Analysis of cells involved in germinal center reaction in Trypanosoma cruzi infection.

GAZZONI, YAMILA; ACOSTA RODRIGUEZ, EVA V; MONTES, CAROLINA L.; ALMADA, LAURA; GRUPPI, ADRIANA

Fairmont Banff Springs, Banff, AB, Canada

Simposio; Keystone Symposia: T Cell Memory joint with B Cell Renaissance: Epigenetics, Regulation and Immunotherapy.; 2020

Keystone symposia

Analysis of cells involved in germinal center reaction in Trypanosoma cruzi infectionGazzoni Y 1 , Almada L 1 , Montes CL 1 , Acosta-Rodriguez EV 1 , Gruppi A 1 .1 Centro de Investigaciones en Bioquímica Clínica e Inmunología (CIBICI)-CONICET,FCQ-Universidad Nacional de Córdoba, Argentina.Germinal Centers (GCs) B cells can differentiate into antibody-secreting cells and memory Bcells in response to T cell-dependent antigens. Within GCs, follicular helper T cells (Tfh) arecrucial for afnity maturation. Other GCs-protagonists are follicular cytotoxic CD8+T cells (Tfc)whose function is not well established. However, it is known that Tfc share Tfh-relatedmolecules.Our aim was to study the response of Tfh and Tfc, the GC reaction and the presence ofplasmablast during T. cruzi infection. For this goal, C57BL/6 mice were intraperitoneally infectedwith 5.000 trypomastigotes (Tulahuén strain) and the frequency and number of the populationsmentioned above were evaluated by flow cytometry at different days post infection (dpi) in thespleen and lymph nodes. Mice injected with PBS were used as control group.In the spleen, we observed that the peak of the Tfh (CD4+CXCR5+PD-1+ICOS+), Tfc(CD8+CXCR5+PD-1+ICOS+) and plasmablast (B220 lo CD138+) response was at 18dpi. Inlymph node, the peak of Tfh and plasmablast response was at 23dpi while Tfc, at 18dpi. Theseresponses preceded GC-B cells response (B220+FAS+GL-7+Bcl-6+) which peaked at 28 dpi.Tfc exhibited the higher frequency of cells specific for the immunodominant peptide TSKB20and higher frequency of CD107a+ and IFN- γ, TNF- α and Granzyme B producing cells thannon-Tfc (CD8+CXCR5 neg PD-1 neg ) (p