Reduction of allergenicity of irradiated ovalbumin in ovalbumin-allergic mice

摘要

Egg allergy is one of the most serious of the immediate hypersensitivity reactions to foods.Such an allergic disorder is mediated by IgE antibodies stimulated by T-helper type 2(Th2)lymphocytes.This study was undertaken to evaluate changes of allergenicity and cytokine profiles by exposure of irradiated ovalbumin(OVA),a major allergen of egg white,in the OVA-allergic mice model.OVA solutions(2mg/ml in 0.01 M phosphate buffered saline(PBS)were gamma-irradiated to 50 and 100kGy.The allergenicity in the OVA-allergy-induced mice model was remarkably reduced when challenged with irradiated OVA.Cultures of spleen cells harvested from OVA-sensitized mice showed a significant decrease in Th2 cytokine levels of ILs-4 and-5 with a concomitant increase in Th1 cytokine levels of IL-12 when co-cultured with irradiated OVA.However,IFN-gamma level decreased dependant on the radiation dose of co-cultured OVA.The levels of IgEs and Th2-cytokine were reduced dependant on the radiation dose.These data show that the irradiated OVA could downregulate the activity of Th2 lymphocytes in OVA-sensitized mice.