Immune efficacy of five novel recombinant Bordetella bronchiseptica proteins.

Abstract

BACKGROUND: 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. RESULTS: 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. CONCLUSION: 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.