Effects of preintestinal larval antigenic stimuli on the generation of intestinal immunity in Strongyloides ratti infection in rats.

Generation of intestinal immunity by antigenic stimulation with preintestinal, tissue-migrating larvae was investigated in the Strongyloides ratti-rat model. The results of daily fecal egg counts showed that the intestinal immunity against adult worms could be partially generated by priming with preintestinal migrating larvae. A further study demonstrated that this partial reduction of daily fecal egg count was mainly the result of inhibitory effects on the fecundity of the parasitic females, although the expulsion of the parasite from the gut could be advanced by several days. After tertiary immunization with preintestinal larvae, no significant potentiation in the protection was observed when compared with the rats treated by primary immunization alone.