Cholesterol rich domains are involved in filamentous hemagglutinin-mediated attachment of Bordetella pertussis to epithelial cells.

LAMBERTI, Y; ALVAREZ HAYES, J; RODRIGUEZ, ME

Rosario

Congreso; V Congreso Argentino de Microbiología General; 2008

SAMIGE

B. pertussis is the etiologic agent of whooping cough, a reemerging infectious disease. Adhesion to respiratory epithelial cells is a central phenomenon in the pathogenesis of B. pertussis. Previous work of our group have showed that cholesterol rich domainsin the plasma membrane known as lipid rafts are involved in B. pertussis interaction with host cells. However B. pertussis adhesins implicated in this interaction has remained elusive.We here investigated whether filamentous hemagglutinin (FHA), the major adhesin of this pathogen, is involved in this cholesterol dependent interaction. Human respiratory epithelial cells (A549) treated with and without cyclodextrin, a cholesterol sequestring drug, were incubated with purified B. pertussis FHA. Cell associated FHA was assessed both by fluorescence microscopy and flow cytometry. The results showed that the depletion of cholesterol led to a significant decrease in the amount of cell associated FHA. Using a cold detergent extraction method we furthermore demonstrated that FHA is isolated in association with detergent resistant membrane fractions ?DRMs- (so called lipid raft) of A549 cell unless DRMs were isolated in the presence of saponin, a lipid raft disrupting drug, in which case FHA lossess its capacity to associate with these domains. Our results seems to indicate that B. pertussis interaction with cholesterol rich domains might centrally depends on FHA although we cannot exclude the possibility that other adhesins were also involved.