B. ABORTUS RNA THROUGH EGF-LIKE LIGANDS INDUCES THE RETENTION OF MHC-I MOLECULES WITHIN THE GOLGI APPARATUS IN HUMAN MONOCYTES

MILILLO, M. AYELÉN; VELASQUEZ, LIS N.; DELPINO, VICTORIA; TROTTA, ALDANA; POZNER, ROBERTO G.; ISTURIZ, MARTÍN; GIAMBARTOLOMEI, GUILLERMO; BARRIONUEVO, PAULA

Buenos Aires

Congreso; I Meeting LASID FAIC SAI; 2015

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