C3a-Induced Lysosomal Enzyme Secretion from Human Neutrophils

C3a-induced lysosomal enzyme secretion from human peripheral neutrophils in a noncytolytic, dose-dependent (10–100 μg/ml) process. Release of both primary and secondary granule constituents occurred when neutrophils were exposed to C3a plus cytochalasin B, however, C3a alone induced limited release of lysozyme. A competitive antagonist of the formyl-peptide receptor on neutrophils, t boc (phe-leu)₂-phe, did not block the release induced by C3a. Arachidonic acid antagonists, nordihydroguaiaretic acid and quercetin caused dose-dependent inhibition of release induced by C3a plus cytochalasin B, however, lysozyme release induced by C3a in the absence of cytochalasin B was minimally affected. Indomethacin at high concentration (> 10^––⁵<i>M</i>) had similar inhibitory effects.