPSVFPLAPSSKSTSGGTAALGCLVKDYFPEPVTVSWNSGALTSGVHTFPAVLQSSGLYSLSSVVTVPSSSLGTQTYICNVNHKPSNTKVDKKVEPKSCDKTHTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSREEMTKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHEALHNHYTQKSLSLSPGK (SEQ ID NO: 97).

[0219] EIVMTQTPLSSPVTLGQPASISCRSSQSLVHSSGNTYLSWLHQRPGQPPRPLIYRINNRFSGVPDRFSGSGAGTDFTLKISRVEAEDVGVYYCMQGSRFPLTFGQGTKLEIKRTVAAPSVFIFPPSDEQLKSGTASVVCLLNNFYPREAKVQWKVDNALQSGNSQESVTEQDSKDSTYSLSSTLTLSKADYEKHKVYACEVTHQGLSSPVTKSFNRGEC (SEQ ID NO: 104).

[0220] In the present invention, an antibody comprising the heavy chain shown in SEQ ID NO: 97 and the light chain shown in SEQ ID NO: 104, with the number: 1H4 - 2A5.

[0221] QVQLVQSGAEVKKPGSSVKVSCKASGGTFSAYAVSWVRQAPGQGLEWMGIINPHRGNTRYAQKFQGRVTMTRDTATSTVYMELSSLRSEDTAMYYCARDGFGMDSSGYYRLRYWGQGTLVTVSSASTKGPSVFPLAPSSKSTSGGTAALGCLVKDYFPEPVTVSWNSGALTSGVHTFPAVLQSSGLYSLSSVVTVPSSSLGTQTYICNVNHKPSNTKVDKKVEPKSCDKTHTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSREEMTKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHEALHNHYTQKSLSLSPGK (SEQ ID NO: 98).

[0222] EIVMTQTPLSSPVTLGQPASISCRSSQSLVHSDGNTYLSWLHQRPGQPPRPLIYKISNRFSGVPDRFSGSGAGTDFTLKISRVEAEDVGVYYCMQGTRFPHTFGQGTKLEIKRTVAAPSVFIFPPSDEQLKSGTASVVCLLNNFYPREAKVQWKVDNALQSGNSQESVTEQDSKDSTYSLSSTLTLSKADYEKHKVYACEVTHQGLSSPVTKSFNRGEC (SEQ ID NO: 105).

[0223] In the present invention, an antibody comprising the heavy chain shown in SEQ ID NO: 98 and the light chain shown in SEQ ID NO: 105, is numbered: 1H4-3D2.

[0224] QVQLVQSGAEVKKPGSSVKVSCKASGGTFSSYAISWVRQAPGQGLEWMGIINPSGGNTRYAQKFQGRVTMTRDTATSTVYMELSSLRSEDTAMYYCARDNRGMDSSGYYRLRYWGQGTSVTVSSASTKGPSVFPLAPSSKSTSGGTAALGCLVKDYFPEPVTVSWNSGALTSGVHTFPAVLQSSGLYSLSSVVTVPSSSLGTQTYICNVNHKPSNTKVDKKVEPKSCDKTHTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSREEMTKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHEALHNHYTQKSLSLSPGK (SEQ ID NO: 99).

[0225] EIVMTQTPLSSPVTLGQPASISCRSSQSLVHSNGNHYLSWLHQRPGQPPRPLIYKISNRFSGVPDRFSGSGAGTDFTLKISRVEAEDVGVYYCMQGTRFPHTFGQGTKLEIKRTVAAPSVFIFPPSDEQLKSGTASVVCLLNNFYPREAKVQWKVDNALQSGNSQESVTEQDSKDSTYSLSSTLTLSKADYEKHKVYACEVTHQGLSSPVTKSFNRGEC (SEQ ID NO: 106).

[0226] In the present invention, an antibody comprising the heavy chain shown in SEQ ID NO: 99 and the light chain shown in SEQ ID NO: 106, with the number: 1H4-5B4.

[0227] QVQLVQSGAEVKKPGSSVKVSCKASGGTFSRSAISWVRQAPGQGLEWMGIINGSGGKTRYAQKFQGRVTMTRDTATSTVYMELSSLRSEDTAMYYCARDGFGMDSSGYYRLLRW GQGTSVTVSSASTKGPSVFPLAPSSKSTSGGTAALGCLVKDYFPEPVTVSWNSGALTSGVHTFPAVLQSSGLYSLSSVVTVPSSSLGTQTYICNVNHKPSNTKVDKKVEPKSCDK THTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTI SKAKGQPREPQVYTLPPSREEMTKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHEALHNHYTQKSLSLSPGK (SEQ ID NO: 100).

[0228] EIVMTQTPLSSPVTLGQPASISCRSSRSLVHSTGNTYLSWLHQRPGQPPRPLIYKISARFMGVPDRFSGSGAGTDFTLKISRVEAEDVGVYYCMQGTSFPLTFGQGTKLEI KRTVAAPSVFIFPPSDEQLKSGTASVVCLLNNFYPREAKVQWKVDNALQSGNSQESVTEQDSKDSTYSLSSTLTLSKADYEKHKVYACEVTHQGLSSPVTKSFNRGEC (SEQ ID NO: 107).

[0229] In this invention, an antibody comprising the heavy chain shown in SEQ ID NO: 100 and the light chain shown in SEQ ID NO: 107 is designated as 1H4-2D8.

[0230] In some embodiments, the antigen-binding fragments described in this invention are selected from: Fab, Fab', Fv, sdFv, and (Fab')2.

[0231] Fab consists of a complete light chain, a variable region domain (VH) of the heavy chain, and a first constant domain (CH1) of the heavy chain. Fab can be a product of antibody digestion by papain. Fab' differs from Fab in that the Fab' fragment has some residues added to the carboxyl terminus of the CH1 domain. These residues include one or more cysteine ​​residues missing from the hinge region of the antibody. (Fab')2 is equivalent to two Fab' fragments linked by disulfide bonds, which have divalent antigen-binding activity and can still crosslink antigens. (Fab')2 can be a product of antibody cleavage by pepsin. Fv consists of a tight, non-covalently associated dimer of a heavy chain variable region domain and a light chain variable region domain. sdFv refers to an Fv fragment linked by disulfide bonds.

[0232] In some embodiments, the antibody described in this invention is a natural intact antibody, a single-chain antibody (scFv), a single-chain Fv-Fc antibody (scFv-Fc), a scFv dimer, and a dimer of a scFv-Fc antibody. The dimer includes homodimers and heterodimers.

