Oral and parenteral vaccination against Trichinella spiralis infections in high- and low-responder mice.

Vaccination by different routes and with different adjuvants is known to influence profiles of immune responses and may be used to overcome genetically determined low-responsiveness to infection. A mouse model of infection with the intestinal nematode Trichinella spiralis was used to investigate the effect of mode of vaccination upon immune responsiveness and worm expulsion phenotype in high- (NIH) and low- (C57 BL/10) responder strains of mice. Muscle larval homogenate antigen was given subcutaneously in Freund's complete adjuvant (FCA) to induce a systemic immune response or with cholera toxin (CT) orally to stimulate mucosal immunity. Both approaches significantly protected NIH mice. Vaccination with FCA was correlated with elevated serum IgG after infection, whereas oral CT-vaccination resulted in increased levels of intestinal IgA. Neither type of vaccination successfully protected the low-responder C57 BL/10 strain and there were no effects on the low antibody levels that infection induced in this strain.