Role of hyaluronidase in immediate hypersensitivity reaction

Hyaluronidase (Hydase) activity in 48-hr homologous passive cutaneous anaphylaxis (PCA) increased about one and one-half times the control for 5 min after challenge with antigen, then gradually decreased and disappeared after 30 min. Change in Hydase activity correlated well with the increase in capillary permeability by PCA. DSCG and BPS given intravenously 10 min prior to challenge produced increases in capillary permeability and Hydase activity caused by PCA was inhibited. Chlorpheniramine inhibited the increase of the capillary permeability, but not the acceleration of Hydase. Prednisolone neither affected the capillary permeability nor the Hydase activity. Similar results were also obtained in in vitro studies. An increase in the capillary permeability caused by PCA, histamine, or 5-HT was additionally augmented by Hydase. Thus, Hydase appears to be involved in the increase in the capillary permeability caused by an immediate hypersensitivity reaction.