[0233] The single-chain antibody (scFv) described above comprises a heavy chain variable region (VH) with the amino acid sequence shown in any one of SEQ ID NO: 59-70 and a light chain variable region (VL) with the amino acid sequence shown in any one of SEQ ID NO: 71-82. The C-terminus of the heavy chain variable region is connected to the N-terminus of the light chain variable region via a linker, or the C-terminus of the variable region is connected to the N-terminus of the heavy chain variable region via a linker. It should be noted that the "linker" of the single-chain antibody described in this invention is used to connect the heavy chain variable region and the light chain variable region of the antibody. It can be a commonly used linker for preparing single-chain antibodies, or a linker modified by researchers. An example of the amino acid sequence of the linker is: (GnS)m, where n is a natural number from 3 to 5, preferably 4, and m is a natural number from 1 to 5, preferably 3.

[0234] A specific example of a linker peptide is: GGGGSGGGGSGGGGS (SEQ ID NO: 108).

[0235] Specifically, the single-chain antibody (scFv) of the present invention comprises a heavy chain variable region, a light chain variable region, and a Linker: VH-Linker-VL.

[0236] As a specific example, the single-chain antibody (scFv) of the present invention comprises the amino acid sequence shown in SEQ ID NO: 109.

[0237] QVQLQQSGPGLVRPSQTLSLTCAISGDSISSSSAAWSWIRQSPSGGLEWLGRTYYRSKWRSDYAVSVKSRISVTPDTSKNQFSLQLNSVTPEDTAKYFCARGRWSGFDIWGQGTMVTVSSGGGGS GGGGSGGGGSEIVMTQTPLSLPVTPGEPASISCRSSQSLLHSNGYNYLAWYLQKPGQSPQLLIYLGSNRASGVPDRFSGSGSGTDFTLKISRVEAEDVGVYYCMQSLQTPPTFGQGTKVEIK (SEQ ID NO: 109).

[0238] As shown in the amino acid sequence of SEQ ID NO: 109, the bolded part is the linker peptide.

[0239] The single-chain antibodies described in this invention can all be constructed with reference to the specific examples described above.

[0240] The single-chain Fv-Fc antibody (scFv-Fc) described above comprises an scFv and an Fc fragment, wherein the Fc fragment is a constant region fragment of the antibody heavy chain containing at least a hinge region, CH2 and CH3 domains; the scFv, as described above, is directly linked to the Fc fragment or linked via a linker (specific examples of linkers include GGGGSGGGGSGGGGS). In some embodiments, the scFv and Fc fragment are directly linked via the hinge region.

[0241] The Fc fragment described above is derived from, for example, the heavy chain constant region selected from human IgG1, IgG2, IgG3, IgG4, IgM, IgA1, IgA2, IgD, and IgE; particularly selected from, for example, the heavy chain constant region selected from human IgG1, IgG2, IgG3, and IgG4, and more particularly selected from the heavy chain constant region selected from human IgG1 or IgG4; and the Fc fragment has one or more amino acid substitutions, deletions, or additions (e.g., up to 20, up to 15, up to 10, up to 5, up to 3, or up to 1 substitution, deletion, or addition) compared to its derived natural sequence.

[0242] Specifically, the Fc in the single-chain Fv-Fc antibody (scFv-Fc) of the present invention has the amino acid sequence shown in SEQ ID NO: 110.

[0243] EPKSCDKTHTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIE KTISKAKGQPREPQVYTLPPSREEMTKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHEALHNHYTQKSLSLSPGK (SEQ ID NO: 110).

[0244] In the single-chain Fv-Fc antibody (scFv-Fc) of the present invention, the scFv can be constructed with reference to the specific examples of single-chain antibodies described above, and the Fc has the amino acid sequence described above.

[0245] Specifically, the single-chain Fv-Fc antibody (scFv-Fc) of this invention further comprises a linker. The linker can be a commonly used linker for antibody preparation, or a linker modified by researchers. The linker is used to link scFv and Fc, wherein the C-terminus of the scFv is linked to the N-terminus of the Fc via the linker. An example of the amino acid sequence of the linker is: GGGGSGGGGSGGGGS (SEQ ID NO: 108).

[0246] Specifically, the single-chain Fv-Fc antibody (scFv-Fc) of the present invention comprises scFv, Fc and Linker: scFv-Linker-Fc.

[0247] As a specific example, the single-chain Fv-Fc antibody (scFv-Fc) of the present invention contains the amino acid sequence shown in SEQ ID NO: 111.

[0248] QVQLQQSGPGLVRPSQTLSLTCAISGDSISSSSAAWSWIRQSPSGGLEWLGRTYYRSKWRSDYAVSVKSRISVTPDTSKNQFSLQLNSVTPEDTAKYFCARGRWSGFDIWGQGTMVTVSSGGGG SGGGGSGGGGSEIVMTQTPLSLPVTPGEPASISCRSSQSLLHSNGYNYLAWYLQKPGQSPQLLIYLGSNRASGVPDRFSGSGSGTDFTLKISRVEAEDVGVYYCMQSLQTPPTFGQGTKVEIKGG GGSGGGGSGGGGSEPKSCDKTHTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNK ALPAPIEKTISKAKGQPREPQVYTLPPSREEMTKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHEALHNHYTQKSLSLSPGK (SEQ ID NO: 111).

[0249] The single-chain Fv-Fc antibody (scFv-Fc) described in this invention can be constructed with reference to the specific examples described above.

[0250] In some embodiments, the antibodies described in this invention can mediate antibody-dependent cytotoxicity and / or antibody-dependent phagocytosis (ADCC and / or ADCP) and block the CCR8 and CCL1 signaling pathways.

[0251] In some embodiments, the fully human antibody and / or affinity-matured antibody described in this invention are monospecific antibodies, bispecific antibodies, or multispecific antibodies.

[0252] On the other hand, the present invention provides a chimeric antigen receptor comprising the fully human antibody and / or affinity-matured antibody described in the present invention.

[0253] On the other hand, the present invention provides a genetically modified cell that contains the chimeric antigen receptor.

[0254] In some implementations, the genetically modified cells are immune cells, such as T cells or NK cells.

[0255] On the other hand, the present invention provides an antibody-drug conjugate comprising the fully human antibody and / or affinity-matured antibody described in the present invention.

[0256] On the other hand, the present invention provides an isolated nucleic acid molecule comprising a nucleotide sequence encoding the fully human antibody and / or affinity-matured antibody described in the present invention.

[0257] In some embodiments, the nucleic acid molecule is intended to include DNA and RNA molecules. The nucleic acid molecule can be single-stranded or double-stranded, and can be cDNA.

[0258] On the other hand, the present invention provides an expression vector carrying the nucleic acid molecule described in the present invention.

[0259] In some embodiments, the expression vector of the present invention is selected from plasmids, granules, viruses, mini-chromosomes, and artificial chromosomes.

[0260] In some embodiments, the expression vector of the present invention is a eukaryotic expression vector.

