Effect of heat denaturation of egg white proteins ovalbumin and ovomucoid on CD4+ T cell cytokine production and human mast cell histamine production

The conformational epitopes of egg glycoproteins ovalbumin (OVA) and ovomucoid (OVM) recognized by IgE antibodies in an allergic response can be denatured at high temperatures. This structural change results in a decreased allergenicity and has earlier been used to induce clinical tolerance for specific oral immunotherapy in allergic patients via consumption of cooked egg products. We investigated the difference in allergic response when consuming heat-treated and native egg proteins by examining the cytokine production of CD4+ T cells and mast cell histamine release. Cultures of mouse CD4+ T cells and dendritic cells were stimulated with native and heat denatured OVA and OVM (HD-OVA and HD-OVM) and various cytokine and histamine concentrations were measured using ELISA. An increased concentration of IL-12, IL-17 and IL-10 and a decreased concentration of IL-4 were detected in both HD-OVA and HD-OVM (p < 0.05). A decreased concentration of histamine was detected in HD-OVM (p < 0.05) with human KU812 basophil like cells. Heat denatured egg proteins OVA and OVM demonstrated a skewed type 1 CD4+ T cell cytokine response and inhibited intracellular Ca2+ concentration. This study provides insights into understanding the mechanisms behind induced tolerance of allergic individuals when consuming cooked egg.