Inhibition of Major Histocompatibility Complex Class I (MHC-I) by Brucella abortus is an early event during infection and involves the EGF receptor pathway.

VELASQUEZ, LIS N.; DELPINO, VICTORIA; MILILLO, M. AYELÉN; GIAMBARTOLOMEI, GUILLERMO; BARRIONUEVO, PAULA

Mar del Plata, Buenos Aires

Congreso; LIX Reunión Científica Anual de la Sociedad Argentina de Investigación Clínica (SAIC). LXII Reunión Anual de la Sociedad Argentina de Inmunología (SAI).; 2014

Sociedad argentina de Investigación Clínica-Sociedad Argentina de Inmunología

Brucella abortus is able to persist inside the host despite the development of a potent CD8+ T cell response. We have recently reported the ability of B. abortus to inhibit the IFN-γ-induced cell surface expression of MHC-I molecules on human monocytes. MHC-I down-modulation resulted in a diminished CD8+ cytotoxic T cell response and was dependent on bacterial viability. The aim of this study was to further characterize this phenomenon by studying its kinetics and if it elicits a bystander effect. For this, THP-1 cells were infected with a virulent strain of B. abortus (S2308), a rough strain (RB51) or a mutant strain lacking the VirB Type IV secretion system (virB10-) in the presence of IFN-γ for 48 h. MHC-I expression was then evaluated by flow cytometry. All 3 strains were able to diminish the IFN-γ-induced expression of MHC-I molecules (p