[0261] In some embodiments, the eukaryotic expression vector of the present invention is selected from: pCRII, pCR3 and pcDNA3.4, pBSII, pET 15, pGEX, pEGFP-N1, pETL, pDSR-α and pFastBacDual, etc.

[0262] On the other hand, the present invention provides a nucleic acid construct comprising the nucleic acid molecule described in the present invention; further, the nucleic acid construct comprises one or more control sequences operatively linked to the nucleic acid molecule, wherein the one or more control sequences direct the production of the antibody or its antigen-binding fragment described in the present invention in a suitable host cell, and the one or more control sequences are selected from: promoters, enhancers, stop signals, signal peptides, leader sequences, transcription terminators and any group thereof.

[0263] On the other hand, the present invention provides a host cell containing the nucleic acid molecule or expression vector described in the present invention.

[0264] In some embodiments, the host cell of the present invention is Escherichia coli, yeast, or eukaryotic cell.

[0265] In some embodiments, the host cell described in this invention is a eukaryotic host cell.

[0266] In some implementations, the host cell is a mammalian host cell.

[0267] On the other hand, the present invention provides a pharmaceutical composition comprising the fully human antibody or antigen-binding fragment described in the present invention, the affinity maturation antibody described in the present invention, the nucleic acid molecule described in the present invention, the expression vector described in the present invention, the host cell described in the present invention, and a pharmaceutically acceptable vector.

[0268] On the other hand, the present invention provides the use of the fully human antibody or antigen-binding fragment described in the present invention, the affinity maturation antibody described in the present invention, the nucleic acid molecule described in the present invention, the expression vector described in the present invention, the host cell described in the present invention, or the pharmaceutical composition described in the present invention in the preparation of a drug, the drug being used to prevent, alleviate, and / or treat CCR8-related diseases or CCR8-CCL1 pathway-related diseases.

[0269] In some embodiments, the CCR8-related diseases or CCR8-CCL1 pathway-related diseases described in this invention include tumors, wherein the tumors are selected from breast cancer, kidney cancer, pancreatic cancer, bladder cancer, gastric cancer, cervical cancer, colon cancer, metastatic brain cancer, metastatic liver cancer, etc.

[0270] On the other hand, the present invention provides a method for preventing, alleviating and / or treating CCR8-related diseases or CCR8-CCL1 pathway-related diseases, the method comprising administering to a subject in need a fully human antibody or antigen-binding fragment of the present invention, an affinity maturation antibody of the present invention, a nucleic acid molecule of the present invention, an expression vector of the present invention, a host cell of the present invention or a pharmaceutical composition of the present invention.

[0271] On the other hand, the present invention provides a kit comprising the fully human antibody or antigen-binding fragment described in the present invention and / or the affinity maturation antibody described in the present invention, as well as instructions for use.

[0272] Terminology Definition

[0273] In this invention, unless otherwise stated, the scientific and technical terms used herein have the meanings commonly understood by those skilled in the art. Furthermore, the operational steps used herein, such as cell culture, molecular biology, biochemistry, nucleic acid chemistry, and immunology, are all conventional steps widely used in their respective fields. To better understand this invention, definitions and explanations of relevant terms are provided below.

[0274] When the terms “for example,” “such as,” “like,” “including,” “contains,” or variations thereof are used herein, these terms will not be considered restrictive terms but will be interpreted as meaning “but not limited to” or “not limited to.”

[0275] Unless otherwise specified herein or clearly contradicted by the context, the terms “an” and “a kind” as well as “the” and similar designations shall be interpreted to cover both the singular and plural in the context of describing the invention.

[0276] As used in this article, “CCR8”, “CC chemokine receptor type 8”, and “chemokine receptor 8” refer to any native CCR8 or a variant of native CCR8 produced by the expression and processing of CCR8 in cells.

[0277] As used in this article, “CCL1” and “CC motif chemokine 1” refer to any natural CCR1 or a variant of natural CCR1 produced by the expression and processing of CCR1 in cells.

[0278] The term "specifically binds" to an antigen or epitope is well known in the art, as are methods for determining such specific binding. A molecule is said to exhibit "specific binding" or "preferential binding" if it reacts or associates with a particular cell or substance more frequently, more rapidly, for a longer duration, and / or with a greater affinity than it does with alternative cells or substances. An antibody is said to "specifically bind" or "preferentially bind" to a target if it binds to it with a greater affinity, stronger affinity, easier binding, and / or for a longer duration than it binds to other substances. For example, an antibody that specifically or preferentially binds to a CCR8 epitope is an antibody that binds to that epitope with a greater affinity, stronger affinity, easier binding, and / or for a longer duration than it binds to other CCR8 epitopes or non-CCR8 epitopes.

[0279] As used herein, the term "epitope" refers to a site on a target molecule (e.g., an antigen, such as a protein, nucleic acid, carbohydrate, or lipid) to which an antigen-binding molecule (e.g., an antibody, antibody fragment, or scaffold protein containing an antibody-binding region) binds. Epitopes typically include chemically active surface groups of a molecule, such as amino acid, polypeptide, or sugar side chains, and possess specific three-dimensional structural features and specific charge characteristics. Epitopes can be formed from both continuous residues and / or juxtaposed non-continuous residues (e.g., amino acid, nucleotide, sugar, lipid moieties) of the target molecule.

[0280] The term “antibody” is used in the broadest sense and covers a wide range of antibody structures, including but not limited to monoclonal antibodies, polyclonal antibodies, multispecific antibodies (e.g., bispecific (such as bispecific T cell adaptors) and trispecific antibodies) and antibody fragments, as long as they exhibit the desired antigen-binding activity.

[0281] The term "monoclonal antibody" refers to an antibody that is a substantially homogeneous group of antibodies; that is, the individual antibodies that make up this group are identical, except for the possibility of naturally occurring mutations present in small quantities. Monoclonal antibodies are highly specific, targeting a single antigenic site. Furthermore, unlike polyclonal antibody preparations, which typically consist of different antibodies targeting different determinants (epitopes), each monoclonal antibody targets a single determinant on the antigen. Therefore, a monoclonal antibody sample can bind to the same epitope on the antigen. The modifier "monoclonal" indicates the characteristic of antibodies obtained from a substantially homogeneous group of antibodies and should not be interpreted as requiring the production of antibodies by any particular method.

[0282] The term "complementarity-determining region" or "CDR" refers to the amino acid residue in the variable region of an antibody responsible for antigen binding. The term "CDR" signifies a complementarity-determining region as defined by a person skilled in the art through at least one identification method. In some embodiments, the CDR can be defined according to any Chothia numbering scheme, Kabat numbering scheme, combination of Kabat and Chothia, AbM definition, Contact definition, and / or combination of Kabat, Chothia, AbM, and / or Contact definitions. The CDR of this invention is defined according to the Kabat numbering scheme.

