Allergens and epitopes involved in food allergy to wheat and their presence in different wheat genotypes

National audienceWheat may trigger different hypersensitive reactions including food allergy to wheat (FAW). In most cases, FAW is an IgE-mediated allergy. In children, FAW frequently induces atopic eczema /dermatitis syndrome. In adults, allergic reactions to wheat are often severe (exercise induced anaphylaxis, chronic urticaria, anaphylaxis). Wheat allergens have been characterized by several in vitro and in vivo techniques (ELISA, Western blotting, cell activation and skin prick tests). They have been identified among albumins/globulins as well as among prolamins. The albumin/globulin fraction contains major allergens for patients suffering from atopic dermatitis. -gliadins and low molecular weight (LMW) glutenin subunits (GS) are dominant allergens for adults developing severe symptoms. Epitope mapping showed that the last group of patients had IgE directed against numerous linear epitopes in repetitive domains of gliadins. The large genetic polymorphism of wheat leads to variations in sequences or contents of some proteins and may influence the allergen content of wheat genotypes. In a previous study, we concentrated on a bread wheat collection representative of European variability at the Gli-B1 locus, where genes coding for 5-gliadins are clustered. We observed that the 1BL/1RS translocation, deleting the Gli-B1 locus, abolished IgE reactivity towards gliadins for most patients with severe symptoms. We then started analysis of old wheat species such as Triticum spelta, Triticum monococcum or Triticum turgidum and observed differences in allergen composition between some of these genotypes and cultivated wheat. These studies allow better characterization of allergenicity of different wheat genotypes and may be used by breeders to reduce allergen content for some individuals