GLYCOPROTEINS OF HUMAN JEJUNAL CELLS: LOCATION, MATURAT10NAL CHANGES AND INDIVIDUAL VARIATION

Abstract

A battery of 12 lectins conjugated to horseradish peroxidase was used to characterize secretory and cell surface glycoproteins (GP) in secretions from small bowel biopsies of 9 children. The glycoproteins found differed from site to site, among individuals at a given site and from crypt to villar tip. In goblet cells stored secretions showed individual variation in intensity of staining and increasing fucose content from crypt to villus. Terminal N-acetylglucosamine was seen in the Golgi cisternae but not in stored secretion, suggesting capping of this sugar by other residues during GP biosynthesis. Terminal α-N-acetylgalactosamine was present in Golgi cisternae of all and in the stored secretion of two-thirds of the specimens. Immature cryptal columnar cells had fucose-rich GP presumably in secretory granules. Mature villar cells did not. Columnar cells showed mannose-rich GP, presumably lysosomal enzymes, in apical punctate bodies. In some specimens the basolateral plasmalemma of columnar cells stained selectively for fucose and β-galactose. Brush border staining generally paralleled that of goblet cell secretions with similar maturational changes. Staining for terminal galactose highlighted cells, presumably leukocytes, infiltrating the epithelium and lamina propria. The diversity and variability of the GP in human jejunal mucosa suggest a relationship between specific chemical structures and biologic function at the cytologic loci.