Although B. bronchiseptica efficiently infects a wide range of mammalian hosts and efficiently spreads among them, it is rarely observed in humans. In contrast to the many other hosts of B. bronchiseptica, humans are host to the apparently specialized pathogen B.
pertussis, the great majority having immunity due to vaccination,
infection or both. Here we explore whether immunity to B.
pertussis protects against B. bronchiseptica
infection. In a murine model, either
infection or vaccination with B.
pertussis induced
antibodies that recognized
antigens of B. bronchiseptica and protected the lower respiratory tract of mice against three phylogenetically disparate strains of B. bronchiseptica that efficiently infect naïve animals. Furthermore, vaccination with purified B.
pertussis-derived
pertactin, filamentous
hemagglutinin or the human
acellular vaccine,
Adacel, conferred similar protection against B. bronchiseptica challenge. These data indicate that individual immunity to B.
pertussis affects B. bronchiseptica
infection, and suggest that the high levels of herd immunity against B.
pertussis in humans could explain the lack of observed B. bronchiseptica transmission. This could also explain the apparent association of B. bronchiseptica
infections with an immunocompromised state.