Anti-CD79b antibody and its use

Abstract

The present disclosure relates to anti-CD79b (cluster of differentiation 79B) antibodies, antigen-binding fragments thereof, antibody-drug conjugates (ADCs) derived therefrom, and uses thereof.

Description

[Technical Field]

[0001] This disclosure relates to an anti-CD79b (differentiation antigen group 79B) antibody, its antigen-binding fragment, an antibody-drug conjugate (ADC) derived therefrom, and its use. [Background technology]

[0002] CD79 is a signaling component of the B cell receptor and functions as a covalent heterodimer containing CD79a and CD79b. CD79b contains an extracellular immunoglobulin (Ig) domain, a transmembrane domain, an intracellular signaling domain, and an immunoreceptor tyrosine-based activation motif (ITAM) domain. CD79b expression has been detected on the surface of almost all non-Hodgkin lymphomas (NHL), acute lymphoblastic leukemia (ALL), and chronic lymphocytic leukemia (CLL).

[0003] CD79b is an intriguing therapeutic target for B-cell malignancies for several reasons. Firstly, this receptor is not only widely expressed in B-cell malignancies, but its expression remains unchanged even after loss of CD19 or CD20, making it a prominent alternative to targeted therapies for CD19 or CD20. Secondly, when the B-cell receptor is cross-linked, it is targeted to the major histocompatibility complex class II compartment, a lysosomal-like compartment, as part of B-cell class II antigen presentation.

[0004] Given the important role of CD79b in cancer, there is a need to develop therapeutic drugs that target CD79b. [Overview of the Initiative]

[0005] This disclosure relates to an anti-CD79b antibody, its antigen-binding fragment, and its use.

[0006] In one embodiment, the present disclosure relates to an antibody or antigen-binding fragment thereof that binds to CD79b (differentiation antigen group 79B), A heavy chain variable region (VH) comprising complementarity-determining regions (CDRs) 1, 2, and 3, wherein the VH CDR1 region includes an amino acid sequence that is at least 80% identical to the selected VH CDR1 amino acid sequence, the VH CDR2 region includes an amino acid sequence that is at least 80% identical to the selected VH CDR2 amino acid sequence, and the VH CDR3 region includes an amino acid sequence that is at least 80% identical to the selected VH CDR3 amino acid sequence. A light chain variable region (VL) comprising CDR1, 2, and 3, wherein the VL CDR1 region comprises an amino acid sequence that is at least 80% identical to the selected VL CDR1 amino acid sequence, the VL CDR2 region comprises an amino acid sequence that is at least 80% identical to the selected VL CDR2 amino acid sequence, and the VL CDR3 region comprises an amino acid sequence that is at least 80% identical to the selected VL CDR3 amino acid sequence. The selected VH CDR1, 2, and 3 amino acid sequences and the selected VL CDR1, 2, and 3 amino acid sequences are, (1) The selected VH CDR1, 2, and 3 amino acid sequences are shown in SEQ ID NOs. 9, 11, and 13, respectively, and the selected VL CDR1, 2, and 3 amino acid sequences are shown in SEQ ID NOs. 14 to 16, respectively. (2) The selected VH CDR1, 2, and 3 amino acid sequences are shown in SEQ ID NOs. 19, 21, and 23, respectively, and the selected VL CDR1, 2, and 3 amino acid sequences are shown in SEQ ID NOs. 24 to 26, respectively. (3) The selected VH CDR1, 2, and 3 amino acid sequences are shown in SEQ ID NOs. 29, 31, and 33, respectively, and the selected VL CDR1, 2, and 3 amino acid sequences are shown in SEQ ID NOs. 34 to 36, respectively. (4) The selected VH CDR1, 2, and 3 amino acid sequences are shown in SEQ ID NOs. 39, 41, and 43, respectively, and the selected VL CDR1, 2, and 3 amino acid sequences are shown in SEQ ID NOs. 44 to 46, respectively. (5) The selected VH CDR1, 2, and 3 amino acid sequences are shown in SEQ ID NOs. 49, 51, and 53, respectively, and the selected VL CDR1, 2, and 3 amino acid sequences are shown in SEQ ID NOs. 54 to 56, respectively. (6) The selected VH CDR1, 2, and 3 amino acid sequences are shown in SEQ ID NOs. 59, 61, and 63, respectively, and the selected VL CDR1, 2, and 3 amino acid sequences are shown in SEQ ID NOs. 64 to 66, respectively. (7) The selected VH CDR1, 2, and 3 amino acid sequences are shown in SEQ ID NOs. 10, 12, and 13, respectively, and the selected VL CDR1, 2, and 3 amino acid sequences are shown in SEQ ID NOs. 14 to 16, respectively. (8) The selected VH CDR1, 2, and 3 amino acid sequences are shown in SEQ ID NOs. 20, 22, and 23, respectively, and the selected VL CDR1, 2, and 3 amino acid sequences are shown in SEQ ID NOs. 24 to 26, respectively. (9) The selected VH CDR1, 2, and 3 amino acid sequences are shown in SEQ ID NOs. 30, 32, and 33, respectively, and the selected VL CDR1, 2, and 3 amino acid sequences are shown in SEQ ID NOs. 34 to 36, respectively. (10) The selected VH CDR1, 2, and 3 amino acid sequences are shown in SEQ ID NOs. 40, 42, and 43, respectively, and the selected VL CDR1, 2, and 3 amino acid sequences are shown in SEQ ID NOs. 44 to 46, respectively. (11) The selected VH CDR1, 2, and 3 amino acid sequences are shown in SEQ ID NOs. 50, 52, and 53, respectively, and the selected VL CDR1, 2, and 3 amino acid sequences are shown in SEQ ID NOs. 54 to 56, respectively, and (12) The present invention relates to an antibody or an antigen-binding fragment thereof, which is one of those in which the selected VH CDR1, 2, and 3 amino acid sequences are shown in SEQ ID NOs. 60, 62, and 63, respectively, and the selected VL CDR1, 2, and 3 amino acid sequences are shown in SEQ ID NOs. 64 to 66, respectively.

[0007] In some embodiments, according to the Kabat definition, said VH comprises CDR1, 2 and 3 having the amino acid sequences set forth in SEQ ID NO: 9, 11 and 13, respectively, and said VL comprises CDR1, 2 and 3 having the amino acid sequences set forth in SEQ ID NO: 14 to 16, respectively.

[0008] In some embodiments, according to the Kabat definition, said VH comprises CDR1, 2 and 3 having the amino acid sequences set forth in SEQ ID NO: 19, 21 and 23, respectively, and said VL comprises CDR1, 2 and 3 having the amino acid sequences set forth in SEQ ID NO: 24 to 26, respectively.

[0009] In some embodiments, according to the Kabat definition, said VH comprises CDR1, 2 and 3 having the amino acid sequences set forth in SEQ ID NO: 29, 31 and 33, respectively, and said VL comprises CDR1, 2 and 3 having the amino acid sequences set forth in SEQ ID NO: 34 to 36, respectively.

[0010] In some embodiments, according to the Kabat definition, said VH comprises CDR1, 2 and 3 having the amino acid sequences set forth in SEQ ID NO: 39, 41 and 43, respectively, and said VL comprises CDR1, 2 and 3 having the amino acid sequences set forth in SEQ ID NO: 44 to 46, respectively.

[0011] In some embodiments, according to the Kabat definition, said VH comprises CDR1, 2 and 3 having the amino acid sequences set forth in SEQ ID NO: 49, 51 and 53, respectively, and said VL comprises CDR1, 2 and 3 having the amino acid sequences set forth in SEQ ID NO: 54 to 56, respectively.

[0012] In some embodiments, according to the Kabat definition, said VH comprises CDR1, 2 and 3 having the amino acid sequences set forth in SEQ ID NO: 59, 61 and 63, respectively, and said VL comprises CDR1, 2 and 3 having the amino acid sequences set forth in SEQ ID NO: 64 to 66, respectively.

[0013] In some embodiments, according to the Kotia definition, the VH comprises CDR1, 2, and 3 having the amino acid sequences shown in SEQ ID NOs: 10, 12, and 13, respectively, and the VL comprises CDR1, 2, and 3 having the amino acid sequences shown in SEQ ID NOs: 14 to 16, respectively.

[0014] In some embodiments, according to the Kotia definition, the VH comprises CDR1, 2, and 3 having the amino acid sequences shown in SEQ ID NOs. 20, 22, and 23, respectively, and the VL comprises CDR1, 2, and 3 having the amino acid sequences shown in SEQ ID NOs. 24 to 26, respectively.

[0015] In some embodiments, according to the Kotia definition, the VH comprises CDR1, 2, and 3 having the amino acid sequences shown in SEQ ID NOs. 30, 32, and 33, respectively, and the VL comprises CDR1, 2, and 3 having the amino acid sequences shown in SEQ ID NOs. 34 to 36, respectively.

[0016] In some embodiments, according to the Kotia definition, the VH comprises CDR1, 2, and 3 having the amino acid sequences shown in SEQ ID NOs. 40, 42, and 43, respectively, and the VL comprises CDR1, 2, and 3 having the amino acid sequences shown in SEQ ID NOs. 44 to 46, respectively.

[0017] In some embodiments, according to the Kotia definition, the VH comprises CDR1, 2, and 3 having the amino acid sequences shown in SEQ ID NOs. 50, 52, and 53, respectively, and the VL comprises CDR1, 2, and 3 having the amino acid sequences shown in SEQ ID NOs. 54 to 56, respectively.

[0018] In some embodiments, according to the Kotia definition, the VH comprises CDR1, 2, and 3 having the amino acid sequences shown in SEQ ID NOs. 60, 62, and 63, respectively, and the VL comprises CDR1, 2, and 3 having the amino acid sequences shown in SEQ ID NOs. 64 to 66, respectively.

[0019] In some embodiments, the antibody or its antigen-binding fragment specifically binds to human, mouse, monkey, or canine CD79b.

[0020] In some embodiments, the antibody or its antigen-binding fragment is a humanized antibody or its antigen-binding fragment, a single-chain variable fragment (scFv), a one-arm antibody, and / or a multispecific antibody (e.g., a bispecific antibody).

[0021] In some embodiments, the antibody or its antigen-binding fragment includes a human IgG1 constant region, a human IgG2 constant region, or a human IgG4 constant region.

[0022] In one aspect, the present disclosure relates to a nucleic acid comprising a polynucleotide encoding a polypeptide, wherein the polypeptide is (1) An immunoglobulin heavy chain or fragment thereof containing VH, which includes complementarity-determining regions (CDRs) 1, 2, and 3, respectively, which include the amino acid sequences shown in SEQ ID NOs. 9, 11, and 13, respectively, wherein when the VH is paired with a light chain variable region (VL) containing the amino acid sequence shown in SEQ ID NO. 8, the immunoglobulin heavy chain or fragment thereof binds to CD79b. (2) An immunoglobulin light chain or fragment thereof comprising a VL containing complementarity-determining regions (CDRs) 1, 2, and 3, respectively, which contain the amino acid sequences shown in SEQ ID NOs. 14 to 16, wherein when the VL is paired with a VH containing the amino acid sequence shown in SEQ ID NO. 7, the immunoglobulin light chain or fragment thereof binds to CD79b. (3) An immunoglobulin heavy chain or fragment thereof comprising VH comprising complementarity-determining regions (CDRs) 1, 2, and 3, respectively, which include the amino acid sequences shown in SEQ ID NOs. 19, 21, and 23, wherein when the VH is paired with a light chain variable region (VL) containing the amino acid sequence shown in SEQ ID NO. 18, the immunoglobulin heavy chain or fragment thereof binds to CD79b. (4) An immunoglobulin light chain or fragment thereof comprising a VL containing complementarity-determining regions (CDRs) 1, 2, and 3, respectively, which each contain the amino acid sequences shown in SEQ ID NOs. 24 to 26, wherein when the VL is paired with a VH containing the amino acid sequence shown in SEQ ID NO. 17, the immunoglobulin light chain or fragment thereof binds to CD79b. (5) An immunoglobulin heavy chain or fragment thereof comprising VH comprising complementarity-determining regions (CDRs) 1, 2, and 3, respectively, which include the amino acid sequences shown in SEQ ID NOs. 29, 31, and 33, wherein when VH is paired with a light chain variable region (VL) comprising the amino acid sequence shown in SEQ ID NO. 28, the immunoglobulin heavy chain or fragment thereof binds to CD79b. (6) An immunoglobulin light chain or fragment thereof comprising a VL containing CDR1, 2, and 3, respectively, which each contain the amino acid sequences shown in SEQ ID NOs. 34 to 36, wherein when the VL is paired with a VH containing the amino acid sequence shown in SEQ ID NO. 27, the immunoglobulin light chain or fragment thereof binds to CD79b. (7) An immunoglobulin heavy chain or fragment thereof comprising VH comprising complementarity-determining regions (CDRs) 1, 2, and 3, respectively, which include the amino acid sequences shown in SEQ ID NOs. 39, 41, and 43, wherein when VH is paired with a light chain variable region (VL) comprising the amino acid sequence shown in SEQ ID NO. 38, the immunoglobulin heavy chain or fragment thereof binds to CD79b. (8) An immunoglobulin light chain or fragment thereof comprising a VL containing CDR1, 2, and 3, respectively, which each contain the amino acid sequences shown in SEQ ID NOs. 44 to 46, wherein when the VL is paired with a VH containing the amino acid sequence shown in SEQ ID NO. 37, the immunoglobulin light chain or fragment thereof binds to CD79b. (9) An immunoglobulin heavy chain or fragment thereof comprising VH comprising complementarity-determining regions (CDRs) 1, 2, and 3, respectively, comprising the amino acid sequences shown in SEQ ID NOs. 49, 51, and 53, wherein when the VH is paired with a light chain variable region (VL) comprising the amino acid sequence shown in SEQ ID NO. 48, the immunoglobulin heavy chain or fragment thereof binds to CD79b. (10) An immunoglobulin light chain or fragment thereof comprising a VL containing CDR1, 2, and 3, each containing the amino acid sequences shown in SEQ ID NOs. 54 to 56, wherein when the VL is paired with a VH containing the amino acid sequence shown in SEQ ID NO. 47, the immunoglobulin light chain or fragment thereof binds to CD79b. (11) An immunoglobulin heavy chain or fragment thereof comprising VH comprising complementarity-determining regions (CDRs) 1, 2, and 3, respectively, comprising the amino acid sequences shown in SEQ ID NOs. 59, 61, and 63, wherein when the VH is paired with a light chain variable region (VL) comprising the amino acid sequence shown in SEQ ID NO. 58, the immunoglobulin heavy chain or fragment thereof binds to CD79b. (12) An immunoglobulin light chain or fragment thereof comprising a VL containing CDR1, 2, and 3, each containing the amino acid sequences shown in SEQ ID NOs. 64 to 66, wherein when the VL is paired with a VH containing the amino acid sequence shown in SEQ ID NO. 57, the immunoglobulin light chain or fragment thereof binds to CD79b. (13) An immunoglobulin heavy chain or fragment thereof comprising VH comprising complementarity-determining regions (CDRs) 1, 2, and 3, respectively, which include the amino acid sequences shown in SEQ ID NOs. 10, 12, and 13, wherein when VH is paired with a light chain variable region (VL) comprising the amino acid sequence shown in SEQ ID NO. 8, the immunoglobulin heavy chain or fragment thereof binds to CD79b. (14) An immunoglobulin heavy chain or fragment thereof comprising VH comprising complementarity-determining regions (CDRs) 1, 2, and 3, respectively, which include the amino acid sequences shown in SEQ ID NOs. 20, 22, and 23, wherein when the VH is paired with a light chain variable region (VL) comprising the amino acid sequence shown in SEQ ID NO. 18, the immunoglobulin heavy chain or fragment thereof binds to CD79b. (15) An immunoglobulin heavy chain or fragment thereof comprising VH comprising complementarity-determining regions (CDRs) 1, 2, and 3, respectively, which include the amino acid sequences shown in SEQ ID NOs. 30, 32, and 33, wherein when the VH is paired with a light chain variable region (VL) comprising the amino acid sequence shown in SEQ ID NO. 28, the immunoglobulin heavy chain or fragment thereof binds to CD79b. (16) An immunoglobulin heavy chain or fragment thereof comprising VH comprising complementarity-determining regions (CDRs) 1, 2, and 3, respectively, comprising the amino acid sequences shown in SEQ ID NOs. 40, 42, and 43, wherein when the VH is paired with a light chain variable region (VL) comprising the amino acid sequence shown in SEQ ID NO. 38, the immunoglobulin heavy chain or fragment thereof binds to CD79b. (17) An immunoglobulin heavy chain or fragment thereof comprising VH comprising complementarity-determining regions (CDRs) 1, 2, and 3, respectively, which include the amino acid sequences shown in SEQ ID NOs. 50, 52, and 53, wherein when the VH is paired with a light chain variable region (VL) comprising the amino acid sequence shown in SEQ ID NO. 48, the immunoglobulin heavy chain or fragment thereof binds to CD79b. (18) An immunoglobulin heavy chain or fragment thereof comprising VH comprising complementarity-determining regions (CDRs) 1, 2, and 3, respectively, comprising the amino acid sequences shown in SEQ ID NOs. 60, 62, and 63, wherein when the VH is paired with a light chain variable region (VL) comprising the amino acid sequence shown in SEQ ID NO. 58, the immunoglobulin heavy chain or fragment thereof binds to CD79b. (19) An immunoglobulin heavy chain or fragment thereof comprising VH comprising complementarity-determining regions (CDRs) 1, 2, and 3, respectively, which include the amino acid sequences shown in SEQ ID NOs. 19, 21, and 23, wherein when VH is paired with a light chain variable region (VL) comprising the amino acid sequence shown in SEQ ID NO. 70, the immunoglobulin heavy chain or fragment thereof binds to CD79b. (20) An immunoglobulin light chain or fragment thereof comprising a VL containing complementarity-determining regions (CDRs) 1, 2, and 3, respectively, which each contain the amino acid sequences shown in SEQ ID NOs. 24 to 26, wherein when the VL is paired with a VH containing the amino acid sequence shown in SEQ ID NO. 69, the immunoglobulin light chain or fragment thereof binds to CD79b. (21) An immunoglobulin heavy chain or fragment thereof comprising VH comprising complementarity-determining regions (CDRs) 1, 2, and 3, respectively, which include the amino acid sequences shown in SEQ ID NOs. 20, 22, and 23, wherein when VH is paired with a light chain variable region (VL) comprising the amino acid sequence shown in SEQ ID NO. 70, the immunoglobulin heavy chain or fragment thereof binds to CD79b. (22) An immunoglobulin heavy chain or fragment thereof comprising VH comprising complementarity-determining regions (CDRs) 1, 2, and 3, respectively, comprising the amino acid sequences shown in SEQ ID NOs. 39, 41, and 43, wherein when the VH is paired with a light chain variable region (VL) comprising the amino acid sequence shown in SEQ ID NO. 72, the immunoglobulin heavy chain or fragment thereof binds to CD79b. (23) An immunoglobulin light chain or fragment thereof comprising a VL containing CDR1, 2, and 3, respectively, which each contain the amino acid sequences shown in SEQ ID NOs. 44 to 46, wherein when the VL is paired with a VH containing the amino acid sequence shown in SEQ ID NO. 71, the immunoglobulin light chain or fragment thereof binds to CD79b. (24) An immunoglobulin heavy chain or fragment thereof comprising VH comprising complementarity-determining regions (CDRs) 1, 2, and 3, respectively, comprising the amino acid sequences shown in SEQ ID NOs. 40, 42, and 43, wherein when the VH is paired with a light chain variable region (VL) comprising the amino acid sequence shown in SEQ ID NO. 72, the immunoglobulin heavy chain or fragment thereof binds to CD79b. (25) An immunoglobulin heavy chain or fragment thereof comprising VH comprising complementarity-determining regions (CDRs) 1, 2, and 3, respectively, which include the amino acid sequences shown in SEQ ID NOs. 49, 51, and 53, wherein when the VH is paired with a light chain variable region (VL) comprising the amino acid sequence shown in SEQ ID NO. 73, the immunoglobulin heavy chain or fragment thereof binds to CD79b. (26) An immunoglobulin light chain or fragment thereof comprising a VL comprising CDR1, 2, and 3, respectively, which each comprises the amino acid sequences shown in SEQ ID NOs. 54 to 56, wherein when the VL is paired with a VH comprising the amino acid sequence shown in SEQ ID NO. 74, the immunoglobulin light chain or fragment thereof binds to CD79b. (27) An immunoglobulin heavy chain or fragment thereof comprising VH comprising complementarity-determining regions (CDRs) 1, 2, and 3, respectively, comprising the amino acid sequences shown in SEQ ID NOs. 50, 52, and 53, wherein when the VH is paired with a light chain variable region (VL) comprising the amino acid sequence shown in SEQ ID NO. 73, the immunoglobulin heavy chain or fragment thereof binds to CD79b. (28) An immunoglobulin heavy chain or fragment thereof comprising VH comprising complementarity-determining regions (CDRs) 1, 2, and 3, respectively, which include the amino acid sequences shown in SEQ ID NOs. 59, 61, and 63, wherein when the VH is paired with a light chain variable region (VL) comprising the amino acid sequence shown in SEQ ID NO. 76, the immunoglobulin heavy chain or fragment thereof binds to CD79b. (29) An immunoglobulin light chain or fragment thereof comprising a VL containing CDR1, 2, and 3, each containing the amino acid sequences shown in SEQ ID NOs. 64 to 66, wherein when the VL is paired with a VH containing the amino acid sequence shown in SEQ ID NO. 75, the immunoglobulin light chain or fragment thereof binds to CD79b. (30) The present invention relates to a nucleic acid comprising an immunoglobulin heavy chain or fragment thereof, which includes a VH comprising complementarity-determining regions (CDRs) 1, 2, and 3, respectively, which include the amino acid sequences shown in SEQ ID NOs. 60, 62, and 63, and wherein the VH, when paired with a light chain variable region (VL) containing the amino acid sequence shown in SEQ ID NO. 76, binds to CD79b.

