ABSTRACT
Bordetella pertussis is the causative agent of pertussis or whooping cough, a serious disease of the respiratory tract. B. pertussis strains produce two serologically distinct fimbriae that were first identified as agglutinogens, i.e., antigens that induce the production of antibodies that agglutinate the bacteria. The fact that Bordetella fimbriae show antigenic variation suggests that antibodies directed against these structures are very effective in preventing dissemination of the bacteria. Serotype 2 and 3 fimbriae are mainly composed of subunits, designated Fim2 and Fim3, with molecular weights of 22,500 and 22,000, respectively. Superimposed on the coordinate regulation by the bvg locus, the major subunit genes are subject to a second type of control that involves random events. Studies in animal models have also provided evidence that fimbriae are important protective antigens. Immunization of mice with fimbriae conferred significant protection against colonization of the respiratory tract.
