Compositions of multispecific antibodies and methods of use thereof

Abstract

Disclosed herein are multispecific antibodies targeting CD19, CD3 and CD20 and methods of their use for treating autoimmune diseases.

Description

WSGR Docket No. 69143-718.601COMPOSITIONS OF MULTISPECIFIC ANTIBODIES AND METHODS OF USE THEREOFCROSS REFERENCE

[0001] This application claims the benefit of U. S. Provisional Application No. 63 / 747,562, filed January' 21, 2025. This application also claims the benefit of U. S. Provisional Application No. 63 / 748,882, filed January 23, 2025, which is incorporated herein by reference in its entirety, and U. S. Provisional Application No. 63 / 848,545, filed July 22, 2025, which is incorporated herein by reference in its entirety.SEQUENCE LISTING

[0002] The instant application contains a Sequence Listing in electronic format. The Sequence Listing is provided as a file entitled 69143-718_601_SL.xml, created on January 14, 2026, which is 49,361 bytes in size. The information in the electronic format of the Sequence Listing is incorporated by reference in its entirety.BACKGROUND

[0003] Autoimmune diseases represent a group of chronic, debilitating conditions in which the immune system erroneously targets and attacks the body’s own cells, tissues, and organs. These diseases affect millions of people in the United States, and the social, economic, and healthcare burdens of these diseases are profound. Thus, there is a pressing need for improved therapeutic modalities that offer enhanced efficacy, durability', and safety profiles.SUMMARY

[0004] Disclosed herein is a method for treating an autoimmune disease or disorder in a subject, comprising administering to the subject a therapeutically effective amount of (i) an antibody or antigenbinding portion thereof comprising a CD 19 binding moiety, a CD3 binding moiety and a CD20 binding moiety, or (ii) one or more polynucleotide encoding the antibody or antigen-binding portion thereof; wherein (a) the CD 19 binding moiety comprises a heavy chain complementarity determining region (HCDR) 1, a HCDR2 and a HCDR3 comprising the amino acid sequences of SEQ ID NOs: 1, 2 and 3, respectively, and a light chain complementarity determining region (LCDR) 1, a LCDR2 and a LCDR3 comprising the amino acid sequences of SEQ ID NOs: 4, 5 and 6, respectively; ( b) the CD3 binding moiety comprises a HCDR1, a HCDR2 and a HCDR3 comprising the amino acid sequences of SEQ ID NOs: 7, 8 and 9, respectively, and a LCDR1, a LCDR2 and a LCDR3 comprising the amino acid sequences of SEQ ID NOs: 10, 11 and 12, respectively; and (c) the CD20 binding moiety comprises a HCDR1, a HCDR2 and a HCDR3 comprising the amino acid sequences of SEQ ID NOs: 13, 14 and 15, respectively, and a LCDRl, a LCDR2 and a LCDR3 comprising the amino acid sequences of SEQ ID NOs: 16, 17 and 18, respectively. In some embodiments, the autoimmune disease or disorder comprises an autoantibody-driven disease. In some embodiments, the autoimmune disease or disorder comprises a disease mediated by an autoantibody. In some embodiments, the autoimmune disease or disorder comprises a disease mediated by a B cell, a plasmablast, or a plasma cell. In some embodiments, the autoimmune disease or disorder comprises a disease mediated by a mature B cell, a memory B cell, or anWSGR Docket No. 69143-718.601activated B cell. In some embodiments, the autoimmune disease or disorder comprises allergy, antibody-mediated rejection, alloantibodies, a disease related to or mediated by an alloantibody, amyloidosis, anti-glomerular basement membrane (GBM) (Goodpasture Syndrome), anti-N-methyl-D-aspartate receptor (NMDA) encephalitis (anti -NMD A-R Encephalitis), anti-neutrophil cytoplasmic autoantibody-associated vasculitis (ANCA vasculitis), antiphospholipid antibody syndrome, antisynthetase Syndrome, atopic dermatitis, autoimmune hepatitis, autoimmune necrotizing myopathy, Behcet’s disease. Bullous Pemphigoid, Celiac disease, Chronic Inflammatory Demyelinating Polyneuropathy (CIDP), Crohn’s disease, dilated cardiomyopathy, Graves, Guillain Barre Syndrome, Hidradenitis Suppurativa, IgA Nephropathy, Immunoglobulin G4-related disease (IgG4-RD), immune vasculitis (IgA), immune thrombocytopenia (ITP), Long COVID, Lupus Nephritis, Membranous Nephropathy, microscopic polyangiitis, multiple sclerosis (MS) - primary progressive multiple sclerosis (MS-PPMS), multiple sclerosis (MS) -relapsing-remitting multiple sclerosis (MS-RRMS), Myasthenia Gravis, myositis-dermatomyositis, myositis-inclusion body, myositis-polymyositis, myositis- immune-mediated necrotizing myositis, neuromyelitis optica spectrum disorder (NMOSD), Pemphigus Vulgaris, polyneuropathy, organomegaly, endocrinopathy, M-protein and skin changes (POEMS) syndrome, Polyarteritis Nodosa, Postural Orthostatic Tachycardia Syndrome (POTS), Primary Biliary Cirrhosis, Primary Sclerosing Cholangitis, Psoriasis, Psoriatic Arthritis, Raynaud’s Syndrome, Reactive Arthritis, rheumatoid arthritis, scleroderma or systemic sclerosis, Sjogren’s Syndrome, Stiff Person Syndrome, Type 1 diabetes, Thyroid eye disease, tumor progression, or ulcerative colitis. In some embodiments, the autoimmune disease or disorder comprises allergy. In some embodiments, the autoimmune disease or disorder comprises antibody-mediated rejection. In some embodiments, the autoimmune disease or disorder comprises alloantibodies. In some embodiments, the autoimmune disease or disorder comprises a disease related to or mediated by an alloantibody. In some embodiments, the autoimmune disease or disorder comprises amyloidosis. In some embodiments, the autoimmune disease or disorder comprises anti-GBM (Goodpasture Syndrome). In some embodiments, the autoimmune disease or disorder comprises anti-NMDA-R Encephalitis. In some embodiments, the autoimmune disease or disorder comprises ANCA vasculitis. In some embodiments, the autoimmune disease or disorder comprises antiphospholipid antibody syndrome. In some embodiments, the autoimmune disease or disorder comprises antisynthetase Syndrome. In some embodiments, the autoimmune disease or disorder comprises atopic dermatitis. In some embodiments, the autoimmune disease or disorder comprises autoimmune hepatitis. In some embodiments, the autoimmune disease or disorder comprises autoimmune necrotizing myopathy. In some embodiments, the autoimmune disease or disorder comprises Behcet’s disease. In some embodiments, the autoimmune disease or disorder comprises Bullous Pemphigoid. In some embodiments, the autoimmune disease or disorder comprises Celiac disease. In some embodiments, the autoimmune disease or disorder comprises CIDP. In some embodiments, the autoimmune disease or disorder comprises Crohn’s disease. In some embodiments, the autoimmune disease or disorder comprises dilated cardiomyopathy. In some embodiments, the autoimmune disease or disorder comprises Graves. In some embodiments, the autoimmune disease or disorder comprises Guillain Barre Syndrome. In some embodiments, the autoimmune disease or disorder comprises HidradenitisWSGR Docket No. 69143-718.601Suppurativa. In some embodiments, the autoimmune disease or disorder comprises IgA Nephropathy. In some embodiments, the autoimmune disease or disorder comprises IgG4-RD. In some embodiments, the autoimmune disease or disorder comprises immune vasculitis (IgA). In some embodiments, the autoimmune disease or disorder comprises ITP, In some embodiments, the autoimmune disease or disorder comprises Long COVID. In some embodiments, the autoimmune disease or disorder comprises Lupus Nephritis. In some embodiments, the autoimmune disease or disorder comprises Membranous Nephropathy. In some embodiments, the autoimmune disease or disorder comprises microscopic polyangiitis. In some embodiments, the autoimmune disease or disorder comprises MS-PPMS. In some embodiments, the autoimmune disease or disorder comprises MS-RRMS In some embodiments, the autoimmune disease or disorder comprises Myasthenia Gravis. In some embodiments, the autoimmune disease or disorder comprises myositis-dermatomyositis. In some embodiments, the autoimmune disease or disorder comprises myositis-inclusion body. In some embodiments, the autoimmune disease or disorder comprises myositis-polymyositis. In some embodiments, the autoimmune disease or disorder comprises myositis-immune-mediated necrotizing myositis. In some embodiments, the autoimmune disease or disorder comprises NMOSD. In some embodiments, the autoimmune disease or disorder comprises Pemphigus Vulgaris. In some embodiments, the autoimmune disease or disorder comprises POEMS syndrome. In some embodiments, the autoimmune disease or disorder comprises POTS. In some embodiments, the autoimmune disease or disorder comprises Polyarteritis Nodosa. In some embodiments, the autoimmune disease or disorder comprises Primary Biliary Cirrhosis. In some embodiments, the autoimmune disease or disorder comprises Primary Sclerosing Cholangitis. In some embodiments, the autoimmune disease or disorder comprises Psoriasis. In some embodiments, the autoimmune disease or disorder comprises Psoriatic Arthritis. In some embodiments, the autoimmune disease or disorder comprises Raynaud’s Syndrome. In some embodiments, the autoimmune disease or disorder comprises Reactive Arthritis. In some embodiments, the autoimmune disease or disorder comprises rheumatoid arthritis. In some embodiments, the autoimmune disease or disorder comprises scleroderma or systemic sclerosis. In some embodiments, the autoimmune disease or disorder comprises Sjogren’s Syndrome. In some embodiments, the autoimmune disease or disorder comprises Stiff Person Syndrome. In some embodiments, the autoimmune disease or disorder comprises Type 1 diabetes. In some embodiments, the autoimmune disease or disorder comprises Thyroid eye disease. In some embodiments, the autoimmune disease or disorder comprises tumor progression. In some embodiments, the autoimmune disease or disorder comprises ulcerative colitis. In some embodiments, the subject is a human or non-human primate. In some embodiments, the subject is a human and is diagnosed with the autoimmune disease or disorder or suspected to have the autoimmune disease or disorder,

[0005] In some embodiments, the therapeutically effective amount of the antibody or antigen -binding portion thereof is calculated based on a biomarker. In some embodiments, the method further comprises measuring a biomarker in the subject. In some embodiments, the biomarker comprises a B cell, a plasmablast, a plasma cell, an autoantibody, or an immunoglobulin (Ig). In some embodiments, the biomarker comprises a mature B cell, a memory B cell, or an activated B cell. In some embodiments, the biomarker comprises a free kappa light chain or a free lambda light chain. In some embodiments, theWSGR Docket No. 69143-718.601immunoglobulin comprises IgD, IgG, IgA, or IgM. In some embodiments, the therapeutically effective amount is calculated based on an amount of the biomarker, in some embodiments, the therapeutically effective amount is calculated based on an amount of the biomarker in tonsil, mucosal lamina propria (LP), blood, spleen, lymph node, or bone marrow, and optionally the lymph node is mesenteric lymph node. In some embodiments, the therapeutically effective amount is calculated based on a reduction in the amount of the biomarker in the tonsil, mucosal LP, blood, spleen, lymph node, or bone marrow after the administering, and optionally the lymph node is mesenteric lymph node. In some embodiments, the antibody or antigen-binding portion thereof is administered subcutaneously, intramuscularly or intravenously. In some embodiments, the administering results in elimination or reduction of a B cell, a plasmablast, or a plasma cell. In some embodiments, the administering results in elimination or reduction of a mature B cell, a memory B cell, or an activated B cell. In some embodiments, the administering results in elimination or reduction of an autoantibody. In some embodiments, the administering results in elimination or reduction of the B cell, the plasmablast, or the plasma cell through antibody -dependent cellular cytotoxicity (ADCC), antibody-dependent cell phagocytosis (ADCP), and / or complement¬ dependent cytotoxicity (CDC). In some embodiments, the administering results in elimination or reduction of the B cell, the plasmablast, or the plasma cell and the B cell, the plasmablast, or the plasma cell expresses CD 19. In some embodiments, the administering results in elimination or reduction of the B cell, the plasmablast, or the plasma cell and the B cell, the plasmablast, or the plasma cell expresses CD20. In some embodiments, the administering results in elimination or reduction of the B cell, the plasmablast, or the plasma cell and the B cell, the plasmablast, or the plasma cell expresses CD19 and CD20, or CD 138. In some embodiments, the B cell, the plasmablast, or the plasma cell is in tonsil, mucosal lamina propria (LP), blood, spleen, lymph node, or bone marrow. In some embodiments, the lymph node is mesenteric lymph node. In some embodiments, the administering results in an increase of a concentration of a cytokine and optionally the cytokine is in the serum. In some embodiments, the cytokine comprises interleukin 2 (IL-2), IL-6, interferon gamma (IFN-y), tumor necrosis factor alpha (TNF-a), or any combination thereof. In some embodiments, the increase of the concentration of the cytokine is transient or the concentration of the cytokine returns to a level similar to or same as a le vel before the administering after the increase. In some embodiments, the administering results in elimination or reduction of T cells. In some embodiments, the elimination or reduction of T cells is transient, or the number of T cells returns a level similar to, same as, or higher than, a level before the administering after the elimination or reduction. In some embodiments, the T cells are early activated T cells, late activated T cells, or proliferating T cells. In some embodiments, the T cells express CD69, CD25, Ki-67, or any combination thereof. In some embodiments, the administering results in an increase in the expression of CD25, CD69, or both, in T cells. In some embodiments, the T cells comprise CD4-positive T cells, CD8- positive T cells, or both. In some embodiments, the T cells are from tonsil, mucosal lamina propria (LP), blood, spleen, lymph node, or bone marrow, and optionally the lymph node is mesenteric lymph node. In some embodiments, the subject is a monkey. In some embodiments, the subject is a cynomolgus monkey. In some embodiments, the method further comprises administering a single dose or multiple doses of the antibody or antigen-binding fragment thereof. In some embodiments, the method further comprisesWSGR Docket No. 69143-718.601administering the antibody or antigen-binding fragment thereof on a weekly basis. In some embodiments, the method further comprises administering a single dose of 0.5 mg / kg, 1.5 mg / kg, 5 mg / kg, or 15 mg / kg of the antibody or antigen-binding fragment thereof on day 1 and the dose is calculated based on the weight of the subject. In some embodiments, the method further comprises administering a first dose and a second dose of the antibody or antigen-binding fragment thereof, wherein the first dose is administered on day 1 and the second dose is administered on day 8. In some embodiments, the first dose and second dose are both 15 mg / kg and the dose is calculated based on the weight of the subject. In some embodiments, the first dose and second dose are 1 mg / kg and 100 mg / kg, respectively, and the dose is calculated based on the weight of the subject. In some embodiments, the administering results in a transient increase of IL-6 and INF-y levels in the serum within 8 hours after the administering on day 1. In some embodiments, the IL-6 and INF-y levels in the serum are similar to or the same as the levels before the administering within 24 to 48 hours after the administering on day 1, In some embodiments, the administering results in elimination or reduction of B cells in the blood within 4 hours or 24 hours after the administering. In some embodiments, the administering results in elimination of B cells in the blood within 3 or 7 days after the administering. In some embodiments, the administering results in elimination of B cells in the blood that lasts at least until day 15 after the administering the second dose. In some embodiments, the administering results in elimination or reduction of T cells in the blood within 4 or 24 hours after the administering, wherein after the elimination or reduction, the number of T cells increases to a level that is higher than a level before the administering by day 8. In some embodiments, the administering results in an increase of T cells in the blood within 4 hours or 24 hours after the administering, wherein the T cells express CD69, CD25, Ki-67, or any combination thereof, wherein after the increase, the number of T cells is higher than the amount before the administering by day 8. In some embodiments, the number of T cells in the blood is the same as or higher than the number of T cells before the administering by day 15 after the administering the second dose. In some embodiments, the administering results in elimination or reduction of B cells in the bone marrow, spleen, or mesenteric lymph node and the percentage of elimination or reduction of B cells increases when the dose becomes higher. In some embodiments, the administering results in elimination or reduction of B cells in the bone marrow, spleen, and mesenteric lymph node and the percentage of elimination or reduction of B cells increases when the dose becomes higher. In some embodiments, the administering results in elimination of B cells in the bone marrow, spleen, and mesenteric lymph node at 5 mg / kg or higher doses. In some embodiments, the B cells express CD19, CD20, CD138, or any combination thereof. In some embodiments, the reduction of B cells is about 0-100%. In some embodiments, the method further comprises revaccinating the subject. In some embodiments, the method further comprises administering to the subject a pharmaceutical composition comprising the antibody or antigen -binding fragment thereof or the one or more polynucleotide encoding the antibody or antigen-binding portion thereof, and a pharmaceutically acceptable carrier or excipient.

[0006] In some embodiments, the CD19 binding moiety comprises a heavy chain variable region (CD19VH) and a light chain variable region (CD19VL); the CD3 binding moiety comprises a heavy chain variable region (CD3VH) and a light chain variable region (CD3VL); and the CD20 binding moietyWSGR Docket No. 69143-718.601comprises a heavy chain variable region (CD20VH) and a light chain variable region (CD20VL). In some embodiments, the antibody or antigen-binding portion thereof further comprises a first binding arm and a second binding arm, wherein the first binding arm comprises the CD 19 binding moiety and the CD3 binding moiety and the second binding arm comprises the CD20 binding moiety. In some embodiments, the CD19VH comprises an amino acid sequence with at least 90% sequence identity to SEQ ID NO: 19; the CD19VL comprises an amino acid sequence with at least 90% sequence identity to SEQ ID NO: 20; the CD3 VH comprises an amino acid sequence with at least 90% sequence identity to SEQ ID NO: 21; the CD3VL comprises an amino acid sequence with at least 90% sequence identity to SEQ ID NO: 22; the CD20VH comprises an amino acid sequence with at least 90% sequence identity to SEQ ID NO: 23; or the CD20VL comprises an amino acid sequence with at least 90% sequence identity to SEQ ID NO: 24. In some embodiments, the CD19VH comprises an amino acid sequence with at least 90% sequence identity to SEQ ID NO: 19; the CD19VL comprises an amino acid sequence with at least 90% sequence identity to SEQ ID NO: 20; the CD3VH comprises an amino acid sequence with at least 90% sequence identity to SEQ ID NO: 21; the CD3VL comprises an amino acid sequence with at least 90% sequence identity to SEQ ID NO: 22; the CD20VH comprises an amino acid sequence with at least 90% sequence identity to SEQ ID NO: 23; and the CD20VL comprises an amino acid sequence with at least 90% sequence identity to SEQ ID NO: 24. In some embodiments, the CD19VH comprises an amino acid sequence with at least 95% sequence identity to SEQ ID NO: 19; the CD19VL comprises an amino acid sequence with at least 95% sequence identity to SEQ ID NO: 20; the CD3 VH comprises an amino acid sequence with at least 95% sequence identity to SEQ ID NO: 21; the CD3VL comprises an amino acid sequence with at least 95% sequence identity to SEQ ID NO: 22; the CD20VH comprises an amino acid sequence with at least 95% sequence identity to SEQ ID NO: 23; or the CD20VL comprises an amino acid sequence with at least 95% sequence identity to SEQ ID NO: 24. In some embodiments, the CD19VH comprises an amino acid sequence with at least 95% sequence identity to SEQ ID NO: 19; the CD19VL comprises an amino acid sequence with at least 95% sequence identity to SEQ ID NO: 20; the CD3VH comprises an amino acid sequence with at least 95% sequence identity to SEQ ID NO: 21; the CD3 VL comprises an amino acid sequence with at least 95% sequence identity to SEQ ID NO: 22; the CD20 VH comprises an amino acid sequence with at least 95% sequence identity to SEQ ID NO: 23; and the CD20VL comprises an amino acid sequence with at least 95% sequence identity to SEQ ID NO: 24. In some embodiments, the CD19VH comprises an amino acid sequence with at least 99% sequence identity to SEQ ID NO: 19; the CD19VL comprises an amino acid sequence with at least 99% sequence identity to SEQ ID NO: 20; the CD3VH comprises an amino acid sequence with at least 99% sequence identity to SEQ ID NO: 21; the CD3VL comprises an amino acid sequence with at least 99% sequence identity to SEQ ID NO: 22; the CD20VH comprises an amino acid sequence with at least 99% sequence identity to SEQ ID NO: 23; or the CD20VL comprises an amino acid sequence with at least 99% sequence identity to SEQ ID NO: 24. In some embodiments, the CD19VH comprises an amino acid sequence with at least 99% sequence identity to SEQ ID NO: 19; the CD19VL comprises an amino acid sequence with at least 99% sequence identity to SEQ ID NO: 20; the CD3VH comprises an amino acid sequence with at least 99% sequence identity to SEQ ID NO: 21; the CD3VL comprises an amino acidWSGR Docket No. 69143-718.601sequence with at least 99% sequence identity to SEQ ID NO: 22; the CD20VH comprises an amino acid sequence with at least 99% sequence identity to SEQ ID NO: 23; and the CD20VL comprises an amino acid sequence with at least 99% sequence identity to SEQ ID NO: 24. In some embodiments, the CD19VH comprises the amino acid sequence of SEQ ID NO: 19; the CD19VL comprises the amino acid sequence of SEQ ID NO: 20; the CD3VH comprises the amino acid sequence of SEQ ID NO: 21; the CD3VL comprises the amino acid sequence of SEQ ID NO: 22; the CD20VH comprises the amino acid sequence of SEQ ID NO: 23; or the CD20VL comprises the amino acid sequence of SEQ ID NO: 24. In some embodiments, the CD19VH comprises the amino acid sequence of SEQ ID NO: 19; the CD19VL comprises the amino acid sequence of SEQ ID NO: 20; the CD3VH comprises the amino acid sequence of SEQ ID NO: 21; the CD3VL comprises the amino acid sequence of SEQ ID NO: 22; the CD20VH comprises the amino acid sequence of SEQ ID NO: 23; and the CD20VL comprises the amino acid sequence of SEQ ID NO: 24. In some embodiments, the CD19VH is operably linked to a first heavy chain constant domain (Cm); the CD19VL is operably linked to a first light chain constant domain (Cm); the CD3VH is operably linked to a second heavy chain constant domain (C2H); the CD3VL is operably linked to a second light chain constant domain (€%); the CD20VH is operably linked to a third heavy chain constant domain (C3H); or the CD20VL is operably linked to a third light chain constant domain (C3L). In some embodiments, the CD19VH is operably linked to a first heavy chain constant domain (Cm); the CD19VL is operably linked to a first light chain constant domain (C1L); the CD3VH is operably linked to a second heavy chain constant domain (C2H); the CD3VL is operably linked to a second light chain constant domain (C2L); the CD20VH is operably linked to a third heavy chain constant domain (CSH); and the CD20VL is operably linked to a third light chain constant domain (C31,). In some embodiments, the C1H and C1L comprise a T cell receptor (TCR) α chain constant domain (Cα) and a TCR β chain constant domain (Cβ), respectively; the C1H and C1L comprise Cβ and Cα, respectively; or the C1H and C1L comprise an antibody heavy chain constant region CH1 domain and an antibody light chain constant region CL domain, respectively. In some embodiments, the C1H and the C1L comprise Cα and Cβ, respectively. In some embodiments, the C1H and the C1L comprise Cβ and Cα, respectively. In some embodiments, the C1H and the C1L comprise CH1 domain and CL domain, respectively. In some embodiments, the C2H and the C2L comprise Caand Cp, respectively; the C2H and the C2L comprise Cβ and Cα, respectively; or the C211 and the C21. comprise CHI domain and CI, domain, respectively. In some embodiments, the C2H and the C2L comprise Cα and Cβ, respectively. In some embodiments, the C2H and the C2L comprise Cp and Ca, respectively. In some embodiments, the C2H and the C21, comprise CHI domain and CL domain, respectively. In some embodiments, the C3H and the C3L comprise Cα and Cβ, respectively; the C3H and the C3L comprise Cβ and Cα, respectively; or the C3H and the C3L comprise CH1 domain and CL domain, respectively. In some embodiments, the C3H and the C3L comprise Cα and Cβ, respectively. In some embodiments, the C3H and the C3L comprise Cβ and Cα, respectively. In some embodiments, the C3H and the C3L comprise CH1 domain and CL domain, respectively. In some embodiments, the C1H and the C1L comprise Cβ and Cα, respectively; the C2H and the C2L comprise Cβ and Cα, respectively; and the C3H and the C3L comprise CH1 domain and CL domain, respectively. In some embodiments, Cacomprises an amino acid sequence with at least 90% sequence identity to SEQ ID NO: 31; Cp comprises an amino acidWSGR Docket No. 69143-718.601sequence with at least 90% sequence identity to SEQ ID NO: 30; CHI domain comprises an amino acid sequence with at least 90% sequence identity to SEQ ID NO: 36; or CL domain comprises an amino acid sequence with at least 90% sequence identity to SEQ ID NO: 37. In some embodiments, Cacomprises an amino acid sequence with at least 90% sequence identity to SEQ ID NO: 31; Cp comprises an ammo acid sequence with at least 90% sequence identity to SEQ ID NO: 30; CHI domain comprises an amino acid sequence with at least 90% sequence identity to SEQ ID NO: 36; and CL domain comprises an amino acid sequence with at least 90% sequence identity to SEQ ID NO: 37. In some embodiments, Cacomprises an amino acid sequence with at least 95% sequence identity to SEQ ID NO: 31; Cβ comprises an amino acid sequence with at least 95% sequence identity to SEQ ID NO: 30; CHI domain comprises an amino acid sequence with at least 95% sequence identity to SEQ ID NO: 36; or CL domain comprises an amino acid sequence with at least 95 % sequence identity to SEQ ID NO: 37. In some embodiments, Cacomprises an amino acid sequence with at least 95% sequence identity to SEQ ID NO: 31; Cβ comprises an amino acid sequence with at least 95% sequence identity to SEQ ID NO: 30; CH1 domain comprises an amino acid sequence with at least 95% sequence identity to SEQ ID NO: 36; and CL domain comprises an amino acid sequence with at least 95% sequence identity to SEQ ID NO: 37. In some embodiments, Cα comprises an amino acid sequence with at least 99% sequence identity to SEQ ID NO: 31; Cβ comprises an amino acid sequence with at least 99% sequence identity to SEQ ID NO: 30; CHI domain comprises an amino acid sequence with at least 99% sequence identity to SEQ ID NO: 36; or CL domain comprises an amino acid sequence with at least 99% sequence identity to SEQ ID NO: 37. In some embodiments, Cacomprises an amino acid sequence with at least 99% sequence identity to SEQ ID NO: 31; Cβ comprises an amino acid sequence with at least 99% sequence identity to SEQ ID NO: 30; CH1 domain comprises an amino acid sequence with at least 99% sequence identity to SEQ ID NO: 36; and CL domain comprises an amino acid sequence with at least 99% sequence identity to SEQ ID NO: 37. In some embodiments, Cα comprises the amino acid sequence of SEQ ID NO: 31; Cβ comprises the amino acid sequence of SEQ ID NO: 30; CH1 domain comprises the amino acid sequence of SEQ ID NO: 36; or CL domain comprises the amino acid sequence of SEQ ID NO: 37. In some embodiments, Cα comprises the amino acid sequence of SEQ ID NO: 31; Cβ comprises the amino acid sequence of SEQ ID NO: 30; CH1 domain comprises the amino acid sequence of SEQ ID NO: 36; and CL domain comprises the amino acid sequence of SEQ ID NO: 37. In some embodiments, the C1H comprises the amino acid sequence of SEQ ID NO: 30; the C1L comprises the amino acid sequence of SEQ ID NO: 31; the C2H comprises the amino acid sequence of SEQ ID NO: 30; the C2L comprises the amino acid sequence of SEQ ID NO: 31; the C3H comprises the amino acid sequence of SEQ ID NO: 36; and the C3L comprises the amino acid sequence of SEQ ID NO: 37. In some embodiments, the CD19VH is covalently linked to the C1H directly or via a peptide linker; the CD19VL is covalently linked to the C1L directly or via a peptide linker; the CD3VH is covalently linked to the C2H directly or via a peptide linker; the CD3VL is covalently linked to the C2L directly or via a peptide linker; the CD20VH is covalently linked to the C3H directly or via a peptide linker; or the CD20VL is covalently linked to the C3L directly or via a peptide linker. In some embodiments, the CD19VH is covalently linked to the C1H directly; the CD19VL is covalently linked to the C1L directly; the CD3VH is covalently linked to the C2H directly; the CD3VL is covalently linked to the C2L directly; the CD20VH is covalently linkedWSGR Docket No. 69143-718.601to the C3H directly; or the CD20VL is covalently linked to the C3L directly. In some embodiments, the CD19VH is covalently linked to the C1H directly; the CD19VL is covalently linked to the C1L directly; the CD3VH is covalently linked to the C2H directly; the CD3VL is covalently linked to the C2L directly; the CD20VH is covalently linked to the C3H directly; and the CD20VL is covalently linked to the C3L directly. In some embodiments, the CD19VH is covalently linked to the C1H via a peptide linker; the CD19VL is covalently linked to the C1L via a peptide linker; the CD3VH is covalently linked to the C2H via a peptide linker; the CD3VL is covalently linked to the C2L via a peptide linker; the CD20VH is covalently linked to the C3H via a peptide linker; or the CD20VL is covalently linked to the C3L via a peptide linker. In some embodiments, the CD19VH is covalently linked to the C1H via a peptide linker; the CD19VL is covalently linked to the C1L via a peptide linker; the CD3VH is covalently linked to the C2H via a peptide linker; the CD3VL is covalently linked to the C2L via a peptide linker; the CD20VH is covalently linked to the C3H via a peptide linker; and the CD20VL is covalently linked to the C3L via a peptide linker. In some embodiments, the antibody or antigen-binding portion thereof further comprises a first heavy chain (HC1), a second heavy chain (HC2), a first light chain (LC1), a second light chain (LC2), or a third light chain (LC3). In some embodiments, the antibody or antigen-binding portion thereof further comprises tire first heavy chain (HC1), the second heavy chain (HC2), the first light chain (LC1), the second light chain (LC2), and the third light chain (LC3). In some embodiments, the antibody or antigen -binding portion thereof further comprises a fragment crystallizable (Fc) region. In some embodiments, the antibody or antigen-binding portion thereof further comprises an immunoglobulin (Ig) G, IgA, IgM, IgE, or IgD. In some embodiments, the antibody or antigen-binding portion thereof further comprises an IgG1, IgG2, IgG3, or IgG4. In some embodiments, the antibody or antigen -binding portion thereof further comprises a human IgG 1, IgG2, IgG3, or IgG4 In some embodiments, the antibody or antigen-binding portion thereof further comprises an IgG4. In some embodiments, the antibody or antigen-binding portion thereof further comprises a human IgG4. In some embodiments, the CD19 binding moiety, the CD3 binding moiety, or the CD20 binding moiety comprises a fragment antigen -binding (Fab) region, a Fab’, a F(ab’)z, or single chain variable fragment (scFv). In some embodiments, the CD 19 binding moiety, the CD3 binding moiety, or the CD20 binding moiety comprises a Fab region. In some embodiments, the CD 19 binding moiety, the CD3 binding moiety, and the CD20 binding moiety each comprises a Fab region. In some embodiments, HC1, HC2, LC1, LC2 and LC3 comprise domains operably linked, from the amino terminus to the carboxyl terminus, in the following formats: (a) CD19VH-Cβ.CD3VL-Cα-Fc, CD20VH-CH1-Fc, CD19VL-Cα, CD3VH-Cβ, and CD20VL-CL, respectively; (b) CD19VL-Cα-CD3VH-Cβ-Fc, CD20VH-CH1-Fc, CD19VH-Cβ, CD3VL-Cα, and CD20VL-CL, respectively; (c) CD3VH-Cβ-CD19VL-Cα-Fc, CD20VH-CH1-Fc, CD3VL-Cα, CD19VH-Cβ, and CD20VL-CL, respectively; or (d) CD3VL-Cα-CD19VH-Cβ-Fc, CD20VH-CH1-Fc, CD3VH-Cβ, CD19VL-Cα, and CD20VL-CL, respectively. In some embodiments, HC1, HC2, LC1, LC2 and LC3 comprise domains operably linked, from the amino terminus to the carboxyl terminus, in the following formats: CD19VH-Cβ.CD3VL-Cα-Fc, CD20VH-CH1-Fc, CD19VL-Cα, CD3VH-Cβ, and CD20VL-CL, respectively. In some embodiments, CD19VH-Cp is covalently linked to CD3VL-Ca-Fc directly or via a peptide linker; CD19VL-C, is covalently linked to CD3VH-Cp-Fc directly or via a peptide linker; CD3VH-Cp is covalently linked to CDI9VL-Ca-Fc directlyWSGR Docket No. 69143-718.601or via a peptide linker; or CD3VL-Cais covalently linked to CD19VH-Cp-Fc directly or via a peptide linker. In some embodiments, CD19VH-Cp is covalently linked to CD3VL-Ca-Fc directly. In some embodiments, CD19VH-Cp is covalently linked to CD3 VL-Ca-Fc via the peptide linker. In some embodiments, the peptide linker comprises 1 to 40 amino acids in length. In some embodiments, the peptide linker comprises glycine (G) and serine (S). In some embodiments, the peptide linker comprises a glycine (G) and serine (S) linker comprising (GS)n (SEQ ID NO: 46), (GGS)n (SEQ ID NO: 47), (GGGS)n (SEQ ID NO: 48), (GGGGS)n (SEQ ID NO: 49), (GGSG)n (SEQ ID NO: 50), (GGGSS)n (SEQ ID NO: 51), wherein n is an integer of 1-9. In some embodiments, the peptide linker comprises SEQ ID NO: 34. In some embodiments, CDI9VH-Cp is covalently linked to CD3VL-Ca-Fc via the peptide linker comprising SEQ ID NO: 34. In some embodiments, CD19VH-Cβ.CD3VL-Cα is covalently linked to the Fc region directly, via a hinge region, or via a E / K coil linker; CD20VH-CH1 is covalently linked to the Fc region directly, via a hinge region, or via a E / K coil linker; CD19VL-Cα-CD3VH-Cβ is covalently linked to the Fc region directly, via a hinge region, or via a E / K coil linker; CD3VH-Cβ-CD19VL-Cα is covalently linked to the Fc region directly, via a hinge region, or via a E / K coil linker; or CD3VL-Cα-CD19VH-Cβ is covalently linked to the Fc region directly, via a hinge region, or via a E / K coil linker. In some embodiments, CD19VH-Cβ.CD3VL-Cα is covalently linked to the Fc region via the hinge region or via a E / K coil linker. In some embodiments, CD20VH-CHI is covalently linked to the Fc region via the hinge region or via a E / K coil linker. In some embodiments, CD19VH-Cβ.CD3VL-Cα is covalently linked to the Fc region via the hinge region or via a E / K coil linker; and CD20VH-CH1 is covalently linked to the Fc region via the hinge region or via a E / K coil linker. In some embodiments, the hinge region comprises SEQ ID NO: 33. In some embodiments, CD19VH-Cβ.CD3VL-Cα is covalently linked to the Fc region via the hinge region comprising SEQ ID NO: 33. In some embodiments, CD20VH-CH1 is covalently linked to the Fc region via the hinge region comprising SEQ ID NO: 33. In some embodiments, CD19VH-Cβ.CD3VL-Cα is covalently linked to the Fc region via the hinge region comprising SEQ ID NO: 33; and CD20VH-CH1 is covalently linked to the Fc region via the hinge region comprising SEQ ID NO: 33. In some embodiments, CD19VH-Cβ associates with CD19VL-Cα to form the CD19 binding moiety; CD3VL-Cα associates with CD3VH-Cβ to form the CD3 binding moiety;CD20VH-CH1 associates with CD20VL-CL to form the CD20 binding moiety; CD19VL-Cα associates with CD19VH-Cβ to form the CD19 binding moiety; or CD3VH-Cβ associates with CD3VL-Cα to form the CD3 binding moiety. In some embodiments, CD19VH-Cβ associates with CD19VL-Cα to form the CD19 binding moiety; CD3VL-Cα associates with CD3VH-Cβ to form the CD3 binding moiety; and CD20VH-CH1 associates with CD20VL-CL to form the CD20 binding moiety. In some embodiments, Cα and Cβ associate to form a dimer via a bond or an interaction between Cα and Cβ. In some embodiments, Cα or Cβ comprises an amino acid modification that results in a disulfide bond formed between Caand Cp, wherein the disulfide bond improves the stability of the interface between Cα and Cβ. In some embodiments, the Fc region of the antibody or antigen-binding portion thereof comprises a first amino acid mutation that reduces or eliminates antibody-dependent cellular cytotoxicity (ADCC), antibodydependent cellular phagocytosis (ADCP), complement -dependent cytotoxicity (CDC) or binding of the antibody or antigen-binding portion thereof to a Fc-gamma receptor (FcyR). In some embodiments, theWSGR Docket No. 69143-718.601first amino acid mutation comprises a substitution of phenylalanine (F) with alanine (A) at amino acid 234 according to the EU numbering (F234A). In some embodiments, the first amino acid mutation comprises a substitution of leucine (L) with alanine (A) at amino acid 235 according to the EU numbering (L235A). In some embodiments, the first amino acid mutation comprises F234A and L235A, In some embodiments, the Fc region of the first heavy chain (HCl) comprises the first amino acid mutation comprising F234A and L235A. In some embodiments, the Fc region of the second heavy chain (HC2) comprises the first amino acid mutation comprising F234A and L235A. In some embodiments, tire Fc region of the first heavy chain (HCl) comprises the first amino acid mutation comprising F234A and L235A; and the Fc region of the second heavy chain (HC2) comprises tire first amino acid mutation comprising F234A and L235A. In some embodiments, the Fc region of the first heavy chain (HCl) or second heavy chain (HC2) comprises a second amino acid mutation that results in knob-into-hole substitution in the first heavy chain (HCl) or second heavy chain (HC2). In some embodiments, the second amino acid mutation of the Fc region comprises: (a) a substitution of serine (S) with cysteine (C) at amino acid residue 354 according to the EU numbering (S354C); (b) a substitution of threonine (T) with tryptophan (W) at amino acid residue 366 according to the EU numbering (T366W); (c) a substitution of tyrosine (Y) with cysteine (C) at amino acid residue 349 according to the EU numbering (Y349C); (d) a substitution of threonine (T) with serine (S) at amino acid residue 366 according to the EU numbering (T366S); (e) a substitution of leucine (L) with alanine (A) at amino acid residue 368 according to the EU numbering (L368A); or (f) a substitution of tyrosine (Y) with valine (V) at amino acid residue 407 according to the EU numbering (Y 407V). In some embodiments, the Fc region of the first heavy chain (HCl) comprises the second amino acid mutation comprising S354C or T366W; and the Fc region of the second heavy chain (HC2) comprises the second amino acid mutation comprising Y349C, T366S, L368A, or Y407V. In some embodiments, the Fc region of the first heavy chain (HCl) comprises the second amino acid mutation comprising Y349C, T366S, L368A, or Y407 V; and the Fc region of the second heavy chain (HC2) comprises the second amino acid mutation comprising S354C or T366W. In some embodiments, tire Fc region of the first heavy chain (HCl) comprises the second amino acid mutation comprising S354C and T366W; and the Fc region of the second heavy chain (HC2) comprises the second amino acid mutation comprising Y349C, T366S, L368A, and Y407V. In some embodiments, tire Fc region of the first heavy chain (HCl) comprises the second ammo acid mutation comprising Y349C, T366S, L368A, and Y407V; and the Fc region of the second heavy chain (HC2) comprises the second amino acid mutation comprising S354C and T366W. In some embodiments, tlie Fc region of the first heavy chain (HCl) comprises the first amino acid mutation comprising F234A and L235A and the second amino acid mutation comprising S354C and T366W; and the Fc region of the second heavy chain (HC2) comprises the first amino acid mutation comprising F234A and L235A and the second amino acid mutation comprising Y349C, T366S, L368A, and Y407V. In some embodiments, the Fc region of the first heavy chain (HCl) comprises the first amino acid mutation comprising F234A and L235A and the second amino acid mutation comprising Y349C, T366S, L368A, and Y407V; and the Fc region of the second heavy chain (HC2) comprises the first amino acid mutation comprising F234A and L235 A and the second amino acid mutation comprising S354C and T366W. In some embodiments, the Fc region of the first heavy chain (HCl) or second heavy chain (HC2) comprisesWSGR Docket No. 69143-718.601a third amino acid mutation comprising: (a) a substitution of serine (S) with proline (P) at amino acid residue 228 according to the EU numbering (S228P); (b) a substitution of methionine (M) with tyrosine (Y) at amino acid residue 252 according to the EU numbering (M252Y): (c) a substitution of serine (S) with threonine (T) at amino acid residue 254 according to the EU numbering (S254T); or (d) a substitution of threonine (T) with glutamic acid (E) at amino acid residue 256 according to the EU numbering (T256E). In some embodiments, the Fc region of the first heavy chain (HC1) comprises a third amino acid mutation comprising S228P, M252Y, S254T, or T256E. In some embodiments, the Fc region of the second heavy chain (HC1) comprises a third ammo acid mutation comprising S228P, M252Y, S254T, or T256E. In some embodiments, the Fc region of the first heavy chain (HC1) comprises an amino acid sequence with at least 90% sequence identity to SEQ ID NO: 32; or the Fc region of the second heavy chain (HC2) comprises an amino acid sequence with at least 90% sequence identity to SEQ ID NO: 35. In some embodiments, the Fc region of the first heavy chain (HC1) comprises an amino acid sequence with at least 90% sequence identity to SEQ ID NO: 32; and the Fc region of the second heavy chain (HC2) comprises an amino acid sequence with at least 90% sequence identity to SEQ ID NO: 35. In some embodiments, (a)the Fc region of the first heavy chain (HC1) comprises an amino acid sequence with at least 95% sequence identity to SEQ ID NO: 32; or the Fc region of the second heavy chain (HC2) comprises an amino acid sequence with at least 95% sequence identity to SEQ ID NO: 35. In some embodiments, the Fc region of the first heavy chain (HC1) comprises an amino acid sequence with at least 95% sequence identity to SEQ ID NO: 32; and the Fc region of the second heavy chain (HC2) comprises an amino acid sequence with at least 95% sequence identity to SEQ ID NO: 35, In some embodiments, the Fc region of the first heavy chain (HC1) comprises an amino acid sequence with at least 99% sequence identity to SEQ ID NO: 32; or the Fc region of the second heavy chain (IIC2) comprises an amino acid sequence with at least 99% sequence identity to SEQ ID NO: 35. In some embodiments, the Fc region of the first heavy chain (HC 1) comprises an amino acid sequence with at least 99% sequence identity to SEQ ID NO: 32; and the Fc region of the second heavy chain (HC2) comprises an amino acid sequence with at least 99% sequence identity to SEQ ID NO: 35. In some embodiments, the Fc region of the first heavy¬ chain (HC1) comprises the amino acid sequence of SEQ ID NO: 32; or the Fc region of the second heavychain (HC2) comprises the amino acid sequence of SEQ ID NO: 35. In some embodiments, the Fc region of the first heavy chain (HC1) comprises the ammo acid sequence of SEQ ID NO: 32; and the Fc region of the second heavy chain (HC2) comprises the amino acid sequence of SEQ ID NO: 35. In some embodiments, HC1 comprises an amino acid sequence with at least 90% sequence identity to SEQ ID NO: 25; HC2 comprises an amino acid sequence with at least 90% sequence identity to SEQ ID NO: 26; LC1 comprises an amino acid sequence with at least 90% sequence identity to SEQ ID NO: 27; LC2 comprises an amino acid sequence with at least 90% sequence identity to SEQ ID NO: 28; or LC3 comprises an amino acid sequence with at least 90% sequence identity to SEQ ID NO: 29. In some embodiments, HC1 comprises an amino acid sequence with at least 90% sequence identity to SEQ ID NO: 25; HC2 comprises an amino acid sequence with at least 90% sequence identity to SEQ ID NO: 26; LC1 comprises an amino acid sequence with at least 90% sequence identity to SEQ ID NO: 27; LC2 comprises an amino acid sequence with at least 90% sequence identity to SEQ ID NO: 28; and LC3WSGR Docket No. 69143-718.601comprises an amino acid sequence with at least 90% sequence identity to SEQ ID NO: 29. In some embodiments, HC1 comprises an amino acid sequence with at least 95% sequence identity to SEQ ID NO: 25; HC2 comprises an amino acid sequence with at least 95% sequence identity to SEQ ID NO: 26; LC1 comprises an amino acid sequence with at least 95% sequence identity to SEQ ID NO: 27; LC2 comprises an amino acid sequence with at least 95% sequence identity to SEQ ID NO: 28; or LC3 comprises an amino acid sequence with at least 95% sequence identity to SEQ ID NO: 29. In some embodiments, HC1 comprises an amino acid sequence with at least 95% sequence identity to SEQ ID NO: 25; HC2 comprises an ammo acid sequence with at least 95% sequence identity to SEQ ID NO: 26; LC1 comprises an amino acid sequence with at least 95% sequence identity to SEQ ID NO: 27; LC2 comprises an amino acid sequence with at least 95% sequence identity to SEQ ID NO: 28; and LC3 comprises an amino acid sequence with at least 95% sequence identity to SEQ ID NO: 29. In some embodiments, HC1 comprises an amino acid sequence with at least 99% sequence identity to SEQ ID NO: 25; HC2 comprises an amino acid sequence with at least 99% sequence identity to SEQ ID NO: 26; LC1 comprises an amino acid sequence with at least 99% sequence identity to SEQ ID NO: 27; LC2 comprises an amino acid sequence with at least 99% sequence identity to SEQ ID NO: 28; or LC3 comprises an amino acid sequence with at least 99% sequence identity to SEQ ID NO: 29. In some embodiments, HC1 comprises an amino acid sequence with at least 99% sequence identity to SEQ ID NO: 25; HC2 comprises an amino acid sequence with at least 99% sequence identity to SEQ ID NO: 26; LC1 comprises an amino acid sequence with at least 99% sequence identity to SEQ ID NO: 27; LC2 comprises an amino acid sequence with at least 99% sequence identity to SEQ ID NO: 28; and LC3 comprises an amino acid sequence with at least 99% sequence identity to SEQ ID NO: 29. In some embodiments, HC1 comprises the amino acid sequence of SEQ ID NO: 25; HC2 comprises the amino acid sequence of SEQ ID NO: 26; LC1 comprises the amino acid sequence of SEQ ID NO: 27; LC2 comprises the amino acid sequence of SEQ ID NO: 28; or LC3 comprises the amino acid sequence of SEQ ID NO: 29. In some embodiments, HC1 comprises the amino acid sequence of SEQ ID NO: 25; HC2 comprises the amino acid sequence of SEQ ID NO: 26; LC1 comprises the amino acid sequence of SEQ ID NO: 27; LC2 comprises the amino acid sequence of SEQ ID NO: 28; and LC3 comprises the amino acid sequence of SEQ ID NO: 29. In some embodiments, the antibody or antigen-binding portion thereof further comprises HC1, HC2, LC1, LC2, and LC3, wherein: (a) HC1 comprises the amino acid sequence of SEQ ID NO: 25; (b) HC2 comprises the amino acid sequence of SEQ ID NO: 26; (c) LC1 comprises the amino acid sequence of SEQ ID NO: 27; (d) LC2 comprises the amino acid sequence of SEQ ID NO: 28; and (e) LC3 comprises the amino acid sequence of SEQ ID NO: 29.INCORPORATION BY REFERENCE

