Repulsive contribution of surface sialic acid residues to cell adhesion to substratum

Roles of surface sialic acid residues in cell adhesion to substratum were investigated in model systems to clarify their contribution to intercellular interactions. Treatment of cells of a fibroblastic cell line, Swiss 3T3, an epithelial cell line, TES-1, and a T lymphoma cell line, BW5147, with a sialylated oligosaccharide binding lectin enhanced adhesion to plastic plates irrespective of the cell lineage. This enhancement was inhibited by the addition of sialyl lactose. Digestion of the cells with sialidase or endoglycoceramidase also augmented adhesion. On the other hand, adhesion was reduced by pre-coating plastic plates with gangliosides but not with desialylated gangliosides. These findings suggest that sialic acid residues exposed to cell surfaces negatively regulate cell adhesiveness.