IDENTIFICATION OF SCHISTOSOMA-MANSONI ANTIGENS RECOGNIZED BY T-CELLS OF C57B1 6 MICE IMMUNIZED WITH GAMMA-IRRADIATED CERCARIAE/

Immunization of C57B1/6 mice with gamma-irradiated Schistosoma mansoni cercariae induces highly significant protection against subsequent ch allenge with unattenuated living cercariae. The antigens that evoke T cell-mediated immunity in this model are vaccine antigen candidates si nce T lymphocytes mediate antibody-independent immune responses and co ntrol the production of most antibodies. To identify these antigens, s pleen cells of mice immunized twice with gamma-irradiated cercariae we re tested for proliferative responsiveness and production of interleuk ins (II) and interferon-gamma (IFN-gamma) following incubation with se parated soluble schistosomular (SSA) and adult worm (SAWA) antigens in T cell western assays. Data obtained at 3, 4, 5, and 6 wk post-second ary immunization in 2 experiments indicated that SSA and SAWA bands of 62-60, 50, and 45 kDa reproducibly elicited T cell proliferation and production of Il-2, Il-4, and IFN-gamma by spleen cells from immunized , but not unimmunized, mice. Bands of 72-68, 29.5, and 28 kDa elicited proliferation and production of Il-2 and Il-4, but not IFN-gamma. Ban ds of 35-33 and 24 kDa induced either proliferation or Il production a t some intervals.