In vitro interactions between murine neutrophils and Eimeria falciformis sporozoites

The in vitro interactions between elicited mouse peritoneal neutrophils, antibodies and newly excysted sporozoites of Eimeria falciformis resulted in lysis of the parasite. This lysis required the presence of a heat-labile component of normal mouse serum, and was antibody- and cell-concentration-dependent. Under optimal conditions (serum dilution = 1/192, effector cell/sporozoite = 10/1) this lysis, which began after incubation at 37 degrees C for 4 h, was nearly complete after 18 h. It began by opsonization of the sporozoites by antibodies and complement. Inhibition studies performed with inhibitors of neutrophil function did not enable us to determine the mechanism of this extracellular lysis (oxidative respiratory burst or enzyme release), since only metal chelators, lysosomotropic reagents and compounds known to interfere with adenylate cyclase activity were truly inhibitory.