Bile salts promote adherence-decreasing effect of colonic luminal hydrolases on Entamoeba histolytica.

E. histolytica trophozoites cultivated for > 7 h in the presence of glycosidases, produced by a subset of the colonic anaerobic bacteria of healthy humans, and pancreatic proteases show decreased adherence to Chinese hamster ovary epithelial cells. Since activities of the glycosidases are enhanced by bile salts we investigated whether bile salts would enhance the E. histolytica-CHO cell adherence decreasing effects of the luminal hydrolases (glycosidases plus proteases). CHO cell adherence of control trophozoites was 78.4 +/- 1.2% (mean +/- SEM). Incubations with the hydrolases alone for 4 h did not change adherence. Addition of 5.0 mM sodium taurocholate to the hydrolases for 4 h decreased trophozoite adherence to 30.5 +/- 3.2% of that of control trophozoites (p < 0.05). The effect of sodium taurocholate was dose dependent over 0.5-5.0 mM. Four hour incubation with the hydrolases and sodium taurodeoxycholate at 2.0 and 5.0 mM also decreased trophozoite adherence to 25.1 +/- 2.9% and 29.4 +/- 1.7%, respectively, of that of control trophozoites. These findings show that bile salts enhance the effects of luminal hydrolases on E. histolytica trophozoites, decreasing their ability to adhere to epithelial cells.