[0283] The term "heavy chain variable region (VH)" refers to a region containing at least three heavy chain CDRs. In some embodiments, the heavy chain variable region includes three CDRs and at least FR2 and FR3. In some embodiments, the heavy chain variable region includes at least heavy chain HCDR1, frame (FR)2, HCDR2, FR3, and HCDR3. In some embodiments, the heavy chain variable region also includes at least a portion of FR1 and / or at least a portion of FR4.

[0284] The term "frame region" or "FR" residues refers to the amino acid residues in the antibody variable region other than the CDR residues as defined above.

[0285] The term "heavy chain constant region" refers to a region containing at least three heavy chain constant regions CH1, CH2, and CH3. Of course, unless otherwise specified, the absence and alteration of non-functional changes within a domain are covered by the term "heavy chain constant region."

[0286] The term "heavy chain" refers to a polypeptide containing at least one heavy chain variable region, with or without a leader sequence. In some embodiments, the heavy chain contains at least a portion of the heavy chain constant region. As used herein, the term "full-length heavy chain" refers to a polypeptide containing both a heavy chain variable region and a heavy chain constant region, with or without a leader sequence.

[0287] The term "light chain variable region (VL)" refers to a region containing at least three light chain CDRs. In some embodiments, the light chain variable region contains three CDRs and at least FR2 and FR3. In some embodiments, the light chain variable region contains at least light chains LCDR1, frame (FR)2, LCDR2, FR3, and LCDR3. For example, the light chain variable region may contain light chains CDR1, frame (FR)2, CDR2, FR3, and CDR3. In some embodiments, the light chain variable region also contains at least a portion of FR1 and / or at least a portion of FR4.

[0288] The term "light chain constant region" refers to the region containing the light chain constant structural domain CL. Non-limiting exemplary light chain constant regions include λ and κ. Of course, unless otherwise specified, the absence and alteration of non-functional changes within the structural domain are covered within the scope of the term "light chain constant region".

[0289] The term "light chain" refers to a polypeptide containing at least one light chain variable region and having or not having a leader sequence. In some embodiments, the light chain contains at least a portion of a light chain constant region. As used herein, the term "full-length light chain" refers to a polypeptide containing both a light chain variable region and a light chain constant region and having or not having a leader sequence.

[0290] The term "amino acid" refers to a compound containing both amino and carboxyl functional groups, such as α-amino acids. Two or more amino acids can form a polypeptide through an amide bond (also known as a peptide bond). A single amino acid is encoded by a nucleic acid consisting of three nucleotides (so-called a codon or base triplet). Each amino acid is encoded by at least one codon. The fact that the same amino acid is encoded by different codons is called "degeneracy of the genetic code." Amino acids include both natural and non-natural amino acids. Natural amino acids include alanine (three-letter code: Ala, one-letter code: A), arginine (Arg, R), asparagine (Asn, N), aspartic acid (Asp, D), cysteine ​​(Cys, C), glutamine (Gln, Q), glutamic acid (Glu, E), glycine (Gly, G), histidine (His, H), isoleucine (Ile, I), leucine (Leu, L), lysine (Lys, K), methionine (Met, M), phenylalanine (Phe, F), proline (Pro, P), serine (Ser, S), threonine (Thr, T), tryptophan (Trp, W), tyrosine (Tyr, Y), and valine (Val, V).

[0291] The term "affinity-matured" antibody refers to an antibody that has one or more amino acid residues altered in one or more CDRs compared to a parent antibody without the alteration, such alteration resulting in improved affinity of the antibody for the antigen.

[0292] The term "fully human antibody" refers to an antibody whose entire gene sequence is derived from human antibody genes. It is typically obtained through transgenic animals, in vitro construction of a fully human antibody library using surface display technology, or isolation from human single-cell B cells. Fully human antibodies can significantly reduce the immune side effects caused by heterologous antibodies.

[0293] "Antibody-dependent cell-mediated cytotoxicity" or "ADCC" refers to a form of cytotoxicity in which secreted Ig binds to Fc receptors (FcRs) present on certain cytotoxic cells (e.g., 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.

[0294] Antibody-dependent cell-mediated phagocytosis (ADCP) is a process by which effector cells with phagocytic potential (e.g., macrophages, monocytes, neutrophils) endocytose target cells (e.g., tumor cells). Antibodies bind to target cells by recognizing their antigens, and then bind phagocytes to their Fc fragments on the target cells. Once the target cell binds to the Fc receptor (FcR) of the phagocyte, it is phagocytosed. The phagosomes fuse with lysosomes and are degraded. This process also leads to the production of soluble factors by effector cells, which help initiate and drive the immune response.

[0295] "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 of the complement system (C1q) to an antibody (of the appropriate subclass) that binds to its homologous antigen.

[0296] The term "regulatory T cells" (also known as "Tregs" or "suppressive T cells") refers to an immunosuppressive subset of T cells that typically suppress or downregulate the induction and proliferation of effector T cells. Tregs express CD4, FOXP3, and CD25 (the α chain of the IL-2 receptor). Compared to Tregs in healthy subjects, Tregs derived from cancer patients are typically characterized by a unique expression profile of chemokine receptors such as CCR4, CXCR4, and CCR5, which facilitate their migration into the tumor in response to corresponding chemokine ligands from the tumor microenvironment.

[0297] The term "antibody-drug conjugate (ADC)" refers to the conjugation of an antibody to an effector molecule, preferably a chemical conjugation. The effector molecule is preferably a drug with therapeutic activity, such as one or more of a toxic protein, chemotherapeutic agent, small molecule drug, or radionuclide.

[0298] "Isolated" proteins or peptides are those that have been separated from components of their natural environment. In some aspects, proteins or peptides are purified to a purity greater than 95% or 99% by means of, for example, electrophoresis (e.g., SDS-PAGE, isoelectric focusing (IEF), capillary electrophoresis) or chromatography (e.g., ion exchange or reversed-phase HPLC). "Isolated" nucleic acids refer to nucleic acid molecules that have been separated from components of their natural environment. Isolated nucleic acids include nucleic acid molecules contained in cells that normally contain said nucleic acid molecules, but which are located extrachromosomally or at chromosomal locations different from their natural chromosomal locations.

[0299] The term "expression vector" refers to a nucleic acid delivery vehicle into which polynucleotides can be inserted. When a vector enables the expression of a protein encoded by the inserted polynucleotide, it is called an expression vector. Vectors can be introduced into host cells through transformation, transduction, or transfection, allowing the genetic material elements they carry to be expressed in the host cells. Vectors are well-known to those skilled in the art and include, but are not limited to: plasmids; phage particles; Cos plasmids; 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 papillomaviruses (such as SV40). A vector may contain multiple elements controlling expression, including but not limited to, promoter sequences, transcription initiation sequences, enhancer sequences, selection elements, and reporter genes. Additionally, the vector may contain a replication initiation site.

