Bordetella pertussis fimbrial protein 2 and Bordetella pertussis fimbrial protein 3 (Fim2 and Fim3)

Fimbrial proteins 2 and 3 are major filamentous surface proteins of Bordetella pertussis, assembled as long, helical, hair-like appendages (fimbriae) that mediate critical adherence to the ciliated epithelial cells of the respiratory tract, biofilm development, and immune evasion[1][3][5][7]. Each fimbria consists mostly of either Fim2 or Fim3 pilin subunits, whose genes (*fim2* and *fim3*) are distinct but homologous[3][5]. These proteins are essential for bacterial virulence and are key targets of the immune response as well as components of most modern acellular pertussis vaccines, where anti-fimbrial antibodies help prevent infection by inhibiting bacterial colonization[1][5][7]. Fim2 and Fim3 differ slightly in sequence, serological properties, and functional effects on biofilm formation and immune interactions[1][3][4]. Genetic variation in these loci helps diversify circulating B. pertussis strains and is useful for molecular surveillance and typing[4][5].

Other names

Fim2Fim3Type 2 fimbriaeType 3 fimbriaeBordetella pertussis fimbriaeSerotype 2 fimbriaeSerotype 3 fimbriae

Induced antibody response: Vaccination with Fim2/Fim3-containing vaccines generates antibodies that bind these antigens, blocking bacterial adhesion to the respiratory mucosa and thus preventing colonization and disease