A chemical conjugate of anti-CD16 and anti-CD33 monoclonal antibodies was able to redirect cytotoxicity of resting or activated NK cells, as well as peripheral blood lymphocytes toward AML leukemic blasts, with maximum cytotoxicity requiring 10 ng/ml concentrations of antibody.23 Nevertheless, chemical conjugates generally yield a heterogeneous mixture of cross-linked products, of which only a subset has the desired target specificity. Here, CD33 is linked to acute myeloid leukemia.