[Monoclonal antibodies to the antigen of myeloid cells].

ICO-G-2 hybridoma clone was obtained after fusion of spleen cells from BALB/c mice immunized with cells from a patient with acute myelomonoblastic leukemia (AMML) and P3 X 63 Ag8.653 cells, using 50% polyethyleneglycol, molecular weight 1500 KD. The antigen with a molecular weight of 100 KD was present only on polymorphonuclear neutrophils and eosinophils of the peripheral blood. The antigen expression was also found on the majority of myeloid precursors and some nuclear erythroid cells. CFU-GM did not express the antigen. Monoclonal antibodies ICO-G-2 reacted with blast cells of some patients with AML, AMML and CML. The antibodies did not react with cells from patients with AMonL, CMonL, ALL, CLL and LSA. Such pattern of reactivity makes these monoclonal antibodies useful for the differential diagnosis of acute nonlymphocytic leukemias and CML in blast crisis.