alpha GalNAc is essential for recognition of Exo-1 epithelial antigen by mouse monoclonal antibody Pa-G-14.
Mouse monoclonal antibody Pa-G-14 detects Exo-1, an antigen whose expression is regulated in the processes of epithelial-cell differentiation and transformation. The epitope recognized by Pa-G-14 is present both in glycosphingolipids and in mucin glycoproteins. To characterize the specificity of Pa-G-14, immuno-thin-layer chromatography, biochemical, and enzymatic treatment of glycosphingolipid extracts from human pancreas were used. The antibody bound to all blood-group-A substances; alpha GalNAc, but not fucose, was essential for reactivity. In ELISA, Pa-G-14 also reacted with ovine and bovine submaxillary mucins but not with porcine submaxillary mucin. Binding to ovine submaxillary mucin was resistant to neuraminidase treatment. In solid-phase absorption assays on synthetic carbohydrate structures, Pa-G-14 recognized broadly blood group A, Tn and sialyl-Tn. Using immuno-electron-microscopic techniques, reactivity with all Golgi cisternae and mucin droplets of mucous cells in ovine submaxillary gland was demonstrated. All these assays indicate that Pa-G-14 shows a novel specificity, since it binds blood group A, Tn and sialyl-Tn, the common structural feature of these epitopes being the presence of a terminal alpha GalNAc sugar unit.
Schröder
H
H
Departament d'Immunologia, Universitat Autònoma de Barcelona, Spain.
Francí
C
C
Egea
G
G
Oriol
R
R
Klingel
R
R
Dippold
W G
WG
Real
F X
FX
D000116:Acetylgalactosamine / Q000276:immunology*; D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology*; D000918:Antibody Specificity; D000951:Antigens, Neoplasm / Q000737:chemistry / Q000276:immunology*; D000954:Antigens, Surface / Q000737:chemistry / Q000276:immunology*; D002240:Carbohydrate Sequence; D002417:Cattle; D000939:Epitopes / Q000032:analysis / Q000737:chemistry / Q000276:immunology; D006023:Glycoproteins / Q000276:immunology; D006028:Glycosphingolipids / Q000276:immunology; D006801:Humans; D051379:Mice; D008969:Molecular Sequence Data; D009077:Mucins / Q000276:immunology; D010179:Pancreas / Q000737:chemistry; D012756:Sheep; D013363:Submandibular Gland / Q000276:immunology / Q000648:ultrastructure
D000911:Antibodies, Monoclonal; D000951:Antigens, Neoplasm; D000954:Antigens, Surface; D000939:Epitopes; D006023:Glycoproteins; D006028:Glycosphingolipids; D009077:Mucins; D000116:Acetylgalactosamine