DIFFERENTIAL IMMUNOLOGICAL OUTCOME AFTER INFECTION WITH TRYPANOSOMA CRUZI NATURAL ISOLATES

PAULA G. RAGONE; PATRICIO DIOSQUE; NICOLÁS TOMASINI; LEONARDO ACUÑA; DELFOR A. UNCOS; FEDERICO RAMOS; CECILIA PÉREZ BRANDAN

Salta

Congreso; The LV Annual SAIB Meeting and XIV PABMB Congress; 2019

Sociedad Argentina de Bioquímica y Biología Molecular

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