[0007] All publications, patents, and patent applications mentioned in this specification are herein incorporated by reference in their entireties to the same extent as if each individual publication, patent, or patent application was specifically and individually indicated to be incorporated by reference.WSGR Docket No. 69143-718.601BRIEF DESCRIPTION OF THE DRAWINGS

[0008] The novel features of the disclosure are set forth with particularity in the appended claims. A better understanding of the features and advantages of the present disclosure will be obtained by reference to the following detailed description that sets forth illustrative embodiments, in which the principles of the disclosure are utilized, and the accompanying drawings (also “Figure” and “FIG.” herein), of which:

[0009] Fig. 1 shows representative dose-response curves of autologous B cell depletion in peripheral blood mononuclear cells (PBMCs) from a single healthy volunteer (HV) donor with an ECso of 1.37 ng / mL. Circle denotes MsAb. Diamond denotes isotype.

[0010] Fig. 2 shows representative dose-response curves of autologous B cell depletion in PBMCs from a single donor with rheumatoid arthritis (RA) with an ECso of 1,62 ng / m L. Circle denotes MsAb.Diamond denotes isotype.

[0011] Fig. 3 shows representative dose-response curves of autologous B cell depletion in PBMCs from a single donor with systemic lupus erythematosus (SLE) with an EC50 of 1.27 ng / mL. Circle denotes MsAb. Diamond denotes isotype.

[0012] Fig. 4A and Fig. 4B show representative dose-response curves of T cell activation marker, CD69 upregulation in PBMCs from a single HV donor. Fig. 4A illustrates CD69 upregulation on CD4+cells with EC50of 2.69 ng / mL. Fig. 4B illustrates CD69 upregulation on CD8+cells with EC50of 3.66 ng / mL. Circle denotes MsAb. Diamond denotes isotype.

[0013] Fig. 5A and Fig. 5B show representative dose-response curves of T cell activation marker, CD69 upregulation in PBMCs from a single RA donor. Fig. 5A illustrates CD69 upregulation on CD4+cells with EC50 of 5.91 ng / mL. Fig. 5B illustrates CD69 upregulation on CD8+cells with EC50of 5.40 ng / mL. Circle denotes MsAb. Diamond denotes isotype.

[0014] Fig. 6A and Fig. 6B show representative dose-response curves of T cell activation marker, CD69 upregulation in PBMCs from a single SLE donor. Fig. 6A illustrates CD69 upregulation on CD4+cells with EC50of 8.18 ng / mL. Fig. 6B illustrates CD69 upregulation on CD8+cells with EC50of 3.56 ng / mL. Triangle denotes MsAb-TA-40. Diamond denotes isotype.

[0015] Figs. 7A-D show representative dose-response curves of cytokine release in PBMCs from a single HV donor. Fig. 7A shows induced IFN-γ release at EC50of 18.30 ng / mL (circle denotes MsAb-TA-40-IFN-y, and diamond denotes Isotype-IFN-γ). Fig. 7B shows induced IL-2 release at EC50of 51.06 ng / mL (circle denotes MsAb-TA-40-IL-2, and diamond denotes Isotype -IL-2). Fig. 7C shows induced IL-6 release at EC50of 16.9 ng / mL (circle denotes MsAb-TA-40-IL-6, and diamond denotes Isotype-IL-6). Fig.7D shows induced TNF-α release at EC50of 22.10 ng / mL (circle denotes MsAb-TA-40-TNF-α, and diamond denotes Isotype-TNF-α).

[0016] Figs. 8A-D show representative dose-response curves of cytokine release in PBMCs from a single RA donor. Fig. 8A shows induced IFN-γ release at EC50of 16.03 ng / mL (square denotes MsAb-TA-40-IFN-y, and diamond denotes Isotype-IFN-γ). Fig. 8B shows induced IL-2 release at EC50of 54.42 ng / mL (square denotes MsAb-TA-40-IL-2, and diamond denotes Isotype-IL-2). Fig. 8C shows induced IL-6WSGR Docket No. 69143-718.601release at EC50 of 10.88 ng / mL (square denotes MsAb-TA-40-IL-6, and diamond denotes Isotype-IL-6).Fig. 8D shows induced TNF-a release at EC50 of 24.45 ng / mL (square denotes MsAb-TA-40-TNF-a, and diamond denotes Isotype-TNF-a).

[0017] Fig. 9A-D show representative dose-response curves of cytokine release in PBMCs from a single SLE donor. Fig. 9A shows induced IFN-γ release at EC50of 12.12 ng / mL (triangle denotes MsAb-TA-40-IFN-γ, and diamond denotes Isotype-IFN-γ). Fig. 9B shows induced IL-2 release at EC50of 16.73 ng / mL (triangle denotes MsAb-TA-40-IL-2, and diamond denotes Isotype-IL-2). Fig. 9C shows induced IL-6 release at EC50of 5.61 ng / mL (triangle denotes MsAb-TA-40-IL-6, and diamond denotes Isotype-IL-6).Fig. 9D shows induced TNF-α release at EC50of 15.94 ng / mL (triangle denotes MsAb-TA-40-TNF-α, and diamond denotes Isotype-TNF-α).

[0018] Fig. 10 shows boxplot of MsAb EC50values for target B cell depletion, CD69 activation on CD4+T or CD8+T cells, and IL-6 release in PBMCs derived from HV, RA, and SLE donors. The box represents the interquartile range (IQR); the line within the box indicates the median. Individual dots represent EC50values from independent donors. Median EC50 values (ng / mL) are indicated above each bar. A two-tailed unpaired Student’s t-test was used to compare the respective EC50 values across HV, RA, and SLE donor groups (n=9). A p-value calculated was > 0.05, indicating no statistically significant differences were observed between any groups.

[0019] Fig. 11 shows representative MsAb dose-response curves of autologous B cell depletion from a single donor Cyno PBMC sample having an EC50 of 0.017 pg / mL. Square denotes isotype, and circle denotes MsAb-TA-40.

[0020] Fig. 12A and Fig. 12B show representative dose-response curves of CD69 upregulation on CD4+T cells and CD8+T cells from a single Cyno donor PBMCs. Fig. 12A illustrates CD69 upregulation on CD4+cells with EC50 of 0.028 pg / mL. Fig. 12B illustrates CD69 upregulation on CD8+cells with EC50 of 0.0075 pg / mL. Square denotes isotype, and circle denotes MsAb-TA-40.

[0021] Fig. 13A and Fig. 13B show representative dose-response curves of CD25 upregulation on CD4+and CD8+T cells from single donor PBMCs. Fig. 13A illustrates CD25 upregulation on CD4 cells with EC50 of 0.206 pg / mL. Fig. 13B illustrates CD25 upregulation on CD8+cells with EC50of 0.097 pg / mL. Square denotes isotype, and circle denotes MsAb-TA-40.

[0022] Figs. 14A-D show representative dose-responses of cytokine release induced by MsAb in a single donor PBMCs. Fig. 14A illustrates induced IFN-y release having an EC50 of 0.145 pg / mL. Fig. 14B illustrates induced IL-2 release having an EC50 of 0.420 pg / mL. Fig. 14C illustrates induced IL-6 release having an EC50 of 0.045 pg / mL. Fig. 14D illustrates induced TNF-a release having an EC50 of 0.064 pg / mL. Square denotes isotype, and circle denotes MsAb-TA-40.

[0023] Fig. 15 shows absolute counts of CD20+B cells in peripheral blood from MsAb-treated cynomolgus monkey as determined by flow cytometry.

[0024] Fig. 16 shows frequency of CD20 positive B cells in lymphoid tissues from MsAb-treated cynomolgus monkey as determined by flow cytometry. Historical controls were results from untreated animals analyzed as part of earlier experiments.WSGR Docket No. 69143-718.601

[0025] Fig. 17 shows photomicrographs of tissue sections of mesenteric lymph nodes from MsAb-treated cynomolgus monkey stained for CD 19, CD20, and CD 138 by immunohistochemistry. Control was a concurrently stained banked tissue specimens from an untreated control animal.DETAILED DESCRIPTION

[0026] This application generally relates to uses of antibodies for treatment of a disease or disorder in a subject in need thereof. Particularly, the application relates to multispecific antibodies or antigen-binding portions thereof that bind to cluster of differentiation 3 (CD3), cluster of differentiation 19 (CD19) and cluster of differentiation 20 (CD20) and their use in treatment of an autoimmune disease or disorder in a subject. Definition

[0027] In order to better understand the disclosure, tire definitions and explanations of the relevant terms are provided as follows.

[0028] Unless otherwise defined herein, scientific and technical terms used in connection with the present disclosure shall have the meanings that are commonly understood by those of ordinary skill in the art. Further, unless otherwise required by context, singular terms shall include pluralities and plural terms shall include the singular. More specifically, as used in this specification and the appended claims, the singular forms “a”, "an" and ‘“the” include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to “‘a protein” includes a plurality of proteins; reference to “a cell” includes mixtures of cells, and tire like. In this application, the use of “or” means “and / or” unless stated otherwise. Furthermore, the use of the term “comprising,” as well as other forms, such as “comprises" and “comprised,” is not limiting. In addition, ranges provided in the specification and appended claims include both end points and all points between the end points.

[0029] The terms “antibody” and “polypeptide complex” can be used interchangeably herein and encompass various antibody structures, including but not limited to monoclonal antibodies, polyclonal antibodies, humanized antibodies, fully human antibodies, chimeric antibodies, multi -specific antibodies and antibody fragments, so long as they exhibit the desired antigen-binding activity. Antibody generally comprises heavy (H) and light (L) polypeptide chains held together by covalent disulfide bonds and non-covalent interactions. Light chains of an antibody may be classified into K and A, light chain. Heavy chains may be classified into p, 8, y, a and e, which define isotypes of an antibody as IgG (e.g,, IgGl, IgG2, IgG3 or IgG4 subtype), IgAl, IgA2, IgD, IgE or IgM, respectively. For a classical antibody, each heavy chain comprises a heavy chain variable region (VH) and a heavy chain constant region (CH), and each light chain comprises a light chain variable region (VL) and a light chain constant region (CL). VH and VL regions can further be divided into hypervanable regions (called complementary’ determining regions (CDR), which are interspaced by relatively conservative regions (called framework region (FR)). Each VH and VL consists of 3 CDRs and 4 FRs in the following order: FR1, CDR1, FR2, CDR2, FR3, CDR3, FR4 from N-terminal to C-terminal. The variable region (VH and VL) of each heavy / light chain pair forms antigen binding sites, respectively, A heavy chain constant region comprises 3 domains (CHI, CH2 and CH3). A light chain constant region comprises a CL domain. When constructing a multispecific (e.g., trispecific or bispecific) antibody, depending on the format, it is not always necessary for the VH region to be in theWSGR Docket No. 69143-718.601heavy chain and the VL region to be in the light chain of the polypeptide complex. As used herein, a heavy chain of the polypeptide complex refers to the Fc comprising chain, a light chain of the polypeptide complex refers to the chain without a Fc domain which is much shorter than tire heavy chain. In some embodiments, the heavy chain comprises a VH of the first antigen -binding moiety and a VL of the second antigen -binding moiety. In some embodiments, the heavy chain comprises a VL of the first antigen¬ binding moiety and a VH of the second antigen-binding moiety.

[0030] The term “antigen-binding portion” or “antigen-binding fragment” of an antibody or polypeptide complex refers to polypeptides comprising fragments of a full-length antibody, which retain the ability of specifically binding to an antigen(s) that the full-length antibody specifically binds to, and / or compete with the full-length antibody for binding to the same antigen(s). Generally, see Fundamental Immunology, Ch. 7 (Paul, W., ed., the second edition, Raven Press, N. Y. (1989), incorporated herein by reference for all purposes. Antigen binding fragments of an antibody may be produced by recombinant DNA techniques or by enzymatic or chemical cleavage of an intact antibody. Under some conditions, antigen binding fragments include Fab, Fab', Fab'-SH, F(ab')2, Fd, Fv, dAb and complementary determining region (CDR) fragments, single chain antibody (e.g., scFv), chimeric antibody, diabody and such polypeptides that comprise at least part of antibody sufficient to confer the specific antigen binding ability’ on the polypeptides. Antigen binding fragments of an antibody may be obtained from a given antibody (e.g., the trispecific anti-CD3 x CD 19 x CD20 antibody provided herein) by conventional techniques known by a person skilled in the art (e.g., recombinant DNA technique or enzymatic or chemical cleavage methods), and may be screened for specificity in the same manner by which intact antibodies are screened,

[0031] The term “antigen-binding moiety” as used herein refers to an antibody fragment formed from a portion of an antibody comprising one or more CDRs, or any other antibody fragment that binds to an antigen but does not comprise an intact native antibody structure. Examples of antigen-binding moiety include, without limitation, a variable domain, a variable region, a diabody, a Fab, a Fab', a F(ab')2, an Fv fragment, a single chain Fv fragment (scFv), a disulfide stabilized Fv fragment (dsFv), a (dsFv)2, a bispecific dsFv (dsFv-dsFv'), a disulfide stabilized diabody (ds diabody), a multispecific antibody, a camelized single domain antibody, a single variable domain (i.e. VHH), a nanobody, a domain antibody, and a bivalent domain antibody. An antigen-binding moiety is capable of binding to the same antigen to which the parent antibody binds. More detailed formats of antigen-binding moiety are described in Spiess el al., (2015) Molecular Immunology 67: 95-106, and Brinkman et al., mAbs, 9(2), pp.182-212 (2017), which are incorporated herein by their entirety. Tire terms “CD3 binding moiety” and “anti-CD3 moiety” and similar terminology have the meaning herein.

[0032] “Allergy” as used herein refers to a state of hypersensitivity caused by exposure to a specific antigen allergen that produces an adverse immunological response such as allergic reaction after exposure.

[0033] “Allergic reaction” as used herein refers to the body’s response to an allergen. The allergic reaction can be localized to one area (skin that came into contact with allergen) or generalized. Allergic reactions may include, but are not limited to, rash, itching, hives, swelling, difficulty breathing, wheezing, angioedema, difficulty swallowing, nasal congestion, runny nose, shortness of breath, nausea, stomach cramps, abdominal pain, vomiting and / or low blood pressure.WSGR Docket No. 69143-718.601

[0034] ‘‘Allergen” as used herein refers an antigenic substance capable of producing immediate type hypersensitivity (allergy). Common allergens include, but are not limited to bacteria, viruses, animal parasites, insects and insect stings, chemicals (latex), dust, dust mites, molds, animal dander, drugs (such as antibiotics, serums, sulfa drags, anti-convulsants, insulin preparations, local anesthetics, iodine, and aspirin), foods (such as milk, chocolate, strawberries, eggs, soy, nuts, fish, shellfish, wheat), perfumes, plants, pollens, and smoke.

[0035] “Alloantibody” as used herein refers to an antibody that is produced by a B cell specific for an alloantigen,

[0036] ‘‘Alloantigen” as used herein refers to an antigen present only in some individuals (such as a particular blood group) of a species and capable of inducing the production of an alloantibody by individuals that lack tire alloantigen.

[0037] “Autoimmunity” or “autoimmune disease or disorder” as used herein, refers broadly to a condition in which a subject experiences cellular, tissue, and / or organ injury resulting from an immunological reaction against its own cells, tissues, or organs.

[0038] “Fab” with regard to an antibody refers to that portion of the antibody consisting of a single light chain (both variable and constant regions) associating to the variable region and first constant region of a single heavy chain by a disulfide bond. In certain embodiments, the constant regions of both the light chain and heavy chain of the Fab may be replaced with TCR constant regions Caand Cp or engineered variants thereof.

[0039] “Fc” (short for fragment, crystallizable) with regard to an antibody refers to that portion of the antibody comprising the second (CH2) and third (CH3) constant regions of a first heavy chain bound to the second and third constant regions of a second heavy chain via disulfide bonding. Fc is a specific dimerization domain. The Fc region as used herein may also comprise part or whole of the hinge region. The Fc region of the antibody is responsible for various effector functions such as ADCC, ADCP and CDC, but generally does not function in antigen binding. The capacity of an tibodies to initiate and regulate effector functions through their Fc domain is a key component of their in vivo protective activity. Although the neutralizing activity of antibodies has been previously considered to be solely the outcome of Fab-antigen interactions, it has become apparent that their in vivo activity is highly dependent on interactions of the IgG Fc domain with its cognate receptors, Fey receptors (FcyRs), expressed on the surface of effector leukocytes.

[0040] The terms “operably link” and “operably linked” refer to a juxtaposition, with or without a spacer or linker, of two or more biological sequences of interest in such a way that they are in a relationship permitting them to function in an intended manner. When used with respect to polypeptides, it is intended to mean that the polypeptide sequences are linked in such a way that permits the linked product to have the intended biological function. For example, an antibody variable region may be operably linked to a constant region so as to provide for a stable product with antigen-binding activity. The term may also be used with respect to polynucleotides. For one instance, when a polynucleotide encoding a polypeptide is operably linked to a regulatory sequence (e.g., promoter, enhancer, silencer sequence, etc.), it is intended to mean that the polynucleotide sequences are linked in such a way that permits regulated expression ofWSGR Docket No. 69143-718.601the polypeptide from the polynucleotide. The term operably linked, when used herein to describe domains linked to form a polypeptide, can be represented by a “-”, and can refer to a direct linkage between domains or linkage via a linker comprising 1-30 amino acids in length, such as a single amino acid or a series of (G4S)n linker, with n=l-5 (1, 2, 3, 4, or 5) (SEQ ID NO: 52),

[0041] The term “humanized antibody”, as used herein, refers to antibodies in which CDR sequences derived from the germline of another mammalian species, such as a rat or mouse, have been grafted onto human framework sequences. Additional framework region modifications may be made within the human framework sequences. The humanized antibody optionally will also comprise at least a portion of an immunoglobulin constant region (Fc), typically that of a human immunoglobulin.

[0042] Tire term “human antibody” or “fully human antibody,” as used herein, is intended to include antibodies having variable regions in which both the framework and CDR regions are derived from human germline immunoglobulin sequences. Furthermore, if the antibody contains a constant region, the constant region also is derived from human germline immunoglobulin sequences.

[0043] The term “CD3 x CD 19 x CD20 antibody” or “anti-CD3 x CD 19 x CD20 antibody” or “multispecific antibody”, as used herein, refers to a multispecific antibody that comprises at least three different antigen-binding moieties, binding specifically to the antigen CD3, CD19 and CD20, respectively.

[0044] The term “cluster of differentiation 3” or “CD3”, as used herein, refers to any native CD3 from any vertebrate source, including mammals such as primates (e.g. humans) and rodents (e.g., mice and rats), unless otherwise indicated, including, for example, CD3s, CD3y, CD35, and CD3q chains. The term encompasses “full-length” unprocessed CD3 (e.g., unprocessed or unmodified CD3E or CD3y), as well as any form of CD3 that results from processing in the cell and naturally occurring variants of CD3, including, for example, splice variants or allelic variants.

[0045] The term “cluster of differentiation 20” or “CD20” as used herein is also called human B- lymphocyte-restricted differentiation antigen (Bp35). It is a hydrophobic transmembrane protein located on pre-B and mature B lymphocytes (Valentine et al. J. Biol. Chem. 264(19): 11282- 11287 (1989); and Einfeld et al. EMBO J. 7(3):711-717 (1988)).

[0046] The term “cluster of differentiation 19” or “CD 19” as used herein is a transmembrane protein that in humans is expressed in all B lineage cells as well as plasmablast and certain plasma cells, CD 19 is a biomarker for normal and neoplastic B cells, as well as follicular dendritic cells. CD19 is involved in establishing intrinsic B cell signaling thresholds through modulating both B cell receptor-dependent and independent signaling. CD 19 functions as the signaling component of a multimolecular complex on the surface of m ature B cells, alongside complement receptor CD21, and the tetraspanin membrane protein CD81 (TAPA-1), as well as CD225. Due to its presence on all B cells, it is abiomarker for B lymphocyte development, lymphoma diagnosis and can be utilized as a target for leukemia immunotherapies.

[0047] The term “isolated,” as used herein, refers to a state obtained from natural state by artificial means. If a certain “isolated” substance or component is present in nature, it is possible because its natural environment changes, or the substance is isolated from natural environment, or both. For example, a certain un-isolated polynucleotide or polypeptide naturally exists in a certain living animal body, and theWSGR Docket No. 69143-718.601same polynucleotide or polypeptide with a high purity isolated from such a natural state is called isolated polynucleotide or polypeptide. The term “isolated” excludes neither the mixed artificial or synthesized substance nor other impure substances that do not affect the activity of the isolated substance.

[0048] The term “vector,” as used herein, refers to a nucleic acid vehicle which can have a polynucleotide inserted therein. When the vector allows for the expression of the protein encoded by the polynucleotide inserted therein, the vector is called an expression vector. The vector can have the carried genetic material elements expressed in a host cell by transformation, transduction, or transfection into tire host cell. Vectors are well known by a person skilled in the art, including, but not limited to plasmids, phages, cosmids, artificial chromosome such as yeast artificial chromosome (YAC), bacterial artificial chromosome (BAC) or Pl -derived artificial chromosome (PAC); phage such as λ phage or M13 phage and animal virus. The animal viruses that can be used as vectors, include, but are not limited to, retrovirus (including lentivirus), adenovirus, adeno-associated virus, herpes virus (such as herpes simplex virus), pox virus, baculovirus, papillomavirus, papova virus (such as SV40). A vector may comprise multiple elements for controlling expression, including, but not limited to, a promoter sequence, a transcription initiation sequence, an enhancer sequence, a selection element and a reporter gene. In addition, a vector may comprise origin of replication.

[0049] The term “host cell,” as used herein, refers to a cellular system which can be engineered to generate proteins, protein fragments, or peptides of interest. Host cells include, without limitation, cultured cells, e.g., mammalian cultured cells derived from rodents (rats, mice, guinea pigs, or hamsters) such as CHO, BHK, NSO, SP2 / 0, YB2 / 0; or human tissues or hybridoma cells, yeast cells, and insect cells, and cells comprised within a transgenic animal or cultured tissue. The term encompasses not only the particular subject cell but also the progeny of such a cell. Because certain modifications may occur in succeeding generations due to either mutation or environmental influences, such progeny may not be identical to the parent cell, but are still included within the scope of the term “host cell.”

[0050] The term “identity,” as used herein, refers to a relationship between the sequences of two or more polypeptide molecules or two or more nucleic acid molecules, as determined by aligning and comparing the sequences. “Percent identity” means the percent of identical residues between the amino acids or nucleotides in the compared molecules and is calculated based on the size of the smallest of the molecules being compared. For these calculations, gaps in alignments (if any) are preferably addressed by a particular mathematical model or computer program (i.e., an “algorithm”). Methods that can be used to calculate the identity of the aligned nucleic acids or polypeptides include those described in Computational Molecular Biology, (Lesk, A. M., ed.), 1988, New York: Oxford University Press;Biocomputing Informatics and Genome Projects, (Smith, D, W., ed.), 1993, New York: Academic Press; Computer Analysis of Sequence Data, Part I, (Griffin, A. M., and Griffin, H. G., eds.), 1994, New Jersey: Humana Press; von Heinje, G., 1987, Sequence Analysis in Molecular Biology, New York: Academic Press; Sequence Analysis Primer, (Gribskov, M. and Devereux, J., eds.), 1991, New York: M. Stockton Press; and Carillo et al, 1988, SIAM J. Applied Math. 48:1073.

[0051] Unless indicated otherwise, the “percent sequence identity” between a reference amino acid sequence and a query amino sequence (i.e., the amino sequence being analyzed to determine whether it isWSGR Docket No. 69143-718.601within a particular percent sequence identity with the reference amino acid sequence) is determined by optimally aligning the sequences using the Needleman-Wunsch alignment algorithm with a gap existence penalty of 11 and a gap extension penalty of 1 and comparing the sequences. The number of exact matches, divided by the total number of positions in the alignment (which corresponds with the number of amino acids in the reference sequence plus any gaps in the reference sequence when aligned with the query sequence) is determined and expressed as a percentage. This is the percent sequence identity between the query amino acid sequence and the reference amino acid sequence (i.e., percent sequence identity = (# of exact matches / (total # of positions in alignment)* 100). An alignment using the Needleman-Wunsch alignment algorithm (with a gap existence penalty of 11 and a gap extension penalty of 1) can be generated using the “Global Align” BLAST program available at blast.ncbi.nlm.nih.gov / Blast.cgi.

[0052] Unless indicated otherwise, the “percent sequence identity” between a reference nucleic acid sequence and a query nucleic acid sequence (i.e., the nucleic acid sequence being analyzed to determine whether it is within a particular percent sequence identity with the reference nucleic acid sequence) is determined by optimally aligning the sequences using the Needleman-Wunsch alignment algorithm (with match / mismatch scores of 2,-3, a gap existence penalty’ of 5, and a gap extension penalty of 2) and comparing the aligned nucleic acids. The number of exact matches divided by the total number of nucleotides in the alignment (which corresponds with the number of nucleotides in the reference sequence plus any gaps in the reference sequence when aligned with the query sequence) is determined and expressed as a percentage. This is the percent sequence identity between the query’ nucleic acid sequence and the reference nucleic acid sequence (i.e., percent sequence identity = (# of exact matches) / (total # of nucleotides in the alignment)* 100). An alignment using the Needleman-Wunsch alignment algorithm (with match / mismatch scores of 2,-3, a gap existence penalty of 5, and a gap extension penalty of 2) can be generated using the “Global Align” BLAST program available at blast.ncbi.nlm.nih.gov / Blast.cgi.

[0053] The term “transfection,” as used herein, refers to the process by which nucleic acids are introduced into eukaryotic cells, particularly mammalian cells. Protocols and techniques for transfection include but not limited to lipid transfection and chemical and physical methods such as electroporation. A number of transfection techniques are well known in the art and are disclosed herein. See, e.g., Graham et al., 1973, Virology 52:456; Sambrook et al., 2001, Molecular Cloning: A Laboratory Manual, supra; Davis et al., 1986, Basic Methods in Molecular Biology, Elsevier; Chu et al, 1981, Gene 13: 197. In a specific embodiment of the invention, human CD3 gene was transfected into CHO cells.

[0054] The terms “subject” and “patient” are used interchangeably and include mammals such as humans and non-human primates, as well as rabbits, rats, mice, goats, pigs, and other mammalian species. The term does not necessarily indicate that the subject has been diagnosed with a particular disease, but typically refers to an individual under medical supervision.

[0055] lire term “prevent,” “prevention” or “preventing,” as used herein, with reference to a certain disease condition in a mammal, refers to preventing or delaying the onset of the disease, or preventing the manifestation of clinical or subclinical symptoms thereof.WSGR Docket No. 69143-718.601

[0056] The term “treatment,” “treating” or “treated,” as used herein in the context of treating a condition, pertains generally to treatment and therapy, whether of a human or an animal, in which some desired therapeutic effect is achieved, for example, the inhibition of the progress of the condition, and includes a reduction in the rate of progress, a halt in the rate of progress, regression of the condition, amelioration of the condition, and cure of the condition.

[0057] The term “an effective amount,” as used herein, pertains to that amount of an active compound, or a material, composition or dosage form comprising an active compound, which is effective for producing some desired therapeutic effect, commensurate with a reasonable benefit / risk ratio, when administered in accordance with a desired treatment regimen. For instance, the “an effective amount,” when used in connection with treatment of a disease or condition, refers to an antibody or antigen-binding portion thereof in an amount or concentration effective to treat the said disease or condition.

[0058] The term “pharmaceutically acceptable,” as used herein, means that the vehicle, diluent, excipient and / or salts thereof, are chemically and / or physically is compatible with other ingredients in the formulation, and the physiologically compatible with the recipient.

[0059] As used herein, the term “a pharmaceutically acceptable carrier and / or excipient” refers to a carrier and / or excipient pharmacologically and / or physiologically compatible with a subject and an active agent, which is well known in the art (see, e.g., Remington's Pharmaceutical Sciences. Edited by Gennaro AR, 19th ed. Pennsylvania: Mack Publishing Company, 1995), and includes, but is not limited to pH adjuster, surfactant, adjuvant and ionic strength enhancer. For example, the pH adjuster includes, but is not limited to, phosphate buffer; the surfactant includes, but is not limited to, cationic, anionic, or nonionic surfactant, e.g., Tween-80; the ionic strength enhancer includes, but is not limited to, sodium chloride.

[0060] The “EU numbering system” or “EU index” is generally used when referring to a residue in an immunoglobulin heavy chain constant region (e.g., the EU index reported in Kabat et al., supra), lire “EU numbering as in Kabat” or “EU index as in Kabat” refers to the residue numbering of the human IgGl EU antibody. Unless stated otherwise herein, references to residue numbers in the constant domain of antibodies means residue numbering by the EU numbering system.Methods of Treatment

[0061] In one aspect, disclosed herein, is a method for treating an autoimmune disease or disorder in a subject, comprising administering to the subject a therapeutically effective amount of (i) an antibody or antigen-binding portion thereof comprising a CD 19 binding moiety, a CD3 binding moiety and a CD20 binding moiety, or (i i) one or more polynucleotide encoding the antibody or antigen-binding portion thereof; wherein (a) the CD 19 binding moiety comprises a heavy chain complementarity determining region (HCDR) 1, a HCDR2 and a HCDR3 comprising the amino acid sequences of SEQ ID NOs: 1, 2 and 3, respectively, and a light chain complementarity determining region (LCDR) 1, a LCDR2 and a LCDR3 comprising the amino acid sequences of SEQ ID NOs: 4, 5 and 6, respectively; (b) the CD3 binding moiety comprises a HCDR1, a HCDR2 and a HCDR3 comprising the amino acid sequences of SEQ ID NOs: 7, 8 and 9, respectively, and a LCDR1, a LCDR2 and a LCDR3 comprising the amino acidWSGR Docket No. 69143-718.601sequences of SEQ ID NOs: 10, 11 and 12, respectively; and (c) the CD20 binding moiety comprises a HCDR1, a HCDR2 and a HCDR3 comprising the amino acid sequences of SEQ ID NOs: 13, 14 and 15, respectively, and a LCDR1, a LCDR2 and a LCDR3 comprising the amino acid sequences of SEQ ID NOs: 16, 17 and 18, respectively.

[0062] In some cases, the autoimmune disease or disorder comprises an autoantibody-driven disease. In some cases, the autoimmune disease or disorder comprises a disease mediated by an autoantibody, in some cases, the autoimmune disease or disorder comprises a disease mediated by a B cell, a plasmablast, or a plasma cell. In some cases, the autoimmune disease or disorder comprises a disease mediated by a B cell. In some cases, the autoimmune disease or disorder comprises a disease mediated by a plasmablast. In some cases, the autoimmune disease or disorder comprises a disease mediated by a plasma cell. In some cases, the autoimmune disease or disorder comprises a disease mediated by a B cell, a plasmablast, and a plasma cell. In some cases, the autoimmune disease or disorder comprises a disease mediated by a mature B cell, a memory B cell, or an activated B cell. In some cases, the autoimmune disease or disorder comprises a disease mediated by a mature B cell. In some cases, the autoimmune disease or disorder comprises a disease mediated by a memory B cell. In some cases, the autoimmune disease or disorder comprises a disease mediated by an activated B cell. In some cases, the autoimmune disease or disorder comprises a disease mediated by a mature B cell, a memory B cell, and an activated B cell.

