The use of an immunoperoxidase technique to investigate by light and electron microscopy the sites of binding of Clostridium welchii type-D epsilon toxin in mice.

Mice were given an intravenous dose of formalinised C. welchii type-D epsilon prototoxin and an immunoperoxidase technique was used to demonstrate this antigen in the tissues. The antigen was found to bind to the luminal surface of the endothelial lining of certain blood vessels, to the luminal surface of the cells lining the loops of Henlé and distal convoluted tubules in the kidney, and to the hepatic sinusoids. As it has been shown previously that formalinised epsilon prototoxin and epsilon toxin can compete for the same receptor sites it is postulated that the binding sites demonstrated represent the location of the receptors for C. welchii type-D epsilon toxin.