Label-free proteomic analysis of intracellular Bordetella pertussis.

LAMBERTI, YANINA; SCHMIDT, FRANK; SURMANN, KRISTIN; CAFIERO, HILARIO; RODRIGUEZ, MARÍA EUGENIA

Dublin

Simposio; 10th International Symposium on Bordetella; 2013

Bordetella International Society

Although usually regarded as a non-invasive pathogen, a number of studies suggest that B. pertussis is able to enter inside the host cell. We recently found that B. pertussis not only survives inside human macrophages but also replicates in non-acidic compartments. In the present study, we investigated whether B. pertussis is also able to hide inside epithelial respiratory cells and proliferate from there. To this end, A549 cells, a human alveolar epithelial cell line, were infected with B. pertussis and both the invasion process and intracellular trafficking were studied. We found that bacterial internalization by respiratory epithelial cells was inhibited by agents that disrupt lipid rafts, microtubules, and tyrosine kinase activity. Confocal microscopy studies further indicated that once inside the cell, a significant proportion of intracellular bacteria (54 ± 7%) evades lysosomal pathway and remains viable in non-acidic LAMP1-negative compartments for more than 48 h after infection. In addition, intracellular B. pertussis was found able to repopulate the extracellular environment after complete elimination of extracellular bacteria with Polymyxin B. These results suggest that B. pertussis is able to enter and survive within respiratory epithelial cells potentially contributing to host immune evasion and persistence.