Immunohistochemical localization of beta-1,4-galactosyltransferase in human pancreatic tissues

beta-1,4-Galactosyltransferase (GalTase) is the glycosyltransferase in the Golgi apparatus that transfers galactose from UDP-galactose to terminal N-a cetylglucosamine residues in glycoconjugates with formation of a beta-1,4 l inkage. Neoplasms undergo various changes in the carbohydrate moieties of t heir glycoconjugates. This process also indicates the possibility of change s in glycosyltransferases themselves. Therefore, we compared the binding pa ttern of a monoclonal antibody (MAb8628) against GalTase in both normal and neoplastic exocrine pancreatic tissues. Ten normal and 11 neoplastic human exocrine pancreatic tissues obtained from surgery were used. Frozen sectio ns were incubated with this antibody. Supranuclear regions and terminal bar s of normal duct cells and acinar cells revealed positive staining for GalT ase at the light microscopic level. Centroacinar cells revealed positive st aining in their perinuclear region. Neoplastic cells were also stained in t heir supranuclear regions and terminal bars. Supranuclear regions were well developed in neoplastic cells and intensely stained compared with those in normal cells. The supranuclear regions and the terminal bars corresponded to the trans cisternae of the Golgi apparatus and the junctional complex (i .e., tight junction and adherens junction), respectively, seen at the elect ron microscopic level. Pancreatic neoplastic changes thus led to an increas e in the expression of GalTase in the Golgi apparatus, the increase of whic h may have an important effect on the intercellular adhesion and communicat ion among pancreatic epithelial cells. Measurement of this enzyme is useful for diagnosis of exocrine pancreatic neoplastic changes from normal tissue s.