Protection of rats against nippostrongylus brasiliensis with worm antigens by oral administration.

Different types of antigens collected from adult Nippostrongylus brasiliensis were used to vaccinate rats against this parasite: somatic worm homogenate, secretory antigens and whole fixed worms. After challenge infection there was a significant reduction of worm number in immunized rats. However, vaccination with secretory antigens only induced a high level of immunity, indicating that protective antigens were probably worm metabolites.