[0063] In some cases, the autoimmune disease or disorder may include allergy, antibody-mediated rejection, alloantibodies, a disease related to or mediated by an alloantibody, amyloidosis, anti -glomerular basement membrane (GBM) (Goodpasture Syndrome), anti-N-methyl-D-aspartate receptor (NMD A) encephalitis (anti-NMDA-R Encephalitis), anti-neutrophil cytoplasmic autoantibody-associated vasculitis (ANCA vasculitis), antiphospholipid antibody syndrome, antisynthetase Syndrome, atopic dermatitis, autoimmune hepatitis, autoimmune necrotizing myopathy, Behcet’s disease, Bullous Pemphigoid, Celiac disease, Chronic Inflammatory Demyelinating Polyneuropathy (CIDP), Crohn’s disease, dilated cardiomyopathy, Graves, Guillain Barre Syndrome, Hidradenitis Suppurativa, IgA Nephropathy, Immunoglobulin G4-related disease (IgG4-RD), immune vasculitis (IgA), immune thrombocytopenia (ITP), Long COVID, Lupus Nephritis, Membranous Nephropathy, microscopic polyangiitis, multiple sclerosis (MS) - primary progressive multiple sclerosis (MS-PPMS), multiple sclerosis (MS) -relapsingremitting multiple sclerosis (MS-RRMS), Myasthenia Gravis, myositis-dermatomyositis, myositis¬ inclusion body, myositis-polymyositis, myositis- immune-mediated necrotizing myositis, neuromyelitis optica spectrum disorder (NMOSD), Pemphigus Vulgaris, polyneuropathy, organomegaly, endocrinopathy, M-protein and skin changes (POEMS) syndrome, Polyarteritis Nodosa, Postural Orthostatic Tachycardia Syndrome (POTS), Primary Biliary Cirrhosis. Primary Sclerosing Cholangitis, Psoriasis, Psoriatic Arthritis, Raynaud’s Syndrome, Reactive Arthritis, rheumatoid arthritis, scleroderma or systemic sclerosis, Sjogren’s Syndrome, Stiff Person Syndrome, Type 1 diabetes, Thyroid eye disease, tumor progression, or ulcerative colitis. In some embodiments, the autoimmune disease or disorder comprises allergy. In some embodiments, the autoimmune disease or disorder comprises antibody-mediated rejection. In some embodiments, the autoimmune disease or disorder comprises alloantibodies. in some embodiments, the autoimmune disease or disorder comprises a disease related to or mediated byWSGR Docket No. 69143-718.601an alloantibody. In some embodiments, the autoimmune disease or disorder comprises amyloidosis. In some embodiments, the autoimmune disease or disorder comprises anti-GBM (Goodpasture Syndrome). In some embodiments, the autoimmune disease or disorder comprises anti-NMDA-R Encephalitis. In some embodiments, the autoimmune disease or disorder comprises ANCA vasculitis. In some embodiments, the autoimmune disease or disorder comprises antiphospholipid antibody syndrome. In some embodiments, the autoimmune disease or disorder comprises antisynthetase Syndrome. In some embodiments, the autoimmune disease or disorder comprises atopic dermatitis. In some embodiments, the autoimmune disease or disorder comprises autoimmune hepatitis. In some embodiments, the autoimmune disease or disorder comprises autoimmune necrotizing myopathy. In some embodiments, the autoimmune disease or disorder comprises Behcet’s disease. In some embodiments, the autoimmune disease or disorder comprises Bullous Pemphigoid. In some embodiments, the autoimmune disease or disorder comprises Celiac disease. In some embodiments, the autoimmune disease or disorder comprises CIDP. In some embodiments, the autoimmune disease or disorder comprises Crohn’s disease. In some embodiments, the autoimmune disease or disorder comprises dilated cardiomyopathy. In some embodiments, the autoimmune disease or disorder comprises Graves. In some embodiments, the autoimmune disease or disorder comprises Guillain Barre Syndrome. In some embodiments, the autoimmune disease or disorder comprises Hidradenitis Suppurativa. In some embodiments, the autoimmune disease or disorder comprises IgA Nephropathy. In some embodiments, the autoimmune disease or disorder comprises IgG4-RD. In some embodiments, the autoimmune disease or disorder comprises immune vasculitis (IgA), In some embodiments, the autoimmune disease or disorder comprises ITP. In some embodiments, the autoimmune disease or disorder comprises Long COVID. In some embodiments, the autoimmune disease or disorder comprises Lupus Nephritis. In some embodiments, the autoimmune disease or disorder comprises Membranous Nephropathy. In some embodiments, the autoimmune disease or disorder comprises microscopic polyangiitis. In some embodiments, the autoimmune disease or disorder comprises MS-PPMS. In some embodiments, the autoimmune disease or disorder comprises MS-RRMS. In some embodiments, the autoimmune disease or disorder comprises Myasthenia Gravis. In some embodiments, the autoimmune disease or disorder comprises myositis-dermatomyositis. In some embodiments, the autoimmune disease or disorder comprises myositis-inclusion body. In some embodiments, the autoimmune disease or disorder comprises myositis-polymyositis. In some embodiments, the autoimmune disease or disorder comprises myositis-immune-mediated necrotizing myositis. In some embodiments, the autoimmune disease or disorder comprises NMOSD. In some embodiments, tire autoimmune disease or disorder comprises Pemphigus Vulgaris. In some embodiments, the autoimmune disease or disorder comprises POEMS syndrome. In some embodiments, the autoimmune disease or disorder comprises POTS. In some embodiments, the autoimmune disease or disorder comprises Polyarteritis Nodosa. In some embodiments, the autoimmune disease or disorder comprises Primary Biliary Cirrhosis. In some embodiments, the autoimmune disease or disorder comprises Primary Sclerosing Cholangitis. In some embodiments, the autoimmune disease or disorder comprises Psoriasis. In some embodiments, the autoimmune disease or disorder comprises Psoriatic Arthritis. In some embodiments, the autoimmune disease or disorder comprises Raynaud’s Syndrome. InWSGR Docket No. 69143-718.601some embodiments, the autoimmune disease or disorder comprises Reactive Arthritis. In some embodiments, the autoimmune disease or disorder comprises rheumatoid arthritis. In some embodiments, the autoimmune disease or disorder comprises scleroderma or systemic sclerosis. In some embodiments, the autoimmune disease or disorder comprises Sjogren’s Syndrome. In some embodiments, the autoimmune disease or disorder comprises Stiff Person Syndrome. In some embodiments, the autoimmune disease or disorder comprises Type 1 diabetes. In some embodiments, the autoimmune disease or disorder comprises Thyroid eye disease. In some embodiments, the autoimmune disease or disorder comprises tumor progression. In some embodiments, the autoimmune disease or disorder comprises ulcerative colitis.

[0064] In some cases, the subject is a human or non-human primate. In some case, the subject is a human and is diagnosed with the autoimmune disease or disorder. In some cases, the subject is a human and is suspected to have the autoimmune disease or disorder.

[0065] In some cases, the therapeutically effective amount of the antibody or antigen-binding portion thereof is calculated based on a biomarker. In some cases, the method further comprises measuring a biomarker in the subject. In some cases, the biomarker comprises a B cell, a plasmablast a plasma cell, an autoantibody, or an immunoglobulin (Ig). In some cases, the biomarker comprises a B cell. In some cases, the biomarker comprises a plasmablast. In some cases, the biomarker comprises a plasma cell. In some cases, the biomarker comprises an autoantibody. In some cases, the biomarker comprises an immunoglobulin (Ig). In some cases, the biomarker comprises a B cell, a plasmablast, a plasma cell, an autoantibody, and an immunoglobulin (Ig). In some cases, the biomarker comprises a mature B cell, a memory B cell, or an activated B cell. In some cases, the biomarker comprises a mature B cell. In some cases, the biomarker comprises a memory B cell. In some cases, the biomarker comprises an activated B cell. In some cases, the biomarker comprises a mature B cell, a memory B cell, and an activated B cell. In some cases, the biomarker comprises a free kappa light chain or a free lambda light chain. In some cases, the biomarker comprises a free kappa light chain. In some cases, the biomarker comprises a free lambda light chain. In some cases, the biomarker comprises a free kappa light chain and a free lambda light chain. In some cases, the immunoglobulin comprises IgD, IgG, IgA, or IgM. In some cases, the immunoglobulin comprises IgD. In some cases, the immunoglobulin comprises IgG. In some cases, the immunoglobulin comprises IgA. In some cases, the immunoglobulin comprises IgM. In some cases, the therapeutically effective amount is calculated based on an amount of the biomarker. In some cases, the therapeutically effective amount is calculated based on an amount of the biomarker in tonsil, mucosal lamina propria (LP), blood, spleen, lymph node, or bone marrow, and optionally the lymph node is mesenteric lymiph node. In some cases, the therapeutically effective amount is calculated based on an amount of the biomarker in tonsil. In some cases, the therapeutically effective amount is calculated based on an amount of the biomarker in mucosal lamina propria (LP). In some cases, the therapeutically effective amount is calculated based on an amount of the biomarker in blood. In some cases, the therapeutically effective amount is calculated based on an amount of the biomarker in spleen. In some cases, the therapeutically effective amount is calculated based on an amount of the biomarker in lymph node. In some cases, the therapeutically effective amount is calculated based on an amount of the biomarker in mesenteric lymphWSGR Docket No. 69143-718.601node. In some cases, the therapeutically effective amount is calculated based on an amount of the biomarker in bone marrow. In some cases, tire therapeutically effective amount is calculated based on a reduction in the amount of the biomarker in the tonsil, mucosal lamina propria (LP), blood, spleen, lymph node or bone marrow after the administering, and optionally the lymph node is mesenteric lymph node. In some cases, the therapeutically effective amount is calculated based on a reduction in the amount of the biomarker in the tonsil after the administering. In some cases, the therapeutically effective amount is calculated based on a reduction in the amount of the biomarker in the mucosal LP after the administering. In some cases, the therapeutically effective amount is calculated based on a reduction in the amount of the biomarker in the blood after the administering. In some cases, the therapeutically effective amount is calculated based on a reduction in the amount of the biomarker in the spleen after the administering. In some cases, the therapeutically effective amount is calculated based on a reduction in tire amount of the biomarker in the lymph node after the administering. In some cases, the therapeutically effective amount is calculated based on a reduction in the amount of the biomarker in the mesenteric lymph node after the administering. In some cases, the therapeutically effective amount is calculated based on a reduction in the amount of the biomarker in the bone marrow after the administering. In some cases, the antibody or antigen-binding portion thereof is administered subcutaneously, intramuscularly or intravenously. In some cases, the antibody or antigen-binding portion thereof is administered subcutaneously. In some cases, the antibody or antigen-binding portion thereof is administered intramuscularly. In some cases, the antibody or antigen-binding portion thereof is administered intravenously. In some cases, the antibody or antigen-binding portion thereof is administered subcutaneously.

[0066] In some cases, the administering results in elimination or reduction of a B cell, a plasmablast, or a plasma cell. In some cases, the administering results in elimination or reduction of a B cell. In some cases, the administering results in elimination or reduction of a plasmablast. In some cases, the administering results in elimination or reduction of a plasma cell. In some cases, the administering results in elimination or reduction of a B cell, a plasmablast, and a plasma cell. In some cases, the administering results in elimination or reduction of a mature B cell, a memory B cell, or an activated B cell. In some cases, the administering results in elimination or reduction of a mature B cell. In some cases, the administering results in elimination or reduction of a memory B cell. In some cases, the administering results in el imination or reduction of an activated B cell. In some cases, the administering results in elimination or reduction of a mature B cell, a memory B cell, and an activated B cell. In some cases, the administering results in elimination or reduction of an autoantibody. In some cases, the administering results in elimination or reduction of the B cell, the plasmablast, or the plasma cell through antibody -dependent cellular cytotoxicity (ADCC), antibody-dependent cellular phagocytosis (ADCP), and / or complementdependent cytotoxicity (CDC). In some cases, the administering results in elimination or reduction of the B cell through antibody-dependent cellular cytotoxicity (ADCC). In some cases, the administering results in elimination or reduction of the plasmablast through antibody-dependent cellular cytotoxicity (ADCC). In some cases, the administering results in elimination or reduction of the plasma cell through antibodydependent cellular cytotoxicity (ADCC). In some cases, the administering results in elimination or reduction of the B cell, the plasmablast, and the plasma cell through antibody-dependent cellularWSGR Docket No. 69143-718.601cytotoxicity (ADCC). In some cases, the administering results in elimination or reduction of the B cell through antibody-dependent cellular phagocytosis (ADCP). In some cases, the administering results in elimination or reduction of the plasmablast through antibody -dependent cellular phagocytosis (ADCP). In some cases, the administering results in elimination or reduction of the plasma cell through antibody-dependent cellular phagocytosis (ADCP). In some cases, the administering results in elimination or reduction of the B cell, the plasmablast, and the plasma cell through antibody-dependent cellular phagocytosis (ADCP). In some cases, the administering results in elimination or reduction of the B cell through complement-dependent cytotoxicity (CDC). In some cases, the administering results in elimination or reduction of the plasmablast through complement-dependent cytotoxicity (CDC). In some cases, the administering results in elimination or reduction of the plasma cell through complementdependent cytotoxicity (CDC). In some cases, the administering results in elimination or reduction of the B cell, the plasmablast, and the plasma cell through complement-dependent cytotoxicity’ (CDC), In some cases, the administering results in elimination or reduction of the B cell, the plasmablast, or the plasma cell and the B cell, the plasmablast, or the plasma cell expresses CD 19. In some cases, the administering results in elimination or reduction of the B cell and tire B cell expresses CD 19. In some cases, the administering results in elimination or reduction of the plasmablast and the plasmablast expresses CD19. In some cases, the administering results in elimination or reduction of the plasma cell and the plasma cell expresses CD19. In some cases, the administering results in elimination or reduction of the B cell, the plasmablast, and the plasma cell and the B cell, the plasmablast, and the plasma cell each expresses CD 19. In some cases, the administering results in elimination or reduction of the B cell, the plasmablast, or the plasma cell and the B cell, the plasmablast, or the plasma cell expresses CD20. In some cases, the administering results in elimination or reduction of tire B cell and the B cell expresses CD20. In some cases, the administering results in elimination or reduction of the plasmablast and the plasmablast expresses CD20. In some cases, the administering results in elimination or reduction of the plasma cell and the plasma cell expresses CD20. In some cases, the administering results in elimination or reduction of the B cell, the plasmablast, and the plasma cell and the B cell, the plasmablast, and the plasma cell each expresses CD20. In some cases, the administering results in elimination or reduction of the B cell, the plasmablast, or the plasma cell and the B cell, the plasmablast, or the plasma cell expresses CD19 and CD20, or CD138. In some cases, the administering results in elimination or reduction of the B cell, the plasmablast, or tire plasma cell and the B cell, the plasmablast, or the plasma cell expresses CD 19 and CD20. In some cases, the administering results in elimination or reduction of the B cell, the plasmablast, or the plasma cell and the B cell, the plasmablast, or the plasma cell expresses CD 138. In some cases, tire administering results in elimination or reduction of the B cell and the B cell expresses CD 19 and CD20. In some cases, the administering results in elimination or reduction of the plasmablast and the plasmablast expresses CD19 and CD20. In some cases, the administering results in elimination or reduction of the plasma cell and the plasma cell expresses CD 19 and CD20. In some cases, the administering results in elimination or reduction of the B cell, the plasmablast, and the plasma cell and the B cell, the plasmablast, and the plasma cell each expresses CD 19 and CD20. In some cases, the administering results in elimination or reduction of the B cell and the B cell expresses CD 138. In some cases, the administeringWSGR Docket No. 69143-718.601results in elimination or reduction of the plasmablast and the plasmablast expresses CD138. In some cases, the administering results in elimination or reduction of the plasma cell and the plasma cell expresses CD 138. In some cases, the administering results in elimination or reduction of the B cell, the plasmablast, and the plasma cell and the B cell, the plasmablast, and the plasma cell each expresses CD 138. In some embodiments, the B cell, the plasmablast, or the plasma cell is in tonsil, mucosal lamina propria (LP), blood, spleen, lymph node, or bone marrow. In some embodiments, the B cell, the plasmablast, or the plasma cell is in blood. In some embodiments, the B cell, the plasmablast, or the plasma cell is in spleen. In some embodiments, the B cell, the plasmablast, or the plasma cell is in lymph node. In some embodiments, the B cell, the plasmablast, or the plasma cell is in bone marrow. In some embodiments, the B cell, the plasmablast, or the plasma cell is in blood, spleen, lymph node, or bone marrow. In some embodiments, the lymph node is mesenteric lymph node. In some embodiments, the administering results in an increase of a concentration of a cytokine and optionally the cytokine is in the serum. In some embodiments, the cytokine comprises interleukin 2 (IL-2), IL-6, interferon gamma (IFN-γ), tumor necrosis factor alpha (TNF-α), or any combination thereof. In some embodiments, the cytokine comprises interleukin 2 (IL-2), IL-6, interferon gamma (IFN-γ), and tumor necrosis factor alpha (TNF-α). In some embodiments, the increase of the concentration of the cytokine is transient or the concentration of the cytokine returns to a level similar to or same as a level before the administering after the increase. In some embodiments, the administering results in elimination or reduction of T cells. In some embodiments, the elimination or reduction of T cells is transient, or the number of T cells returns a level similar to, same as, or higher than, a level before the administering after the elimination or reduction. In some embodiments, the T cells are early activated T cells, late activated T cells, or proliferating T cells. In some embodiments, the T cells express CD69, CD25, Ki-67, or any combination thereof. In some embodiments, the administering results in an increase in the expression of CD25, CD69, or both, in T cells. In some embodiments, the T cells comprise CD4-positive T cells, CD8-positive T cells, or both. In some embodiments, the T cells are from tonsil, mucosal lamina propria (LP), blood, spleen, lymph node, or bone marrow, and optionally the lymph node is mesenteric lymph node. In some embodiments, the subject is a monkey. In some embodiments, the subject is a cynomolgus monkey. In some embodiments, the method further comprises administering a single dose or multiple doses of the antibody or antigenbinding fragment thereof. In some embodiments, the method further comprises administering the antibody or antigen-binding fragment thereof on a weekly basis. In some embodiments, the method further comprises administering a dose of about 0.5 mg / kg to 100 mg / kg of the antibody or antigen-binding fragment thereof and the dose is calculated based on tire weight of the subject, e.g., about 0.5 mg / kg, 1 mg / kg, 1.5 mg / kg, 2 mg / kg, 2.5 mg / kg, 3 mg / kg, 3.5 mg / kg, 4 mg / kg, 4.5 mg / kg, 5 mg / kg, 5.5 mg / kg, 6 mg / kg, 6.5 mg / kg, 7 mg / kg, 7.5 mg / kg, 8 mg / kg, 8.5 mg / kg, 9 mg / kg, 9.5 mg / kg, 10 mg / kg, 10.5 mg / kg, 11 mg / kg, 11.5 mg / kg, 12 mg / kg, 12.5 mg / kg, 13 mg / kg, 13.5 mg / kg, 14 mg / kg, 14.5 mg / kg, 15 mg / kg, 15.5 mg / kg, 16 mg / kg, 16.5 mg / kg, 17 mg / kg, 17.5 mg / kg, 18 mg / kg, 18.5 mg / kg, 19 mg / kg, 19.5 mg / kg, 20 mg / kg, 20.5 mg / kg, 21 mg / kg, 21.5 mg / kg, 22 mg / kg, 22.5 mg / kg, 23 mg / kg, 23.5 mg / kg, 24 mg / kg, 24.5 mg / kg, 25 mg / kg, 25.5 mg / kg, 26 mg / kg, 26.5 mg / kg, 27 mg / kg, 27.5 mg / kg, 28 mg / kg, 28.5 mg / kg, 29 mg / kg, 29.5 mg / kg, 30 mg / kg, 30.5 mg / kg, 31 mg / kg, 31.5 mg / kg, 32 mg / kg, 32.5 mg / kg, 33 mg / kg,WSGR Docket No. 69143-718.60133.5 mg / kg, 34 mg / kg, 34.5 mg / kg, 35 mg / kg, 35.5 mg / kg, 36 mg / kg, 36.5 mg / kg, 37 mg / kg, 37.5 mg / kg, 38 mg / kg, 38.5 mg / kg, 39 mg / kg, 39.5 mg / kg, 40 mg / kg, 40.5 mg / kg, 41 mg / kg, 41.5 mg / kg, 42 mg / kg, 42.5 mg / kg, 43 mg / kg, 43.5 mg / kg, 44 mg / kg, 44.5 mg / kg, 45 mg / kg, 45.5 mg / kg, 46 mg / kg, 46.5 mg / kg, 47 mg / kg, 47.5 mg / kg, 48 mg / kg, 48.5 mg / kg, 49 mg / kg, 49.5 mg / kg, 50 mg / kg, 50.5 mg / kg, 51 mg / kg, 51.5 mg / kg, 52 mg / kg, 52.5 mg / kg, 53 mg / kg, 53.5 mg / kg, 54 mg / kg, 54.5 mg / kg, 55 mg / kg, 55.5 mg / kg, 56 mg / kg, 56.5 mg / kg, 57 mg / kg, 57.5 mg / kg, 58 mg / kg, 58.5 mg / kg, 59 mg / kg, 59.5 mg / kg, 60 mg / kg, 60.5 mg / kg, 61 mg / kg, 61.5 mg / kg, 62 mg / kg, 62.5 mg / kg, 63 mg / kg, 63.5 mg / kg, 64 mg / kg, 64.5 mg / kg, 65 mg / kg, 65.5 mg / kg, 66 mg / kg, 66.5 mg / kg, 67 mg / kg, 67.5 mg / kg, 68 mg / kg, 68.5 mg / kg, 69 mg / kg, 69.5 mg / kg, 70 mg / kg, 70.5 mg / kg, 71 mg / kg, 71.5 mg / kg, 72 mg / kg, 72.5 mg / kg, 73 mg / kg, 73.5 mg / kg, 74 mg / kg, 74.5 mg / kg, 75 mg / kg, 75.5 mg / kg, 76 mg / kg, 76.5 mg / kg, 77 mg / kg, 77.5 mg / kg, 78 mg / kg, 78.5 mg / kg, 79 mg / kg, 79.5 mg / kg, 80 mg / kg, 80.5 mg / kg, 81 mg / kg, 81.5 mg / kg, 82 mg / kg, 82.5 mg / kg, 83 mg / kg, 83.5 mg / kg, 84 mg / kg, 84.5 mg / kg, 85 mg / kg, 85.5 mg / kg, 86 mg / kg, 86.5 mg / kg, 87 mg / kg, 87.5 mg / kg, 88 mg / kg, 88.5 mg / kg, 89 mg / kg, 89.5 mg / kg, 90 mg / kg, 90.5 mg / kg, 91 mg / kg, 91.5 mg / kg, 92 mg / kg, 92.5 mg / kg, 93 mg / kg, 93.5 mg / kg, 94 mg / kg, 94.5 mg / kg, 95 mg / kg, 95.5 mg / kg, 96 mg / kg, 96.5 mg / kg, 97 mg / kg, 97.5 mg / kg, 98 mg / kg, 98.5 mg / kg, 99 mg / kg, 99.5 mg / kg, or about 100 mg / kg, or any dose therebetween. In some embodiments, the method further comprises administering a single dose of 0.5 mg / kg, 1.5 mg / kg, 5 mg / kg, or 15 mg / kg of the antibody or antigen-binding fragment thereof on day 1 and the dose is calculated based on the weight of the subject. In some embodiments, the method further comprises administering a first dose and a second dose of the antibody or antigen-binding fragment thereof, wherein the first dose is administered on day 1 and the second dose is administered on day 8. In some embodiments, the first or second dose is about 0.5 mg / kg to 100 mg / kg of the antibody or antigen -binding fragment thereof and the dose is calculated based on the weight of the subject, e.g., about 0.5 mg / kg, 1 mg / kg, 1.5 mg / kg, 2 mg / kg, 2.5 mg / kg, 3 mg / kg, 3.5 mg / kg, 4 mg / kg, 4.5 mg / kg, 5 mg / kg, 5.5 mg / kg, 6 mg / kg, 6.5 mg / kg, 7 mg / kg, 7.5 mg / kg, 8 mg / kg, 8.5 mg / kg, 9 mg / kg, 9.5 mg / kg, 10 mg / kg, 10.5 mg / kg, 11 mg / kg, 11.5 mg / kg, 12 mg / kg, 12.5 mg / kg, 13 mg / kg, 13.5 mg / kg, 14 mg / kg, 14.5 mg / kg, 15 mg / kg, 15.5 mg / kg, 16 mg / kg, 16.5 mg / kg, 17 mg / kg, 17.5 mg / kg, 18 mg / kg, 18.5 mg / kg, 19 mg / kg, 19.5 mg / kg, 20 mg / kg, 20.5 mg / kg, 21 mg / kg, 21.5 mg / kg, 22 mg / kg, 22.5 mg / kg, 23 mg / kg, 23.5 mg / kg, 24 mg / kg, 24.5 mg / kg, 25 mg / kg, 25.5 mg / kg, 26 mg / kg, 26.5 mg / kg, 27 mg / kg, 27.5 mg / kg, 28 mg / kg, 28.5 mg / kg, 29 mg / kg, 29.5 mg / kg, 30 mg / kg, 30.5 mg / kg, 31 mg / kg, 31.5 mg / kg, 32 mg / kg, 32.5 mg / kg, 33 mg / kg, 33.5 mg / kg, 34 mg / kg, 34.5 mg / kg, 35 mg / kg, 35.5 mg / kg, 36 mg / kg, 36.5 mg / kg, 37 mg / kg, 37.5 mg / kg, 38 mg / kg, 38.5 mg / kg, 39 mg / kg, 39.5 mg / kg, 40 mg / kg, 40.5 mg / kg, 41 mg / kg, 41.5 mg / kg, 42 mg / kg, 42.5 mg / kg, 43 mg / kg, 43.5 mg / kg, 44 mg / kg, 44.5 mg / kg, 45 mg / kg, 45.5 mg / kg, 46 mg / kg, 46.5 mg / kg, 47 mg / kg, 47.5 mg / kg, 48 mg / kg, 48.5 mg / kg, 49 mg / kg, 49.5 mg / kg, 50 mg / kg, 50.5 mg / kg, 51 mg / kg, 51.5 mg / kg, 52 mg / kg, 52.5 mg / kg, 53 mg / kg, 53.5 mg / kg, 54 mg / kg, 54.5 mg / kg, 55 mg / kg, 55.5 mg / kg, 56 mg / kg, 56.5 mg / kg, 57 mg / kg, 57.5 mg / kg, 58 mg / kg, 58.5 mg / kg, 59 mg / kg, 59.5 mg / kg, 60 mg / kg, 60.5 mg / kg, 61 mg / kg, 61.5 mg / kg, 62 mg / kg, 62.5 mg / kg, 63 mg / kg, 63.5 mg / kg, 64 mg / kg, 64.5 mg / kg, 65 mg / kg, 65.5 mg / kg, 66 mg / kg, 66.5 mg / kg, 67 mg / kg, 67.5 mg / kg, 68 mg / kg, 68.5 mg / kg, 69 mg / kg, 69.5 mg / kg, 70 mg / kg, 70.5 mg / kg, 71 mg / kg, 71.5 mg / kg, 72 mg / kg, 72.5 mg / kg, 73 mg / kg, 73.5 mg / kg, 74 mg / kg, 74.5 mg / kg, 75 mg / kg, 75.5 mg / kg, 76 mg / kg, 76.5 mg / kg, 77 mg / kg, 77.5 mg / kg,WSGR Docket No. 69143-718.60178 mg / kg, 78.5 mg / kg, 79 mg / kg, 79.5 mg / kg, 80 mg / kg, 80.5 mg / kg, 81 mg / kg, 81.5 mg / kg, 82 mg / kg, 82.5 mg / kg, 83 mg / kg, 83.5 mg / kg, 84 mg / kg, 84.5 mg / kg, 85 mg / kg, 85.5 mg / kg, 86 mg / kg, 86.5 mg / kg, 87 mg / kg, 87.5 mg / kg, 88 mg / kg, 88.5 mg / kg, 89 mg / kg, 89.5 mg / kg, 90 mg / kg, 90.5 mg / kg, 91 mg / kg, 91.5 mg / kg, 92 mg / kg, 92.5 mg / kg, 93 mg / kg, 93.5 mg / kg, 94 mg / kg, 94.5 mg / kg, 95 mg / kg, 95.5 mg / kg, 96 mg / kg, 96.5 mg / kg, 97 mg / kg, 97.5 mg / kg, 98 mg / kg, 98.5 mg / kg, 99 mg / kg, 99.5 mg / kg, or about 100 mg / kg, or any dose therebetween. In some embodiments, the first dose and second dose are both 15 mg / kg and the dose is calculated based on the weight of the subject. In some embodiments, the first dose and second dose are 15 mg / kg and 100 mg / kg, respectively, and the dose is calculated based on the weight of the subject. In some embodiments, the administering results in a transient increase of IL-6 and INF-y levels in the serum within 8 hours after the administering on day 1. In some embodiments, the IL-6 and INF-y levels in the serum are similar to or the same as the levels before the administering within 24 to 48 hours after the administering on day 1. In some embodiments, the administering results in elimination or reduction of B cells in the blood within 4 hours or 24 hours after tire administering. In some embodiments, the administering results in elimination of B cells in the blood within 3 or 7 days after the administering. In some embodiments, the administering results in elimination of B cells in the blood that lasts at least until day 15 after the administering the second dose. In some embodiments, the administering results in elimination or reduction of T cells in the blood within 4 or 24 hours after the administering, wherein after the elimination or reduction, the number of T cells increases to a level that is higher than a level before the administering by day 8. In some embodiments, the administering results in an increase of T cells in the blood within 4 hours or 24 hours after the administering, wherein the T cells express CD69, CD25, Ki-67, or any combination thereof, wherein after the increase, the number of T cells is higher than the amount before the administering by day 8. In some embodiments, the number of T cells in the blood is the same as or higher than the number of T cells before the administering by day 15 after the administering the second dose. In some embodiments, the administering results in elimination or reduction of B cells in the bone marrow, spleen, or mesenteric lymph node and the percentage of elimination or reduction of B cells increases when the dose becomes higher. In some embodiments, the administering results in elimination or reduction of B cells in the bone marrow', spleen, and mesenteric lymph node and the percentage of elimination or reduction of B cells increases when the dose becomes higher. In some embodiments, the administering results in elimination of B cells in the bone marrow, spleen, and mesenteric lymph node at 5 mg / kg or higher doses. In some embodiments, the B cells express CD19, CD20, CD138, or any combination thereof. In some embodiments, the reduction of B cells is about 0-100%, e.g., about 1%, 2%, 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%, 30%, 31%, 32%, 33%, 34%, 35%, 36%, 37%, 38%, 39%, 40%, 41%, 42%, 43%, 44%. 45%, 46%, 47%. 48%, 49%, 50%, 51%, 52%, 53%, 54%, 55%. 56%, 57%, 58%, 59%, 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%, 95%, 96%, 97%, 98%, 99%, or about 100%, or any percentage therebetween.

[0067] In some cases, the method further comprises revaccinating the subject. In some cases, the method further comprises administering to the subject a pharmaceutical composition comprising the antibody orWSGR Docket No. 69143-718.601antigen-binding fragment thereof or the one or more polynucleotide encoding the antibody or antigen-binding portion thereof, and a pharmaceutically acceptable carrier or excipient. In some cases, the method further comprises administering to the subject a pharmaceutical composition comprising the antibody or antigen -binding fragment thereof and a pharmaceutically acceptable carrier or excipient. In some cases, the method further comprises administering to the subject a pharmaceutical composition comprising the one or more polynucleotide encoding the antibody or antigen-binding portion thereof, and a pharmaceutically acceptable carrier or excipient.

[0068] In some embodiments, (a) the CD 19 binding moiety comprises a heavy chain variable region (CD19VH) and a light chain variable region (CD19VL); (b) the CD3 binding moiety comprises a heavy chain variable region (CD3VH) and a light chain variable region (CD3VL); and (c) the CD20 binding moiety comprises a heavy chain variable region (CD20VH) and a light chain variable region (CD20VL). In some embodiments, the antibody or antigen-binding portion thereof further comprises a first binding arm and a second binding arm, wherein the first binding arm comprises the CD 19 binding moiety and the CD3 binding moiety and the second binding arm comprises the CD20 binding moiety.