[0023] In some embodiments, the nucleic acid comprises a polynucleotide encoding a polypeptide comprising an immunoglobulin light chain or fragment thereof, comprising a VL containing CDR1, 2, and 3, each having the amino acid sequences shown in SEQ ID NOs. 14-16.

[0024] In some embodiments, the nucleic acid comprises a polynucleotide encoding a polypeptide containing an immunoglobulin light chain or fragment thereof, which includes a VL containing CDR1, 2, and 3, each containing the amino acid sequences shown in SEQ ID NOs. 24-26.

[0025] In some embodiments, the nucleic acid comprises a polynucleotide encoding a polypeptide comprising an immunoglobulin light chain or fragment thereof, comprising a VL containing CDR1, 2, and 3, each having the amino acid sequences shown in SEQ ID NOs. 34-36.

[0026] In some embodiments, the nucleic acid comprises a polynucleotide encoding a polypeptide comprising an immunoglobulin light chain or fragment thereof, comprising a VL containing CDR1, 2, and 3, each having the amino acid sequences shown in SEQ ID NOs. 44-46.

[0027] In some embodiments, the nucleic acid comprises a polynucleotide encoding a polypeptide comprising an immunoglobulin light chain or fragment thereof, comprising a VL containing CDR1, 2, and 3, each having the amino acid sequences shown in SEQ ID NOs. 54-56.

[0028] In some embodiments, the nucleic acid comprises a polynucleotide encoding a polypeptide containing an immunoglobulin light chain or fragment thereof, which includes a VL containing CDR1, 2, and 3, each containing the amino acid sequences shown in SEQ ID NOs. 64-66.

[0029] In some embodiments, the nucleic acid comprises a polynucleotide encoding a polypeptide comprising an immunoglobulin heavy chain or fragment thereof, comprising VH containing CDR1, 2, and 3, each having the amino acid sequences shown in SEQ ID NOs: 9, 11, and 13, respectively.

[0030] In some embodiments, the nucleic acid comprises a polynucleotide encoding a polypeptide comprising an immunoglobulin heavy chain or fragment thereof, comprising VH containing CDR1, 2, and 3, each having the amino acid sequences shown in SEQ ID NOs. 19, 21, and 23, respectively.

[0031] In some embodiments, the nucleic acid comprises a polynucleotide encoding a polypeptide comprising an immunoglobulin heavy chain or fragment thereof, comprising VH containing CDR1, 2, and 3, which respectively contain the amino acid sequences shown in SEQ ID NOs. 29, 31, and 33.

[0032] In some embodiments, the nucleic acid comprises a polynucleotide encoding a polypeptide comprising an immunoglobulin heavy chain or fragment thereof, comprising VH containing CDR1, 2, and 3, respectively, which have the amino acid sequences shown in SEQ ID NOs. 39, 41, and 43.

[0033] In some embodiments, the nucleic acid comprises a polynucleotide encoding a polypeptide comprising an immunoglobulin heavy chain or fragment thereof, comprising VH containing CDR1, 2, and 3, each having the amino acid sequences shown in SEQ ID NOs. 49, 51, and 53, respectively.

[0034] In some embodiments, the nucleic acid comprises a polynucleotide encoding a polypeptide comprising an immunoglobulin heavy chain or fragment thereof, comprising VH containing CDR1, 2, and 3, which each contain the amino acid sequences shown in SEQ ID NOs. 59, 61, and 63, respectively.

[0035] In some embodiments, the nucleic acid comprises a polynucleotide encoding a polypeptide comprising an immunoglobulin heavy chain or fragment thereof, comprising VH containing CDR1, 2, and 3, which each contain the amino acid sequences shown in SEQ ID NOs. 10, 12, and 13, respectively.

[0036] In some embodiments, the nucleic acid comprises a polynucleotide encoding a polypeptide comprising an immunoglobulin heavy chain or fragment thereof, comprising VH containing CDR1, 2, and 3, each having the amino acid sequences shown in SEQ ID NOs. 20, 22, and 23, respectively.

[0037] In some embodiments, the nucleic acid comprises a polynucleotide encoding a polypeptide comprising an immunoglobulin heavy chain or fragment thereof, comprising VH containing CDR1, 2, and 3, which each contain the amino acid sequences shown in SEQ ID NOs. 30, 32, and 33, respectively.

[0038] In some embodiments, the nucleic acid comprises a polynucleotide encoding a polypeptide comprising an immunoglobulin heavy chain or fragment thereof, comprising VH containing CDR1, 2, and 3, which each contain the amino acid sequences shown in SEQ ID NOs. 40, 42, and 43, respectively.

[0039] In some embodiments, the nucleic acid comprises a polynucleotide encoding a polypeptide comprising an immunoglobulin heavy chain or fragment thereof, comprising VH containing CDR1, 2, and 3, which each contain the amino acid sequences shown in SEQ ID NOs. 50, 52, and 53, respectively.

[0040] In some embodiments, the nucleic acid comprises a polynucleotide encoding a polypeptide comprising an immunoglobulin heavy chain or fragment thereof, comprising VH containing CDR1, 2, and 3, which each contain the amino acid sequences shown in SEQ ID NOs. 60, 62, and 63, respectively.

[0041] In some embodiments, the VH, when paired with the VL, specifically binds to human, mouse, monkey, or canine CD79b, or the VL, when paired with the VH, specifically binds to human, mouse, monkey, or canine CD79b.

[0042] In some embodiments, the immunoglobulin heavy chain or fragment thereof comprises a human immunoglobulin heavy chain fragment (e.g., human IgG1 heavy chain CH1, CH2, and / or CH3, human IgG2 heavy chain CH1, CH2, and / or CH3, or human IgG4 heavy chain CH1, CH2, and / or CH3), and the immunoglobulin light chain or fragment thereof comprises a human immunoglobulin light chain constant region.

[0043] In some embodiments, the nucleic acid encodes a single-chain variable fragment (scFv), a one-arm antibody, a multispecific antibody (e.g., a bispecific antibody), or a chimeric antigen receptor (CAR).

[0044] In some embodiments, the nucleic acid is cDNA.

[0045] In one embodiment, this disclosure relates to a vector comprising one or more nucleic acids described herein.

[0046] In one embodiment, the present disclosure relates to a vector comprising two of the nucleic acids described herein, wherein both vectors encode a VL region and a VH region that bind to CD79b.

[0047] In one embodiment, the present disclosure relates to a pair of vectors each comprising one of the nucleic acids described herein, and both encoding a VL region and a VH region that bind to CD79b.

[0048] In one embodiment, this disclosure relates to a cell comprising a vector as described herein, or a pair of vectors as described herein.

[0049] In some embodiments, the cells are CHO cells.

[0050] In one embodiment, this disclosure relates to a cell comprising one or more nucleic acids described herein.

[0051] In one embodiment, the present disclosure relates to a cell comprising two of the nucleic acids described herein.

[0052] In some embodiments, the two nucleic acids both encode the VL region and the VH region that bind to CD79b.

[0053] In one embodiment, the present disclosure relates to a method for producing an antibody or an antigen-binding fragment thereof, (a) Culturing the cells described herein under conditions sufficient to cause the cells to produce the antibody or the antigen-binding fragment, (b) A method comprising collecting the antibody or antigen-binding fragment produced by the cells.

[0054] In one embodiment, the present disclosure relates to an antibody or antigen-binding fragment thereof that binds to CD79b, It comprises a heavy chain variable region (VH) containing an amino acid sequence that is at least 90% identical to the selected VH sequence, and a light chain variable region (VL) containing an amino acid sequence that is at least 90% identical to the selected VL sequence, wherein the selected VH sequence and the selected VL sequence are (1) The selected VH sequence is sequence number 7 and the selected VL sequence is sequence number 8, (2) The selected VH sequence is sequence number 17 or 69, and the selected VL sequence is sequence number 18 or 70, (3) The selected VH sequence is sequence number 27 and the selected VL sequence is sequence number 28, (4) The selected VH sequence is sequence number 37 or 71, and the selected VL sequence is sequence number 38 or 72, (5) The selected VH sequence is sequence number 47 or 73, and the selected VL sequence is sequence number 48 or 74, and (6) The present invention relates to an antibody or an antigen-binding fragment thereof, wherein the selected VH sequence is one of sequence numbers 57 or 75, and the selected VL sequence is one of sequence numbers 58 or 76.

[0055] In some embodiments, VH includes the sequence of sequence number 7, and VL includes the sequence of sequence number 8.

[0056] In some embodiments, VH includes the sequence of sequence number 17, and VL includes the sequence of sequence number 18.

[0057] In some embodiments, VH includes the sequence of sequence number 27, and VL includes the sequence of sequence number 28.

[0058] In some embodiments, VH includes the sequence of sequence number 37, and VL includes the sequence of sequence number 38.

[0059] In some embodiments, VH includes the sequence of sequence number 47, and VL includes the sequence of sequence number 48.

[0060] In some embodiments, VH includes the sequence of sequence number 57, and VL includes the sequence of sequence number 58.

[0061] In some embodiments, VH includes the sequence of sequence number 69, and VL includes the sequence of sequence number 70.

[0062] In some embodiments, VH includes the sequence of sequence number 71, and VL includes the sequence of sequence number 72.

[0063] In some embodiments, VH includes the sequence of sequence number 73, and VL includes the sequence of sequence number 74.

[0064] In some embodiments, VH includes the sequence of sequence number 75, and VL includes the sequence of sequence number 76.

[0065] In one embodiment, the present disclosure relates to an antibody or antigen-binding fragment thereof that binds to CD79b, The selected VH sequence includes a heavy chain variable region (VH) containing the same VH CDR1, VH CDR2, and VH CDR3 as the selected VH sequence, and a light chain variable region (VL) containing the same VL CDR1, VL CDR2, and VL CDR3 as the selected VL sequence, wherein the selected VH sequence and the selected VL sequence are, (1) The selected VH sequence is sequence number 7 and the selected VL sequence is sequence number 8, (2) The selected VH sequence is sequence number 17 or 69, and the selected VL sequence is sequence number 18 or 70, (3) The selected VH sequence is sequence number 27 and the selected VL sequence is sequence number 28, (4) The selected VH sequence is sequence number 37 or 71, and the selected VL sequence is sequence number 38 or 72, (5) The selected VH sequence is sequence number 47 or 73, and the selected VL sequence is sequence number 48 or 74, and (6) The present invention relates to an antibody or an antigen-binding fragment thereof, wherein the selected VH sequence is one of sequence numbers 57 or 75, and the selected VL sequence is one of sequence numbers 58 or 76.

[0066] In some embodiments, the antibody or its antigen-binding fragment specifically binds to human, mouse, monkey, or canine CD79b.

[0067] In some embodiments, the antibody or its antigen-binding fragment is a humanized antibody or its antigen-binding fragment, a chimeric antibody, a single-chain variable fragment (scFv), a one-arm antibody, and / or a multispecific antibody (e.g., a bispecific antibody).

[0068] In some embodiments, the antibody or antigen-binding fragment comprises human IgG1 Fc, human IgG2 Fc, or human IgG4 Fc.

[0069] In one embodiment, this disclosure relates to an antibody or an antigen-binding fragment that cross-competes with an antibody or an antigen-binding fragment described herein.

[0070] In some embodiments, the antibody or its antigen-binding fragment includes a fragment crystallizable region (Fc region).

[0071] In one embodiment, this disclosure relates to a chimeric antigen receptor (CAR) comprising an antibody or an antigen-binding fragment thereof as described herein.

[0072] In one embodiment, the present disclosure relates to an antibody-drug conjugate comprising an antibody described herein or an antigen-binding fragment thereof covalently bound to a therapeutic agent.

[0073] In some embodiments, the therapeutic agent is a cytotoxic agent or a cell proliferation inhibitor.

[0074] In one embodiment, the present disclosure relates to a method for treating a subject having cancer, comprising administering to the subject a therapeutically effective amount of a composition comprising an antibody or antigen-binding fragment thereof as described herein, a CAR as described herein, or an antibody-drug conjugate as described herein.

[0075] In some embodiments, the cancer is lymphoma, leukemia, breast cancer, gastric cancer, pancreatic cancer, prostate cancer, cervical cancer, endometrial cancer, ovarian cancer, or urothelial carcinoma.

[0076] In some embodiments, the cancer is non-Hodgkin lymphoma (NHL), diffuse large B-cell lymphoma (DLBCL), acute lymphoblastic leukemia (B-ALL), chronic lymphocytic leukemia (CLL), B-cell prelymphocytic leukemia (PLL), splenic lymphoma with choriolymphocytes (SLVL), hairy cell leukemia (HCL), follicular lymphoma (FL), or mantle cell lymphoma (MCL).

[0077] In some embodiments, the subject is further treated with an effective amount of anti-4-1BB antibody, anti-OX40 antibody, anti-PD-1 antibody, anti-CTLA4 antibody, or anti-CD40 antibody.

[0078] In one embodiment, the present disclosure relates to a method for reducing the growth rate of a tumor, comprising contacting tumor cells with an effective amount of a composition comprising an antibody or antigen-binding fragment thereof as described herein, a CAR as described herein, or an antibody-drug conjugate as described herein.

[0079] In one embodiment, the present disclosure relates to a method for killing tumor cells, comprising contacting the tumor cells with an effective amount of a composition comprising an antibody or antigen-binding fragment thereof as described herein, a CAR as described herein, or an antibody-drug conjugate as described herein.

[0080] In one embodiment, the present disclosure relates to a method for increasing an immune response in a subject, comprising administering to the subject an effective amount of a composition comprising an antibody or antigen-binding fragment thereof as described herein, a CAR as described herein, or an antibody-drug conjugate as described herein.

[0081] In one embodiment, the present disclosure relates to a method for treating a subject having an autoimmune disease, comprising administering a therapeutically effective amount of a composition comprising an antibody or antigen-binding fragment thereof as described herein, a CAR as described herein, or an antibody-drug conjugate as described herein.

[0082] In some embodiments, the autoimmune disease is selected from rheumatoid arthritis, psoriasis, multiple sclerosis, immune thrombocytopenic purpura, myasthenia gravis, neuromyelitis optica, IgG4-related disease, systemic lupus erythematosus, lupus nephritis, giant cell arteritis, Takayasu's arteritis, cold agglutinin disease, warm autoimmune hemolytic anemia, and anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis, granulomatosis with polyangiitis (GPA) (Wegener's granulomatosis), microscopic polyangiitis (MPA), inflammatory bowel disease (IBD), or autoreactive pancreatitis.

[0083] In some embodiments, the autoimmune disease is multiple sclerosis, systemic lupus erythematosus, rheumatoid arthritis, inflammatory bowel disease (IBD), or autoreactive pancreatitis.

[0084] In one embodiment, the present disclosure relates to a pharmaceutical composition comprising an antibody or antigen-binding fragment thereof as described herein and a pharmaceutically acceptable carrier.

[0085] In one embodiment, this disclosure relates to a pharmaceutical composition comprising an antibody-drug conjugate described herein and a pharmaceutically acceptable carrier.

[0086] As used herein, the term “cancer” refers to cells that have the capacity for autonomous growth. Examples of such cells include cells that have an abnormal condition or symptom characterized by rapidly proliferating cell growth. The term is intended to include carcinomas, carcinogenic processes, metastatic tissues, and malignantly transformed cells, tissues, or organs, regardless of histopathological type or stage of invasiveness, such as tumors. It also includes malignant tumors of various organ systems, such as the respiratory, cardiovascular, renal, reproductive, hematological, nervous, hepatic, gastrointestinal, and endocrine systems, as well as adenocarcinomas, including most colon cancers, renal cell carcinoma, prostate cancer and / or testicular tumors, non-small cell lung cancer, and small intestine cancer. “Spontaneously occurring” cancer includes any cancer other than cancer experimentally induced by cancer cell transplantation into a subject, and includes, for example, spontaneously occurring cancers, cancers caused by the patient's exposure to a carcinogen, cancers resulting from the insertion of recombinant oncogenes or knockout of tumor suppressor genes, and cancers caused by infections such as viral infections. The term "carcinoma" is recognized in the art and refers to a malignant tumor of epithelial or endocrine tissue. The term also includes carcinosarcoma, which is a malignant tumor composed of cancerous and sarcomatoid tissues. "Adenocarcinoma" refers to a cancer of glandular origin, or a cancer in which tumor cells form recognizable glandular structures. The term "sarcoma" is recognized in the art and refers to a malignant tumor of mesenchymal origin. The term "hematopoietic neoplasm" includes diseases involving hyperplasia / neoplastic cells of hematopoietic origin. Hematopoietic neoplasms may originate from myeloid, lymphoid, or erythroid cells, or their progenitor cells.

[0087] As used herein, the term “antibody” refers to any antigen-binding molecule that comprises at least one (e.g., one, two, three, four, five, or six) complementarity-determining regions (CDRs) (e.g., any of three CDRs from an immunoglobulin light chain or any of three CDRs from an immunoglobulin heavy chain) and is capable of specifically binding to an epitope. Non-limiting examples of antibodies include monoclonal antibodies, polyclonal antibodies, multispecific antibodies (e.g., bispecific antibodies), single-chain antibodies, chimeric antibodies, human antibodies, and humanized antibodies. In some embodiments, an antibody may contain the Fc region of a human antibody. The term antibody also includes derivatives, such as bispecific antibodies, single-chain antibodies, and multispecific antibodies formed from antibody fragments.

[0088] As used herein, the term “antigen-binding fragment” refers to a portion of a full-length antibody, where the portion of the antibody is capable of specifically binding to an antigen. In some embodiments, the antigen-binding fragment contains at least one variable domain (e.g., a variable domain in the heavy chain or a variable domain in the light chain). Non-limiting examples of antibody fragments include, for example, Fab, Fab', F(ab')2, and Fv fragments.

[0089] As used herein, the term “chimeric antibody” refers to an antibody that contains sequences present in at least two different antibodies (e.g., antibodies from two different mammalian species, such as human and non-human antibodies). Non-limiting examples of chimeric antibodies include antibodies containing variable domain sequences (e.g., all or part of the light chain and / or heavy chain variable domain sequences) of a non-human (e.g., mouse, rabbit) antibody and constant domains of a human antibody. Other examples of chimeric antibodies are described herein and are known in the art.

[0090] As used herein, the term “humanized antibody” refers to a non-human antibody that contains minimal sequences derived from non-human (e.g., mouse, rabbit) immunoglobulins and sequences derived from human immunoglobulins. In non-limiting examples, a humanized antibody is a human antibody (recipient antibody) in which the hypervariable (e.g., CDR) region residues of the recipient antibody are replaced by hypervariable (e.g., CDR) region residues from a non-human antibody (e.g., donor antibody), e.g., mouse, rat, or rabbit antibody, having desired specificity, affinity, and capability. In some embodiments, the Fv framework residues of human immunoglobulin are replaced by corresponding non-human (e.g., mouse, rabbit) immunoglobulin residues. In some embodiments, the humanized antibody may contain residues not found in the recipient antibody or donor antibody. These modifications may be added to further improve the performance of the antibody. In some embodiments, the humanized antibody contains at least one, typically two, substantially all, variable domains, where all or substantially all of the hypervariable loop (CDR) corresponds to the hypervariable loop of a non-human (e.g., mouse, rabbit) immunoglobulin, and all or substantially all of the framework region is the framework region of a human immunoglobulin. The humanized antibody may also contain at least a portion of the immunoglobulin constant region (Fc), typically at least a portion of the immunoglobulin constant region (Fc) of a human immunoglobulin. Humanized antibodies can be produced using molecular biological methods known in the art. Non-limiting examples of methods for generating humanized antibodies are described herein.

[0091] As used herein, the terms “subject” and “patient” are used interchangeably throughout this specification and refer to animals, humans, or non-humans receiving treatment by the methods of the present invention. The present invention is intended for veterinary and non-veterinary uses. Human patients may be adults or young persons (e.g., humans under 18 years of age). In addition to humans, patients include, but are not limited to, mice, rats, hamsters, guinea pigs, rabbits, ferrets, cats, dogs, and primates. For example, non-human primates (e.g., monkeys, chimpanzees, gorillas, etc.), rodents (e.g., rats, mice, gerbils, hamsters, ferrets, rabbits), rabbits, pigs (e.g., pigs, miniature pigs), equids, canids, felids, bovids, and other livestock, farm and zoo animals.

[0092] As used herein, when referring to antibodies, the terms “specifically bind” and “specifically bind” mean that the antibody interacts with its target molecule (e.g., CD79b), preferably another molecule, because the interaction depends on the presence of a specific structure (i.e., an antigenic determinant or epitope) on the target molecule. In other words, reagents generally recognize and bind to molecules containing a specific structure, rather than all molecules. An antibody that specifically binds to a target molecule may be called a target-specific antibody. For example, an antibody that specifically binds to the CD79b molecule may be called a CD79b-specific antibody or an anti-CD79b antibody.

[0093] As used herein, the terms “polypeptide,” “peptide,” and “protein” are interchangeable and refer to amino acid polymers of any length comprising at least two amino acids.

[0094] As used herein, the terms “polynucleotide,” “nucleic acid molecule,” and “nucleic acid sequence” are used interchangeably herein to refer to nucleotide polymers of any length comprising at least two nucleotides, and include, without limitation, DNA, RNA, DNA / RNA hybrids, and their modifications.

[0095] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those generally understood by a person of ordinary skill in the art to which the present invention pertains. While methods and materials for use in the present invention are described herein, other suitable methods and materials known in the art may also be used. Materials, methods, and examples are illustrative and not limiting. All publications, patent applications, patents, sequences, database entries, and other references referenced herein are incorporated by reference as a whole. In case of any conflict, this specification, including definitions, shall prevail.