[0300] The term "nucleic acid molecule" is intended to include both DNA and RNA molecules. Nucleic acid molecules can be single-stranded or double-stranded, and can be cDNA.

[0301] The term "host cell" refers to any cell that can be used to introduce a vector, including but not limited to prokaryotic cells such as *Escherichia coli* or *Bacillus subtilis*, fungal cells such as yeast cells or *Aspergillus*, insect cells such as S2 *Drosophila* cells or Sf9 cells, or animal cells such as fibroblasts, CHO cells, COS cells, NSO cells, HeLa cells, BHK cells, HEK 293 cells, or human cells. Host cells can include single cells or populations of cells.

[0302] The term "identity" is used to refer to the sequence matching between two polypeptides or two nucleic acids. Two compared sequences are considered identical at that position when a position is occupied by the same base or amino acid monomer subunit (e.g., a position in each of two DNA molecules is occupied by adenine, or a position in each of two polypeptides is occupied by lysine). The "percentage identity" between two sequences is a function of the number of matching positions shared by the two sequences divided by the number of positions compared × 100. For example, if six out of ten positions in two sequences match, then the two sequences are 60% identical. Typically, two sequences are compared to produce the maximum identity. Such comparisons can be performed conveniently using, for example, computer programs such as the Align program (DNAstar, Inc.) Needleman et al. (1970) J. Mol. Biol. 48: 443-453. The percentage identity between two amino acid sequences can also be determined using the algorithm of E. Meyers and W. Miller (Comput. Appl Biosci., 4:11-17 (1988)) integrated into the ALIGN program (version 2.0), which uses a PAM120 weight residue table, a gap length penalty of 12, and a gap penalty of 4. Alternatively, the percentage identity between two amino acid sequences can be determined using the Needleman and Wunsch algorithm (J MoIBiol. 48:444-453 (1970)) in the GAP program integrated into the GCG software package (available at www.gcg.com), which uses a Blossum 62 matrix or a PAM250 matrix, along with gap weights of 16, 14, 12, 10, 8, 6, or 4, and length weights of 1, 2, 3, 4, 5, or 6.

[0303] The term "pharmaceutically acceptable carrier" refers to a carrier that is pharmacologically and / or physiologically compatible with the subject and the active ingredient, which is well known in the art (see, for example, Remington's Pharmaceutical Sciences. Edited by Gennaro AR, 19th ed. Pennsylvania: Mack Publishing Company, 1995), and includes, but is not limited to: pH adjusters, surfactants, adjuvants, ionic strength enhancers, diluents, osmotic pressure maintaining agents, absorption delay agents, and preservatives. 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. Ionic strength enhancers include, but are not limited to, sodium chloride. Preservatives include, but are not limited to, various antibacterial and antifungal agents, such as parabens, chlorobutanol, phenol, sorbic acid, etc. Osmotic pressure maintaining agents include, but are not limited to, sugars, NaCl, and their analogues. Absorption delay agents include, but are not limited to, monostearates and gelatin. Diluents include, but are not limited to, water, aqueous buffers (such as buffered saline), alcohols, and polyols (such as glycerol). Preservatives include, but are not limited to, various antibacterial and antifungal agents, such as thimerosal, 2-phenoxyethanol, parabens, chlorobutanol, phenol, sorbic acid, etc. Stabilizers have the meaning commonly understood by those skilled in the art for stabilizing the desired activity of the active ingredient in the pharmaceutical product, including, but not limited to, monosodium glutamate, gelatin, SPGA, sugars (such as sorbitol, mannitol, starch, sucrose, lactose, dextran, or glucose), amino acids (such as glutamic acid, glycine), proteins (such as dried whey, albumin, or casein) or their degradation products (such as lactalbumin hydrolysate), etc. In some exemplary embodiments, the pharmaceutically acceptable carrier includes sterile injectable liquids (such as aqueous or non-aqueous suspensions or solutions). In some exemplary embodiments, such sterile injectable fluids are selected from water for injection (WFI), antibacterial water for injection (BWFI), sodium chloride solution (e.g., 0.9% (w / v) NaCl), glucose solution (e.g., 5% glucose), solution containing surfactant (e.g., 0.01% polysorbate 20), pH buffer solution (e.g., phosphate buffer solution), Ringer's solution, and any combination thereof.

[0304] The term "subject" generally refers to mammals. Mammals include, but are not limited to, domesticated animals (such as cows, sheep, cats, dogs, and horses), primates (such as humans and non-human primates, such as monkeys), rabbits, and rodents (such as mice and rats).

[0305] The term "tumor" generally refers to all proliferative cell growth and proliferation (whether malignant or benign) as well as all precancerous and cancerous cells and tissues. In this application, a tumor may include solid tumors and / or non-solid tumors (e.g., hematologic malignancies, lymphomas).

[0306] The term "administration" means a method of giving a subject a dose of a compound (e.g., the anti-CCR8 antibody of the present invention). In some aspects, the compositions used in the methods described herein are administered intravenously. The compositions used in the methods described herein may be administered, for example, intramuscularly, intravenously, subcutaneously, percutaneously, intra-arterially, intraperitoneally, intralesionally, intracranially, intra-articularly, intra-articularly, intraprostatically, intrapleurally, intratracheally, intranasally, intravitreally, intravaginally, intrarectally, topically, intratumorally, intraperitoneally, intraperitoneally, subcutaneously, subconjunctivally, intracysticly, intraarticularly, intra- ... or intra-articularly, orally, or topically, locally, by inhalation, by injection, by infusion, by continuous infusion, by local perfusion directly irrigating target cells, by catheter, by irrigation, or in the form of an emulsion or lipid composition. The method of administration can vary depending on a variety of factors (e.g., the compound or composition to be administered and the severity of the condition, disease, or ailment to be treated).

