Effectiveness of orally administered Bordetella pertussis vaccine in mice.

Oral administration of killed Bordetella pertussis organisms to mice results in increased resistance to an intracerebral infection with virulent B. pertussis cells. The rate of survival is dependent on the dose of antigen. But besides specific systemic immunity, which is persistent over a long period, also transient non-specific resistance is increased. These effects are evidently induced without penetration of bacterial substances into the circulation.