Schistosoma japonicum: the modulation of lung granuloma and inhibition of egg maturation in mice by human sera.

Human sera taken from patients with chronic schistosomiasis japonica have been demonstrated to have two effects on mice. Sera from those patients reduced the size of granuloma in mice sensitised for accelerated granuloma formation to eggs entrapped in the lungs of mice injected with the sera shortly before and at day 2 after intravenous egg challenge. The sera with this effect on the mouse lung granuloma models caused large segmented precipitates in the optimised circumoval precipitin test (COPT). Such sera also reduced the rate at which eggs matured in the liver and intestines of mice infected with S. japonicum. The results strongly support our postulate that a major cause of granuloma modulation in cases of chronic schistosomiasis japonica is antiembryonation immunity and that mice provide useful models for the analysis of our postulate. Identification of egg antigens responsible for the anti-embryonation effect should facilitate progress towards the development of a vaccine against granulomatous disease.