Characterization of glycoconjugates of human gastrointestinal mucosa by lectins. I. Histochemical distribution of lectin binding sites in normal alimentary tract as well as in benign and malignant gastric neoplasms.

Abstract

Labeled lectins with binding specificity to the hexose components of mucus glycoproteins (HPA, RCA I, PNA, Con A, WGA, and UEA I) were used to demonstrate structural differences in the glycoprotein composition of various cell types of the normal, benign and malignant gastrointestinal mucosa. While in the RCA I, UEA I, and WGA binding of normal mucus secreting cell types only quantitative differences were observed, the mucus in the surface epithelial cells of gastric mucosa and in the colonic goblet cells was characterized by the absence of PNA, Con A, and PNA, HPA binding sites, respectively. These lectins, however, showed a strong binding to the supranuclear, Golgi-region in the undifferentiated or activated forms of these cells. Even the staining intensity of the luminal membrane surfaces of the non mucinous parietal and chief cells was often stronger by PNA, HPA, and RCA I lectins than that of the mucus secretions in the highly differentiated mucus cells. These results indicate the existence of either heterogeneous glycoprotein components or mucus molecules with variations in the degree of glycosylation of their oligosaccharide chains in the different cells. The latter seems more likely since in benign and malignant alterations lectin binding sites appear in great density, which were found to be characteristic of the undifferentiated mucus cells or for the non mucinous cells of the normal gastric mucosa. Similarly in some gastric cancers which do not stain with the periodic acid-Schiff reaction at all, large amount of free or neuraminic acid substituted PNA binding sites can be detected.

Lectin Binding Pattern of Gastric Mucosa of Pacific White-Sided Dolphin, Lagenorhynchus obliquidens

“…The lectins, including GSL-II selectively labelled the luminal surface. Similar staining patterns have been observed in human, bovine, and rat stomachs [4,10,13,16,27]. At the apical region, chief cells have abundant zymogen granules, and thus the luminal membrane surface displays a positive reaction to lectins.…”

“…The different staining patterns of lectins between them are possible to be result from the different kind of secretion between them. The same staining pattern has been observed in human, rat, Japanese macaque, domestic cat, and camel stomachs [2][3][4]23]. In some animals, the bottom portion contains neutral, acidic sulphated, and acidic carboxylated mucins [23].…”

Ultracytochemistry of glycosylation sites of rat colonic mucous cells with labeled lectins.

“…The sequence of sugar residues from each mucous glycoprotein is destined genetically and is modified by the microenvironment of the cells that constitute each organ (7,9,29).…”

Transcytosis ofListeria monocytogenesacross the intestinal barrier upon specific targeting of goblet cell accessible E-cadherin

“…To determine the cell subtypes that express accessible hEcad, we costained intestinal villi for luminally accessible hEcad and wheat germ agglutinin (WGA). WGA specifically binds to sialic acid and N-acetylglucosaminyl carbohydrate residues present on the plasma membrane of enterocytes and in mucus of GCs (Fischer et al, 1984;Jang et al, 2004 We observed that hEcad is luminally accessible at the tip of villi ( Fig. 2 B, arrow; see other examples in Fig.…”