DEMONSTRATION OF A HOMOLOGOUS ANAPHYLACTIC ANTIBODY IN RABBITS INFECTED WITH SCHISTOSOMA MANSONI

Groups of rabbits were exposed to 1000, 5000, or 25,000 S. mansoni cercariae. Flocculating antibodies were detected by the use of somatic antigens from eggs and cercariae, and by metabolic antigens from adult worms. Flocculating antibodies appeared in all the animals by the 3rd week and persisted throughout the experiment. Highest titers were obtained with the adult metabolic antigen. Nine of 11 rabbits developed an antibody which produced passive cutaneous anaphylaxis in normal rabbits challenged with cercarial antigen. This antibody appeared 7-12 weeks following infection. It remained elevated for 3-6 weeks, often in high titers, and then either could no longer be demonstrated, or was detected at very low titers. Reinfection with 5000 cercariae at 36 weeks elicited an abrupt return of anaphylactic antibodies in 1/2 of the animals. The anaphylactic antibody was inactivated by heating at 56[degree]C and by mercaptoethanol. No obvious correlation was observed between antibodies detected by slide flocculation tests and those detected by passive cutaneous anaphylaxis.