6'-SULFO SIALYL LE(X) BUT NOT 6-SULFO SIALYL LE(X) EXPRESSED ON THE CELL-SURFACE SUPPORTS L-SELECTIN-MEDIATED ADHESION

In order to determine if a sulfated oligosaccharide on the cell surfac e 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, 22356-22 361). CHO cells were incubated with synthetic 6'-sulfo sialyl Le(x), N euNAc alpha 2-->3(sulfate-6)Gal beta 1-->4(Fuc alpha 1-->3)GlcNAc or 6 -sulfo sialyl Le(x), NeuNAc alpha 2-->3Gal beta 1-->4[(Fuc-alpha 1-->3 )sulfate-->6GlcNAc] oligosaccharide linked to C-6 of a fucose residue in GDP-fucose and a milk fucosyltransferase, The resultant CHO cells e xpressing 6'-sulfo sialyl Le(x) or 6-sulfo sialyl Le(x) 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 Le(x) supports L-selectin-mediated adhesion much better than sialyl Le (x) similarly tagged on the cell surface, In contrast, 6 sulfo sialyl Le(x) containing a sulfate group on the N-acetylglucosamine residue di d not support adhesion with either selectin, These combined results su ggest that 6'-sulfo sialyl Lex is a much better ligand than sialyl Le( x) oligosaccharide for L-selectin.