Role of Adhesins and Toxins in Invasion of Human Tracheal Epithelial Cells by Bordetella pertussis

Abstract

Bordetella pertussis, the agent of whooping cough, can invade and survive in several types of eukaryotic cell, including CHO, HeLa 229, and HEp-2 cells and macrophages. In this study, we analyzed bacterial invasiveness in nonrespiratory human HeLa epithelial cells and human HTE and HAE0 tracheal epithelial cells. Invasion assays and transmission electron microscopy analysis showed that B. pertussis strains invaded and survived, without multiplying, in HTE or HAE0 cells. This phenomenon was bvg regulated, but invasive properties differed between B. pertussis strains and isolates and the B. pertussis reference strain. Studies with B. pertussis mutant strains demonstrated that filamentous hemagglutinin, the major adhesin, was involved in the invasion of human tracheal epithelial cells by bacteria but not in that of HeLa cells. Fimbriae and pertussis toxin were not found to be involved. However, we found that the production of adenylate cyclase-hemolysin prevents the invasion of HeLa and HTE cells by B. pertussis because an adenylate cyclase-hemolysin-deficient mutant was found to be more invasive than the parental strain. The effect of adenylate cyclase-hemolysin was mediated by an increase in the cyclic AMP concentration in the cells. Pertactin (PRN), an adhesin, significantly inhibited the invasion of HTE cells by bacteria, probably via its interaction with adenylate cyclase-hemolysin. Isolates producing different PRNs were taken up similarly, indicating that the differences in the sequences of the PRNs produced by these isolates do not affect invasion. We concluded that filamentous hemagglutinin production favored invasion of human tracheal cells but that adenylate cyclase-hemolysin and PRN production significantly inhibited this process.

Role of ADP-Ribosyltransferase Activity of Pertussis Toxin in Toxin-Adhesin Redundancy with Filamentous Hemagglutinin duringBordetella pertussisInfection

“…In all cases, only FHA, not PT, was required for cell adherence of B. pertussis. These results are in agreement with several recent reports (3,11,42). However, PT-deficient B. pertussis has previously been shown to adhere less than normal B. pertussis to human and rabbit ciliated respiratory epithelial cells (40,41), suggesting that it might act as an adhesin, an activity allocated to its carbohydrate binding sites located in the B moiety of the toxin (17,33).…”

Bordetella pertussisInfection in 2-Month-Old Infants Promotes Type 1 T Cell Responses

“…Actually, Ag-specific IFN-␥ secretion in the infected 2-mo-old children was at the same order of magnitude as that induced by PHA in nonimmune children of the same age. Although B. pertussis has traditionally been viewed as an extracellular pathogen, data accumulated over the last decade indicate that it is also able to survive intracellularly within macrophages and epithelial cells (32,33). However, intracellular survival of B. pertussis is not required for the induction of a strong Th1 cellular immune response, as similar responses were induced by the s.c. administration of whole-cell pertussis vaccine not containing any viable microorganism.…”

Cyclic AMP-Elevating Capacity of Adenylate Cyclase Toxin-Hemolysin Is Sufficient for Lung Infection but Not for Full Virulence of Bordetella pertussis

“…Indeed, the cellpermeabilizing and cell-invasive AC enzyme activities of CyaA synergized in provoking neutrophil recruitment and inflammatory damage of infected lung tissue, which could be underlined by at least three already known mechanisms. First, CyaA-mediated elevation of the cAMP concentration in tracheal epithelial cells was previously shown to elicit production of the IL-6 cytokine, which is known to activate cytotoxic action of neutrophils at the site of infection (2,40,52). Second, cAMP signaling of CyaA was shown to induce cyclooxygenase 2 (COX-2) expression in macrophages, and this would yield release of prostaglandins that serve in chemoattraction of neutrophils (53).…”