Allergy, Asthma and Immunology: Structure and function of the peanut panallergen Ara h 8

+Author Affiliations

¹ Agricultural Research Service, United States;
² University of South Carolina, United States;
³ University of Virginia, United States

↵* Corresponding author; email: barry.hurlburt@ars.usda.gov

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Background: Ara_h_8 is hypothesized to be responsible for cross-reactivity between birch pollen and peanut.

Results: The Ara_h_8 crystal structure is very similar to Bet_v_1 from birch and it has similar ligand-binding function.

Conclusion: Ara_h_8 is most likely responsible for cross-reactivity between birch pollen and peanut.

Significance: A structural and functional understanding of cross-reactivity between Bet_v_1 and Ara_h_8 was obtained.

Abstract

SUMMARY The incidence of peanut allergy continues to rise in the US and Europe. Whereas exposure to the major allergens Ara h 1, 2, 3, and 6 can cause fatal anaphylaxis, exposure to the minor allergens usually does not. Ara h 8 is a minor allergen. Importantly, it is the minor food allergens that are thought to be responsible for Oral Allergy Syndrome (OAS) in which sensitization to airborne allergens causes a Type 2 allergic reaction to ingested foods. Furthermore, it is believed that similar protein structure, rather than a similar linear sequence is the cause of OAS. Bet v 1 from birch pollen is a common sensitizing agent and OAS results when patients consume certain fruits, vegetables, tree nuts and peanuts. Here, we report the 3-dimensional structure of Ara h 8, a Bet v 1 homolog. The overall fold is very similar to that of Bet v 1, Api g 1 (celery), Gly m 4 (soy) and Pru av 1 (cherry). Ara h 8 binds the isoflavones quercetin and apigenin, as well as resveratrol avidly.

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