Innate CD8+ T cells: from the thymus to the secondary lymphoid organs (SLO) in steady state versus Trypanosoma cruzi infection

SAVID-FRONTERA, CONSTANZA; RODRIGUEZ-GALAN, MARIA CECILIA; BAEZ, NATALIA S.; VIANO, MARIA ESTEFANIA; CERBÁN, FABIO

Congreso; Reunión Anual de Sociedades de Biociencia; 2020

Sociedad Argentina de Inmunología

Innate CD8+ T cells (TIM cells) are a subset of T cells that mature in the thymus as a different lineage from conventional simple positive CD8+ thymocytes (SP8). They acquire a memory phenotype during their thymic maturation and are exported to SLO as a conventional T cell. TIM cells play a protective role during the early phase of infectious processes as reported for certain bacteria, viral and parasite infections. Our previous results demonstrated that during T. cruzi infection, a large number of TIM cells mature in the thymus due to local production of IL-4 and IL-15, 2 cytokines responsible for their maturation/maintenance process. TIM cells functionally act in a TCR-independent way; instead they are activated through 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 compared the expression of a large number of markers between OVA+ SP8 cells and conventional polyclonal SP8 cells simultaneously present in the thymus of control and T. cruzi infected mice. Data demonstrate that OVA+ SP8 cells expressed higher levels of CD44, CD122, CD5, CD69, QA2 and decreased levels of CD24 compared to conventional SP8 cells while other markers like CD62L, PD-1 and CD5 seem not to be differentially expressed (p