6'-Sulfo sialyl Lex but not 6-sulfo sialyl Lex expressed on the cell surface supports L-selectin-mediated adhesion.

In order to determine if a sulfated oligosaccharide on the cell surface can function as an L-selectin ligand, a novel approach for in vitro transfer of oligosaccharides was utilized (Srivastava, G., Kaun, K. J., Hindsgaul, O., and Palcic, M. M. (1992) J. Biol. Chem. 267, 22356-22361). CHO cells were incubated with synthetic 6'-sulfo sialyl Lex, NeuNAcalpha2-->3(sulfate-6)Galbeta1-->4(Fucalpha1-->3) GlcNAc or 6-sulfo sialyl Lex, NeuNAcalpha2-->3Galbeta1-->4[(Fucalpha1-->3)sulfate--> 6GlcNAc] oligosaccharide linked to C-6 of a fucose residue in GDP-fucose and a milk fucosyltransferase. The resultant CHO cells expressing 6'-sulfo sialyl Lex or 6-sulfo sialyl Lex on their cell surface were tested for adhesion to E-selectin and L-selectin chimeric proteins coated on plates. The results indicate that 6'-sulfo sialyl Lex supports L-selectin-mediated adhesion much better than sialyl Lex similarly tagged on the cell surface. In contrast, 6-sulfo sialyl Lex containing a sulfate group on the N-acetylglucosamine residue did not support adhesion with either selectin. These combined results suggest that 6'-sulfo sialyl Lex is a much better ligand than sialyl Lex oligosaccharide for L-selectin.