Acquisition of P-selectin Binding Activity by en Bloc Transfer of Sulfo Lex Trisaccharide to the Cell Surface: Comparison to a Sialyl Lex Tetrasaccharide Transferred on the Cell Surface

Sialyl Lex, NeuNAcα2 → 3Galβ1 → 4(Fucα1 → 3)GlcNAcβ → R, is known to be a ligand for E-selectin in various assays. The sulfated counterpart of sialyl Lex, sulfo Lex, (Sulfo → 3) Galβ1 → 4 (Fucα1 → 3) GlcNAcβ → R, was also shown to be a ligand for E-selectin in solid-phase assays employing immobilized oligosaccharides. In order to determine whether sulfo Lex structure on the cell surface also works as E-selectin or P-selectin ligand, a novel approach for in vitro transfer of oligosaccharides (S. Tsuboi, Y. Isogai, N. Hada, J. K. King, O. Hindsgaul, and M. Fukuda (1996) J. Biol. Chem. 271, 27213–27216) was utilized. A synthetic GDP-fucose harboring sialyl Lex or sulfo Lex oligosaccharide was enzymatically transferred to Chinese hamster ovary (CHO) cells with a milk fucosyltransferase. The resultant cells, CHO-sialyl Lex and CHO-sulfo Lex were tested for adhesion to E-selectin · IgG or P-selectin · IgG chimeric protein coated on plates. The results indicate that CHO-sialyl Lex adhered efficiently to E-selectin, while adhesion of CHO-sulfo Lex was very poor despite the fact that near equal number of the ligands had been attached to the cell surface. In contrast, CHO-sulfo Lex adhered efficiently to P-selectin, while CHO-sialyl Lex adhered modestly to P-selectin. These results demonstrate that sialyl Lex and sulfo Lex structures on the cell surface differ substantially in their ability to adhere to E- and P-selectin.