expression, purification and characterization of three overlapping immunodominant recombinant fragments from bordetella pertussis filamentous hemagglutinin

background: filamentous hemagglutinin (fha) is one of the most important immunoprotective antigens of bordetella pertussis (b.pertussis) and a major component of the acellular pertussis vaccine. in the present study, three overlapping recombinant fragments from the immunodominant region of fha were produced and their immunogenicity was investigated. methods: three overlapping coding sequences of fha antigen were amplified from b.pertussis genomic dna by pcr. amplified fragments were expressed in escherichia coli (e. coli) bl21(de3) strain and purified through his-tag using nickel-based chromatography. purified fragments were characterized by sds-page and western blotting techniques. in vitro peripheral blood mononuclear cells (pbmc) proliferation and ifn-γ production were assessed in a limited number of healthy adults vaccinated with a commercial acellular pertussis vaccine in response to all purified fha fragments by h3-thymidine incorporation and elisa, respectively. results: recombinant fha segments were successfully cloned and produced at high levels in e. coli bl21(de3). sds-page and western blot analyses confirmed their purity and reactivity. all three recombinant fragments together with a commercial native fha were able to induce in vitro pbmc proliferation and ifn-γ production. conclusion: our preliminary results suggest that these overlapping recombinant fha fragments are immunogenic and may prove to be immuno-protective.