Temporal lectin histochemical characterization of porcine small intestine

A variety of biotinylated lectins was applied to formalin-fixed intestinal sections from isolator-reared pigs ranging in age from newborn through 12 weeks. Lectin binding to brush borders of villus enterocytes, crypt enterocytes, and dome epithelium, and lectin reactivity within goblet cells and Brunner's glands was semiquantified by microscopy and was used to estimate temporal changes in complex carbohydrates of enteric epithelium. Although variability in binding scores often was observed among pigs of the same age, several general patterns of lectin binding were detected. Dolichos biflorus and Ulex europaeus lectins had increasing binding to brush border membranes as pigs aged. The Dolichos biflorus, however, had decreased binding at the 12-week time point. Neuraminidase-treated Arachis hypogaea and Triticum vulgaris were associated with high mean binding scores at all time points. Canavalia ensiformis bound, with high mean score at all time points, to villus but not to crypt enterocytes. Arachis hypogaea was associated with variable but often high binding scores, regardless of pig age. Succinylated wheat germ agglutinin bound more to crypt than to villus enterocytes. Goblet cells were generally less reactive than were corresponding villi and crypts. Dome epithelium reactivity varied with the lectin used, whereas Brunner's glands reacted with all lectins tested. We conclude that age and regional variations in lectin binding may reflect differences in intestinal function and differentiation. Because complex carbohydrates may act as cell surface receptors for a variety of enteric pathogens, our results indicate that these differences may be partially responsible for age and anatomic differences in susceptibility or resistance to enteric disease.