Differences in the regulation of humoral responses between mice infected with Trypanosoma cruzi and mice administered T. cruzi-induced suppressor substance.
In the present study, the effects of Trypanosoma cruzi and the T. cruzi-induced serum suppressor substance (SSS) on antibody responses were compared. Although infection with T. cruzi led to an alteration in T cell helper activity and a reduced specific B cell precursor frequency, SSS did not have a similar effect on either of these cell populations. The characteristics of the altered T cell helper activity was further investigated, and it was found that helper activity appeared earlier in infected mice than in normal or SSS-suppressed mice, and less antigen was required for optimal elicitation of T helper cells in infected mice. The potency of T cell helper activity also was shown to differ, and in the order T. cruzi-infected  6E normal  6E SSS-suppressed mice. It was found that spleen cells from T. cruzi-infected mice elaborated more potent specific helper factors than spleen cells from normal or SSS-suppressed mice, but did not produce a detectable nonspecific helper factor in vitro. Finally, the addition of B cells from low-dose primed, T. cruzi-infected mice to cultures of normal spleen cells resulted in subnormal responses to the priming antigen (sheep erythrocytes) but not to another unrelated antigen (trinitrophenyl-haptenated Brucella abortus), whereas similarly sensitized B cells from normal or SSS-suppressed mice caused no such effect.
D000818:Animals; D000917:Antibody Formation; D001402:B-Lymphocytes / Q000276:immunology; D002478:Cells, Cultured; D014355:Chagas Disease / Q000276:immunology*; D004912:Erythrocytes / Q000276:immunology; D005260:Female; D007166:Immunosuppressive Agents / Q000008:administration & dosage*; D008211:Lymphocyte Cooperation; D051379:Mice; D008810:Mice, Inbred C57BL; D012756:Sheep; D013601:T-Lymphocytes / Q000276:immunology; D014349:Trypanosoma cruzi
D007166:Immunosuppressive Agents