[0096] Other features and advantages of the present invention will become apparent from the following detailed description and drawings, as well as the claims. [Brief explanation of the drawing]

[0097] [Figure 1] This shows the ELISA binding affinity of the anti-CD79b antibody to the human CD79b recombinant protein. [Figure 2] This shows the ELISA binding affinity of the anti-CD79b antibody to the cynomolgus monkey CD79b recombinant protein. [Figure 3] This shows the BLI trace of the binding of the anti-CD79b antibody to the human CD79b recombinant protein. [Figure 4] This shows the relative internalization of anti-CD79b antibodies from the cell surface of Ramos cells. [Figure 5] This shows the quantification of anti-CD79b antigen density on the surface of malignant B tumor cells and normal B cells. [Figure 6] This shows the binding affinity of the anti-CD79b antibody to BJAB cells. [Figure 7] This shows the binding affinity of the anti-CD79b antibody to Ramos cells. [Figure 8] This shows the binding affinity of the anti-CD79b antibody to Daudi cells. [Figure 9] This shows the binding affinity of the anti-CD79b antibody to SU-DHL-4 cells. [Figure 10]This shows the binding affinity of the anti-CD79b antibody to Nalm-6 cells. [Figure 11] This shows the binding affinity of the anti-CD79b antibody to donor 2890. [Figure 12] This shows the binding affinity of the anti-CD79b antibody to donor 2235. [Figure 13] This shows the binding affinity of the anti-CD79b antibody to donor 889. [Figure 14] This shows the binding affinity of the anti-CD79b antibody to donor 356. [Figure 15] This shows the binding affinity of the anti-CD79b antibody to CLL donor 5716. [Figure 16] This shows the binding affinity of the anti-CD79b antibody to CLL donor 0255. [Figures 17A-17B] This shows the binding of the anti-CD79b antibody to both the long and short isoforms of CD79b. [Figure 18] This shows the ELISA binding of a humanized anti-CD79b antibody to recombinant human CD79b ECD. [Figure 19] This shows the binding of a humanized anti-CD79b antibody to cell lines expressing endogenous CD79b. [Figure 20] This lists the CDR sequences of anti-CD79b antibodies as defined by the Kabat definition. [Figure 21] This lists the CDR sequences of anti-CD79b antibodies as defined by the Kotia definition. [Figure 22] The selected amino acid sequences discussed in this disclosure are listed below. [Modes for carrying out the invention]

[0098] The B lymphocyte antigen receptor is a multimeric complex containing surface immunoglobulin (Ig), an antigen-specific component. Surface Ig non-covalently associates with two other proteins, CD79a and CD79b, which are necessary for the expression and function of the B cell antigen receptor. CD79 is the signaling component of the B cell receptor and functions as a covalent heterodimer containing CD79a (i.e., Ig-α or MB1) and CD79b (i.e., Ig-β or B29). CD79b contains an extracellular immunoglobulin (Ig) domain, a transmembrane domain, an intracellular signaling domain, and an immunoreceptor tyrosine-based activation motif (ITAM) domain. CD79b expression has been detected in almost all patients with non-Hodgkin lymphoma (NHL), acute lymphoblastic leukemia (ALL), and chronic lymphocytic leukemia (CLL).

[0099] This disclosure provides examples of an antibody that binds to CD79b and its antigen-binding fragment. CD79b

[0100] CD79 consists of CD79a and CD79b components, which are expressed almost exclusively on B cells and B cell neoplasms. The expression of CD79a and CD79b precedes immunoglobulin (Ig) heavy chain gene rearrangement and CD20 expression during B cell development, and disappears later than CD20 in the later stages of B cell differentiation (plasma cells). Therefore, antibodies against CD79a and CD79b are useful in the differential diagnosis of B cell neoplasms and T cell neoplasms or myeloneoplasms, or between L and H lymphocyte-dominant Hodgkin lymphoma and classical Hodgkin lymphoma. In addition, anti-CD79a and anti-CD79b antibodies are useful markers for the diagnosis of progenitor B-cell acute lymphoblastic leukemia (pre-B-ALL) because many of these tumors are negative for other B cell markers such as CD20 and CD45RA.

[0101] CD79 is physiologically and exclusively expressed in the majority of B-cell NHLs, including not only mature B cells and DLBCL (90-100%), but also acute lymphoblastic leukemia (B-ALL), chronic lymphocytic leukemia (CLL), B-cell prelymphocytic leukemia (PLL), splenic lymphoma with choriolymphocytes (SLVL), hairy cell leukemia (HCL), follicular lymphoma (FL), and mantle cell lymphoma (MCL), making it an interesting therapeutic target for antibodies.

[0102] CD79 associates with cell surface immunoglobulin (sIg) for antigen recognition to form the B cell antigen receptor (BCR) complex, which plays a crucial role in B cell maturation and activation. CD79 consists of α (CD79a) and β (CD79b) heterodimers that function as BCR signaling components. Both subunits of CD79 contain a single extracellular Ig domain, a transmembrane domain, and an intracellular signaling domain that initiates BCR signaling after antigen binding, ultimately leading to B cell activation, antigen presentation, cytokine production, and cell proliferation and differentiation.

[0103] Antigen binding of the BCR induces its internalization and transport to the major histocompatibility complex class II (MHCII) compartment, a lysosome-like compartment, for class II antigen presentation by B cells. This intracellular transport is particularly interesting because it allows drugs to be delivered directly to the lysosome compartment of target cells, enhancing cytotoxic activity and enabling the use of more stable linkers that are cleaved in the MHCII compartment.

[0104] Detailed reviews of CD79b and its function are incorporated as a whole in Chu, Peiguo G., and Daniel A. Arber. “CD79: a review.” Applied Immunohistochemistry & Molecular Morphology 9.2 (2001): 97-106, and Bourbon, Estelle, and Gilles Salles. “Polatuzumab vedotin: an investigational anti-CD79b antibody drug conjugate for the treatment of diffuse large B-cell lymphoma.” Expert Opinion on Investigational Drugs 29.10 (2020): 1079-1088.

[0105] This disclosure provides several anti-CD79b antibodies, their antigen-binding fragments, and methods for using these anti-CD79b antibodies and antigen-binding fragments to inhibit tumor growth, treat cancer, and treat autoimmune diseases. Antibody and antigen-binding fragments

[0106] This disclosure provides an anti-CD79b antibody and its antigen-binding fragment. Generally, an antibody (also called an immunoglobulin) consists of two classes of polypeptide chains, a light chain and a heavy chain. The non-limiting antibodies of this disclosure may be a 4-immunoglobulin chain antibody containing two heavy chains and two light chains. The heavy chain of the antibody may be any isotype, including IgM, IgG, IgE, IgA, or IgD, or any subisotype, including IgG1, IgG2, IgG2a, IgG2b, IgG3, IgG4, IgE1, IgE2, etc. The light chain may be a kappa light chain or a lambda light chain. The antibody may contain two identical copies of the light chain and two identical copies of the heavy chain. Each heavy chain contains one variable domain (or variable region, VH) and multiple constant domains (or constant regions), which are bound to each other via disulfide bonds within their constant domains to form the “stem” of the antibody. Each light chain contains one variable domain (or variable region, VL) and one constant domain (or constant region), and each is bonded to a heavy chain via a disulfide bond. The variable region of each light chain is aligned with the variable region of the heavy chain to which it is bonded. The variable regions of both the light and heavy chains contain three hypervariable regions sandwiched between more conserved framework regions (FRs).

[0107] These hypervariable regions are known as complementarity-determining regions (CDRs) and form loops containing the antibody's primary antigen-binding surface. The four framework regions primarily adopt a β-sheet conformation, with the CDRs forming loops connecting the β-sheet structures, and in some cases forming parts of them. The CDRs in each chain are held in close proximity by the framework regions and, together with CDRs from other chains, contribute to the formation of the antigen-binding region.

[0108] Methods for identifying the CDR region of an antibody by analyzing its amino acid sequence are well-known, and numerous definitions of CDRs are commonly used. The Kabat definition is based on sequence variability, while the Cotia definition is based on the location of the structural loop region. These methods and definitions are incorporated herein by reference, for example, Martin, “Protein sequence and structure analysis of antibody variable domains,” Antibody engineering, Springer Berlin Heidelberg, 2001. 422-439; Abhinandan, et al. “Analysis and improvements to Kabat and structurally correct numbering of antibody variable domains,” Molecular immunology 45.14 (2008): 3832-3839; Wu, TT and Kabat, EA (1970) J. Exp. Med. 132: 211-250; Martin et al., Methods Enzymol. 203:121-53 (1991); Morea et al., Biophys Chem. 68(1-3):9-16 (Oct. 1997); Morea et al., J Mol Biol. This is described in 275(2):269-94 (Jan. 1998), Chothia et al., Nature 342(6252):877-83 (Dec. 1989), and Ponomarenko and Bourne, BMC Structural Biology 7:64 (2007).

[0109] CDRs are important for recognizing the epitopes of antigens. As used herein, an “epitope” is the smallest portion of a target molecule to which the antigen-binding domain of an antibody can specifically bind. The minimum size of an epitope can be about 3, 4, 5, 6, or 7 amino acids, but these amino acids do not need to be a continuous linear sequence of the primary structure of the antigen, as the epitope may depend on the three-dimensional arrangement of the antigen based on the secondary and tertiary structures of the antigen.

[0110] In some embodiments, the antibody is an intact immunoglobulin molecule (e.g., IgG1, IgG2a, IgG2b, IgG3, IgM, IgD, IgE, IgA). The IgG subclasses (IgG1, IgG2, IgG3, and IgG4) are highly conserved, differing in their constant regions, particularly the hinge and upper CH2 domain. The sequences and differences of IgG subclasses are known in the art and are incorporated herein by reference, for example, in Vidarsson, et al., “IgG subclasses and allotypes: from structure to effector functions.” Frontiers in immunology 5 (2014); Irani, et al., “Molecular properties of human IgG subclasses and their implications for designing therapeutic monoclonal antibodies against infectious diseases.” Molecular immunology 67.2 (2015): 171-182; and Shakib, Farouk, ed. The human IgG subclasses: molecular analysis of structure, function and regulation. Elsevier, 2016.

[0111] The antibody may be an immunoglobulin molecule derived from any species (e.g., human, rodent, mouse, camelid, rabbit). The antibodies disclosed herein include, but are not limited to, polyclonal antibodies, monoclonal antibodies, monospecific antibodies, multispecific antibodies, and chimeric antibodies containing an immunoglobulin-binding domain fused to another polypeptide. The terms “antigen-binding domain” or “antigen-binding fragment” refer to a portion of the antibody that retains the specific binding activity of the intact antibody, i.e., any portion of the antibody that is specifically capable of binding to an epitope on the target molecule of the intact antibody. This includes, for example, Fab, Fab', F(ab')2, and variants of these fragments. Thus, in some embodiments, the antibody or its antigen-binding fragment may be, for example, scFv, Fv, Fd, bispecific antibodies, single-chain antibody molecules, multispecific antibodies formed from antibody fragments, and any polypeptide that is an antibody-binding domain or contains a binding domain homologous to an antibody-binding domain. Non-limiting examples of antigen-binding domains include, for example, the heavy and / or light chain CDRs of an intact antibody, the heavy and / or light chain variable regions of an intact antibody, the full-length heavy or light chain of an intact antibody, or individual CDRs from the heavy or light chain of an intact antibody.

[0112] In some embodiments, the antigen-binding fragment can form part of a chimeric antigen receptor (CAR). In some embodiments, the scFV has one heavy chain variable domain and one light chain variable domain. In some embodiments, the scFV has two heavy chain variable domains and two light chain variable domains. Anti-CD79b antibody and antigen-binding fragment

[0113] This disclosure provides antibodies and antigen-binding fragments that specifically bind to CD79b (e.g., human CD79b). The antibodies and antigen-binding fragments described herein can bind to CD79b. These antibodies may be agonists or antagonists to CD79b-mediated BCR signaling. In some embodiments, the antibodies and antigen-binding fragments can bind to the extracellular domain of human CD79b.

[0114] This disclosure provides, for example, anti-CD79b antibodies 22D10, 23D8, 29C3, 44G2, 48H10, 57B9, their chimeric antibodies, and their humanized antibodies.

[0115] The CDR sequences of 22D10 antibodies and 22D10-derived antibodies (e.g., humanized antibodies) include the heavy chain variable domain CDRs of SEQ ID NOs. 9, 11, and 13, and the light chain variable domain CDRs of SEQ ID NOs. 14-16, as defined by the Kabat definition. The CDRs may also be defined by the Cotia definition. Under the Cotia definition, the heavy chain variable domain CDR sequences are those shown in SEQ ID NOs. 10, 12, and 13, and the light chain variable domain CDR sequences are those shown in SEQ ID NOs. 14-16.

[0116] Similarly, the CDR sequences of the 23D8 antibody and the 23D8-derived antibody include the heavy chain variable domain CDRs of SEQ ID NOs. 19, 21, and 23, and the light chain variable domain CDRs of SEQ ID NOs. 24-26, as defined by the Kabat definition. Under the Kotia definition, the heavy chain variable domain CDR sequences are those shown in SEQ ID NOs. 20, 22, and 23, and the light chain variable domain CDRs are those shown in SEQ ID NOs. 24-26.

[0117] The CDR sequences of 29C3 antibodies and 29C3-derived antibodies include the heavy chain variable domain CDRs of SEQ ID NOs. 29, 31, and 33, and the light chain variable domain CDRs of SEQ ID NOs. 34-36, as defined by the Kabat definition. Under the Kotia definition, the heavy chain variable domain CDR sequences are those shown in SEQ ID NOs. 30, 32, and 33, and the light chain variable domain CDRs are those shown in SEQ ID NOs. 34-36.

[0118] The CDR sequences of 44G2 antibodies and 44G2-derived antibodies include the heavy chain variable domain CDRs of SEQ ID NOs. 39, 41, and 43, and the light chain variable domain CDRs of SEQ ID NOs. 44-46, as defined by the Kabat definition. Under the Kotia definition, the heavy chain variable domain CDR sequences are those shown in SEQ ID NOs. 40, 42, and 43, and the light chain variable domain CDRs are those shown in SEQ ID NOs. 44-46.

[0119] The CDR sequences of 48H10 antibodies and 48H10-derived antibodies include the heavy chain variable domain CDRs of SEQ ID NOs. 49, 51, and 53, and the light chain variable domain CDRs of SEQ ID NOs. 54–56, as defined by the Kabat definition. Under the Kotia definition, the heavy chain variable domain CDR sequences are those shown in SEQ ID NOs. 50, 52, and 53, and the light chain variable domain CDRs are those shown in SEQ ID NOs. 54–56.

[0120] The CDR sequences of the 57B9 antibody and the 57B9-derived antibody include the heavy chain variable domain CDRs of SEQ ID NOs. 59, 61, and 63, and the light chain variable domain CDRs of SEQ ID NOs. 64-66, as defined by the Kabat definition. Under the Kotia definition, the heavy chain variable domain CDR sequences are those shown in SEQ ID NOs. 60, 62, and 63, and the light chain variable domain CDRs are those shown in SEQ ID NOs. 64-66.

[0121] The amino acid sequence of the heavy chain variable region of the 22D10 antibody is shown in SEQ ID NO: 7. The amino acid sequence of the light chain variable region of the 22D10 antibody is shown in SEQ ID NO: 8.

[0122] The amino acid sequence of the heavy chain variable region of the 23D8 antibody is shown in SEQ ID NO: 17. The amino acid sequence of the light chain variable region of the 23D8 antibody is shown in SEQ ID NO: 18.

[0123] The amino acid sequence of the heavy chain variable region of the 29C3 antibody is shown in SEQ ID NO: 27. The amino acid sequence of the light chain variable region of the 29C3 antibody is shown in SEQ ID NO: 28.

[0124] The amino acid sequence of the heavy chain variable region of the 44G2 antibody is shown in SEQ ID NO: 37. The amino acid sequence of the light chain variable region of the 44G2 antibody is shown in SEQ ID NO: 38.

[0125] The amino acid sequence of the heavy chain variable region of the 48H10 antibody is shown in SEQ ID NO: 47. The amino acid sequence of the light chain variable region of the 48H10 antibody is shown in SEQ ID NO: 48.

[0126] The amino acid sequence of the heavy chain variable region of the 57B9 antibody is shown in SEQ ID NO: 57. The amino acid sequence of the light chain variable region of the 57B9 antibody is shown in SEQ ID NO: 58.

[0127] In some embodiments, the anti-CD79b antibody is a humanized antibody. In some embodiments, the anti-CD79b antibody is humanized 23D8, 44G2, 48H10, or 57B9.

[0128] The amino acid sequence of the heavy chain variable region of the humanized 23D8 antibody is shown in SEQ ID NO: 69. The amino acid sequence of the light chain variable region of the 23D8 antibody is shown in SEQ ID NO: 70.

[0129] The amino acid sequence of the heavy chain variable region of the humanized 44G2 antibody is shown in SEQ ID NO: 71. The amino acid sequence of the light chain variable region of the 44G2 antibody is shown in SEQ ID NO: 72.

[0130] The amino acid sequence of the heavy chain variable region of the humanized 48H10 antibody is shown in SEQ ID NO: 73. The amino acid sequence of the light chain variable region of the 48H10 antibody is shown in SEQ ID NO: 74.

[0131] The amino acid sequence of the heavy chain variable region of the humanized 57B9 antibody is shown in SEQ ID NO: 75. The amino acid sequence of the light chain variable region of the 57B9 antibody is shown in SEQ ID NO: 76.

[0132] The amino acid sequences of the heavy chain variable region and light chain variable region of the modified antibody are also provided. In some embodiments, the heavy chain variable region is at least 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% identical to any of SEQ ID NOs: 7, 17, 27, 37, 47, 57, 69, 71, 73, and 75. In some embodiments, the light chain variable region is at least 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% identical to any of SEQ ID NOs: 8, 18, 28, 38, 48, 58, 70, 72, 74, and 76. The heavy chain variable region sequence can be paired with a corresponding light chain variable region sequence, both of which bind to CD79b.

[0133] The humanization percentage refers to the percentage of identity of the heavy or light chain variable region sequence compared to the human antibody sequence in the International Immunogenetic Information System (IMGT) database. In some embodiments, the humanization percentage is higher than 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, or 95%. Detailed descriptions of methods for determining the humanization percentage and the top hit are known in the art and are, for example, described in Jones, et al. “The INNs and outs of antibody nonproprietary names.” MAbs. Vol. 8. No. 1. Taylor & Francis, 2016, which are incorporated herein by reference in their entirety. Higher humanization percentages often offer various advantages, such as being safer and more effective in humans, being more tolerable in human subjects, and / or having a lower potential for side effects. In some embodiments, the variable regions are entirely human and are derived, for example, from human heavy chain immunoglobulin loci (e.g., recombinants of human IGHV, human IGHD, and human IGHJ genes) and / or human kappa chain immunoglobulin loci (e.g., recombinants of human IGKV and human IGKJ genes).

[0134] Furthermore, in some embodiments, the antibodies or antigen-binding fragments described herein may contain one, two, or three heavy chain variable region CDRs selected from the group of SEQ ID NOs: 9, 11, 13, 19, 21, 23, 29, 31, 33, 39, 41, 43, 49, 51, 53, 59, 61, 63, 10, 12, 13, 20, 22, 23, 30, 32, 33, 40, 42, 43, 50, 52, 53, 60, 62, 63, and / or one, two, or three light chain variable region CDRs selected from the group of SEQ ID NOs: 14-16, 24-26, 34-36, 44-46, 54-56, and 64-66.

[0135] In some embodiments, the antibody may have a heavy chain variable region (VH) comprising complementarity-determining regions (CDRs) 1, 2, and 3, wherein the CDR1 region comprises or consists of an amino acid sequence that is at least 80%, 85%, 90%, or 95% identical to a selected VH CDR1 amino acid sequence; the CDR2 region comprises or consists of an amino acid sequence that is at least 80%, 85%, 90%, or 95% identical to a selected VH CDR2 amino acid sequence; and the CDR3 region comprises or consists of an amino acid sequence that is at least 80%, 85%, 90%, or 95% identical to a selected VH CDR3 amino acid sequence. In some embodiments, the antibody may have a light chain variable region (VL) comprising CDR1, 2, and 3, of which the CDR1 region comprises or consists of an amino acid sequence that is at least 80%, 85%, 90%, or 95% identical to the selected VL CDR1 amino acid sequence; the CDR2 region comprises or consists of an amino acid sequence that is at least 80%, 85%, 90%, or 95% identical to the selected VL CDR2 amino acid sequence; and the CDR3 region comprises or consists of an amino acid sequence that is at least 80%, 85%, 90%, or 95% identical to the selected VL CDR3 amino acid sequence. The selected VH CDR1, 2, and 3 amino acid sequences and the selected VL CDR1, 2, and 3 amino acid sequences are shown in Figure 20 (Kavat CDR) and Figure 21 (Cotia CDR).

[0136] In some embodiments, the antibody or antigen-binding fragment described herein may contain heavy chain variable domains containing one, two, or three of the CDRs of SEQ ID NO: 9, SEQ ID NO: 11, SEQ ID NO: 13, SEQ ID NO: 13, SEQ ID NO: 9, SEQ ID NO: 9, SEQ ID NO: 9, SEQ ID NO: 9, SEQ ID NO: 11, SEQ ID NO: 11, SEQ ID NO: 11, SEQ ID NO: 13

[0137] In some embodiments, the antibody or antigen-binding fragment described herein may contain heavy chain variable domains containing one, two, or three of the CDRs of SEQ ID NO: 19, SEQ ID NO: 21, SEQ ID NO: 23, SEQ ID NO: 23, SEQ ID NO: 23, SEQ ID NO: 123, SEQ ID NO: 13, SEQ ID NO: 23, SEQ ID NO: 23, SEQ ID NO: 13, SEQ ID NO: 23, SEQ ID NO: 23, SEQ ID NO: 23, SEQ ID NO: 13, SEQ ID NO: 23, SEQ ID NO: 23, SEQ ID NO: 23, SEQ ID NO: 13, SEQ ID NO: 23, SEQ ID NO: 23, SEQ ID NO: 23, SEQ ID NO: 23, SEQ ID NO: 13, SEQ ID NO: 23, SEQ ID NO: 23, SEQ ID NO: 23, SEQ ID NO: 23, SEQ ID NO: 23, SEQ ID NO: 23, SEQ ID NO: 23, SEQ ID NO: 23, SEQ ID NO: 23, SEQ ID NO: 23, SEQ ID NO: 23, SEQ ID NO: 23, SEQ ID NO: 23, SEQ ID NO: 23, S

[0138] In some embodiments, the antibody or antigen-binding fragment described herein may contain heavy chain variable domains containing one, two, or three of the CDRs of SEQ ID NO: 29, SEQ ID NO: 31, and SEQ ID NO: 33, which have 0, 1, or 2 amino acid insertions, deletions, or substitutions.

