QUANTIFYING THE STRENGTH OF BACTERIAL ADHESIVE INTERACTIONS WITH SALIVARY GLYCOPROTEINS

We adapted an assay that has been used to estimate the strength of euk aryotic cell-cell and cell-extracellular matrix adhesive interactions (McClay et al., 1981) to quantify the strength of bacterial (streptoco cci, fusobacteria, actinomyces) interactions with salivary receptors. Bacteria are centrifuged onto human submandibular/sublingual or paroti d-saliva-coated microtiter wells. Plates are sealed with pressure-sens itive, double-sided tape which allows them to be inverted and centrifu ged again. The force required to remove the bacteria from the coated w ells is a direct measure of the adhesive strength of the interaction(s ) being disrupted. The bacteria-saliva adhesive forces we detected ran ged from 1.6 x 10(-8) dynes (Streptococcus sanguis 72-40) to > 1.1 x 1 0(-7) dynes (Actinomyces viscosus T14 V). These forces were in the ran ge to withstand the shear stress produced by salivary flow, which we c alculated as approximately 6.1 x 10(-7) dynes.