THE ENHANCING EFFECT OF CYTOCHALASIN A ON CONCANAVALIN A-INDUCED SUPEROXIDE ANION RELEASE FROM POLYMORPHONUCLEAR LEUKOCYTES

Superoxide anion release from polymorphonuclear leukocytes stimulated by concanavalin A was markedly enhanced by the simultaneous addition of cytochalasin A at concentrations of 2×10-8 to 4×10-7M. These concentrations of cytochalasin A did not affect the phagocytosis of diisodecyl phthalate emulsion. These concentrations were far lower than those of cytochalasins B, C, D and E that also enhanced concanavalin A-induced superoxide anion release. Superoxide anion release stimulated by concanavalin A and cytochalasin A required the binding of concanavalin A on the cell membrane, and was dependent on the existence of extracellular Ca2+. The enhancement by cytochalasin A was reversible. It is suggested that cytochalasin A acts not only as a sulfhydryl reagent as reported previously, but also has actions resembling the other cytochalasins.