[0139] In some embodiments, the antibody or antigen-binding fragment described herein may contain heavy chain variable domains containing one, two, or three of the CDRs of SEQ ID NO: 39, SEQ ID NO: 41, SEQ ID NO: 43, and SEQ ID NO: 43, which have 0, 1, or 2 amino acid insertions, deletions, or substitutions.

[0140] In some embodiments, the antibody or antigen-binding fragment described herein may contain a heavy chain variable domain containing one, two, or three of the CDRs of SEQ ID NO: 49, SEQ ID NO: 51, and SEQ ID NO: 53, which have 0, 1, or 2 amino acid insertions, deletions, or substitutions.

[0141] In some embodiments, the antibody or antigen-binding fragment described herein may contain heavy chain variable domains containing one, two, or three of the CDRs of SEQ ID NO: 59, SEQ ID NO: 61, and SEQ ID NO: 63, which have 0, 1, or 2 amino acid insertions, deletions, or substitutions.

[0142] In some embodiments, the antibody or antigen-binding fragment described herein may contain heavy chain variable domains containing one, two, or three of the CDRs of SEQ ID NO: 10 having 0, 1, or 2 amino acid insertions, deletions, or substitutions, SEQ ID NO: 12 having 0, 1, or 2 amino acid insertions, deletions, or substitutions, and SEQ ID NO: 13 having 0, 1, or 2 amino acid insertions, deletions, or substitutions.

[0143] In some embodiments, the antibody or antigen-binding fragment described herein may contain heavy chain variable domains containing one, two, or three of the CDRs of SEQ ID NO: 20 having 0, 1, or 2 amino acid insertions, deletions, or substitutions, SEQ ID NO: 22 having 0, 1, or 2 amino acid insertions, deletions, or substitutions, or SEQ ID NO: 23 having 0, 1, or 2 amino acid insertions, deletions, or substitutions.

[0144] In some embodiments, the antibody or antigen-binding fragment described herein may contain heavy chain variable domains containing one, two, or three of the CDRs of SEQ ID NO: 30 having 0, 1, or 2 amino acid insertions, deletions, or substitutions, SEQ ID NO: 32 having 0, 1, or 2 amino acid insertions, deletions, or substitutions, and SEQ ID NO: 33 having 0, 1, or 2 amino acid insertions, deletions, or substitutions.

[0145] In some embodiments, the antibody or antigen-binding fragment described herein may contain heavy chain variable domains containing one, two, or three of the CDRs of SEQ ID NO: 40 having 0, 1, or 2 amino acid insertions, deletions, or substitutions, SEQ ID NO: 42 having 0, 1, or 2 amino acid insertions, deletions, or substitutions, and SEQ ID NO: 43 having 0, 1, or 2 amino acid insertions, deletions, or substitutions.

[0146] In some embodiments, the antibody or antigen-binding fragment described herein may contain heavy chain variable domains containing one, two, or three of the CDRs of SEQ ID NO: 50, SEQ ID NO: 52, SEQ ID NO: 53, which have 0, 1, or 2 amino acid insertions, deletions, or substitutions.

[0147] In some embodiments, the antibody or antigen-binding fragment described herein may contain heavy chain variable domains containing one, two, or three of the CDRs of SEQ ID NO: 60 having 0, 1, or 2 amino acid insertions, deletions, or substitutions, SEQ ID NO: 62 having 0, 1, or 2 amino acid insertions, deletions, or substitutions, and SEQ ID NO: 63 having 0, 1, or 2 amino acid insertions, deletions, or substitutions.

[0148] In some embodiments, the antibody or antigen-binding fragment described herein may contain a light chain variable domain containing one, two, or three of the CDRs of SEQ ID NO: 14, SEQ ID NO: 15, SEQ ID NO: 16

[0149] In some embodiments, the antibody or antigen-binding fragment described herein may contain a light chain variable domain containing one, two, or three of the CDRs of SEQ ID NO: 24, SEQ ID NO: 25, SEQ ID NO: 26

[0150] In some embodiments, the antibody or antigen-binding fragment described herein may contain a light chain variable domain containing one, two, or three of the CDRs of SEQ ID NO: 34, SEQ ID NO: 35, and SEQ ID NO: 36, which have 0, 1, or 2 amino acid insertions, deletions, or substitutions.

[0151] In some embodiments, the antibody or antigen-binding fragment described herein may contain a light chain variable domain containing one, two, or three of the CDRs of SEQ ID NO: 44, SEQ ID NO: 45, and SEQ ID NO: 46, which have 0, 1, or 2 amino acid insertions, deletions, or substitutions.

[0152] In some embodiments, the antibody or antigen-binding fragment described herein may contain a light chain variable domain containing one, two, or three of the CDRs of SEQ ID NO: 54, SEQ ID NO: 55, SEQ ID NO: 56, and SEQ ID NO: 56, which have 0, 1, or 2 amino acid insertions, deletions, or substitutions.

[0153] In some embodiments, the antibody or antigen-binding fragment described herein may contain a light chain variable domain containing one, two, or three of the CDRs of SEQ ID NO: 64, SEQ ID NO: 65, and SEQ ID NO: 66, which have 0, 1, or 2 amino acid insertions, deletions, or substitutions.

[0154] Insertions, deletions, and substitutions can be performed within the CDR sequence or at one or both ends of the CDR sequence. In some embodiments, the CDR is determined based on the Kabat definition. In some embodiments, the CDR is determined based on the Kotia definition. In some embodiments, the CDR is determined based on a combination of the Kabat and Kotia definitions.

[0155] This disclosure also provides antibodies or antigen-binding fragments thereof that bind to CD79b. The antibody or antigen-binding fragment comprises a heavy chain variable region (VH) comprising or consisting of an amino acid sequence that is at least 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% identical to a selected VH sequence, and a light chain variable region (VL) comprising or consisting of an amino acid sequence that is at least 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% identical to a selected VL sequence. In some embodiments, the selected VH sequence is SEQ ID NO: 7 and the selected VL sequence is SEQ ID NO: 8. In some embodiments, the selected VH sequence is SEQ ID NO: 17 and the selected VL sequence is SEQ ID NO: 18. In some embodiments, the selected VH sequence is SEQ ID NO: 27 and the selected VL sequence is SEQ ID NO: 28. In some embodiments, the selected VH sequence is SEQ ID NO: 37 and the selected VL sequence is SEQ ID NO: 38. In some embodiments, the selected VH sequence is sequence number 47 and the selected VL sequence is sequence number 48. In some embodiments, the selected VH sequence is sequence number 57 and the selected VL sequence is sequence number 58. In some embodiments, the selected VH sequence is sequence number 69 and the selected VL sequence is sequence number 70. In some embodiments, the selected VH sequence is sequence number 71 and the selected VL sequence is sequence number 72. In some embodiments, the selected VH sequence is sequence number 73 and the selected VL sequence is sequence number 74. In some embodiments, the selected VH sequence is sequence number 75 and the selected VL sequence is sequence number 76.

[0156] This disclosure also provides antibodies or antigen-binding fragments thereof that can compete with the antibodies described herein. In some embodiments, such antibodies or antigen-binding fragments can bind to the same epitopes as the antibodies described herein.

[0157] This disclosure also provides antibodies or antigen-binding fragments that cross-compete with any antibody or antigen-binding fragment described herein. Cross-competition assays are known in the art and, for example, are described in Moore et al., “Antibody cross-competition analysis of the human immunodeficiency virus type 1 gp120 exterior envelope glycoprotein.” Journal of virology 70.3 (1996): 1863-1872, which is incorporated herein by reference in whole. In one embodiment, this disclosure also provides antibodies or antigen-binding fragments that bind to the same epitope or region as any antibody or antigen-binding fragment described herein. Epitope binning assays are known in the art and, for example, are described in Estep et al., “High throughput solution-based measurement of antibody-antigen affinity and epitope binning.” MAbs. Vol. 5. No. 2. Taylor & Francis, 2013, which is incorporated herein by reference in whole.

[0158] To determine the percentage of identity between two amino acid sequences or two nucleic acid sequences, the sequences are aligned for the purpose of optimal comparison (for example, gaps may be introduced in one or both of the first and second amino acid or nucleic acid sequences for optimal alignment, and non-homologous sequences may be ignored for the purpose of comparison). Next, amino acid residues or nucleotides at corresponding amino acid or nucleotide positions are compared. If a position in the first sequence is occupied by the same amino acid residue or nucleotide as the corresponding position in the second sequence, the molecules are identical at that position. The percentage of identity between the two sequences is a function of the number of identical positions shared by the sequences, taking into account the number of gaps that need to be introduced for optimal alignment of the two sequences and the length of each gap. For example, the comparison of sequences and the determination of the percentage of identity between two sequences can be achieved using a Blossum62 scoring matrix with a gap penalty of 12, a gap expansion penalty of 4, and a frameshift gap penalty of 5.

[0159] This disclosure also provides nucleic acids comprising polynucleotides encoding polypeptides containing immunoglobulin heavy chains or immunoglobulin light chains. The immunoglobulin heavy chains or immunoglobulin light chains contain a CDR as shown in Figure 20 or Figure 21, or have a sequence as shown in Figure 22. When a polypeptide is paired with a corresponding polypeptide (e.g., a corresponding heavy chain variable region or a corresponding light chain variable region), the paired polypeptide binds to CD79b (e.g., human CD79b).

[0160] The anti-CD79b antibody and antigen-binding fragment may be antibody variants (derivatives and conjugates) of the antibody or antibody fragment, and multispecific (e.g., bispecific) antibodies or antibody fragments. Additional antibodies provided herein include polyclonal antibodies, monoclonal antibodies, multimeric antibodies, multispecific (e.g., bispecific) antibodies, humanized antibodies, chimeric antibodies (e.g., human-mouse chimeric antibodies), single-chain antibodies, intracellularly produced antibodies (i.e., intracellular antibodies), and their antigen-binding fragments. The antibody or its antigen-binding fragment may be of any type (e.g., IgG, IgE, IgM, IgD, IgA, and IgY), class (e.g., IgG1, IgG2, IgG3, IgG4, IgA1, and IgA2), or subclass. In some embodiments, the antibody or its antigen-binding fragment is an IgG antibody or its antigen-binding fragment.

[0161] Antibody fragments are suitable for use in the provided method, provided they retain the desired affinity and specificity of the full-length antibody. Therefore, an antibody fragment that binds to CD79b retains its ability to bind to CD79b. The Fv fragment is an antibody fragment containing a complete antigen recognition and binding site. This region consists of a dimer in which one heavy chain variable domain and one light chain variable domain are tightly associated, for example, a dimer that can essentially covalently bind in scFv. It is in this arrangement that the three CDRs of each variable domain interact to define the antigen-binding site on the surface of the VH-VL dimer. Collectively, the six CDRs, or a subset thereof, confer antigen-binding specificity to the antibody. However, a single variable domain (or half of an Fv containing only the three antigen-specific CDRs) can also recognize and bind to the antigen, although usually with lower affinity than the entire binding site.

[0162] A single-stranded Fv or (scFv) antibody fragment contains the VH and VL domains (or regions) of the antibody, where these domains are present on a single polypeptide chain. Generally, scFv polypeptides further contain a polypeptide linker between the VH and VL domains, thereby enabling the scFv to form a structure desired for antigen binding.

[0163] The Fab fragment contains a variable domain and a constant domain of the light chain, and a variable domain and a first constant domain (CH1) of the heavy chain. The F(ab')2 antibody fragment generally contains a pair of Fab fragments covalently linked by a hinged cysteine ​​near the carboxyl terminus. Other chemical couplings of antibody fragments are also known in the art.

[0164] The antibodies and antibody fragments of this disclosure may be modified in the Fc region to provide a desired effector function or serum half-life. In some embodiments, the Fc region may be modified to suppress or reduce complement-dependent cytotoxicity (CDC) or antibody-dependent cytotoxicity (ADCC).

[0165] In some embodiments, multispecific antibodies are bispecific antibodies. Bispecific antibodies may be produced by manipulating the interface between a pair of antibody molecules to maximize the percentage of heterodimers recovered from recombinant cell culture. For example, the interface may contain at least a portion of the CH3 domain of the antibody constant domain. In this method, one or more small amino acid side chains from the interface of the first antibody molecule are replaced with larger side chains (e.g., tyrosine or tryptophan). Compensatory "cavities" of the same or similar size as the large side chains are created at the interface of the second antibody molecule by replacing the large amino acid side chains with smaller amino acid side chains (e.g., alanine or threonine). This provides a mechanism to increase the yield of heterodimers to outweigh other unwanted end products such as homodimers. This method is described, for example, in WO96 / 27011, which is incorporated as a whole by reference.

[0166] Any antibody or antigen-binding fragment described herein may be conjugated with a stabilizing molecule (e.g., a molecule that increases the half-life of the antibody or its antigen-binding fragment in a subject or solution). Non-limiting examples of stabilizing molecules include polymers (e.g., polyethylene glycol) or proteins (e.g., serum albumin, such as human serum albumin). Conjugation with a stabilizing molecule can increase the half-life or extend the biological activity of the antibody or antigen-binding fragment in vitro (e.g., in tissue cultures or when stored as a pharmaceutical composition) or in vivo (e.g., in the human body).

[0167] In some embodiments, the antibodies or antigen-binding fragments described herein may be conjugated to a therapeutic agent. Antibody-drug conjugates comprising an antibody or its antigen-binding fragment may be covalently or noncovalently bound to a therapeutic agent. In some embodiments, the therapeutic agent is a cytotoxic agent or a cell proliferation inhibitor (e.g., cytochalasin B, gramicidin D, ethidium bromide, emetine, mitomycin, etoposide, tenoposide, vincristine, vinblastine, colchicine, doxorubicin, daunorubicin, dihydroxyanthracine, meitansinoids such as DM-1 and DM-4, ​​dione, mitoxantrone, mitramycin, actinomycin D, 1-dehydrotestosterone, glucocorticoids, procaine, tetracaine, lidocaine, propranolol, puromycin, epirubicin, and cyclophosphamide and its analogues).

[0168] In some embodiments, the antibodies or antigen-binding fragments described herein recognize endogenous CD79b or recombinant CD79b. In some embodiments, the antibodies or antigen-binding fragments described herein recognize human CD79b (e.g., the extracellular region of human CD79b). Antibody-drug conjugates (ADCs)

[0169] The antibodies, antigen-binding fragments thereof, or antigen-binding protein constructs (e.g., bispecific antibodies) described herein can be conjugated to therapeutic agents (drugs). The therapeutic agent may be covalently or noncovalently bound to the antibody, antigen-binding fragment, or antigen-binding protein construct (e.g., bispecific antibodies).

[0170] In some embodiments, the therapeutic agent is a cytotoxic agent or a cell proliferation inhibitor (e.g., monomethyl auristatin E, monomethyl auristatin F, cytochalasin B, gramicidin D, ethidium bromide, emetine, mitomycin, etoposide, tenoposide, vincristine, vinblastine, colchicine, doxorubicin, daunorubicin, dihydroxyanthracine, meitansinoids such as DM-1 and DM-4, ​​dione, mitoxantrone, mitramycin, actinomycin D, 1-dehydrotestosterone, glucocorticoids, procaine, tetracaine, lidocaine, propranolol, puromycin, epirubicin, and cyclophosphamide and its analogues). Useful classes of cytotoxic agents, cell proliferation inhibitors, or immunomodulators include, for example, antitubulin agents, DNA sulcus binding agents, DNA replication inhibitors, and alkylating agents.

[0171] In some embodiments, the therapeutic agent may include, but is not limited to, cytotoxic reagents such as chemotherapeutic agents and immunotherapeutic agents, antiviral agents, or antibacterial agents. In some embodiments, the conjugated therapeutic agent may be selected from, but is not limited to, MMAE (monomethyl auristatin E), MMAD (monomethyl auristatin D), or MMAF (monomethyl auristatin F).

[0172] In some embodiments, the therapeutic agent is auristatin or a derivative thereof, such as auristatin E (also known in the art as a derivative of drastatin-10). Auristatin may be, for example, an ester formed between auristatin E and a keto acid. For example, auristatin E can react with paraacetylbenzoic acid or benzoylvaleric acid, respectively, to produce AEB and AEVB. Other typical auristatins include AFP, MMAF, and MMAE. Exemplary auristatin synthesis and structures are incorporated herein by reference in whole, respectively, in U.S. Patent Application Publication No. 2003-0083263, International Patent Publication No. WO04 / 010957, International Patent Publication No. WO02 / 088172, and U.S. Patent Publication Nos. 7,498,298, 6,884,869, 6,323,315, 6,239,104, 6,034,065, 5,7 Listed in issues 80,588, 5,665,860, 5,663,149, 5,635,483, 5,599,902, 5,554,725, 5,530,097, 5,521,284, 5,504,191, 5,410,024, 5,138,036, 5,076,973, 4,986,988, 4,978,744, 4,879,278, 4,816,444, and 4,486,414.

[0173] Auristatin has been shown to inhibit microtubule dynamics and nuclear and cell division, and possesses anticancer activity. Auristatin can bind to tubulin and exert cytotoxic or cell proliferation inhibitory effects on cancer cells. In the art, numerous different assays are known that can be used to determine whether auristatin or the resulting antibody-drug conjugate exerts cytotoxic or cell proliferation inhibitory effects on desired cells.

[0174] In some embodiments, the therapeutic agent is a chemotherapeutic agent. Examples of chemotherapeutic agents include alkylating agents, such as thiotepa and cyclosphosphamide (CYTOXAN®), alkyl sulfonates, such as busulfan, improsulfan and pigosulfan, aziridines, such as benzodopa, carbocone, metsuredopa and uredopa, ethyleneimines and methylamelamines, such as altretamine, triethylenemelamine, triethylenephosphoramide, triethylenethiophosphoramide and trimethylolmelamine, and nitrogenmass Drugs such as chlorambucil, chlornafadin, colophosphamide, estramustine, ifosfamide, mechloretamine, mechloretamine oxide hydrochloride, melphalan, nobenbitin, fenestrine, prednimustine, trophosphamide, uracil mustard, etc., nitrosoureas such as carmustine, chlorozotocin, fotemustine, lomustine, nimustine, ranimustine, etc., antibiotics such as acrasinomycin, actinomycin, ausramycin, azaserin, bleomycin, etc. Cutinomycin, Calicheamicin, Carabicin, Kaminomycin, Cardinophilin, Chromomycin, Dactinomycin, Daunorubicin, Detorubicin, 6-Diazo-5-Oxo-L-Norleucine, Doxorubicin, Epirubicin, Esolubicin, Idarubicin, Marcelomycin, Mitomycin, Mycophenolic acid, Nogaramycin, Olibomycin, Peplomycin, Potofilomycin, Puromycin, Keramycin, Rhodolubicin, Streptonigrin, Streptozocin, Tubercidine, Ubenimex, Dinos Tatin, zolubicin, etc., antimetabolites, e.g., methotrexate and 5-fluorouracil (5-FU), etc., folic acid analogs, e.g., denopterin, methotrexate, pteropterin, trimethrexate, etc., purine analogs, e.g., fludarabine, 6-mercaptopurine, thiamiprine, thioguanine, etc., pyrimidine analogs, e.g., ancitabine, azacitidine, 6-azauridine, carmofur, cytarabine, dideoxyuridine, doxifluridine, enocitabine, phloxuridine, 5-FU, etc., androgens, e.g., carsterone,Anti-adrenal drugs such as dromostanolone propionate, epithiostanol, mepitiostane, testolactone, etc., aminoglutethimide, mitotane, trilostane, etc., folic acid supplements such as floric acid, acegraton, aldofhomphamide glycoside, aminolevulinic acid, amsacrin, bestrabusil, bisantren, edatraxate, dehofamine, demecolsin, diazicon, elfornithine, eriptinium acetate, etogluside, gallium nitrate, hydroxyurea, lentinan, ronidamin, mitogluazone, mitoxantrone, mopidamol Nitracrine, pentostatin, fenamet, pirarubicin, podophyllic acid, 2-ethylhydrazide, procarbazine, PSK7, razoxane, schizophyllan, spirogermanium, tenuazonic acid, triadicone, 2',2',2'-trichlorotriethylamine, urethane, vindesine, dacarbazine, mannomustine, mitobronitol, mitractol, pipobromane, gasitosine, arabinoside ("Ara-C"), cyclophosphamide, taxanes, e.g., paclitaxel (TAXOL®, Bristol-Myers This includes Squibb Oncology (Princeton, NJ) and doxetaxel (TAXOTERE®, Rhone-Poulenc Rorer, Antony, France), chlorambucil, gemcitabine, 6-thioguanine, platinum analogs such as cisplatin and carboplatin, vinblastine, platinum, etoposide (VP-16), ifosfamide, mitomycin C, mitoxantrone, vincristine, vinorelbine, navelbine, novantrone, teniposide, daunomycin, aminopterin, xeloda, ibandronate, CPT-11, topoisomerase inhibitor RFS2000, difluoromethylornithine (DMFO), retinoic acid, esperamycin, capecitabine, and any pharmaceutically acceptable salts, acids, or derivatives of the above. This definition includes, for example, tamoxifen, raloxifen, aromatase inhibitor 4(5)-imidazole, 4-hydroxytamoxifen, trioxyfen, keoxyfen, LY117018, onapristone,This also includes anti-hormonal agents that act to control or inhibit the hormonal effects on tumors, such as anti-estrogen drugs including toremifene (Fareston), anti-androgen drugs such as flutamide, nilutamide, bicalutamide, leuprolide, and goserelin, and any pharmaceutically acceptable salts, acids, or derivatives of any of the above. A detailed description of chemotherapeutic agents is provided, for example, in US20180193477A1, which is incorporated as a whole by reference.

