Allergens of Schistosoma mansoni. I. Comparison of the IgE response in human and experimental infections towards characterized allergens from adult worm products.

The reaction of adult worm products of Schistosoma mansoni with IgE antibodies in infected human and Fischer rat sera has been studied using the Prausnitz-Küstner test and the radioallergosorbent test. Incubation of worms in water released most of the soluble material reacting with both rat and human sera in the radioallergosorbent test. Sera from infected Fischer rats recognized a fraction with pI 4.9-5.2 separated by preparative isoelectric focusing throughout the time course of infection, whereas human sera reacted with material focusing between pI 4.4 and 6.0. A peak of allergenic activity with an apparent molecular weight between 70,000 and 150,000 was obtained by gel filtration. Human bilharzian sera also reacted with material in the molecular weight range 12,000-25,000. Allergenic material bound specifically to concanavalin A-Sepharose, Lens culinaris agglutinin-Ultrogel, and wheat germ agglutinin-Ultrogel, but substantial allergenic activity was also present in unbound fractions.