Comparative superoxide-generating system of granulocytes from blood and peritoneal exudates.

Blood polymorphonuclear leukocytes (PMN), upon interaction with specific chemotactic stimuli, leave the blood stream and migrate to tissues. At such a location, and upon contact with invading microorganisms, they generate superoxide (O2-) as a part of the respiratory burst of phagocytosis. We have compared the O2(-)-generating system of guinea pig peritoneal exudate PMN with that of peripheral blood PMN from the same species or of human origin. The rate of O2- production by casein-induced guinea pig exudate cells in response to a particulate stimulus (opsonized zymosan) was significantly decreased when compared with peripheral blood PMN. Furthermore, the activation time of the O2(-)-generating system was shorter in exudate than in peripheral blood PMN. Important differences in sensitivity to a metabolic inhibitor were found: (i) N-ethylmaleimide increased the activation time of the O2(-)-generating system only in guinea pig exudate cells and not in blood cells; (ii) when N-ethylmaleimide was added after complete activation of the PMN, the O2- production rate was inhibited in guinea pig as well as human blood PMN, but not in guinea pig exudate PMN. We conclude that exudation markedly alters one of the most important antibacterial mechanisms of PMN, the superoxide-generating system.