An antibody or antigen-binding fragment of an antibody comprising a heavy chain variable region comprising the 2nd through 119th amino acid residues of SEQ ID NO: 22 and a light chain variable region comprising the 137th through 243rd amino acid residues of SEQ ID NO: 22; a heavy chain variable region comprising the 2nd through 119th amino acid residues of SEQ ID NO: 25 and a light chain variable region comprising the 135th through 241st amino acid residues of SEQ ID NO: 25; a heavy chain variable region comprising the 2nd through 119th amino acid residues of SEQ ID NO: 64 and a light chain variable region comprising the 135th through 241st amino acid residues of SEQ ID NO: 64; a heavy chain variable region comprising the 2nd through 119th amino acid residues of SEQ ID NO: 66 and a light chain variable region comprising the 135th through 243rd amino acid residues of SEQ ID NO: 66; a heavy chain variable region comprising the 2nd through 119th amino acid residues of SEQ ID NO: 68 and a light chain variable region comprising the 135th through 243rd amino acid residues of SEQ ID NO: 68; a heavy chain variable region comprising the 2nd through 119th amino acid residues of SEQ ID NO: 70 and a light chain variable region comprising the 135th through 243rd amino acid residues of SEQ ID NO: 70; a heavy chain variable region comprising the 2nd through 119th amino acid residues of SEQ ID NO: 72 and a light chain variable region comprising the 135th through 243rd amino acid residues of SEQ ID NO: 72; a heavy chain variable region comprising the 2nd through 119th amino acid residues of SEQ ID NO: 74 and a light chain variable region comprising the 135th through 243rd amino acid residues of SEQ ID NO: 74; a heavy chain variable region comprising the 2nd through 119th amino acid residues of SEQ ID NO: 80 and a light chain variable region comprising the 135th through 243rd amino acid residues of SEQ ID NO: 80; or a heavy chain variable region comprising the 2nd through 119th amino acid residues of SEQ ID NO: 82 and a light chain variable region comprising the 135th through 243rd amino acid residues of SEQ ID NO: 82, wherein the antibody or antigen-binding fragment binds to human CD3 and to cynomolgus monkey CD3. a heavy chain variable region comprising the 2nd through 119th amino acid residues of SEQ ID NO: 22 and a light chain variable region comprising the 137th through 243rd amino acid residues of SEQ ID NO: 22; a heavy chain variable region comprising the 2nd through 119th amino acid residues of SEQ ID NO: 25 and a light chain variable region comprising the 135th through 241st amino acid residues of SEQ ID NO: 25; a heavy chain variable region comprising the 2nd through 119th amino acid residues of SEQ ID NO: 64 and a light chain variable region comprising the 135th through 241st amino acid residues of SEQ ID NO: 64; a heavy chain variable region comprising the 2nd through 119th amino acid residues of SEQ ID NO: 66 and a light chain variable region comprising the 135th through 243rd amino acid residues of SEQ ID NO: 66; a heavy chain variable region comprising the 2nd through 119th amino acid residues of SEQ ID NO: 68 and a light chain variable region comprising the 135th through 243rd amino acid residues of SEQ ID NO: 68; a heavy chain variable region comprising the 2nd through 119th amino acid residues of SEQ ID NO: 70 and a light chain variable region comprising the 135th through 243rd amino acid residues of SEQ ID NO: 70; a heavy chain variable region comprising the 2nd through 119th amino acid residues of SEQ ID NO: 72 and a light chain variable region comprising the 135th through 243rd amino acid residues of SEQ ID NO: 72; a heavy chain variable region comprising the 2nd through 119th amino acid residues of SEQ ID NO: 74 and a light chain variable region comprising the 135th through 243rd amino acid residues of SEQ ID NO: 74; a heavy chain variable region comprising the 2nd through 119th amino acid residues of SEQ ID NO: 80 and a light chain variable region comprising the 135th through 243rd amino acid residues of SEQ ID NO: 80; or a heavy chain variable region comprising the 2nd through 119th amino acid residues of SEQ ID NO: 82 and a light chain variable region comprising the 135th through 243rd amino acid residues of SEQ ID NO: 82,