Studies on immune responses to parasite antigens in mice. III. Nippostrongylus brasiliensis infections in hypothymic nu/nu mice.

Normal mice of several strains reject the nematode worm Nippostronglyus brasiliensis from the intestine within 14 days (and most often within 10 days) of injection of high numbers of infective third stage larvae (L3). Previously-infected mice are markedly resistant to a second infection. Hypothymic, nu/nu ('nude') mice continue to harbor worms long after intact mice have rejected the worm burden and an inoculum of T cells at the time of, or several days after L3 injection, leads to worm elimination within 14 days in nu/nu mice. As yet no evidence is available to indicate whether or not T cells with specificity for parasite antigens are required in a reconstitutive inoculum in nu/nu mice. Pretreatment of normal mice with cyclophosphamide, at doses reported to lead to temporary B cell hypofunction, does not result in delayed rejection of worms but the participation of B cell products (antibodies) cannot be discounted on the basis of this result. The nu/nu mouse - N. brasiliensis system will be useful in the search for, and characterization of, parasite antigens which gain access to the lymphoid organs and circulation of parasitized mice and in the analysis of T cell subtypes (both functional and surface Thy and Ly alloantigenic subtypes) involved in worm elimination.