AN IGG MONOCLONAL-ANTIBODY AGAINST DICTYOSTELIUM-DISCOIDEUM GLYCOPROTEINS SPECIFICALLY RECOGNIZES FUC-ALPHA-1,6GLCNAC-BETA IN THE CORE OF N-LINKED GLYCANS - LOCALIZED EXPRESSION OF CORE-FUCOSYLATED GLYCOCONJUGATES IN HUMAN TISSUES

Core fucosylation of N-linked oligosaccharides (GlcNAc beta 1,4(Fuc al pha 1,6)GlcNAc beta 1-Asn) is a common modification in animal glycans, but little is known about the distribution of core-fucosylated glycop roteins in mammalian tissues, Two monoclonal antibodies, CAB2 and CAB4 , previously raised against carbohydrate epitopes of Dictyostelium dis coideum glycoproteins (Crandall, I, E, and Newell, P, C, (1989) Develo pment 107, 87-94), specifically recognize fucose residues in alpha 1,6 -linkage to the asparagine-bound GlcNAc of N-linked oligosaccharides. These IgG3 antibodies do not cross-react with glycoproteins containing alpha-fucoses in other linkages commonly seen in N- or O-linked sugar chains, CAB4 recognizes core alpha 1,6 fucose regardless of terminal sugars, branching pattern, sialic acid linkage, or polylactosamine sub stitution, This contrasts to lentil and pea lectins that recognize a s imilar epitope in only a subset of these structures, Additional GlcNAc residues found in the core of N-glycans from dominant Chinese hamster ovary cell mutants LEC14 and LEC18 progressively decrease binding, Th ese antibodies show that many proteins in human tissues are core-fucos ylated, but their expression is localized to skin keratinocytes, vascu lar and visceral smooth muscle cells, epithelia, and some extracellula r matrix-like material surrounding subpopulations of lymphocytes. The availability of these antibodies now allows for an extended investigat ion of; core fucose epitope expression in development and malignancy a nd in genetically manipulated mice.