TAILIEUCHUNG - Báo cáo khoa học: Functional interaction of Escherichia coli heat-labile enterotoxin with blood group A-active glycoconjugates from differentiated HT29 cells

Human colon adenocarcinoma cells (HT29-ATCC) and the clone HT29-5F7 were cultured under conditions that differentiate cells to a polarized intestinal 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 mal-tase) were detected mainly in differentiated HT29-ATCC cells compared with the differentiated clone, HT29-5F7. | iFEBS Journal Functional interaction of Escherichia coli heat-labile enterotoxin with blood group A-active glycoconjugates from differentiated HT29 cells Estela M. Galvan German A. Roth and Clara G. Monferran Departamento de Química Biológica - CIQUIBIC CONICET Facultad de Ciencias Quimicas Universidad Nacionalde Cordoba Argentina Keywords ABH glycoconjugates differentiated HT29 cells Escherichia coli heat-labile toxin glycosphingolipids toxin receptors Correspondence C. G. Monferran Departamento de Quimica Biologica Facultad de Ciencias Quimicas Universidad Nacionalde Cordoba Ciudad Universitaria Cordoba X5000HUA Argentina Fax 54 351 4334074 Tel 54 351 4334168 4334171 E-mail cmonfe@ Received 1 March 2006 revised 28 April 2006 accepted 22 May 2006 doi Human colon adenocarcinoma cells HT29-ATCC and the clone HT29-5F7 were cultured under conditions that differentiate cells to a polarized intestinal 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 undifferentiated cells. Helix pomatia lectin inhibited the binding of LT-I to cells and the subsequent production of cyclic AMP. LT-I recognized blood group A-active glycosphingolipids as functional .

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