Neutrophil-mediated cellular cytotoxicity induced by zymosan-activated serum

Human neutrophils, incubated in the presence of zymosan-activated serum (ZAS), were able to damage ox red blood cells (ORBC) as assessed by a 4-hr ⁵¹Cr-release assay. Cells from a patient with chronic granulomatous disease were incapable of mediating ZAS-induced cytolysis. Cytotoxicity by normal neutrophils was prevented by N-ethyl-maleimide as well as by catalase, but heat-inactivated catalase and superoxide dismutase were completely ineffective. Heme enzyme inhibitors, azide and cyanide, only partially reduced the target cell lysis. The results indicate the involvement of products of the oxidative metabolism, mainly hydrogen peroxide, as cytolytic mediators. These mediators released by neutrophils may contribute to the tissue injury occurring during inflammation.