BRUCELLA ABORTUS RNA INHIBITS THE EXPRESSION OF MAJOR HISTOCOMPATIBILITY COMPLEX CLASS I (MHC-I) MOLECULES IN HUMAN MONOCYTES

MILILLO AYELÉN; VELAZQUEZ LIS; DELPINO M. VICTORIA; 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

Sociedad argentina de Investigación Clínica-Sociedad Argentina de Inmunología

Brucella abortus elicits a vigorous Th1 immune responsewhich activates cytotoxic T lymphocytes. However, B. abortusis able to persist inside its host and establishes a chronic infection.We recently reported that infection of human monocytes/macrophages with B. abortus inhibits the IFN-γ-induced MHC-Icell surface expression down-modulating cytotoxic CD8+ T cellresponses. MHC-I down-modulation depends on bacterial viabilityand results from the capacity of B. abortus to retain the MHC-Imolecules within the Golgi apparatus. However, the componentsof B. abortus involved in this phenomenon remained unknown.Prokaryotic RNA has been recently characterized as a class ofviability-associated PAMPs (vita-PAMPs). Thus, the aim of thisstudy was to evaluate the effect of B. abortus RNA on IFN-γ-induced MHC-I expression. For this, human monocytic THP-1cells were incubated with B. abortus RNA (0.1-20 μg/ml) in thepresence of IFN-γ for 48 h. The expression of MHC-I molecules(HLA-ABC) was then, evaluated by flow cytometry. B. abortusRNA significantly (p