title: Structural variations of blood group A antigens in human normal colon and carcinomas.
abstract: The blood group A determinant is carried by four basic carrier carbohydrate chains. This paper reports the expression of blood group A variants, as determined by immunohistology with highly specific monoclonal anti-A antibodies, in 18 adenocarcinomas of the distal colon, 4 specimens of normal proximal mucosa from group A persons, and 5 specimens of fetal colonic mucosa. Monoclonal antibodies directed to type 1 chain A, type 1 chain ALeb, type 2 chain A, type 2 chain ALey, and type 3 chain A (repetitive A) were used. In normal mucosa, type 1 chain A and ALeb were expressed in proximal regions. Type 1 chain A was expressed in columnar cells, whereas type 1 chain ALeb was found in goblet cells. Type 2 and type 3 chain A structures were not found in normal adult mucosa. All types of A antigens were detected in adenocarcinomas from the distal colon as well as in normal fetal mucosa. In fetal mucosa, type 1 chain A and ALeb antigens and type 3 chain A antigens were expressed in columnar cells, whereas type 2 chain A and Ley and type 1 chain ALeb antigens were found in goblet cells. The results indicate that blood group A antigens with type 1, 2, and 3 carriers are present in fetal mucosa and adenocarcinomas of distal colon, while epithelial mucosa of normal adult colon is characterized by the exclusive expression of type 1 chain A antigens.
mesh_terms: D000017:ABO Blood-Group System; D000368:Aged; D002241:Carbohydrates / Q000032:analysis; D003106:Colon / Q000276:immunology*; D003110:Colonic Neoplasms / Q000097:blood*; D000939:Epitopes / Q000032:analysis; D005260:Female; D005333:Fetus / Q000276:immunology; D006801:Humans; D008297:Male; D008875:Middle Aged
chemical_list: D000017:ABO Blood-Group System; D002241:Carbohydrates; D000939:Epitopes