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ARS Home » Southeast Area » New Orleans, Louisiana » Southern Regional Research Center » Food Processing and Sensory Quality Research » Research » Publications at this Location » Publication #318819

Research Project: Primary and Secondary Prevention of Peanut and Tree Nut Allergy

Location: Food Processing and Sensory Quality Research

Title: The epitopes that cause cross-reactions between peanuts and tree nuts

Author
item Maleki, Soheila
item Bublin, Merima - Medical University Of Veinna
item Chruszcz, Maksymilian - University Of South Carolina
item Grimm, Casey
item Hurlburt, Barry
item Cheng, Hsiaopo
item Breiteneder, Heimo - Medical University Of Veinna
item Schein, Catherine - University Of Texas Medical Branch

Submitted to: European Academy of Allergy and Clinical Immunology
Publication Type: Abstract Only
Publication Acceptance Date: 3/2/2015
Publication Date: 6/16/2015
Citation: Maleki, S.J., Bublin, M., Chruszcz, M., Grimm, C.C., Hurlburt, B.K., Cheng, H., Breiteneder, H., Schein, C. 2015. The epitopes that cause cross-reactions between peanuts and tree nuts. European Academy of Allergy and Clinical Immunology. 135(2):AB32.

Interpretive Summary: Many peanut allergic individuals also have allergies to tree nuts. Our previous work has shown that a computer software, named the Structural Database of Allergenic Proteins (SDAP) can identify similar IgE binding areas that may be important for cross-reactivity between nut proteins or allergens. Based on previous SDAP findings we determined that repeated amino acid sequence areas that were very similar, but not identical, in sequence can be predicted by SDAP. These repeats seem to be common to many different allergenic proteins from nuts and seeds. The presence of highly cross reactive repeat peptide areas are confirmed by our research and may be mainly responsible for clinically symptomatic reactions or cross-reactivity between peanuts and tree nuts. We have produce antibodies against these sequences that inhibit allergic individuals antibodies from binding to the repeat sequences identified here.

Technical Abstract: Many peanut allergic individuals also have allergies to tree nuts. Our previous work has shown that there are epitopes with different amino acid sequences, but similar physical and chemical properties are recognized by the same IgE molecule. Anti-Ara h 2 monoclonal antibodies were produced. They were epitope mapped and the binding sites shown by molecular modeling. Western blots were used to test the binding of these monoclonals to almond, cashew, peanut, pistachio, soy, green pea and walnut extracts and to purified Jug r 2 leader sequence, Jug r 1 and Ara h 2 and Ara h 6. Proteins in the reactive bands were identified by mass spectrometry. These monoclonal antibodies were tested for their ability to compete with IgE for binding to Ara h 2 by ELISA and histamine release assays. Searching the Structural Database for Allergic Proteins (SDAP) and empirical determination of the cross-reactive allergens in different nuts, revealed many potential IgE epitopes with similar physicochemical properties in nut allergens. Specific, anti-Ara h 2 monoclonal antibodies, made against surface exposed areas of native Ara h 2 recognized vicillins, conglutinins, and glycinins in multiple nuts. Four of the monoclonals were highly reactive with Jug r 2 leader sequence, and all recognized Jug r 1. Most of the monoclonals competed for IgE binding to Ara h 2 and prevented histamine release by Ara h 2 to different extents. The presence of highly cross reactive, repeat peptide motifs is confirmed here and we produced monoclonal antibodies that inhibit IgE binding to these sequences.