Surface Sulphydryl Groups and Phagocytosis‐Associated Oxidative Metabolic Changes in Human Polymorphonuclear Leucocytes

Abstract

The role of surface sulfhydryl (-SH) groups of human polymorphonuclear leukocytes on phagocytosis and phagocytosis-associated oxidative metabolic changes was studied. p-Chloromercuribenzene sulfonic acid, a surface -SH group inhibitor, had no effect on phagocytosis, superoxide production during phagocytosis, or killing of Staphylococcus aureus by the leukocytes, while it inhibited phagocytosis-associated stimulation of hexose monophosphate pathway activity and H2O2 production. In contrast, N-ethylmaleimide, which inhibited both intracellular and surface -SH groups, inhibited phagocytosis and phagocytosis-associated oxidative metabolic changes. p-Chloromercuribenzene sulfonic acid also inhibited the stimulation of hexose monophosphate pathway activity by exogenous H2O2, suggesting a regulatory role of plasma membrane on the pathway''s activity in human polymorphonuclear leukocytes. Superoxide production was apparently the primary event of oxidative metabolic changes during phagocytosis and played an important role in the killing of S. aureus. The hexose monophosphate pathway probably played a primary role in producing NADPH for H2O2 production from superoxide.