[0069] In some embodiments, the CD19VH comprises an amino acid sequence with about 70% to about 100% sequence identity to SEQ ID NO: 19, e.g, about 70%, 71%, 72%, 73%, 74%, 75%, 76%, 77%, 78%, 79%, 80%, 81%, 82%. 83%, 84%, 85%. 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%. 94%, 95%, 96%, 97%, 98%, 99%, or about 100% sequence identity, or any percentage there between. In some embodiments, the CD19VL comprises an amino acid sequence with about 70% to about 100% sequence identity to SEQ ID NO: 20, e.g, about 70%, 71%, 72%, 73%, 74%, 75%, 76%, 77%, 78%, 79%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%. 96%, 97%, 98%.99%, or about 100% sequence identity, or any percentage there between. In some embodiments, the CD3VH comprises an amino acid sequence with about 70% to about 100% sequence identity to SEQ ID NO: 21, e.g., about 70%, 71%, 72%, 73%, 74%, 75%, 76%, 77%, 78%, 79%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%. 90%, 91%, 92%. 93%, 94%, 95%, 96%, 97%, 98%, 99%, or about 100% sequence identity, or any percentage there between. In some embodiments, the CD3VL comprises an amino acid sequence with about 70% to about 100% sequence identity to SEQ ID NO: 22, e.g., about 70%, 71%, 72%, 73%, 74%, 75%, 76%, 77%, 78%, 79%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or about 100% sequence identity, or any percentage there between. In some embodiments, the CD20VH comprises an amino acid sequence with about 70% to about 100% sequence identity to SEQ ID NO: 23, e.g., about 70%, 71%, 72%, 73%, 74%, 75%, 76%, 77%, 78%, 79%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or about 100% sequence identity, or any percentage there between. In some embodiments, the CD20VL comprises an amino acid sequence with about 70% to about 100% sequence identity to SEQ ID NO: 24, e.g, about 70%, 71%, 72%, 73%, 74%, 75%, 76%, 77%, 78%, 79%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or about 100% sequence identity, or any percentage there between. In some embodiments, (a) the CD19VH comprises an amino acid sequence with at least 70% sequence identity to SEQ ID NO: 19; (b) the CD19VL comprises an amino acid sequence with at least 70% sequence identityWSGR Docket No. 69143-718.601to SEQ ID NO: 20; (c) the CD3VH comprises an amino acid sequence with at least 70% sequence identity to SEQ ID NO: 21; (d) the CD3VL comprises an amino acid sequence with at least 70% sequence identity to SEQ ID NO: 22; (e) the CD20VH comprises an amino acid sequence with at least 70% sequence identity to SEQ ID NO: 23; or (f ) the CD20VL comprises an amino acid sequence with at least 70% sequence identity to SEQ ID NO: 24, In some embodiments, (a) the CD19VH comprises an amino acid sequence with at least 70% sequence identity to SEQ ID NO: 19; (b) the CD19VL comprises an amino acid sequence with at least 70% sequence identity to SEQ ID NO: 20; (c) the CD3VH comprises an amino acid sequence with at least 70% sequence identity to SEQ ID NO: 21; (d) the CD3VL comprises an amino acid sequence with at least 70% sequence identity to SEQ ID NO: 22; (e) the CD20VH comprises an amino acid sequence with at least 70% sequence identity to SEQ ID NO: 23; and (f ) the CD20VL comprises an amino acid sequence with at least 70% sequence identity to SEQ ID NO: 24. In some embodiments, (a) the CD19VH comprises an amino acid sequence with at least 75% sequence identity to SEQ ID NO: 19; (b) the CD19VL comprises an amino acid sequence with at least 75% sequence identity to SEQ ID NO: 20; (c) the CD3VH comprises an amino acid sequence with at least 75% sequence identity to SEQ ID NO: 21; (d) the CD3VL comprises an amino acid sequence with at least 75% sequence identity to SEQ ID NO: 22; (e) the CD20VH comprises an amino acid sequence with at least 75% sequence identity to SEQ ID NO: 23; or (f ) the CD20VL comprises an amino acid sequence with at least 75% sequence identity to SEQ ID NO: 24. In some embodiments, (a) the CD19VH comprises an amino acid sequence with at least 75% sequence identity to SEQ ID NO: 19; (b) the CD19VL comprises an amino acid sequence with at least 75% sequence identity to SEQ ID NO: 20; (c) the CD3VH comprises an amino acid sequence with at least 75% sequence identity to SEQ ID NO: 21; (d) the CD3VL comprises an amino acid sequence with at least 75% sequence identity to SEQ ID NO: 22; (e) the CD20VH comprises an amino acid sequence with at least 75% sequence identity to SEQ ID NO: 23; and (f ) the CD20VL comprises an amino acid sequence with at least 75% sequence identity to SEQ ID NO: 24. In some embodiments, (a) the CD19VH comprises an amino acid sequence with at least 80% sequence identity to SEQ ID NO: 19; (b) the CD19VL comprises an amino acid sequence with at least 80% sequence identity to SEQ ID NO: 20; (c) the CD3VH comprises an amino acid sequence with at least 80% sequence identity to SEQ ID NO: 21; (d) the CD3VL comprises an amino acid sequence with at least 80% sequence identity to SEQ ID NO: 22; (e) the CD20VH comprises an amino acid sequence with at least 80% sequence identity to SEQ ID NO: 23; or (f ) the CD20VL comprises an amino acid sequence with at least 80% sequence identity to SEQ ID NO: 24. In some embodiments, (a) the CD19VH comprises an amino acid sequence with at least 80% sequence identity to SEQ ID NO: 19; (b) the CD19VL comprises an amino acid sequence with at least 80% sequence identity to SEQ ID NO: 20; (c) the CD3VH comprises an amino acid sequence with at least 80% sequence identity to SEQ ID NO: 21; (d) the CD3VL comprises an amino acid sequence with at least 80% sequence identity to SEQ ID NO: 22; (e) the CD20VH comprises an amino acid sequence with at least 80% sequence identity to SEQ ID NO: 23; and (f ) the CD20VL comprises an amino acid sequence with at least 80% sequence identity to SEQ ID NO: 24. In some embodiments, (a) the CD19VH comprises an amino acid sequence with at least 85% sequence identity to SEQ ID NO: 19; (b) the CD19VL comprises an amino acid sequence with at least 85% sequence identityWSGR Docket No. 69143-718.601to SEQ ID NO: 20; (c) the CD3VH comprises an amino acid sequence with at least 85% sequence identity to SEQ ID NO: 21; (d) the CD3VL comprises an amino acid sequence with at least 85% sequence identity to SEQ ID NO: 22; (e) the CD20VH comprises an amino acid sequence with at least 85% sequence identity to SEQ ID NO: 23; or (f ) the CD20VL comprises an amino acid sequence with at least 85% sequence identity to SEQ ID NO: 24, In some embodiments, (a) the CD19VH comprises an amino acid sequence with at least 85% sequence identity to SEQ ID NO: 19; (b) the CD19VL comprises an amino acid sequence with at least 85% sequence identity to SEQ ID NO: 20; (c) the CD3 VH comprises an amino acid sequence with at least 85% sequence identity to SEQ ID NO: 21; (d) the CD3VL comprises an amino acid sequence with at least 85% sequence identity to SEQ ID NO: 22; (e) the CD20VH comprises an amino acid sequence with at least 85% sequence identity to SEQ ID NO: 23; and (f ) the CD20VL comprises an amino acid sequence with at least 85% sequence identity to SEQ ID NO: 24. In some embodiments, (a) the CD19VH comprises an amino acid sequence with at least 86% sequence identity to SEQ ID NO: 19; (b) the CD19VL comprises an amino acid sequence with at least 86% sequence identity to SEQ ID NO: 20; (c) the CD3VH comprises an amino acid sequence with at least 86% sequence identity to SEQ ID NO: 21; (d) the CD3VL comprises an amino acid sequence with at least 86% sequence identity to SEQ ID NO: 22; (e) the CD20VH comprises an amino acid sequence with at least 86% sequence identity to SEQ ID NO: 23; or (f ) the CD20VL comprises an amino acid sequence with at least 86% sequence identity to SEQ ID NO: 24. In some embodiments, (a) the CD19VH comprises an amino acid sequence with at least 86% sequence identity to SEQ ID NO: 19; (b) the CD19VL comprises an amino acid sequence with at least 86% sequence identity to SEQ ID NO: 20; (c) the CD3VH comprises an amino acid sequence with at least 86% sequence identity to SEQ ID NO: 21; (d) the CD3VL comprises an amino acid sequence with at least 86% sequence identity to SEQ ID NO: 22; (e) the CD20VH comprises an amino acid sequence with at least 86% sequence identity to SEQ ID NO: 23; and (f ) the CD20VL comprises an amino acid sequence with at least 86% sequence identity to SEQ ID NO: 24. In some embodiments, (a) the CD19VH comprises an amino acid sequence with at least 87% sequence identity to SEQ ID NO: 19; (b) the CD19VL comprises an amino acid sequence with at least 87% sequence identity to SEQ ID NO: 20; (c) the CD3VH comprises an amino acid sequence with at least 87% sequence identity to SEQ ID NO: 21; (d) the CD3VL comprises an amino acid sequence with at least 87% sequence identity to SEQ ID NO: 22; (e) the CD20VH comprises an amino acid sequence with at least 87% sequence identity to SEQ ID NO: 23; or (f ) the CD20VL comprises an amino acid sequence with at least 87% sequence identity to SEQ ID NO: 24. In some embodiments, (a) the CD19VH comprises an amino acid sequence with at least 87% sequence identity to SEQ ID NO: 19; (b) the CD19VL comprises an amino acid sequence with at least 87% sequence identity to SEQ ID NO: 20; (c) the CD3VH comprises an amino acid sequence with at least 87% sequence identity to SEQ ID NO: 21; (d) the CD3VL comprises an amino acid sequence with at least 87% sequence identity to SEQ ID NO: 22; (e) the CD20VH comprises an amino acid sequence with at least 87% sequence identity to SEQ ID NO: 23; and (f ) the CD20VL comprises an amino acid sequence with at least 87% sequence identity to SEQ ID NO: 24. In some embodiments, (a) the CD19VH comprises an amino acid sequence with at least 88% sequence identity to SEQ ID NO: 19; (b) the CD19VL comprises an amino acid sequence with at least 88% sequence identityWSGR Docket No. 69143-718.601to SEQ ID NO: 20; (c) the CD3VH comprises an amino acid sequence with at least 88% sequence identity to SEQ ID NO: 21; (d) the CD3VL comprises an amino acid sequence with at least v% sequence identity to SEQ ID NO: 22; (e) the CD20VH comprises an amino acid sequence with at least 88% sequence identity to SEQ ID NO: 23; or (f ) the CD20VL comprises an amino acid sequence with at least 88% sequence identity to SEQ ID NO: 24, In some embodiments, (a) the CD19VH comprises an amino acid sequence with at least 88% sequence identity to SEQ ID NO: 19; (b) the CD19VL comprises an amino acid sequence with at least 88% sequence identity to SEQ ID NO: 20; (c) the CD3VH comprises an amino acid sequence with at least 88% sequence identity to SEQ ID NO: 21; (d) the CD3VL comprises an amino acid sequence with at least 88% sequence identity to SEQ ID NO: 22; (e ) the CD20VH comprises an amino acid sequence with at least 88% sequence identity to SEQ ID NO: 23; and (f) the CD20VL comprises an amino acid sequence with at least 88% sequence identity to SEQ ID NO: 24. In some embodiments, (a) the CD19VH comprises an amino acid sequence with at least 89% sequence identity to SEQ ID NO: 19; (b) the CD19VL comprises an amino acid sequence with at least 89% sequence identity to SEQ ID NO: 20; (c) the CD3VH comprises an amino acid sequence with at least 89% sequence identity to SEQ ID NO: 21; (d) the CD3VL comprises an amino acid sequence with at least 89% sequence identity to SEQ ID NO: 22; (e) the CD20VH comprises an amino acid sequence with at least 89% sequence identity to SEQ ID NO: 23; or (f ) the CD20VL comprises an amino acid sequence with at least 89% sequence identity to SEQ ID NO: 24. In some embodiments, (a) the CD19VH comprises an amino acid sequence with at least 89% sequence identity to SEQ ID NO: 19; (b) the CD19VL comprises an amino acid sequence with at least 89% sequence identity to SEQ ID NO: 20; (c) the CD3VH comprises an amino acid sequence with at least 89% sequence identity to SEQ ID NO: 21; (d) the CD3VL comprises an amino acid sequence with at least 89% sequence identity to SEQ ID NO: 22; (e ) the CD20VH comprises an amino acid sequence with at least 89% sequence identity to SEQ ID NO: 23; and (f) the CD20VL comprises an amino acid sequence with at least 89% sequence identity to SEQ ID NO: 24. In some embodiments, (a) the CD19VH comprises an amino acid sequence with at least 90% sequence identity to SEQ ID NO: 19; (b) the CD19VL comprises an amino acid sequence with at least 90% sequence identity to SEQ ID NO: 20; (c) the CD3VH comprises an amino acid sequence with at least 90% sequence identity to SEQ ID NO: 21; (d) the CD3VL comprises an amino acid sequence with at least 90% sequence identity to SEQ ID NO: 22; (e) the CD20VH comprises an amino acid sequence with at least 90% sequence identity to SEQ ID NO: 23; or (f) the CD20VL comprises an amino acid sequence with at least 90% sequence identity to SEQ ID NO: 24. In some embodiments, (a) the CD19VH comprises an amino acid sequence with at least 90% sequence identity to SEQ ID NO: 19; (b) the CD19VL comprises an amino acid sequence with at least 90% sequence identity to SEQ ID NO: 20; (c) the CD3VH comprises an amino acid sequence with at least 90% sequence identity to SEQ ID NO: 21; (d) the CD3VL comprises an amino acid sequence with at least 90% sequence identity to SEQ ID NO: 22; (e ) the CD20VH comprises an amino acid sequence with at least 90% sequence identity to SEQ ID NO: 23; and (f) the CD20VL comprises an amino acid sequence with at least 90% sequence identity to SEQ ID NO: 24. In some embodiments, (a) the CD19VH comprises an amino acid sequence with at least 91% sequence identity to SEQ ID NO: 19; (b) the CD19VL comprises an amino acid sequence with at least 91% sequence identityWSGR Docket No. 69143-718.601to SEQ ID NO: 20; (c) the CD3VH comprises an amino acid sequence with at least 91% sequence identity to SEQ ID NO: 21; (d) the CD3VL comprises an amino acid sequence with at least 91% sequence identity to SEQ ID NO: 22; (e) the CD20VH comprises an amino acid sequence with at least 91% sequence identity to SEQ ID NO: 23; or (f) the CD20VL comprises an amino acid sequence with at least 91 % sequence identity to SEQ ID NO: 24, In some embodiments, (a) the CD19VH comprises an amino acid sequence with at least 91% sequence identity to SEQ ID NO: 19; (b) the CD19VL comprises an amino acid sequence with at least 91% sequence identity to SEQ ID NO: 20; (c) the CD3VH comprises an amino acid sequence with at least 91% sequence identity to SEQ ID NO: 21; (d) the CD3VL comprises an amino acid sequence with at least 91 % sequence identity to SEQ ID NO: 22; (e )the CD20VH comprises an amino acid sequence with at least 91% sequence identity to SEQ ID NO: 23; and (f) the CD20VL comprises an amino acid sequence with at least 91% sequence identity to SEQ ID NO: 24. In some embodiments, (a) the CD19VH comprises an amino acid sequence with at least 92% sequence identity to SEQ ID NO: 19; (b) the CD19VL comprises an amino acid sequence with at least 92% sequence identity to SEQ ID NO: 20; (c) the CD3VH comprises an amino acid sequence with at least 92% sequence identity to SEQ ID NO: 21; (d) the CD3VL comprises an amino acid sequence with at least 92% sequence identity to SEQ ID NO: 22; (e) the CD20VH comprises an amino acid sequence with at least 92% sequence identity to SEQ ID NO: 23; or (f) the CD20VL comprises an amino acid sequence with at least 92% sequence identity to SEQ ID NO: 24. In some embodiments, (a) the CD19VH comprises an amino acid sequence with at least 92% sequence identity to SEQ ID NO: 19; (b) the CD19VL comprises an amino acid sequence with at least 92% sequence identity to SEQ ID NO: 20; (c) the CD3VH comprises an amino acid sequence with at least 92% sequence identity to SEQ ID NO: 21; (d) the CD3VL comprises an amino acid sequence with at least 92% sequence identity to SEQ ID NO: 22; (e) the CD20VH comprises an amino acid sequence with at least 92% sequence identity to SEQ ID NO: 23; and (1) the CD20VL comprises an amino acid sequence with at least 92% sequence identity to SEQ ID NO: 24. In some embodiments, (a) the CD19VH comprises an amino acid sequence with at least 93% sequence identity to SEQ ID NO: 19; (b) the CD19VL comprises an amino acid sequence with at least 93% sequence identity to SEQ ID NO: 20; (c) the CD3VH comprises an amino acid sequence with at least 93% sequence identity to SEQ ID NO: 21; (d) the CD3VL comprises an amino acid sequence with at least 93% sequence identity to SEQ ID NO: 22; (e) the CD20VH comprises an amino acid sequence with at least 93% sequence identity to SEQ ID NO: 23; or (f) the CD20VL comprises an amino acid sequence with at least 93% sequence identity to SEQ ID NO: 24. In some embodiments, (a) the CD19VH comprises an amino acid sequence with at least 93% sequence identity to SEQ ID NO: 19; (b) the CD19VL comprises an amino acid sequence with at least 93% sequence identity to SEQ ID NO: 20; (c) the CD3VH comprises an amino acid sequence with at least 93% sequence identity to SEQ ID NO: 21; (d) the CD3VL comprises an amino acid sequence with at least 93% sequence identity to SEQ ID NO: 22; (e) the CD20VH comprises an amino acid sequence with at least 93% sequence identity to SEQ ID NO: 23; and (f) the CD20VL comprises an amino acid sequence with at least 93% sequence identity' to SEQ ID NO: 24. In some embodiments, (a) the CD19VH comprises an amino acid sequence with at least 94% sequence identity to SEQ ID NO: 19; (b) the CD19VL comprises an amino acid sequence with at least 94% sequence identityWSGR Docket No. 69143-718.601to SEQ ID NO: 20; (c) the CD3VH comprises an amino acid sequence with at least 94% sequence identity to SEQ ID NO: 21; (d) the CD3VL comprises an amino acid sequence with at least 94% sequence identity to SEQ ID NO: 22; (e) the CD20VH comprises an amino acid sequence with at least 94% sequence identity to SEQ ID NO: 23; or (f) the CD20VL comprises an amino acid sequence with at least 94% sequence identity to SEQ ID NO: 24, In some embodiments, (a) the CD19VH comprises an amino acid sequence with at least 94% sequence identity to SEQ ID NO: 19; (b) the CD19VL comprises an amino acid sequence with at least 94% sequence identity to SEQ ID NO: 20; (c) the CD3VH comprises an amino acid sequence with at least 94% sequence identity to SEQ ID NO: 21; (d) the CD3VL comprises an amino acid sequence with at least 94% sequence identity to SEQ ID NO: 22; (e) the CD20VH comprises an amino acid sequence with at least 94% sequence identity to SEQ ID NO: 23; and (f) the CD20VL comprises an amino acid sequence with at least 94% sequence identity to SEQ ID NO: 24. In some embodiments, (a) the CD19VH comprises an amino acid sequence with at least 95% sequence identity to SEQ ID NO: 19; (b) the CD19VL comprises an amino acid sequence with at least 95% sequence identity to SEQ ID NO: 20; (c) the CD3VH comprises an amino acid sequence with at least 95% sequence identity to SEQ ID NO: 21; (d) the CD3VL comprises an amino acid sequence with at least 95% sequence identity to SEQ ID NO: 22; (e) the CD20VH comprises an amino acid sequence with at least 95% sequence identity to SEQ ID NO: 23; or (f) the CD20VL comprises an amino acid sequence with at least 95% sequence identity to SEQ ID NO: 24. In some embodiments, (a) the CD19VH comprises an amino acid sequence with at least 95% sequence identity to SEQ ID NO: 19; (b) the CD19 VL comprises an amino acid sequence with at least 95% sequence identity to SEQ ID NO: 20; (c) the CD3VH comprises an amino acid sequence with at least 95% sequence identity to SEQ ID NO: 21; (d) the CD3VL comprises an amino acid sequence with at least 95% sequence identity to SEQ ID NO: 22; (e) the CD20VH comprises an amino acid sequence with at least 95% sequence identity to SEQ ID NO: 23; and (f) the CD20VL comprises an amino acid sequence with at least 95% sequence identity to SEQ ID NO: 24. In some embodiments, (a) the CD19VH comprises an amino acid sequence with at least 96% sequence identity to SEQ ID NO: 19; (b) the CD19VL comprises an amino acid sequence with at least 96% sequence identity to SEQ ID NO: 20; (c) the CD3VH comprises an amino acid sequence with at least 96% sequence identity to SEQ ID NO: 21; (d) the CD3VL comprises an amino acid sequence with at least 96% sequence identity to SEQ ID NO: 22; (e) the CD20VH comprises an amino acid sequence with at least 96% sequence identity to SEQ ID NO: 23; or (f) the CD20VL comprises an amino acid sequence with at least 96% sequence identity to SEQ ID NO: 24. In some embodiments, (a) the CD19VH comprises an amino acid sequence with at least 96% sequence identity to SEQ ID NO: 19; (b) the CD19VL comprises an amino acid sequence with at least 96% sequence identity to SEQ ID NO: 20; (c) the CD3VH comprises an amino acid sequence with at least 96% sequence identity to SEQ ID NO: 21; (d) the CD3VL comprises an amino acid sequence with at least 96% sequence identity to SEQ ID NO: 22; (e) the CD20VH comprises an amino acid sequence with at least 96% sequence identity to SEQ ID NO: 23; and (f) the CD20VL comprises an amino acid sequence with at least 96% sequence identity' to SEQ ID NO: 24. In some embodiments, (a) the CD19VH comprises an amino acid sequence with at least 97% sequence identity to SEQ ID NO: 19; (b) the CD19VL comprises an amino acid sequence with at least 97% sequence identityWSGR Docket No. 69143-718.601to SEQ ID NO: 20; (c) the CD3VH comprises an amino acid sequence with at least 97% sequence identity to SEQ ID NO: 21; (d) the CD3VL comprises an amino acid sequence with at least 97% sequence identity to SEQ ID NO: 22; (e) the CD20VH comprises an amino acid sequence with at least 97% sequence identity to SEQ ID NO: 23; or (f) the CD20VL comprises an amino acid sequence with at least 97% sequence identity to SEQ ID NO: 24, In some embodiments, (a) the CD19VH comprises an amino acid sequence with at least 97% sequence identity to SEQ ID NO: 19; (b) the CD19VL comprises an amino acid sequence with at least 97% sequence identity to SEQ ID NO: 20; (c) the CD3VH comprises an amino acid sequence with at least 97% sequence identity to SEQ ID NO: 21; (d) the CD3VL comprises an amino acid sequence with at least 97% sequence identity to SEQ ID NO: 22; (e) the CD20VH comprises an amino acid sequence with at least 97% sequence identity to SEQ ID NO: 23; and (f) the CD20VL comprises an amino acid sequence with at least 97% sequence identity to SEQ ID NO: 24. In some embodiments, (a) the CD19VH comprises an amino acid sequence with at least 98% sequence identity to SEQ ID NO: 19; (b) the CD19VL comprises an amino acid sequence with at least 98% sequence identity to SEQ ID NO: 20; (c) the CD3VH comprises an amino acid sequence with at least 98% sequence identity to SEQ ID NO: 21; (d) the CD3VL comprises an amino acid sequence with at least 98% sequence identity to SEQ ID NO: 22; (e) the CD20VH comprises an amino acid sequence with at least 98% sequence identity to SEQ ID NO: 23; or (f) the CD20VL comprises an amino acid sequence with at least 98% sequence identity to SEQ ID NO: 24. In some embodiments, (a) the CD19VH comprises an amino acid sequence with at least 98% sequence identity to SEQ ID NO: 19; (b) the CD19VL comprises an amino acid sequence with at least 98% sequence identity to SEQ ID NO: 20; (c) the CD3VH comprises an amino acid sequence with at least 98% sequence identity to SEQ ID NO: 21; (d) the CD3VL comprises an amino acid sequence with at least 98% sequence identity to SEQ ID NO: 22; (e) the CD20VH comprises an amino acid sequence with at least 98% sequence identity to SEQ ID NO: 23; and (f) the CD20VL comprises an amino acid sequence with at least 98% sequence identity to SEQ ID NO: 24. In some embodiments, (a) the CD19VH comprises an amino acid sequence with at least 99% sequence identity to SEQ ID NO: 19; (b) the CD19VL comprises an amino acid sequence with at least 99% sequence identity to SEQ ID NO: 20; (c) the CD3VH comprises an amino acid sequence with at least 99% sequence identity to SEQ ID NO: 21; (d) the CD3VL comprises an amino acid sequence with at least 99% sequence identity to SEQ ID NO: 22; (e) the CD20VH comprises an amino acid sequence with at least 99% sequence identity to SEQ ID NO: 23; or (f) the CD20VL comprises an amino acid sequence with at least 99% sequence identity to SEQ ID NO: 24. In some embodiments, (a) the CD19VH comprises an amino acid sequence with at least 99% sequence identity to SEQ ID NO: 19; (b) the CD19VL comprises an amino acid sequence with at least 99% sequence identity to SEQ ID NO: 20; (c) the CD3VH comprises an amino acid sequence with at least 99% sequence identity to SEQ ID NO: 21; (d) the CD3VL comprises an amino acid sequence with at least 99% sequence identity to SEQ ID NO: 22; (e) the CD20VH comprises an amino acid sequence with at least 99% sequence identity to SEQ ID NO: 23; and (f) the CD20VL comprises an amino acid sequence with at least 99% sequence identity to SEQ ID NO: 24.

[0070] In some embodiments, (a) the CD19VH comprises the amino acid sequence of SEQ ID NO: 19; (b) the CD19VL comprises the amino acid sequence of SEQ ID NO: 20; (c) the CD3VH comprises theWSGR Docket No. 69143-718.601amino acid sequence of SEQ ID NO: 21; (d) the CD3VL comprises the amino acid sequence of SEQ ID NO: 22; (e) the CD20VH comprises the amino acid sequence of SEQ ID NO: 23; or (f) the CD20VL comprises the amino acid sequence of SEQ ID NO: 24. In some embodiments, (a) the CD19VH comprises the amino acid sequence of SEQ ID NO: 19; (b) the CD19VL comprises the amino acid sequence of SEQ ID NO: 20; (c) the CD3VII comprises the amino acid sequence of SEQ ID NO: 21; (d) the CD3VL comprises the amino acid sequence of SEQ ID NO: 22; (e) the CD20VH comprises the amino acid sequence of SEQ ID NO: 23; and (f) tire CD20VL comprises the amino acid sequence of SEQ ID NO: 24.

[0071] In some embodiments, (a) the CD19VH is operably linked to a first heavy chain constant domain (Cm); (b) the CD19VL is operably linked to a first light chain constant domain (C1L); (c) the CD3VH is operably linked to a second heavy chain constant domain (C2H); (d) the CD3 VL is operably linked to a second light chain constant domain (C2L); (e) the CD20VH is operably linked to a third heavy chain constant domain (C3H); or (f) the CD20VL is operably linked to a third light chain constant domain (C3L). In some embodiments, (a) the CD19VH is operably linked to a first heavy chain constant domain (Cm); (b) the CD19VL is operably linked to a first light chain constant domain (C1L); (c) the CD3VH is operably linked to a second heavy chain constant domain (C2H); (d) the CD3VL is operably linked to a second light chain constant domain (C2L); (e) the CD20VH is operably linked to a third heavy chain constant domain (C3H); and (f) the CD20VL is operably linked to a third light chain constant domain (C3L). In some embodiments, (a) the C1H and C1L comprise a T cell receptor (TCR) α chain constant domain (Cα) and a TCR β chain constant domain (Cβ), respectively; (b) the C1H and C1L comprise Cβ and Cα, respectively; or (c) the C1H and C1L comprise an antibody heavy chain constant region CH1 domain and an antibody light chain constant region CL domain, respectively. In some embodiments, the C1H and the C1L comprise Cα and Cβ, respectively. In some embodiments, the C1H and the C1L comprise Cβ and Cα, respectively. In some embodiments, the C1H and the C1L comprise CH1 domain and CL domain, respectively. In some embodiments, (a) the C2H and the C2L comprise Cα and Cβ, respectively; (b) the C2H and the C2L comprise Cβ and Cα, respectively; or (c) the C2H and the C2L comprise CH1 domain and CL domain, respectively. In some embodiments, the C2H and the C2L comprise Cα and Cβ, respectively. In some embodiments, the C2H and the C2L comprise Cβ and Cα, respectively. In some embodiments, the C2H and the C2L comprise CH1 domain and CL domain, respectively. In some embodiments, (a) the C3H and the C3L comprise Cα and Cβ, respectively; (b) the C3H and the C3L comprise Cβ and Cα, respectively; or (c) the C3H and the C3L comprise CH1 domain and CL domain, respectively. In some embodiments, the C3H and the C3L comprise Cα and Cβ, respectively. In some embodiments, the C3H and the C3L comprise Cβ and Cα, respectively. In some embodiments, the C3H and the C3L comprise CH1 domain and CL domain, respectively. In some embodiments, (a) the C1H and the C1L comprise Cβ and Cα, respectively; (b) the C2H and the C2L comprise Cβ and Cα, respectively; or (c) the C3H and the C3L comprise CH1 domain and CL domain, respectively. In some embodiments, (a) the C1H and the C1L comprise Cβ and Cα, respectively; (b) the C2H and the C2L comprise Cβ and Cα, respectively and (c) the C3H and the C3L comprise CH1 domain and CL domain, respectively. In some embodiments, (a) the C1H and the C1L comprise Cα and Cβ, respectively; (b) the C2H and the C2L comprise Cα and Cβ, respectively; or (c) the C3H and the C3L comprise CH1 domain and CL domain, respectively. In some embodiments, (a) the C1H and the C1L comprise Cα and Cβ, respectively; (b)WSGR Docket No. 69143-718.601the C2H and the C2L comprise Cα and Cβ, respectively; and (c) the C3H and the C3L comprise CH1 domain and CL domain, respectively.

[0072] In some embodiments, Cacomprises an amino acid sequence with about 70% to about 100% sequence identity to SEQ ID NO: 31, e.g., about 70%, 71%, 72%, 73%, 74%, 75%, 76%, 77%, 78%, 79%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%. 95%, 96%, 97%.98%, 99%, or about 100% sequence identity, or any percentage there between. In some embodiments, Cp comprises an amino acid sequence with about 70% to about 100% sequence identity to SEQ ID NO: 30, e.g., about 70%, 71%, 72%, 73%, 74%, 75%, 76%, 77%, 78%, 79%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or about 100% sequence identity, or any percentage there between. In some embodiments, CHI domain comprises an amino acid sequence with about 70% to about 100% sequence identity to SEQ ID NO: 36, e.g., about 70%, 71%, 72%, 73%, 74%, 75%, 76%, 77%, 78%, 79%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or about 100% sequence identity, or any percentage there between, in some embodiments, CL domain comprises an amino acid sequence with about 70% to about 100% sequence identity to SEQ ID NO: 37, e.g., about 70%, 71%, 72%, 73%, 74%, 75%, 76%, 77%, 78%, 79%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or about 100% sequence identity, or any percentage there between. In some embodiments, (a) Cacomprises an amino acid sequence with at least 70% sequence identity to SEQ ID NO: 31; (b) Cβ comprises an amino acid sequence with at least 70% sequence identity to SEQ ID NO: 30; (c) CHI domain comprises an amino acid sequence w ith at least 70% sequence identity to SEQ ID NO: 36; or (d) CL domain comprises an amino acid sequence with at least 70% sequence identity to SEQ ID NO: 37. In some embodiments, (a) Cacomprises an amino acid sequence with at least 75% sequence identity to SEQ ID NO: 31; (b) Cp comprises an amino acid sequence with at least 75% sequence identity to SEQ ID NO: 30; (c) CHI domain comprises an amino acid sequence with at least 75% sequence identity’ to SEQ ID NO: 36; or (d) CL domain comprises an amino acid sequence with at least 75% sequence identity to SEQ ID NO: 37. In some embodiments, (a) Cα comprises an amino acid sequence with at least 80% sequence identity to SEQ ID NO: 31; (b) Cp comprises an amino acid sequence with at least 80% sequence identity to SEQ ID NO: 30; (c) CHI domain comprises an amino acid sequence with at least 80% sequence identity to SEQ ID NO: 36; or (d) CL domain comprises an amino acid sequence with at 80% sequence identity to SEQ ID NO: 37. In some embodiments, (a) Cacomprises an amino acid sequence with at least 80% sequence identity to SEQ ID NO: 31; (b) Cp comprises an amino acid sequence with at least 80% sequence identity to SEQ ID NO: 30; (c) CHI domain comprises an amino acid sequence with at least 80% sequence identity to SEQ ID NO: 36; and (d) CL domain comprises an amino acid sequence with at 80% sequence identity to SEQ ID NO: 37. In some embodiments, (a) Cacomprises an amino acid sequence with at least 85% sequence identity to SEQ ID NO: 31; (b) Cp comprises an amino acid sequence with at least 85% sequence identity to SEQ ID NO: 30; (c) CHI domain comprises an amino acid sequence with at least 85% sequence identity to SEQ ID NO: 36; or (d) CL domain comprises an amino acid sequence with at least 85% sequence identity to SEQ ID NO: 37. In some embodiments, (a) Cacomprises an amino acid sequence with at least 85% sequenceWSGR Docket No. 69143-718.601identity to SEQ ID NO: 31; (b) Cp comprises an amino acid sequence with at least 85% sequence identity to SEQ ID NO: 30; (c) CHI domain comprises an amino acid sequence with at least 85% sequence identity to SEQ ID NO: 36; and (d) CL domain comprises an amino acid sequence with at least 85% sequence identity to SEQ ID NO: 37. In some embodiments, (a) Cacomprises an amino acid sequence with at least 86% sequence identity to SEQ ID NO: 31; (b) Cp comprises an amino acid sequence with at least 86% sequence identity to SEQ ID NO: 30; (c) CHI domain comprises an amino acid sequence with at least 86% sequence identity to SEQ ID NO: 36; or (d) CL domain comprises an amino acid sequence with at least 86% sequence identity to SEQ ID NO: 37. In some embodiments, (a) Cacomprises an amino acid sequence with at least 87% sequence identity to SEQ ID NO: 31; (b) Cp comprises an amino acid sequence with at least 87% sequence identity to SEQ ID NO: 30; (c) CHI domain comprises an amino acid sequence with at least 87% sequence identity to SEQ ID NO: 36; or (d) CL domain comprises an amino acid sequence with at least 87% sequence identity to SEQ ID NO: 37. In some embodiments, (a) Cacomprises an amino acid sequence with at least 88% sequence identity to SEQ ID NO: 31; (b) Cp comprises an amino acid sequence with at least 88% sequence identity to SEQ ID NO: 30; (c) CHI domain comprises an amino acid sequence with at least 88% sequence identity to SEQ ID NO: 36; or (d) CL domain comprises an amino acid sequence with at least 88% sequence identity to SEQ ID NO: 37. In some embodiments, (a) Cacomprises an amino acid sequence with at least 89% sequence identity to SEQ ID NO: 31; (b) Cp comprises an amino acid sequence with at least 89% sequence identity to SEQ ID NO: 30; (c) CHI domain comprises an amino acid sequence with at least 89% sequence identity to SEQ ID NO: 36; or (d) CL domain comprises an amino acid sequence with at least 89% sequence identity to SEQ ID NO: 37. In some embodiments, (a) Cacomprises an amino acid sequence with at least 90% sequence identity to SEQ ID NO: 31; (b) Cp comprises an amino acid sequence with at least 90% sequence identity to SEQ ID NO: 30; (c) CHI domain comprises an amino acid sequence with at least 90% sequence identity to SEQ ID NO: 36; or (d) CL domain comprises an amino acid sequence with at least 90% sequence identity to SEQ ID NO: 37. In some embodiments, (a) Cacomprises an amino acid sequence with at least 90% sequence identity to SEQ ID NO: 31; (b) Cp comprises an amino acid sequence with at least 90% sequence identity to SEQ ID NO: 30; (c) CH1 domain comprises an amino acid sequence with at least 90% sequence identity to SEQ ID NO: 36; and (d) CL domain comprises an amino acid sequence with at least 90% sequence identity to SEQ ID NO: 37, In some embodiments, (a) Cacomprises an amino acid sequence with at least 91% sequence identity to SEQ ID NO: 31; (b) Cp comprises an amino acid sequence with at least 91% sequence identity to SEQ ID NO: 30; (c) CHI domain comprises an amino acid sequence with at least 91% sequence identity to SEQ ID NO: 36; or (d) CL domain comprises an amino acid sequence with at least 91 % sequence identity to SEQ ID NO: 37, In some embodiments, (a) Cacomprises an amino acid sequence with at least 91% sequence identity to SEQ ID NO: 31; (b) Cp comprises an amino acid sequence with at least 91% sequence identity to SEQ ID NO: 30; (c) CHI domain comprises an amino acid sequence with at least 91% sequence identity to SEQ ID NO: 36; and (d) CL domain comprises an amino acid sequence with at least 91% sequence identity’ to SEQ ID NO: 37. In some embodiments, (a) Cacomprises an amino acid sequence with at least 92% sequence identity to SEQ ID NO: 31; (b) Cp comprises an amino acid sequence with at least 92% sequence identity to SEQ ID NO:WSGR Docket No. 69143-718.60130; (c) CHI domain comprises an amino acid sequence with at least 92% sequence identity to SEQ ID NO: 36; or (d) CL domain comprises an amino acid sequence with at least 92% sequence identity to SEQ ID NO: 37. In some embodiments, (a) Cacomprises an amino acid sequence with at least 92% sequence identity to SEQ ID NO: 31; (b) Cp comprises an amino acid sequence with at least 92% sequence identity’ to SEQ ID NO: 30; (c) CHI domain comprises an amino acid sequence with at least 92% sequence identity to SEQ ID NO: 36; and (d) CL domain comprises an amino acid sequence with at least 92% sequence identity to SEQ ID NO: 37. In some embodiments, (a) Cacomprises an amino acid sequence with at least 93% sequence identity to SEQ ID NO: 31; (b) Cp comprises an ammo acid sequence with at least 93% sequence identity to SEQ ID NO: 30; (c) CHI domain comprises an amino acid sequence with at least 93% sequence identity to SEQ ID NO: 36; or (d) CL domain comprises an amino acid sequence with at least 93% sequence identity to SEQ ID NO: 37. In some embodiments, (a) Cαcomprises an amino acid sequence with at least 93% sequence identity to SEQ ID NO: 31; (b) Cβ comprises an amino acid sequence with at least 93% sequence identity to SEQ ID NO: 30; (c) CH1 domain comprises an amino acid sequence with at least 93% sequence identity to SEQ ID NO: 36; and (d) CL domain comprises an amino acid sequence with at least 93% sequence identity to SEQ ID NO: 37. In some embodiments, (a) Cacomprises an amino acid sequence with at least 94% sequence identity to SEQ ID NO: 31; (b) Cp comprises an amino acid sequence with at least 94% sequence identity to SEQ ID NO: 30; (c) CHI domain comprises an amino acid sequence with at least 94% sequence identity to SEQ ID NO: 36; or (d) CL domain comprises an amino acid sequence with at least 94% sequence identity to SEQ ID NO: 37. In some embodiments, (a) Cacomprises an amino acid sequence with at least 94% sequence identity’ to SEQ ID NO: 31; (b) Cp comprises an amino acid sequence with at least 94% sequence identity to SEQ ID NO: 30; (c) CHI domain comprises an amino acid sequence with at least 94% sequence identity to SEQ ID NO: 36; and (d) CL domain comprises an amino acid sequence with at least 94% sequence identity to SEQ ID NO: 37. In some embodiments, (a) Cacomprises an amino acid sequence with at least 95% sequence identity to SEQ ID NO: 31; (b) Cp comprises an ammo acid sequence with at least 95% sequence identity to SEQ ID NO: 30; (c) CHI domain comprises an amino acid sequence with at least 95% sequence identity to SEQ ID NO: 36; or (d) CL domain comprises an amino acid sequence with at least 95% sequence identity to SEQ ID NO: 37. In some embodiments, (a) Cacomprises an amino acid sequence with at least 95% sequence identity to SEQ ID NO: 31; (b) Cp comprises an amino acid sequence with at least 95% sequence identity to SEQ ID NO: 30; (c) CHI domain comprises an amino acid sequence with at least 95% sequence identity to SEQ ID NO: 36; and (d) CL domain comprises an amino acid sequence with at least 95% sequence identity' to SEQ ID NO: 37. In some embodiments, (a) Cacomprises an amino acid sequence with at least 96% sequence identity to SEQ ID NO: 31; (b) Cp comprises an amino acid sequence with at least 96% sequence identity to SEQ ID NO: 30; (c) CHI domain comprises an amino acid sequence with at least 96% sequence identity to SEQ ID NO: 36; or (d) CL domain comprises an amino acid sequence with at least 96% sequence identity to SEQ ID NO: 37. In some embodiments, (a) Cacomprises an amino acid sequence with at least 96% sequence identity’ to SEQ ID NO: 31; (b) Cp comprises an amino acid sequence with at least 96% sequence identity to SEQ ID NO: 30; (c) CHI domain comprises an amino acid sequence with at least 96% sequence identity to SEQ IDWSGR Docket No. 69143-718.601NO: 36; and (d) CL domain comprises an amino acid sequence with at least 96% sequence identity to SEQ ID NO: 37. In some embodiments, (a) Cacomprises an amino acid sequence with at least 97% sequence identity to SEQ ID NO: 31; (b) Cp comprises an amino acid sequence with at least 97% sequence identity to SEQ ID NO: 30; (c) CHI domain comprises an amino acid sequence with at least 97% sequence identity to SEQ ID NO: 36; or (d) CL domain comprises an amino acid sequence with at least 97% sequence identity to SEQ ID NO: 37. In some embodiments, (a) Cacomprises an amino acid sequence with at least 97% sequence identity to SEQ ID NO: 31; (b) Cp comprises an amino acid sequence with at least 97% sequence identity’ to SEQ ID NO: 30; (c) CHI domain comprises an amino acid sequence with at least 97% sequence identity to SEQ ID NO: 36; and (d) CL domain comprises an amino acid sequence with at least 97% sequence identity to SEQ ID NO: 37. In some embodiments, (a) Cacomprises an amino acid sequence with at least 98% sequence identity' to SEQ ID NO: 31; (b) Cp comprises an amino acid sequence with at least 98% sequence identity to SEQ ID NO: 30; (c) CHI domain comprises an amino acid sequence with at least 98% sequence identity to SEQ ID NO: 36; or (d) CL domain comprises an amino acid sequence with at least 98% sequence identity to SEQ ID NO: 37. In some embodiments, (a) Cacomprises an amino acid sequence with at least 98% sequence identity' to SEQ ID NO: 31; (b) Cp comprises an amino acid sequence with at least 98% sequence identity to SEQ ID NO: 30; (c) CHI domain comprises an amino acid sequence with at least 98% sequence identity to SEQ ID NO: 36; and (d) CL domain comprises an amino acid sequence with at least 98% sequence identity to SEQ ID NO: 37. In some embodiments, (a) Cacomprises an amino acid sequence with at least 99% sequence identity to SEQ ID NO: 31; (b) Cp comprises an amino acid sequence with at least 99% sequence identity to SEQ ID NO: 30; (c) CHI domain comprises an amino acid sequence with at least 99% sequence identity to SEQ ID NO: 36; or (d) CL domain comprises an amino acid sequence with at least 99% sequence identity to SEQ ID NO: 37. In some embodiments, (a) Cacomprises an amino acid sequence with at least 99% sequence identity to SEQ ID NO: 31; (b) Cp comprises an amino acid sequence with at least 99% sequence identity’ to SEQ ID NO: 30; (c) CHI domain comprises an amino acid sequence with at least 99% sequence identity to SEQ ID NO: 36; and (d) CL domain comprises an amino acid sequence with at least 99% sequence identity' to SEQ ID NO: 37. In some embodiments, (a) Cacomprises the amino acid sequence of SEQ ID NO: 31; (b) Cp comprises the amino acid sequence of SEQ ID NO: 30; (c) CHI domain comprises the ammo acid sequence of SEQ ID NO: 36; or (d) CL domain comprises the amino acid sequence of SEQ ID NO: 37. In some embodiments, (a) Cacomprises the amino acid sequence of SEQ ID NO: 31; (b) Cp comprises the amino acid sequence of SEQ ID NO: 30; (c) CH1 domain comprises the amino acid sequence of SEQ ID NO: 36; and (d) CL domain comprises the amino acid sequence of SEQ ID NO: 37. In some embodiments, (a) the C1Hcomprises the amino acid sequence of SEQ ID NO: 30; (b) the C1Lcomprises the amino acid sequence of SEQ ID NO: 31; (c) the C2Hcomprises the amino acid sequence of SEQ ID NO: 30; (d) the C2Lcomprises the amino acid sequence of SEQ ID NO: 31; (e) the C3Hcomprises the amino acid sequence of SEQ ID NO: 36; or (f) the C3Lcomprises the amino acid sequence of SEQ ID NO: 37. In some embodiments, (a) the C1Hcomprises the amino acid sequence of SEQ ID NO: 30; (b) the C1Lcomprises the amino acid sequence of SEQ ID NO: 31; (c) the C2Hcomprises the amino acid sequence of SEQ ID NO: 30; (d) the C2Lcomprises the aminoWSGR Docket No. 69143-718.601acid sequence of SEQ ID NO: 31; (e) the C3Hcomprises the amino acid sequence of SEQ ID NO: 36; and (f) the C3Lcomprises the amino acid sequence of SEQ ID NO: 37. In some embodiments, (a) the C1Hcomprises the amino acid sequence of SEQ ID NO: 31; (b) the C1Lcomprises the amino acid sequence of SEQ ID NO: 30; (c) the C2Hcomprises the amino acid sequence of SEQ ID NO: 31; (d) the C2Lcomprises the amino acid sequence of SEQ ID NO: 30; (e) the C3Hcomprises the amino acid sequence of SEQ ID NO: 36; or (f) the C3Lcomprises the amino acid sequence of SEQ ID NO: 37. In some embodiments, (a) the C1Hcomprises the amino acid sequence of SEQ ID NO: 31; (b) the C1Lcomprises the amino acid sequence of SEQ ID NO: 30; (c) the C2Hcomprises the amino acid sequence of SEQ ID NO: 31; (d) the C2Lcomprises the amino acid sequence of SEQ ID NO: 30; (e) the C3Hcomprises the amino acid sequence of SEQ ID NO: 36; and (f) the C3Lcomprises the amino acid sequence of SEQ ID NO: 37.

[0073] In some embodiments, (a) the CD19VH is covalently linked to the C1Hdirectly or via a peptide linker; (b) the CD19VL is covalently linked to the C1Ldirectly or via a peptide linker; (c) the CD3VH is covalently linked to the C2Hdirectly or via a peptide linker; (d) the CD3VL is covalently linked to the C2Ldirectly or via a peptide linker; (e) the CD20VH is covalently linked to the C3Hdirectly or via a peptide linker; or (f) the CD20VL is covalently linked to the C3Ldirectly or via a peptide linker. In some embodiments, (a) the CD19VH is covalently linked to the C1Hdirectly or via a peptide linker; (b) the CD19VL is covalently linked to the C1Ldirectly or via a peptide linker; (c) the CD3VH is covalently linked to the C2Hdirectly or via a peptide linker; (d) the CD3VL is covalently linked to the C2Ldirectly or via a peptide linker; (e) the CD20VH is covalently linked to the C3Hdirectly or via a peptide linker; and (f) the CD20VL is covalently linked to the C3Ldirectly or via a peptide linker. In some embodiments, (a) the CD19VH is covalently linked to the C1Hdirectly; (b) the CD19VL is covalently linked to the C1Ldirectly; (c) the CD3VH is covalently linked to the C2Hdirectly; (d) the CD3VL is covalently linked to the C2Ldirectly; (e) the CD20VH is covalently linked to the C3Hdirectly; or (f) the CD20VL is covalently linked to the C3Ldirectly. In some embodiments, (a) the CD19VH is covalently linked to the C1Hdirectly; (b) the CD19VL is covalently linked to the C1Ldirectly; (c) the CD3VH is covalently linked to the C2Hdirectly; (d) the CD3VL is covalently linked to the C2Ldirectly; (e) the CD20VH is covalently linked to the C3Hdirectly; and (f) the CD20VL is covalently linked to the C3Ldirectly. In some embodiments, (a) the CD19VH is covalently linked to the C1Hvia a peptide linker; (b) the CD19VL is covalently linked to the C1Lvia a peptide linker; (c) the CD3VH is covalently linked to the C2Hvia a peptide linker; (d) the CD3VL is covalently linked to the C2Lvia a peptide linker; (e) the CD20VH is covalently linked to the C3Hvia a peptide linker; or (f) the CD20VL is covalently linked to the C3Lvia a peptide linker. In some embodiments, (a) the CD19VH is covalently linked to the C1Hvia a peptide linker; (b) the CD19VL is covalently linked to the C1Lvia a peptide linker; (c) the CD3VH is covalently linked to the C2Hvia a peptide linker; (d) the CD3VL is covalently linked to the C2Lvia a peptide linker; (e) the CD20VH is covalently linked to the C3Hvia a peptide linker; and (f) the CD20VL is covalently linked to the C3Lvia a peptide linker.

[0074] In some embodiments, the antibody or antigen-binding portion thereof further comprises a first heavy chain (HC1), a second heavy chain (HC2), a first light chain (LCI), a second light chain (LC2), or a third light chain (LC3). In some embodiments, the antibody or antigen -binding portion thereof furtherWSGR Docket No. 69143-718.601comprising the first heavy chain (HC 1 ), the second heavy chain (HC2), the first light chain (LC 1 ), the second light chain (LC2), and the third light chain (LC3). In some embodiments, the antibody or antigen-binding portion thereof further comprises a fragment cry stallizable (Fc) region. In some embodiments, the antibody or antigen -binding portion thereof further comprises an immunoglobulin (Ig) G, IgA, IgM, IgE, or IgD. In some embodiments, the antibody or antigen-binding portion thereof further comprises an IgG. In some embodiments, the antibody or antigen-binding portion thereof further comprises an IgA. In some embodiments, the antibody or antigen-binding portion thereof further comprises an IgM. In some embodiments, the antibody or antigen-binding portion thereof further comprises an IgE. In some embodiments, the antibody or antigen-binding portion thereof further comprises an IgD. In some embodiments, the antibody or antigen -binding portion thereof further comprises an IgGl, IgG2, IgG3, or IgG4. In some embodiments, the antibody or antigen -binding portion thereof further comprises an IgGl. In some embodiments, the antibody or antigen-binding portion thereof further comprises an IgG2. In some embodiments, the antibody or antigen -binding portion thereof further comprises an IgG3. In some embodiments, the antibody or antigen -binding portion thereof further comprises an IgG4. In some embodiments, the antibody or antigen -binding portion thereof further comprises a human IgGl, IgG2, IgG3, or IgG4. In some embodiments, the antibody or antigen-binding portion thereof further comprises a human IgGl. In some embodiments, the antibody or antigen-binding portion thereof further comprises a human IgG2. In some embodiments, the antibody or antigen -binding portion thereof further comprises a human IgG3. In some embodiments, the antibody or antigen-binding portion thereof further comprises a human IgG l In some embodiments, the GDI ) binding moiety, the CD3 binding moiety’, or the CD20 binding moiety comprises a fragment antigen -binding (Fab) region, a Fab’, a F(ab’)2, or single chain variable fragment (scFv). In some embodiments, the CD19 binding moiety, the CD3 binding moiety, or the CD20 binding moiety comprises a single chain variable fragment (scFv). In some embodiments, the CD19 binding moiety, the CD3 binding moiety, or tire CD20 binding moiety comprises a Fab’. In some embodiments, the CD 19 binding moiety, the CD3 binding moiety, or the CD20 binding moiety comprises a F(ab’)2. In some embodiments, the CD 19 binding moiety, tire CD3 binding moiety, or the CD20 binding moiety comprises a Fab region. In some embodiments, the CD 19 binding moiety, the CD3 binding moiety, and the CD20 binding moiety each comprises a Fab region.

