INHIBITION OF MAJOR HISTOCOMPATIBILITY COMPLEX CLASS I (MHC-I) BY BRUCELLA ABORTUS IS AN EARLY EVENT DURING INFECTION AND INVOLVES THE EGF RECEPTOR PATHWAY

VELAZQUEZ LIS; DELPINO M. VICTORIA; MILILLO AYELÉN; GIAMBARTOLOMEI GUILLERMO H.; BARRIONUEVO PAULA

Mar del Plata, Buenos Aires

Congreso; LIX REUNIÓN CIENTÍFICA ANUAL Sociedad Argentina de Investigación Clínica LXII REUNIÓN ANUAL Sociedad Argentina de Inmunología; 2014

Brucella abortus is able to persist inside the host despite thedevelopment of a potent CD8+ T cell response. We have recentlyreported the ability of B. abortus to inhibit the IFN-γ-induced cellsurface expression of MHC-I molecules on human monocytes.MHC-I down-modulation resulted in a diminished CD8+ cytotoxicT cell response and was dependent on bacterial viability. Theaim of this study was to further characterize this phenomenonby studying its kinetics and if it elicits a bystander effect. Forthis, THP-1 cells were infected with a virulent strain of B. abortus(S2308), a rough strain (RB51) or a mutant strain lacking the V irBType IV secretion system (virB10-) in the presence of IFN-γ for 48h. MHC-I expression was then evaluated by flow cytometry. All3 strains were able to diminish the IFN-γ-induced expression ofMHC-I molecules (p