Role of adhesins and toxins in invasion of human tracheal epithelial cellsby Bordetella pertussis

Bordetella pertussis, the agent of whooping cough, can invade and survive i n several types of eukaryotic cell, including CHO, HeLa 229, and HEp-2 cell s and macrophages. In this study, we analyzed bacterial invasiveness in non respiratory human Beta epithelial cells and human HTE and HAE0 tracheal epi thelial cells. Invasion assays and transmission electron microscopy analysi s showed that B. pertussis strains invaded and survived, without multiplyin g, in HTE or HAE0 cells. This phenomenon was bvg regulated, but invasive pr operties differed between B. pertussis strains and isolates and the B. pert ussis reference strain. Studies with B. pertussis mutant strains demonstrat ed that filamentous hemagglutinin, the major adhesin, was involved in the i nvasion of human tracheal epithelial cells by bacteria but not in that of H eLa cells. Fimbriae and pertussis toxin were not found to be involved. Howe ver, we found that the production of adenylate cyclase-hemolysin prevents t he invasion of HeLa and HTE cells by B. pertussis because an adenylate cycl ase-hemolysin-deficient mutant ass found to be more invasive than the paren tal strain. The effect of adenylate cyclase-hemolysin was mediated by an in crease in the cyclic AMP concentration in the cells, Pertactin (PRN), an ad hesin, significantly inhibited the invasion of HTE cells by bacteria, proba bly ria its interaction with adenylate cyclase-hemolysin. Isolates producin g different PRNs were taken up similarly, indicating that the differences i n the sequences of the PRNs produced by these isolates do not affect invasi on. We concluded that filamentous hemagglutinin production favored invasion of human tracheal cells but that adenylate cyclase-hemolysin and PRN produ ction significantly inhibited this process.