Adhesion of K88ab fimbriated E. coli in piglet small intestines in relation with iron transport molecules

Enteropathogenic K88 fimbricated E. coli colonize the piglet small intestine. In swine, it has been previously established that some pigs lack intestinal receptors for K88 lectins and that these animals are resistant to infections by K88-positive E. coli. The receptor is inherited as a simple mendelian character. The interactions established between the glycoconjugate receptors of pig brush borders and K88 lectins are mediated by O- and N-linked glycoproteins which differ between adhesive and non-adhesive piglets. In this study the adhesion of E. coli K88+ in crossbred F2 (LW x MS) x (LW x MS) populations. By using in vitro brush border test, we observed modulation of the adhesion of K88 fimbriae and distinguished high and low affinity receptors. Furthermore, we correlated the attachment with glycoprotein pattern of epithelial cells and mucus. Epithelial cells and mucus contained several glycopeptides (from 42 to 74 kDa) recognized by K88ab fimbriae. The 74 kDa glycoprotein was characteristic of adhesive phenotype and was a mucosal transferrin (iTf). It appeared that iTf was more abundant in adhesive intestines than in non-adhesive ones, suggesting that susceptibility/resistance phenotype could be related to iron metabolism in the intestinal tract. Furthermore, we visualized the intestinal transferrin receptors on the brush border membrane of epithelial cells, probably implicated in iron absorption.