Bordetella pertussis Entry Into Respiratory Epithelial Cells and Intracellular Survival

LAMBERTI, YANINA; GORGOJO, JUAN PABLO; RODRIGUEZ, MARÍA EUGENIA

Dublin

Simposio; 10 th International Symposium on Bordetella; 2013

Trinity Biomedical Sciences Institute, Trinity College Dublin

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 survive inside human macrophages but also replicate 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 investigated. 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.