[0307] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings and examples. However, those skilled in the art will understand that the following drawings and examples are for illustrative purposes only and are not intended to limit the scope of the invention. Various objects and advantages of the present invention will become apparent to those skilled in the art from the following detailed description of the drawings and preferred embodiments. Attached Figure Description

[0308] Figure 1 This is a diagram showing the binding results of some positive bacteriophages to CHO-CCR8 cells in Example 1;

[0309] Figure 2 This is a diagram showing the binding results of the antibody with the CHO-hCCR8 cell line in Example 3;

[0310] Figure 3 This is a diagram showing the binding results of the antibody with the 293T-mCCR8 cell line in Example 3;

[0311] Figure 4 This is a diagram showing the binding results of the antibody with the 293T-cynCCR8 cell line in Example 3;

[0312] Figure 5 This is a diagram showing the binding results of the antibody with the 293T-hCCR4 cell line in Example 3;

[0313] Figure 6This is a diagram showing the binding results of the antibody with the 293T cell line in Example 3;

[0314] Figure 7 This is a diagram showing the binding results of the antibody to the CHO cell line in Example 3;

[0315] Figure 8 This is a graph showing the binding ability of the antibody to CHO-hCCR8 in Example 4;

[0316] Figure 9 This is a graph showing the binding ability of the affinity-mature mutant to CHO-hCCR8 in Example 5;

[0317] Figure 10 This is a graph showing the ADCC effect results of the affinity-mature mutant in Example 6. Detailed Implementation

[0318] The present invention will be explained below with reference to embodiments. Those skilled in the art will understand that the following embodiments are for illustrative purposes only and should not be considered as limiting the scope of the invention. Where specific techniques or conditions are not specified in the embodiments, they are performed according to the techniques or conditions described in the literature in the field or according to the product instructions. Reagents or instruments whose manufacturers are not specified are all conventional products that can be obtained commercially.

[0319] Unless otherwise specified, the molecular biology experimental methods and immunoassays used in this invention are substantially in accordance with the methods described in J. Sambrook et al., Molecular Cloning: A Laboratory Manual, 2nd Edition, Cold Spring Harbor Laboratory Press, 1989, and F.M. Ausubel et al., A Concise Guide to Molecular Biology, 3rd Edition, John Wiley & Sons, Inc., 1995. Those skilled in the art will appreciate that the examples illustrate the invention by way of illustration and are not intended to limit the scope of the invention as claimed.

[0320] Example 1: Generation of antibodies binding to CCR8

[0321] Specific antibody clones targeting CCR8 were enriched from a fully human phage library using affinity panning. Monoclonal antibody strains capable of binding to the CCR8 protein at the phage level were screened using flow cytometry. The extracellular region coding gene for the CCR8 protein was designed using the NCBI database and constructed into a mammalian eukaryotic expression system to express the extracellular loop1 and loop2 proteins of the CCR8 protein, which were then used for phage antibody library screening. Multiple rounds of panning were performed on the fully human phage library using loop1-Fc and loop2-Fc as panning proteins to obtain a phage pool enriched with the target antibody clones. Using different antibody libraries, three rounds of protein panning were conducted, and a significant increase in recovery rate was observed in each panning. The collected phage pools were then used for further monoclonal selection and ELISA / FACS screening.

[0322] To obtain specific clones, single clones need to be isolated and packaged into single-clone phages. Initial screening is performed using enzyme-linked immunosorbent assay (ELISA), and DNA sequencing is used to determine the unique antibody sequence contained within. The sequenced unique antibody sequence is then further analyzed using flow cytometry (FACS). ELISA results are shown in Tables 1-3. Phages 1G3 and 1H4 showed strong binding to both loop 1-Fc and loop 2-Fc, while phages 2G12, 5D6, 5G6, and 8H7 showed strong binding to loop 1-Fc and weak binding to loop 2-Fc. None of the above phages bound to Fc. FACS binding is as follows: Figure 1 As shown, the peaks of phages 1G3, 1H4, 2G12, 5D6, 5G6, and 8H7 are shifted to the right compared to the negative control (NC), indicating that these phages bind to the overexpressing cell line CHO-hCCR8. Figure 1 1G3, 1H4, 2G12, 5D6, 5G6 and 8H7 were all phage supernatants in scFv form.

[0323] Table 1. ELISA results of partial positive bacteriophage binding to loop1-Fc

[0324]

[0325] Table 2. ELISA results of partial positive bacteriophage binding to loop2-Fc

[0326]

[0327] Table 3. Results of ELISA assay for binding of some positive bacteriophages to Fc.

[0328]

[0329] Example 2: Expression, purification, and identification of antibodies

[0330] A series of antibody expression vectors were constructed using molecular cloning methods and recombinantly expressed in the 293F expression system. The nucleotide sequences encoding the light and heavy chains of a series of monoclonal antibodies were obtained by extracting plasmids from panning phage cultures. The obtained scFv sequences were double-digested and inserted into the same restriction sites of eukaryotic expression vectors to construct a series of antibody expression vectors. Then, a series of validated expression vectors were extracted using an Invitrogen plasmid extraction kit, linearized with restriction endonucleases, purified, and recovered, and stored at -20°C.

[0331] After reviving and culturing 293F host cells in OPMA medium, when the cell density was approximately 3*10⁻⁶, 6 Cells were collected at a concentration of 1000 cells / mL and transfected using PEI reagent. On the second day of culture, feed and glucose were added to bring the culture concentration to 8 g / L. On the sixth day of culture, the cell culture medium was collected.

[0332] Translational-level analysis was performed on a series of antibodies. Cell culture media were purified using a Protein A chromatography column, and absorption peaks were collected for mass spectrometry analysis. Mass spectrometry analysis revealed that the molecular weight of the chimeric antibodies (scFv-Fc) was approximately 100 kDa, consistent with the theoretical molecular weight, indicating a dimer form. Simultaneously, the collected samples were analyzed by 10% SDS-PAGE electrophoresis after reduction and non-reduction. The reduced SDS-PAGE electrophoresis pattern showed a molecular weight of approximately 50 kDa, while the non-reduced SDS-PAGE electrophoresis pattern showed a single band of approximately 100 kDa, consistent with theoretical band sizes. The purified samples were dialyzed overnight at 4°C using 0.02 M PBS buffer (pH 7.4).

[0333] Example 3: Using multiple cell lines, FACS was used to identify the specificity and species cross-species of antibodies.

[0334] The obtained antibody (prepared in Example 2) was reacted with human CCR8-overexpressing cell lines CHO-CCR8, mouse CCR8-293T-CCR8-M, and monkey CCR8-293T-CCR8-Cyn to analyze whether the antibody could bind to CCR8 antigens of different species. Simultaneously, the human CCR4-overexpressing cell line 293-CCR4, as well as CHO and 293T cell lines, were reacted to analyze whether the obtained antibody specifically binds to CCR8 and whether it exhibits any non-specific binding with other cell lines that do not express CCR8. In this example, cells overexpressing human CCR8 were digested with trypsin, counted, and resuspended to a cell density of 1E7 / ml. 100 μl / well of cell suspension was added to a U-bottom 96-well plate, centrifuged at 300g for 5 minutes, and the supernatant was discarded. The obtained anti-CCR8 antibody was used as the primary antibody, and Shionogi antibody 10A11 (total antibody) was used as a positive control at a concentration of 10 μg / mL. Cells were resuspended in the diluted primary antibody at a concentration of 100 μl / well and incubated at 4°C for 1 hour. Cells were washed twice with PBS, centrifuged at 300g for 5 minutes, and the supernatant was discarded. Cells were resuspended in 100 μl / well of secondary antibody diluted 1:500 with FACS buffer, and incubated at 4°C for 40 minutes. Cells were washed twice with PBS, centrifuged at 300g for 5 minutes, and the supernatant was discarded. Cells were resuspended in 200 μl / well of DPBS and analyzed using a FACS analyzer.

