Bordetella Parapertussis Invasion of HeLa 229 Cells and Human Respiratory Epithelial Cells in Primary Culture

Bordetella parapertussis, a respiratory tract pathogen commonly regarded as noninvasive, was found to invade HeLa 229 cell monolayers. Following treatment of the monolayers with gentamicin, numbers of viable B. parapertussis recovered were comparable to those of invasive Salmonella and Shigella isolates. Invasion occurs through a cytochalasin-sensitive process which appears to be distinct from receptor-mediated endocytosis. Hyperimmune antisera raised against filaments hemagglutinin, a major adhesion of B. pertussis, did not inhibit invasion by B. parapertussis, suggesting that alternate adhesin(s) are required for invasion. In addition, B. parapertussis was found to invade human respiratory epithelial cells in primary culture, as demonstrated in ultrathin sections viewed by transmission electron microscopy. Although viable intracellular B. parapertussis persist within HeLa cells, they do not multiply there and the monolayers remain intact, suggesting a possible mechanism of carriage for these organisms.