RESPONSES OF γδ T CELLS TO SOLUBLE FACTORS RELEASED BY SHIGA TOXIN -TREATED INTESTINAL EPITHELIAL CELL LINE OR BY ESCHERICHIA COLI O157:H7

MELILLO, NADIA CAROLINA; ROSSO, DAVID ANTONIO; ROSATO, MICAELA; SACERDOTI, FLAVIA; SHIROMIZU, CAROLINA MAIUMI; SABBIONE, FLORENCIA; AMARAL, MARÍA M.; JANCIC, CAROLINA

San Luis

Congreso; LXXI Reunión Anual de la Sociedad ARgentina de Inmunología; 2023

SAI

Hemolytic uremic syndrome (HUS) is a serious public health concern that mainlyaffects children younger than 5 years old. They have a higher risk of developingsevere consequences such as acute or chronic renal injury. HUS associated withdiarrhea, hemolytic anemia, and thrombocytopenia is a consequence of Shigatoxin (Stx)-producing Escherichia coli (STEC) infection. Stx type 2 (Stx2)-producing strains are associated with severe cases of HUS in Argentina, wherethat disease is endemic. γδ T cells are a specialized subset of T cells, which actas early sensors of cellular stress and infection. They can exert cytotoxicityagainst infected cells and produce cytokines and chemokines. Previously, weevaluated the response of γδ T cells to stress signals emulating an inflammatorymicroenvironment that could be developed at the gut epithelial barrier. In thiswork, we aimed to evaluate the response of human peripheral blood γδ T cells tosupernatants obtained from the intestinal epithelial cell line HCT-8 treated or notwith Stx2 (0.01 - 1000 ng/ml). As well, we studied the response of γδ T cells tosoluble factors released by Escherichia coli O157:H7 strain 125/99 whichproduce Stx2 (STEC 125/99), and from Stx2 non-producing bacteria(STEC125/99deltaStx2), as control. For that purpose, we analyzed in γδ T cells,after 24 h incubation with the supernatants mention above, the CD69 expressionby flow cytometry, and cytokine (IFN- γ and TNF-α) production by ELISA. As aresult, we observed that the treatment of γδ T cells with HCT-8 supernatantstreated with Stx2 did not induce changes in lymphocyte activation compared withnon-treated cells (n= 11). In addition, similar CD69 expression and cytokineproduction were observed when γδ T cells were expose to both Escherichia colisupernatants obtained from Stx2-producing bacteria and their controls (n= 7). Inconclusion, our results suggest that γδ T cells seem to be not sensitive to thestress signals released by Stx2-stimulated HCT-8 or by STEC.