A bispecific antibody comprising a first antigen-binding domain that binds human CD3, a second antigen-binding domain that binds human CD20, and a chimeric heavy chain constant region tethered to each of the first and second antigen-binding domains, wherein the first antigen-binding domain (A1) that specifically binds human CD3 comprises three heavy chain complementarity determining regions (HCDR1, HCDR2, HCDR3) and three light chain complementarity determining regions (LCDR1, LCDR2, LCDR3), wherein (i) A1-HCDR1 comprises the amino acid sequence of SEQ ID NO: 12; (ii) A1-HCDR2 comprises the amino acid sequence of SEQ ID NO: 14; (iii) A1-HCDR3 comprises the amino acid sequence of SEQ ID NO: 16; (iv) A1-LCDR1 comprises the amino acid sequence of SEQ ID NO: 20; (v) A1-LCDR2 comprises the amino acid sequence of SEQ ID NO: 22; and (vi) A1-LCDR3 comprises the amino acid sequence of SEQ ID NO: 24, wherein the second antigen-binding domain (A2) that specifically binds human CD20 comprises three heavy chain complementarity determining regions (HCDR1, HCDR2, HCDR3) and three light chain complementarity determining regions (LCDR1, LCDR2, LCDR3), wherein (i) A2-HCDR1 comprises the amino acid sequence of SEQ ID NO: 4; (ii) A2-HCDR2 comprises the amino acid sequence of SEQ ID NO: 6; (iii) A2-HCDR3 comprises the amino acid sequence of SEQ ID NO: 8; (iv) A2-LCDR1 comprises the amino acid sequence of SEQ ID NO: 20; (v) A2-LCDR2 comprises the amino acid sequence of SEQ ID NO: 22; and (vi) A2-LCDR3 comprises the amino acid sequence of SEQ ID NO: 24, wherein the chimeric heavy chain constant region comprises: (i) a human IgG1 or a human IgG4 upper hinge amino acid sequence from positions 216 to 227 (EU numbering); (ii) a human IgG2 lower hinge amino acid sequence comprising PCPAPPVA (SEQ ID NO: 52) from positions 228 to 236 (EU numbering); (iii) a human IgG1 CH1 domain and a human IgG1 CH3 domain, or a human IgG4 CH1 domain and a human IgG4 CH3 domain; and (iv) a human IgG4 CH2 domain amino acid sequence from positions 237 to 340 (EU numbering); and wherein the bispecific antibody exhibits a higher binding affinity for human FcyRIIA relative to human FcyRIIB, and exhibits little or no detectable binding affinity to human FcyRI and human FcyRIII, as measured in a surface plasmon resonance assay. (i) A1-HCDR1 comprises the amino acid sequence of SEQ ID NO: 12; (ii) A1-HCDR2 comprises the amino acid sequence of SEQ ID NO: 14; (iii) A1-HCDR3 comprises the amino acid sequence of SEQ ID NO: 16; (iv) A1-LCDR1 comprises the amino acid sequence of SEQ ID NO: 20; (v) A1-LCDR2 comprises the amino acid sequence of SEQ ID NO: 22; and (vi) A1-LCDR3 comprises the amino acid sequence of SEQ ID NO: 24, (i) A2-HCDR1 comprises the amino acid sequence of SEQ ID NO: 4; (ii) A2-HCDR2 comprises the amino acid sequence of SEQ ID NO: 6; (iii) A2-HCDR3 comprises the amino acid sequence of SEQ ID NO: 8; (iv) A2-LCDR1 comprises the amino acid sequence of SEQ ID NO: 20; (v) A2-LCDR2 comprises the amino acid sequence of SEQ ID NO: 22; and (vi) A2-LCDR3 comprises the amino acid sequence of SEQ ID NO: 24, (i) a human IgG1 or a human IgG4 upper hinge amino acid sequence from positions 216 to 227 (EU numbering); (ii) a human IgG2 lower hinge amino acid sequence comprising PCPAPPVA (SEQ ID NO: 52) from positions 228 to 236 (EU numbering); (iii) a human IgG1 CH1 domain and a human IgG1 CH3 domain, or a human IgG4 CH1 domain and a human IgG4 CH3 domain; and (iv) a human IgG4 CH2 domain amino acid sequence from positions 237 to 340 (EU numbering); and <EOS>