[0175] In some embodiments, the antigen-binding construct is coupled to the drug via a cleavable linker, such as an SPBD linker or a maleimidocaproyl-valine-citrulline-p-aminobenzyloxycarbonyl (VC) linker. In some embodiments, the antigen-binding construct is coupled to the drug via a non-cleavable linker, such as an MCC linker formed using SMCC or sulfo-SMCC. The selection of an appropriate linker for a given ADC can be easily made by those skilled in the art by considering relevant factors such as the attachment site to the antigen-binding construct, the structural constraints of the drug, and the hydrophobicity of the drug (see, for example, Nolting, Chapter 5, Antibody-Drug Conjugates: Methods in Molecular Biology, 2013, Ducry (Ed.), Springer review). Numerous specific linker-toxin combinations have been described and can be used in conjunction with the antigen-binding constructs described herein to prepare ADCs in certain embodiments. Examples include cleavable peptide-based linkers with auristatins such as MMAE and MMAF, SN-38, duocalmycin and camptothecin such as PBD dimers, non-cleavable MC-based linkers with auristatin MMAF and MMAE, acid-unstable hydrazone-based linkers with calicheamycin and doxorubicin, disulfide-based linkers with maytansinoids such as DM1 and DM4, and bis-maleimide-trioxyethylene glycol (BMPEO)-based linkers with maytansinoid DM1. Some of these therapeutic agents and linkers are described, for example, in Peters & Brown, (2015) Biosci. Rep. e00225, Dosio et al., (2014) Recent Patents on Anti-Cancer Drug Discovery 9:35-65, U.S. Patent Publication US2015 / 0374847, and US20180193477A1, which are incorporated herein by reference in their entirety.

[0176] Depending on the desired drug and selected linker, those skilled in the art can choose a suitable method for coupling them together. For example, several conventional coupling methods, such as amine coupling methods, can be used to form a drug-linker complex that still contains a reactive group for conjugation to an antibody via covalent bond. In some embodiments, a drug-maleimide complex (i.e., a maleimide-linked drug) can be used as the payload having the reactive group in this disclosure. The most common reactive group that can be bound to a thiol group in an ADC preparation is maleimide. In addition, organobromids and iodides are also commonly used.

[0177] ADCs can be prepared by those skilled in the art using one of several routes in the art with organic chemical reactions, conditions, and reagents (see, for example, Bioconjugate Techniques (GT Hermanson, 2013, Academic Press)). For example, conjugation can be achieved by (1) reacting the nucleophile or electrophile of the antibody with a divalent linker reagent to form an antibody-linker intermediate Ab-L via covalent bonding, and then reacting it with the activated drug moiety D, or (2) reacting the nucleophile or electrophile of the drug moiety with a linker reagent to form a drug-linker intermediate DL via covalent bonding, and then reacting it with the nucleophile or electrophile of the antibody. Conjugation methods (1) and (2) can be used to prepare the ADCs described herein using various antibodies, drug moieties, and linkers. Various prepared linkers, linker components, and toxins are commercially available or can be prepared by standard organic synthesis techniques. These methods are described, for example, in March's Advanced Organic Chemistry (Smith & March, 2006, Sixth Ed., Wiley), Toki et al., (2002) J. Org. Chem. 67:1866-1872, Frisch et al., (1997) Bioconj. Chem. 7:180-186, Bioconjugate Techniques (GT Hermanson, 2013, Academic Press), US20210379193A1, and US20180193477A1, which are incorporated herein by reference in their entirety. In addition, numerous pre-formed drug-linkers suitable for reaction with selected antigen-binding constructs are also commercially available; for example, linker-toxins containing DM1, DM4, MMAE, MMAF, or duocalmycin SA are available from Creative BioLabs (Shirley, NY).

[0178] Several specific examples of methods for preparing ADCs are known in the art and are incorporated herein by reference in U.S. Patent No. 8,624,003 (Pot Method), U.S. Patent No. 8,163,888 (One-Step Method), and U.S. Patent No. 5,208,020 (Two-Step Method), as well as U.S. 20180193477A1. Other methods are known in the art and include those described in Antibody-Drug Conjugates: Methods in Molecular Biology, 2013, Ducry (Ed.), Springer.

[0179] The drug load is expressed as the number of drug moieties per antibody in the ADC molecule. For some antibody-drug conjugates, the drug load may be limited by the number of attachment sites on the antibody. For example, if the attachment is cysteinethiol, as in certain exemplary embodiments described herein, the drug load may be 0 to 8 drug moieties per antibody. In certain embodiments, a higher drug load, e.g., p ≥ 5, may cause aggregation, insolubility, toxicity, or loss of cell permeability in certain antibody-drug conjugates. In certain embodiments, the average drug load of an antibody-drug conjugate is 1 to about 8, about 2 to about 6, or about 3 to about 5. In practice, it has been shown that for certain antibody-drug conjugates, the optimal ratio of drug moieties per antibody may be around 4. In some embodiments, the drug-antibody ratio (DAR) is about or at least 1, 2, 3, 4, 5, 6, 7, or 8. In some embodiments, the average DAR in the composition is about 1 to about 2, about 2 to about 3, about 3 to about 4, about 3 to about 5, about 4 to about 5, about 5 to about 6, about 6 to about 7, or about 7 to about 8. Antibody and ADC characteristics

[0180] The antibodies, antigen-binding fragments thereof, or ADCs derived therefrom described herein may be agonists or antagonists. In some embodiments, by binding to CD79b, the antibodies can inhibit CD79b-mediated BCR signaling.

[0181] In some embodiments, the antibody (or antigen-binding fragment thereof) or the ADC derived therefrom has a 0.1s -1 less than 0.01s -1 less than 0.001s -1 less than 0.0001s -1 less than 0.00001s -1 less than 0.000001s -1 less than or 0.0000001s -1 dissociation rate (koff) of less than and specifically binds to CD79b (e.g., human CD79b, monkey CD79b (e.g., rhesus macaque, cynomolgus monkey), canine CD79b, mouse CD79b). In some embodiments, the dissociation rate (koff) is 0.01s -1 greater than 0.001s -1 greater than 0.0001s -1 greater than 0.00001s -1 greater than 0.000001s -1 greater than 0.0000001s -1 greater than or 0.00000001s -1 greater than.

[0182] In some embodiments, the kinetic association rate (kon) is 1×10 2 / Ms greater than 1×10 3 / Ms greater than 1×10 4 / Ms greater than 1×10 5 / Ms greater than, or 1×10 6 / Ms greater than. In some embodiments, the kinetic association rate (kon) is 1×10 5 / Ms less than 1×10 6 / Ms less than, or 1×10 7 / Ms less than.

[0183] Affinity can be estimated from the quotient of the kinetic rate constant (KD=koff / kon). In some embodiments, KD is 1×10 -6 M less than 1×10 -7 M less than 1×10 -8 M less than 1×10 -9 M less than 1×10 -10 M less than 1×10 -11 M less than 1×10 -12 M less than 1×10 -13Less than M or 1 × 10 -14 It is less than M. In some embodiments, KD is 50nM, 30nM, 20nM, 15nM, 10nM, 9nM, 8nM, 7nM, 6nM, 5nM, 4nM, 3nM, 2nM, or less than 1nM. In some embodiments, KD is 1 × 10⁻¹⁶ -7 Super M, 1×10 -8 Super M, 1×10 -9 Super M, 1×10 -10 Super M, 1×10 -11 Super M, 1×10 -12 Super M, 1×10 -13 Super M, 1×10 -14 It is greater than M.

[0184] Common techniques for measuring the affinity of an antibody to an antigen include, for example, BLI, ELISA, RIA, flow cytometry, and surface plasmon resonance (SPR). In some embodiments, the antibody or its antigen-binding fragment or ADC derived therefrom described herein binds to human CD79b, monkey CD79b, canine CD79b, and / or mouse CD79b. In some embodiments, the antibody does not bind to human CD79b, monkey CD79b, canine CD79b, and / or mouse CD79b.

[0185] Furthermore, alternative splice isoforms for CD79b have been described in chronic lymphocytic leukemia. This isoform (also called the “short isoform”) encodes 125 amino acids (SEQ ID NO: 67) and differs from the 229-amino acid wild-type (also called the “long isoform”) (SEQ ID NO: 68) due to the deletion of exon 3, which essentially encodes most of the extracellular domain. In some embodiments, the anti-CD79b antibody described herein can bind to both isoforms of CD79b. In some embodiments, the anti-CD79b antibody binds to the CD79b isoform (e.g., SEQ ID NO: 67). In some embodiments, the anti-CD79b antibody does not bind to the CD79b isoform (e.g., SEQ ID NO: 67). In some embodiments, the anti-CD79b antibody binds to wild-type CD79b (e.g., SEQ ID NO: 68). In some embodiments, the antibody described herein binds to the extracellular domain of CD79b.

[0186] In some embodiments, the anti-CD79b antibody binds to a CD79b variant (e.g., SEQ ID NO: 2). In some embodiments, the anti-CD79b antibody does not bind to a CD79b variant (e.g., SEQ ID NO: 2). In some embodiments, the anti-CD79b antibody binds to an epitope located within amino acids 1-13 of the ECD of CD79b (e.g., SEQ ID NO: 1).

[0187] In some embodiments, the antibodies or antigen-binding fragments thereof or ADCs derived therefrom described herein are attached to Ramos cells to test for internalization rates. In some embodiments, at various time points (e.g., 1h, 3h, or 6h), the antibodies or antigen-binding fragments thereof or ADCs derived therefrom described herein have internalization rates of 5% or more, 10% or more, 15% or more, 20% or more, 25% or more, 30% or more, 35% or more, 40% or more, 45% or more, 50% or more, 55% or more, 60% or more, 65% or more, 70% or more, 75% or more, 80% or more, 85% or more, 90% or more, 91% or more, 92% or more, 93% or more, 94% or more, 95% or more, 96% or more, 97% or more, or 98% or more. In some embodiments, the antibodies or antigen-binding fragments thereof or ADCs derived therefrom described herein have a slower internalization rate compared to polatuzumab.

[0188] In some embodiments, thermal stability is determined. Antibodies or antigen-binding fragments thereof or ADCs derived therefrom described herein may have a Tm of 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, or greater than 95°C. In some embodiments, Tm is 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, or less than 95°C.

[0189] Since IgG can be described as a multi-domain protein, the melting curve may show two transitions at the first denaturation temperature Tm1 and the second denaturation temperature Tm2. The presence of these two peaks often indicates denaturation of the Fc domain (Tm1) and the Fab domain (Tm2), respectively. Therefore, in some embodiments, the antibody or antigen-binding fragments described herein have a Tm1 of 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, or above 95°C. In some embodiments, the antibody or antigen-binding fragment described herein has a Tm2 of 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, or greater than 95°C.

[0190] In some embodiments, Tm, Tm1, Tm2 are 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, or less than 95°C.

[0191] In some embodiments, the antibodies or antigen-binding fragments thereof or ADCs derived therefrom described herein can bind to human or monkey CD79b as measured by ELISA. In some embodiments, the antibodies or antigen-binding fragments thereof or ADCs derived therefrom described herein can bind to human or monkey CD79b with an IC50 of less than 200 nM, less than 100 nM, less than 50 nM, less than 10 nM, less than 5 nM, less than 1 nM, less than 0.75 nM, less than 0.5 nM, or less than 0.25 nM.

[0192] In some embodiments, the antibodies or antigen-binding fragments thereof, or ADCs derived therefrom, described herein, can bind to the same epitope of CD79b. In some embodiments, the antibodies or antigen-binding fragments thereof, or ADCs derived therefrom, described herein, can bind to different epitopes of CD79b.

[0193] In some embodiments, the antibodies or antigen-binding fragments thereof described herein or ADCs derived therefrom can bind to malignant B cell lines (e.g., BJAB, Ramos, Daudi, SU-DHL-4, and Nalm-6) at both high and low CD79b antigen densities, as measured by flow cytometry. In some embodiments, the EC50 is less than 200 nM, less than 100 nM, less than 50 nM, less than 10 nM, less than 5 nM, less than 1 nM, less than 0.75 nM, less than 0.5 nM, or less than 0.25 nM.

[0194] In some embodiments, the antibodies or antigen-binding fragments thereof described herein, or ADCs derived therefrom, can bind to human B cells with a higher cell surface binding affinity than polatuzumab. In some embodiments, the EC50 is less than 200 nM, less than 100 nM, less than 50 nM, less than 10 nM, less than 5 nM, less than 1 nM, less than 0.75 nM, less than 0.5 nM, or less than 0.25 nM.

[0195] In some embodiments, the antibodies described herein, their antigen-binding fragments, or ADCs derived therefrom can bind to cell surface CD79b on B lymphocytes of patients with chronic lymphocytic leukemia (CLL). In some embodiments, this binding is more potent than that of polatuzumab.

[0196] In some embodiments, the ADC described herein has a mean drug-antibody ratio (DAR) greater than 3, greater than 3.2, greater than 3.4, greater than 3.6, greater than 3.8, greater than 4, greater than 4.2, greater than 4.4, or greater than 4.6, as measured by HPLC. In some embodiments, the ADC described herein has a mean DAR less than 3, less than 3.2, less than 3.4, less than 3.6, less than 3.8, less than 4, less than 4.2, less than 4.4, or less than 4.6, as measured by HPLC. In some embodiments, the DAR is about 4.

[0197] In some embodiments, the antibodies or antigen-binding fragments thereof described herein or ADCs derived therefrom have a tumor growth inhibition percentage (TGI%) of 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 100%, 110%, 120%, 130%, 140%, 150%, 160%, 170%, 180%, 190%, or more than 200%. In some embodiments, the antibodies or antigen-binding fragments thereof described herein or ADCs derived therefrom have a tumor growth inhibition percentage of 60%, 70%, 80%, 90%, 100%, 110%, 120%, 130%, 140%, 150%, 160%, 170%, 180%, 190%, or less than 200%. TGI% can be measured, for example, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, or 30 days after the start of treatment, or 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, or 12 months after the start of treatment. As used herein, the percentage of tumor growth inhibition (TGI%) is calculated by the following formula:

number

[0198] Ti is the mean tumor volume of the treatment group on day i. T0 is the mean tumor volume of the treatment group on day 0. Vi is the mean tumor volume of the control group on day i. V0 is the mean tumor volume of the control group on day 0.

[0199] In some embodiments, the antibodies or antigen-binding fragments thereof described herein, or ADCs derived therefrom, can bind to tumor cells expressing CD79b. In some embodiments, the antibodies or antigen-binding fragments thereof described herein, or ADCs derived therefrom, can induce complement-dependent cytotoxicity (CDC) and / or antibody-dependent cytotoxicity (ADCC), thereby killing tumor cells.

[0200] In some embodiments, the antibodies or antigen-binding fragments thereof described herein or ADCs derived therefrom have a functional Fc region. In some embodiments, the effector function of the functional Fc region is antibody-dependent cell-mediated cytotoxicity (ADCC). In some embodiments, the effector function of the functional Fc region is phagocytosis. In some embodiments, the effector functions of the functional Fc region are ADCC and phagocytosis.

[0201] In some embodiments, the Fc region is human IgG1, human IgG2, human IgG3, or human IgG4. In some embodiments, the antibody is a humanized IgG1 antibody, optionally having SI mutations, LALA mutations, N297A mutations, YTE mutations, and / or FLAA mutations. In some embodiments, the antibody is a humanized IgG4 antibody, optionally having SI mutations, LALA mutations, N297A mutations, YTE mutations, and / or FLAA mutations.

[0202] In some embodiments, the antibodies or antigen-binding fragments described herein, or ADCs derived therefrom, do not have a functional Fc region. For example, the antibodies or antigen-binding fragments are Fab, Fab', F(ab')2, and Fv fragments. In some embodiments, the Fc region has LALA mutations (EU numbering L234A and L235A mutations) or LALA-PG mutations (EU numbering L234A, L235A, and P329G mutations). In some embodiments, the Fc region has FLAA mutations (EU numbering F234A and L235A). In some embodiments, Fc has SI mutations (EU numbering S239D and I332E mutations). In some embodiments, Fc has the EU numbering N297A mutation. In some embodiments, Fc has the EU numbering YTE mutations (EU numbering M252Y, S254T, and T256E). Method for producing anti-CD79b antibodies

[0203] Isolated fragments of human CD79b (e.g., the CD79b extracellular domain) can be used as immunogens to generate antibodies using standard techniques for polyclonal and monoclonal antibody preparation. Polyclonal antibodies can be produced in animals by multiple injections (e.g., subcutaneous or intraperitoneal injection) of the antigen peptide or protein. In some embodiments, the antigen peptide or protein is injected with at least one adjuvant. In some embodiments, the antigen peptide or protein can be conjugated with a drug that is immunogenic in the immunized species. Animals may be injected with the antigen peptide or protein multiple times (e.g., two, three, or four times).

[0204] A full-length polypeptide or protein (or its extracellular region) may be used as an immunogen, or a fragment of its antigen peptide may be used as an immunogen. The antigen peptide of the protein contains at least eight (e.g., at least 10, 15, 20, or 30) amino acid residues of the amino acid sequence of CD79b, encompassing the epitope of the protein, thereby allowing antibodies produced against the peptide to form a specific immune complex with the protein. As described above, the full-length sequence of human CD79b is known in the art. In some embodiments, Fc-tagged or His-tagged human CD79b protein is used as an immunogen. In some embodiments, the extracellular domain (ECD) of human CD79b is used as an immunogen.

[0205] Immunogens are typically used to prepare antibodies by immunizing a suitable target (e.g., a human or a transgenic animal expressing at least one human immunoglobulin locus). A suitable immunogenic preparation may contain, for example, a recombinant or chemically synthesized polypeptide (e.g., a fragment of human CD79b). The preparation may further contain an adjuvant such as a complete or incomplete Freund's adjuvant, or a similar immunostimulant.

[0206] Polyclonal antibodies can be prepared, as described above, by immunizing a suitable target with CD79b polypeptide or its antigenic peptide (e.g., a part of CD79b) as an immunogen. The antibody titer in the immunized target can be monitored over time using standard techniques, such as enzyme-linked immunosorbent assay (ELISA) using immobilized CD79b polypeptide or peptide. If necessary, the antibody molecule may be isolated from a mammal (e.g., from blood) and further purified by well-known techniques such as protein A or protein G chromatography to obtain an IgG fraction. At an appropriate time after immunization, for example, when the specific antibody titer is highest, antibody-producing cells can be collected from the subject and used to prepare monoclonal antibodies using standard techniques, such as the hybridoma technique first described in Kohler et al. (Nature 256:495-497, 1975), the human B-cell hybridoma technique (Kozbor et al., Immunol. Today 4:72, 1983), the EBV hybridoma technique (Cole et al., Monoclonal Antibodies and Cancer Therapy, Alan R. Liss, Inc., pp. 77-96, 1985), or the trioma technique. Techniques for producing hybridomas are well known (see, in general, Current Protocols in Immunology, 1994, Coligan et al. (Eds.), John Wiley & Sons, Inc., New York, NY). Hybridoma cells that produce monoclonal antibodies can be detected by screening the hybridoma culture supernatant for antibodies that bind to the target polypeptide or epitope, for example, using a standard ELISA assay.

[0207] Variants of antibodies or antigen-binding fragments described herein can be prepared by introducing appropriate nucleotide changes into the DNA encoding a human antibody, humanized antibody, or chimeric antibody, or its antigen-binding fragment, or by peptide synthesis. Such variants include, for example, deletions, insertions, or substitutions of residues in the amino acid sequence constituting the antigen-binding site or antigen-binding domain of the antibody. In a population of such variants, some antibodies or antigen-binding fragments exhibit increased affinity for a target protein, such as CD79b. By arbitrarily combining deletions, insertions, and / or combinations, antibodies or their antigen-binding fragments with increased binding affinity to a target can be obtained. Amino acid changes introduced into antibodies or antigen-binding fragments can also modify the antibody or antigen-binding fragment or introduce new post-translational modifications, such as changing the number of glycosylation sites (increasing or decreasing them), changing the type of glycosylation site (e.g., altering the amino acid sequence so that different sugars are attached by enzymes present in the cell), or introducing new glycosylation sites.

[0208] The antibodies disclosed herein may originate from any species of animal, including mammals. Non-limiting examples of natural antibodies include antibodies derived from humans, primates (e.g., monkeys and apes), rabbits, cattle, pigs, horses, sheep, camelids (e.g., camels and llamas), chickens, goats, and rodents (e.g., rats, mice, hamsters, and rabbits), and among them antibodies derived from transgenic animals genetically engineered to produce human antibodies.

[0209] Human and humanized antibodies include antibodies that have a variable region and a constant region derived from a human germline immunoglobulin sequence (or have the same amino acid sequence as those derived from a human germline immunoglobulin sequence). Human antibodies may include, for example, amino acid residues not encoded by a human germline immunoglobulin sequence in the CDR (e.g., mutations introduced by random or site-directed mutagenesis in vitro or by somatic mutation in vivo).

[0210] Humanized antibodies typically have a human framework (FR) into which a non-human CDR has been transplanted. Therefore, humanized antibodies have one or more amino acid sequences introduced from a non-human source. These non-human amino acid residues are often called “import” residues and are typically obtained from “import” variable domains. Humanization can be carried out essentially by substituting the corresponding sequence of a human antibody with, for example, a rodent CDR or CDR sequence. These methods are described, for example, in Jones et al., Nature, 321:522-525 (1986), Riechmann et al., Nature, 332:323-327 (1988), and Verhoeyen et al., Science, 239:1534-1536 (1988), each of which is incorporated herein by reference as a whole. Thus, a “humanized” antibody is a chimeric antibody in which a substantially intact human V domain or less has been substituted with the corresponding sequence from a non-human species. In fact, humanized antibodies are typically non-human antibodies in which several CDR residues and several FR residues are replaced with residues from similar sites in human antibodies.

[0211] The selection of human VH and VL domains used in the production of humanized antibodies is crucial for reducing immunogenicity. The V domain sequence of non-human antibodies is screened against the entire library of known human-domain sequences according to a so-called "best-fit" method. The human sequence that most closely resembles the sequence of a non-human animal is then accepted as the human FR for the humanized antibody (Sims et al., J. Immunol., 151:2296 (1993), Chothia et al., J. Mol. Biol., 196:901 (1987)).

