Efficacy of mechanisms to modify the allergenicity of peanuts and tree nuts.

摘要

About 2-3% of adults in the United States are food allergic. Allergic reactions to foods can be serious and life-threatening. We undertook studies to explore mechanisms to reduce the allergenicity of tree nuts and peanuts. Three approaches were used including: (1) study of the natural variation in the expression of walnut allergens in 63 cultivars, (2) the effect of temperature, pressure, and processing on allergen stability, structure, and potency, and (3) a mouse model to determine the role of walnut and peanut polyphenolic compounds in sensitization to a model allergen, chicken egg ovalbumin. No hypoallergenic walnut cultivars were identified. The major walnut allergens could be found in all cultivars tested and serum IgE from individuals with walnut allergy bound proteins in all cultivars tested. Temperature and pressure treatment had little effect on the allergens in peanuts. However, a processing method that combined boiling and frying did decrease the presence of soluble Ara h 1 and Ara h 2, two major peanut allergens, as well as Ara h 6, a minor peanut allergen. This decrease in allergenic proteins did not translate into a decreased allergenic potency of those peanuts as peanut extracts from boiled/fried peanuts were able to activate basophils loaded with serum IgE from peanut-allergic individuals. Finally, we have shown that i.p. co-administration of walnut polyphenolic extract with ovalbumin in the presence of aluminum hydroxide gel adjuvant increases serum OV-specific IgE and IgG1 levels, without increasing serum OV-specific IgG2a/2b levels above those seen in OV/AL controls. Further research is required to determine if boiled/fried peanuts and/or polyphenolic-depleted walnuts reduce levels of sensitization in genetically predisposed individuals.