Cloning and immunologic characterization of a truncated Bordetella bronchiseptica filamentous hemagglutinin fusion protein

Filamentous hemagglutinin (FHA) is an outer-membrane associated adhesin con served within the genus Bordetella. FHA provides protection against B. pert ussis infections in humans and is a component of acellular whooping cough v accines. Furthermore, FHA serves as a protective antigen in several animal models of infection with B. bronchiseptica and may serve as a protective an tigen of canine bordetellosis. In this study, polyclonal anti-B. per tussis FHA antiserum was used to identify an immunoreactive clone from the genomi c DNA library of a canine B. bronchiseptica field isolate. The nucleotide a nd predicted amino acid sequences of the immunoreactive clone were compared to fhaB and FhaB from B. pertussis revealing 94% identity at the nucleic a cid level, and 86% identity at the protein level. A truncated fusion protei n (FHAt) was prepared which included a conserved domain homologous to the i mmunodominant region in the FHA of B. pertussis [Leininger E, Bowen S, Rena uld-Mongen G, Rouse JH, Menozzi FD, Locht C, Heron I, Brennan MJ. Immunodom inant domain present on the Bordetella pertussis vaccine component filament ous hemagglutinin. J. Infect. Dis. 1997;175:1423-1431; Wilson DR, Siebers A , Finlay BE. Antigenic analysis of Bordetella pertussis filamentous hemaggl utinin with phage display libraries and rabbit anti-filamentous hemagglutin in polyclonal antibodies. Infect. Immun. 1998;66:4884-4894]. FHAt was shown to be safe and antigenic in rabbits. FHAt induced the formation of antibod ies that inhibit the hemagglutination associated with full length B. pertus sis FHA, and inhibit adherence of B. bronchisepitca to canine fibroblasts b y as much as 65%. This information may have implications for the developmen t of safe and efficacious subunit vaccines for the prevention of canine bor detellosis and may contribute to future acellular whooping cough vaccines. (C) 1999 Elsevier Science Ltd. Ail rights reserved.