[0212] Furthermore, it is important to humanize antibodies while maintaining high specificity and affinity for antigens, as well as other desirable biological properties. To achieve this goal, humanized antibodies may be prepared by a process of analyzing the parent sequence and various conceptual humanized products using three-dimensional models of the parent sequence and humanized sequence. Three-dimensional immunoglobulin models are generally available and well known to those skilled in the art. Computer programs are available that illustrate and display the expected three-dimensional conformational structure of selected candidate immunoglobulin sequences. By examining these displays, it is possible to analyze the possible roles of residues in the functional performance of the candidate immunoglobulin sequence, i.e., the residues that affect the candidate immunoglobulin's ability to bind to the antigen. In this way, FR residues can be selected and combined from recipient and import sequences, thereby achieving desired antibody properties such as increased affinity for the target antigen(s).

[0213] Typically, amino acid sequence variants of human, humanized, or chimeric anti-CD79b antibodies contain amino acid sequences that have at least 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% identity with the sequences present in the light or heavy chain of the original antibody.

[0214] Identity or homology to the original sequence is typically the percentage of amino acid residues present in the candidate sequence that is identical to the sequence present in the human, humanized, or chimeric anti-CD79b antibody or fragment, after the sequence has been aligned and gaps introduced as necessary to achieve the maximum possible sequence identity percentage. Any conserved substitutions are not considered part of the sequence identity.

[0215] Modifications may be added to the anti-CD79b antibody or antigen-binding fragment. For example, cysteine ​​residues may be introduced into the Fc region, thereby enabling the formation of interchain disulfide bonds in this region. Homodimerated antibodies thus produced may have an increased half-life in vitro and / or in vivo. For example, homodimerized antibodies with increased half-lives in vitro and / or in vivo can also be prepared using heterobifunctional crosslinkers, as described by Wolff et al. (Cancer Res. 53:2560-2565, 1993). Alternatively, antibodies with a double Fc region may be manipulated (see, for example, Stevenson et al., Anti-Cancer Drug Design 3:219-230, 1989).

[0216] In some embodiments, the anti-CD79b antibody or its antigen-binding fragment may be covalently modified. These covalent modifications can be carried out by chemical or enzymatic synthesis, or by enzymatic or chemical cleavage. Other types of covalent modifications of the antibody or antibody fragment are introduced into the molecule by reacting the targeted amino acid residue of the antibody or fragment with an organic derivatizing agent that can react with selected side chains or N-terminal or C-terminal residues.

[0217] In some embodiments, antibody variants are provided having a carbohydrate structure lacking fucose attached (directly or indirectly) to the Fc region. For example, the amount of fucose in such an antibody may be 1%–80%, 1%–65%, 5%–65%, or 20%–40%. The amount of fucose is determined by calculating the average amount of fucose in the glycans at Asn297 relative to the total amount of all glycostructures (e.g., complex, hybrid, and high-mannose structures) attached to Asn297 as measured by MALDI-TOF mass spectrometry, as described, for example, in WO2008 / 077546. Asn297 refers to the asparagine residue located at approximately position 297 in the Fc region (position 314 in Eu numbering or Kabat numbering of the Fc region residue). However, due to minor sequence variations within the antibody, Asn297 may also be located approximately ±3 amino acids upstream or downstream of position 297, i.e., between positions 294 and 300. Such fucosylated variants may improve ADCC function. In some embodiments, the Fc region of the antibody may be further manipulated to reduce glycan heterogeneity by replacing the asparagine at position 297 with alanine (N297A).

[0218] In some embodiments, the Fc region of the antibody was further manipulated to replace the serine at position 228 (EU numbering) of IgG4 with proline (S228P) to improve production efficiency by avoiding Fab-arm exchange. A detailed description of the S228 mutation is, for example, in Silva et al. “The S228P mutation prevents in vivo and in vitro IgG4 Fab-arm exchange as demonstrated using a combination of novel quantitative immunoassays and physiological matrix preparation.” Journal of Biological Chemistry 290.9 (2015): 5462-5469, which is incorporated as a whole by reference. Recombinant vectors

[0219] This disclosure also provides recombinant vectors (e.g., expression vectors) containing isolated polynucleotides disclosed herein (e.g., polynucleotides encoding polypeptides disclosed herein), host cells into which the recombinant vector has been introduced (i.e., host cells containing polynucleotides and / or the polynucleotide-containing vector), and products of recombinant antibody polypeptides or fragments thereof by recombinant technology.

[0220] As used herein, “vector” is any construct that can deliver one or more polynucleotides of interest to a host cell when the vector is introduced into the host cell. “Expression vector” can deliver and express one or more polynucleotides of interest as encoded polypeptides to the host cell into which the expression vector has been introduced. Thus, in an expression vector, the polynucleotide of interest is arranged to be expressed in the vector by operably ligating at or near or aside the integration site of the polynucleotide of interest with regulatory elements in the vector or host cell genome, such as promoters, enhancers and / or poly-A tails, so that the polynucleotide of interest is translated in the host cell into which the expression vector has been introduced.

[0221] Vectors can be introduced into host cells by methods known in the art, such as electroporation, chemical transfection (e.g., DEAE-dextran), transformation, transfection, infection, and / or transduction (e.g., into recombinant viruses). Therefore, non-limiting examples of vectors include viral vectors (which may be used to produce recombinant viruses), naked DNA or RNA, plasmids, cosmids, phage vectors, and DNA or RNA expression vectors that can be bound to cationic condensers.

[0222] In some implementations, the polynucleotides disclosed herein (e.g., polynucleotides encoding the polypeptides disclosed herein) may be introduced using a viral expression system (e.g., vaccinia or other poxvirus, retrovirus or adenovirus), and may also involve the use of non-pathogenic (defective) replicating competent viruses or replication-deficient viruses. In the latter case, viral transmission generally occurs only when complementing viral packaging cells. Suitable strains include, for example, Fisher-Hoch et al., 1989, Proc. Natl. Acad. Sci. USA 86:317-321, Flexner et al., 1989, Ann. NY Acad Sci. 569:86-103, Flexner et al., 1990, Vaccine, 8:17-21, U.S. Patent Nos. 4,603,112, 4,769,330, and 5,017,487, WO89 / 01973, U.S. Patent No. 4,777,127, GB2,200,651, EP0,345,242, WO91 / 02805, Berkner-Biotechniques, 6:616-627, 1988, Rosenfeld et al., 1991, Science, This is disclosed in 252:431-434, Kolls et al., 1994, Proc. Natl. Acad. Sci. USA, 91:215-219, Kass-Eisler et al., 1993, Proc. Natl. Acad. Sci. USA, 90:11498-11502, Guzman et al., 1993, Circulation, 88:2838-2848, and Guzman et al., 1993, Cir. Res., 73:1202-1207. Techniques for incorporating DNA into such expression systems are well known to those skilled in the art. For example, as described in Ulmer et al., 1993, Science, 259:1745-1749 and Cohen, 1993, Science, 259:1691-1692, DNA may be "naked." The uptake of naked DNA can be increased by coating it with biodegradable beads that are effectively transported into cells.

[0223] For expression, a DNA insert containing a polynucleotide encoding an antibody or polypeptide disclosed herein can be operably ligated to a suitable promoter (e.g., heterologous promoter), such as the phage λPL promoter, the E. coli lac, trp, and tac promoters, the SV40 early and late promoters, and the promoter of the retroviral LTR. Other suitable promoters are known to those skilled in the art. The expression construct may further contain transcription start / termination sites and ribosome binding sites for translation in the transcription region. The coding region of the mature transcript expressed by the construct may include a translation start site at the start position and a stop codon (UAA, UGA, or UAG) appropriately positioned at the end of the polypeptide being translated.

[0224] As described above, the expression vector may include at least one selection marker. Such markers include dihydrofolate reductase or neomycin resistant to eukaryotic cell culture, and tetracycline or ampicillin resistance genes for culture in Escherichia coli and other bacteria. Representative examples of suitable hosts include, but are not limited to, bacterial cells such as Escherichia coli, Streptomyces and Salmonella cells, fungal cells such as yeast cells, insect cells such as Drosophila S2 and Sphodoptera Sf9 cells, animal cells such as CHO, COS, Bowes melanoma and HK293 cells, and plant cells. Suitable media and conditions for the host cells described herein are known in the art.

[0225] Non-restrictive vectors for bacterial use include pQE70, pQE60, and pQE-9 available from Qiagen; pBS vector, Phagescript vector, Bluescript vector, pNH8A, pNH16a, pNH18A, and pNH46A available from Stratagene; and ptrc99a, pKK223-3, pKK233-3, pDR540, and pRIT5 available from Pharmacia. Non-restrictive eukaryotic vectors include pWLNEO, pSV2CAT, pOG44, pXT1, and pSG available from Stratagene; and pSVK3, pBPV, pMSG, and pSVL available from Pharmacia. Other suitable vectors are readily apparent to those skilled in the art.

[0226] Suitable non-limiting bacterial promoters include the E. coli lacI and lacZ promoters, T3 and T7 promoters, gpt promoter, λ PR and PL promoters, and trp promoter. Suitable eukaryotic promoters include the CMV early promoter, HSV thymidine kinase promoter, SV40 early and late promoters, retroviral LTR promoters (e.g., the Roussarcoma virus (RSV) promoter), and metallothionein promoters (e.g., the mouse metallothionein-I promoter).

[0227] In brewing yeast, numerous vectors containing constitutive or inductive promoters, such as α-factor, alcohol oxidase, and PGH, can be used. For reviews, see Ausubel et al. (1989) Current Protocols in Molecular Biology, John Wiley & Sons, New York, NY, and Grant et al., Methods Enzymol., 153: 516-544 (1997).

[0228] The introduction of constructs into host cells can be achieved by calcium phosphate transfection, DEAE-dextran-mediated transfection, cationic lipid-mediated transfection, electroporation, transduction, infection, or other methods. Such methods are described in many standard laboratory manuals, such as Davis et al., Basic Methods In Molecular Biology (1986), which is incorporated herein by reference in whole.

[0229] By inserting enhancer sequences into vectors, the transcription of DNA encoding the antibodies relating to this disclosure can be increased in higher eukaryotes. Enhancers are cis-elements of DNA, typically about 10–300 bp in length, and function to enhance the transcriptional activity of a promoter in a given host cell type. Examples of enhancers include SV40 enhancers located after the replication origin at base pairs 100–270, cytomegalovirus early promoter enhancers, polyoma enhancers located after the replication origin, and adenovirus enhancers.

[0230] Suitable secretory signals can be incorporated into expressed polypeptides to secrete translated proteins into the lumen of the endoplasmic reticulum, the pericellular lumen, or the extracellular environment. These signals may be endogenous or heterologous to the polypeptide.

[0231] Polypeptides (e.g., antibodies) may be expressed in modified forms, such as fusion proteins (e.g., GST-fusions) or forms with histidine tags, and may include not only secretory signals but also additional heterologous functional regions. For example, adding additional amino acids, particularly charged amino acid regions, to the N-terminus of a polypeptide can improve its stability and persistence during purification, subsequent handling, and storage in host cells. Peptide moieties can also be added to polypeptides for easier purification. Such regions may be removed before the final preparation of the polypeptide. Adding peptide moieties to polypeptides to induce secretion or excretion, improve stability, or facilitate purification is a well-known and common technique in the art. Treatment method

[0232] The antibodies or antigen-binding fragments thereof disclosed herein can be used for a variety of therapeutic purposes.

[0233] In one embodiment, the disclosure provides a method for treating a target cancer, a method for slowing the rate of growth of a target tumor over time, a method for reducing the risk of metastasis, or a method for reducing the risk of further metastasis to the target. In some embodiments, the treatment can halt, regress, delay, or inhibit the progression of the cancer. In some embodiments, the treatment can result in a reduction in the number, severity, and / or duration of one or more symptoms of the target cancer.

[0234] In one embodiment, the Disclosure features a method comprising administering a therapeutically effective amount of the antibody or antigen-binding fragment thereof disclosed herein to a subject in need (e.g., a subject having cancer, or a subject identified or diagnosed with cancer), such cancer being, for example, breast cancer (e.g., trine-negative breast cancer), carcinoid cancer, cervical cancer, endometrial cancer, glioma, head and neck cancer, liver cancer, lung cancer, small cell lung cancer, lymphoma, melanoma, ovarian cancer, pancreatic cancer, prostate cancer, kidney cancer, colorectal cancer, gastric cancer, testicular cancer, thyroid cancer, bladder cancer, urethral cancer, or hematological malignancies. In some embodiments, the cancer is unresectable or metastatic melanoma, non-small cell lung cancer (NSCLC), small cell lung cancer (SCLC), bladder cancer, or metastatic hormone-refractory prostate cancer. In some embodiments, the cancer is NSCLC, ovarian cancer, melanoma, colorectal cancer, breast cancer, hematological malignancies, head and neck cancer, gastrointestinal cancer, bladder cancer, or bone cancer. In some embodiments, the subjects have Hodgkin lymphoma. In some embodiments, the subjects have trinegative breast cancer (TNBC), gastric cancer, urothelial carcinoma, Merkel cell carcinoma, or head and neck cancer. In some embodiments, the cancer is melanoma, pancreatic cancer, mesothelioma, hematological malignancies, particularly non-Hodgkin lymphoma, lymphoma, chronic lymphocytic leukemia, or progressive solid tumors. In some embodiments, the cancer is lymphoma, breast cancer, gastric cancer, pancreatic cancer, prostate cancer, cervical cancer, endometrial cancer, ovarian cancer, or urothelial carcinoma.

[0235] In one embodiment, the present disclosure provides a method for treating a subject having an autoimmune disease, the method comprising administering a therapeutically effective amount of a composition comprising an antibody or its antigen-binding fragment, CAR, or antibody-drug conjugate as described herein to the subject.

[0236] In some embodiments, the autoimmune disease is selected from rheumatoid arthritis, psoriasis, multiple sclerosis, immune thrombocytopenic purpura, myasthenia gravis, neuromyelitis optica, IgG4-related disease, systemic lupus erythematosus, lupus nephritis, giant cell arteritis, Takayasu's arteritis, cold agglutinin disease, warm autoimmune hemolytic anemia, and anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis, such as granulomatosis with polyangiitis (GPA) (Wegener's granulomatosis) or microscopic polyangiitis (MPA).

[0237] In some embodiments, the autoimmune disease is multiple sclerosis, systemic lupus erythematosus, or rheumatoid arthritis.

[0238] In some embodiments, the compositions and methods disclosed herein can be used to treat patients at risk of cancer. Cancer patients can be identified by various methods known in the art.

[0239] In one embodiment, the present disclosure provides methods for treating, preventing, or reducing the risk of developing disorders associated with abnormal or unwanted immune responses, such as autoimmune disorders. These autoimmune disorders include alopecia areata, lupus, ankylosing spondylitis, Meniere's disease, antiphospholipid syndrome, mixed connective tissue disease, autoimmune Addison's disease, multiple sclerosis, autoimmune hemolytic anemia, myasthenia gravis, autoimmune hepatitis, pemphigus vulgaris, Behçet's disease, pernicious anemia, bullous pemphigoid, polyarteritis nodosa, cardiomyopathy, polychondritis, celiac plue dermatitis, polyglandular syndrome, chronic fatigue syndrome (CFIDS), polymyalgia rheumatica, chronic inflammatory demyelination, polymyositis and dermatomyositis, chronic inflammatory polyneuropathy, primary agammaglobulinemia, Churg-Strauss syndrome, and This includes, but is not limited to, biliary cirrhosis, pemphigoid scarring, psoriasis, CREST syndrome, Raynaud's phenomenon, cold agglutinin disease, Reiter's syndrome, Crohn's disease, rheumatic fever, lupus discoid, rheumatoid arthritis, cryoglobulinemia, sarcoidosis, fibromyalgia, scleroderma, Graves' disease, Sjögren's syndrome, Guillain-Barré syndrome, generalized rigidity syndrome, Hashimoto's thyroiditis, Takayasu's arteritis, idiopathic pulmonary fibrosis, temporal arteritis / giant cell arteritis, idiopathic thrombocytopenic purpura (ITP), ulcerative colitis, IgA nephropathy, uveitis, diabetes mellitus (e.g., type 1), vasculitis, lichen planus, and vitiligo. Anti-CD79b antibodies or their antigen-binding fragments may be administered to a subject to treat, prevent, or reduce the risk of developing graft-versus-host disease (GVHD), or to prevent allograft rejection, in cases of abnormal or unwanted immune responses associated with cell, tissue, or organ transplantation, such as kidney, liver, and heart transplantation. In some embodiments, the subject has a dermatological disorder, liver disease (e.g., cirrhosis), hidradenitis, or experimental autoimmune encephalomyelitis. In some embodiments, the subject has a renal disorder, lupus, Sjögren's syndrome, ulcerative colitis, psoriasis, hidradenitis suppurativa, immune thrombocytopenia (ITP), or other inflammatory arthritis. In some embodiments, the subject has multiple sclerosis or myasthenia gravis. In some embodiments, the subject has Crohn's disease, ulcerative colitis, or type 1 diabetes.In some embodiments, the subject has autoimmune thyroid disease, Graves' disease, multiple sclerosis, psoriasis, inflammatory bowel disease (e.g., Crohn's disease (CD) and ulcerative colitis), rheumatoid arthritis, Sjögren's syndrome, autoimmune nephritis, or systemic lupus erythematosus. In some embodiments, the method comprises administering to the subject an effective amount of a composition comprising an antibody or an antigen-binding fragment thereof described herein.

[0240] As used herein, an "effective amount" means an amount or dose sufficient to bring about a beneficial or desired result, including stopping, regressing, delaying or inhibiting the progression of a disease, for example, an autoimmune disease or cancer. An effective amount can vary depending on, for example, the age and body weight of the subject to whom the antibody, antigen-binding fragment, antibody-encoding polynucleotide, vector comprising the polynucleotide, and / or composition thereof is administered, the severity of symptoms and the route of administration, and therefore administration may be determined individually.

[0241] An effective amount can be administered in a single dose or in multiple doses. By way of example, an effective amount of an antibody or antigen-binding fragment is an amount sufficient to ameliorate, stop, stabilize, reverse, inhibit, regress and / or delay the progression of an autoimmune disease or cancer in a patient, or is sufficient to ameliorate, stop, stabilize, reverse, regress and / or delay the proliferation of cells in vitro (e.g., biopsy cells, any of the cancer cells described herein, or a cell line (e.g., a cancer cell line)). As understood in the art, an effective amount of an antibody or antigen-binding fragment can vary depending on other factors, particularly including the patient's medical history and the type (and / or dose) of the antibody used.

[0242] The effective doses and schedules for administering the antibodies, antibody-coded polynucleotides, and / or compositions disclosed herein may be determined empirically, and making such determinations is within the scope of the skills of the art. Those skilled in the art will understand that the dose to be administered will vary depending, for example, on the mammal to which the antibodies, antibody-coded polynucleotides, and / or compositions disclosed herein are administered, on the route of administration, on the specific type of antibody, antibody-coded polynucleotide, antigen-binding fragment, and / or composition used herein, and on other drugs administered to the mammal. Guidance for selecting an appropriate dose of antibody or antigen-binding fragment is found in the literature on the therapeutic use of antibodies and antigen-binding fragments, for example, Handbook of Monoclonal Antibodies, Ferrone et al., eds., Noges Publications, Park Ridge, NJ, 1985, ch. 22 and pp. 303-357, and Smith et al., Antibodies in Human Diagnosis and Therapy, Haber et al., eds., Raven Press, New York, 1977, pp. 365-389.

[0243] A typical daily effective dose of antibody is 0.01 mg / kg to 100 mg / kg. In some embodiments, the dose may be 100 mg / kg, 10 mg / kg, 9 mg / kg, 8 mg / kg, 7 mg / kg, 6 mg / kg, 5 mg / kg, 4 mg / kg, 3 mg / kg, 2 mg / kg, 1 mg / kg, 0.5 mg / kg, or less than 0.1 mg / kg. In some embodiments, the dose may be 10 mg / kg, 9 mg / kg, 8 mg / kg, 7 mg / kg, 6 mg / kg, 5 mg / kg, 4 mg / kg, 3 mg / kg, 2 mg / kg, 1 mg / kg, 0.5 mg / kg, 0.1 mg / kg, 0.05 mg / kg, or greater than 0.01 mg / kg. In some embodiments, the dose is approximately 10 mg / kg, 9 mg / kg, 8 mg / kg, 7 mg / kg, 6 mg / kg, 5 mg / kg, 4 mg / kg, 3 mg / kg, 2 mg / kg, 1 mg / kg, 0.9 mg / kg, 0.8 mg / kg, 0.7 mg / kg, 0.6 mg / kg, 0.5 mg / kg, 0.4 mg / kg, 0.3 mg / kg, 0.2 mg / kg, or 0.1 mg / kg.

[0244] In any of the methods described herein, at least one antibody, an antigen-binding fragment thereof, or a pharmaceutical composition (e.g., any of the antibodies, antigen-binding fragments, or pharmaceutical compositions described herein), and optionally at least one additional therapeutic agent, may be administered to a subject at least once a week (e.g., once a week, twice a week, three times a week, four times a week, once a day, twice a day, or three times a day). In some embodiments, at least two different antibodies and / or antigen-binding fragments are administered in the same composition (e.g., a liquid composition). In some embodiments, at least one antibody or antigen-binding fragment and at least one additional therapeutic agent are administered in the same composition (e.g., a liquid composition). In some embodiments, at least one antibody or antigen-binding fragment and at least one additional therapeutic agent are administered in two different compositions (e.g., a liquid composition comprising at least one antibody or antigen-binding fragment and an oral solid composition comprising at least one additional therapeutic agent). In some embodiments, at least one additional therapeutic agent is administered as a pill, a tablet, or a capsule. In some embodiments, at least one additional therapeutic agent is administered in a sustained-release oral formulation.

