Secretion profile of the TcTASV-C proteins in different Trypanoosma cruzi strains.

CAEIRO, L; SANCHEZ DO; TEKIEL, V

Córdoba

Congreso; 52th Annual Meeting Sociedad Argentina de Investigación en Bioquímica y Biología Molecular (SAIB); 2016

Sociedad Argentina de Investigación en Bioquímica y Biología Molecular (SAIB)

TcTASV is a T.cruzi -specific protein family preferentially expressed in trypomastigotes, the extracellular bloodstream stage of the parasite. In particular, the TcTASV-C subfamily is located at the parasite surface. Mice vaccinated with TcTASV-C are partially protected after a T. cruzi lethal challenge. In trypomastigotes of the reference strain (CL Brener; TcVI hybrid lineage) TcTASV-C is secreted into small extracellular vesicles (EVs). Other researchers showed that EVs from different T. cruzi strains trigger differential immune responses in the host. Considering that TcTASV-C could be a virulence factor, we here analyse the secretion profile of TcTASV-C in different strains, by ultracentrifugation and western blot. We found that in the highly virulent RA strain (TcVI) TcTASV-C is secreted in similar proportions in small and large EVs. On the other hand, in the low-virulent Sylvio strain (TcI) TcTASV-C is secreted both in the large EVs and the vesicle-free fractions. We also evaluated the reactivity of sera from T. cruzi infected hosts against EVs proteins. None of the three species assayed (human, rabbit and mouse) reacted against vesicles, suggesting that secretion of T. cruzi antigens into EVs could be a mechanism of immune evasion. In contrast, TcTASV-C vaccinated mice that survived the T. cruzi challenge were able to efficiently recognize EV antigens.