Role of regulatory T cells in Yersinia enterocolitica-induced reactive arthritis in TNFRp55-/- mice

CARGNELUTTI E.; ANZULOVICH AC.; DI GENARO MS.

Potrero de los Funes, San Luis

Congreso; XLII Reunión Anual de la Sociedad Argentina de Investigación en Bioquímica y Biología Molecular (SAIB-2011); 2011

Sociedad Argentina de Investigaciones Bioquímicas

CB-P07.ROLE OF REGULATORY T CELLS IN Yersiniaenterocolitica-INDUCED REACTIVE ARTHRITIS INTNFRP55-/- MICECargnelutti E1, Anzulovich AC2, Di Genaro MS1.1Lab. of Immunopathology and Flow Cytometry, 2Lab. ofChronobiology, IMIBIO-SL, CONICET, UNSL. E-mail:ethelcargnelutti@gmail.comRegulatory T (Treg) cells suppress physiological and pathologicalimmune responses. We have demonstrated that TNFRp55-/-(KO)mice develop a severe and chronic reactive arthritis (ReA) afterYersinia enterocolitica (Ye) infection. Also, KO mice showsignificant differences of IL-10 levels at regional lymph nodes(RLN) to the joint. The aim of this work was to investigate whetherTreg cells play a role in our ReA model. We determined thefrequency of Treg cells and the Foxp3 mRNA expression. C57BL/6wild-type (WT) and KO mice were infected with Ye O:3. Seven, 14and 21 days after infection, CD4+CD25+Foxp3+ cells from RLNwere analyzed by flow cytometry; Foxp3 mRNA expression in RLNCD4+T cells was determined by RT-qPCR. We found that on day 14(arthritis onset), KO mice showed significantly lower frequency ofCD4+CD25+Foxp3+ cells, compared to WT mice (3.7%±0.13;5.1% ±0.46, respectively; p<0.05), this result was in line withrelative expression of Foxp3 mRNA (0.78±0.03; 1.2±0.03,respectively; p<0.005). In contrast, despite KO mice showedarthritis on day 21 (chronic phase), a significantly higher frequencyof Treg cells was found in these mice compared to WT (4.4%±0.27;3.4%±0.29, respectively; p<0.05). We concluded that at local site,TNFRp55 signaling influences the Foxp3 expression and Tregfrequency. Moreover, Treg decrease is involved in ReA onset inTNFRp55-/- mice.