Potentiation of rat reaginic (IgE) antibody by Nippostrongylus brasiliensis infection: effect of modification of life cycle of the parasite in the host.

Experiments were performed to determine the ability of different stages of the nematode N. brasiliensis to potentiate reagin responses. The life cycle of the parasite in the host was restricted on the one hand to the migrating larval phase by the radiation-attenuation of infective larvae or treatment of the host with anthelmintic drugs, and on the other hand to the gut phase by surgical transplantation of adult worms to the small intestine. The facts which emerge are that IgE responses are potentiated by both migrating larvae, and by adult worms confined to the small intestinal lumen. The implications of these findings for other parasitic infections are discussed.