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>A 23 kDa membrane glycoprotein bearing NeuNAcα2-3Galβ1-3GalNAc O-linked carbohydrate chains acts as a receptor forStreptococcus sanguisOMZ 9 on human buccal epithelial cells
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A 23 kDa membrane glycoprotein bearing NeuNAcα2-3Galβ1-3GalNAc O-linked carbohydrate chains acts as a receptor forStreptococcus sanguisOMZ 9 on human buccal epithelial cells
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机译：A 23 kDa membrane glycoprotein bearing NeuNAcα2-3Galβ1-3GalNAc O-linked carbohydrate chains acts as a receptor forStreptococcus sanguisOMZ 9 on human buccal epithelial cells
Streptococcus sanguiscolonizes several human oral surfaces, including both hard and soft tissues. Large salivary mucin like glycoproteins bearing sialic acid residues are known to bind variousS.sanguisstrains. However, the molecular basis for the adhesion ofS.sanguisto human buccal epithelial cells (HBEC) has not been established. The present study shows thatS.sanguisOMZ 9 binds to exfoliated HBEC in a sialic acid-sensitive manner. The desialylation of such cells invariably abolhhes adhesion ofS.sanguisOMZ 9 to the cell surface. A soluble glycopeptide bearing short sialylated O-linked carbohydrate chains behaves as a potent inhibitor of the attachment ofS.sanguisOMZ 9 to exfoliated HBEC. The resialylation of desialylated HBEC with CMP-sialic acid and Galβ1,3GalNAcα2,3-sialyltransferase specific forO-glycans restores the receptor function forS.sanguisOMZ 9, whereas a similar cell resialylation with the Galβ1,4GlcNAcα2,6-sialyltmnsferase specific forN-glycans is without effect. Finally, ceinyl-sialic acid as a substrate yeilds exfoliated HBFC bearing flurescence as the catalyst. The latter finding demonstrates that this 23kDa cell surface glycoprotein bears NeuNAcα2-3Galβ1-3GalNAc O-linked sugar chains, a carbohydrate sequence which is recongnized byS.sanguisOMZ 9 on exfoliated HBEC. In similar experiments carried out with a buccal carcinoma cell line termed SqCC/Y1S.sanguisOMZ 9 did not attach in great numbers to such cultured cells, and these cells were shown to not express membrane glycoprotien bearingα2,3-sialylated O-linked carbohydrate
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