A Human Mononuclear Leukocyte Chemotactic Factor: Characterization, Specificity and Kinetics of Production by Homologous Leukocytes

Abstract

Leukocytes from peripheral human blood when stimulated in vitro with a specific antigen or a nonspecific mitogen produced a soluble factor which was chemotactic for homologous monocytes. The production of this lymphokine proved to be a sensitive correlate of delayed hypersensitivity. A temporal dissociation between both PHA and PPD-induced lymphocyte proliferation and monocyte chemotactic factor production was clearly established. This factor in non-plasma supplemented cultures was present after 20 to 24 hr of incubation; with minimal amounts of added plasma, a shift to earlier production was noted. Glass bead column purified lymphocytes, stimulated with PHA, produced significant amounts of monocyte chemotactic activity. The chemotactic factor was heat stable, nondialyzable, remained active if lyophilized, and had a molecular weight of approximately 12,500. In addition, this material was antigenically distinct from human C3 and C5, precursors of two chemotactic polypeptides derived from complement.