The specificity of antisera against Bordetella pertussis examined by bacterial agglutination.

The specificity of conventional, adsorbed antisera against agglutinogens 1, 2, and 3 of Bordetella pertussis was examined by slide agglutination and by agglutination in microtitre wells. Unadsorbed hyperimmune sera showed higher agglutinating activity against autologous or homologous cells than against cells of heterologous serotype. Adsorption of sera with heterologous cells increased the serotype specificity considerably. In spite of extensive adsorption, these anti-agglutinogen sera were still found to cross-react with B. parapertussis and/or B. bronchiseptica strains. Adsorption experiments with B. pertussis hyperimmune sera against serotype 1-, 1.2-, and 1.3-organisms demonstrated that the cross-reacting surface antigens differed from the agglutinogens 1, 2, and 3. Thus, in making species-specific reagents for diagnostic use it may be of value to include adsorption with B. parapertussis and probably with B. bronchiseptica. Limited data indicated that there is no need to use B. avium for adsorption. The agglutination assays were also used to test three monoclonal antibodies stated to be specific for the agglutinogens 1, 2, and 3, respectively. Some anomalous behaviour for the anti-agglutinogen 1 reagent was found, whereas the anti-agglutinogen 2 and 3 reagents corresponded well with the present polyclonal factor sera.