Nippostrongylus brasiliensis: observations on the comparative immunogenicity of adult worms from primary and immune-adapted infections

Abstract

A comparison was made of the immunogenicity of normal worms, derived from a primary infection, and immune-adapted worms, derived from a trickle infection, after surgical transfer into previously uninfected rats. Exposure to 300 normal worms for 2 days was sufficient to induce resistance to challenge infection 3 weeks later in four of eight rats. The immune-adapted worms were, however, significantly less immunogenic, only one rat in ten developing resistance to challenge after 21 days exposure to 300 worms. These results offer further evidence that the protective antigens produced by normal worms are in some way altered in adapted worms, so that adapted worms have a reduced immunogenicity.