DYNAMIC OF FOLLICULAR CYTOTOXIC CD8+T CELL RESPONSE IN TRYPANOSOMA CRUZI INFECTION

GAZZONI, YAMILA; ALMADA, LAURA; MONTES, CAROLINA LUCIA; ACOSTA RODRÍGUEZ, EVA V.; GRUPPI, ADRIANA

Congreso; REUNIÓN DE SOCIEDADES DE BIOCIENCIAS 2021; 2021

Germinal Centers (GCs) are specialized structures generated within B cell follicles (FO) in response to T cell-dependent antigens. Follicular helper T cells (Tfh) are crucial for GC formation and antibody-affinity maturation. Other GCs-protagonists are follicular cytotoxic CD8+T cells (Tfc), who share gene signatures with Tfh cells and, in some models, contribute to eliminate infected cells inside the FO.Our aim was to study protagonists of GC response in T. cruzi infection and to characterize Tfc cells. C57BL/6 mice were intraperitoneally injected with 5.000 trypomastigotes of T. cruzi (Tulahuén strain) or PBS (control group). Tfc, GC B cells, and plasmablasts (PB) were evaluated by FACS and immunofluorescence (IF) staining at different days post infection (dpi) in the spleen. The peaks of the Tfc (CD8+CXCR5+PD-1+) and PB (B220lowCD138+) response were at 18dpi and decreased at 23 dpi. These populations preceded GC-B cell(B220+FAS+GL-7+) response which peaked at 28 dpi. About 80% of Tfc were CD44+CD62-Llow and had a higher expression of Bcl-6, TCF-1, Lag-3, CD40-L and CXCR3 than non-Tfc CD8+T cells (p