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.

Stainer and Scholte's pertussis medium with an alternative buffer.

A comparative study of the Stainer and Scholte chemically defined growth medium (SS) for Bordetella pertussis, and a modification of it (MSS), was made. The Tris buffer which is reported to have adverse effects was replaced in MSS with sodium glycerophosphate. By using generation time as a measure of the growth promoting properties of the media, we found that the MSS was superior to SS for B. pertussis strain CN5612/67, which was used as a vaccine strain in Norway. Additionally by employing the 'dilution to extinction' method we showed that MSS supported B. pertussis growth from smaller inocula than the original SS medium. No significant differences in the quality of vaccines made from organisms grown in the two alternative media were observed in animal tests for potency and safety. The difference in buffers in SS and MSS had no influence on the formation of the agglutinogens, as tested by agglutination with specific factor sera. It was confirmed that liquid media gave a better total expression of the agglutinogens than solid media.