Characterization and distribution of a 24,000-molecular weight antigen defined by a monoclonal antibody (DU-ALL-1) elicited to common acute lymphoblastic leukemia (cALL) cells.

A monoclonal antibody (DU-ALL-1) was generated to common acute lymphoblastic leukemia (cALL) cells by microcytotoxicity and indirect immunofluorescence, DU-ALL-1 reacted only with cALL cell lines and not with the other hematopoietic cell lines tested. Peripheral blood lymphocytes, monocytes, granulocytes and mitogen-activated lymphocytes did not react significantly with this antibody. However, platelets (100%) and normal bone marrow cells (8.5%) reacted with DU-ALL-1. Microcytotoxicity testing of human leukemia cells showed that DU-ALL-1 reacted with cells from a majority of null and pre-B ALL patients (63/77) and with cells from some patients with acute myeloblastic leukemia (4/7) and T-ALL (4/20). DU-ALL-1 was generally non-reactive with cells from patients with B-cell leukemias (2/16) and chronic myelogenous leukemia in blast crisis (0/4). By an indirect immunoperoxidase technique, DU-ALL-1 reacted with a variety of non-hematopoietic tissues, including smooth and cardiac muscle and epithelia from several organs. The DU-ALL-1 antigen had an apparent mol. wt of 24,000 and did not bind to lectins or label with [3H]glucosamine. Thus, DU-ALL-1 defines a 24,000-mol. wt protein which is absent from most peripheral blood mononuclear cells, is expressed on normal platelets and several non-hematopoietic tissues, and may be a useful for subclassifying leukemias.