Filamentous haemagglutinin adhesin (FHA) is an important virulence factor from Bordetella pertussis related to the adhesion and spread of the bacteria through the respiratory tract. Filamentous hemagglutinin is a 220 kDa protein associated with the bacterial surface, but also secreted in substantial amounts. Studies using FHA-deficient B. pertussis strains implicate this protein in tracheal colonization, cell adherence, and invasion of macrophages and epithelial cells by B. pertussis. FHA is a useful tool in immunoassays and whooping cough vaccination studies. Description: Bordetella Pertussis. Alternative Names: FHA, Bordetella Pertussis, Purified FHA