The role of superoxide anion generation in antibody-dependent polymorphonuclear leukocyte-mediated cytotoxicity

Human polymorphonuclear leukocytes (PMNs) can act as killer cells in an antibody-dependent cellular cytotoxicity (ADCC) system. Cytolysis is rapid and detectable at low effector/target cell ratios. PMNs from a patient affected by chronic granulomatous disease (CGD) exhibit an absolute defect in ADCC. In order to investigate the role of the toxic oxygen derivatives (H2O2 and superoxide anions) lacking in CGD, experiments in presence of specific inhibitors were carried out. Superoxide dismutase, an O-2 scavenger, displayed a significant inhibition activity in a dose dependent way. On the other hand neither catalase, which degrades H2O2, nor sodium azide, a myeloperoxidae inhibitor, affect the cytotoxic activity. Our results suggest that the importance of the intact oxidative metabolism in PMN-mediated ADCC against chicken red blood cells could be referred to the correlated production of O-2 anions.