title: Failure of nude (athymic) rats to become resistant to reinfection with the intestinal coccidian parasite Eimeria nieschulzi or the nematode Nippostrongylus brasiliensis.
abstract: The course of each of three successive infections with Eimeria nieschulzi in nude (athymic) rats was the same as the primary infection in nu/+ animals, with the production of more oocysts. This indicates that resistance to reinfection with this parasite is mediated by T lymphocytes but that these cells do not control the duration of the life cycle, since oocyst production was not prolonged in the nu/nu rats. After the three infections with E. nieschulzi, the rats were exposed twice to the intestinal nematode Nippostrongylus brasiliensis, and the nu/nu were completely susceptible even to the second infection. Egg production by both infections in the nu/nu animals was similar and continued at a high plateau level for 28 days before falling to a low level. It appears that the strain of N. brasiliensis used in this study is unable to sustain high egg production for more than 4 weeks in T cell deficient rats.
mesh_terms: D000818:Animals; D003048:Coccidiosis / Q000276:immunology*; D004539:Eimeria / Q000276:immunology; D007411:Intestinal Diseases, Parasitic / Q000276:immunology*; D008297:Male; D009349:Nematode Infections / Q000276:immunology*; D009559:Nippostrongylus / Q000276:immunology; D051381:Rats; D013950:Thymus Gland / Q000002:abnormalities