The virulence factors of Bordetella pertussis: a matter of control

Bordetella pertussis is the causative agent of whooping cough, a contagious childhood respiratory disease. Increasing public concern over the safety o f whole-cell vaccines led to decreased immunisation rates and a subsequent increase in the incidence of the disease. Research into the development of safer, more efficacious, less reactogenic vaccine preparations was concentr ated on the production and purification of detoxified B. pertussis virulenc e factors. These virulence factors include adhesins such as filamentous hae magglutinin, fimbriae and pertactin, which allow B. pertussis to bind to ci liated epithelial cells in the upper respiratory tract. Once attachment is initiated, toxins produced by the bacterium enable colonisation to proceed by interfering with host clearance mechanisms. B. pertussis co-ordinately r egulates the expression of virulence factors via the Bordetella virulence g ene (bvg) locus, which encodes a response regulator responsible for signal- mediated activation and repression. This strict regulation mechanism allows the bacterium to express different gene subsets in different environmental niches within the host, according to the stage of disease progression. (C) 2001 Federation of European Microbiological Societies. Published by Elsevi er Science B.V. All rights reserved.