B. ABORTUS RNA ACTIVATES MACROPHAGES TOWARDS A PRO-INFLAMMATORY PROFILE EARLY ON DURING INFECTION

AGUSTINA SERAFINO; JOSÉ L. MARIN FRANCO; LUIS A. CASTILLO; FEDERICO BIRNBERG-WEISS; JOSÉ R. PITTALUGA; LUCIANA BALBOA; PAULA BARRIONUEVO; M. AYELÉN MILILLO

Congreso; LXIX Reunión Anual de la Sociedad Argentina de Inmunología (SAI); 2021

Brucellosis is a zoonotic disease caused by Brucella spp bacteria. These pathogens can survive inside macrophages, persisting inside the host. We previously demonstrated that Brucella abortus(Ba) RNA is a PAMP involved in the immune evasion mediated by Ba. One of the mechanisms displayed by this bacterium is the down-modulation of MHC molecules when Th1 response is beingheld, i.e., in the presence of IFN-ϒ. Nevertheless, we acknowledged whether Ba RNA could activate macrophages early on during the infection, before Th1 response is settled. To evaluate this, M0 (undifferentiated) macrophages were stimulated with Ba RNA (10 μg/ml) and at 24 and 48 h M1 (classical macrophages) or M2 (alternative macrophages) markers were assessed by flow cytometry. Regarding M1 markers, CD86 and MHC-II expressions did not change neither at 24 nor 48 h. Surprisingly, CD64 expression was reduced in Ba RNA treated macrophages (p