[Cholestyramine adsorbs Escherichia coli and Vibrio cholerae toxins by way of ion exchange mechanism].

The use of cholestyramine in the treatment of enterocolitis is justified by its ability to fix the LT toxin of Vibrio cholerae and ETEC, the ST toxin of ETEC and the verotoxin of EHEC at the pH of intestinal fluid. To elucidate the nature of the ion-exchange mechanism in the binding of the toxins on the resin, we try to eluate the toxins with 0.1 M to 0.9 M NaCl solution at pH 7. Irrespective of their presence or absence in the different fractions, the biological activity of the toxins was assessed in cell culture and in the new-born mouse test. Desorption of the LT toxin from Vibrio cholerae is obtained with 0.6 M to 0.8 M of NaCl, with 0.3 M to 0.5 M of NaCl for the LT, 0.4 M to 0.5 M for the VT and 0.6 M for the TS toxins. The eluated toxins are biologically active; these facts demonstrate that the adsorption of toxin on cholestyramine result of a ion-exchange mechanism.