Early immune response induced by different Trypanosoma cruzi infective stages

BRENDA GUTIERREZ; ESTELA LAMEL; MARCEL RAMIREZ; STELLA M GONZALEZ CAPPA; CAROLINA PONCINI

Mar del Plata

Congreso; Reunión Conjunta Anual; 2018

Trypanosoma cruzi is an intracellular protozoan parasite that affects millions of people in Latin America. Infection commonly occurs by vectorial transmission via skin and/or mucous membranes. Immunologic events occurring immediately after the parasite entrance are poorly studied. Skin constitutes a complex network and includes several population of antigen presenting cells (APCs). The phenotype, localization and functional properties define cellular identity. Trypanosoma cruzi infective stages would condition the repertoire of cells recruited into the site of infection.In the intradermic model, blood and in vitro cultured metacyclic trypomastigotes (bTp and mTp, respectively) not only displayed differences in cell recruitment at the site of infection, but also the populations of APCs and their activation in draining lymph nodes and spleen. Animals inoculated with mTp exhibited 100% of survival with no parasite detection in blood, in contrast with the ones injected with bTp that displayed 80% of mortality and high parasitemia. Infection after mTp inoculation was confirmed by qPCR, not only at the site of infection but also in spleen. Animals infected with mTp and challenged with bTp 15 days later showed APCs with enhanced activation in secondary lymphoid organs compared to controls injected with bTp or not infected mice. These animals also displayed a less number of amastigote nests in cardiac tissue than bTp infected ones. All the results suggest that bTp and mTp differently infect mice. In addition, both stages induce an unequal immune response since the very beginning of the infection.