[0335] The results are as follows Figure 2 As shown, the peak of 1H4 shifted significantly to the right compared to the NC control, indicating that 1H4 strongly binds to the overexpressing cell line CHO-hCCR8, while 1G3, 2G12, 5D6, 5G6, and 8H7 showed weak binding. Species crossover results are shown below. Figure 3 and Figure 4 As shown, 5D6, 5G6, and 8H7 bind to the mouse CCR8 overexpressing cell line 293T-mCCR8 to some extent, while 1G3, 1H4, and 2G12 do not bind to the 293T-mCCR8 cell line. Furthermore, 1H4, 5D6, 5G6, and 8H7 can bind to the monkey CCR8 overexpressing cell line 293-cynCCR8, while 1G3 and 2G12 do not bind. Specific binding results are as follows... Figure 5 , Figure 6 and Figure 7 As shown, 1H4, 1G3, and 2G12 do not bind to the 293T-hCCR4, CHO, and 293T cell lines, while 5D6, 5G6, and 8H7 bind to the 293T-hCCR4 and 293T cell lines to some extent. Furthermore, the positive antibody binds weakly to the 293T-hCCR4 and 293T cell lines. In summary, 1H4 has better specificity than the positive antibody. The positive control 10A11 contains the heavy chain shown in SEQ ID NO: 112 and the light chain shown in SEQ ID NO: 113.

[0336] EVQLVESGGALVKPGGSLRLSCAASGFTFSTYALYWVRQAPGKGLEWVGRIRSKSNNYATYYADSVKDRFTISRDDSKNTLYLQMNSLKTEDTAVYYCTRARFYYSDYGYAMDYWGQGTLVTVSSASTKGPSVFPLAPSSKSTSGGTAALGCLVKDYFPEPVTVSWNSGALTSGVHTFPAVLQSSGLYSLSSVVTVPSSSLGTQTYICNVNHKPSNTKVDKKVEPKSCDKTHTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSREEMTKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHEALHNHYTQKSLSLSPGK (SEQ ID NO: 112).

[0337] DIVMTQSPDSLAVSLGERATINCRSSKSLLHSNGNTYLYWYQQKPGQPPKLLIYRMSNLASGVPDRFSGSGSGTDFTLTISSLQAEDVAVYYCMQHLEYPLTFGQGTKLEIKRTVAAPSVFIFPPSDEQLKSGTASVVCLLNNFYPREAKVQWKVDNALQSGNSQESVTEQDSKDSTYSLSSTLTLSKADYEKHKVYACEVTHQGLSSPVTKSFNRGEC (SEQ ID NO: 113).

[0338] Example 4 Binding ability of anti-CCR8 antibody 1H4 to the high-expression cell line CHO-CCR8

[0339] This embodiment uses the FACS binding method to analyze the half-maximal effective concentration (EC50) of antibody molecules, providing important information for the research and development process. In this embodiment, the anti-CCR8 antibody prepared in Example 2 was started at 100 μg / mL and successively diluted 10-fold, for a total of 8 concentrations. The binding ability of antibody 1H4-(scFv-Fc) to the highly expressed cell line CHO-CCR8 was detected. The procedure was the same as in Example 3. Affinity refers to the strength of the binding between a single molecule and its ligand. It can usually be assessed by detecting the binding ability with positive cell lines using FACS to evaluate the strength of the interaction between two molecules and rank them. The smaller the EC50 value, the greater the affinity of the antibody for its target. Figure 8 As shown, the obtained CCR8 antibody 1H4-(scFv-Fc) has an EC50 greater than 10 nM binding ability with the overexpressed cell line CHO-CCR8.

[0340] Example 5: Affinity maturation of anti-CCR8 antibody

[0341] In this embodiment, antibody 1H4 underwent affinity maturation to improve its binding ability to the target. Using NNK degenerate primers, four mutant saturated libraries for the first round of affinity maturation were constructed: H1H2 (VH-CDR1+VH-CDR2), H3 (VH-CDR3), L1L2 (VL-CDR1+VL-CDR2), and L3 (VL-CDR3). Subsequently, using phage libraries screened three times from these four libraries as templates, second-round affinity maturation libraries H1H2H3, H1H2L1L2, H1H2L3, H3L1L2, H3L3, and L1L2L3 were constructed. This process was repeated for two to three rounds of affinity maturation. Preliminary screening was performed using ELISA and FACS. The affinity-matured sequences were then constructed into mammalian expression vectors for protein expression and purification. The purified mutants were then identified using FACS. The results are as follows: Figure 9 As shown in Table 4, the mutant after affinity maturation exhibits stronger binding activity with the parent line and the overexpressing cell line CHO-hCCR8 than the parent line, and its binding activity is comparable to that of positive 10A11.

[0342] Table 4. Binding ability of the 1H4 affinity-mature mutant total antibody to CHO-hCCR8

[0343]

[0344] Example 6: The mutant possesses ADCC reporter gene bioactivity.

[0345] Collect CHO-hCCR8 cells overexpressing human CCR8 and adjust the cell density to 4*102. 512.5 μL / well was added to white ViewPlate 96-well plates. The test antibody (prepared in Example 5) was diluted with 1640 medium. The positive antibody was 10A11, with an initial concentration of 100 μg / mL, serially diluted 5-fold to a total of 7 concentrations. 25 μL / well of the diluted antibody was added to each well of a white ViewPlate 96-well plate and incubated at 37°C and 5% CO2 for 1 h. Jurkat-NFAT-Luc2 / CD16 cells were collected and the cell density was adjusted to 4*10⁻⁶ cells / well. 5 Cells / mL were added to white ViewPlate 96-well plates at a concentration of 12.5 μL / well. The plates were incubated overnight at 37°C for 6 hours. Then, 30 μL / well of Luciferase substrate was added, and RLU was read using a microplate reader. Data were analyzed using GraphPadPrism. Results are as follows: Figure 10 As shown, the affinity-mature mutant 1H4-1-H4 has a strong ADCC effect, with an EC50 of 0.08 nM, which is comparable to the effect of the positive antibody 10A11.

[0346] In the description of this specification, the references to terms such as "some embodiments," "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0347] Although specific embodiments of the invention have been described in detail, those skilled in the art will understand that various modifications and variations can be made to the details based on all the published teachings, and all such changes are within the scope of protection of the invention. The entire scope of the invention is given by the appended claims and any equivalents thereof.

