title: Galactose to ceramide linkage is essential for the binding of a polyclonal antibody to galactosyl ceramide.
abstract: Characterization of a polyclonal antibody to galactosyl ceramide (Gal-Cer) which inhibits the internalization and infection of HIV-1 in neural cell lines was carried out. Polyclonal antibody to Gal-Cer was produced by injecting rabbits with Gal-Cer liposomes. The specificity of anti-Gal-Cer binding was studied by high performance thin layer chromatography (HPTLC)-based immunoassay. Using natural and semisynthetic lipids, the specificity of anti-Gal-Cer interaction was studied. The antibody bound to Gal-Cer and its derivatives. The antibody did not bind to glucosyl ceramide or lactosyl ceramide. Glucosyl ceramide differs from Gal-Cer by a hydroxyl group at the fourth carbon and in lactosyl ceramide galactose is linked to ceramide by an intervening glucose molecule. This indicates that D-galactose linked to ceramide is essential for binding. Removal of fatty acid from Gal-Cer, as seen with N-palmitoyl- and N-oleoyl Gal-Cer, had no effect on the binding. It appears that the third carbon of Gal-Cer is not involved in the binding. This is supported by the binding of anti-Gal-Cer to sulfatide or GM4 in which sulfate or sialic acid are added at the third carbon of Gal-Cer, respectively.
authors.affiliation: Department of Neurology, University of Pennsylvania Medical Center, Philadelphia 19104.
authors.forename: S
authors.initials: S
authors.lastname: Bhat
mesh_terms: D000163:Acquired Immunodeficiency Syndrome / Q000517:prevention & control; D000818:Animals; D000906:Antibodies / Q000276:immunology*; D000918:Antibody Specificity; D000937:Antigen-Antibody Reactions / Q000187:drug effects; D001666:Binding Sites, Antibody; D001921:Brain / Q000378:metabolism; D002851:Chromatography, High Pressure Liquid; D005455:Fluorescent Antibody Technique; D005697:Galactosides / Q000494:pharmacology; D005699:Galactosylceramides / Q000276:immunology*; D005963:Glucosylceramides / Q000276:immunology; D015497:HIV-1 / Q000472:pathogenicity; D006801:Humans; D007790:Lactosylceramides / Q000276:immunology; D050356:Lipid Metabolism; D008055:Lipids / Q000302:isolation & purification; D008081:Liposomes / Q000494:pharmacology; D008757:Methylglucosides / Q000494:pharmacology; D009836:Oligodendroglia / Q000378:metabolism; D051381:Rats; D013433:Sulfoglycosphingolipids / Q000378:metabolism
chemical_list: D000906:Antibodies; D005697:Galactosides; D005699:Galactosylceramides; D005963:Glucosylceramides; D007790:Lactosylceramides; D008055:Lipids; D008081:Liposomes; D008757:Methylglucosides; D013433:Sulfoglycosphingolipids; C027020:methylglucoside