Purification of a functional receptor for Clostridium difficile toxin A from intestinal brush border membranes of...

A receptor for Clostridium difficile toxin A was purified from brush border membranes (BBMs) from the small intestine of infant hamsters. The BBMs were solubilized with Triton X-114, and the solubilized receptor was purified with use of a toxin A immobilized affinity-chromatography column and differential temperature elution. SDS-PAGE and silver staining of the purified receptor revealed numerous high-molecular-weight bands. However, ligand blotting analysis with 125I-toxin A used as the probe identified a 163-kD protein as the predominate toxin A-binding molecule. Toxin A bound to the purified receptor at physiological temperature, but the amount of toxin bound increased at lower temperatures. Bovine thyroglobulin bound to toxin A and inhibited its binding to the purified receptor. Preincubation of the receptor with lectins produced by Bandeirea simplicifolia or Datura stramonium reduced specific binding by 125I-toxin A. Our data indicate that the purified toxin A receptor from small intestine BBMs of infant hamsters is a galactose- and N-acetylglucosamine-containing glycoprotein.