Mdsc are expanded in intestinal mucosa and spleen after oral infection with yersinia enterocolitica and induced suppression through a nitric oxide - dependent mechanism.

ROBERTO DAVICINO; MARIANELA LEPORATI; JAVIER ELIÇABE; SILVIA DI GENARO

Mar del Plata

Congreso; Reunión Conjunta de la Sociedad Argentina de Investigación Clínica, Sociedad Argentina de Inmunología y la Sociedad Argentina de Fisiología; 2018

MDSC represent a heterogeneous population of largely immature myeloid cells that are characterized by display potent immune suppressive activity. Yersinia enterocolitica (Ye) are a Gram-negative bacteria that causes food-borne acute or chronic gastrointestinal diseases. However, the role of MDSCs in Ye infection has not been determined. So the purpose of this work, was to elucidate whether oral Ye infection induces the expansion of MDSCs and to define the mechanism through which these cells exert their suppressive activity. Therefore, C57BL/6 mice were infected with Ye WAP-314 serotype O:8. On days 5, 10 and 20 post-infection (p.i), cell infiltration in mesenteric lymph nodes (MLN), Peyer´s patches (PP) and spleen was analyzed. Suppressive activity was determined by MTT assay and nitrite levels were measured with Griess reagent. In vitro iNOS inhibition was done with Aminoguanidine (AG) and Arginase 1 activity was determined indirectly through the quantification of urea. We found that Ye-infected mice presented an increase in the frequencies of CD11b+Gr-1+ cells in PP, MLN and spleen on days 5, 10 and 20 p.i, compared to uninfected mice (p