INNATE CD8+ T CELLS: FROM THE THYMUS TO THE SECONDARY LYMPHOID ORGANS (SLO) IN STEADY STATE VERSUS TRYPANOSOMA CRUZI INFECTION

CONSTANZA SAVID FRONTERA; CERBAN F; BAEZ, NATALIA S.; M CECILIA RODRIGUEZ GALAN; VIANO, MARIA ESTEFANIA; MATELLON, M

Congreso; Reunión de la Sociedad Argentina de Inmunología; 2020

Simple positive CD8+ thymocytes (SP8) that develop in the thymuscould give rise either to conventional SP8 or to Innate CD8+ T cells(TIM). TIM acquire a memory phenotype during their thymic maturationand are exported to SLO as a conventional T cell. TIM play a protectiverole during the early phase of infectious processes as reportedfor certain bacteria, viral and parasite infections. Our previousresults demonstrated that during T. cruzi infection, a large numberof TIM mature in the thymus due to local production of IL-4 and IL-15,2 cytokines responsible for their maturation/maintenance process.TIM functionally act in a TCR-independent way; instead they are activatedthrough cytokines as IL-12 and IL-18. By using OT-I mice(not RAG2 KO, that carry an OVA specific TCR in most of SP8 cells)we could compare the expression of a large number of markers betweenOVA tetramer+ (OVAt+) SP8 cells (not specific for the parasite)and conventional polyclonal SP8 cells simultaneously present in thethymus of control and T. cruzi infected mice. Data demonstrate thatOVAt+ SP8 cells expressed higher levels of CD44, CD122, CD5,CD69, QA2 and decreased levels of CD24 compared to conventionalSP8 cells while other markers like CD62L, PD-1 and CD5 seemnot to be differentially expressed (p