A surface antigen marker for human monocytes.

Antisera have been raised in rabbits aginst human peritoneal macrophages. After absorption with tonsil cells the sera reacted, by direct and indirect immunfluorescence, with phagocytic mononuclear cells from a variety of tissues and, in addition, stained a small population of nonphagocytic non-T, non-B mononuclear cells present in blood, spleen, and marrow but absent or very rare in tonsil and thymus. The antisera may define a human monocyte-macrophage cell surface differentiation antigen (HuMA) and can be used to deplete or enrich reactive cell population.