[0075] In some embodiments, HC1, HC2, LC1, LC2 and LC3 comprise domains operably linked, from the amino terminus to the carboxyl terminus, in the following formats: (a) CD19VH-Cp-CD3VL-Ca-Fc, CD2OVH-CH1-Fc, CD19VL-Cα, CD3VH-Cβ, and CD20VL-CL, respectively; (b) CD19VL-Cα-CD3VH-Cβ-Fc, CD20VH-CH1-Fc, CD19VH-Cβ, CD3VL-Cα, and CD20VL-CL, respectively; (c) CD3VH-Cβ-CD19VL-Cα-Fc, CD20VH-CH1-Fc, CD3VL-Cα, CD19VH-Cβ, and CD20VL-CL, respectively; or (d) CD3VL-Cα-CD19VH-Cβ-Fc, CD20VH-CH1-Fc, CD3VH-Cβ, CD19VL-Cα, and CD20VL-CL, respectively. In some embodiments, HC1, HC2, LC1, LC2 and LC3 comprise domains operably linked, from the amino terminus to the carboxyl terminus, in the following formats: CD19VH-Cp-CD3 VL-Ca-Fc, CD2OVH-CH1-Fc, CD19VL-Cα, CD3VH-Cβ, and CD20VL-CL, respectively. In some embodiments, (a) CD19VH-Cβ is covalently linked to CD3VL-Cα-Fc directly or via a peptide linker; (b) CD19VL-Cαis covalently linked to CD3VH-Cβ-Fc directly or via a peptide linker; (c) CD3 VH-Cp is covalently linked toWSGR Docket No. 69143-718.601CD19VL-Ca-Fc directly or via a peptide linker; or (d) CD3VL-Cα is covalently linked to CD19VH-Cβ-Fc directly or via a peptide linker. In some embodiments. CD19VH-Cp is covalently linked to CD3VL-Ca-Fc directly. In some embodiments, CD19VH-Cp is covalently linked to CD3VL-Ca-Fc via the peptide linker. In some embodiments, the peptide linker comprises 1 to 40 amino acids in length. In some embodiments, the peptide liner comprises 1 amino acid in length, 2 amino acids in length, 3 amino acids in length, 4 amino acids in length, 5 amino acids in length, 6 amino acids in length, 7 amino acids in length, 8 amino acids in length, 9 amino acids in length, 10 amino acids in length, 11 amino acids in length, 12 amino acids in length, 13 amino acids in length, 14 amino acids in length, 15 amino acids in length, 16 ammo acids in length, 17 amino acids in length, 18 amino acids in length, 19 amino acids in length, 20 amino acids in length, 21 amino acids in length, 22 amino acids in length, 23 amino acids in length, 24 amino acids in length, 25 amino acids in length, 26 amino acids in length, 27 amino acids in length, 28 amino acids in length, 29 amino acids in length, 30 amino acids in length, 31 amino acids in length, 32 amino acids in length, 33 amino acids in length, 34 amino acids in length, 35 amino acids in length, 36 amino acids in length, 37 amino acids in length, 38 amino acids in length, 39 amino acids in length, or 40 amino acids in length. In some embodiments, the peptide linker comprises glycine (G) and serine (S). In some embodiments, the peptide linker comprises a glycine (G) and serine (S) linker comprising (GS)n (SEQ ID NO: 46), (GGS)n (SEQ ID NO: 47), (GGGS)n (SEQ ID NO: 48), (GGGGS)n (SEQ ID NO: 49), (GGSG)n (SEQ ID NO: 50), (GGGSS)n (SEQ ID NO: 51), and n is an integer of 1-9. In some embodiments, the peptide linker comprises a glycine (G) and serine (S) linker comprising (GS)n (SEQ ID NO: 46), and n is an integer of 1-9. In some embodiments, the peptide linker comprises a glycine (G) and serine (S) linker comprising (GGS)n (SEQ ID NO: 47), and n is an integer of 1-9. In some embodiments, the peptide linker comprises a glycine (G) and serine (S) linker comprising (GGGS)n (SEQ ID NO: 48), and n is an integer of 1-9. In some embodiments, the peptide linker comprises a glycine (G) and serine (S) linker comprising (GGGGS)n (SEQ ID NO: 49), and n is an integer of 1-9. In some embodiments, the peptide linker comprises a glycine (G) and serine (S) linker comprising (GGSG)n (SEQ ID NO: 50), and n is an integer of 1-9. In some embodiments, the peptide linker comprises a glycine (G) and serine (S) linker comprising (GGGSS)n (SEQ ID NO: 51), and n is an integer of 1-9, and n is an integer of 1-9. In some embodiments, n is an integer of 1, 2, 3, 4, 5, 6, 7, 8, or 9. In some embodiments, the peptide linker comprises SEQ ID NO: 34. In some embodiments, CD19VH-Cp is covalently linked to CD3VL-Ca-Fc via the peptide linker comprising SEQ ID NO: 34. In some embodiments, (a) CD19VH-Cp-CD3VL-Cais covalently linked to the Fc region directly, via a hinge region, or via a E / K coil linker; (b) CD20VH-CHI is covalently linked to the Fc region directly, via a hinge region, or via a E / K coil linker; (c) CD19VL-Cα-CD3VH-Cβ is covalently linked to the Fc region directly, via a hinge region, or via a E / K coil linker; (d) CD3VH-Cβ-CD19VL-Cα is covalently linked to the Fc region directly, via a hinge region, or via a E / K coil linker; or (e) CD3VL-Ca-CD19VH-Cp is covalently linked to the Fc region directly, via a hinge region or via a E / K coil linker. In some embodiments, CD19VH-Cp-CD3VL-Cais covalently linked to the Fc region via the hinge region or via a E / K coil linker. In some embodiments, CD20VH-CHI is covalently linked to the Fc region via the hinge region or via a E / K coil linker. In some embodiments, (a) CD19VH-Cp-CD3VL-Cais covalently linked to the Fc region via the hinge region or via a E / K coil linker;WSGR Docket No. 69143-718.601and (b) CD20VH-CH1 is covalently linked to the Fc region via the hinge region or via a E / K coil linker. In some embodiments, (a) CD19VH-Cp-CD3VL-Ca is covalently linked to the Fc region via the hinge region or via a E / K coil linker; or (b) CD20VH-CH1 is covalently linked to the Fc region via the hinge region or via a E / K coil linker. In some embodiments, the hinge region comprises SEQ ID NO: 33, In some embodiments, CD19VH-Cp-CD3VL-Cais covalently linked to the Fc region via the hinge region comprising SEQ ID NO: 33. In some embodiments, CD20VH-CH1 is covalently linked to the Fc region via the hinge region comprising SEQ ID NO: 33. In some embodiments, (a) CD19VH-Cp-CD3VL-Cais covalently linked to the Fc region via the hinge region comprising SEQ ID NO: 33; and (b) CD20VH-CH1 is covalently linked to the Fc region via the hinge region comprising SEQ ID NO: 33. In some embodiments, (a) CD19VH-Cp-CD3VL-Cais covalently linked to the Fc region via the hinge region comprising SEQ ID NO: 33; or (b) CD20VH-CH1 is covalently linked to the Fc region via the hinge region comprising SEQ ID NO: 33, In some embodiments, the E / K coil linker comprises an amino acid glutamate (E). In some embodiments, the E / K coil linker comprises an amino acid lysine (K).|0076] In some embodiments, (a) CD19VH-Cp associates with CD19VL-Cato form the CD 19 binding moiety; (b) CD3VL-Caassociates with CD3 VH-Cp to form the CD3 binding moiety; (c) CD20VH-CH1 associates with CD20VL-CL to form the CD20 binding moiety; (d) CD19VL-Caassociates with CD19VH-Cp to form the CD 19 binding moiety; or (e) CD3 VH-Cp associates with CD3VL-Cato form the CD3 binding moiety. In some embodiments, (a) CD 19 VH-Cp associates with CD19VL-Cato form the CD19 binding moiety; (b) CD3VL-Caassociates with CD3VH-Cp to form the CD3 binding moiety; (c) CD20VH-CH1 associates with CD20VL-CL to form the CD20 binding moiety’; (d) CD19VL-Caassociates with CD19VH-Cpto form the CD19 binding moiety; and (e) CD3VH-Cp associates with CD3 VL-Cato form the CD3 binding moiety. In some embodiments, (a) CD 19VH-Cp associates with CD19VL-Cato form the CD19 binding moiety; (b) CD3VL-Caassociates with CD3VH-Cp to form the CD3 binding moiety; and (c) CD20VH-CH1 associates with CD20VL-CL to form the CD20 binding moiety. In some embodiments, (a) CD19VH-Cp associates with CD19VL-Cato form the CD 19 binding moiety; (b) CD3VL-Caassociates with CD3VH-Cp to form the CD3 binding moiety; or (c) CD20VH-CH1 associates with CD20VL-CL to form the CD20 binding moiety.

[0077] In some embodiments, Caand Cp associate to form a dimer via a bond or an interaction between Caand Cp. In some embodiments, Caor Cp comprises an amino acid modification that results in a disulfide bond formed between Ctand Cp, and the disulfide bond improves the stability of the interface between Ca and Cp. in some embodiments, the Fc region of the antibody or antigen-binding portion thereof comprises a first amino acid mutation that reduces or eliminates antibody-dependent cellular cytotoxicity (ADCC), complement-dependent cytotoxicity (CDC) or binding of the antibody or antigenbinding portion thereof to a Fc-gamma receptor (FcyR). In some embodiments, the Fc region of tire antibody or antigen-binding portion thereof comprises a first amino acid mutation that reduces or eliminates antibody-dependent cellular cytotoxicity (ADCC), antibody-dependent cellular phagocytosis (ADCP), or complement-dependent cytotoxicity (CDC) and binding of the antibody or antigen -binding portion thereof to a Fc-gamma receptor (FcyR). In some embodiments, the first amino acid mutation comprises a substitution of phenylalanine (F) with alanine (A) at amino acid 234 according to the EUWSGR Docket No. 69143-718.601numbering (F234A). In some embodiments, the first amino acid mutation comprises a substitution of leucine (L) with alanine (A) at amino acid 235 according to the EU numbering (L235A). in some embodiments, the first amino acid mutation comprises F234A and L235A. In some embodiments, the Fc region of the first heavy chain (HC1) comprises the first amino acid mutation comprising F234A and L235A. In some embodiments, the Fc region of the second heavy chain (HC2) comprises the first amino acid mutation comprising F234A and L235A. In some embodiments, the Fc region of the first heavy chain (HC 1) comprises the first amino acid mutation comprising F234A and L235A and the Fc region of the second heavy chain (HC2) comprises the first amino acid mutation comprising F234A and L235A.

[0078] In some embodiments, the Fc region of the first heavy chain (HC1) or second heavy chain (HC2) comprises a second amino acid mutation that results in knob-into-hole substitution in the first heavy chain (HC1) or second heavy chain (HC2). In some embodiments, the Fc region of the first heavy chain (HC1) and second heavy chain (HC2) each comprises a second amino acid mutation that results in knob-into-hole substitution in the first heavy chain (HC1) and second heavy chain (HC2). In some embodiments, the second amino acid mutation of the Fc region comprises: (a) a substitution of serine (S) w ith cy steine (C) at amino acid residue 354 according to the EU numbering (S354C); (b) a substitution of threonine (T) with tryptophan (W) at amino acid residue 366 according to the EU numbering (T366W); (c) a substitution of tyrosine (Y) with cysteine (C) at amino acid residue 349 according to the EU numbering (Y349C); (d) a substitution of threonine (T) with serine (S) at amino acid residue 366 according to the EU numbering (T366S); (e) a substitution of leucine (L) w ith alanine (A) at amino acid residue 368 according to the EU numbering (L368A); or (f) a substitution of tyrosine (Y) with valine (V) at amino acid residue 407 according to the EU numbering (Y 407V). In some embodiments, the second amino acid mutation of the Fc region comprises S354C, T366W, Y349C, T366S, L368A, and Y407V. In some embodiments, the second amino acid mutation of the Fc region comprises S354C. In some embodiments, the second amino acid mutation of the Fc region comprises T366W. In some embodiments, the second amino acid mutation of the Fc region comprises Y349C. In some embodiments, the second amino acid mutation of the Fc region comprises T366S. In some embodiments, the second amino acid mutation of the Fc region comprises L368A. In some embodiments, the second amino acid mutation of the Fc region comprises Y407V. In some embodiments, (a) the Fc region of the first heavy chain (HC1) comprises the second amino acid mutation comprising Y349C, T366S, L368A, or Y407V; or (b) the Fc region of the second heavy chain (IIC2) comprises the second amino acid mutation comprising S354C or T366W. In some embodiments, (a) the Fc region of the first heavy chain (HC1) comprises the second amino acid mutation comprising S354C or T366W; and (b) the Fc region of the second heavy chain (HC2) comprises the second amino acid mutation comprising Y349C, T366S, L368A, or Y407V. In some embodiments, (a) the Fc region of the first heavy chain (HC 1) comprises the second amino acid mutation comprising Y349C, T366S, L368A, or Y407V; and (b) the Fc region of the second heavy chain (HC2) comprises the second amino acid mutation comprising S354C or T366W. In some embodiments, (a) the Fc region of the first heavy chain (HC1) comprises the second ammo acid mutation comprising S354C and T366W; and (b) the Fc region of the second heavy chain (HC2) comprises the second amino acid mutation comprising Y349C, T366S, L368A, and Y407V. In some embodiments, (a) the Fc region of the first heavy chain (HC1)WSGR Docket No. 69143-718.601comprises the second amino acid mutation comprising Y349C, T366S, L368A, and Y407V; and (b) the Fc region of the second heavy chain (HC2) comprises the second amino acid mutation comprising S354C and T366W. In some embodiments, (a) the Fc region of the first heavy chain (HCI) comprises the first amino acid mutation comprising F234A and L235A and the second amino acid mutation comprising S354C and T366W; and (b) the Fc region of the second heavy chain (HC2) comprises the first amino acid mutation comprising F234A and L235A and the second amino acid mutation comprising Y349C, T366S, L368A, and Y407V. In some embodiments, (a) the Fc region of the first heavy chain (HCI) comprises the first amino acid mutation comprising F234A and L235A and the second amino acid mutation comprising Y349C, T366S, L368A, and Y407V; and (b) the Fc region of the second heavy chain (HC2) comprises the first amino acid mutation comprising F234A and L235A and the second amino acid mutation comprising S354C and T366W. In some embodiments, the Fc region of the first heavy chain (HCI) or second heavy chain (HC2) comprises a third amino acid mutation comprising: (a) a substitution of serine (S) with proline (P) at amino acid residue 228 according to the EU numbering (S228P); (b) a substitution of methionine (M) with tyrosine (Y) at amino acid residue 252 according to the EU numbering (M252Y); (c) a substitution of serine (S) with threonine (T) at amino acid residue 254 according to the EU numbering (S254T); or (d) a substitution of threonine (T) with glutamic acid (E) at amino acid residue 256 according to the EU numbering (T256E). In some embodiments, the Fc region of the first heavy chain (HCI ) or second heavy chain (HC2) comprises a third amino acid mutation comprising S228P, M252Y, S254T and T256E. In some embodiments, the Fc region of the first heavy chain (HCI) comprises a third amino acid mutation comprising S228P, M252Y, S254T, or T256E. In some embodiments, the Fc region of the first heavy chain (HCI) comprises a third amino acid mutation comprising S228P. In some embodiments, the Fc region of the first heavy chain (HCI) comprises a third amino acid mutation comprising M252Y. In some embodiments, tlie Fc region of the first heavy chain (HCI) comprises a third amino acid mutation comprising S254T. In some embodiments, the Fc region of the first heavy chain (HCI) comprises a third amino acid mutation comprising T256E. In some embodiments, the Fc region of the second heavy chain (HC 1 ) comprises a third amino acid mutation comprising S228P, M252Y, S254T, or T256E. In some embodiments, the Fc region of the second heavy chain (HCI) comprises a third amino acid mutation comprising S228P. In some embodiments, the Fc region of the second heavy chain (HCI) comprises a third ammo acid mutation comprising M252Y. In some embodiments, the Fc region of the second heavy chain (HCI) comprises a third amino acid mutation comprising S254T. In some embodiments, the Fc region of the second heavy chain (HCI) comprises a third amino acid mutation comprising T256E.

[0079] In some embodiments, the Fc region of the first heavy chain (HC 1) comprises an amino acid sequence with about 70% to about 100% sequence identity to SEQ ID NO: 32, e.g., about 70%, 71%, 72%, 73%, 74%, 75%, 76%. 77%, 78%, 79%, 80%, 81%, 82%. 83%, 84%, 85%. 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or about 100% sequence identity, or any percentage there between. In some embodiments, the Fc region of the second heavy chain (HC2) comprises an amino acid sequence with about 70% to about 100% sequence identity to SEQ ID NO: 35, e.g., about 70%, 71%, 72%, 73%, 74%, 75%, 76%, 77%, 78%, 79%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or about 100% sequenceWSGR Docket No. 69143-718.601identity, or any percentage there between. In some embodiments, (a) the Fc region of the first heavy chain (HCI) comprises an amino acid sequence with at least 70% sequence identity to SEQ ID NO: 32; or (b) the Fc region of the second heavy chain (HC2) comprises an amino acid sequence with at least 70% sequence identity to SEQ ID NO: 35. In some embodiments, (a) the Fc region of the first heavy chain (HCI) comprises an amino acid sequence with at least 70% sequence identity to SEQ ID NO: 32; and (b) the Fc region of the second heavy chain (HC2) comprises an amino acid sequence with at least 70% sequence identity to SEQ ID NO: 35. In some embodiments, (a) the Fc region of the first heavy chain (HC1) comprises an amino acid sequence with at least 75% sequence identity to SEQ ID NO: 32; or (b) the Fc region of the second heavy chain (HC2) comprises an amino acid sequence with at least 75% sequence identity to SEQ ID NO: 35. In some embodiments, (a) the Fc region of the first heavy chain (HC1) comprises an amino acid sequence with at least 75% sequence identity to SEQ ID NO: 32; and (b) the Fc region of the second heavy chain (HC2) comprises an amino acid sequence with at least 75% sequence identity to SEQ ID NO: 35. In some embodiments, (a) tire Fc region of the first heavy chain (HC1) comprises an amino acid sequence with at least 80% sequence identity to SEQ ID NO: 32; or (b) the Fc region of the second heavy chain (HC2) comprises an amino acid sequence with at least 80% sequence identity to SEQ ID NO: 35. In some embodiments, (a) the Fc region of the first heavy chain (HCI) comprises an amino acid sequence with at least 80% sequence identity to SEQ ID NO: 32; and (b) the Fc region of the second heavy chain (HC2) comprises an amino acid sequence with at least 80% sequence identity to SEQ ID NO: 35. In some embodiments, (a) the Fc region of the first heavy chain (HC1) comprises an amino acid sequence with at least 85% sequence identity to SEQ ID NO: 32; or (b) the Fc region of the second heavy chain (HC2) comprises an amino acid sequence with at least 85% sequence identity to SEQ ID NO: 35. In some embodiments, (a) the Fc region of the first heavy chain (HC1) comprises an amino acid sequence with at least 85% sequence identity to SEQ ID NO: 32; and (b) the Fc region of the second heavy chain (HC2) comprises an amino acid sequence with at least 85% sequence identity to SEQ ID NO: 35. In some embodiments, (a) the Fc region of the first heavy chain (HCI) comprises an amino acid sequence with at least 86% sequence identity to SEQ ID NO: 32; or (b) the Fc region of the second heavy chain (HC2) comprises an amino acid sequence with at least 86% sequence identity to SEQ ID NO: 35. In some embodiments, (a) the Fc region of the first heavy chain (HC1) comprises an amino acid sequence with at least 86% sequence identity to SEQ ID NO: 32; and (b) the Fc region of the second heavy chain (HC2) comprises an amino acid sequence with at least 86% sequence identity to SEQ ID NO: 35. In some embodiments, (a) the Fc region of the first heavy chain (HC 1) comprises an amino acid sequence with at least 87% sequence identity to SEQ ID NO: 32; or (b) the Fc region of the second heavy chain (HC2) comprises an amino acid sequence with at least 87% sequence identity to SEQ ID NO: 35. In some embodiments, (a) the Fc region of the first heavy chain (HCI) comprises an amino acid sequence with at least 87% sequence identity to SEQ ID NO: 32; and (b) the Fc region of the second heavy chain (HC2) comprises an amino acid sequence with at least 87% sequence identity to SEQ ID NO: 35. In some embodiments, (a) the Fc region of the first heavy chain (HCI) comprises an amino acid sequence with at least 88% sequence identity to SEQ ID NO: 32; or (b) the Fc region of the second heavy chain (HC2) comprises an amino acid sequence with at least 88%WSGR Docket No. 69143-718.601sequence identity to SEQ ID NO: 35. In some embodiments, (a) the Fc region of the first heavy chain (HC1) comprises an amino acid sequence with at least 88% sequence identity to SEQ ID NO: 32; and (b) the Fc region of the second heavy chain (HC2) comprises an amino acid sequence with at least 88% sequence identity to SEQ ID NO: 35. In some embodiments, (a) the Fc region of the first heavy chain (HCI) comprises an amino acid sequence with at least 89% sequence identity to SEQ ID NO: 32; or (b) the Fc region of the second heavy chain (HC2) comprises an amino acid sequence with at least 89% sequence identity to SEQ ID NO: 35. In some embodiments, (a) the Fc region of the first heavy chain (HC1) comprises an amino acid sequence with at least 89% sequence identity to SEQ ID NO: 32; and (b) the Fc region of the second heavy chain (HC2) comprises an amino acid sequence with at least 89% sequence identity to SEQ ID NO: 35. In some embodiments, (a) the Fc region of the first heavy chain (HC1) comprises an amino acid sequence with at least 90% sequence identity to SEQ ID NO: 32; or (b) the Fc region of the second heavy chain (HC2) comprises an amino acid sequence with at least 90% sequence identity to SEQ ID NO: 35. In some embodiments, (a) the Fc region of the first heavy chain (HC1) comprises an amino acid sequence with at least 90% sequence identity to SEQ ID NO: 32; and (b) the Fc region of the second heavy chain (HC2) comprises an amino acid sequence with at least 90% sequence identity to SEQ ID NO: 35. In some embodiments, (a) the Fc region of the first heavy chain (HCI) comprises an amino acid sequence with at least 91% sequence identity to SEQ ID NO: 32; or (b) the Fc region of the second heavy chain (HC2) comprises an amino acid sequence with at least 91% sequence identity to SEQ ID NO: 35. In some embodiments, (a) the Fc region of the first heavy chain (HCI) comprises an amino acid sequence with at least 91% sequence identity to SEQ ID NO: 32; and (b) the Fc region of the second heavy chain (HC2) comprises an amino acid sequence with at least 91% sequence identity to SEQ ID NO: 35. In some embodiments, (a) tire Fc region of the first heavy chain (HCI) comprises an amino acid sequence with at least 92% sequence identity to SEQ ID NO: 32; or (b) the Fc region of the second heavy chain (HC2) comprises an amino acid sequence with at least 92% sequence identity to SEQ ID NO: 35. In some embodiments, (a) the Fc region of the first heavy chain (HCI) comprises an amino acid sequence with at least 92% sequence identity to SEQ ID NO: 32; and (b) the Fc region of the second heavy chain (HC2) comprises an amino acid sequence with at least 92% sequence identity to SEQ ID NO: 35. In some embodiments, (a) the Fc region of the first heavy chain (HCI) comprises an amino acid sequence with at least 93% sequence identity to SEQ ID NO: 32; or (b) the Fc region of the second heavy chain (HC2) comprises an amino acid sequence with at least 93% sequence identity to SEQ ID NO: 35. In some embodiments, (a) the Fc region of the first heavy chain (HC 1) comprises an amino acid sequence with at least 93% sequence identity to SEQ ID NO: 32; and (b) the Fc region of the second heavy chain (HC2) comprises an amino acid sequence with at least 93% sequence identity to SEQ ID NO: 35. In some embodiments, (a) the Fc region of the first heavy chain (HCI) comprises an amino acid sequence with at least 94% sequence identity to SEQ ID NO: 32; or (b) the Fc region of the second heavy chain (HC2) comprises an amino acid sequence with at least 94% sequence identity to SEQ ID NO: 35. In some embodiments, (a) the Fc region of the first heavy chain (HCI) comprises an amino acid sequence with at least 94% sequence identity to SEQ ID NO: 32; and (b) the Fc region of the second heavy chain (HC2) comprises an amino acid sequence with at least 94%WSGR Docket No. 69143-718.601sequence identity to SEQ ID NO: 35. In some embodiments, (a) the Fc region of the first heavy chain (HC1) comprises an amino acid sequence with at least 95% sequence identity to SEQ ID NO: 32; or (b) the Fc region of the second heavy chain (HC2) comprises an amino acid sequence with at least 95% sequence identity to SEQ ID NO: 35. In some embodiments, (a) the Fc region of the first heavy chain (HC1) comprises an amino acid sequence with at least 95% sequence identity to SEQ ID NO: 32; and (b) the Fc region of the second heavy chain (HC2) comprises an amino acid sequence with at least 95% sequence identity to SEQ ID NO: 35. In some embodiments, (a) the Fc region of the first heavy chain (HC1) comprises an amino acid sequence with at least 96% sequence identity to SEQ ID NO: 32; or (b) the Fc region of the second heavy chain (HC2) comprises an amino acid sequence with at least 96% sequence identity to SEQ ID NO: 35. In some embodiments, (a) the Fc region of the first heavy chain (HC1) comprises an amino acid sequence with at least 96% sequence identity to SEQ ID NO: 32; and (b) the Fc region of the second heavy chain (HC2) comprises an amino acid sequence with at least 96% sequence identity to SEQ ID NO: 35. In some embodiments, (a) the Fc region of the first heavy chain (HC1) comprises an amino acid sequence with at least 97% sequence identity to SEQ ID NO: 32; or (b) the Fc region of the second heavy chain (HC2) comprises an amino acid sequence with at least 97% sequence identity to SEQ ID NO: 35. In some embodiments, (a) the Fc region of the first heavy chain (HC1) comprises an amino acid sequence with at least 97% sequence identity to SEQ ID NO: 32; and (b) the Fc region of the second heavy chain (HC2) comprises an amino acid sequence with at least 97% sequence identity to SEQ ID NO: 35. In some embodiments, (a) the Fc region of the first heavy chain (HC1) comprises an amino acid sequence with at least 98% sequence identity to SEQ ID NO: 32; or (b) the Fc region of the second heavy chain (HC2) comprises an amino acid sequence with at least 98% sequence identity to SEQ ID NO: 35. In some embodiments, (a) the Fc region of the first heavy chain (HC1) comprises an amino acid sequence with at least 98% sequence identity to SEQ ID NO: 32; and (b) the Fc region of the second heavy chain (HC2) comprises an amino acid sequence with at least 98% sequence identity to SEQ ID NO: 35. In some embodiments, (a) the Fc region of the first heavy chain (HC1) comprises an amino acid sequence with at least 99% sequence identity to SEQ ID NO: 32; or (b) the Fc region of the second heavy chain (HC2) comprises an amino acid sequence with at least 99% sequence identity to SEQ ID NO: 35. In some embodiments, (a) the Fc region of the first heavy chain (HC1) comprises an amino acid sequence with at least 99% sequence identity to SEQ ID NO: 32; and (b) the Fc region of the second heavy chain (HC2) comprises an amino acid sequence with at least 99% sequence identity to SEQ ID NO: 35. In some embodiments, (a) the Fc region of the first heavy chain (HC 1) comprises the amino acid sequence of SEQ ID NO: 32; or (b) the Fc region of the second heavy chain (HC2) comprises the amino acid sequence of SEQ ID NO: 35, In some embodiments, (a) the Fc region of the first heavy chain (HC 1 ) comprises the amino acid sequence of SEQ ID NO: 32; and (b) the Fc region of the second heavy chain (HC2) comprises the amino acid sequence of SEQ ID NO: 35.

[0080] In some embodiments, the HC1 comprises an amino acid sequence with about 70% to about 100% sequence identity to SEQ ID NO: 25, e.g., about 70%, 71%, 72%, 73%, 74%, 75%, 76%, 77%, 78%, 79%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%. 93%, 94%, 95%.96%, 97%, 98%, 99%, or about 100% sequence identity, or any percentage there between. In someWSGR Docket No. 69143-718.601embodiments, the HC2 comprises an amino acid sequence with about 70% to about 100% sequence identity to SEQ ID NO: 26, e.g., about 70%, 71%, 72%, 73%, 74%, 75%, 76%, 77%, 78%, 79%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or about 100% sequence identity, or any percentage there between. In some embodiments, the LC 1 comprises an amino acid sequence with about 70% to about 100% sequence identity to SEQ ID NO: 27, e.g., about 70%, 71%, 72%, 73%, 74%, 75%, 76%, 77%, 78%, 79%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or about 100% sequence identity, or any percentage there between, In some embodiments, the LC2 comprises an amino acid sequence with about 70% to about 100% sequence identity to SEQ ID NO: 28, e.g., about 70%, 71%, 72%, 73%, 74%, 75%, 76%, 77%, 78%, 79%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or about 100% sequence identity, or any percentage there between. In some embodiments, the LC3 comprises an amino acid sequence with about 70% to about 100% sequence identity to SEQ ID NO: 29, e.g., about 70%. 71%, 72%, 73%. 74%, 75%, 76%, 77%, 78%, 79%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or about 100% sequence identity, or any percentage there between.

