A DIFFERENTIATION ANTIGEN EXPRESSED SELECTIVELY BY A PROPORTION OF HUMAN-BLOOD CELLS - DETECTION WITH A MONOCLONAL-ANTIBODY

A monoclonal antibody, FMC 8, was prepared after immunization [of mice] with a cell line of the non-T-non-B type acute lymphoblastic leukemia (ALL). The antigen detected by this antibody consists of a single polypeptide chain with an apparent MW of 24,000 d [daltons]. The antigen is absent from T cells but appears after mitogen stimulation. It is found on the majority of normal circulating B cells but is absent in most chronic lymphocytic leukemias. All cells of the non-T-non-B type express the antigen; T-ALL cells generally do not. Granulocytes, monocytes and platelets react with the antibody, but erythrocytes do not. The wide but selective distribution of the antigen renders FMC 8 potentially useful, together with other monoclonal antibodies, in the delineation of differentiation pathways and in phenotypic analysis of [human] leukemia and lymphoma cells.