Changes in Allergenicity of Ovalbumin and on Conjugation with Quercetin.

A previous study demonstrated decreased allergenicity of some food allergens after conjugation with polyphenols. However, little is known about how polyphenol conjugation with food allergens affects allergenicity. We conjugated a well-known food allergen, ovalbumin (OVA), with quercetin (QUE) to assess the potential allergenicity of OVA and in a BALB/c mouse model. QUE could covalently conjugate with OVA and changed the protein structure, which might destroy and/or mask OVA epitopes. Conjugation with QUE decreased IgE binding properties and the release capacity of the conjugated OVA. , as compared with native protein, conjugation with QUE decreased the levels of IgE, IgG1, IgG, plasma histamine, and mast cell protease-1 (mMCP-1) on the surface of sensitized mast cells, along with decreased FcεRI and c-kit expression. The levels of Th2-related cytokines (IL-4, IL-5, IL-13) decreased and that of a Th1-related cytokine (IFN-γ) increased slightly, which suggests that conjugation with QUE modulated the imbalance of the Th1/Th2 immune response. Conjugation of OVA with QUE could reduce OVA allergenicity and , which could provide information for reducing food allergenicity by conjugation with polyphenols.