YERSINIA ENTEROCOLÍTICA-INDUCED MO-MDSC SUPPRESS T-CELL PROLIFERATION THROUGH A NITRIC OXIDE-DEPENDENT MECHANISM

MARIANELA LEPORATI; DAVICINO RC; MARÍA S. DI GENARO; ELIÇABE, JAVIER

Buenos Aires

Congreso; REUNIÓN DE SOCIEDADES DE BIOCIENCIAS 2020; 2020

Sociedad Argentina de Inmunología

Myeloid-derived suppressor cells (MDSC) are a heterogeneouspopulation of immature myeloid cells with the ability to suppressT-cell responses. Monocytic MDSC (Mo-MDSC) and polymorphonuclearMDSC (PMN-MDSC) are the main subsets described. Yersiniaenterocolitica (Ye) is a Gram-negative bacterium that causes foodbornegastrointestinal diseases. In previous studies, we demonstratedthat Ye oral infection induces the expansion of MDSC. Thepurpose of this work was to investigate the MDSC sub-populationthat exerts the suppressive activity and underlying the mechanismbehind it. Mice of the strain C57BL/6 were infected with Ye WAP-314serotype O:8. On day 5 post-infection (p.i), MDSC were analyzed inbone marrow (BM), mesenteric lymph nodes (MLN) and spleen byflow cytometry. Furthermore, Mo-MDSC and PMN-MDSC were purifiedfrom the spleen of infected mice and their suppressor activitywas evaluated in co-cultures with purified T cells. Nitric oxide (NO)production was analyzed by nitrite quantification in culture supernatants.We found that MDSC expanded in BM and accumulated inboth MLN and spleen of infected mice, in contrast with uninfectedmice (p