Characterization of Foxp3+ regulatory T cell responses during experimental Trypanosoma cruzi infection

ARAUJO FURLÁN CL; TOSELLO BOARI J; CANALE F; ARAUJO FURLÁN CL; GRUPPI A; MONTES CL; ACOSTA RODRIGUEZ EV

Congreso; First Argentinean Spring Course in Advance Immunology and LXI Reunión Anual de la Sociedad Argentina de Inmunología.; 2013

CD4+ T cells expressing CD25 and Foxp3 (Tregs) regulate immune responses and, consequently, influence the pathogenesis of infectious diseases. Regulatory response during T. cruzi infection has been poorly characterized and Treg roles remain controversial after few studies based on Treg depletion and GITR and CTLA-4 blockade. Our aim is to characterize the magnitude and quality to further elucidate the role of Treg response during experimental T. cruzi infection. For this, Foxp3-GFP mice were infected with 5000 T. cruzi tripomastigotes and Tregs (GFP+CD4+CD25+ cells) were enumerated and characterized at different days (d) postinfection (pi) by flow cytometry. The absolute numbers of Tregs remained constant or were slightly increased in all the organs studied while the numbers of effector subsets regulated by Tregs (i.e. CD4 and CD8 T cells and B cells) were greatly augmented in spleen, lymph nodes and liver but not in thymus. Thus, the ratio of Tregs to effector cells was significantly diminished in the periphery from d10 until d60pi (early chronic phase, last day of study) (spleen: d0pi 0.134±0.012 vs d20pi 0.056±0.008, p