Binding of FITC-labelled lectins to the gastrointestinal epithelium of the rat

Biotechnology uses lectin genes to transfect into crop plants for protection against insects and nematodes. On the other hand, the information is limited on lectin-binding properties of cells in the gastrointestinal tract. Therefore, binding of a panel of FITC-labelled plant lectins to gastrointestinal cells of the rat was studied. In the stomach, cytoplasmic staining of parietal cells by PHA appeared to be due to glycoproteins attached to the tubulovesicles. PNA also stained the parietal cells, but only in the isthmus and neck regions, reacting with desialylated glycoproteins. WGA bound to the mucous neck cells with higher affinity than to the surface and foveolar mucous cells. The mucous cells were also stained by SNA-I, UEA-I and, less intensively, by LCA. Chief cells did not show detectable reaction with any of the applied lectins. Binding of PHA to gastric cells showed differences when compared with the results of in vivostudies. Small intestinal brush border was stained with UEA-I and SNA-I, the latter lectin also strongly stained the surface of small intestinal crypts. Both lectins reacted with the mucus of goblet cells. In the large intestine UEA-I and SNA-I stained the goblet cells at the base and upper part of the crypts, respectively. Accordingly, we provided evidences for the unique lectin-binding phenotype of the various segments of the gastrointestinal tract.