DIFFERENT STRATEGIES TO INHIBIT MAJOR HISTOCOMPATIBILITY COMPLEX MOLECULES EXPRESSION EMPLOYED BY BRUCELLA ABORTUS.

VELAZQUEZ, LIZ N.; MILILLO, M.A.; DELPINO, MARIA V.; POZNER, ROBERTO G.; TROTTA, A; FERNANDEZ, P; LANG, R; MERCOGLIANO, MF; SCHILLACI, R; GIAMBARTOLOMEI, GUILLERMO H.; BARRIONUEVO, PAULA

CABA

Congreso; IV LASID Meeting / LXIII Argentinean Immunology Society Meeting / II French-Argentinean Immunology Meeting.; 2015

Sociedad Argentina de Inmunologia.

Despite the cytotoxic CD8+ T cell responses elicited by Brucella abortus, this intracellular pathogen is capable of surviving inside macrophages establishing a chronic infection. We recently reported that B. abortus RNA, described as a vita-PAMP, is able to down-modulate the IFN-γ-induced MHC-I expression on human monocytes. Also, we demonstrated that B. abortus RNA mimics the intracellular retention of MHC-I within the Golgi apparatus observed with the infection. The aim of this study was to further characterize the component and pathways involved in MHC-I down-modulation. For this, RNases-treated B. abortus RNA was employed to stimulate human monocytic THP-1 cells in the presence of IFN-γ for 48 h. Then, the expression of MHC-I molecules was evaluated by flow cytometry. Surprisingly, completely degraded RNA was able to inhibit MHC-I expression to the same extent as intact RNA (p