FUCOSYLATED THOMSEN-FRIEDENREICH ANTIGEN IN ALPHA-ANOMERIC CONFIGURATION IN HUMAN GASTRIC SURFACE EPITHELIA - AN ALLOGENEIC CARBOHYDRATE ANTIGEN POSSIBLY CONTROLLED BY THE SE GENE

Human gastric surface epithelial cells display the ABH blood group ant igens with the core structure of N-acetyllactosamine (NAcLc). Their ex pression is under the control of the secretor gene Se. The Thomsen-Fri edenreich (T)-antigen (Gal beta 1-3GalNAc-) is another core structure of the ABH antigens. We examined the gastric surface epithelial expres sion of T- and alpha 1-2 fucosylated T (FucT) histochemically with pea nut agglutinin (PNA) and monoclonal antibody (MAb) MBr1, respectively. Eight of 24 individuals exhibited the PNA-reactive antigen (i.e., T-e xpressers) and others the MBr1-reactive antigen (i.e., FucT-expressers ). alpha-L-fucosidase digestion of the FucT-positive tissues and beta- galactosidase digestion of the T-positive tissues, respectively, made them reactive with PNA and the antibody specific for GalNAc alpha-O-Se r/Thr. There was a remarkable correlation among reactivities with MBr1 , Ulex europaeus lectin 1 (UEA1), and anti-Le(b) MAb CO-431. ABH blood group status had no correlation with this expression. We conclude tha t human gastric surface epithelial cells constitutionally synthesize T in alpha configuration (i.e., Gal beta 1-3GalNAc alpha-O-Ser/Thr) and that it was alpha 1-2 fucosylated only in the FucT-expressers. alpha 1-2 fucosylation of T is suggested to be regulated by the Se gene.