Preparation of a monoclonal antibody against human monocyte lineage.

Preparation and characterization of a monoclonal antibody termed M206 directed to a human monocyte lineage are described. The antibody was produced by somatic cell hybridization between BALB/c spleen cells primed with human histiocytic lymphoma cell line U937 and murine myeloma cell line P3U1. The antibody reacted intensely with human peripheral blood monocytes as well as U937 but did not react with peripheral blood T and B cells. Granulocytes were weakly stained with the antibody by indirect immunofluorescence. M206 also reacted intensely with the immature leukemic cells from patients with acute monocytic leukemia but was unreactive with other types of leukemic cells except cells from chronic myelogenous leukemia which showed varied patterns of reactivities. M206 reacted with a single polypeptide chain with a molecular weight of 180,000 on the surface of U937 cells.