1996 The Pathological Society of Great Britain and Ireland BACTERIAL PATHOGENICITY

Fimbriae have been demonstrated on strains of Bordetella pertussis that possess agglutinogen 2 (types 1,2,3 and 1,2), but not on those that lack it (types 1,3 and 1). This correlation between fimbriation and the presence of agglutinogen 2 has been found with fresh isolatds from children and with laboratory strains that are virulent for mice. If fimbriae enhance the attachment of bacteria to mucosal cells, these find’ings offer an explanation for the predominance of serotypes 1,2,3 and 1,2 in non-vaccinated communities. The findings also suggest that agglutinogen 3 is not a fimbrial antigen, and because this is an essential component of fully effective whole-cell vaccine, a subcellular vaccine prepared from fimbriae alone may be inadequate.