Actinomyces adsorption mediated by type-1 fimbriae.

Area of Science:

• Oral microbiology
• Bacterial adhesion
• Immunology

Background:

• Actinomyces viscosus and Actinomyces naeslundii are oral bacteria implicated in dental plaque formation.
• Bacterial adhesion to tooth surfaces is a critical initial step in colonization and biofilm development.
• The role of specific bacterial structures, such as fimbriae, in mediating this adhesion is an area of active research.

Purpose of the Study:

• To investigate the role of type-1 fimbriae in the adherence of Actinomyces viscosus and Actinomyces naeslundii to saliva-treated hydroxyapatite.
• To determine if type-1 fimbriae function as the primary adhesin for these oral bacteria.

Main Methods:

• Production and use of a monospecific antibody targeting type-1 fimbriae of Actinomyces viscosus T14V.
• Testing the antibody's reactivity against various serotypes of A. viscosus and A. naeslundii.
• Assessing the adherence of bacterial strains to saliva-treated hydroxyapatite.
• Evaluating the inhibitory effect of the monospecific antibody on bacterial adherence.

Main Results:

• The monospecific antibody reacted with serotype 2 strains of A. viscosus and serotype 2 or 3 strains of A. naeslundii, but not with serotype 1 A. naeslundii.
• Bacterial strains positive for the type-1 fimbrial antigen demonstrated strong adherence to saliva-treated hydroxyapatite.
• Inhibition of adherence was observed in a significant proportion (18 of 24 strains) when the monospecific antibody was present.

Conclusions:

• The presence of type-1 fimbriae is strongly correlated with the ability of Actinomyces strains to adhere to tooth surfaces.
• Type-1 fimbriae are identified as the principal adhesin mediating the interaction between these bacteria and the tooth surface.
• This finding has implications for understanding early dental plaque formation and potential therapeutic targets.