[0081] In embodiments, (a) the HCl comprises an amino acid sequence with at least 70% sequence identity to SEQ ID NO: 25; (b) HC2 comprises an amino acid sequence with at least 70% sequence identity to SEQ ID NO: 26; (c) LC1 comprises an amino acid sequence with at least 70% sequence identity to SEQ ID NO: 27; (d) LC2 comprises an amino acid sequence with at least 70% sequence identity to SEQ ID NO: 28; or (e) LC3 comprises an amino acid sequence with at least 70% sequence identity to SEQ ID NO: 29. In some embodiments, (a) HCl comprises an amino acid sequence with at least 70% sequence identity to SEQ ID NO: 25; (b) HC2 comprises an amino acid sequence with at least 70% sequence identity to SEQ ID NO: 26; (c) LC1 comprises an amino acid sequence with at least 70% sequence identity to SEQ ID NO: 27; (d) LC2 comprises an amino acid sequence with at least 70% sequence identity to SEQ ID NO: 28; and (e) LC3 comprises an amino acid sequence with at least 70% sequence identity to SEQ ID NO: 29. In embodiments, (a) the HCl comprises an amino acid sequence with at least 75% sequence identity to SEQ ID NO: 25; (b) HC2 comprises an amino acid sequence with at least 75% sequence identity to SEQ ID NO: 26; (c) LC 1 comprises an amino acid sequence with at least 75% sequence identity’ to SEQ ID NO: 27; (d) LC2 comprises an amino acid sequence with at least 75% sequence identity to SEQ ID NO: 28; or (e) LC3 comprises an amino acid sequence with at least 75% sequence identity to SEQ ID NO: 29. In some embodiments, (a) HCl comprises an amino acid sequence with at least 75% sequence identity to SEQ ID NO: 25; (b) HC2 comprises an amino acid sequence with at least 75% sequence identity’ to SEQ ID NO: 26; (c) LC1 comprises an amino acid sequence with at least 75% sequence identity to SEQ ID NO: 27; (d) LC2 comprises an amino acid sequence with at least 75% sequence identity to SEQ ID NO: 28; and (e) LC3 comprises an amino acid sequence with at least 75% sequence identity to SEQ ID NO: 29. In some embodiments, (a) the HC 1 comprises an amino acid sequence with at least 80% sequence identity to SEQ ID NO: 25; (b) HC2 comprises an amino acid sequence with at least 80% sequence identity to SEQ ID NO: 26; (c) LC1 comprises an amino acid sequence with at least 80% sequence identity to SEQ ID NO: 27; (d) LC2 comprises an amino acidWSGR Docket No. 69143-718.601sequence with at least 80% sequence identity to SEQ ID NO: 28; or (e) LC3 comprises an amino acid sequence with at least 80% sequence identity to SEQ ID NO: 29. In some embodiments, (a) HC1 comprises an amino acid sequence with at least 80% sequence identity to SEQ ID NO: 25; (b) HC2 comprises an amino acid sequence with at least 80% sequence identity to SEQ ID NO: 26; (c) LC1 comprises an amino acid sequence with at least 80% sequence identity to SEQ ID NO: 27; (d) LC2 comprises an amino acid sequence with at least 80% sequence identity to SEQ ID NO: 28; and (e) LC3 comprises an amino acid sequence with at least 80% sequence identity to SEQ ID NO: 29. In some embodiments, (a) the HC 1 comprises an amino acid sequence with at least 85% sequence identity to SEQ ID NO: 25; (b) HC2 comprises an amino acid sequence with at least 85% sequence identity to SEQ ID NO: 26; (c) LC1 comprises an amino acid sequence with at least 85% sequence identity to SEQ ID NO: 27; (d) LC2 comprises an amino acid sequence with at least 85% sequence identity to SEQ ID NO: 28; or (e) LC3 comprises an amino acid sequence with at least 85% sequence identity’ to SEQ ID NO: 29, In some embodiments, (a) HCI comprises an amino acid sequence with at least 85% sequence identity to SEQ ID NO: 25; (b) HC2 comprises an amino acid sequence with at least 85% sequence identity to SEQ ID NO: 26; (c) LC1 comprises an amino acid sequence with at least 85% sequence identity to SEQ ID NO: 27; (d) LC2 comprises an amino acid sequence with at least 85% sequence identity to SEQ ID NO: 28; and (e) LC3 comprises an amino acid sequence with at least 85% sequence identity to SEQ ID NO: 29. In some embodiments, (a) the HCI comprises an amino acid sequence with at least 86% sequence identity to SEQ ID NO: 25; (b) HC2 comprises an amino acid sequence with at least 86% sequence identity to SEQ ID NO: 26; (c) LC1 comprises an amino acid sequence with at least 86% sequence identity to SEQ ID NO: 27; (d) LC2 comprises an amino acid sequence with at least 86% sequence identity to SEQ ID NO: 28; or (e) LC3 comprises an amino acid sequence with at least 86% sequence identity to SEQ ID NO: 29. In some embodiments, (a) HCI comprises an amino acid sequence with at least 86% sequence identity to SEQ ID NO: 25; (b) HC2 comprises an amino acid sequence with at least 86% sequence identity to SEQ ID NO: 26; (c) LC1 comprises an amino acid sequence with at least 86% sequence identity to SEQ ID NO: 27; (d) LC2 comprises an amino acid sequence with at least 86% sequence identity to SEQ ID NO: 28; and (e) LC3 comprises an amino acid sequence with at least 86% sequence identity to SEQ ID NO: 29. In some embodiments, (a) the HC 1 comprises an amino acid sequence with at least 87% sequence identity to SEQ ID NO: 25; (b) HC2 comprises an amino acid sequence with at least 87% sequence identity to SEQ ID NO: 26; (c) LC1 comprises an amino acid sequence with at least 87% sequence identity to SEQ ID NO: 27; (d) LC2 comprises an amino acid sequence with at least 87% sequence identity to SEQ ID NO: 28; or (e) LC3 comprises an amino acid sequence with at least 87% sequence identity to SEQ ID NO: 29, In some embodiments, (a) HCI comprises an amino acid sequence with at least 87% sequence identity to SEQ ID NO: 25; (b) HC2 comprises an amino acid sequence with at least 87% sequence identity to SEQ ID NO: 26; (c) LC1 comprises an amino acid sequence with at least 87% sequence identity to SEQ ID NO: 27; (d) LC2 comprises an amino acid sequence with at least 87% sequence identity to SEQ ID NO: 28; and (e) LC3 comprises an amino acid sequence with at least 87% sequence identity to SEQ ID NO: 29. In some embodiments, (a) the HCI comprises an amino acid sequence with at least 88% sequence identity to SEQWSGR Docket No. 69143-718.601ID NO: 25; (b) HC2 comprises an amino acid sequence with at least 88% sequence identity to SEQ ID NO: 26; (c) LC1 comprises an amino acid sequence with at least 88% sequence identity to SEQ ID NO: 27; (d) LC2 comprises an amino acid sequence with at least 88% sequence identity to SEQ ID NO: 28; or (e) LC3 comprises an amino acid sequence with at least 88% sequence identity’ to SEQ ID NO: 29, In some embodiments, (a) HCI comprises an amino acid sequence with at least 88% sequence identity to SEQ ID NO: 25; (b) HC2 comprises an amino acid sequence with at least 88% sequence identity to SEQ ID NO: 26; (c) LC1 comprises an amino acid sequence with at least 88% sequence identity to SEQ ID NO: 27; (d) LC2 comprises an amino acid sequence with at least 88% sequence identity to SEQ ID NO: 28; and (e) LC3 comprises an amino acid sequence with at least 88% sequence identity to SEQ ID NO: 29. In some embodiments, (a) the HCI comprises an amino acid sequence with at least 89% sequence identity to SEQ ID NO: 25; (b) HC2 comprises an amino acid sequence with at least 89% sequence identity to SEQ ID NO: 26; (c) LC1 comprises an amino acid sequence with at least 89% sequence identity to SEQ ID NO: 27; (d) LC2 comprises an amino acid sequence with at least 89% sequence identity to SEQ ID NO: 28; or (e) LC3 comprises an amino acid sequence with at least 89% sequence identity to SEQ ID NO: 29. In some embodiments, (a) HCI comprises an amino acid sequence with at least 89% sequence identity to SEQ ID NO: 25; (b) HC2 comprises an amino acid sequence with at least 89% sequence identity to SEQ ID NO: 26; (c) LC1 comprises an amino acid sequence with at least 89% sequence identity to SEQ ID NO: 27; (d) LC2 comprises an amino acid sequence with at least 89% sequence identity to SEQ ID NO: 28; and (e) LC3 comprises an amino acid sequence with at least 89% sequence identity to SEQ ID NO: 29, In some embodiments, (a) the HC1 comprises an amino acid sequence with at least 90% sequence identity to SEQ ID NO: 25; (b) HC2 comprises an amino acid sequence with at least 90% sequence identity to SEQ ID NO: 26; (c) LC1 comprises an amino acid sequence with at least 90% sequence identity to SEQ ID NO: 27; (d) LC2 comprises an amino acid sequence with at least 90% sequence identity to SEQ ID NO: 28; or (e) LC3 comprises an amino acid sequence with at least 90% sequence identity to SEQ ID NO: 29, In some embodiments, (a) HCI comprises an amino acid sequence with at least 90% sequence identity to SEQ ID NO: 25; (b) HC2 comprises an amino acid sequence with at least 90% sequence identity to SEQ ID NO: 26; (c) LC1 comprises an amino acid sequence with at least 90% sequence identity to SEQ ID NO: 27; (d) LC2 comprises an amino acid sequence with at least 90% sequence identity to SEQ ID NO: 28; and (e) LC3 comprises an amino acid sequence with at least 90% sequence identity to SEQ ID NO: 29. In some embodiments, (a) the HCI comprises an amino acid sequence with at least 91% sequence identity to SEQ ID NO: 25; (b) HC2 comprises an amino acid sequence with at least 91% sequence identity to SEQ ID NO: 26; (c) LC1 comprises an amino acid sequence with at least 91 % sequence identity to SEQ ID NO: 27; (d) LC2 comprises an amino acid sequence with at least 91% sequence identity to SEQ ID NO: 28; or (e) LC3 comprises an amino acid sequence with at least 91% sequence identity to SEQ ID NO: 29. In some embodiments, (a) HCI comprises an amino acid sequence with at least 91% sequence identity to SEQ ID NO: 25; (b) HC2 comprises an amino acid sequence with at least 91% sequence identity to SEQ ID NO: 26; (c) LC1 comprises an amino acid sequence with at least 91% sequence identity to SEQ ID NO: 27; (d) LC2 comprises an amino acid sequence with at least 91% sequence identity to SEQ ID NO:WSGR Docket No. 69143-718.60128; and (e) LC3 comprises an amino acid sequence with at least 91% sequence identity to SEQ ID NO: 29. In some embodiments, (a) the HC1 comprises an amino acid sequence with at least 92% sequence identity to SEQ ID NO: 25; (b) HC2 comprises an amino acid sequence with at least 92% sequence identity to SEQ ID NO: 26; (c) LC1 comprises an amino acid sequence with at least 92% sequence identity to SEQ ID NO: 27; (d) LC2 comprises an amino acid sequence with at least 92% sequence identity to SEQ ID NO: 28; or (e) LC3 comprises an amino acid sequence with at least 92% sequence identity to SEQ ID NO: 29. In some embodiments, (a) HC1 comprises an amino acid sequence with at least 92% sequence identity to SEQ ID NO: 25; (b) HC2 comprises an amino acid sequence with at least 92% sequence identity to SEQ ID NO: 26; (c) LC1 comprises an amino acid sequence with at least 92% sequence identity to SEQ ID NO: 27; (d) LC2 comprises an amino acid sequence with at least 92% sequence identity to SEQ ID NO: 28; and (e) LC3 comprises an amino acid sequence with at least 92% sequence identity to SEQ ID NO: 29, In some embodiments, (a) the HC1 comprises an amino acid sequence with at least 93% sequence identity to SEQ ID NO: 25; (b) HC2 comprises an amino acid sequence with at least 93% sequence identity to SEQ ID NO: 26; (c) LC1 comprises an amino acid sequence with at least 93% sequence identity to SEQ ID NO: 27; (d) LC2 comprises an amino acid sequence with at least 93% sequence identity to SEQ ID NO: 28; or (e) LC3 comprises an amino acid sequence with at least 93% sequence identity to SEQ ID NO: 29. In some embodiments, (a) HC1 comprises an amino acid sequence with at least 93% sequence identity to SEQ ID NO: 25; (b) HC2 comprises an amino acid sequence with at least 93% sequence identity to SEQ ID NO: 26; (c) LC1 comprises an amino acid sequence with at least 93% sequence identity to SEQ ID NO: 27; (d) LC2 comprises an amino acid sequence with at least 93% sequence identity to SEQ ID NO: 28; and (e) LC3 comprises an amino acid sequence with at least 93% sequence identity to SEQ ID NO: 29. In some embodiments, (a) the HC1 comprises an amino acid sequence with at least 94% sequence identity to SEQ ID NO: 25; (b) HC2 comprises an amino acid sequence with at least 94% sequence identity to SEQ ID NO: 26; (c) LC1 comprises an amino acid sequence with at least 94% sequence identity to SEQ ID NO: 27; (d) LC2 comprises an amino acid sequence with at least 94% sequence identity to SEQ ID NO: 28; or (e) LC3 comprises an amino acid sequence with at least 94% sequence identity to SEQ ID NO: 29. In some embodiments, (a) HC1 comprises an amino acid sequence with at least 94% sequence identity to SEQ ID NO: 25; (b) HC2 comprises an amino acid sequence with at least 94% sequence identity to SEQ ID NO: 26; (c) LC1 comprises an amino acid sequence with at least 94% sequence identity to SEQ ID NO: 27; (d) LC2 comprises an amino acid sequence with at least 94% sequence identity to SEQ ID NO: 28; and (e) LC3 comprises an amino acid sequence with at least 94% sequence identity to SEQ ID NO: 29. In some embodiments, (a) the HC1 comprises an amino acid sequence with at least 95% sequence identity to SEQ ID NO: 25; (b) HC2 comprises an amino acid sequence with at least 95% sequence identity to SEQ ID NO: 26; (c) LC1 comprises an amino acid sequence with at least 95% sequence identity to SEQ ID NO: 27; (d) LC2 comprises an amino acid sequence with at least 95% sequence identity to SEQ ID NO: 28; or (e) LC3 comprises an amino acid sequence with at least 95% sequence identity to SEQ ID NO: 29. In some embodiments, (a) HC1 comprises an amino acid sequence with at least 95% sequence identity to SEQ ID NO: 25; (b) HC2 comprises an amino acid sequence with at leastWSGR Docket No. 69143-718.60195% sequence identity to SEQ ID NO: 26; (c) LC1 comprises an amino acid sequence with at least 95% sequence identity to SEQ ID NO: 27; (d) LC2 comprises an amino acid sequence with at least 95% sequence identity to SEQ ID NO: 28; and (e) LC3 comprises an amino acid sequence with at least 95% sequence identity to SEQ ID NO: 29, In some embodiments, (a) the HC1 comprises an amino acid sequence with at least 96% sequence identity to SEQ ID NO: 25; (b) HC2 comprises an amino acid sequence with at least 96% sequence identity to SEQ ID NO: 26; (c) LC1 comprises an amino acid sequence with at least 96% sequence identity to SEQ ID NO: 27; (d) LC2 comprises an amino acid sequence with at least 96% sequence identity’ to SEQ ID NO: 28; or (e) LC3 comprises an amino acid sequence with at least 96% sequence identity to SEQ ID NO: 29, In some embodiments, (a) HC1 comprises an amino acid sequence with at least 96% sequence identity to SEQ ID NO: 25; (b) HC2 comprises an amino acid sequence with at least 96% sequence identity' to SEQ ID NO: 26; (c) LC1 comprises an amino acid sequence with at least 96% sequence identity to SEQ ID NO: 27; (d) LC2 comprises an amino acid sequence with at least 96% sequence identity to SEQ ID NO: 28; and (e) LC3 comprises an amino acid sequence with at least 96% sequence identity to SEQ ID NO: 29. In some embodiments, (a) the HC 1 comprises an amino acid sequence with at least 97% sequence identity' to SEQ ID NO: 25; (b) HC2 comprises an amino acid sequence with at least 97% sequence identity’ to SEQ ID NO: 26; (c) LC1 comprises an amino acid sequence with at least 97% sequence identity to SEQ ID NO: 27; (d) LC2 comprises an amino acid sequence with at least 97% sequence identity to SEQ ID NO: 28; or (e) LC3 comprises an amino acid sequence with at least 97% sequence identity to SEQ ID NO: 29. In some embodiments, (a) HC1 comprises an amino acid sequence with at least 97% sequence identity to SEQ ID NO: 25; (b) HC2 comprises an amino acid sequence with at least 97% sequence identity to SEQ ID NO: 26; (c) LC1 comprises an amino acid sequence with at least 97% sequence identity to SEQ ID NO: 27; (d) LC2 comprises an amino acid sequence with at least 97% sequence identity to SEQ ID NO: 28; and (e) LC3 comprises an amino acid sequence with at least 97% sequence identity to SEQ ID NO: 29. In some embodiments, (a) the HC1 comprises an amino acid sequence with at least 98% sequence identity to SEQ ID NO: 25; (b) HC2 comprises an amino acid sequence with at least 98% sequence identity to SEQ ID NO: 26; (c) LC1 comprises an amino acid sequence with at least 98% sequence identity to SEQ ID NO: 27; (d) LC2 comprises an amino acid sequence with at least 98% sequence identity to SEQ ID NO: 28; or (e) LC3 comprises an amino acid sequence with at least 98% sequence identity to SEQ ID NO: 29. In some embodiments, (a) HC1 comprises an amino acid sequence with at least 98% sequence identity to SEQ ID NO: 25; (b) HC2 comprises an amino acid sequence with at least 98% sequence identity’ to SEQ ID NO: 26; (c) LC I comprises an amino acid sequence with at least 98% sequence identity to SEQ ID NO: 27; (d) LC2 comprises an amino acid sequence with at least 98% sequence identity to SEQ ID NO: 28; and (e) LC3 comprises an amino acid sequence with at least 98% sequence identity to SEQ ID NO: 29. In some embodiments, (a) the HC1 comprises an amino acid sequence with at least 99% sequence identity’ to SEQ ID NO: 25; (b) HC2 comprises an amino acid sequence with at least 99% sequence identity to SEQ ID NO: 26; (c) LC 1 comprises an ammo acid sequence with at least 99% sequence identity to SEQ ID NO: 27; (d) LC2 comprises an amino acid sequence with at least 99% sequence identity to SEQ ID NO: 28; or (e) LC3 comprises an amino acidWSGR Docket No. 69143-718.601sequence with at least 99% sequence identity to SEQ ID NO: 29. In some embodiments, (a) HC1 comprises an amino acid sequence with at least 99% sequence identity to SEQ ID NO: 25; (b) HC2 comprises an amino acid sequence with at least 99% sequence identity to SEQ ID NO: 26; (c) LC1 comprises an amino acid sequence with at least 99% sequence identity to SEQ ID NO: 27; (d) LC2 comprises an amino acid sequence with at least 99% sequence identity to SEQ ID NO: 28; and (e) LC3 comprises an amino acid sequence with at least 99% sequence identity to SEQ ID NO: 29. In some embodiments, (a) HC1 comprises the amino acid sequence of SEQ ID NO: 25; (b) HC2 comprises the amino acid sequence of SEQ ID NO: 26; (c) LC1 comprises the amino acid sequence of SEQ ID NO: 27; (d) LC2 comprises the amino acid sequence of SEQ ID NO: 28; or (e) LC3 comprises the amino acid sequence of SEQ ID NO: 29. In some embodiments, (a) HC1 comprises the amino acid sequence of SEQ ID NO: 25; (b) HC2 comprises the amino acid sequence of SEQ ID NO: 26; (c) LC1 comprises the amino acid sequence of SEQ ID NO: 27; (d) LC2 comprises the amino acid sequence of SEQ ID NO: 28; and (e) LC3 comprises the amino acid sequence of SEQ ID NO: 29.|0082] In some cases, the heavy chains of the antigen-binding moieties are operably linked with each other, and the heavy chains of the antigen-binding moieties are operably linked to the Fc region. The term "‘operably linked” includes a direct linkage without any linker, and an indirect linkage using a linker such as a peptide linker. Tire peptide linker should have a length that is adequate to link two portions in such a way that they assume the correct conformation relative to one another so that they retain the desired activity.

[0083] In some cases, the linker is from about 1 to 50 amino acids in length, preferably about 1 to 30 amino acids in length. In one embodiment, linkers of 1 to 20 amino acids in length may be used, with from about 5 to about 10 amino acids finding use in some embodiments. Usefill linkers include glycine¬ serine polymers, including for example (GS)n, (GSGGS)n (SEQ ID NO: 53), (GGGGS)n (SEQ ID NO: 55), and (GGGS)n (SEQ ID NO: 54), where n is an integer of at least one (and generally from 3 to 4), glycine-alanine polymers, alanine-serine polymers, and other flexible linkers. Alternatively, a variety of nonproteinaceous polymers, including but not limited to polyethylene glycol (PEG), polypropylene glycol, polyoxyalkylenes, or copolymers of polyethylene glycol and polypropylene glycol, may find use as linkers.

[0084] In some cases, linkers can be derived from immunoglobulins and other proteins such as Ig-like proteins (e.g. TCR, FcR, KIR), hinge region-derived sequences, and other natural sequences from other proteins. Immunoglobin hinge region that links the Fab with the Fc region also belongs to a peptide linker.

[0085] Table 1 lists exemplary amino acid sequences of a multispecific antibody that binds to CD 19, CD3 and CD20 as disclosed herein.Table 1. Exemplary Antibody Amino Acid SequencesDescription of Amino Acid Sequences SEQ ID Sequences (Amino terminus to Carboxyl terminus) NO:CD 19 HCDRI DYVIH 1CD 19 HCDR2 YFNPYNDGTEYNEKFKA 2CD 19 HCDR3 GPYYYGSSPFDY 3WSGR Docket No. 69143-718.601Description of Amino Acid Sequences SEQ ID Sequences (Amino terminus to Carboxyl terminus) NO: CD 19 LCDR1 RSSQSLENSNHNTYIN 4 CD 19 LCDR2 RVSKRFS 5 CD 19 LCDR3 HQVTHVPYT 6 CD3 HCDR1 DYYIH 7 CD3 HCDR2 WISPGNVNTKYNENFKG 8 CD3 HCDR3 DGYSLYYFDY 9 CD3 LCDR1 KSSQSLLNSRTRKNYLA 10 CD3 LCDR 2 WASTRQS 11 CD3 LCDR3 TQSHTLRT 12 CD20 HCDR1 SYNMH 13 CD20 HCDR2 AIYPGNGDTSYNQKFKG 14 CD20 HCDR3 SIYYGGDWYFNV 15 CD20 LCDR1 RASSSVSYIH 16 CD20 LCDR2 ATSNLAS 17 CD20 LCDR3 QQWTSNPPT 18 CD19 VH QVQLVQSGAEVKKPGSSVKVSCKASGYTFTDYVIHWVRQA 19PGQGLEWMGYFNPYNDGTEYNEKFKARVTITADKSTSTAY MELSSLRSEDTAVYYCARGPYYYGSSPFDYWGQGTTVTV CD 19 VL DIVMTQTPLSLPVTPGEPASISCRSSQSLENSNHNTYINWYLQ 20KPGQSPQLLIYRVSKRFSGVPDRFSGSGSGTDFTLK1SRVEAE DVGVYYCHQVTHVPYTFGQGTKI EIK CD3 VH QVQLVQSGAEVKKPGSSVKVSCKASGFAFTDYYIHWVRQA 21PGQGLEWMGWISPGNVNTKYNENFKGRVTITADKSTSTAY MELSSLRSEDTAVYYCARDGYSLYYFDYWGQGTLVTV CDS VL DrVMTQSPDSLAVSLGERATINCKSSQSLLNSRTRKNYLAW 22YQQKPGQPPKLL.fYWASTRQSGVPDRFSGSGSGTDFTLTISS LQAEDVAVYYCTQSHrLRrFGGGrKVEIKCD20 VH QVQLQQPGAELVKPGASVKMSCKASGYTF'rSYNMHWVKQ 23TPGRGLEWIGAIY PGNGDTSYNQKFKGKATLTADKSSSTAY MQLSSLTSEDSAVYYCARSTYYGGDWYFNVYVGAGTTVTV SA CD20 VL QIVLSQSPAILSASPGEKVTMTCRASSSVSYIHWFQQKPGSSP 24KPWIYATSNLASGVPVRFSGSGSGTSYSLTISRVEAEDAATY YCQQWTSNPPTFGGGTKLEIKHeavy Chain 1 QVQLVQSGAEVKKPGSSVKVSCKASGYTFTDYVIHWVRQA 25 (CD19VH-Cbeta- PGQGLEWMGYFNPYNDGTEYNEKFKARVTITADKSTSTAY CD3VL-Calpha- MELSSLRSEDTAVYYCARGPYYYGSSPFDYWGQGTTVTVL hinge-Fc) EDLKNVFPPEVAVFEPSECEISHTQKATLVCLATGFYPDHVE LSWWVNGKEVHSGVCTDPQPLKEQPALQDSRYALSSRLRV SATFWQNPRNHFRCQVQFYGLSENDEWTQDRAKPVTQIVSAEAWGRGGGGSGGGGSDI VMTQSPDSLAVSLGERATINCKSWSGR Docket No. 69143-718.601Description of Amino Acid Sequences SEQ ID Sequences (Amino terminus to Carboxyl terminus) NO:SQSLLNSRTRKNYL \\VY(. X}KPGQPPKLLI\ WAS 1 RQSGVPD RFSGSGSGTDFTLTISSLQAEDVAVYYCTQSHl'LRTFGGGTK VEIKPDIQNPDPAVYQLRDSKSSDKSVCLFTDFDSQTQVSQS KDSDVYITDKCVLDMRSMDFKSNSAVAWSQKSDFACANAF QNSIIPEDTFFCSESKYGPPCPPCPAPEAAGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSQEDPEVQFNWYVDGVEVHNAKT KPREEQFNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKGLP SSIEKTISKAKGQPREPQVYTLPPCQEEMTKNQVSLWCLVK GFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSRLTV DKSRWQEGNVFSCSVMHEALHNHYTQKSLSLSLG Heavy chain 2 QVQLQQPGAELVKPGASVKMSCKASGYTFTSYNMHWVKQ 26 (CD20VH-CH1- TPGRGLEWIGAIYPGNGDTSYNQKFKGKATLTADKSSSTAY hinge-Fc) MQLSSLTSEDSAVYYCARSTYYGGDWYFNVWGAGTTVTV SAASTKGPSVFPLAPCSRSTSESTAALGCEVKDYFPEPVTVS WNSGALTSGVHTFPAVLQSSGLYSI. SSVV T VPSSSLGTKTYT CNVDHKPSN TKVDKRVESKYGPPCPPC iPAPEAAGGPSVFLF PPKPKDTLMISRTPEVTCVVVDVSQEDPEVQFNWYVDGVE WINAKTKPREEQFNSTYRVVSVLTVLHQDWLNGKEYKCK VSNKGIJ’SSIEKTISKAKGQPREPQVCTI. PPSQEEAITKNQVS LSCAVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFL VSRLTVDKSRWQEGNVFSCSVMHEALHNHYTQKSLSLSLGI. j g h f. chain 1 DIVMTQTPLSIJ’VTPGEPASISCRSSQSIJiNSNFTNTYINWYI. Q 27 (CD 19VL~C?.ipha) KPGQSPQLLIYRVSKRFSGVPDRFSGSGSGTDFTLKISRVEAE DVGVYYCHQVTHVPYTFGQGTKLEIKPDIQNPDPAVYQLRD SKSSDKSVCLFTDFDSQTQVSQSKDSDVYITDKCVLDMRSM DFKSNSAVAWSQKSDFACANAFQNSIIPEDTFFCSLight chain 2 QVQLVQSGAEVKKPGSSVKVSCKASGFAFTDWIHWVRQA 28 (CD3VH“Cbeta) PGQGLEWMGWISPGNVNTKYNENFKGRVTITADKSTSTAY MELSSLRSEDTAVYYCARDGYSLYY FDYWGQGTLVTVLED LKNVFPPEVAVFEPSECEISHTQKATLVCLATGFYPDHVELS WWVNGKEVHSGVCTDPQPLKEQPALQDSRYALSSRLRVSA TFWQNPRNHFRCQVQFYGLSENDEWTQDRAKPVTQIVSAE AWGRLight chain 3 QIVLSQSPAILSASPGEKVTMTCRASSSVSYIHWFQQKPGSSP 29 (CD20VL-CL) KPWIYATSNLASGVPVRFSGSGSGTSYSLTISRVEAEDAATY YCQQWTSNPPTFGGGTKLEIKRTVAAPSVFIFPPSDEQLKSG TASVVCLLNNFYPREAKVQWKVDNALQSGNSQESVTEQDS KDSIYSLSSTLTLSKADYEKHKVYACEVIHQGLSSPVTKSF NRGEC TCR β (Cbeta) LEDLKNVFPPEVAVFEPSECEISHTQKATLVCLATGFYPDHV 30ELSWWVNGKEVHSGVCTDPQPLKEQPALQDSRYALSSRLR VSATFWQNPRNHFRCQVQFYGLSENDEWTQDRAKPVTQIV SAEAWGR TCR a (Calpha) PDIQNPDPAVYQLRDSKSSDKSVCLFTDFDSQTQVSQSKDSD 31VYITDKCVLDMRSMDFKSNSAVAWSQKSDFACANAFQNSII PEDTFFCSHeavy Chain 1 APEAAGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSQEDPE 32 IgG4 Fc VQFNWYVDGVEVHNAKTKPREEQFNSTYRVVSVLTVLHQ (CH2-CH3) DWLNGKEYKCKVSNKGLPSSIEKTISKAKGQPREPQVYTLPwith FALA PCQEEMTKNQVSLWCLVKGFYPSDIAVEWESNGQPENNYKWSGR Docket No. 69143-718.601Description of Amino Acid Sequences SEQ ID Sequences (Amino terminus to Carboxyl terminus) NO: and knob TTPPVLDSDGSFFLYSR LTVDKSRWQEGNVFSCSVMHEALHmutation NHYTQKSLSLSLGhinge ESKYGPPCPPCP 33GS linker G GGG S GGGGS 34 Heavy Chain 2 APEAAGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSQEDPE 35 IgG4 Fc VQFNWYVDGVEVHNAKTKPREEQFNSTYRVVSVLTVLHQ(CH2-CH3) DWLNGKEYKCKVSNKGLPSSIEKTISKAKGQPREPQVCTLPPwith FA LA SQEEMTKNQVSLSCAVKGFYPSDLAVEWESNGQPENNYKTTand knob PPVLDSDGSFFLVSRLTVDKSRWQEGNVFSCSVMHEALHNHmutation YTQKSLSLSLGCH1 ASTKGPSVFPLAPCSRSTSESTAALGCLVKDYFPEPVTVSWN 36SGALTSGVHTFPAVLQSSGLYSLSSVVTVPSSSLGTKTYTCN VDHKPSNTKVDKRV CL RTVAAPSVFIFI43SDEQLKSGTASVVCLLNNFYPREAKVQW 37KVDNALQSGNSQESVTEQDSKDSTYSLSSTLTLSKADYEKH KVYACEVTHQGLSSPVTKSFNRGECCD3 -Cluster of Differentiation 3; CD 19= Cluster of Differentiation 19; CD20= Cluster of Differentiation 20; HCDR= Heavy Chain Complementarity Determining Region; LCDR= Light Chain Complementarity Determining Region; VH=Heavy Chain Variable Region; VL= Light Chain Variable Region;CL=antibody light chain constant domain; CH=antibody heavy chain constant domain; Calpha= T cell receptor alpha constant domain; Cbeta= T cell receptor beta constant domain; Fc=fragment crystallizable region; TCR a = T cell receptor alpha constant domain; TCR [3 = T cell receptor beta constant domain; CHl=heavy chain constant domain 1; CH2=heavy chain constant domain 2; CH3=heavy chain constant domain 3; IgG4= immunoglobulin G4

[0086] The antibody or antigen-binding portion thereof or the composition disclosed herein can be administered to a subject such as a human patient through various routes, including but not limited to intravenous, intradermal, transdermal, subcutaneous, intramuscular, inhalation (e.g., via aerosol), buccal (e.g., sublingual), topical (i.e., for both skin and mucosal surfaces, including airways), intrathecal, intra¬ articular, intrapleural, intracerebral, intra-arterial, intraperitoneal, oral, intralymphatic, intranasal, rectal, or vaginal administration. Other methods may include perfusion through a regional catheter or direct intralesional injection. In some cases, the antibodies or antigen-binding portion thereof or the nucleic acids disclosed herein are administered via intravenous push or infusion, delivered over a defined period.

[0087] The antibody or antigen-binding portion thereof or the composition disclosed herein can be delivered via peristaltic means or as a depot formulation, with the most appropriate delivery route depending on various factors such as the species, age, gender, and overall health of the subject, as well as the nature and severity of the condition being treated and the specific characteristics of the composition (e.g., dosage, formulation) being administered. In some cases, the route of administration is through a bolus or continuous infusion. In some cases, administration may be via subcutaneous injection at one or more sites (e.g., thigh, waist, buttocks, arm). In some cases, the compositions are administered on an outpatient basis.

[0088] In some cases, the dose of a composition containing the antibody disclosed herein is measured in milligrams per kilogram (mg / kg) of the patient's body weight. In some cases, the dose is based on theWSGR Docket No. 69143-718.601patient’s lean body weight (i.e., body weight minus body fat content). Alternatively, the dose may be expressed in milligrams per square meter (mg / m2) of the patient’s body surface area. In some cases, the dose is specified as a set amount of milligrams per dose administered to the patient.

[0089] Those skilled in the art can recognize that dosages can be tailored based on factors such as the subject’s age, sex, species, and condition (e.g., activity of an autoimmune disease or disorder), the desired level of cellular or autoimmune antibody depletion, the specific disease being treated, and / or the particular antibody or antigen-binding fragment being used. These factors can be assessed by one of ordinary skill in the art. In some cases, standard therapeutic regimens for antibody therapies, as commonly practiced in the art, may be applied in conjunction with the compositions and methods of the invention for treating a specific autoimmune disease or disorder.

[0090] The treatment regimen and dosage of the compositions described herein can be selected based on various factors, including, but not limited to, the stage of the autoimmune disease or disorder being treated. Appropriate treatment regimens can be determined by skilled practitioners for specific stages of an autoimmune disease or disorder in individual patients or patient populations.Production of Antibody

[0091] The antibody or antigen-binding fragment thereof binds to CD 19, CD20 and CD3 (the “multispecific antibody) as disclosed herein (e.g., antibodies and its binding fragments) can be produced using any method known in the art to be useful for the synthesis of polypeptides (e.g., antibodies), in particular, by chemical synthesis or by recombinant expression, and are produced by recombinant expression techniques.

[0092] A variety of recombinant methods can be used to produce multispecific antibodies and antibody fragments as described above. In general, multispecific antibodies are made by including genes for each heavy and light chain into the host cells. There are a number of mechanisms that can be used to generate the heterodimers of the present invention. In addition, these mechanisms can be combined to ensure high heterodimerization. Thus, amino acid variants that lead to the production of heterodimers are referred to as “heterodimerization variants”. As known by those in the art, heterodimerization variants can include steric variants (e.g. the “knobs and holes” or “skew” variants described below and the “charge pairs” variants) as well as “pi variants”, which allows purification of homodimers away from heterodimers. As is generally described in WO2014 / 145806, hereby incorporated by reference in its entirety and specifically as below for the discussion of “heterodimerization variants”, useful mechanisms for heterodimerization include “knobs and holes” (“KIH”; sometimes herein as “skew” variants (see discussion inWO2014 / 145806), “electrostatic steering” or “charge pairs” as described in WO2014 / 145806. DI variants as described in WO2014 / 145806, and general additional Fc variants as outlined in WO2014 / 145806. Another mechanism is the usage of engineered TCR constant regions to replace CHI and CL regions in the Fab. ’lire TCR constant regions may be engineered to incorporate one or more cysteine amino acids to form one or more non-native disulfide bonds between C and C, so that the dimer formed by the two constant regions has a better stability, expression and heterodimerization. In some instances, an antibody or its binding fragment thereof is expressed recombinantly, and the nucleic acid encoding the antibody orWSGR Docket No. 69143-718.601its binding fragment is assembled from chemically synthesized oligonucleotides (e.g., as described in Kutmeier et al., 1994, BioTechniques 17:242), which involves the synthesis of overlapping oligonucleotides containing portions of the sequence encoding the antibody, annealing and ligation of those oligonucleotides, and then amplification of the ligated oligonucleotides by PCR. Alternatively, a nucleic acid molecule encoding an antibody is optionally generated from a suitable source (e.g., an antibody cDNA library, or cDNA library generated from any tissue or cells expressing the immunoglobulin) by PCR amplification using synthetic primers hybridizable to the 3 ’ and 5 ' ends of the sequence or by cloning using an oligonucleotide probe specific for the particular gene sequence.

[0093] In some instances, an antibody or its binding is optionally generated by immunizing an animal, such as a mouse, to generate polyclonal antibodies or, more preferably, by generating monoclonal antibodies, e.g., as described by Kohler and Milstein (1975, Nature 256:495-497) or, as described by Kozbor et al. (1983, Immunology Today 4:72) or Cole et al. (1985 in Monoclonal Antibodies and Cancer Therapy, Alan R. Liss, Inc., pp. 77-96). Alternatively, a clone encoding at least the Fab portion of the antibody is optionally obtained by screening Fab expression libraries (e.g., as described in Huse et al., 1989, Science 246: 1275-1281) for clones of Fab fragments that bind the specific antigen or by screening antibody libraries (See, e.g., Clackson et al., 1991, Nature 352:624; Hane et al., 1997 Proc, Natl, Acad, Sci. USA 94:4937). In some cases, techniques developed for the production of “chimeric antibodies” (Morrison et al., 1984, Proc. Natl. Acad. Sci. 81:851-855; Neuberger et al., 1984, Nature 312:604-608; Takeda et al., 1985, Nature 314:452-454) by splicing genes from a mouse antibody molecule of appropriate antigen specificity together with genes from a human antibody molecule of appropriate biological activity are used. A chimeric antibody is a molecule in which different portions are derived from different animal species, such as those having a variable region derived from a murine monoclonal antibody and a human immunoglobulin constant region. In some cases, techniques described for the production of single chain antibodies (U. S. Pat. No. 4,694,778; Bird, 1988, Science 242:423-42; Huston et al., 1988, Proc. Natl. Acad. Sci. USA 85:5879-5883; and Ward et al., 1989, Nature 334:544-54) are adapted to produce single chain antibodies. Single chain antibodies are formed by linking the heavy and light chain fragments of the Fv region via an amino acid bridge, resulting in a single chain polypeptide. Techniques for the assembly of functional Fv fragments in E. coli are also optionally used (Skerra et al., 1988, Science 242: 1038-1041). In some cases, an expression vector comprising the nucleotide sequence of an antibody or fragmen t thereof or the nucleotide sequence of an antibody or fragment thereof is transferred to a host cell by conventional techniques (e.g., electroporation, liposomal transfection, and calcium phosphate precipitation), and the transfected cells are then cultured by conventional techniques to produce the antibody. In specific embodiments, the expression of the antibody is regulated by a constitutive, an inducible or a tissue, specific promoter. In some cases, a variety of host-expression vector systems is utilized to express an antibody, or its binding fragment described herein. Such host -expression systems represent vehicles by which the coding sequences of the antibody is produced and subsequently purified, but also represent cells that are, when transformed or transfected with the appropriate nucleotide coding sequences, express an antibody or its binding fragment in situ. These include, but are not limited to, microorganisms such as bacteria (e.g., E. coli and B. subtilis) transformed with recombinantWSGR Docket No. 69143-718.601bacteriophage DNA, plasmid DNA or cosmid DNA expression vectors containing an antibody or its binding fragment coding sequences; yeast (e.g., Saccharomyces Pichia) transformed with recombinant yeast expression vectors containing an antibody or its binding fragment coding sequences; insect cell systems infected with recombinant virus expression vectors (e.g., baculovirus) containing an antibody or its binding fragment coding sequences; plant cell systems infected with recombinant virus expression vectors (e.g., cauliflower mosaic virus (CaMV) and tobacco mosaic virus (TMV)) or transformed with recombinant plasmid expression vectors (e.g., Ti plasmid) containing an antibody or its binding fragment coding sequences; or mammalian cell systems (e.g., COS, CHO, BH, HEK293, 293T, 3T3 cells) harboring recombinant expression constructs containing promoters derived from the genome of mammalian cells (e.g., metallothionein promoter) or from mammalian viruses (e.g. the adenovirus late promoter; the vaccinia virus 7.5K promoter). For long-term, high-yield production of recombinant proteins, stable expression is preferred. In some instances, cell lines that stably express an antibody are optionally engineered. Rather than using expression vectors that contain viral origins of replication, host cells are transformed with DNA controlled by appropriate expression control elements (e.g., promoter, enhancer, sequences, transcription terminators, polyadenylation sites, etc.), and a selectable marker.Following the introduction of the foreign DNA, engineered cells are then allowed to grow for 1-2 days in an enriched media, and then are switched to a selective media. The selectable marker in the recombinant plasmid confers resistance to the selection and allows cells to stably integrate the plasmid into their chromosomes and grow to form foci that in turn are cloned and expanded into cell lines. This method can advantageously be used to engineer cell lines which express the antibody or its binding fragments.

[0094] In some instances, a number of selection systems are used, including but not limited to blasticidin, zeocin, the herpes simplex virus thymidine kinase (Wigler et al., 1977, Cell 11:223), hypoxanthine-guanine phosphoribosyltransferase (Szybalska & Szybalski, 192, Proc. Natl. Acad. Sci. USA 48:202), and adenine phosphoribosyltransferase (Lowy et al., 1980, Cell 22:817) genes are employed in tk- hgprt- or aprt- cells, respectively. Also, antimetabolite resistance are used as the basis of selection for the following genes: dhfr, which confers resistance to methotrexate (Wigler et al., 1980, Proc. Natl. Acad. Sci. USA 77:357; O'Hare et al., 1981, Proc. Natl. Acad. Sci. USA 78:1527); gpt, which confers resistance to mycophenolic acid (Mulligan & Berg, 1981, Proc. Natl. Acad. Sci. USA 78:2072); neo, which confers resistance to the aminoglycoside G-418 (Clinical Pharmacy 12:488-505; Wu and Wu, 1991, Biotherapy 3:87-95; Tolstoshev, 1993, Ann. Rev. Pharmacol. Toxicol. 32:573-596; Mulligan, 1993, Science 260:926- 932; and Morgan and Anderson, 1993, Ann. Rev. Biochem. 62: 191-217; May 1993, TIB TECH11(5): 155-215) and hygro, which confers resistance to hygromycin (Santerre et al., 1984, Gene 30: 147). Methods commonly known in the art of recombinant DN A technology which can be used are described in Ausubel et al. (eds., 1993, Current Protocols in Molecular Biology, John Wiley & Sons, NY; Kriegler, 1990, Gene Transfer and Expression, A Laboratory Manual, Stockton Press, NY; and in Chapters 12 and 13, Dracopoli et al. (eds), 1994, Current Protocols in Human Genetics, John Wiley & Sons, NY.;Colberre-Garapin et al., 1981, J. Mol. Biol. 150: 1 ). In some instances, the expression levels of a recombinant polypeptide are increased by vector amplification (for a review, see Bebbington and Hentschel, the use of vectors based on gene amplification for the expression of cloned genes inWSGR Docket No. 69143-718.601mammalian cells in DNA cloning, Vol. 3. (Academic Press, New York, 1987)). When a marker in the vector system expressing a recombinant polypeptide is amplifiable, an increase in the level of inhibitor present in culture of host cell will increase the number of copies of the marker gene. Since the amplified region is associated with the nucleotide sequence of the recombinant polypeptide, production of the recombinant polypeptide will also increase (Crouse et al., 1983, Mol. Cell Biol. 3:257). In some instances, any method known in the art for purification of a recombinant polypeptide is used, for example, by chromatography (e.g., ion exchange, affinity,, particularly by affinity for the specific antigen after Protein A, and sizing column chromatography), centrifugation, differential solubility’, or by any other standard technique for the purification of proteins.Expression Vectors

[0095] In some embodiments, vectors include any suitable vectors derived from either a eukaryotic or prokaryotic sources. In some cases, vectors are obtained from bacteria (e.g. E. coli), insects, yeast (e.g. Pichia pastoris), algae, or mammalian sources. Exemplary bacterial vectors include pA CYC 177, pASK75, pBAD vector series, pBADM vector series, pET vector series, pETM vector series, pGEX vector series, pHAT, pHAT2, pMal-c2, pMal-p2, pQE vector series, pRSET A, pRSET B, pRSET C, pTrcHis2 series, pZA31-Luc, pZE21-MCS-l, pFLAG ATS, pFLAG CTS, pFLAG MAC, pFLAG Shift-12c, pTAC-MAT-1, pFLAG CTC, or pTAC-MAT-2. Exemplary insect vectors include pFastBacl, pFastBac DUAL, pFastBac ET, pFastBac HTa, pFastBac HTb, pFastBac HTc, pFastBac M30a, pFastBact M30b, pFastBac, M30c, pVL1392, pVL1393, pVL1393 MIO, pVL1393 Ml 1, pVL1393 M12, FLAG vectors such as pPolh-FLAGl or pPolh-MAT 2, or MAT vectors such as pPolh-MATl, or pPolh-MAT2. In some cases, yeast vectors include Gateway® pDEST™ 14 vector, Gateway® pDEST™ 15 vector. Gateway® pDEST™ 17 vector, Gateway® pDEST™ 24 vector, Gateway® pYES-DEST52 vector, pBAD-DEST49 Gateway® destination vector, pAO815 Pichia vector, pFLDl Pichi pastoris vector, pGAPZA, B, & C Pichia pastoris vector, pPIC3.5K Pichia vector, pPIC6 A, B, & C Pichia vector, pPIC9K Pichia vector, pTEFl / Zeo, pYES2 yeast vector, pYES2 / CT yeast vector, pYES2 / NT A, B, & C yeast vector, or pYES3 / CT yeast vector. Exemplary algae vectors include pChlamy-4 vector or MCS vector. Examples of mammalian vectors include transient expression vectors or stable expression vectors. Mammalian transient expression vectors may include pRK5, p3xFLAG-CMV 8, pFLAG-Myc-CMV 19, pFLAG-Myc-CMV 23, pFLAG-CMV 2, pFLAG-CMV 6a,b,c, pFLAG-CMV 5.1, pFLAG-CMV 5a,b,c, p3xFLAG-CMV 7.1, pFLAG-CMV 20, p3xFLAG-Myc-CMV 24, pCMV-FLAG-MATl, pCMV-FLAG-MAT2, pBICEP-CMV 3, or pBICEP-CMV 4. Mammalian stable expression vector may include pFLAG-CMV 3, p3xFLAG-CMV 9, p3xFLAG-CMV 13, pFLAG-Myc-CMV 21, p3xFLAG-Myc-CMV 25, pFLAG-CMV 4, p3xFLAG-CMV 10, p3xFLAG-CMV 14, pFLAG-Myc-CMV 22, p3xFLAG-Myc-CMV 26, pBICEP-CMV 1, or pBICEP-CMV 2. In some instances, a cell-free system is a mixture of cytoplasmic and / or nuclear components from a cell and is used for in vitro nucleic acid synthesis. In some cases, a cell-free system utilizes either prokaryotic cell components or eukaryotic cell components. Sometimes, a nucleic acid synthesis is obtained in a cell-free system based on for example Drosophila cell, Xenopus egg, or HeLa cells. Exemplary cell-free systems include, but are not limited to, E. coli S30 Extract system, E. coli T7 S30 system, or PURExpress®.WSGR Docket No. 69143-718.601Cells

[0096] In some cases, a cell includes any suitable cell such as a naturally derived cell or a genetically modified cell. In some instances, a cell is a production cell. In some instances, a cell is a eukaryotic cell. In other instances, a cell is a prokaryotic cell. In some cases, an eukaryotic cell includes fimgi (e.g,, yeast cells), animal cell or plant cell. In some cases, a prokaryotic cell is a bacterial cell. Examples of bacterial cell include gram-positive bacteria or gram-negative bacteria. Sometimes the gram-negative bacteria is anaerobic, rod-shaped, or both. In some instances, gram-positive bacteria include Actinobacteria, Firmicutes or Tenericutes. In some cases, gram-negative bacteria include Aquificae, Deinococcus-Thermus, Fibrobacteres-Chlorobi / Bacteroidetes (FCB group), Fusobacteria, Gemmatimonadetes, Nitrospirae, Planctomycetes -Verrucomicrobia / Chlamydiae (PVC group), Proteobacteria, Spirochaetes or Synergistetes. Other bacteria can be Acidobacteria, Chloroflexi, Chrysiogenetes. Cyanobacteria, Deferribacteres, Dictyoglomi, Thermodesulfobacteria or Thermotogae. A bacterial cell can be Escherichia coli, Clostridium botulinum, or Coli bacilli. Exemplary prokaryotic cells include, but are not limited to, BL21, Maehl™, DH10B™, TOPIO, DH5a, DHIOBac™, OmniMax™, MegaX™, DH12S™, INV120, TOPIOF’, INVaF, TOPIO / P3, ccdB Survival, PIR1, PIR2, Stbl2™, Stbl3™, or Stbl4™. In some instances, animal cells include a cell from a vertebrate or from an invertebrate. In some cases, an animal cell includes a cell from a marine invertebrate, fish, insects, amphibian, reptile, or mammal. In some cases, a fungus cell includes a yeast cell, such as brewer’s yeast, baker’s yeast, or wine yeast. Fungi include ascomycetes such as yeast, mold, filamentous fungi, basidiomycetes, or zygomycetes. In some instances, yeast includes Ascomycota or Basidiomycota. In some cases, Ascomycota includes Saccharomycotina (true yeasts, e.g. Saccharomyces cerevisiae (baker’s yeast)) or Taphrinomycotina (e.g. Schizosaccharomycetes (fission yeasts)). In some cases, Basidiomycota includes Agaricomycotina (e.g. Tremellomycetes) or Pucciniomycotina (e.g. Microbotryomycetes). Exemplary yeast or filamentous fungi include, for example, the genus: Saccharomyces, Schizosaccharomyces, Candida, Pichia, Hansenula, Kluyveromyces, Zygosaccharomyces, Yarrowia, Trichosporon, Rhodosporidi, Aspergillus, Fusarium, or Trichoderma. Exemplary yeast or filamentous fungi include, for example, the species: Saccharomyces cerevisiae, Schizosaccharomyces pombe, Candida utilis, Candida boidini, Candida albicans, Candida tropicalis, Candida stellatoidea, Candida glabrata, Candida krusei, Candida parapsilosis, Candida guilliermondii, Candida viswanathii, Candida lusitaniae, Rhodotorula mucilaginosa, Pichia metanolica, Pichia angusta, Pichia pastoris, Pichia anomala, Hansenula polymorpha, Kluyveromyces lactis, Zygosaccharomyces rouxii, Yarrowia lipolytica, Trichosporon pullulans, Rhodosporidium toru-Aspergillus niger, Aspergillus nidulans, Aspergillus awamori, Aspergillus oryzae, Trichoderma reesei, Yarrowia lipolytica, Brettanomyces bruxellensis, Candida stellata, Schizosaccharomyces pombe, Torulaspora delbrueckii, Zygosaccharomyces bailii. Cryptococcus neoformans, Cryptococcus gattii, or Saccharomyces boulardii. Exemplary yeast cells include, but are not limited to, Pichia pastoris yeast strains such as GS115, KM71H, SMD1168, SMD1168H, and X-33; and Saccharomyces cerevisiae yeast strain such as INVScI.