[0245] In some embodiments, one or more additional therapeutic agents may be administered to the subject before or after administration of at least one antibody, an antigen-binding antibody fragment, or a pharmaceutical composition (e.g., any of the antibodies, antigen-binding antibody fragments, or pharmaceutical compositions described herein). In some embodiments, one or more additional therapeutic agents and at least one antibody, an antigen-binding antibody fragment, or a pharmaceutical composition (e.g., any of the antibodies, antigen-binding antibody fragments, or pharmaceutical compositions described herein) are administered to the subject such that the periods of biological activity of the one or more additional therapeutic agents and the at least one antibody or antigen-binding fragment (e.g., the antibody or antigen-binding fragment described herein) overlap in the subject.

[0246] In some embodiments, a subject may be administered at least one antibody, antigen-binding antibody fragment, or pharmaceutical composition (e.g., any of the antibodies, antigen-binding antibody fragments, or pharmaceutical compositions described herein) over a long period of time (e.g., at least one week, two weeks, three weeks, one month, two months, three months, four months, five months, six months, seven months, eight months, nine months, ten months, eleven months, twelve months, one year, two years, three years, four years, or five years). A skilled medical professional may determine the length of the treatment period using any of the methods for diagnosing or tracking the effectiveness of the treatment described herein (e.g., observing at least one symptom of cancer). As described herein, skilled medical professionals may, based on an assessment of the effectiveness of the treatment (for example, using any of the methods described herein and known in the art), modify the identity and number (e.g., increase or decrease) of the antibodies or antigen-binding antibody fragments (and / or one or more additional therapeutic agents) administered to the subject, and adjust (e.g., increase or decrease) the dose or frequency of administration of at least one antibody or antigen-binding antibody fragment (and / or one or more additional therapeutic agents) to the subject.

[0247] In some embodiments, one or more additional therapeutic agents may be administered. The additional therapeutic agents may include one or more inhibitors selected from the group consisting of B-Raf inhibitors, EGFR inhibitors, MEK inhibitors, ERK inhibitors, K-Ras inhibitors, c-Met inhibitors, anaplastic lymphoma kinase (ALK) inhibitors, phosphatidylinositol 3-kinase (PI3K) inhibitors, Akt inhibitors, mTOR inhibitors, dual PI3K / mTOR inhibitors, Bruton's tyrosine kinase (BTK) inhibitors, and isocitrate dehydrogenase 1 (IDH1) and / or isocitrate dehydrogenase 2 (IDH2) inhibitors. In some embodiments, the additional therapeutic agent is an indoleamine 2,3-dioxygenase-1 (IDO1) inhibitor (e.g., epacadostat).

[0248] In some embodiments, additional therapeutic agents may include one or more inhibitors selected from the group consisting of PD-1 inhibitors, LSD1 inhibitors, MDM2 inhibitors, BCL2 inhibitors, CHK1 inhibitors, activated Hedgehog signaling pathway inhibitors, and agents that selectively degrade estrogen receptors.

[0249] In some embodiments, additional therapeutic agents include trabectedin, nab-paclitaxel, trevananib, pazopanib, cedilanib, palbociclib, everolimus, fluoropyrimidine, IFL, regorafenib, reolisin, alimta, zykadia, sutent, temsirolimus, axitinib, everolimus, sorafenib, votrient, pazopanib, IMA-901, and AGS-003. The therapeutic agent may include one or more therapeutic agents selected from the group consisting of cabozantinib, vinflunin, Hsp90 inhibitors, Ad-GM-CSF, temazolomide, IL-2, IFNa, vinblastine, salomib, dacarbazine, cyclophosphamide, lenalidomide, azacitidine, lenalidomide, bortezomid, amrubicin, carfilzomib, pralatrexate, and enzastaurin.

[0250] In some embodiments, additional therapeutic agents may include one or more therapeutic agents selected from the group consisting of adjuvants, TLR agonists, tumor necrosis factor (TNF)α, IL-1, HMGB1, IL-10 antagonists, IL-4 antagonists, IL-13 antagonists, IL-17 antagonists, HVEM antagonists, ICOS agonists, therapeutic targets CX3CL1, CXCL9, CXCL10, CCL5, LFA-1 agonists, ICAM1 agonists, and PD-1 agonists.

[0251] In some embodiments, carboplatin, nab-paclitaxel, paclitaxel, cisplatin, pemetrexed, gemcitabine, FOLFOX, or FOLFIRI are administered to the target patient.

[0252] In some embodiments, additional therapeutic agents include anti-OX40 antibody, anti-PD-1 antibody, anti-PD-L2 antibody, anti-LAG-3 antibody, anti-TIGIT antibody, anti-BTLA antibody, anti-CTLA4 antibody, anti-ICOS antibody, anti-CD27 antibody, anti-4-1BB antibody, anti-CD40 antibody, anti-VEGFR2 antibody, anti-EGFR antibody, anti-HER2 antibody, TIM3 antibody, CD103 antibody, TGFBR2 antibody, and / or anti-GITR antibody.

[0253] In one embodiment, the present disclosure provides a combination therapy. In some embodiments, an anti-CD79b antibody or its antigen-binding fragment (e.g., any antibody described herein) may be administered together with an anti-CTLA4 antibody. Pharmaceutical composition and route of administration

[0254] This specification also provides pharmaceutical compositions containing at least one (e.g., one, two, three, or four) of the antibodies or antigen-binding fragments described herein. Two or more (e.g., two, three, or four) of any of the antibodies or antigen-binding fragments described herein may be present in any combination in the pharmaceutical composition. The pharmaceutical composition can be formulated in any manner known in the art.

[0255] The pharmaceutical composition is formulated to match the intended route of administration (e.g., intravenous, intra-arterial, intramuscular, intradermal, subcutaneous, or intraperitoneal). The composition may contain sterile diluents (e.g., sterile water or saline), non-volatile oils, polyethylene glycol, glycerin, propylene glycol, or other synthetic solvents, antimicrobial or antifungal agents (e.g., benzyl alcohol or methylparaben, chlorobutanol, phenol, ascorbic acid, thimerosal, etc.), antioxidants (e.g., ascorbic acid or sodium bisulfite, etc.), chelating agents (e.g., ethylenediaminetetraacetic acid, etc.), buffers (e.g., acetates, citrates, or phosphates, etc.), and isotonic agents (e.g., sugars (e.g., dextrose), polyhydric alcohols (e.g., mannitol or sorbitol) or salts (e.g., sodium chloride), etc.), or any combination thereof. The liposome suspension can also be used as a pharmaceutically acceptable carrier (see, for example, U.S. Patent No. 4,522,811). The composition can be formulated and encapsulated in ampoules, disposable syringes, or multi-dose vials. Appropriate fluidity can be maintained, if necessary (e.g., in injectable formulations), by using coatings such as lecithin or surfactants. Absorption of antibodies or their antigen-binding fragments can be extended by including absorption-delaying agents (e.g., aluminum monostearate and gelatin). Alternatively, controlled release can be achieved by implants and microencapsulation delivery systems that may contain biodegradable, biocompatible polymers (e.g., ethylene vinyl acetate, polyacid anhydride, polyglycolic acid, collagen, polyorthoesters, and polylactic acid, as provided by Alza Corporation and Nova Pharmaceutical, Inc.).

[0256] Compositions containing one or more antibodies or antigen-binding fragments described herein can be formulated in unit dosage forms (i.e., physical dispersion units containing a predetermined amount of the active compound for easier administration and dose uniformity) for parenteral administration (e.g., intravenous, intra-arterial, intramuscular, intradermal, subcutaneous, or intraperitoneal).

[0257] Pharmaceutical compositions for parenteral administration are preferably sterile, substantially isotonic, and manufactured under Good Manufacturing Practice (GMP) conditions. The pharmaceutical compositions can be provided in unit dosage forms (i.e., single doses). The pharmaceutical compositions can be formulated using one or more physiologically acceptable carriers, diluents, excipients, or auxiliaries. The formulation varies depending on the chosen route of administration. For injection, the antibody can be formulated in an aqueous solution, preferably a physiologically compatible buffer, to reduce injection site discomfort. The solution may contain formulation agents such as suspending agents, stabilizers, and / or dispersants. Alternatively, the antibody may be lyophilized before use for use with a suitable vehicle, such as sterile water free of pyrogens.

[0258] The toxicity and therapeutic efficacy of a composition can be determined by standard pharmaceutical procedures in cell cultures or experimental animals (e.g., monkeys). For example, the LD50 (lethal dose in 50% of the population) and ED50 (therapeutably effective dose in 50% of the population) can be determined. The therapeutic index is the ratio of LD50:ED50. Drugs exhibiting a high therapeutic index are preferred. If a drug exhibits undesirable side effects, care must be taken to minimize potential harm (i.e., reduce unwanted side effects). Toxicity and therapeutic efficacy may also be determined by other standard pharmaceutical procedures.

[0259] Data obtained from cell culture assays and animal studies can be used to formulate appropriate doses of any prescribed agent for use in a subject (e.g., human). The therapeutically effective dose of one or more (e.g., one, two, three, or four) antibodies or their antigen-binding fragments (e.g., any of the antibodies or antibody fragments described herein) is the amount that treats the disease in a subject (e.g., a human subject identified as having cancer) or a subject identified as being at risk of developing the disease (e.g., a subject who previously had cancer but is now cured) and reduces the severity, frequency, and / or duration of one or more symptoms of the disease in the subject (e.g., human). The efficacy and dose of any antibody or antigen-binding fragment described herein can be determined by a medical or veterinary expert using methods known in the art and observing one or more symptoms of the disease in a subject (e.g., human). Several factors may influence the dosage and timing required to effectively treat the subject (e.g., severity of the disease or disability, previous treatment, the subject's general health and / or age, and the presence of other medical conditions).

[0260] Exemplary doses include milligrams or micrograms of any antibody or antigen-binding fragment described herein per kilogram of body weight of the subject (e.g., about 1 μg / kg to about 500 mg / kg, about 100 μg / kg to about 500 mg / kg, about 100 μg / kg to about 50 mg / kg, about 10 μg / kg to about 5 mg / kg, about 10 μg / kg to about 0.5 mg / kg, or about 1 μg / kg to about 50 μg / kg). While these doses cover a wide range, those skilled in the art will understand that therapeutic agents containing antibodies and their antigen-binding fragments have varying potencies, and that effective doses can be determined by methods known in the art. Typically, a relatively low dose is administered initially, and the responsible medical or veterinary professional (for therapeutic use) or researcher (if still in development) may gradually increase the dose until an appropriate response is obtained. Furthermore, it is understood that the specific dose level for a particular target depends on various factors such as the activity of the specific compound used, the target's age, weight, overall health status, sex, diet, administration time, route of administration, excretion rate, and the in vivo half-life of the antibody or antibody fragment.

[0261] The pharmaceutical composition may be contained in a container, pack, or dispenser along with instructions for administration. This disclosure also provides methods for producing antibodies or their antigen-binding fragments for the various uses described herein. [Examples]

[0262] The present invention will be further described in the following embodiments, but these will not limit the scope of the present invention as described in the claims.

[0263] Example 1: Production of anti-CD79b antibody Rabbit immunization with CD79b antigen To generate monoclonal antibodies against human CD79b, two New Zealand white rabbits were immunized with human CD79b ECD antigen (SEQ ID NO: 1, amino acids 29-159, his tagged, manufactured by AcroBiosystems) using either complete or incomplete Freund's adjuvant. Serum titers were monitored by ELISA after the second injection.

[0264] Screening of single B cells producing monoclonal antibodies against CD79b After immunizing 3 to 4 times at 200 μg per injection per rabbit, a final booster injection was administered to rabbits with a good titer (>1:100,000), and the spleen was collected 7 days after the final injection.

[0265] Isolation of spleen cells from rabbits All the following procedures (except centrifugation) were performed in a biological safety cabinet. Rabbit spleens were collected 7 days after the final booster injection. Spleen cells were prepared with a sterile cell strainer placed on the bottom of a 100 mm sterile petri dish containing 20 mL of RPMI + 1% penicillin-streptomycin (P / S). Using sterile forceps, the spleen tissue was transferred to the cell strainer. Specifically, while holding the spleen with forceps, it was cut into small pieces, and then pushed through the mesh of the cell strainer. The tissue fragments were washed with 10 mL of RPMI + 1% P / S. The spleen cells were transferred from the petri dish to a new 50 mL conical tube. RPMI + 1% P / S was added to a final volume of 50 mL. The cells were centrifuged at 400 × g for 5 min, and the supernatant was aspirated. 13 mL of ACK buffer (Gibco cat# A1049201) was added to resuspend the cells. The resuspended cells were incubated at room temperature for 1 minute. RPMI + 1% P / S was added to a final volume of 50 mL. The cells were centrifuged at 400 × g for 5 min, and the supernatant was aspirated. The cell pellet was resuspended in RPMI + 10% FBS + 1% P / S. The cells were centrifuged at 400 × g for 5 min, and the supernatant was aspirated. The pellet was resuspended in 15 mL of RPMI + 10% FBS + 1% P / S. Cells were pipetted through a 100 μm cell strainer into a 50 mL conical tube to remove cell clumps. Next, spleen cells were inoculated into an appropriate medium at a desired density (e.g., 4E6 cells / ml) and aliquoted. The remaining spleen cells were resuspended in 90% serum + 10% DMSO at 6×10 7 cells / vial (approximately 1.8 mL) and frozen overnight at -80°C. The frozen cells were transferred to a liquid nitrogen tank for long-term storage.

[0266] Antigen-specific B cell sorting For B cell preparation, newly isolated or thawed spleen cells (approximately 2 × 10⁻¹⁰) 8 Spleen cells were cultured overnight in B cell culture medium (RPMI-1640, 15% FBS, 1× HEPES, 1× 2-ME (2-mercaptoethanol), 1% penicillin / streptomycin) before sorting. Accordingly, 96-well B cell supply plates were prepared one day before sorting. On the day of sorting, loosely attached suspended spleen cells were collected by gently pipetting the medium onto the culture surface of the flask. The cells were then transferred to a conical tube and centrifuged at 400×g for 3 minutes. The cell pellet was washed twice with fluorescence-activated cell sorting (FACS) buffer (1× PBS + 0.5% BSA). Biotinylated antigen was added at 5 μg / ml (final concentration). The mixture was incubated at room temperature (RT) for 20 minutes. The stained mixture was then centrifuged at 400×g for 3 minutes, and the cells were resuspended in FACS buffer. The cells were transferred to a 1.5 ml amber Eppendorf tube. Next, the staining antibody mixture was added to the cells. The staining mixture was incubated at 4°C for 15-30 minutes, and then centrifuged at 400×g for 3 minutes. The cell pellet was washed twice with FACS buffer. The washed cell pellet was hydrated in 1×PBS + 1% FBS for approximately 10 minutes. 7 The cells were resuspended at a concentration of cells / ml. Antigen-specific single B cells were isolated into 96-well plates (20 plates per rabbit) using fluorescence-activated cell sorting. The 96-well B cell culture plates containing the isolated B cells were cultured at 37°C in 5% CO2 for 12 days.

[0267] Screening of single B cell cultures Eight days after sorting, 15 μL of B cell culture supernatant was collected from each well for antigen-specific ELISA. In short, the B cell culture supernatant was transferred to a 384-well plate coated with the extracellular domain (ECD) of CD79b and then blocked. Cells were incubated at room temperature for 1 hour and washed three times with PBS + 0.05% Tween-20. Secreted antibodies were detected with goat anti-rabbit IgG HRP + TMB substrate. Next, B cell supernatants meeting the cutoff OD450 (>0.5 or 3 times higher than preimmune serum) were selected. Using FACS, the selected cells were screened for (1) N-terminal deletion CD79b variant (deletion of the first 13 amino acid residues from the N-terminus, SEQ ID NO: 2), (2) interspecies binding against cynomolgus monkey CD79b (SEQ ID NO: 3), and (3) cell surface binding against Daudi cells.

[0268] Initial ELISA screening of the supernatant from B cells isolated onto 40 plates (96-well plates) was performed for CD79b-specific antibodies. Approximately 230 CD79b antigen-specific positive B cell clones were identified.

[0269] Twelve days after sorting, the B cell culture plates were centrifuged at 400×g for 3 minutes. The supernatant was collected from positive clones (those with an OD exceeding the cutoff selected from the antigen-specific ELISA), and the cell pellet was stored in a 100 μL DNA / RNA shield (Zymo Cat# R1100-250) in a 250 μL PCR tube. The collected supernatant was subjected to additional tests as described below.

[0270] Screening of CD79b-specific antibodies that bind to cell surface-expressed CD79b. CD79b is a member of the B cell receptor complex. Due to epitope accessibility, it is expected that not all antibody clones that bind to CD79b in ELISA will also bind to cell surface-expressed CD79b. CD79b-specific B cell clones identified by ELISA were subjected to a cell surface binding assay with Daudi cells by FACS. In short, 50 μl of B cell supernatant (diluted 1:10 with FACS buffer, 1×PBS + 0.5% BSA) was incubated with 50,000 Daudi cells (plated in a 96-well plate) on ice for 1 hour and washed twice with 150 μl of ice-cold FACS buffer. 100 μl of anti-rabbit-PE secondary antibody (Biolegend) was added, mixed, and incubated on ice for 30 minutes. The cells were washed three times with 150 μl of FACS buffer and finally resuspended in 100 μl of FACS buffer. 5,000 cells were collected from each stain using a flow cytometer for analysis. Of approximately 230 ELISA-positive B cell clones, 12 clones were shown to bind to CD79b on the cell surface.

[0271] Recovery of VH and VL gene sequences from selected anti-CD79b clones DNA fragments encoding the heavy chain variable domain (VH) and light chain variable domain (VL) from B cell clones that exhibit high cell surface binding affinity to CD79b were amplified by 5'RACE (rapid amplification of cDNA ends), cloned using TOPO, and sequenced.

[0272] Example 2: Generation of Chimeric Expression Constructs To express a rabbit / human chimeric IgG1 antibody, the heavy chain constant region of human IgG1 (CH1~CH3, SEQ ID NO: 4) and the human kappa light chain constant region (CL-Kappa, SEQ ID NO: 5) were synthesized and cloned into the pcDNA3.4 vector (Invitrogen). The heavy chain cloning vector pcDNA3.4-huIgG1-Hc was digested with EcoRI / NheI for cloning of the VH fragment. The light chain cloning vector pcDNA3.4-huKappa-Lc was digested with EcoRI / BsiWI for cloning of the VL fragment. Recombinant rabbit / human chimeric antibody constructs were generated. Specifically, VH and VL sequences (Figure 22) selected from rabbit anti-CD79b antibody were obtained by gene synthesis (Integrated DNA technology), ligated to a secretion leader sequence (SEQ ID NO: 6) having duplicate sequences at both the 5' and 3' ends, and Gibson assembly (NEB NEBuilder® HiFi DNA Assembly) was performed to generate HC and LC expression plasmids. Competent E. coli (NEB® 5-alpha) were transformed using the assembled plasmids. Clones with the correct sequences were selected based on sequencing results (Elim Biopharm) and further cultured in LB containing carbenicillin (100 ug / ml). The plasmids were purified (QIAGEN Plasmid Plus Kits), eluted with nuclease-free H2O (Sigma), and stored at -80°C.

[0273] Example 3 Expression and purification of chimeric anti-CD79b antibody Recombinant chimeric antibodies were expressed in CHO cells (ExpiCHO® Expression System, Gibco) by transfecting them with pcDNA3.4-huIgG1-Hc and pcDNA3.4-huKappa-Lc containing paired VH and VL sequences. ExpiCHO cells were cultured in ExpiCHO expression medium, and the cells were expressed at a rate of 0.3-6 × 10⁶. 6Cells / ml were maintained at 37°C, 125 rpm, 5% CO2, and 80% humidity. 25 ml of fresh ExpiCHO cells (6 × 10⁶) were placed in a 125 ml baffled flask. 6 ( / ml, survival rate >95%, prepared the day before transfection) 3 × 10 6 Seeds were seeded at / ml. 1 ml of serum-free medium (OptiPRO® SFM, Gibco) containing pcDNA3.4-huIgG1-Hc and pcDNA3.4-huKappa-Lc (12 ug each plasmid) was thoroughly mixed by pipetting with 1 ml of OptiPRO® SFM containing 80 ul of transfection reagent (ExpiFectamine® CHO Reagent, Gibco). Next, the transfection mixture was added to 25 ml of ExpiCHO cells and cultured at 37°C. The following day, 150 ul of ExpiFectamine® CHO Enhancer, 6 ml of ExpiCHO® Feed, and 1X penicillin-streptomycin (Gibco) were added, and the transfection cultures were transferred to a 32°C incubator. Cell density and viability of transfection cultures were monitored, and IgG1 antibody titers in the culture medium were monitored using a biolayer interference (BLI) instrument equipped with a protein A biosensor (Gator Prime from Gator Bio).

[0274] After 5 days, the culture medium containing the secreted IgG1 antibody was collected (centrifuged at 2000g for 10 minutes), filtered (Thermo Scientific® Nalgene® Rapid-Flow® Sterile Disposable Filter), and further purified using a gravity flow column (Bio-Rad) packed with protein A resin (TOYOPEARL AF-rProtein A Hc-650F). The IgG1 antibody was eluted with 3.5 ml of glycine-HCl (100mM, pH 2.7), immediately neutralized with 1 M Tris-HCl (pH 8.5), dialyzed in 1× PBS buffer (Ph 7.2) using Thermo Scientific® Slide-A-Lyzer® G2 Dialysis Cassettes (20K MWCO), and stored at 4°C. The concentration of the purified IgG1 antibody was determined using NanoDrop® One / One C The quality of IgG1 antibodies was measured using a Microvolume UV-Vis Spectrophotometer (Thermo Scientific®) and examined by SDS-PAGE gel under both denatured and non-denatured conditions.

