Schistosoma mansoni: in vitro and in vivo killing of antibody-coated schistosomula.

Mechanically transformed schistosomula of Schistosoma mansoni exposed to mouse, rat or human inactivated immune sera (coated schistosomula) and then injected intravenously into CBA mice were recovered from their lungs in smaller numbers than were schistosomula exposed to normal sera, immune sera absorbed with S. mansoni tegument, or sera from mice bearing unisexual cercarial infections and displaying moderate titers of lethal antibodies. The reduction of the number of coated schistosomula recovered from the lungs, as well as the lethal effect in vitro, were mediated by 7S fraction of the immune sera. Decomplementation (by Cobra Venom Factor) or irradiation (650 R, 1, 3, and 5 days before injection) of recipient mice, increased the number of coated schistosomula recovered from their lungs.