Characteristics of some High Molecular Weight Constituents with Bacterial Aggregating Activity from Whole Saliva and Dental Plaque

Abstract

The aim of this study was to investigate the nature of a factor present in human whole saliva which causes the aggregation of certain oral bacteria. It seemed possible that the factor causing aggregation could play a part in plaque formation in that it could promote adhesion of organisms to the teeth and contribute to the mutual adhesion of the organisms in the plaque. Agarose column chromatography of human whole saliva gave a void volume peak which contained the aggregating activity. Investigation of this material showed it to contain 33% protein, 19% anthrone positive carbohydrate, 2.9% N-acetyl neuraminic acid and substantial amounts of hexosamine. Data from ultracentrifugal analysis, agarose column chromatography, amino acid analysis, isoelectric focusing and cetyl trimethylammonium bromide fractionation indicated that the active material was a high molecular weight glycoprotein which exists in solution in a random coil configuration. It was further found that the active material was selectively adsorbed on to the hydroxy-apatite surface and also that a component with properties similar to those described above could be isolated from dental plaque. It seems, therefore, that there is, in whole saliva, a high molecular weight glycoprotein, which selectively adsorbs on to the apatite surface and which causes aggregation of certain oral organisms. It seems possible that this component plays a significant role in the initial selective adhesion of certain oral organisms to the tooth surface, as well as being involved in the mutual adhesion of the organisms in the developing plaque.

Characterization of a Salivary Agglutinin Reacting with a Serotype c Strain of Streptococcus mutans

“…Similar results have been obtained using Bio-Gel A 150 (Bio-Rad) [23] and Bio-Gel A 15 [24]. Ericson et al [5] showed that the agglutinating material from parotid saliva subjected to electrophoresis did not enter a 7.5 'x polyacrylamide gel and that the agglutinin sedimented at 75 000 x g for 90 min.…”

“…In the present study the native agglutinin did not even enter a 2 % polyacrylamide gel and the sedimentation coefficient of I10 S indicates a molecular weight of 10'. Hay et al [23] reported a sedimentation coefficient of 13 S for their agglutinating material. This value seems low.…”

Saliva-Bacterium Interactions in Oral Microbial Ecology

“…Early studies indicated that salivary mucins interact with influenza virus (Oemrawsingh and Roukema, 1974), which was correlated with the sialic acid content of the mucin. Gibbons and co-workers were among the first to describe a salivary bacterial agglutinin (Gibbons and Spinell, 1970), found to be highmolecular-weight, blood group-reactive sialoglycoproteins (Hay et al, 1971). Similar substances were extracted from dental plaque, suggesting a role for this material in plaque formation.…”

“…Evidence that salivary components agglutinate bacteria is afforded by numerous in vitro studies (Ellen et al, 1983;Ericson et al, 1976;Gibbons and Spinell, 1970;Hay et al, 1971; Kashket and Donaldson, 1972;Rosan et al, 1982;Rundegren, 1986). It is assumed that by mediating agglutination, saliva "gathers up" unattached bacteria to foster their clearance from the oral cavity by swallowing.…”

The Nature of Secretory Agglutinins and Aggregating Factors

“…These EDTA-sensitive factors are also distinguished from 1 IS IgA by their large molecular size [Hay et al, 1971;Lachmann and Thompson, 1970] be tween 60S and 90S [Eggert, 1977[Eggert, , 1979a.…”