A 23 kDa membrane glycoprotein bearing NeuNAcα2-3Galβ1-3GalNAc O-linked carbohydrate chains acts as a receptor for Streptococcus sanguis OMZ 9 on human buccal epithelial cells

Abstract

Streptococcus sanguis colonizes several human oral surfaces, including both hard and soft tissues. Large salivary mucin-like glycoproteins bearing sialic acid residues are known to bind various S.sanguis strains. However, the molecular basis for the adhesion of S.sanguis to human buccal epithelial cells (HBEC) has not been established. The present study shows that S.sanguis OMZ 9 binds to exfoliated HBEC in a sialic acid-sensitive manner. The desialylation of such cells invariably abolishes adhesion of S.sanguis OMZ 9 to the cell surface. A soluble glycopeptide bearing short sialylated O-linked carbohydrate chains behaves as a potent inhibitor of the attachment of S.sanguis OMZ 9 to exfoliated HBEC. The resialylation of desialylated HBEC with CMP-sialic acid and Gal beta 1,3GalNAc alpha 2,3-sialyltransferase specific for O-glycans restores the receptor function for S.sanguis OMZ 9, whereas a similar cell resialylation with the Gal beta 1,4GlcNAc alpha 2,6-sialyltransferase specific for N-glycans is without effect. Finally, the same resialylation reaction carried out with CMP-9-fluoresceinyl-sialic acid as a substrate yields exfoliated HBEC bearing fluorescence on a single 23 kDa protein, when using the alpha 2,3-sialyltransferase as the catalyst. The latter finding demonstrates that this 23 kDa cell surface glycoprotein bears NeuNAc alpha 2-3Gal beta 1-3GalNAc O-linked sugar chains, a carbohydrate sequence which is recognized by S.sanguis OMZ 9 on exfoliated HBEC. In similar experiments carried out with a buccal carcinoma cell line termed SqCC/Y1, S.sanguis OMZ 9 did not attach in great numbers to such cultured cells, and these cells were shown to not express membrane glycoprotein bearing alpha 2,3-sialylated O-linked carbohydrate chains.

The Streptococcus gordonii Surface Proteins GspB and Hsa Mediate Binding to Sialylated Carbohydrate Epitopes on the Platelet Membrane Glycoprotein Ibα

“…In that study, the interaction was localized to the amino-terminal portion of GPIb␣ (amino acids 1 to 225), suggesting that the epitopes on GPIb to which S. sanguis and S. gordonii adhere may be different. In a separate report, the O-linked trisaccharide NeuAc␣(2-3)Gal␤(1-3)GalNAc has been defined as a receptor for S. sanguis OMZ 9 on buccal epithelial cells (16). It would be interesting to determine whether S. sanguis OMZ 9 can also bind GPIb␣ and whether binding by these S. sanguis strains is mediated by a homologue of GspB and Hsa.…”

Immunomodulatory peptides obtained by the enzymatic hydrolysis of whey proteins

“…GMP also exhibits various antimicrobial and relatedactivities, including inhibiting influenza virus hemagglutination (Kawasaki et al, 1993), inhibiting the binding of cholera toxin (CT) and E. coli enterotoxins (Isoda et al, 1999Isoda, Kawasaki, Tanimoto, Dosako, & Idota, 1999Kawasaki et al, 1992;Neeser, Chambaz, Hoang, & LinkAmster, 1988) and inhibiting the growth of E. coli and various oral pathogens (Malkoski et al, 2001;Neeser, Chambaz, Del Vedovo, Prigent, & Guggenheim, 1988;Neeser et al, 1994Neeser et al, , 1995. In addition, Malkoski et al (2001) demonstrated that hydrolyzing GMP with endoproteinase Glu-C released various peptides, of which Ser (P) 149 k-casein f138-158 exhibited growth-inhibitory activity against Streptococcus mutans.…”

Powdered Milk Micellar Casein Prevents Oral Colonization by <i>Streptococcus sobrinus</i> and Dental Caries in Rats: A Basis for the Caries–Protective Effect of Dairy Products

“…We showed that soluble caseinate and casein-derived glyco-and phosphopeptides behaved in vitro as potent inhibitors of Streptococcus sobrinus OMZ 176 adhesion to saliva-coated hydroxyapatite beads, whereas such molecules were not able to inhibit the attachment of Actinomyces viscosus Ny1 [Neeser et al, 1994]. Caseinoglycomacropeptide was also able to specifically prevent the adhesion in vitro of Streptococcus sanguis OMZ 9 to human buccal epithelial cells [Neeser et al, 1995], and casein-derived glyco-and phosphopeptides were observed to incorporate into the salivary pellicle inhibiting the adhesion of mutans streptococci [Schüpbach et al, 1996]. Thus, whilst the possible modulation of the oral microbiota by milk casein and/or some of its subcomponents has been documented, the in vivo significance remained to be investigated.…”