The Gram-negative pathogen Bordetella bronchiseptica causes acute and chronic respiratory infection in a variety of animals. Currently, there is no vaccine to prevent these infections. To identify useful candidate antigens for such a vaccine, five B. bronchiseptica genes including amino acid ATP-binding cassette transporter substrate-binding protein (ABC), lipoprotein (PL), outer membrane porin protein (PPP), leu/ile/val-binding protein (BPP), and conserved hypothetical protein (CHP) were cloned and the recombinant proteins were expressed. The immune responses of mice to vaccination with individual recombinant proteins were measured.
Each of the tested recombinant proteins induced a high antibody titer. PPP and PL showed protective indices against challenges with B. bronchiseptica. The protection ratios were 62.5 and 50 %, respectively, compared with 12.5 % for control vaccinations. The protection ratios of ABC, BPP, and CHP were not significantly different from the controls. IgG-subtype and cytokine analysis demonstrated that PPP and PL can induce two immune responses: a humoral immune response and a cell-mediated immune response. The humoral immunity-mediated, Th2-type response dominated.
The identification of PPP and PL, which offer immune-protective potential, identifies them as candidates for the development of a diagnostic test or a vaccine for B. bronchiseptica.||