Serum antibody responses to the outer membrane proteins of Bordetella pertussis

The serum antibody responses to the outer membrane proteins, purified filamentous hemagglutinin, and leukocytosis-promoting factor of Bordetella pertussis were examined in mice and children immunized with pertussis whole-cell vaccine. It was found that, although there were many similarities in the responses of mice and children, there were important differences. Sera from vaccinated mice reacted strongly with purified filamentous hemagglutinin and gave weak or undetectable responses to the components of purified leukocytosis-promoting factor. The converse was found with sera from vaccinated children. Antibodies to leukocytosis-promoting factor may thus be of importance in protecting children against pertussis, although they appear to play no role in the active mouse protection test for vaccine efficacy. These results cast doubt on the value of the mouse as an animal model for the potency testing of extracted acellular pertussis vaccines.