Exploiting and enhancing IgE-binding epitopes of the 2S albumins of peanuts and tree nuts

点击翻译按钮获取中文摘要

Abstract: IgE-mediated food allergy to peanuts (PN) and/or tree nuts (TN), is a major health problem in the United States, affecting approximately 4% of children and up to 2% of adults. Co-allergy among these foods is relatively common and is difficult to identify given the more common finding of co-sensitization. Recent progress with early administration of these foods and oral immunotherapy, especially in conjunction with anti-IgE have merit. Unfortunately, these approaches are not successful for all patients and, even when successful, have limitations regarding compliance and unpredictable breakthrough. There are significant, unmet needs to 1) understand the immunologic details of IgE mediated activation of mast cells by allergens from PN and TN, 2) understand the molecular basis for co-allergy among TN and between PN and TN, 3) develop improved diagnostics to identify clinically relevant peanut and tree nut allergy and 4) design new approaches to interfere with allergic reactions caused by peanuts. The overarching concept of this proposal is that the 2S albumins are the most important allergens of peanuts and tree nuts and are the key to understanding PN and TN allergy and cross-reactivity and to developing potent diagnostic and potentially therapeutic reagents. Preliminary data show that we have 1) developed a sensitive ELISA assay, 2) identified the critical amino acids within IgE-binding peptides, 3) demonstrated that conformationally constrained (3D) peptides bind IgE strongly and 4) shown that patients with PN allergy alone and PN + TN allergy identify different patterns of peptides in a microarray assay. We hypothesize that 1) we can optimize IgE binding to existing peptides and discover novel peptides with enhanced binding, 2) there are cross- reacting epitopes of PN and selected TN and 3) IgE binding to existing and novel peptides will have potential predictive value for important clinical outcomes. We propose to 1) perform positional amino acid (aa) screening to optimize binding of IgE to peptides, 2) utilize click chemistry and stapling technology to enhance IgE binding and resistance to proteases and 3) use microarray technology to assess IgE binding with well-defined samples from patients with PN, WN, PecN, CN and PisN allergy and from those undergoing clinical trials. Success in this project will establish a new intellectual framework regarding allergen/IgE interactions, describe, at least in part, the molecular basis for these co-allergies, design new diagnostics and move us along the path toward development of an oral, peptide based, treatment for peanut allergy.