[0097] In some instances, additional animal cells include cells obtained from a mollusk, arthropod, annelid or sponge. In some cases, an additional animal cell is a mammalian cell, e.g., from a primate, ape,WSGR Docket No. 69143-718.601equine, bovine, porcine, canine, feline or rodent. In some cases, a rodent includes mouse, rat, hamster, gerbil, hamster, chinchilla, fancy rat, or guinea pig. Exemplary mammalian cells include, but are not limited to, 293A cell line, 293FT cell line, 293F cells, 293 H cells, CHO DG44 cells, CHO-S cells, CHO-K1 cells, FUT8 KO CHOK1, ExpiCHO-S cells, Expi293F™ cells, Flp-In™ T-REx™ 293 cell line, Flp-In ™-293 cell line, Flp-In™-3T3 cell line, Flp-In™-BHK cell line, Flp-In™-CHO cell line, Flp-In™-CV-1 cell line, Flp-In™-Jurkat cell line, FreeStyle™ 293-F cells, FreeStyle™ CHO-S cells, GripTite™ 293 MSR cell line, GS-CHO cell line, HepaRG™ cells, T-REx™ Jurkat cell line, Per. C6 cells, T-RExTM-293 cell line, T-REx™-CHO cell line, and T-REx ™-HeLa cell line. In some instances, a mammalian cell is a stable cell line, or a cell line that has incorporated a genetic material of interest in to its own genome and has the capability to express the product of the genetic material after many generations of cell division. In some cases, a mammalian cell is a transient cell line, or a cell line that has not incorporated a genetic material of interest into its own genome and does not have the capability to express the product of the genetic material after many generations of cell division. In some cases, the cell is a human cell. In some cases, the human cell is a primary cell. In some cases, the cell is an ex vivo cell. Exemplary insect cells include, but are not limited to, Drosophila S2 cells, Sf9 cells, Sf21 cells, High Five ™ cells, and expresSF+® cells. In some instances, plant cells include a cell from algae. Exemplary insect cell lines include, but are not limited to, strains from Chlamydomonas reinhardtii 137c, or Synechococcus elongatus PPG 7942.Polynucleotide Encoding Multispecific Antibody

[0098] In some aspects, the disclosure is directed to an isolated nucleic acid molecule, comprising a nucleic acid sequence encoding one or more chains of the multispecific antibody or antigen-binding portion thereof.

[0099] Nucleic acids of the present disclosure can be obtained using standard molecular biology techniques. For antibodies expressed by hybridomas (e.g., hybridomas prepared from transgenic mice carrying human immunoglobulin genes as described further below), cDNAs encoding the light and heavy chains of the antibody made by the hybridoma can be obtained by standard PCR amplification or cDNA cloning techniques. For antibodies obtained from an immunoglobulin gene library (e.g., using phage display techniques), a nucleic acid encoding such antibodies can be recovered from the gene library. The isolated nucleic acid encoding the VH region can be converted to a full-length heavy chain gene by operatively linking the VH-encoding nucleic acid to another DNA molecule encoding heavy chain constant regions (CHI, CH2 and CH3, or TCR beta constant region). The sequences of human heavy chain constant region genes are known in the art (see e.g., Kabat et al. (1991), supra) and DNA fragments encompassing these regions can be obtained by standard PCR amplification. The heavy chain constant region can be an IgGl, IgG2, IgG3, IgG4, IgA, IgE, IgM or IgD constant region, but more preferably is an IgGl or IgG4 constant region. The isolated nucleic acid encoding the VL region can be converted to a full-length light chain gene (as well as a Fab light chain gene) by operatively linking the VL-encoding DNA to another DNA molecule encoding the light chain constant region, CL, or TCR alpha constant region. The sequences of human light chain constant region genes are known in the art (see e.g., Kabat etWSGR Docket No. 69143-718.601al., supra) and DNA fragments encompassing these regions can be obtained by standard PCR amplification. In some embodiments, the light chain constant region can be a kappa or lambda constant region. Once DNA fragments encoding VH and VL segments are obtained, these DNA fragments can be further manipulated by standard recombinant DNA techniques, for example to convert the variable region genes to full-length antibody chain genes, to Fab fragment genes or to a scFv gene. In these manipulations, a VL- or VH-encoding DNA fragment is operatively linked to another DNA fragment encoding another protein, such as an antibody constant region or a flexible linker, lire term ‘-operatively linked”, as used in this context, is intended to mean that the two DNA fragments are joined such that the amino acid sequences encoded by the two DNA fragments remain in-frame. In some specific embodiments, the isolated nucleic acid molecule comprises one or more nucleic acid sequence(s) selected from the group consisting of: (A) a nucleic acid sequence that encodes the heavy chain sequence of the CD19-binding moiety and the light chain sequence of the CD3-binding moiety; (B) a nucleic acid sequence that encodes the heavy chain sequence of the CD20-binding moiety; (C) a nucleic acid sequence that encodes the light chain sequence of the CD19-binding moiety; (D) a nucleic acid sequence that encodes a heavy chain sequence of the CD3-binding moiety; (E) a nucleic acid sequence that encodes the light chain sequence of the CD20-binding moiety; (F) any combinations of (A)-(E); and (G) a nucleic acid sequence that hybridized under high stringency conditions to the complementary strand of the nucleic acid sequence of (A)-(F).

[0100] In some specific embodiments, the isolated nucleic acid molecule comprises a nucleic acid sequence encoding SEQ ID NO: 25. In some specific embodiments, the isolated nucleic acid molecule comprises a nucleic acid sequence encoding SEQ ID NO: 26. In some specific embodiments, the isolated nucleic acid molecule comprises a nucleic acid sequence encoding SEQ ID NO: 27. In some specific embodiments, the isolated nucleic acid molecule comprises a nucleic acid sequence encoding SEQ ID NO: 28. In some specific embodiments, the isolated nucleic acid molecule comprises a nucleic acid sequence encoding SEQ ID NO: 29.Pharmaceutical Compositions

[0101] In some aspects, the disclosure is directed to a pharmaceutical composition comprising at least one antibody or antigen-binding portion thereof as disclosed herein and a pharmaceutically acceptable carrier. In some aspects, the present disclosure provides a pharmaceutical composition comprising a nucleic acid (DNA or RNA) encoding the antibody as disclosed herein and a pharmaceutically acceptable carrier. In some aspects, the present disclosure provides a pharmaceutical composition comprising a cell expressing the antibody as disclosed herein and a pharmaceutically acceptable carrier,

[0102] The pharmaceutical composition may optionally contain one or more additional pharmaceutically active ingredients, such as another antibody or a drug. The pharmaceutical compositions of the disclosure also can be administered in a combination therapy with, for example, another agent for autoimmune disease therapy. A pharmaceutically acceptable carrier can include, for example, a pharmaceutically acceptable liquid, gel or solid carriers, an aqueous medium, a non-aqueous medium, an anti-microbial agent, isotonic agents, buffers, antioxidants, anesthetics, suspending / dispersing agent, a chelating agent, aWSGR Docket No. 69143-718.601diluent, adjuvant, excipient or a nontoxic auxiliary substance, other known in the art various combinations of components or more. Suitable components may include, for example, antioxidants, fillers, binders, disintegrating agents, buffers, preservatives, lubricants, flavorings, thickening agents, coloring agents, emulsifiers or stabilizers such as sugars and cyclodextrin. Suitable anti-oxidants may include, for example, methionine, ascorbic acid, EDTA, sodium thiosulfate, platinum, catalase, citric acid, cysteine, mercapto glycerol, thioglycolic acid, mercapto sorbitol, butyl methyl anisole, butylated hydroxy toluene and / or propyl gallate. As disclosed in the present disclosure, in a solvent containing an antibody or an antigen-binding fragment of the present disclosure discloses compositions include one or more antioxidants such as methionine, reducing antibody or antigen binding fragment thereof may be oxidized. The oxidation reduction may prevent or reduce a decrease in binding affinity, thereby enhancing antibody stability and extended shelflife. Thus, in some embodiments, the present disclosure provides a composition comprising one or more antibodies or antigen binding fragment thereof and one or more antioxidants such as methionine. The present disclosure further provides a variety of methods, wherein an antibody or antigen binding fragment thereof is mixed with one or more anti-oxidants, such as methionine, so that the antibody or antigen binding fragment thereof can be prevented from oxidation, to extend their shelf life and / or increased acti vity. To further illustrate, pharmaceutical acceptable earners may include, for example, aqueous vehicles such as sodium chloride injection, Ringer's injection, isotonic dextrose injection, sterile water injection, or dextrose and lactated Ringer's injection, nonaqueous vehicles such as fixed oils of vegetable origin, cottonseed oil, com oil, sesame oil, or peanut oil, antimicrobial agents at bacteriostatic or fungistatic concentrations, isotonic agents such as sodium chloride or dextrose, buffers such as phosphate or citrate buffers, antioxidants such as sodium bisulfate, local anesthetics such as procaine hydrochloride, suspending and dispersing agents such as sodium carboxymethylcelluose, hydroxypropyl methylcellulose, or polyvinylpyrrolidone, emulsifying agents such as Polysorbate 80 (TWEEN-80), sequestering or chelating agents such as ED TA (ethylenediaminetetraacetic acid) or EGTA (ethylene glycol tetraacetic acid), ethyl alcohol, polyethylene glycol, propylene glycol, sodium hydroxide, hydrochloric acid, citric acid, or lactic acid. Antimicrobial agents utilized as carriers may be added to pharmaceutical compositions in multiple-dose containers that include phenols or cresols, mercurials, benzyl alcohol, chlorobutanol, methyl and propyl p-hydroxybenzoic acid esters, thimerosal, benzalkonium chloride and benzethonium chloride. Suitable excipients may include, for example, water, saline, dextrose, glycerol, or ethanol. Suitable non-toxic auxiliary substances may include, for example, wetting or emulsifying agents, pH buffering agents, stabilizers, solubility enhancers, or agents such as sodium acetate, sorbitan monolaurate, triethanolamine oleate, or cyclodextrin.

[0103] The pharmaceutical composition of the disclosure may be administered in vivo, to a subject in need thereof, by various routes, including, but not limited to, oral, intravenous, intra-arterial, subcutaneous, parenteral, intranasal, intramuscular, intracranial, intracardiac, intraventricular, intratracheal, buccal, rectal, intraperitoneal, intradermal, topical, transdermal, and intrathecal, or otherwise by implantation or inhalation, The subject compositions may be formulated into preparations in solid, semi-solid, liquid, or gaseous forms; including, but not limited to, tablets, capsules, powders, granules, ointments, solutions, suppositories, enemas, injections, inhalants, and aerosols. The appropriateWSGR Docket No. 69143-718.601formulation and route of administration may be selected according to the intended application and therapeutic regimen. Suitable formulations for enteral administration include hard or soft gelatin capsules, pills, tablets, including coated tablets, elixirs, suspensions, syrups or inhalations and controlled release forms thereof. Formulations suitable for parenteral administration (e.g., by injection), include aqueous or non-aqueous, isotonic, pyrogen-free, sterile liquids (e.g., solutions, suspensions), in which the active ingredient is dissolved, suspended, or otherwise provided (e.g., in a liposome or other microparticulate). Such liquids may additional contain other pharmaceutically acceptable ingredients, such as anti-oxidants, buffers, preservatives, stabilizers, bacteriostats, suspending agents, thickening agents, and solutes which render the formulation isotonic with the blood (or other relevant bodily fluid) of the intended recipient. Examples of excipients include, for example, water, alcohols, polyols, glycerol, vegetable oils, and the like. Examples of suitable isotonic carriers for use in such formulations include Sodium Chloride Injection, Ringer's Solution, or Lactated Ringer's Injection, Similarly, the particular dosage regimen, including dose, timing and repetition, will depend on the particular individual and that individual's medical history, as well as empirical considerations such as pharmacokinetics (e.g., half-life, clearance rate, etc.). Frequency of administration may be determined and adjusted over the course of therapy, and is based on reducing the number of immune cells, for example, B cells, more specifically, pathological B cells, maintaining the reduction of such B cells, reducing the proliferation of B cells, or delaying the development of autoimmunity. In some embodiments, the dosage administered may be adjusted or attenuated to manage potential side effects and / or toxicity. Alternatively, sustained continuous release formulations of a subject therapeutic composition may be appropriate. It will be appreciated by one of skill in the art that appropriate dosages can vary from patient to patient. Determining the optimal dosage will generally involve the balancing of the level of therapeutic benefit against any risk or deleterious side effects. The selected dosage level will depend on a variety of factors including, but not limited to, the activity of the particular compound, the route of administration, the time of administration, the rate of excretion of the compound, the duration of the treatment, other drugs, compounds, and / or materials used in combination, the severity of the condition, and the species, sex, age, weight, condition, general health, and prior medical history of the patient. The amount of compound and route of administration will ultimately be at the discretion of the physician, veterinarian, or clinician, although generally the dosage will be selected to achieve local concentrations at the site of action that achieve the desired effect without causing substantial harmful or deleterious side-effects. In any event, the antibody or the antigen binding portion thereof of the disclosure is administered as needed to subjects in need thereof. Determination of the frequency of administration may be made by persons skilled in the art, such as an attending physician based on considerations of the condition being treated, age of the subject being treated, severity of the condition being treated, general state of health of the subject being treated and the like.Pharmaceutical packs and kits

[0104] Pharmaceutical packs and kits comprising one or more containers, comprising one or more doses of the antibody or the antigen-binding portion thereof are also provided. In certain embodiments, a unit dosage is provided wherein the unit dosage contains a predetermined amount of a compositionWSGR Docket No. 69143-718.601comprising, for example, the antibody or the antigen -binding portion thereof, with or without one or more additional agents. For other embodiments, such a unit dosage is supplied in single-use prefilled syringe for injection. The present disclosure also provides kits for producing single-dose or multi-dose administration units of antibodies and, optionally, one or more agents for autoimmune therapy. The kit comprises a container and a label or package insert on or associated with the container. Suitable containers include, for example, bottles, vials, syringes, etc. The containers may be formed from a variety of materials such as glass or plastic and contain a pharmaceutically effective amount of the disclosed antibodies in a conjugated or unconjugated form. In other preferred embodiments, the container(s) comprise a sterile access port (for example the container may be an intravenous solution bag or a vial having a stopper pierceable by a hypodermic injection needle). Such kits will generally contain in a suitable container a pharmaceutically acceptable formulation of the antibodies and, optionally, one or more agents for autoimmune therapy in the same or different containers. The kits may also contain other pharmaceutically acceptable formulations, either for diagnosis or combined therapy. For example, in addition to the antibody or the antigen -binding portion thereof of the disclosure such kits may contain any one or more of a range of agents for autoimmune therapy. When the components of the kit are provided in one or more liquid solutions, the liquid solution is preferably an aqueous solution, with a sterile aqueous or saline solution being particularly preferred. However, the components of the kit may be provided as dried powder(s). When reagents or components are provided as a dry powder, the powder can be reconstituted by the addition of a suitable solvent. It is envisioned that the solvent may also be provided in another container. As indicated briefly above the kits may also contain a means by which to administer the antibody or the antigen-binding portion thereof and any optional components to a patient, e.g., one or more needles, I. V. bags or syringes, or even an eye dropper, pipette, or other such like apparatus, from which the formulation may be injected or introduced into the animal or applied to a diseased area of the body. The kits of the present disclosure will also typically include a means for containing the vials, or such like, and other component in close confinement for commercial sale, such as, e.g., injection or blow- molded plastic containers into which the desired vials and other apparatus are placed and retained.NUMBERED EMBODIMENTS

[0105] Embodiment 1 A method for treating an autoimmune disease or disorder in a subject, comprising administering to the subject a therapeutically effective amount of (i) an antibody or antigenbinding portion thereof comprising a CD 19 binding moiety, a CD3 binding moiety and a CD20 binding moiety, or (ii) one or more polynucleotide encoding the antibody or antigen-binding portion thereof; wherein:(a) the CDI9 binding moiety comprises a heavy chain complementarity determining region (HCDR) 1, a HCDR2 and a HCDR3 comprising the amino acid sequences of SEQ ID NOs: 1, 2 and 3, respectively, and a light chain complementarity determining region (LCDR) 1, a LCDR2 and a LCDR3 comprising the amino acid sequences of SEQ ID NOs: 4, 5 and 6, respectively;(b) the CD3 binding moiety comprises a HCDR1, a HCDR2 and a HCDR3 comprising the amino acid sequences of SEQ ID NOs: 7, 8 and 9, respectively, and a LCDR1, a LCDR2 and aWSGR Docket No. 69143-718.601LCDR3 comprising the amino acid sequences of SEQ ID NOs: 10, 11 and 12, respectively; and(c) the CD20 binding moiety comprises a HCDR1, a HCDR2 and a HCDR3 comprising the amino acid sequences of SEQ ID NOs: 13, 14 and 15, respectively, and a LCDR1, a LCDR2 and a LCDR3 comprising the amino acid sequences of SEQ ID NOs: 16, 17 and 18, respectively.

[0106] Embodiment 2 The method of embodiment 1, wherein the autoimmune disease or disorder comprises an autoantibody-driven disease.

[0107] Embodiment 3 The method of embodiment 1 or 2, wherein the autoimmune disease or disorder comprises a disease mediated by an autoantibody.

[0108] Embodiment 4 The method of any one of embodiments 1-3, wherein the autoimmune disease or disorder comprises a disease mediated by a B cell, a plasmablast, or a plasma cell,

[0109] Embodiment 5 The method of any one of embodiments 1-4, wherein the autoimmune disease or disorder comprises a disease mediated by a mature B cell, a memory B cell, or an activated B cell.

[0110] Embodiment 6 The method of any one of embodiments 1-5, wherein the autoimmune disease or disorder comprises allergy, antibody-mediated rejection, alloantibodies, a disease related to or mediated by an alloantibody, amyloidosis, anti-glomerular basement membrane (GBM) (Goodpasture Syndrome), anti-N-methyl-D-aspartate receptor (NMDA) encephalitis (anti-NMDA-R Encephalitis), anti-neutrophil cytoplasmic autoantibody-associated vasculitis (ANCA vasculitis), antiphospholipid antibody syndrome, antisynthetase Syndrome, atopic dermatitis, autoimmune hepatitis, autoimmune necrotizing myopathy, Behcet’s disease. Bullous Pemphigoid, Celiac disease, Chronic Inflammatory Demyelinating Polyneuropathy (GDP), Crohn’s disease, dilated cardiomyopathy, Graves, Guillain Barre Syndrome, Hidradenitis Suppurativa, IgA Nephropathy, Immunoglobulin G4-related disease (lgG4-RD), immune vasculitis (IgA), immune thrombocytopenia (IIP), Long COVID, Lupus Nephritis, Membranous Nephropathy, microscopic polyangiitis, multiple sclerosis (MS) - primary progressive multiple sclerosis (MS-PPMS), multiple sclerosis (MS) -relapsing-remitting multiple sclerosis (MS-RRMS), Myasthenia Gravis, myositis-dermatomyositis, myositis-inclusion body, myositis-polymyositis, myositis- immune-mediated necrotizing myositis, neuromyelitis optica spectrum disorder (NMOSD), Pemphigus Vulgaris, polyneuropathy, organomegaly, endocrinopathy, M-protein and skin changes (POEMS) syndrome.Postural Orthostatic Tachycardia Syndrome (POTS), Polyarteritis Nodosa, Primary Biliary Cirrhosis, Primary Sclerosing Cholangitis, Psoriasis, Psoriatic Arthritis, Raynaud’s Syndrome, Reactive Arthritis, rheumatoid arthritis, scleroderma or systemic sclerosis, Sjogren's Syndrome, Stiff Person Syndrome, Type 1 diabetes, Thyroid eye disease, tumor progression, or ulcerative colitis.

[0111] Embodiment 7 The method of any one of embodiments 1-6, wherein the autoimmune disease or disorder comprises allergy.

[0112] Embodiment 8 The method of any one of embodiments 1-6, wherein the autoimmune disease or disorder comprises antibody-mediated rejection.

[0113] Embodiment 9 The method of any one of embodiments 1-6, wherein the autoimmune disease or disorder comprises alloantibodies.WSGR Docket No. 69143-718.601

[0114] Embodiment 10 The method of any one of embodiments 1 -6, wherein the autoimmune disease or disorder comprises a disease related to or mediated by an alloantibody.

[0115] Embodiment 11 The method of any one of embodiments 1-6, wherein the autoimmune disease or disorder comprises amyloidosis.

[0116] Embodiment 12 The method of any one of embodiments 1-6, wherein the autoimmune disease or disorder comprises anti-GBM (Goodpasture Syndrome).

[0117] Embodiment 13 The method of any one of embodiments 1-6, wherein the autoimmune disease or disorder comprises anti-NMDA-R Encephalitis.

[0118] Embodiment 14 The method of any one of embodiments 1 -6, wherein the autoimmune disease or disorder comprises ANCA vasculitis.

[0119] Embodiment 15 The method of any one of embodiments 1-6, wherein the autoimmune disease or disorder comprises antiphospholipid antibody syndrome,

[0120] Embodiment 16 The method of any one of embodiments 1-6, wherein the autoimmune disease or disorder comprises antisynthetase Syndrome.

[0121] Embodiment 17 The method of any one of embodiments 1-6, wherein the autoimmune disease or disorder comprises atopic dermatitis.

[0122] Embodiment 18 The method of any one of embodiments 1-6, wherein the autoimmune disease or disorder comprises autoimmune hepatitis.

[0123] Embodiment 19 The method of any one of embodiments 1-6, wherein the autoimmune disease or disorder comprises autoimmune necrotizing myopathy.

[0124] Embodiment 20 The method of any one of embodiments 1-6, wherein the autoimmune disease or disorder comprises Behcet’s disease.

[0125] Embodiment 21 The method of any one of embodiments 1-6, wherein the autoimmune disease or disorder comprises Bullous Pemphigoid.

[0126] Embodiment 22 The method of any one of embodiments 1-6, wherein the autoimmune disease or disorder comprises Celiac disease.

[0127] Embodiment 23 The method of any one of embodiments 1-6, wherein the autoimmune disease or disorder comprises CIDP.

[0128] Embodiment 24 The method of any one of embodiments 1-6, wherein the autoimmune disease or disorder comprises Crohn’s disease.

[0129] Embodiment 25 The method of any one of embodiments 1-6, wherein the autoimmune disease or disorder comprises dilated cardiomyopathy.

[0130] Embodiment 26 The method of any one of embodiments 1 -6, wherein the autoimmune disease or disorder comprises Graves.

[0131] Embodiment 27 The method of any one of embodiments 1-6, wherein the autoimmune disease or disorder comprises Guillain Barre Syndrome.

[0132] Embodiment 28 The method of any one of embodiments 1-6, wherein the autoimmune disease or disorder comprises Hidradenitis Suppurativa.WSGR Docket No. 69143-718.601

[0133] Embodiment 29 The method of any one of embodiments 1 -6, wherein the autoimmune disease or disorder comprises IgA Nephropathy.

[0134] Embodiment 30 The method of any one of embodiments 1-6, wherein the autoimmune disease or disorder comprises IgG4-RD

[0135] Embodiment 31 The method of any one of embodiments 1-6, wherein the autoimmune disease or disorder comprises immune vasculitis (IgA).

[0136] Embodiment 32 The method of any one of embodiments 1-6, wherein the autoimmune disease or disorder comprises ITP.

[0137] Embodiment 33 The method of any one of embodiments 1 -6, wherein the autoimmune disease or disorder comprises Long COVID.

[0138] Embodiment 34 The method of any one of embodiments 1-6, wherein the autoimmune disease or disorder comprises Lupus Nephritis.

[0139] Embodiment 35 The method of any one of embodiments 1-6, wherein the autoimmune disease or disorder comprises Membranous Nephropathy.

[0140] Embodiment 36 The method of any one of embodiments 1-6, wherein the autoimmune disease or disorder comprises microscopic polyangiitis,

[0141] Embodiment 37 The method of any one of embodiments 1 -6, wherein the autoimmune disease or disorder comprises MS-PPMS.

[0142] Embodiment 38 The method of any one of embodiments 1-6, wherein the autoimmune disease or disorder comprises MS-RRMS.

[0143] Embodiment 39 The method of any one of embodiments 1-6, wherein the autoimmune disease or disorder comprises Myasthenia Gravis.

[0144] Embodiment 40 The method of any one of embodiments 1-6, wherein the autoimmune disease or disorder comprises myositis-dermatomyositis.

[0145] Embodiment 41 The method of any one of embodiments 1 -6, wherein the autoimmune disease or disorder comprises myositis-inclusion body.

[0146] Embodiment 42 The method of any one of embodiments 1-6, wherein the autoimmune disease or disorder comprises myositis-polymyositis.

[0147] Embodiment 43 The method of any one of preceding embodiments, wherein the autoimmune disease or disorder comprises myositis-immune-mediated necrotizing myositis.

[0148] Embodiment 44 The method of any one of embodiments 1-6, wherein the autoimmune disease or disorder comprises NMOSD.

[0149] Embodiment 45 The method of any one of embodiments 1 -6, wherein the autoimmune disease or disorder comprises Pemphigus Vulgaris.

[0150] Embodiment 46 The method of any one of embodiments 1-6, wherein the autoimmune disease or disorder comprises POEMS syndrome.

[0151] Embodiment 47 The method of any one of embodiments 1-6, wherein the autoimmune disease or disorder comprises POTS.WSGR Docket No. 69143-718.601

[0152] Embodiment 48 The method of any one of embodiments 1 -6, wherein the autoimmune disease or disorder comprises Polyarteritis Nodosa.

[0153] Embodiment 49 The method of any one of embodiments 1-6, wherein the autoimmune disease or disorder comprises Primary Biliary’ Cirrhosis.

[0154] Embodiment 50 The method of any one of embodiments 1-6, wherein the autoimmune disease or disorder comprises Primary Sclerosing Cholangitis.

[0155] Embodiment 51 The method of any one of embodiments 1-6, wherein the autoimmune disease or disorder comprises Psoriasis,

[0156] Embodiment 52 The method of any one of embodiments 1 -6, wherein the autoimmune disease or disorder comprises Psoriatic Arthritis.

[0157] Embodiment 53 The method of any one of embodiments 1-6, wherein the autoimmune disease or disorder comprises Raynaud’s Syndrome.

[0158] Embodiment 54 The method of any one of embodiments 1-6, wherein the autoimmune disease or disorder comprises Reactive Arthritis.

[0159] Embodiment 55 The method of any one of embodiments 1-6, wherein the autoimmune disease or disorder comprises rheumatoid arthritis

[0160] Embodiment 56 The method of any one of embodiments 1 -6, wherein the autoimmune disease or disorder comprises scleroderma or systemic sclerosis.

[0161] Embodiment 57 The method of any one of embodiments 1-6, wherein the autoimmune disease or disorder comprises Sjogren’s Syndrome,

[0162] Embodiment 58 The method of any one of embodiments 1-6, wherein the autoimmune disease or disorder comprises Stiff Person Syndrome.

[0163] Embodiment 59 The method of any one of embodiments 1-6, wherein the autoimmune disease or disorder comprises Type 1 diabetes.

[0164] Embodiment 60 The method of any one of embodiments 1 -6, wherein the autoimmune disease or disorder comprises Thyroid eye disease.

[0165] Embodiment 61 The method of any one of embodiments 1-6, wherein the autoimmune disease or disorder comprises tumor progression.

[0166] Embodiment 62 The method of any one of embodiments 1-6, wherein the autoimmune disease or disorder comprises ulcerative colitis.

[0167] Embodiment 63 The method of any one of embodiments 1-62, wherein the subject is a human or non -human primate.

[0168] Embodiment 64 The method of any one of embodiments 1 -63, wherein the subject is a human and is diagnosed with the autoimmune disease or disorder or suspected to have the autoimmune disease or disorder.

[0169] Embodiment 65 The method of any one of embodiments 1-64, wherein the therapeutically effective amount of the antibody or antigen-binding portion thereof is calculated based on a biomarker,

[0170] Embodiment 66 The method of any one of embodiments 1-65, wherein the method further comprises measuring a biomarker in the subject.WSGR Docket No. 69143-718.601

[0171] Embodiment 67 The method of embodiment 65 or 66, wherein the biomarker comprises a B cell, a plasmablast, a plasma cell, an autoantibody, or an immunoglobulin (Ig).

[0172] Embodiment 68 The method of any one of embodiments 65-67, wherein the biomarker comprises a mature B cell, a memory B cell, or an activated B cell.

[0173] Embodiment 69 The method of any one of embodiments 65-68, wherein the biomarker comprises a free kappa light chain or a free lambda light chain.

[0174] Embodiment 70 The method of any one of embodiments 67-69, wherein the immunoglobulin comprises IgD, IgG, IgA, or IgM.

[0175] Embodiment 71 The method of any one of embodiments 65-70, wherein the therapeutically effective amount is calculated based on an amount of the biomarker.

[0176] Embodiment 72 The method of any one of embodiments 65-71, wherein the therapeutically effective amount is calculated based on an amount of the biomarker in tonsil, mucosal lamina propria (LP), blood, spleen, lymph node, or bone marrow, and optionally the lymph node is mesenteric lymph node.

[0177] Embodiment 73 The method of any one of embodiments 65-72, wherein the therapeutically effective amount is calculated based on a reduction in the amount of the biomarker in the tonsil, mucosal LP, blood, spleen, lymph node, or bone marrow, after the administering, and optionally the lymph node is mesenteric lymph node.

[0178] Embodiment 74 The method of any one of embodiments 1-73, wherein the antibody or antigenbinding portion thereof is administered subcutaneously, intramuscularly or intravenously.

[0179] Embodiment 75 The method of any one of embodiments 1-74, wherein the administering results in elimination or reduction of a B cell, a plasmablast, or a plasma cell.

[0180] Embodiment 76 The method of any one of embodiments 1-75, wherein the administering results in elimination or reduction of a mature B cell, a memory B cell, or an activated B cell.

[0181] Embodiment 77 The method of any one of embodiments 1-76, wherein the administering results in elimination or reduction of an autoantibody.

[0182] Embodiment 78 The method of any one of embodiments 1-77, wherein the administering results in elimination or reduction of the B cell, the plasmablast, or the plasma cell through antibodydependent cellular cytotoxicity (ADCC), antibody-dependent cellular phagocytosis (ADCP), and / or complement-dependent cytotoxicity (CDC).

[0183] Embodiment 79 The method of any one of embodiments 1-78, wherein the administering results in elimination or reduction of the B cell, the plasmablast, or the plasma cell and the B cell, the plasmablast, or the plasma cell expresses CD19.

[0184] Embodiment 80 The method of any one of embodiments 1-79, wherein the administering results in elimination or reduction of the B cell, the plasmablast, or the plasma cell and the B cell, the plasmablast, or the plasma cell expresses CD20.

[0185] Embodiment 81 The method of any one of embodiments 1-80, wherein the administering results in elimination or reduction of the B cell, the plasmablast, or the plasma cell and the B cell, the plasmablast, or the plasma cell expresses CD 19 and CD20, or CD 138.WSGR Docket No. 69143-718.601

[0186] Embodiment 82 The method of any one of embodiments 79-81, wherein the B cell, the plasmablast, or the plasma cell is in tonsil, mucosal lamina propria (LP), blood, spleen, lymph node, or bone marrow.

[0187] Embodiment 83 The method of embodiment 82, wherein the lymph node is mesenteric lymph node.

[0188] Embodiment 84 The method of any one of embodiments 1-83, wherein the administering results in an increase of a concentration of a cytokine and optionally the cytokine is in the serum.

[0189] Embodiment 85 The method of embodiment 84, wherein the cytokine comprises interleukin 2 (IL-2), IL-6, interferon gamma (IFN-y), tumor necrosis factor alpha (TNF-a), or any combination thereof.

[0190] Embodiment 86 The method of embodiment 84 or 85, wherein the increase of the concentration of the cytokine is transient or the concentration of the cytokine returns to a level similar to or same as a level before the administering after the increase.

[0191] Embodiment 87 The method of any one of embodiments 1-86, wherein the administering results in elimination or reduction of T cells.

[0192] Embodiment 88 The method of embodiment 87, wherein the elimination or reduction of T cells is transient, or the number of T cells returns a level similar to, same as, or higher than, a level before the administering after the elimination or reduction.

[0193] Embodiment 89 The method of embodiment 87 or 88, wherein the T cells are early activated T cells, late activated T cells, or proliferating T cells.

[0194] Embodiment 90 Tire method of any one of embodiments 87-89, wherein the T cells express CD69, CD25, Ki-67, or any combination thereof.

[0195] Embodiment 91 The method of any one of embodiments 87-90, wherein the administering results in an increase in the expression of CD25, CD69, or both, in T cells.

[0196] Embodiment 92 The method of embodiment 91, wherein the T cells comprise CD4-positive T cells, CD8-positive T cells, or both.

[0197] Embodiment 93 The method of any one of embodiments 87-92, wherein the T cells are from tonsil, mucosal lamina propria (LP), blood, spleen, lymph node, or bone marrow, and optionally the lymph node is mesenteric lymph node.

[0198] Embodiment 94 The method of any one of embodiments 1 -63 and 65-93, wherein the subject is a monkey.

[0199] Embodiment 95 The method of embodiment 94, wherein the subject is a cynomolgus monkey.

[0200] Embodiment 96 The method of embodiment 95, further comprising administering a single dose or multiple doses of the antibody or antigen-binding fragment thereof,

[0201] Embodiment 97 The method of embodiment 96, further comprising administering the antibody or antigen -binding fragment thereof on a weekly basis.

[0202] Embodiment 98 The method of any one of embodiments 94-97, further comprising administering a single dose of 0.5 mg / kg, 1.5 mg / kg, 5 mg / kg, or 15 mg / kg of the antibody or antigenbinding fragment thereof on day 1 and the dose is calculated based on the weigh t of the subject.WSGR Docket No. 69143-718.601

[0203] Embodiment 99 The method of any one of embodiments 94-96, further comprising administering a first dose and a second dose of the antibody or antigen-binding fragment thereof, wherein the first dose is administered on day 1 and the second dose is administered on day 8.

[0204] Embodiment 100 The method of embodiment 99, wherein the first dose and second dose are both 15 mg / kg and the dose is calculated based on the weight of the subject.

[0205] Embodiment 101 The method of embodiment 99, wherein the first dose and second dose are 15 mg / kg and 100 mg / kg, respectively, and the dose is calculated based on the weight of the subject.

[0206] Embodiment 102 The method of any one of embodiments 98-101, wherein the administering results in a transient increase of IL-6 and INF-y levels in the serum within 8 hours after the administering on day 1.

[0207] Embodiment 103 The method of embodiment 102, wherein the IL-6 and INF-y levels in the serum are similar to or the same as the levels before the administering within 24 to 48 hours after the administering on day 1.

[0208] Embodiment 104 The method of any one of embodiments 98-103, wherein the administering results in elimination or reduction of B cells in the blood within 4 hours or 2.4 hours after the administering.

[0209] Embodiment 105 The method of any one of embodiments 98-104, wherein the administering results in elimination of B cells in the blood within 3 or 7 days after the administering.

[0210] Embodiment 106 The method of any one of embodiments 99-105, wherein the administering results in elimination of B cells in the blood that lasts at least until day 15 after the administering the second dose.

[0211] Embodiment 107 The method of any one of embodiments 98-106, wherein the administering results in elimination or reduction of T cells in the blood within 4 or 24 hours after the administering, wherein after the elimination or reduction, the number of T cells increases to a level that is higher than a level before tire administering by day 8.

[0212] Embodiment 108 The method of embodiment 107, wherein the administering results in an increase of T cells in the blood within 4 hours or 24 hours after the administering, wherein the T cells express CD69, CD25, Ki-67, or any combination thereof, wherein after the increase, the number of T cells is higher than the amount before the administering by day 8.

[0213] Embodiment 109 The method of any one of embodiments 99-108, wherein the number of T cells in the blood is the same as or higher than the number of T cells before the administering by day 15 after the administering the second dose.

[0214] Embodiment 110 The method of any one of embodiments 94-109, wherein the administering results in elimination or reduction of B cells in the bone marrow, spleen, or mesenteric lymph node and the percentage of elimination or reduction of B cells increases when the dose becomes higher.

[0215] Embodiment 111 The method of any one of embodiments 94-110, wherein the administering results in elimination or reduction of B cells in the bone marrow, spleen, and mesenteric lymph node and the percentage of elimination or reduction of B cells increases when the dose becomes higher.WSGR Docket No. 69143-718.601

[0216] Embodiment 112 The method of embodiment 111, wherein the administering results in elimination of B cells in the bone marrow, spleen, and mesenteric lymph node at 5 mg / kg or higher doses.

[0217] Embodiment 113 The method of any one of embodiments 104-112, wherein the B cells express CD 19, CD20, CD 138, or any combination thereof,

[0218] Embodiment 114 The method of any one of embodiments 104-113, wherein the reduction of B cells is about 0-100%.

[0219] Embodiment 115 The method of any one of embodiments 1-114, further comprising revaccinating the subject.

[0220] Embodiment 116 The method of any one of embodiments 1-115, further comprising administering to the subject a pharmaceutical composition comprising the antibody or antigen-binding fragment thereof or the one or more polynucleotide encoding the antibody or antigen-binding portion thereof, and a pharmaceutically acceptable carrier or excipient.

[0221] Embodiment 117 The method of any one of embodiments 1-116, wherein:(a) the CD 19 binding moiety comprises a heavy chain variable region (CD19VH) and a light chain variable region (CD19VL);(b) the CD3 binding moiety comprises a heavy chain variable region (CD3VH) and a light chain variable region (CD3VL); and(c) the CD20 binding moiety comprises a heavy chain variable region (CD20VH) and a light chain variable region (CD20VL).

[0222] Embodiment 118 Tire method of any one of embodiments 1-117, wherein the antibody or antigen -binding portion thereof further comprises a first binding arm and a second binding arm, wherein the first binding arm comprises the CD 19 binding moiety and the CD3 binding moiety and the second binding arm comprises the CD20 binding moiety.

[0223] Embodiment 119 The method of embodiment 117 or 118, wherein:(a) the CD19VH comprises an amino acid sequence with at least 90% sequence identity to SEQ ID NO: 19;(b) the CD19VL comprises an amino acid sequence with at least 90% sequence identity to SEQ ID NO: 20;(c) the CD3VH comprises an amino acid sequence with at least 90% sequence identity to SEQ ID NO: 21;(d) the CD3VL comprises an amino acid sequence with at least 90% sequence identity to SEQ ID NO: 22;(e) the CD20VH comprises an amino acid sequence with at least 90% sequence identity to SEQ ID NO: 23; or(f) the CD20VL comprises an amino acid sequence with at least 90% sequence identity to SEQ ID NO: 24.

[0224] Embodiment 120 The method of any one of embodiments 117-119, wherein:(a) the CD19VH comprises an amino acid sequence with at least 90% sequence identity to SEQ ID NO: 19;WSGR Docket No. 69143-718.601(b) the CD19VL comprises an amino acid sequence with at least 90% sequence identity to SEQ ID NO: 20;(c) the CD3VH comprises an amino acid sequence with at least 90% sequence identity to SEQ ID NO: 21;(d) the CD3VL comprises an amino acid sequence with at least 90% sequence identity to SEQ ID NO: 22;(e) the CD20VH comprises an amino acid sequence with at least 90% sequence identity to SEQ ID NO: 23; and(f) the CD20VL comprises an amino acid sequence with at least 90% sequence identity to SEQ ID NO: 24.

