DIFFERENTIAL IMMUNOLOGICAL OUTCOME AFTER INFECTION WITH Trypanosoma cruzi NATURAL ISOLATES

RAGONE, PG*; DIOSQUE, P; TOMASINI, N; ACUÑA, L; UNCOS, DA; RAMOS, F; PÉREZ BRANDÁN, C

Congreso; Jo int XIV PABMB Congr ess and LV Ann ual SAIB Meeting; 2019

Chagas disease outcome depends on critical interactions between the genetic diversity of the causal agent Trypanosoma cruzi and host factors as the immune system. This idea was elucidated using animal models to understand how immunological processes contribute to controlling parasite levels and promoting tissue inflammation in the chronic phase. In this work we evaluated the immune response associated to the parasite load induced by two natural isolates characterized as DTUs TcVI and TcV, which are the prevalent DTUs in human infections in Argentina. For this purpose, C57BL/6 mice were inoculated with Triatoma infestans -derived parasite forms of two isolated obtained from an endemic area for Chagas disease in Argentina. At different time points, we measured the concentrations of total IgGs and IgG subtypes and the levels of IL-10, IFN-ɣ, and TNF-α. Besides, parasite load in blood and target organs was measured by qPCR. In our results mice infected with isolate TcVI presented a specific antibody response at 30 days post-infection (dpi) with a predominance of the subtype IgG2 and high levels of anti-inflammatory cytokine IL-10 followed by IFN-ɣ, and TNF-α. Whereas mice infected with TcV isolate presented a serological response at 90 dpi without predominance of any IgG subtype in particular and almost an undetectable cytokine response. In spite of this, circulating parasite and different parasite load in blood, heart and skeletal muscle we detected in both experimental groups. In conclusion, we detected marked differences at the immunological level product of the infection by two natural isolates of different DTUs. Isolate TcVI induces, during the acute phase of infection, a robust specific antibody response and cytokine profile that controlled the infection during the chronic phase. While isolate TcV does not seem to induce an early activation of the immune system allowing to establish a subpatent and almost undetectable infection in infected mice.