Claims

1. A fully human antibody or antigen-binding fragment that specifically binds to human CCR8, characterized in that, The antibody or antigen-binding fragment comprises a heavy chain variable region and a light chain variable region, wherein the heavy chain variable region comprises complementarity-determining regions: H-CDR1, H-CDR2, and H-CDR3, and the light chain variable region comprises complementarity-determining regions: L-CDR1, L-CDR2, and L-CDR3, wherein a combination selected from the group consisting of: (1) The H-CDR1, H-CDR2, and H-CDR3 are the amino acid sequences shown in SEQ ID NO: 37, SEQ ID NO: 38, and SEQ ID NO: 39, respectively; and the L-CDR1, L-CDR2, and L-CDR3 are the amino acid sequences shown in SEQ ID NO: 34, SEQ ID NO: 35, and SEQ ID NO: 36, respectively; or (2) The H-CDR1, H-CDR2, and H-CDR3 are the amino acid sequences shown in SEQ ID NO: 40, SEQ ID NO: 41, and SEQ ID NO: 33, respectively; and the L-CDR1, L-CDR2, and L-CDR3 are the amino acid sequences shown in SEQ ID NO: 42, SEQ ID NO: 35, and SEQ ID NO: 36, respectively; or (3) The H-CDR1, H-CDR2, and H-CDR3 are the amino acid sequences shown in SEQ ID NO: 43, SEQ ID NO: 44, and SEQ ID NO: 45, respectively; and the L-CDR1, L-CDR2, and L-CDR3 are the amino acid sequences shown in SEQ ID NO: 46, SEQ ID NO: 47, and SEQ ID NO: 48, respectively; or (4) The H-CDR1, H-CDR2, and H-CDR3 are the amino acid sequences shown in SEQ ID NO: 49, SEQ ID NO: 50, and SEQ ID NO: 33, respectively; and the L-CDR1, L-CDR2, and L-CDR3 are the amino acid sequences shown in SEQ ID NO: 34, SEQ ID NO: 35, and SEQ ID NO: 36, respectively; or (5) The H-CDR1, H-CDR2, and H-CDR3 are the amino acid sequences shown in SEQ ID NO: 31, SEQ ID NO: 32, and SEQ ID NO: 51, respectively; and the L-CDR1, L-CDR2, and L-CDR3 are the amino acid sequences shown in SEQ ID NO: 52, SEQ ID NO: 35, and SEQ ID NO: 36, respectively; or (6) The H-CDR1, H-CDR2, and H-CDR3 are the amino acid sequences shown in SEQ ID NO: 53, SEQ ID NO: 54, and SEQ ID NO: 55, respectively; and the L-CDR1, L-CDR2, and L-CDR3 are the amino acid sequences shown in SEQ ID NO: 56, SEQ ID NO: 57, and SEQ ID NO: 58, respectively; or (7) The H-CDR1, H-CDR2 and H-CDR3 are the amino acid sequences shown in SEQ ID NO: 31, SEQ ID NO: 32 and SEQ ID NO: 33, respectively; and the L-CDR1, L-CDR2 and L-CDR3 are the amino acid sequences shown in SEQ ID NO: 34, SEQ ID NO: 35 and SEQ ID NO: 36, respectively.

2. The antibody or antigen-binding fragment according to claim 1, characterized in that, The antibody or antigen-binding fragment comprises at least one of a heavy chain variable region and a light chain variable region, and at least a portion of at least one of the heavy chain variable region and the light chain variable region is derived from at least one of a human antibody or a mutant thereof.

3. The antibody or antigen-binding fragment according to claim 1 or 2, characterized in that, The heavy chain variable region of the antibody or antigen-binding fragment is an amino acid sequence that has at least 90% identity with any one of SEQ ID NO: 64-70.

4. The antibody or antigen-binding fragment according to claim 1 or 2, characterized in that, The light chain variable region of the antibody or antigen-binding fragment is an amino acid sequence that has at least 90% identity with any one of SEQ ID NO: 77-82.

5. The antibody or antigen-binding fragment according to claim 1 or 2, characterized in that, The antibody or antigen-binding fragment comprises a heavy chain and a light chain, wherein the heavy chain and light chain are selected from a combination of the following groups: (1) The heavy chain has the amino acid sequence shown in SEQ ID NO: 94, and the light chain has the amino acid sequence shown in SEQ ID NO: 101; or (2) The heavy chain has the amino acid sequence shown in SEQ ID NO: 95, and the light chain has the amino acid sequence shown in SEQ ID NO: 102; or (3) The heavy chain has the amino acid sequence shown in SEQ ID NO: 96, and the light chain has the amino acid sequence shown in SEQ ID NO: 103; or (4) The heavy chain has the amino acid sequence shown in SEQ ID NO: 97, and the light chain has the amino acid sequence shown in SEQ ID NO: 104; or (5) The heavy chain has the amino acid sequence shown in SEQ ID NO: 98, and the light chain has the amino acid sequence shown in SEQ ID NO: 105; or (6) The heavy chain has the amino acid sequence shown in SEQ ID NO: 99, and the light chain has the amino acid sequence shown in SEQ ID NO: 106; or (7) The heavy chain is the amino acid sequence shown in SEQ ID NO: 100, and the light chain is the amino acid sequence shown in SEQ ID NO:

107.

6. The antibody or antigen-binding fragment according to claim 1 or 2, characterized in that, The antibody or antigen-binding fragment comprises at least one of a heavy chain constant region and a light chain constant region, and at least a portion of at least one of the heavy chain constant region and the light chain constant region comes from at least one of a human antibody or a mutant thereof.

7. An isolated nucleic acid molecule, characterized in that, The nucleic acid molecule comprises a nucleotide sequence encoding an antibody or antigen-binding fragment as described in any one of claims 1-6.

8. An expression carrier, characterized in that, The expression vector carries the nucleic acid molecule as described in claim 7.

9. A host cell, characterized in that, The host cell comprises the nucleic acid molecule of claim 7 or the expression vector of claim 8.

10. A pharmaceutical composition, characterized in that, The pharmaceutical composition comprises the antibody or antigen-binding fragment of any one of claims 1-6, the nucleic acid molecule of claim 7, the expression vector of claim 8, the host cell of claim 9, and a pharmaceutically acceptable vector.

11. Use of the antibody or antigen-binding fragment of any one of claims 1-6, the nucleic acid molecule of claim 7, the expression vector of claim 8, the host cell of claim 9, or the pharmaceutical composition of claim 10 in the preparation of a medicament, wherein the medicament is used to prevent, alleviate, and / or treat CCR8-related diseases; wherein the CCR8-related disease is a tumor, and the tumor is selected from breast cancer, kidney cancer, bladder cancer, colon cancer, metastatic brain cancer, and metastatic liver cancer.

12. A reagent kit, characterized in that, The kit contains the antibody or antigen-binding fragment as described in any one of claims 1-6, and instructions for use.

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