Fucosylated Glycosphingolipids of Human Myeloid Cells

Our efforts to determine the carbohydrate binding specificity of two myeloid-specific monoclonal antibodies (VIM-1 and VIM-10) resulted in the purification of three fucosylated glycosphingolipids from human chronic myelogenous leukemia cells. After repeated high-performance liquid chromatographic separations, two forms of fucosylated glycosphingolipids were resolved. VIM-i and VIM-b were found to bind to the heptaosylceramide Galβ1-4 (Fucα 1-3)GlcNAcβ1-3Galβ1-4GlcNAc,β1-3Galβ1-4Glcβ1-1-Cer with the Lex (Lewis X) epitope, but not to either the hexaosylceramide Fucα1-2Galβ1-4(Fucα1-3)GlcNAcβ1-3Galβ1-4Glcβ1-1-Cer or the octaosylceramide Fucα1-2Galβ1-4(Fucα1-3)GlcNAcα1-3Galβ1-4GlcNAcβ1-3Galβ1-4Glcβ1-1Cer, each with the Ley (Lewis Y) epitope. The latter two glycosphingolipids are the first Ley antigens to be purified from human leukocytes and structurally characterized. Binding studies with a range of glycosphingolipids from myoloid cells and other biological sources demonstrated that VIM-1 and VIM- 10 bind to Ley glycosphingolipids with five or more sugar residues, but not to a glycosphingolipid (III3Fuc-nLc6Cer) with an internal Lex trisaccharide.