ACQUIRED-RESISTANCE TO SCHISTOSOMA-JAPONICUM IN IGE-DEFICIENT SJA 9 MICE IMMUNIZED WITH IRRADIATED CERCARIAE/

Participation of IgE in protective immunity against Schistosoma japoni cum was examined by comparing congenital IgE-deficient SJA/9 and IgE-p roducing SJL/J mice. Mice immunized with 100 irradiated cercariae 7 we eks previously were infected with 50 live cercariae. In SJL/J mice at 40 days after infection, a 3- to 4-fold increase of total IgE levels a nd anti-S. japonicum egg IgE antibody production were observed with no significant difference between immunized and nonimmunized mice. IgE w as not detected in SJA/9 mice throughout the experiments. Protective i mmunity evaluated by recovery of adult worms was found in SJA/9 mice a nd was comparable to that of SJL/J mice. These results suggest that ac quired immunity in mice, with irradiated cercariae of S. japonicum was not dependent on IgE in these strains of mice.