Balanced cytokine-producing pattern in mice immunized with an avirulent Trypanosoma cruzi.

We have previously demonstrated that inoculation of BALB/c mice with trypomastigotes of CL-14, an avirulent Trypanosoma cruzi clone, prevents the development of parasitemia and mortality after challenge with virulent CL strain. In this report, we investigated the cytokine and antibody profiles induced by inoculation with CL-14 clone. Groups of mice were inoculated with trypomastigotes of CL-14 clone and challenged with infective CL strain. Challenged CL-14-inoculated mice had lower levels of IFN-gamma and higher production of IgG1 antibodies as compared to CL strain-infected mice. Previous inoculation with CL-14 clone partially prevented the suppression of IL-2 production caused by CL strain infection. No significant differences were found regarding IL-4 production by splenocytes from CL-14-inoculated or control groups after challenge with CL-strain. Our results show that protection against acute T. cruzi infection induced by CL-14 inoculation correlates with a balanced T1/T2 cytokine production, a profile likely to be beneficial for the host