Imunoreatividade dos cistos cerebrais de t. Gondii, frente a diferentes antisoros, em camundongos C57BL/6 que sofreram depleção de células T CD4+ e/ou T CD8+ ou que foram neutralizados de IFN-γ ou TNF-α

Abstract

In immunocompromised states, T. gondii produces a severe disease, possibly due to the reactivation of chronic infection, usually presenting as encephalitis. The present study shows the results of experiments carried out on brain cysts of C57BL / 6 mice chronically infected with the T. gondii ME-49 strain. The specific antigens of the tachyzoite P30 and P22, antigens of the strains PLK, PTgB, CEP, PJA and RH, antigen of the oocyst stage, as well as the heat shock protein of 70 kDa (Hsp 70) in the brain cysts, through the immunocytoquinuca reaction. The animals were depleted of CD4 + and / or T CD8 + T cells or IFN-y or T N F α neutralized and the bradyzoite to tachyzoite stage interconversion was evaluated by the expression of P30 and P22 antigens. The antigenic sharing between the different strains of T. gondii mentioned above was also evaluated, with the ME-49 strain, the sharing of the oocyst stage antigen with the cystic parasites and the expression of the Hsp 70 protein. 3 animals per group were always used and several cysts in each group were analyzed. The intensity of labeling for each antigen and size of the cysts were analyzed using the UTHSCSA Image Tool program, developed at the University of Texas Health Sciences Center, San Antonio, Texas. The number of brain cysts in each immunosuppression condition was also evaluated. Animals treated with anti-CD4 and / or anti-CD8 monoclonal antibody showed a greater number of brain cysts than animals treated with control monoclonal antibody. This effect was also observed in animals treated with monoclonal anti-IFN-γ or anti-TNF α, as well as a decrease in the size of the cysts. It was observed that the depletion of T CD4 'and / or T CD8 * cells, or in the treatment of fFN-y or TNF-ct promoted the highest expression of tachyzoite antigens, with stage interconversion occurring, with the effect neutralization of ÍFN-y or TNF-a was more severe. During this interconversion period, the parasites express the heat shock protein, Hsp70, which is probably involved in the adaptation of the parasite during this event. Enlisted parasites also present antigens with the ME-49 strain, when detected in the parasitic cystic structures, present in cuts of brain tissue from infected animals.