Mitochondrial characterization of CD8 T cells during Trypanosoma cruzi infection.

HELLRIEGEL MF, ANA Y, BAIGORRI RE, VAZQUEZ VIGNALE, ME, CERBAN FM, STEMPIN CC

Mar del Plata

Congreso; Reunión de Sociedades de Biociencias 2022 - LXX Reunion Anual de la Sociedad Argentina de Imunologia.; 2022

We have previously demonstrated that acute T. cruzi infection triggers mitochondrial ROS (mROS) production and mitochondrial alterations in effector (E) CD4 T cells leading to functional changes and apoptosis. Moreover, it has been shown that mitochondrial membrane potential (MMP) and mROS levels are important for E and memory CD8 T cell function. The aim of this work was to evaluate metabolic and mitochondrial parameters in CD8 T cells during acute phase (AP) of T. cruzi infection. Then, spleen cells were isolated from non-infected (NI) or AP infected BALB/c mice (with 500 trypomastigotes, at 19 days post infection). Mitochondrial parameters were measured by FACS in total (Tot) and E (CD44+) CD8 T cells combining MMP-dependent (MTst) and MMP-independent mitochondrial dyes (MTgr) while mROS was tested using MitoSOX. We gated on MTgr+MTst- cells to identified T cells with depolarized mitochondria or MTgr+MTst+ as cells with normal mitochondria. We found an increase in the frequency of CD8mROS and CD8CD44mROS producing cells in spleen of AP compared to NI mice (p0.005;p0.05) compatible with cell activation. However, we observed higher levels of mROS being produced by Tot and E CD8 T cells with depolarized mitochondria (p0.005;p0.001) and the frequency of these cells is increased in AP mice (p0.005). Next, we test if PD1 expression is related to accumulation of depolarized mitochondria. In the AP of infection, a higher proportion of E CD8 T cells express PD1 and showed loss of MMP (MTst-PD1+) compared to cells with an activated phenotype that had conserved MMP (MTst+PD1+)(p0.0001). Besides, Tot and E CD8 T cells with loss of MMP and ROSm production exhibited reduced functional activity measured by lower levels of 2NBDG uptake, a fluorescent glucose analog, compared to cells with conserved MMP (p0.0005;p0.005). These results showed that study of mitochondrial parameters in CD8 cells could also be relevant to understand the immune response in T. cruzi infection.