Efeito do inibidor farmacológico de mTOR (rapamicina) na resposta de linfócitos T CD8+ gerados pela imunização prime-boost heteróloga

• Ano de defesa: 2019
• Autor(a) principal: Moraschi, Barbara Ferri [UNIFESP]
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de São Paulo (UNIFESP)
• Palavras-chave em Português: CD8+ T Cells; Rapamycin; mTOR; Vaccines; Trypanosoma Cruzi; Linfócitos T CD8+; Rapamicina; Vacinas
• Link de acesso: https://sucupira.capes.gov.br/sucupira/public/consultas/coleta/trabalhoConclusao/viewTrabalhoConclusao.jsf?popup=true&id_trabalho=8039189; https://repositorio.unifesp.br/handle/11600/59354

Vaccination protocol known as heterologous prime-boost is a powerful strategy to elicit effector CD8+ T cells against the parasite Trypanosoma cruzi. It consists in the use of plasmid DNA, followed by a deficient recombinant human adenovirus type 5, both carrying the ASP-2 gene of T. cruzi. Published experimental viral infections, suggested that the inhibition of mTOR, a kinase involved in differentiation, metabolism, migration, and cell death mechanisms, enhances memory CD8+ T population. However, this method to promote a higher memory response in protozoan infection/immunization is not described. Thus, our aim was to analyze the role of rapamycin, the pharmacological inhibitor of mTOR, in immunization-induced CD8+ T response against T. cruzi. For this purpose, C57BL/6, A/Sn, or CD4+ knockout mice were immunized and treated daily with rapamycin during 35 days the evaluation of CD8+ T cell responses by immunophenotyping, intracellular staining, ELISPOT assay and in vivo cytotoxicity. Our results showed that rapamycin-based treatment enhanced the frequency of specific CD8+ T cells and the percentage of the polyfunctional population, which degranulates and secretes both IFN- and TNF, when compared to the immunized group. This Increasing was also observed 95 days after the first dose even in mice immunized with ten-fold lower doses of plasmid/adenovirus. Moreover, mice susceptible to experimental infection by T. cruzi immunized with reduced immunization doses, treated with rapamycin, and infected with trypomastigotes showed a survival rate of 100% whereas the immunized-group rate varied to 42%. Therefore, we sought to identify which CD8+ T cell mechanisms were being modulated by the inhibition of mTOR. It was seen that the in vivo proliferation was higher in the group treated with rapamycin, and CD8+ T effector and memory cells generated by immunization and treatment had a more energetic metabolic profile, which is closely related to function and differentiation of T cells. Taken together, our data provides a new approach to vaccines development against intracellular parasites, since rapamycin has an adjuvant effect on CD8+ T response through modulation of mTOR activity.