Genetic control of immunity to Trichinella spiralis in mice. Response of rapid- and slow-responder strains to immunization with parasite antigens.

Slow-responder C57BL/10 (B10) mice responded poorly to immunization with muscle larval antigen of Trichinella spiralis showing no accelerated loss of worms from a subsequent challenge infection. In contrast, rapid-responder NIH mice and (B10 X NIH) F1 mice developed high levels of immunity after immunization. Lymphocyte proliferation studies showed that immunized B10 mice did respond to in vitro restimulation with antigen, though less well than NIH mice. Failure of B10 mice to respond to immunization did not therefore reflect a failure to recognize larval antigen, a view confirmed by the fact that immunization was achieved using abbreviated enteral infections and, to a smaller extent, by parenterally administered muscle larvae.