Citocinas, citoesqueleto de actina e a P21 de Trypanosoma cruzi na multiplicação intracelular do parasito in vitro

Abstract

Chagas disease, caused by the protozoan Trypanosoma cruzi, affects about 8 million people worldwide. The disease is manifested in two phases, acute, characterized by high parasitaemia, and chronic by control of infection by the host. An adequate immune response is required to control infection. The response profile to infection by T. cruzi is the T helper type 1 (Th1). In recent studies, it was shown that the cytokines IL-3, IL-7 and IL-10 are highly expressed during the chronic phase of experimental infection by T. cruzi. The IFN-γ and IL-10 cytokines have been extensively studied to infection by T. cruzi, and IFN-γ plays a fundamental role in controlling parasitemia in the acute phase. The rP21 protein based on the P21 of T. cruzi induces nonspecific phagocytosis, polymerize actin cytoskeleton and seems to be matter in the passage to the chronic phase of the disease. Thus, in this study we analyzed the role of IFN-γ, IL-3, IL-7, IL-10 cytokines and the rP21 protein on in vitro infection by T. cruzi, and analyzed the role of these cytocines in the polymerization of actin. It was observed on peritoneal macrophages and myoblasts C2C12, that the cytokines IFN-γ, IL-7 and rP21 protein, induce the polymerization of actin cytoskeleton. Moreover, in macrophages and myoblasts infected with G and Y strain was seen differential effect of cytokines and rP21 in the parasite multiplication. However, in all analyzed groups IFN-γ and rP21 decreased parasite multiplication. This effect may be due to the induction of actin polymerization, along with induction of nitric oxide (NO) and reactive oxygen species (ROS) for the groups treated with IFN-γ. Meanwhile, the observed effect of rP21 seems to be linked by only with the actin cytoskeleton where the polymerization thereof, act in forming a mechanical barrier for parasite multiplication. Therefore, it is important to investigate the potential role of the actin cytoskeleton during intracellular multiplication of the parasite and its interaction with the host\'s immune response once an understanding of the modulation of such properties, would provide a basis for better understanding of the biology of the parasite.