Breaching barriers: the interaction of Brucella with epithelial cells

PAULA V. LOPEZ; AGOSTINA B. GIMÉNEZ; CECILIA CZIBENER; JUAN E. UGALDE

Congreso; Brucellosis Research Conference 2017; 2017

Epithelial cells are the first barriers many infectious agents encounter during infection and all pathogenic bacteria have evolved a wide range of molecules to facilitate adhesion, invasion and multiplication in these cell types. Many of these adhesins target specific surface proteins of the host cells promoting tissue tropisms and invasion. Although many molecular determinants that participate in the intracellular phase have been identified and characterized we still know very little about the mechanisms Brucella uses to adhere, invade and trespass epithelial barriers. We have recently identified and began to characterize a series of virulence factors involved in the adhesion and invasion of epithelial cells using two models: HeLa and polarized Madin-Darby Canine Kidney (MDCK) cells. Our results indicate that Brucella has evolved a series of mechanisms that allow the bacterium to actively adhere and invade these cells and that this invasion occurs through specific regions of the plasmatic membrane. A detailed analysis of the replicative cycle in MDCK showed that Brucella actively modulates its egress in a process that requires the modulation of actin polymerization and that this exit also occurs through a specific membrane. These results indicate that Brucella deploys a battery of virulence factors devoted to invade and trespass epithelial barriers.