Enzyme-Potentiated Hyposensitisation

Abstract

The ability of preparations of hyaluronidase and <i>β</i>-glucuronidase to potentiate the hyposensitising effect of small doses of antigen injected subcutaneously into previously sensitised animals has been investigated in three different models of experimental anaphylaxis. Guinea-pigs were sensitised by egg albumen and repeatedly challenged by exposure to an aerosol of the antigen at weekly intervals. A small dose of antigen by injection increased their pre-convulsion times on subsequent challenge, and this was potentiated by the addition of hyaluronidase and <i>β</i>-glucuronidase. Rats were sensitised by horse serum and challenged 18 days later with intravenous antigen, deaths being noted within 24 h. Ten days after sensitisation, subcutaneous injections of antigen and <i>β</i>-glucuronidase greatly reduced the mortality on subsequent challenge although antigen injected alone had no effect. In mice sensitised by horse serum and challenged by pinnal anaphylaxis, the anamnestic increase in sensitivity produced by a subcutaneous dose of antigen was prevented by <i>β</i>-glucuronidase. Using this model, tolerance was induced by the intravenous injection of antigen and this was prevented by the addition of hyaluronidase.