[0225] Embodiment 121 The method of any one of embodiments 117-120, wherein:(a) the CD19VH comprises an amino acid sequence with at least 95% sequence identity to SEQ ID NO: 19;(b) the CD19VL comprises an amino acid sequence with at least 95% sequence identity to SEQ ID NO: 20;(c) the CD3VH comprises an amino acid sequence with at least 95% sequence identity to SEQ ID NO: 21;(d) the CD3VL comprises an amino acid sequence with at least 95% sequence identity to SEQ ID NO: 22;(e) the CD20VH comprises an amino acid sequence with at least 95% sequence identity to SEQ ID NO: 23; or(f) the CD20VL comprises an amino acid sequence with at least 95% sequence identity to SEQ ID NO: 24.

[0226] Embodiment 122 The method of any one of embodiments 117-121, wherein:(a) the CD19VH comprises an amino acid sequence with at least 95% sequence identity to SEQ ID NO: 19;(b) the CD19VL comprises an amino acid sequence with at least 95% sequence identity to SEQ ID NO: 20;(c) the CD3VH comprises an amino acid sequence with at least 95% sequence identity to SEQ ID NO: 21;(d) the CD3VL comprises an amino acid sequence with at least 95 % sequence identity to SEQ ID NO: 22;(e) the CD20VH comprises an amino acid sequence with at least 95% sequence identity to SEQ ID NO: 23; and(f) the CD20VL comprises an amino acid sequence with at least 95% sequence identity to SEQ ID NO: 24.

[0227] Embodiment 123 The method of any one of embodiments 117-122, wherein:(a) the CD19VH comprises an amino acid sequence with at least 99% sequence identity to SEQ ID NO: 19;WSGR Docket No. 69143-718.601(b) the CD19VL comprises an amino acid sequence with at least 99% sequence identity to SEQ ID NO: 20;(c) the CD3VH comprises an amino acid sequence with at least 99% sequence identity to SEQ ID NO: 21;(d) the CD3VL comprises an amino acid sequence with at least 99% sequence identity to SEQ ID NO: 22;(e) the CD20VH comprises an amino acid sequence with at least 99% sequence identity to SEQ ID NO: 23; or(f) the CD20VL comprises an amino acid sequence with at least 99% sequence identity to SEQ ID NO: 24.

[0228] Embodiment 124 Hie method of any one of embodiments 117-123, wherein:(a) the CD19VH comprises an amino acid sequence with at least 99% sequence identity to SEQ ID NO: 19;(b) the CD19VL comprises an amino acid sequence with at least 99% sequence identity to SEQ ID NO: 20;(c) the CD3VH comprises an amino acid sequence with at least 99% sequence identity to SEQ ID NO: 21;(d) the CD3VL comprises an amino acid sequence with at least 99% sequence identity to SEQ ID NO: 22;(e) the CD20VH comprises an amino acid sequence with at least 99% sequence identity to SEQ ID NO: 23; and(f) the CD20VL comprises an amino acid sequence with at least 99% sequence identity to SEQ ID NO: 24.

[0229] Embodiment 125 The method of any one of embodiments 117-124, wherein:(a) the CD19VH comprises the amino acid sequence of SEQ ID NO: 19;(b) the CD19VL comprises the amino acid sequence of SEQ ID NO: 20;(c) the CD3VH comprises the amino acid sequence of SEQ ID NO: 21;(d) the CD3VL comprises the amino acid sequence of SEQ ID NO: 22;(e) the CD20VH comprises the amino acid sequence of SEQ ID NO: 23; or(f) the CD20VL comprises the amino acid sequence of SEQ ID NO: 24.

[0230] Embodiment 126 The method of any one of embodiments 117-125, wherein:(a) the CD19VH comprises the amino acid sequence of SEQ ID NO: 19;(b) the CD19VL comprises the amino acid sequence of SEQ ID NO: 20;(c) the CD3VH comprises the amino acid sequence of SEQ ID NO: 21;(d) the CD3VL comprises the amino acid sequence of SEQ ID NO: 22;(e) the CD20VH comprises the amino acid sequence of SEQ ID NO: 23; and(f) the CD20VL comprises the amino acid sequence of SEQ ID NO: 24.

[0231] Embodiment 127 The method of any one of embodiments 117-126, wherein:(a) the CD19VH is operably linked to a first heavy chain constant domain (C1H);WSGR Docket No. 69143-718.601(b) the CD19VL is operably linked to a first light chain constant domain (CIL);(c) the CD3VH is operably linked to a second heavy chain constant domain (C₂ᴴ);(d) the CD3VL is operably linked to a second light chain constant domain (C₂ₗ);(e) the CD20VH is operably linked to a third heavy chain constant domain (C311); or(f) the CD20VL is operably linked to a third light chain constant domain (CSL).|0232] Embodiment 128 The method of any one of embodiments 117-127, wherein:(a) the CD19VH is operably linked to a first heavy chain constant domain (Cm);(b) the CD19VL is operably linked to a first light chain constant domain (CIL);(c) the CD3VH is operably linked to a second heavy chain constant domain (C₂ᴴ);(d) the CD3VL is operably linked to a second light chain constant domain (C₂ₗ);(e) the CD20VH is operably linked to a third heavy chain constant domain (C311); and(f) the CD20VL is operably linked to a third light chain constant domain (C IL).

[0233] Embodiment 129 The method of any one of embodiment 127 or 128, wherein:(a) the C₁ᴴ and C₁ₗ comprise a T cell receptor (TCR) α chain constant domain (Cα) and a TCR β chain constant domain (Cβ), respectively;(b) the C₁ᴴ and C₁ₗ comprise Cβ and Cα, respectively; or(c) the C₁ᴴ and C₁ₗ comprise an antibody heavy chain constant region CH1 domain and an antibody light chain constant region CL domain, respectively.

[0234] Embodiment 130 The method of any one of embodiments 127-129, wherein the C₁ᴴ and the C₁ₗ comprise Cα and Cβ, respectively.

[0235] Embodiment 131 The method of any one of embodiments 127-130, wherein the C1H and the C1L comprise Cβ and Cα, respectively.

[0236] Embodiment 132 The method of any one of embodiments 127-131, wherein the C1H and the C1L comprise CH1 domain and CL domain, respectively.

[0237] Embodiment 133 The method of any one of embodiments 127-132, wherein:(a) the C₂ᴴ and the C₂ₗ comprise Cα and Cβ, respectively;(b) the C₂ᴴ and the C₂ₗ comprise Cβ and Cα, respectively; or(c) the C₂ᴴ and the C₂ₗ comprise CH1 domain and CL domain, respectively.

[0238] Embodiment 134 The method of any one of embodiments 127-133, wherein the C₂ᴴ and the C₂ₗ comprise Cα and Cβ, respectively.

[0239] Embodiment 135 The method of any one of embodiments 127-134, wherein the C2H and the C2L comprise Cp and Ca, respectively.

[0240] Embodiment 136 The method of any one of embodiments 127-135, wherein the C2H and the C2L comprise CHI domain and CL domain, respectively.

[0241] Embodiment 137 The method of any one of embodiments 127-136, wherein:(a) the C₃ᴴ and the C₃ₗ comprise Cα and Cβ, respectively;(b) the C₃ᴴ and the C₃ₗ comprise Cβ and Cα, respectively; or(c) the C₃ᴴ and the C₃ₗ comprise CH1 domain and CL domain, respectively.WSGR Docket No. 69143-718.601

[0242] Embodiment 138 The method of any one of embodiments 127-137, wherein the C₃ᴴ and the C₃ₗ comprise Cα and Cβ, respectively.

[0243] Embodiment 139 The method of any one of embodiments 127-137, wherein the C₃ᴴ and the C₃ₗ comprise Cβ and Cα, respectively.

[0244] Embodiment 140 The method of any one of embodiments 127-137, wherein the C₃ᴴ and the C₃ₗ comprise CH1 domain and CL domain, respectively.

[0245] Embodiment 141 The method of any one of embodiments 127-140, wherein:(a) the C₁ᴴ and the C₁ₗ comprise Cβ and Cα, respectively;(b) the C₂ᴴ and the C₂ₗ comprise Cβ and Cα, respectively; and(c) the C₃ᴴ and the C₃ₗ comprise CH1 domain and CL domain, respectively.

[0246] Embodiment 142 The method of any one of embodiments 127-141, wherein:(a) Cacomprises an amino acid sequence with at least 90% sequence identity to SEQ ID NO: 31; (b) Cp comprises an amino acid sequence with at least 90% sequence identity to SEQ ID NO: 30; (c) CHI domain comprises an amino acid sequence with at least 90% sequence identity to SEQ ID NO: 36; or(d) CL domain comprises an amino acid sequence with at least 90% sequence identity to SEQ ID NO: 37.

[0247] Embodiment 143 The method of any one of embodiments 127-142, wherein:(a) Cacomprises an amino acid sequence with at least 90% sequence identity to SEQ ID NO: 31; (b) Cβ comprises an amino acid sequence with at least 90% sequence identity to SEQ ID NO: 30; (c) CH1 domain comprises an amino acid sequence with at least 90% sequence identity to SEQ ID NO: 36; and(d) CL domain comprises an amino acid sequence with at least 90% sequence identity to SEQ ID NO: 37.

[0248] Embodiment 144 The method of any one of embodiments 127-143, wherein:(a) Ca comprises an amino acid sequence with at least 95% sequence identity to SEQ ID NO: 31; (b) Cp comprises an amino acid sequence with at least 95 % sequence identity to SEQ ID NO: 30; (c) CHI domain comprises an amino acid sequence with at least 95% sequence identity to SEQ ID NO: 36; or(d) CL domain comprises an amino acid sequence with at least 95% sequence identity to SEQ ID NO: 37.

[0249] Embodiment 145 The method of any one of embodiments 127-144, wherein:(a) Ca comprises an amino acid sequence with at least 95% sequence identity to SEQ ID NO: 31; (b) Cp comprises an amino acid sequence with at least 95 % sequence identity to SEQ ID NO: 30; (c) CHI domain comprises an amino acid sequence with at least 95% sequence identity to SEQ ID NO: 36; and(d) CL domain comprises an amino acid sequence with at least 95% sequence identity to SEQ ID NO: 37.

[0250] Embodiment 146 The method of any one of embodiments 127-145, wherein:WSGR Docket No. 69143-718.601(a) Cocomprises an amino acid sequence with at least 99% sequence identity to SEQ ID NO: 31; (b) Cp comprises an amino acid sequence with at least 99% sequence identity to SEQ ID NO: 30; (c) CHI domain comprises an amino acid sequence with at least 99% sequence identity to SEQ ID NO: 36; or(d) CL domain comprises an amino acid sequence with at least 99% sequence identity to SEQ ID NO: 37.

[0251] Embodiment 147 The method of any one of embodiments 127-146, wherein:(a) Cacomprises an amino acid sequence with at least 99% sequence identity to SEQ ID NO: 31; (b) Cβ comprises an amino acid sequence with at least 99% sequence identity to SEQ ID NO: 30; (c) CHI domain comprises an amino acid sequence with at least 99% sequence identity to SEQ ID NO: 36; and(d) CL domain comprises an amino acid sequence with at least 99% sequence identity to SEQ ID NO: 37.

[0252] Embodiment 148 The method of any one of embodiments 127-147, wherein:(a) Cacomprises the amino acid sequence of SEQ ID NO: 31;(b) Cβ comprises the amino acid sequence of SEQ ID NO: 30;(c) CHI domain comprises the amino acid sequence of SEQ ID NO: 36; or(d) CL domain comprises the amino acid sequence of SEQ ID NO: 37.

[0253] Embodiment 149 The method of any one of embodiments 127-148, wherein:(a) Ca comprises the amino acid sequence of SEQ ID NO: 31;(b) Cp comprises the amino acid sequence of SEQ ID NO: 30;(c) CH1 domain comprises the amino acid sequence of SEQ ID NO: 36; and(d) CL domain comprises the amino acid sequence of SEQ ID NO: 37.

[0254] Embodiment 150 The method of any one of embodiments 127-149, wherein:(a) the C1H comprises the amino acid sequence of SEQ ID NO: 30;(b) the C₁ₗ comprises the amino acid sequence of SEQ ID NO: 31;(c) the C2H comprises the amino acid sequence of SEQ ID NO: 30;(d) the C2L comprises the amino acid sequence of SEQ ID NO: 31;(e) the C₃ᴴ comprises the amino acid sequence of SEQ ID NO: 36; and(f) the C₃ₗ comprises the amino acid sequence of SEQ ID NO: 37.

[0255] Embodiment 151 The method of any one of embodiments 127-150, wherein:(a) the CD19VH is covalently linked to the C1H directly or via a peptide linker;(b) the CD19VL is covalently linked to the C1L directly or via a peptide linker;(c) the CD3VH is covalently linked to the C2H directly or via a peptide linker;(d) the CD3VL is covalently linked to the C2L directly or via a peptide linker;(e) the CD20VH is covalently linked to the C₃ᴴ directly or via a peptide linker; or(f) the CD20VL is covalently linked to the CSL directly or via a peptide linker.

[0256] Embodiment 152 The method of any one of embodiments 127-151, wherein:(a) the CD19VH is covalently linked to the Cm directly;WSGR Docket No. 69143-718.601(b) the CD19VL is covalently linked to the CIL directly;(c) the CD3VH is covalently linked to the C2H directly;(d) the CD3VL is covalently linked to the C2L directly;(e) the CD20VH is covalently linked to the C₃ᴴ directly; or(f) the CD20VL is covalently linked to the C₃ₗ directly.

[0257] Embodiment 153 The method of any one of embodiments 127-151, wherein:(a) the CD19VH is covalently linked to the Cm directly;(b) the CD19VL is covalently linked to the CIL directly;(c) the CD3VH is covalently linked to the C₂ᴴ directly;(d) the CD3VL is covalently linked to the C2L directly;(e) the CD20VH is covalently linked to the C₃ᴴ directly; and(f) the CD20VL is covalently linked to the C₃ₗ directly.

[0258] Embodiment 154 The method of any one of embodiments 127-151, wherein:(a) the CD19VH is covalently linked to the Cm via a peptide linker;(b) the CD19VL is covalently linked to the C₁ₗ via a peptide linker;(c) the CD3VH is covalently linked to the C2H via a peptide linker;(d) the CD3VL is covalently linked to the C2L via a peptide linker;(e) the CD20VH is covalently linked to the C₃ᴴ via a peptide linker; or(f) the CD20VL is covalently linked to the CSL via a peptide linker.

[0259] Embodiment 155 The method of any one of embodiments 127-151, wherein:(a) the CD19VH is covalently linked to the CIH via a peptide linker;(b) the CD19VL is covalently linked to the CIL via a peptide linker;(c) the CD3 VH is covalently linked to the C2H via a peptide linker;(d) the CD3VL is covalently linked to the C₂ₗ via a peptide linker;(e) the CD20VH is covalently linked to the CSH via a peptide linker; and(f) the CD20VL is covalently linked to the CSL via a peptide linker.

[0260] Embodiment 156 The method of any one of embodiments 1-155, wherein the antibody or antigen-binding portion thereof further comprises a first heavy chain (HC1), a second heavy chain (HC2), a first light chain (LC1), a second light chain (LC2), or a third light chain (LC3).

[0261] Embodiment 157 The method of any one of embodiments 1-155, wherein the antibody or antigen-binding portion thereof further comprises the first heavy chain (HC 1), the second heavy chain (HC2), the first light chain (LC1), the second light chain (LC2), and the third light chain (LC3).

[0262] Embodiment 158 The method of any one of embodiments 1-157, wherein the antibody or antigen-binding portion thereof further comprises a fragment crystallizable (Fc) region.

[0263] Embodiment 159 The method of any one of embodiments 1-158, wherein the antibody or antigen-binding portion thereof further comprises an immunoglobulin (Ig) G, IgA, IgM, IgE, or IgD.

[0264] Embodiment 160 The method of any one of embodiments 1-159, w herein the antibody or antigen-binding portion thereof further comprises an IgGl, IgG2, IgG3, or IgG4.WSGR Docket No. 69143-718.601

[0265] Embodiment 161 The method of any one of embodiments 1-160, wherein the antibody or antigen-binding portion thereof further comprises a human IgG1, IgG2, IgG3, or IgG4.

[0266] Embodiment 162 The method of any one of embodiments 1-161, whe...

Claims

WSGR Docket No. 69143-718.601CLAIMS WHAT IS CLAIMED IS:

1. A method for treating an autoimmune disease or disorder in a subject, comprising administering to the subject a therapeutically effective amount of (i) an antibody or antigen-binding portion thereof comprising a CD19 binding moiety, a CD3 binding moiety and a CD20 binding moiety, or (ii) one or more polynucleotide encoding the antibody or antigen-binding portion thereof; wherein:(a) the CD19 binding moiety comprises a heavy chain complementarity determining region (HCDR) 1, a HCDR2 and a HCDR3 comprising the amino acid sequences of SEQ ID NOs: 1, 2 and 3, respectively, and a light chain complementarity determining region (LCDR) 1, a LCDR2 and a LCDR3 comprising the amino acid sequences of SEQ ID NOs: 4, 5 and 6, respectively;(b) the CD3 binding moiety comprises a HCDR1, a HCDR2 and a HCDR3 comprising the amino acid sequences of SEQ ID NOs: 7, 8 and 9, respectively, and a LCDR1, a LCDR2 and a LCDR3 comprising the amino acid sequences of SEQ ID NOs: 10, 11 and 12, respectively; and(c) the CD20 binding moiety comprises a HCDR1, a HCDR2 and a HCDR3 comprising the amino acid sequences of SEQ ID NOs: 13, 14 and 15, respectively, and a LCDR1, a LCDR2 and a LCDR3 comprising the amino acid sequences of SEQ ID NOs: 16, 17 and 18, respectively.

2. The method of claim 1, wherein the autoimmune disease or disorder comprises an autoantibody- driven disease.

3. The method of claim 1, wherein tire autoimmune disease or disorder comprises a disease mediated by an autoantibody.

4. The method of claim 1, wherein the autoimmune disease or disorder comprises a disease mediated by a B cell, a plasmablast, or a plasma cell.

5. The method of claim I, wherein the autoimmune disease or disorder comprises a disease mediated by a mature B cell, a memory B cell, or an activated B cell.

6. The method of claim 1, wherein the autoimmune disease or disorder comprises allergy, antibody- mediated rejection, alloantibodies, a disease related to or mediated by an alloantibody, amyloidosis, anti-glomerular basement membrane (GBM) (Goodpasture Syndrome), anti-N- methyl-D-aspartate receptor (NMDA) encephalitis (anti-NMDA-R Encephalitis), anti-neutrophil cytoplasmic autoantibody-associated vasculitis (ANCA vasculitis), antiphospholipid antibody syndrome, anti synthetase Syndrome, atopic dermatitis, autoimmune hepatitis, autoimmune necrotizing myopathy, Behcet’s disease, Bullous Pemphigoid, Celiac disease. Chronic Inflammatory Demyelinating Polyneuropathy (CIDP), Crohn’s disease, dilated cardiomyopathy. Graves, Guillain Barre Syndrome, Hidradenitis Suppurativa, IgA Nephropathy, Immunoglobulin G4-related disease (IgG4-RD), immune vasculitis (IgA), immune thrombocytopenia (ITP), LongWSGR Docket No. 69143-718.601COVID, Lupus Nephritis, Membranous Nephropathy, microscopic polyangiitis, multiple sclerosis (MS) - primary progressive multiple sclerosis (MS-PPMS), multiple sclerosis (MS) -relapsing¬ remitting multiple sclerosis (MS-RRMS), Myasthenia Gravis, myositis-dermatomyositis, myositis-inclusion body, myositis-polymyositis, myositis- immune-mediated necrotizing myositis, neuromyelitis optica spectrum disorder (NMOSD), Pemphigus Vulgaris, polyneuropathy, organomegaly, endocrinopathy, M-protein and skin changes (POEMS) syndrome, Postural Orthostatic Tachycardia Syndrome (POTS), Polyarteritis Nodosa, Primary Biliary Cirrhosis, Primary Sclerosing Cholangitis, Psoriasis, Psoriatic Arthritis, Raynaud’s Syndrome, Reactive Arthritis, rheumatoid arthritis, scleroderma or systemic sclerosis, Sjogren’s Syndrome, Stiff Person Syndrome, Type 1 diabetes, Thyroid eye disease, tumor progression, or ulcerative colitis.

7. The method of claim 6, wherein the subject is a human.

8. The method of claim 6, wherein the subject is a human and is diagnosed with the autoimmune disease or disorder or suspected to have the autoimmune disease or disorder.

9. The method of claim 1, wherein the therapeutically effective amount of the antibody or antigenbinding portion thereof is calculated based on a biomarker.

10. The method of claim 1, wherein the method further comprises measuring a biomarker in the subject.

11. The method of claim 10, wherein the biomarker comprises a B cell, a plasmablast, a plasma cell, an autoantibody, or an immunoglobulin (Ig).

12. The method of claim 10, wherein the biomarker comprises a mature B cell, a memory B cell, or an activated B cell.

13. The method of claim 10, wherein the biomarker comprises a free kappa light chain or a free lambda light chain.

14. The method of claim 11, wherein the immunoglobulin comprises IgD, IgG, IgA, or IgM.

15. The method of claim 1, wherein the therapeutically effective amount is calculated based on an amount of the biomarker.

16. The method of claim 1, wherein the therapeutically effective amount is calculated based on an amount of the biomarker in tonsil, mucosal lamina propria (LP), blood, spleen, lymph node, or bone marrow.

17. The method of claim 1, wherein the therapeutically effective amount is calculated based on a reduction in the amount of the biomarker in the tonsil, mucosal LP, blood, spleen, lymph node, or bone marrow after the administering,18. The method of claim 1, wherein the antibody or antigen-binding portion thereof is administered subcutaneously, intramuscularly or intravenously.

19. The method of claim 1, wherein the administering results in elimination or reduction of a B cell, a plasmablast, or a plasma cell,20. The method of claim 1, wherein the administering results in elimination or reduction of a mature B cell, a memory B cell, or an activated B cell.WSGR Docket No. 69143-718.60121. The method of claim 1, wherein the administering results in elimination or reduction of an autoantibody.

22. The method of claim 1, wherein the administering results in elimination or reduction of the B cell, the plasmablast, or the plasma cell through antibody-dependent cellular cytotoxicity (ADCC), antibody-dependent cellular phagocytosis (ADCP), and / or complement-dependent cytotoxicity (CDC).

23. The method of claim 1, wherein the administering results in elimination or reduction of the B cell, the plasmablast, or the plasma cell and the B cell, the plasmablast, or the plasma cell expresses CD 19.

24. The method of claim 1, wherein the administering results in elimination or reduction of the B cell, the plasmablast, or the plasma cell and the B cell, the plasmablast, or the plasma cell expresses CD20.

25. The method of claim 1, wherein the administering results in elimination or reduction of the B cell, the plasmablast, or the plasma cell and the B cell, the plasmablast, or the plasma cell expresses CD19 and CD20, or CD 138.

26. The method of claim 1, further comprising revaccinating the subject.

27. The method of claim 1, further comprising administering to the subject a pharmaceutical composition comprising the antibody or antigen-binding fragment thereof or the one or more polynucleotide encoding the antibody or antigen-binding portion thereof, and a pharmaceutically acceptable earner or excipient,28. The method of claim 1, wherein:(a) the CD19 binding moiety comprises a heavy chain variable region (CD19VH) and a light chain variable region (CD19VL);(b) the CD3 binding moiety comprises a heavy chain variable region (CD3 VH) and a light chain variable region (CD3VL); and(c) the CD20 binding moiety comprises a heavy chain variable region (CD20VH) and a light chain variable region (CD20VL).

29. The method of claim 28, wherein the antibody or antigen-binding portion thereof further comprises a first binding arm and a second binding arm, wherein the first binding arm comprises the CD 19 binding moiety and the CD3 binding moiety and the second binding arm comprises the CD20 binding moiety.

30. The method of claim 28, wherein:(a) the CD19VH comprises an amino acid sequence with at least 90% sequence identity to SEQ ID NO: 19;(b) the CD19VL comprises an amino acid sequence with at least 90% sequence identity to SEQ ID NO: 20;(c) the CD3VH comprises an amino acid sequence with at least 90% sequence identity to SEQ ID NO: 21;WSGR Docket No. 69143-718.601(d) the CD3VL comprises an amino acid sequence with at least 90% sequence identity to SEQ ID NO: 22;(e) the CD20VH comprises an amino acid sequence with at least 90% sequence identity to SEQ ID NO: 23; and(f) the CD20VL comprises an amino acid sequence with at least 90% sequence identity to SEQ ID NO: 24.

31. The method of claim 28, wherein:(a) the CD19VH comprises the amino acid sequence of SEQ ID NO: 19;(b) the CD19VL comprises the amino acid sequence of SEQ ID NO: 20;(c) the CD3VH comprises the amino acid sequence of SEQ ID NO: 21;(d) the CD3VL comprises the amino acid sequence of SEQ ID NO: 22;(e) the CD20VH comprises the amino acid sequence of SEQ ID NO: 23; and(f) the CD20VL comprises the amino acid sequence of SEQ ID NO: 24.

32. The method of claim 28, wherein:(a) the CD19VH is operably linked to a first heavy chain constant domain (CH);(b) the CD19VL is operably linked to a first light chain constant domain (CL);(c) the CD3VH is operably linked to a second heavy chain constant domain (CH);(d) the CD3VL is operably linked to a second light chain constant domain (CL);(e) the CD20VH is operably linked to a third heavy chain constant domain (CH); or(f) the CD20VL is operably linked to a third light chain constant domain (CL).

33. The method of claim 28, wherein:(a) the GDI 9VH is operably linked to a first heavy chain constant domain (C1H);(b) the CD19VL is operably linked to a first light chain constant domain (CL);(c) the CD3VH is operably linked to a second heavy chain constant domain (CH);(d) the CD3VL is operably linked to a second light chain constant domain (CL);(e) the CD20VH is operably linked to a third heavy chain constant domain (CH); and(f) the CD20VL is operably linked to a third light chain constant domain (CL).

34. The method of claim 32, wherein:(a) the C1H and CL comprise a T cell receptor (TCR) α chain constant domain (Cα) and a TCR β chain constant domain (Cβ), respectively;(b) the C1H and CL comprise Cβ and Cα, respectively; or(c) the C1H and CL comprise an antibody heavy chain constant region CH1 domain and an antibody light chain constant region CL domain, respectively,35. The method of claim 32, wherein the C1H and the CL comprise Cα and Cβ, respectively.

36. The method of claim 32, wherein the C1H and the CL comprise Cβ and Cα, respectively.

37. The method of claim 32, wherein the C1H and the CL comprise CH1 domain and CL domain, respectively.

38. The method of claim 32, wherein:(a) the C2H and the C2L comprise Cα and Cβ, respectively;WSGR Docket No. 69143-718.601(b) the C2H and the C2L comprise Cβ and Cα, respectively; or(c) the C2H and the C2L comprise CHI domain and CL domain, respectively.

39. The method of claim 32, wherein the C2H and the C2L comprise Cα and Cβ, respectively.

40. The method of claim 32, wherein the C2H and the C2L comprise Cβ and Cα, respectively.

41. The method of claim 32, wherein the C2H and the C2L comprise CH1 domain and CL domain, respectively.

42. The method of claim 32, wherein:(a) the C3H and the C3L comprise Cα and Cβ, respectively;(b) the C3H and the C3L comprise Cβ and Cα, respectively; or(c) the C₃ᴴ and the C₃ₗ comprise CH1 domain and CL domain, respectively.

43. The method of claim 32, wherein the C3H and the C3L comprise Cα and Cβ, respectively.

44. The method of claim 32, wherein the C3H and the C3L comprise Cβ and Cα, respectively.

45. The method of claim 32, wherein the C3H and the C3L comprise CH1 domain and CL domain, respectively.

46. The method of claim 32, wherein:(a) the C1H and the C1L comprise Cβ and Cα, respectively;(b) the C2H and the C2L comprise Cβ and Cα, respectively; and(c) the C3H and the C3L comprise CH1 domain and CL domain, respectively.

47. The method of claim 34, wherein:(a) Cacomprises an amino acid sequence with at least 90% sequence identity to SEQ ID NO: 31; (b) Cp comprises an amino acid sequence with at least 90% sequence identity to SEQ ID NO: 30; (c) CH1 domain comprises an amino acid sequence with at least 90% sequence identity to SEQ ID NO: 36; and(d) CL domain comprises an amino acid sequence with at least 90% sequence identity to SEQ ID NO: 37.

48. The method of claim 34, wherein:(a) Cacomprises the amino acid sequence of SEQ ID NO: 31;(b) Cp comprises the amino acid sequence of SEQ ID NO: 30;(c) CH1 domain comprises the amino acid sequence of SEQ ID NO: 36; and(d) CL domain comprises the amino acid sequence of SEQ ID NO: 37.

49. The method of claim 34, wherein:(a) the C1H comprises the amino acid sequence of SEQ ID NO: 30;(b) the C1L comprises the amino acid sequence of SEQ ID NO: 31;(c) the C2H comprises the amino acid sequence of SEQ ID NO: 30;(d) the C2L comprises the amino acid sequence of SEQ ID NO: 31;(e) the C3H comprises the amino acid sequence of SEQ ID NO: 36; and(f) the C3L comprises the amino acid sequence of SEQ ID NO: 37,50. The method of claim 32, wherein:(a) the CD19VH is covalently linked to the C1H directly or via a peptide linker;WSGR Docket No. 69143-718.601(b) the CD19VL is covalently linked to the C1L directly or via a peptide linker;(c) the CD3VH is covalently linked to the C2H directly or via a peptide linker;(d) the CD3VL is covalently linked to the C2L directly or via a peptide linker;(e) the CD20VH is covalently linked to the C₃ᴴ directly or via a peptide linker; or(f) the CD20VL is covalently linked to the C3L directly or via a peptide linker.

51. The method of claim 32, wherein the antibody or antigen-binding portion thereof further comprises the first heavy chain (HC1), the second heavy chain (HC2), the first light chain (LC1), the second light chain (LC2), and the third light chain (LC3),52. The method of claim 51, wherein the an tibody or antigen-binding portion thereof further comprises a fragment crystallizable (Fc) region.

53. The method of claim 52, wherein the antibody or antigen-binding portion thereof further comprises an immunoglobulin (Ig) G, IgA, IgM, IgE, or IgD.

54. The method of claim 53, wherein the antibody or antigen-binding portion thereof further comprises an IgG1, IgG2, IgG3, or IgG4.

55. The method of claim 53, wherein the antibody or antigen-binding portion thereof further comprises an IgG4.

56. The method of claim 1, wherein the CD19 binding moiety, the CD3 binding moiety, or the CD20 binding moiety comprises a fragment antigen-binding (Fab) region, a Fab’, a F(ab’)2, or single chain variable fragment (scFv).

57. The method of claim 56, wherein the CD19 binding moiety, the CD3 binding moiety, and the CD20 binding moiety each comprises a Fab region.

58. The method of claim 51, wherein HC1, HC2, LC1, LC2 and LC3 comprise domains operably linked, from the amino terminus to the carboxyl terminus, in the following formats:(a) CD19VH-Cβ-CD3VL-Cα-Fc, CD20VH-CH1-Fc, CD19VL-Cα, CD3VH-Cβ, and CD20VL-CL, respectively;(b) CD19VL-Cα-CD3VH-Cβ-Fc, CD20VH-CH1-Fc, CD19VH-Cβ, CD3VL-Cα, and CD20VL-CL, respectively;(c) CD3VH-Cβ-CD19VL-Cα-Fc, CD20VH-CH1-Fc, CD3VL-Cα, CD19VH-Cβ, and CD20VL-CL, respectively; or(d) CD3VL-Cα-CD19VH-Cβ-Fc, CD20VH-CH1-Fc, CD3VH-Cβ, CD19VL-Cα, and CD20VL-CL, respectively.

59. The method of claim 51, wherein HC1, HC2, LC1, LC2 and LC3 comprise domains operably linked, from the amino terminus to the carboxyl terminus, in the following formats: CD19VH-Cβ-CD3VL-Cα-Fc, CD20VH-CH1-Fc, CD19VL-Cα, CD3VH-Cβ, and CD20VL-CL, respectively.

60. The method of claim 58, wherein:(a) CD19VH-Cβ is covalently linked to CD3VL-Cα-Fc directly or via a peptide linker;(b) CD19VL-Cα is covalently linked to CD3VH-Cβ-Fc directly or via a peptide linker;(c) CD3VH-Cβ is covalently linked to CD19VL-Cα-Fc directly or via a peptide linker; or (d) CD3VL-Cα is covalently linked to CD19VH-Cβ-Fc directly or via a peptide linker.WSGR Docket No. 69143-718.60161. The method of claim 60, wherein the peptide linker comprises a glycine (G) and serine (S) linker comprising (GS)n, (GGS)n, (GGGS)n, (GGGGS)n, (GGSG)n, (GGGSS)n, wherein n is an integer of 1-9.

62. The method of claim 60, wherein the peptide linker compri ses SEQ ID NO: 34.

63. The method of claim 60, wherein CD19VH-Cβ is covalently linked to CD3VL-Cα-Fc via the peptide linker comprising SEQ ID NO: 34.

64. The method of claim 60, wherein:(a) CD19VH-Cβ-CD3VL-Cα is covalently linked to the Fc region directly, via a hinge region, or via a E / K coil linker;(b) CD20VH-CH1 is covalently linked to the Fc region directly, via a hinge region, or via a E / K coil linker;(c) CD19VL-Cα-CD3VH-Cβ is covalently linked to the Fc region directly, via a hinge region, or via a E / K coil linker;(d) CD3VH-Cβ-CD19VL-Cα is covalently linked to the Fc region directly, via a hinge region, or via a E / K coil linker; or(e) CD3VL-Cα-CD19VH-Cβ is covalently linked to the Fc region directly, via a hinge region, or via a E / K coil linker.

65. The method of claim 64, wherein:(a) CD19VH-Cβ.CD3VL-Cα is covalently linked to the Fc region via the hinge region or via a E / K coil linker; and(a) CD20VH-CH1 is covalently linked to the Fc region via the hinge region or via a E / K coil linker.

66. The method of claim 65, wherein:(a) CD19VH-Cp. CD3 VL-Cci is covalently linked to the Fc region via the hinge region comprising SEQ ID NO: 33; and(b) CD20VH-CH1 is covalently linked to the Fc region via the hinge region comprising SEQ ID NO: 33.

67. The method of claim 58, wherein:(a) CD 19VH-Cp associates with CD 19VL-Cato form the CD 19 binding moiety’;(b) CD3VL-Cα associates with CD3VH-Cβ to form the CD3 binding moiety; and(c) CD20VH-CH1 associates with CD20VL-CL to form the CD20 binding moiety.

68. The method of claim 58, wherein Cα and Cβ associate to form a dimer via a bond or an interaction between Cα and Cβ.

69. The method of claim 58, wherein Caor Cp comprises an amino acid modification that results in a disulfide bond formed between Caand Cp, wherein the disulfide bond improves the stability of the interface between Cα and Cβ.

70. The method of claim 58, wherein the Fc region of the antibody or antigen-binding portion thereof comprises a first amino acid mutation that reduces or eliminates antibody -dependent cellular cytotoxicity (ADCC), antibody -dependent cellular phagocytosis (ADCP), or complement-WSGR Docket No. 69143-718.601dependent cytotoxicity (CDC) or binding of the antibody or antigen-binding portion thereof to a Fc-gamma receptor (FcyR).

71. The method of claim 70, wherein:(a) the Fc region of the first heavy chain (HC1) comprises the first amino acid mutation comprising F234A and L235A; and(b) the Fc region of the second heavy chain (HC2) comprises the first amino acid mutation comprising F234A and L235A.

72. The method of claim 71, wherein the Fc region of the first heavy chain (HC 1) or second heavy chain (HC2) comprises a second amino acid mutation that results in knob-in to-hole substitution in the first heavy chain (HC1) or second heavy chain (HC2).

73. The method of claim 72, wherein the second amino acid mutation of the Fc region comprises:(a) a substitution of serine (S) with cysteine (C) at amino acid residue 354 according to the EU numbering (S354C);(b) a substitution of threonine (T) with tryptophan (W) at amino acid residue 366 according to the EU numbering (T366W);(c) a substitution of tyrosine (Y) with cysteine (C) at amino acid residue 349 according to the EU numbering (Y349C);(d) a substitution of threonine (T) with serine (S) at amino acid residue 366 according to the EU numbering (T366S);(e) a substitution of leucine (L) with alanine (A) at amino acid residue 368 according to the EU numbering (L368A); or(f) a substitution of tyrosine (Y) with valine (V) at amino acid residue 407 according to the EU numbering (Y407V).

74. The method of claim 72, wherein:(a) the Fc region of the first heavy chain (HC1) comprises the second amino acid mutation comprising S354C and T366W; and(b) the Fc region of the second heavy chain (HC2) comprises the second amino acid mutation comprising Y349C, T366S, L368A, and Y407V.

75. The method of claim 72, wherein:(a) the Fc region of the first heavy chain (HC1) comprises the second amino acid mutation comprising Y349C, T366S, L368A, and Y407V; and(b) the Fc region of the second heavy chain (HC2) comprises the second amino acid mutation comprising S354C and T366W.

76. The method of claim 73, wherein:(a) the Fc region of the first heavy chain (HC1) comprises the first amino acid mutation comprising F234A and L235A and the second amino acid mutation comprising S354C and T366W; andWSGR Docket No. 69143-718.601(b) the Fc region of the second heavy chain (HC2) comprises the first amino acid mutation comprising F234A and L235A and the second amino acid mutation comprising Y349C, T366S, L368A, and Y407V.

77. The method of claim 73, wherein:(a) the Fc region of the first heavy chain (HC1) comprises the first amino acid mutation comprising F234A and L235A and the second amino acid mutation comprising Y349C, T366S, L368A, and Y407V; and(b) the Fc region of the second heavy chain (HC2) comprises the first amino acid mutation comprising F234A and L235A and the second amino acid mutation comprising S354C and T366W.

78. The method of claim 73, wherein the Fc region of the first heavy chain (HC1) or second heavy chain (HC2) comprises a third amino acid mutation comprising:(a) a substitution of serine (S) with proline (P) at amino acid residue 228 according to the EU numbering (S228P);(b) a substitution of methionine (M) with tyrosine (Y) at amino acid residue 252 according to the EU numbering (M252Y);(c) a substitution of serine (S) with threonine (T) at amino acid residue 254 according to the EU numbering (S254T); or(d) a substitution of threonine (T) with glutamic acid (E) at amino acid residue 256 according to the EU numbering (T256E).

79. The method of claim 78, wherein the Fc region of the first heavy chain (HC1) comprises a third amino acid mutation comprising S228P, M252Y, S254T, or T256E.

80. The method of claim 78, wherein the Fc region of the second heavy chain (HC2) comprises a third amino acid mutation comprising S228P, M252Y, S254T, or T256E.

81. The method of claim 78, wherein:(a) the Fc region of the first heavy chain (HC1) comprises an amino acid sequence with at least 90% sequence identity to SEQ ID NO: 32; and(b) the Fc region of the second heavy chain (HC2) comprises an amino acid sequence with at least 90% sequence identity to SEQ ID NO: 35,82. The method of claim 78, wherein:(a) the Fc region of the first heavy chain (HC1) comprises the amino acid sequence of SEQ ID NO: 32; and(b) the Fc region of the second heavy chain (HC2) comprises the amino acid sequence of SEQ ID NO: 35.

83. The method of claim 51, wherein:(a) HC1 comprises an amino acid sequence with at least 90% sequence identity to SEQ ID NO:25;(b) HC2 comprises an amino acid sequence with at least 90% sequence identity to SEQ ID NO:26;WSGR Docket No. 69143-718.601(c) LC1 comprises an amino acid sequence with at least 90% sequence identity to SEQ ID NO:27;(d) LC2 comprises an amino acid sequence with at least 90% sequence identity to SEQ ID NO:28; and(e) LC3 comprises an amino acid sequence with at least 90% sequence identity to SEQ ID NO:29.

84. The method of claim 51, wherein:(a) HC1 comprises the amino acid sequence of SEQ ID NO: 25;(b) HC2 comprises the amino acid sequence of SEQ ID NO: 26;(c) LC1 comprises the amino acid sequence of SEQ ID NO: 27;(d) LC2 comprises the amino acid sequence of SEQ ID NO: 28; and(e) LC3 comprises the amino acid sequence of SEQ ID NO: 29.

Images