P3-11 In-vitro model of macrophages bovine cell for the characterization of pathogenic mechanisms of bovine brucellosis.

Abstract

Brucella infection, affecting several animal species, constitutes one of the main zoonosis worldwide with a high economic impact. Disease pathogenicity is mainly associated with the ability of Brucella to evade the host immune system by surviving inside both phagocytic and non-phagocytic cells, especially macrophages, dendritic cells and granulocytes. This leads to a chronic persistent infection, in a mechanism notyet completely characterized. The macrophages, among cells of the innate immune system, constitute the first defense line against pathogens and an important immuno-modulating determinant. For this reason, the investigation on Brucella strains behavior inside macrophages could be essential to better understand and define the pathogenic mechanisms in humans and host species. In this context, we investigated the virulence of B. melitensis and B. abortus, the Brucella strains with the highest zoonotic potential, on BoMac cells, anin vitro cellular model of bovine peripheral macrophages. This study has the purpose of characterizing the bovine-pathogen interaction and developing an in vitro system serving as a reference model of bovine brucellosis infection. We observed the internalization of both B. melitensis and B. abortus in BoMac macrophages, their survival and proliferation inside host cells up to 72h from infection. Further investigations are ongoing on host gene expression and production of pro- and anti-inflammatory cytokines to characterize the bovine macrophages immuno-modulating response in the in vitro infection model. The characterization of pathogen virulence factors and the host cells molecular response, constitute the basis for understanding infectious disease mechanisms and development of more effective tools for their control.