Leukemia-associated antigens detected by heterologous antisera

An antiserum was produced by immunization of rabbits with the membrane fraction of a lymphoblastoid cell line, RPMI 4265. This antiserum reacted against leukemia-associated antigens on immature blast cells of 24 patients with acute leukemia (13 myeloblastic, 11 lymphoblastic). No reactivity was observed against morphologically normal blood mononuclear cells from patients in remission, cells from normal control subjects and patients with unrelated disorders, phytohemagglutinin-induced lymphoblasts, or normal bone marrow cells. Reactivity against leukemia cells was not reduced by absorption with fetal tissues. These findings were consistent with the presence of tumor-associated antigens on leukemia cells. The antigens were detectable neither during hematologic remission nor on cells from patients with unrelated diseases.