Cholesterol-dependent attachment of human respiratory cells byBordetella pertussis

Abstract

Bordetella pertussis is a re-emerging human respiratory pathogen whose infectious process is not fully understood, hampering the design of effective vaccines. The nature of bacterial attachment to host cells is a key event in the outcome of the infection. However, host cell receptors involved in B. pertussis colonization of the respiratory tract are still under investigation. Here, we report that cholesterol-rich domains are involved in B. pertussis adhesion to epithelial cells. Treatment of A549 cells with cholesterol-sequestering drugs such as methyl-beta-cyclodextrin, nystatin, or filipin resulted in a significant decrease of B. pertussis attachment. Confocal laser microscopy studies showed B. pertussis associated with cholesterol-rich domains. Accordingly, B. pertussis was found in detergent-resistant membrane domain fractions isolated from bacterial-infected A549 cells. Our results indicate a main role of filamentous hemagglutinin, an environmentally regulated virulence factor, in this interaction, and a specific affinity for cholesterol, one of the major components of tracheal secretions, which might additionally contribute to the effective colonization of the respiratory tract.

Bordetella parapertussis Circumvents Neutrophil Extracellular Bactericidal Mechanisms

“…Exocytosis of the lysosomal enzyme β-glucuronidase was determined as previously described [38], with minor modifications. Briefly, 2x10 5 neutrophils were incubated with bacteria at a multiplicity of infection (MOI) of 300 for 10 min at 37°C and centrifuged at 300 x g. Supernatants were further centrifuged at 10,000 x g for 10 min to eliminate bacteria.…”

Bordetella pertussisentry into respiratory epithelial cells and intracellular survival

“…The drugs (purchased from Sigma) were maintained throughout the experiment. In separate experiments, cells were pretreated with 10 mM methyl‐ß‐cyclodextrin (MßCD; Sigma) plus 5 μg mL −1 of lovastatin (Sigma) for 15 min at 37 °C as described previously (Lamberti et al ., ) before infection with B. pertussis . In these experiments, lovastatin (5 μg mL −1 ) was maintained throughout the infection period.…”

Bordetella pertussisand pertactin-deficient clinical isolates: lessons for pertussis vaccines

“…It is a 220-kDa secreted protein encoded by fhaB that is capable of interacting with various cell types [6] through its multiple binding domains. FHA-mediated adherence of B. pertussis to the respiratory epithelium is in addition enhanced by AC-Hly [44] and the presence of cholesterol containing lipid rafts [45]. FHA might also possess immunomodulatory activities by acting on macrophages, dendritic cells and inflammation [46].…”