Requirements for the induction of cross-reactive anti-Trichinella IgE antibodies in mice.

Mice primed with Trichinella spiralis or T. pseudospiralis and reinfected with either the homologous or the heterologous species produced high levels of IgE antibodies that cross-reacted with the non-inducing strain in passive cutaneous anaphylaxis assays. Cross-reactive antibodies were not induced by primary infection. Cross-reactivity persisted for more than 6 months following secondary infection or destruction of encysted larvae with mebendazole. Both the prevention of larvi-position by thiabendazole and the interruption of infection using naphthalophos indicated that the presence of the pre-adult stage alone provided sufficient priming for the induction of detectable levels of cross-reactive IgE by subsequent reinfection. These results suggest the existence of two sets of Trichinella allergens, one comprising species-specific major allergens (MAs) and the other comprising minor allergens (mAs) evoking a cross-reactive IgE response that occurs to a detectable extent only when the response to MAs has reached its ceiling. These findings are relevant to the design of experiments investigating the role played by IgE antibodies in protection against reinfection in rodents.