[0275] Example 4 Binding affinity of anti-CD79b antibody to human and cynomolgus monkey CD79b recombinant protein, as measured by ELISA and BLI. The binding affinity of anti-CD79b antibodies to human and cynomolgus monkey CD79b recombinant proteins was tested by ELISA. Human or cynomolgus monkey CD79b recombinant protein at a concentration of 1 ug / ml (in PBS buffer) was coated onto ELISA plates and left overnight. The ELISA plates were washed, blocked with blocking buffer (PBS + 1% BSA), and then incubated with serially diluted anti-CD79b primary antibodies. Anti-CD79b antibody binding was quantified using anti-human IgG HRP secondary antibody (Biolegend Catalog# 410902) and HRP substrate. The ELISA binding affinity of anti-CD79b antibodies to human and cynomolgus monkey CD79b recombinant proteins is shown in Table 1, Figure 1, and Figure 2.

[0276] The binding affinity of anti-CD79b antibodies to human CD79b recombinant protein was tested using BLI. 10 ug / ml of anti-CD79b antibody was captured with an anti-human IgG Fc probe (Gator Bio Catalog # 160024). Association and dissociation of serially diluted (2-fold dilution from 146 nM to 0 nM with PBS + 0.05% Tween-20) human CD79b recombinant protein were measured. Absolute kD was measured using a 1:1 binding model (Global Rmax unlinked). The BLI binding affinity of anti-CD79b antibodies to human CD79b recombinant protein is shown in Table 1 and Figure 3. Polatuzumab was included for comparison. For ch44G2, according to BLI data, the kon is 3.77E+05, but the koff is undetectable. This suggests that ch44G2 has a strong binding affinity to CD79b. [Table 1]

[0277] Example 5: Internalization of anti-CD79b antibody The internalization of anti-CD79b antibodies was evaluated. Approximately 50,000 Ramos cells (per time point) were incubated with 20 ug / ml of labeled anti-CD79b antibody at 37°C. At different time points, cells were washed, and the presence of anti-CD79b antibody-binding receptors was detected using anti-human IgG PE secondary antibody (Jackson Research Catalog # 109-116-170). For analysis, the mean fluorescence intensity (MFI(PE)) of each antibody was normalized to its respective zero time point (100%), and the decrease in percentage MFI(PE) over time was plotted. As shown in Figure 4, all screened anti-CD79b antibodies internalized more slowly than polatuzumab. In particular, ch23D8, ch44G2, ch48H10, and ch57B9 showed significantly slower internalization than the other antibodies.

[0278] Example 6: Quantification of CD79b antigen density on tumor cell surface To estimate the CD79b antigen expression levels on the surface of malignant B tumor cells and normal B cells, cell lines and PBMCs from two healthy donors were stained with saturating anti-CD79b antibody ch44G2 on ice for 30 minutes. After washing with PBS, the cells were stained with secondary PE-labeled anti-human IgG (Invitrogen, Cat: 12-4998-82) on ice for 30 minutes. Next, the cells were washed with PBS and resuspended in FACS buffer for flow cytometry analysis using Cytek northern lights. The results were analyzed and graphed using GraphPad prism software (version 9.4.1, GraphPad Software Inc.). The quantification of CD79b antigen density on the surface of malignant B tumor cells and normal B cells is shown in Table 2 and Figure 5. [Table 2]

[0279] Example 7: Malignant B-cell binding assay The binding affinity of anti-CD79b antibodies to malignant B cell lines was tested. Polatuzumab and IgG1 were used as positive and negative controls, respectively. Malignant B cell lines (BJAB, Ramos, Daudi, SU-DHL-4, and Nalm-6) at 50,000 cells / well in 96-well plates were incubated on ice for 30 minutes at different concentrations (1:3 serial dilutions starting from 40 nM) with anti-CD79b antibodies (ch22D10, ch23D8, ch29C3, ch44G2, ch48H10, ch57B9, and polatuzumab) and IgG1 (Biolegend, Cat#:403502), and washed twice with 200 ul of PBS. Next, cells were incubated with 100 μl of 1:1000 dilution of anti-human IgG1-PE (Invitrogen, cat:12-4998-82) on ice for 30 minutes and washed three times with 200 μl of PBS before flow cytometry analysis. As shown in Figures 6-10, the anti-CD79b antibodies ch23D8, ch44G2, ch48H10, and ch57B9 showed higher cell surface binding affinity (lower EC50) to BJAB (Figure 6), Ramos (Figure 7), Daudi (Figure 8), SU-DHL-4 (Figure 9), and Nalm-6 (Figure 10) than polatuzumab. The results showed that ch23D8, ch44G2, ch48H10, and ch57B9 could bind to malignant B cell lines at both high and low CD79b antigen densities.

[0280] Example 8 Endogenous B-cell binding assay The binding affinity of anti-CD79b antibodies to endogenous B cells was tested. Polatuzumab and IgG1 controls were used as positive and negative controls, respectively. PBMCs at 200,000 cells / well in 96-well plates from four donors (Stanford Blood Center) were incubated on ice for 30 minutes at different concentrations (1:5 serial dilutions from 50 nM) with anti-CD79b antibodies (ch23D8, ch44G2, ch48H10, and polatuzumab) and IgG1 (Biolegend, Cat#:403502), and washed twice with 200 ul of PBS. Next, the cells were incubated on ice for 30 minutes with 100 μl of a mixture of anti-human IgG1-PE (Invitrogen, Cat#:12-4998-82) at a 1:1000 dilution and CD19-BV421 (Biolegend, Cat#:302230, 1:400 dilution), and washed three times with 200 μl of PBS before flow cytometry analysis. As shown in Figures 11–14, ch44G2, ch48H10, and ch23D8 showed higher cell surface binding affinity to endogenous B cells than polatuzumab in all four different donors.

[0281] Example 9: PBMC binding assay in a CLL patient A cell-based binding assay was performed to measure the binding affinity of an anti-CD79b antibody to cell surface CD79b on B lymphocytes of patients with chronic lymphocytic leukemia (CLL). Polatuzumab and IgG1 control were used as positive and negative controls, respectively. PBMCs from CLL patients were purchased from Bioscience. FACS analysis showed that 95% of B lymphocytes (CD19+) in the PBMCs were positive. Specifically, 2.5 × 10⁶ cells in 50 μl of FACS buffer (1 × PBS + 2% BSA + 2 mM EDTA) were positive. 4100 PBMC cells were seeded in each well of a V-bottom 96-well plate. Next, 50 μl of serially diluted anti-CD79b antibody (ch22D10, ch23D8, ch29C3, ch44G2, ch48H10, ch57B9, or polatuzumab) or IgG1 was added to each well. The mixture was incubated on ice for 30 minutes, and then washed twice with FACS buffer. The cells were resuspended in 100 μl of FACS buffer containing PE conjugate goat anti-human IgG Fc (1:1000) and anti-human CD19 (BV421), and incubated on ice in the dark for 30 minutes. After washing twice with FACS buffer, the cells were resuspended in 100 μl of FACS buffer and analyzed with a Cytek cytometer. As shown in Figures 15-16, ch23D8, ch44G2, ch48H10, and ch57B9 bound more strongly to B lymphocytes in CLL patients than polatuzumab.

[0282] Example 10 CD79b mAb bound to long and short isoforms of CD79b Surface binding of anti-CD79b antibodies to both the long and short isoforms of CD79b was performed. Polatuzumab was used as a positive control. Approximately 2 million Nalm-6 cells were electroporated with expression plasmids encoding the short isoform (Nalm-6+ short isoform) and long isoform (Nalm-6+ long isoform) of CD79b separately. After 48 hours, the cells were stained with the specified anti-CD79b antibodies (ch23D8, ch44G2, or polatuzumab) and detected with anti-IgM-APC (BD bioscience, Catalog# 551062). As shown in Figures 17A-17B, ch23D8 and ch44G2 have strong binding affinity to both the long and short isoforms of CD79b.

[0283] Example 11 Humanization of anti-CD79b antibody Four rabbit anti-human CD79b monoclonal antibody clones, 23D8, 44G2, 48H10, and 57B9, were humanized by transplanting the CDRs of major antibodies into selected human germline frameworks that most closely matched the rabbit framework identified by IgBLAST (https: / / www.ncbi.nlm.nih.gov / igblast / ) and / or IMGT / DomainGapAlig (https: / / www.imgt.org / 3Dstructure-DB / cgi / DomainGapAlign.cgi). Human germline cells IGHV, IGKV, IGHJ, and IGKJ were selected based on sequence similarity in both the framework and the CDR. To maintain the standard loop structure and light / heavy chain interface, specific human germline framework residues were reverse-mutated to their corresponding rabbit residues (Padlan Mol. Immunol., 1994, 31:169; Foote and Winter JMB, 1992, 224:487; Padlan Mol. Immunol., 1994, 31:169). Humanization generated humanized antibodies for hu23D8, hu44G2, hu48H10, and hu57B9.

[0284] The thermal stability of humanized antibody clones was evaluated using Nano DSF (Table 3). Humanized antibodies were confirmed to bind to recombinant human CD79b ECD in ELISA (Figure 18) and to cell lines expressing endogenous CD79b (Figure 19).

[0285] The results showed that the humanized anti-CD79b antibody exhibited the same technical effects as the chimeric anti-CD79b antibody, such as high affinity for CD79b, slow internalization, high binding to malignant B cell lines at both high and low CD79b antigen densities, high cell surface binding affinity to endogenous B cells, high binding to B lymphocytes in CLL patients, and strong binding affinity to both the long and short isoforms of CD79b. [Table 3] Other Embodiments

[0286] Although the present invention has been described in connection with its detailed description, the foregoing description is illustrative and not intended to limit the scope of the invention, and it should be understood that the scope of the invention is defined by the appended claims. Other aspects, advantages, and modifications are within the scope of the following claims.

Claims

1. An antibody or antigen-binding fragment thereof that binds to CD79b (differentiation antigen group 79B), A heavy chain variable region (VH) including complementarity-determining regions (CDRs) 1, 2, and 3, A light chain variable region (VL) including CDR1, 2, and 3, The VH and VL are, (1) According to the Kabat definition, the VH comprises CDR1, 2, and 3 having the amino acid sequences shown in SEQ ID NOs. 39, 41, and 43, respectively, and the VL comprises CDR1, 2, and 3 having the amino acid sequences shown in SEQ ID NOs. 44 to 46, respectively. (2) According to the Kotia definition, the VH comprises CDR1, 2, and 3 having the amino acid sequences shown in SEQ ID NOs. 40, 42, and 43, respectively, and the VL comprises CDR1, 2, and 3 having the amino acid sequences shown in SEQ ID NOs. 44 to 46, respectively. (3) According to the Kabat definition, the VH comprises CDR1, 2, and 3 having the amino acid sequences shown in SEQ ID NOs: 9, 11, and 13, respectively, and the VL comprises CDR1, 2, and 3 having the amino acid sequences shown in SEQ ID NOs: 14 to 16, respectively. (4) According to the Kabat definition, the VH comprises CDR1, 2, and 3 having the amino acid sequences shown in SEQ ID NOs: 19, 21, and 23, respectively, and the VL comprises CDR1, 2, and 3 having the amino acid sequences shown in SEQ ID NOs: 24 to 26, respectively. (5) According to the Kabat definition, the VH comprises CDR1, 2, and 3 having the amino acid sequences shown in SEQ ID NOs. 29, 31, and 33, respectively, and the VL comprises CDR1, 2, and 3 having the amino acid sequences shown in SEQ ID NOs. 34 to 36, respectively. (6) According to the Kabat definition, the VH comprises CDR1, 2, and 3 having the amino acid sequences shown in SEQ ID NOs. 49, 51, and 53, respectively, and the VL comprises CDR1, 2, and 3 having the amino acid sequences shown in SEQ ID NOs. 54 to 56, respectively. (7) According to the Kabat definition, the VH comprises CDR1, 2, and 3 having the amino acid sequences shown in SEQ ID NOs. 59, 61, and 63, respectively, and the VL comprises CDR1, 2, and 3 having the amino acid sequences shown in SEQ ID NOs. 64 to 66, respectively. (8) According to the Kotia definition, the VH comprises CDR1, 2, and 3 having the amino acid sequences shown in SEQ ID NOs: 10, 12, and 13, respectively, and the VL comprises CDR1, 2, and 3 having the amino acid sequences shown in SEQ ID NOs: 14 to 16, respectively. (9) According to the Kotia definition, the VH comprises CDR1, 2, and 3 having the amino acid sequences shown in SEQ ID NOs. 20, 22, and 23, respectively, and the VL comprises CDR1, 2, and 3 having the amino acid sequences shown in SEQ ID NOs. 24 to 26, respectively. (10) According to the Kotia definition, the VH comprises CDR1, 2, and 3 having the amino acid sequences shown in SEQ ID NOs: 30, 32, and 33, respectively, and the VL comprises CDR1, 2, and 3 having the amino acid sequences shown in SEQ ID NOs: 34 to 36, respectively. (11) According to the Kotia definition, the VH comprises CDR1, 2, and 3 having the amino acid sequences shown in SEQ ID NOs. 50, 52, and 53, respectively, and the VL comprises CDR1, 2, and 3 having the amino acid sequences shown in SEQ ID NOs. 54 to 56, respectively, and (12) According to the Kotia definition, the VH comprises CDR1, 2, and 3 having the amino acid sequences shown in SEQ ID NOs. 60, 62, and 63, respectively, and the VL comprises CDR1, 2, and 3 having the amino acid sequences shown in SEQ ID NOs. 64 to 66, respectively. One of these is an antibody or its antigen-binding fragment.

2. The antibody or antigen-binding fragment thereof according to claim 1, It comprises a heavy chain variable region (VH) containing an amino acid sequence that is at least 90% identical to the selected VH sequence, and a light chain variable region (VL) containing an amino acid sequence that is at least 90% identical to the selected VL sequence, wherein the selected VH sequence and the selected VL sequence are (1) The selected VH sequence is sequence number 37 or 71, and the selected VL sequence is sequence number 38 or 72, (2) The selected VH sequence is sequence number 7 and the selected VL sequence is sequence number 8, (3) The selected VH sequence is sequence number 17 or 69, and the selected VL sequence is sequence number 18 or 70, (4) The selected VH sequence is sequence number 27 and the selected VL sequence is sequence number 28, (5) The selected VH sequence is sequence number 47 or 73, and the selected VL sequence is sequence number 48 or 74, and (6) The selected VH sequence is sequence number 57 or 75, and the selected VL sequence is sequence number 58 or 76, One of these is an antibody or its antigen-binding fragment.

3. The antibody or antigen-binding fragment thereof according to Claim 2, The VH and VL are, (1) The VH includes the sequence of sequence number 37, and the VL includes the sequence of sequence number 38. (2) The VH includes the sequence of sequence number 71, and the VL includes the sequence of sequence number 72. (3) The VH includes the sequence of sequence number 7, and the VL includes the sequence of sequence number 8. (4) The VH includes the sequence of sequence number 17, and the VL includes the sequence of sequence number 18. (5) The VH includes the sequence of sequence number 27, and the VL includes the sequence of sequence number 28. (6) VH includes the sequence of sequence number 47, and VL includes the sequence of sequence number 48. (7) The VH includes the sequence of sequence number 57, and the VL includes the sequence of sequence number 58. (8) The VH includes the sequence of sequence number 69, and the VL includes the sequence of sequence number 70. (9) The VH includes the sequence of sequence number 73, the VL includes the sequence of sequence number 74, and (10) The VH includes the sequence of sequence number 75, and the VL includes the sequence of sequence number 76. One of these is an antibody or its antigen-binding fragment.

4. The antibody or antigen-binding fragment thereof according to claim 1, wherein the antibody or antigen-binding fragment thereof (1) The antibody or its antigen-binding fragment specifically binds to human, mouse, monkey, or canine CD79b. (2) The antibody or its antigen-binding fragment is a humanized antibody or its antigen-binding fragment, a single-chain variable fragment (scFv), a one-arm antibody, and / or a multispecific antibody. (3) The antibody or its antigen-binding fragment comprises human IgG1 Fc, human IgG2 Fc, or human IgG4 Fc, and / or (4) The antibody or its antigen-binding fragment includes a fragment crystallizable region (Fc region). An antibody or its antigen-binding fragment having one or more characteristics selected from the following.

5. An antibody that binds to CD79b or an antigen-binding fragment thereof, The selected VH sequence includes a heavy chain variable region (VH) containing VH CDR1, VH CDR2, and VH CDR3 identical to those of the selected VH sequence, and a light chain variable region (VL) containing VL CDR1, VL CDR2, and VL CDR3 identical to those of the selected VL sequence, wherein the selected VH sequence and the selected VL sequence are, (1) The selected VH sequence is sequence number 37 or 71, and the selected VL sequence is sequence number 38 or 72, (2) The selected VH sequence is sequence number 7 and the selected VL sequence is sequence number 8, (3) The selected VH sequence is sequence number 17 or 69, and the selected VL sequence is sequence number 18 or 70, (4) The selected VH sequence is sequence number 27 and the selected VL sequence is sequence number 28, (5) The selected VH sequence is sequence number 47 or 73, and the selected VL sequence is sequence number 48 or 74, and (6) The selected VH sequence is sequence number 57 or 75, and the selected VL sequence is sequence number 58 or 76, One of these is an antibody or its antigen-binding fragment.

6. The antibody or antigen-binding fragment thereof according to claim 5, wherein the antibody or antigen-binding fragment thereof (1) The antibody or its antigen-binding fragment specifically binds to human, mouse, monkey, or canine CD79b. (2) The antibody or its antigen-binding fragment is a humanized antibody or its antigen-binding fragment, a chimeric antibody, a single-chain variable fragment (scFv), a one-arm antibody, and / or a multispecific antibody. (3) The antibody or its antigen-binding fragment includes a human IgG1 constant region, a human IgG2 constant region, or a human IgG4 constant region. (4) The antibody or antigen-binding fragment comprises human IgG1 Fc, human IgG2 Fc, or human IgG4 Fc, and / or (5) The antibody or its antigen-binding fragment includes a fragment crystallizable region (Fc region), An antibody or its antigen-binding fragment having one or more characteristics selected from the following.

7. A nucleic acid comprising a polynucleotide encoding an antibody or an antigen-binding fragment thereof according to any one of claims 1 to 6.

8. The nucleic acid according to claim 7, wherein the nucleic acid is cDNA.

9. A vector comprising two of the nucleic acids described in claim 7, wherein the vector encodes a VL region and a VH region that both bind to CD79b.

10. A pair of vectors, each containing one of the nucleic acids described in claim 7, and both encoding a VL region and a VH region that bind to CD79b.

11. Two of the nucleic acids described in claim 7, both of which encode a VL region and a VH region that bind to CD79b, or A vector containing one or more of the aforementioned nucleic acids, or A pair of vectors, each containing one of the nucleic acids, and both encoding the VL region and VH region that bind to CD79b. A cell containing one of the following.

12. The cell according to claim 11, wherein the cell is a CHO cell.

13. A method for producing an antibody or its antigen-binding fragment, (a) Culturing the cells according to claim 11 under conditions sufficient for the cells to produce the antibody or the antigen-binding fragment, (b) A method comprising collecting the antibody or antigen-binding fragment produced by the cells.

14. A chimeric antigen receptor (CAR) comprising an antibody or an antigen-binding fragment thereof according to any one of claims 1 to 6.

15. An antibody-drug conjugate comprising an antibody according to any one of claims 1 to 6 or an antigen-binding fragment thereof covalently bound to a therapeutic agent,

16. The antibody-drug conjugate according to claim 15, wherein the therapeutic agent is a cytotoxic agent or a cell proliferation inhibitor.

17. A pharmaceutically acceptable carrier, An antibody or antigen-binding fragment thereof according to any one of claims 1 to 6, Antibody-drug conjugate comprising the antibody or its antigen-binding fragment and a therapeutic agent covalently bound thereto one of them A pharmaceutical composition containing the following.

18. A composition for treating a subject with cancer or autoimmune disease, An antibody or antigen-binding fragment thereof according to any one of claims 1 to 6, A chimeric antigen receptor (CAR) containing the aforementioned antibody or its antigen-binding fragment, or Antibody-drug conjugate comprising the antibody or its antigen-binding fragment and a therapeutic agent covalently bound thereto In a composition containing one of the following, The composition is characterized by the cancer being non-Hodgkin lymphoma (NHL), diffuse large B-cell lymphoma (DLBCL), acute lymphoblastic leukemia (B-ALL), chronic lymphocytic leukemia (CLL), B-cell prelymphocytic leukemia (PLL), splenic lymphoma with choriolymphocytes (SLVL), hairy cell leukemia (HCL), follicular lymphoma (FL), or mantle cell lymphoma (MCL).

19. The composition according to claim 18, wherein the autoimmune disease is selected from rheumatoid arthritis, psoriasis, multiple sclerosis, immune thrombocytopenic purpura, myasthenia gravis, neuromyelitis optica, IgG4-related disease, lupus, systemic lupus erythematosus, lupus nephritis, giant cell arteritis, Takayasu arteritis, cold agglutinin disease, warm autoimmune hemolytic anemia, and antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis, granulomatosis with polyangiitis (GPA) (Wegener's granulomatosis), microscopic polyangiitis (MPA), inflammatory bowel disease (IBD), or autoreactive pancreatitis.

20. The composition according to claim 18, wherein the subject is further treated with an effective amount of anti-4-1BB antibody, anti-OX40 antibody, anti-PD-1 antibody, anti-PD-L1 antibody, anti-CTLA4 antibody, anti-CD40 antibody, BTK inhibitor, or BCL2 inhibitor.

21. A composition for reducing the growth rate of a tumor, An antibody or antigen-binding fragment thereof according to any one of claims 1 to 6, A chimeric antigen receptor (CAR) containing the aforementioned antibody or its antigen-binding fragment, or Antibody-drug conjugate comprising the antibody or its antigen-binding fragment and a therapeutic agent covalently bound thereto A composition containing one of the following.

22. A composition for killing tumor cells, An antibody or antigen-binding fragment thereof according to any one of claims 1 to 6, A chimeric antigen receptor (CAR) containing the aforementioned antibody or its antigen-binding fragment, or Antibody-drug conjugate comprising the antibody or its antigen-binding fragment and a therapeutic agent covalently bound thereto A composition containing one of the following.

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