Functional interaction of Escherichia coli heat-labile enterotoxin with blood group A-active glycoconjugates from differentiated HT29 cells

ESTELA M. GALVAN; GERMAN A. ROTH; CLARA G. MONFERRAN

WILEY-BLACKWELL PUBLISHING, INC

Año: 2006 vol. 273 p. 3444 - 3444

uman colon adenocarcinoma cells (HT29-ATCC) and the clone HT29-5F7 were cultured under conditions that differentiate cells to a polarizedintestinal phenotype. Differentiated cells showed the presence of junctional complexes and intercellular lumina bordered by microvilli. Intestinal brush border hydrolase activities (sucrase, aminopeptidase N, lactase and maltase) were detected mainly in differentiated HT29-ATCC cells compared with the differentiated clone, HT29-5F7. The presence of non-GM1 receptors of Escherichia coli heat-labile enterotoxin (LT-I) on both types of differentiated HT29 cells was indicated by the inability of cholera toxin B subunit to block LT-I binding to the cells. Binding of LT-I to cells, when GM1 was blocked by the cholera toxin B subunit, was characterized by an increased number of LT-I receptors with respect to undifferentiated control cells. Moreover, both types of differentiated cells accumulated higher amounts of cyclic AMP in response to LT-I than undiffer