Thrombin enhances opsonized zymosan-induced chemiluminescence of neutrophils

Abstract

We examined the effects of α-thrombin (the native enzyme) on neutrophil activation as assessed by the measurement of chemiluminescence. α-Thrombin in physiological concentrations (10 −9 − 10 −8 M) did not induce neutrophil chemiluminescenee. However, when neutrophils were coincubated with opsonized zymosan and α-thrombin, the chemiluminescence response to opsonized zymosan was enhanced in a concentration-dependent manner. The neutrophil chemiluminescence responses to opsonized zymosan and to opsonized zymosan plus α-thrombin were dependent on the generation of oxygen-derived free radicals since the chemiluminescence was inhibited by superoxide dismutase. The results indicate that thrombin per se does not induce neutrophil chemiluminescence. However, thrombin enhances the chemiluminescence response to opsonized zymosan suggesting an interaction between thrombin and complement receptors in inducing neutrophil activation. The chemiluminescence response to thrombin and opsonized zymosan is the result of oxygen-derived free radicals.