Vicilin allergens of peanut and tree nuts (walnut, hazelnut and cashew nut) share structurally related IgE-binding epitopes.

Surface-exposed IgE-binding epitopes of close overall conformation were characterized on the molecular surface of three-dimensional models built for the vicilin allergens of peanut (Ara h 1), walnut (Jug r 2), hazelnut (Cor a 11) and cashew nut (Ana o 1). They correspond to linear stretches of conserved amino acid sequences mainly located along the C-terminus of the polypeptide chains. A glyco-epitope corresponding to an exposed N-glycosylation site could also interfere with the IgE-binding epitopes. All these epitopic regions should participate in the IgE-binding cross-reactivity commonly reported between tree nuts or between peanut and some tree nuts in sensitized individuals. Owing to this epitopic community which constitutes a risk of cross-sensitization, the avoidance or a restricted consumption of other tree nuts should be recommended to peanut-sensitized individuals.