[Binding of Actinomyces viscosus to collagen]

The ability of collagen adsorbed on apatitic surfaces to promote adhesion of A. viscosus was studied. Treatment of hydroxyapatite (HA) with human type I or type III collagen strongly promoted adhesion of A. viscosus LY7. TEM observations revealed that A. viscosus also attached to fibrils prepared from human type I collagen. The alpha(2) polypeptide derived from type I collagen exhibited moderate activity in promoting binding. Mutans of A. viscosus which possess type I fimbriae, but not type 2 fimbriae or no fimbriae, also bound to collagen-treated HA. This suggests that the adhesin responsible was associated with type I fimbriae, strains of A. israelii and A. odontolyticus also exhibited strong binding to collagen-treated HA. The avidity of Actinomyces species for collagen would seem to be partially responsible for the high proportions of these organisms found on root surfaces.