Evaluation of the cellular and humoral response in mice inoculated with irradiated tachyzoites of Toxoplasma gondii

Abstract

Objectives: Evaluate the cellular, humoral immune response and the protection against oral challenge in mice, induced by 255 Gy T. gondii irradiated tachyzoites in a source of 60 Co γ-rays. Material and Methods:T. gondii tachyzoites were irradiated with 255 Gy, maintained in nitrogen and freezer. C57Bl/6j mice were immunized with irradiated tachyzoites (3 doses). The humoral and cellular response in immunized mice was analyzed. The immunized mice with 255 Gy irradiated tachyzoites (3 doses) were challenged, by oral route, with ME-49 T. gondii strain, mortality and quantification of cysts number was analyzed. Results:The mice immunized with irradiated tachyzoites presents right levels of IgG antibody specifics, which recognized T. gondii proteins. The mice spleen cells presents lymphoproliferative response and cytokine profiles similar to those produced by chronic infection. The mice immunized with irradiated tachyzoites displayed minimal cerebral pathology and low cysts numbers after oral challenged with ME-49 strain. Conclusions:The 255 Gy γ-rays irradiated T. gondii tachyzoites induce immune response in mice, similar chronic infection, with partial protection after challenge with ME-49 strain, presenting decrease of the cerebral pathology and cysts numbers.Roberto Mitsuyoshi Hiramoto hiramoto@usp.br