Involvement of the Th1 subset of CD4+ T cells in acquired immunity to mouse infection with Trypanosoma equiperdum.
Heat- or merthiolate-inactivated Trypanosoma equiperdum was administered to recipient mice that were subsequently challenged with viable inocula of the same stabilate. Only mice inoculated with merthiolate-killed parasites were completely protected from a challenge inoculum of 10(3) trypanosomes, an effect that was abolished by prior immunosuppression of mice. Immune sera from protected animals contained high levels of interferon (IFN)-gamma and specific IgG2a antibodies. Spleen cells from these mice produced high amounts of interleukin (IL)-2 and IFN-gamma in vitro in response to specific antigen or concanavalin A, whereas splenocytes from mice receiving heat-killed parasites produced high amounts of IL-6. In contrast, the production of tumor necrosis factor (TNF)-alpha and colony-stimulating activity (CSA) was not significantly different in mice receiving either killed parasite preparation. The protection in immunized mice was associated with the detection of strong delayed-type hypersensitivity (DTH) to T. equiperdum antigens, an effect that could be adoptively transferred onto naive recipients by specifically immune CD4+ lymphocytes. These results suggest that the development of protective immunity in mice to T. equiperdum by our immunization protocol may involve the activity of helper/DTH T cells, particularly those of the Th1 subset.
Department of Experimental Medicine and Biochemical Sciences, University of Perugia, Italy.
S
S
Perito
A
A
Calabresi
L
L
Romani
P
P
Puccetti
F
F
Bistoni
D000818:Animals; D000913:Antibodies, Protozoan / Q000096:biosynthesis; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology*; D016207:Cytokines / Q000096:biosynthesis; D005260:Female; D007110:Immunity, Active; D008213:Lymphocyte Activation; D008297:Male; D051379:Mice; D013154:Spleen / Q000276:immunology; D016176:T-Lymphocyte Subsets / Q000276:immunology*; D006377:T-Lymphocytes, Helper-Inducer / Q000276:immunology*; D014345:Trypanosoma / Q000276:immunology; D014352:Trypanosomiasis / Q000276:immunology*; D014611:Vaccination
D000913:Antibodies, Protozoan; D016207:Cytokines