A CD33 specific antibody, comprising: (i) a heavy chain variable region comprising an amino acid sequence represented by: and a light chain variable region comprising an amino acid sequence represented by: (ii) a heavy chain variable region comprising an amino acid sequence represented by: and a light chain variable region comprising an amino acid sequence represented by: (iii) a heavy chain variable region comprising an amino acid sequence represented by: and a light chain variable region comprising an amino acid sequence represented by: (iv) a heavy chain variable region comprising an amino acid sequence represented by: and a light chain variable region comprising an amino acid sequence represented by: (v) a heavy chain variable region comprising an amino acid sequence represented by: and a light chain variable region comprising an amino acid sequence represented by: (vi) a heavy chain variable region comprising an amino acid sequence represented by: and a light chain variable region comprising an amino acid sequence represented by: (vii) a heavy chain variable region comprising an amino acid sequence represented by: and a light chain variable region comprising an amino acid sequence represented by: (viii) a heavy chain variable region comprising an amino acid sequence represented by: and a light chain variable region comprising an amino acid sequence represented by: (ix) a heavy chain variable region comprising an amino acid sequence represented by: and a light chain variable region comprising an amino acid sequence represented by: (x) a heavy chain variable region comprising an amino acid sequence represented by: and a light chain variable region comprising an amino acid sequence represented by: (xi) a heavy chain variable region comprising an amino acid sequence represented by: and a light chain variable region comprising an amino acid sequence represented by: (xii) a heavy chain variable region comprising an amino acid sequence represented by: and a light chain variable region comprising an amino acid sequence represented by: (xiii) a heavy chain variable region comprising an amino acid sequence represented by: and a light chain variable region comprising an amino acid sequence represented by: (xiv) a heavy chain variable region comprising an amino acid sequence represented by: and a light chain variable region comprising an amino acid sequence represented by: or (xv) a heavy chain variable region comprising an amino acid sequence represented by: and a light chain variable region comprising an amino acid sequence represented by: (i) a heavy chain variable region comprising an amino acid sequence represented by: and a light chain variable region comprising an amino acid sequence represented by: (ii) a heavy chain variable region comprising an amino acid sequence represented by: and a light chain variable region comprising an amino acid sequence represented by: (iii) a heavy chain variable region comprising an amino acid sequence represented by: and a light chain variable region comprising an amino acid sequence represented by: (iv) a heavy chain variable region comprising an amino acid sequence represented by: and a light chain variable region comprising an amino acid sequence represented by: (v) a heavy chain variable region comprising an amino acid sequence represented by: and a light chain variable region comprising an amino acid sequence represented by: (vi) a heavy chain variable region comprising an amino acid sequence represented by: and a light chain variable region comprising an amino acid sequence represented by: (vii) a heavy chain variable region comprising an amino acid sequence represented by: and a light chain variable region comprising an amino acid sequence represented by: (viii) a heavy chain variable region comprising an amino acid sequence represented by: and a light chain variable region comprising an amino acid sequence represented by: (ix) a heavy chain variable region comprising an amino acid sequence represented by: and a light chain variable region comprising an amino acid sequence represented by: (x) a heavy chain variable region comprising an amino acid sequence represented by: and a light chain variable region comprising an amino acid sequence represented by: (xi) a heavy chain variable region comprising an amino acid sequence represented by: and a light chain variable region comprising an amino acid sequence represented by: (xii) a heavy chain variable region comprising an amino acid sequence represented by: and a light chain variable region comprising an amino acid sequence represented by: (xiii) a heavy chain variable region comprising an amino acid sequence represented by: and a light chain variable region comprising an amino acid sequence represented by: (xiv) a heavy chain variable region comprising an amino acid sequence represented by: and a light chain variable region comprising an amino acid sequence represented by: or (xv) a heavy chain variable region comprising an amino acid sequence represented by: and a light chain variable region comprising an amino acid sequence represented by: