CONICET | Buscador de Institutos y Recursos Humanos

B. parapertussis (Bpp) is one of the causative agents of whooping cough and a key factor contributing to its reemergence. The developmentof improved strategies to control it requires identifying themechanism of persistence within the host to eventually eradicate thecarriage. We previously found that an intracellular stage in epithelialcells might be important for its persistence. In that work we found atropism of Bpp for tight junctions (TJ). Like for other pathogens, thismight indicate the existence of a mechanism to subvert epithelialbarrier function. We here investigated the role of the barrier functionduring Bpp infection. To this end we used the 16HBE14o- bronchialcell line that polarize in vitro and form TJ. Two experimental modelswere used. A fully 7-day polarized confluent monolayer in whichapical and basolateral (BL) components are largely separated byTJ and a 1-day confluent monolayer, which lacks of TJ and hencebarrier function. Cells were infected with Bpp and the outcome ofthis interaction was evaluated. Microscopy analysis showed that 6 hafter infection the attachment and internalization were higher in the1-day model than in the 7-day model, indicating that the infectionefficiency increased when barrier function are absent and Bpp accessBL components. We further evaluated how Bpp accesses theBL components in a monolayer with intact TJ. Microscopy analysisshowed that early after infection of the 7-day model Bpp adheres toand progressively disrupts TJ in an adenylate cyclase toxin (CyaA)dependent way, suggesting that Bpp might access the BL componentsby subverting epithelial barrier. Accordingly, a CyaA defectivemutant showed a reduced efficiency to access the intracellular locationin a 7-day model with intact TJ. These results suggest thatCyaA-mediated epithelial barrier disruption might grant Bpp accessto the intracellular location of epithelial cells and/or the possibility todisseminate to underlying tissues.