Using the hybridoma technology, the author produced and applied six monoclonal antibodies (McAb) against human myeloid cells.These McAbs were produced by immunizing BALB/c mice with whole cell suspensions of fresh AML cells or HL-60 cells and were named Zh₅₃, Zh_2-1, Zh₈₀₅, Zh₈₂₆ Zh₈₂₀ and Zh₁₁₄, respectively.Western blotting analysis showed that these McAbs could recognize different antigens with different molecular weights.These antigens expressed themselves on the surface of leukemic cells from most patients with acute myeloid leukemias and some normal human myeloid cells.Five of the six McAbs were capable of fixing rabbit complement and showed strong complement-mediated cytotoxicity to leukemic cell line HL-60 cells with dead cells ranging from 73% to 94%.CFU-GM growth assay showed that the complement-fixing antibodies Zh₅₃, Zh_2-1 and Zh₈₀₅ did not produce any significant inhibition to normal CFU-GM colony growth, but the antibodies Zh₈₂₀ and Zh₁₁₄ revealed their respective inhibition rates of 24% and 20%.