EXCEED THE SPACE PROVIDED. Allergic reactions to peanuts occur because susceptible individuals respond to exposure to peanuts by producing a plasma protein, IgE, that binds to a high affinity receptor, FcERI, on mast cells and basophils. This IgE can be cross-linked by specific allergens leading to activation of mast cells and basophils and subsequent allergic reactions. Three major peanut allergens have been described in detail based on their ability to bind IgE on Western blots and to interact with IgE in RAST-inhibition assays. These are Ara hl, Ara h2, and Ara h3. The degree to which these allergens contribute functionally to the activity in crude peanut extracts has never been documented. We propose to use in vitro funcitonal assays to better define the major peanut allergens and will test our in vitro findings in vivo using a mouse model of peanut allergy. Our preliminary data suggests that most of our patients with hypersensitivity to peanuts react to Ara h2 at a 2 log or better sensitivity than to Ara hl. As part of this proposal, these observations will be correlated with independent analysis of these sera on immunoblot. We have further assessed the reactivity of our patients to Ara hl and Ara h2 by quantitating the reactivity to purified proteins and comparing that reactivity to the reactivity with crude peanut extracts. Based on our preliminary data, neither Ara hl nor Ara h2 appear to be major functional allergens in 6 of 7 patients we have examined, whereas Ara h2 may be of great importance in one of seven patients. In a preliminary study, we have separated peanut proteins by anion exchange chromatography and find that a significant portion of the functional allergic activity chromatographs in fractions that do not contain Ara hl or Ara h2. The contents of these fractions is unknown but will be analyzed by functional assays, 2d gels, mass spectroscopy, and IgE immunoblotting. Therefore, we propose to combine functional assays with standard immunoblotting techinques and the power of proteomics to define in molecular detail the peanut allergens quantitatively responsible for mast cell activation in patients with systemic reactions to peanuts. Employment of this approach to define novel, functional major allergens has the potential to completely change our thinking as to which peanut allergens are the most important in specific patients for allergic reactions. PERFORMANCE SITE ========================================Section End===========================================

Agency
National Institute of Health (NIH)
Institute
National Institute of Allergy and Infectious Diseases (NIAID)
Type
Research Project (R01)
Project #
5R01AI052164-03
Application #
6841150
Study Section
Immunological Sciences Study Section (IMS)
Program Officer
Plaut, Marshall
Project Start
2003-07-01
Project End
2006-12-31
Budget Start
2005-01-01
Budget End
2006-12-31
Support Year
3
Fiscal Year
2005
Total Cost
$308,000
Indirect Cost
Name
University of Colorado Denver
Department
Internal Medicine/Medicine
Type
Schools of Medicine
DUNS #
041096314
City
Aurora
State
CO
Country
United States
Zip Code
80045
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Bernard, Hervé; Guillon, Blanche; Drumare, Marie-Françoise et al. (2015) Allergenicity of peanut component Ara h 2: Contribution of conformational versus linear hydroxyproline-containing epitopes. J Allergy Clin Immunol 135:1267-74.e1-8
Otsu, K; Guo, R; Dreskin, S C (2015) Epitope analysis of Ara h 2 and Ara h 6: characteristic patterns of IgE-binding fingerprints among individuals with similar clinical histories. Clin Exp Allergy 45:471-84
Koid, Audrey E; Chapman, Martin D; Hamilton, Robert G et al. (2014) Ara h 6 complements Ara h 2 as an important marker for IgE reactivity to peanut. J Agric Food Chem 62:206-13
Mills, K; Lay, J; Wu, W et al. (2014) Vitamin E, ?-tocopherol, diminishes ex vivo basophil response to dust mite allergen. Allergy 69:541-4
Chen, Xueni; Wang, Qian; El-Mezayen, Rabab et al. (2013) Ara h 2 and Ara h 6 have similar allergenic activity and are substantially redundant. Int Arch Allergy Immunol 160:251-8
Zhuang, Yonghua; Dreskin, Stephen C (2013) Redefining the major peanut allergens. Immunol Res 55:125-34
Kulis, M; Chen, X; Lew, J et al. (2012) The 2S albumin allergens of Arachis hypogaea, Ara h 2 and Ara h 6, are the major elicitors of anaphylaxis and can effectively desensitize peanut-allergic mice. Clin Exp Allergy 42:326-36
Zhuang, Yonghua; Durrani, Sandy; Hodges, Brittany D M et al. (2012) Expression of recombinant Ara h 6 in Pichia pastoris but not in Escherichia coli preserves allergic effector function and allows assessment of specific mutations. Mol Nutr Food Res 56:986-95
Martucci, Michael A; Dreskin, Stephen C (2011) Immunologic similarities between selected autoimmune diseases and peanut allergy: possible new therapeutic approaches. Curr Allergy Asthma Rep 11:334-9

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