Question: I have a nut allergy and it has always been a liability throughout my life. Any innocent looking pastry or dessert can send me to the hospital, without warning. I have always wondered what happens at the molecular level that causes my symptoms. In this work I hope to develop a deeper understanding of the biochemical reactions that result from nut allergens.

Answer: Fundamentally, allergies are caused by an over reactive immune system. The most common allergies are to pollen and food – in rarer cases medications and trace metals can act as allergens. The beginning of almost every allergic reaction involves the binding of an allergen to an IgE (Immunoglobin E) antibody. This bound complex between the allergen and antibody is located on the membrane of Mast cells. These Mast cells, primed with antibody, cause the release of many potent chemicals such as histamine. Such molecules are responsible for the inflammation response in addition to other cascades that cause one to feel ill. Histamine is directly responsible for anaphylaxis (severe allergic reaction) through its interaction with the histamine H1 receptor. With regards to peanut allergies, 13 different allergens within peanuts have been identified. The most commonly identified are Ara h 1, Ara h 2, and Ara h 3. Ara h 1, and h 2 are both glycoproteins; glycoproteins are proteins that also have sugar groups attached. More than 95% of US citizens with peanut allergies have a specific IgE that interacts with Ara h 2. There are many mechanisms proposed to reduce the allergenicity of peanuts including radiation, chemical, and biological methods. These seem to show great promise but a key issue with removing/destroying the allergens in peanuts is that these allergens comprise roughly 30% of the protein in peanuts. Thus peanuts treated with these techniques may not taste like peanuts. Another technique still being researched that avoids this issue is to block the Ara h 2 binding site on IgE antibodies using competitive inhibition.

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  • Zeus the Sitar Lord

Sources:

  1. Yang Zhou, Jin-shui Wang, Xiao-jia Yang, et al., “Peanut Allergy, Allergen Composition, and Methods of Reducing Allergenicity: A Review,” International Journal of Food Science, vol. 2013, Article ID 909140, 8 pages, 2013. doi:10.1155/2013/909140
  2. White MV. The role of histamine in allergic diseases. J Allergy Clin Immunol. 1990;86(4 Pt 2):599-605.
  3. Schmitt DA, Cheng H, Maleki SJ, Burks AW. Competitive inhibition ELISA for quantification of Ara h 1 and Ara h 2, the major allergens of peanuts. J AOAC Int. 2004;87(6):1492-7.
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