Human phagocytic cells as oxygen metabolite scavengers.

Human neutrophils or monocytes decreased hydrogen peroxide (H2O2) concentrations in vitro. Neutrophils or monocytes decreased H2O2 concentrations as well as human erythrocytes. Treatment with aminotriazole or azide decreased both phagocyte and erythrocyte catalase activity and the ability of each cell to decrease H2O2 concentrations in vitro. Prestimulation of phagocytic cells with phorbol myristate acetate (PMA) or opsonized zymosan decreased neither their catalase activity nor their ability to decrease H2O2 concentrations. The results suggest that unstimulated or stimulated phagocytic cells can scavenge H2O2 and may potentially decrease H2O2-mediated tissue injury. The H2O2 scavenging potential of phagocytic cells is due at least partially to their catalase activity.