The conformational epitope of Ara h 5 was crucial to the severe reactivity of peanut allergy

Abstract

Conformational epitopes are associated with the development of food allergic tolerance and the severity of food allergy. Peanut can trigger severe anaphylactic reactions, however, the reason behind the severe allergic reactions caused by peanut remains unexplained. The purpose of this article was to provide an explanation for the severe allergy caused by peanut, focusing on the conformational epitopes of Ara h 5 and Ara h 8 allergens that exhibit cross-reactivity with asthma reactions. Ara h 5 and Ara h 8 proteins were prepared by an Escherichia coli expression system. IgE reactivity of 37 patients with allergy toward Ara h 5 and Ara h 8 allergens was assessed by using IgE-binding assays, dot blot and western blot. The allergenicity of Ara h 5 and Ara h 8 protein was analysed in mouse model. Conformational IgE epitopes of Ara h 5 was identified using phage peptide library and the Pepitope Server. Compared to Ara h 8, the conformational epitope of Ara h 5 protein was crucial in the process of sensitization. Ara h 5 showed a stronger IgE reactivity and the ability to induce β-hexosaminidase release. Ara h 5 caused more severe lung inflammation than Ara h 8 protein. While Ara h 8 caused more severe intestinal inflammation than Ara h 5. The results showed that the conformational epitope sequences of Ara h 5 were WETIYSR and FHWWYLK. The results provide a theoretical basis for the production of hypoallergenic peanut protein and the immunotherapy of peanut allergy.