Immunogenicity of specific Bordetella pertussis surface antigens in diphtheria-tetanus-pertussis (DTP) vaccines.

The predominant causative organism of whooping cough in Australia is of a serotype which has normally been associated overseas with unvaccinated communities. Australian DTP vaccines pass the statutory mouse test for Bordetella pertussis potency but this test is now believed to be relatively insensitive to certain factors, especially the major type-specific agglutinogens, which are presumably also important in the human host-parasite relationship. Because endemic B. bronchiseptica infections make some laboratory animals unsatisfactory for testing B. pertussis agglutinin responses, we have developed a test in which young farm sheep were immunized with vaccines. Type-specific agglutinins in their sera were assayed after absorption of non-specific agglutinins by suspensions of selected bordetella strains. Three well-reputed European DTP vaccines and two recent batches of Australian DTP vaccine were tested and compared thus. All evoked significant agglutinin responses to the main agglutinogens.

Specific anti-Bordetella pertussis activities in human blood examined by enzyme-linked immunoassay and biological assay.

Enzyme-linked immunoassays have been employed in this work to measure antibodies against either pertussigen or filamentous hemagglutinin, using a urease-conjugated second antibody system. Pertussigen and filamentous hemagglutinin were obtained from the supernatants of Bordetella pertussis cultures by chromatographic procedures, and were shown to be essentially free of other proteins. Further checks have established the specificity of the enzyme-linked immunoassay-systems. Anti-pertussigen and anti-filamentous hemagglutinin antibody titers, in a pilot study of sera from normal adults, showed little correlation with the donors' pertussis contact, infection or vaccination histories. Nevertheless, the titers did correlate with the ability of the sera to neutralize the biological actions of pertussigen in mice and the haemagglutinating activity of filamentous haemagglutinin, respectively. Antibody titers of sera from patients with suspected or confirmed pertussis infection fell within the range covered by sera from normal adults. Sera from unvaccinated children (less than two months old) also showed some anti-pertussis activity that was probably maternal in origin. Further selected adult plasma samples have been compared for anti-pertussis activity by enzyme-linked immunoassays and agglutination. These samples also have been evaluated for their abilities to protect mice passively against intra-nasal and intra-cerebral challenge with Bordetella pertussis.