title: Inhibition of reovirus type 3 binding to host cells by sialylated glycoproteins is mediated through the viral attachment protein.
abstract: The interaction of mammalian reoviruses with sialylated glycoproteins was studied and found to be highly serotype specific in that attachment of type 3 Dearing reovirus to murine L cell receptors could be strongly inhibited by bovine submaxillary mucin (BSM), fetuin, and alpha 1 acid glycoprotein, albeit at different efficiencies, whereas attachment of type 1 Lang reovirus was inhibited only by fetuin. We subsequently demonstrated, by using reassortants between type 3 and 1 reoviruses, that inhibition of reovirus attachment to cell receptors was specified by the viral attachment protein gene S1. Using a solid-phase binding assay, we further demonstrated that the ability of reovirus type 3 or reassortant 1HA3 and the inability of reovirus type 1 or reassortant 3HA1 to bind avidly to BSM was a property of the viral S1 genome segment and required the presence of sialic acid residues on BSM oligosaccharides. Taken together, these results demonstrated that there is a serotype-specific difference in the ability of the reovirus attachment protein, sigma 1, to interact with sialylated oligosaccharides of glycoproteins. Interaction of reovirus type 3 with sialylated oligosaccharides of BSM is dramatically affected by the degree of O-acetylation of their sialic acid residues, as indicated by the findings that chemical removal of O-acetyl groups stimulated reovirus type 3 attachment to BSM, whereas preferential removal of residues lacking or possessing reduced amounts of O-acetyl groups per sialic acid molecule with Vibrio cholerae sialidase abolished binding. We also demonstrated that BSM was 10 times more potent in inhibiting attachment of infectious reovirus to L cells than was V. cholerae-treated BSM. The results are consistent with the hypothesis that sialylated oligosaccharides on host cells or erythrocytes may act as binding sites or components of binding sites for type 3 reovirus through a specific interaction with the virus attachment protein.
mesh_terms: D000818:Animals; D001667:Binding, Competitive; D002213:Capsid / Q000378:metabolism*; D036022:Capsid Proteins; D002448:Cell Adhesion; D007739:L Cells; D012089:Mammalian orthoreovirus 3 / Q000378:metabolism*; D051379:Mice; D011991:Receptors, Virus / Q000378:metabolism*; D012087:Reoviridae / Q000378:metabolism*; D012794:Sialic Acids / Q000378:metabolism; D012795:Sialoglycoproteins / Q000378:metabolism*; D013329:Structure-Activity Relationship; D014764:Viral Proteins / Q000378:metabolism*
chemical_list: D036022:Capsid Proteins; D011991:Receptors, Virus; D012794:Sialic Acids; D012795:Sialoglycoproteins; D014764:Viral Proteins; C031728:sigma 1 protein, reovirus