Mapping the Critical Epitopes of Ara h 2 and Ara h 6

描述（由申请人提供）：食物过敏是工业化国家的一个世界性问题，其患病率似乎正在增加，影响约1%的美国人口。IgE介导的食物反应，特别是花生，是医院外发生过敏反应的最常见原因。避免花生，推荐的方法，是不够的，由于频繁的意外摄入。有许多新兴的实验性疗法，但这些都有局限性。虽然我们对IgE如何与花生过敏原结合有很多了解，但对这些过敏原如何交联IgE/IgE受体复合物（IgE/FceRI）以激活肥大细胞和嗜碱性粒细胞知之甚少。该提案将利用我们小组的三项重要调查结果：1）相关和互补的2S白蛋白，Ara h 2和Ara h 6，是最有效的花生过敏原，2）IgE与两个特异性线性表位的结合（每个过敏原上一个）与更严重的临床病史相关，和3）重组Ara h 6在巴斯德毕赤酵母中表达，但不在大肠杆菌中表达，具有完整的效应子活性，使其成为理解效应子功能的分子基础的稳健模型。在所提出的研究中，我们将测量患者来源的IgE与Ara h 2和Ara h 6的特异性线性表位在三个重要临床环境中的结合：临床反应性的自然史、患者对临床指示的花生四烯酸的反应以及患者对口服免疫疗法（OIT）的反应。我们将使用这些数据来确定在这些临床环境中与Ara h 2和Ara h 6肽具有确定结合模式的相对风险。然后，我们将确定特定的氨基酸的阿糖胞苷h 6，然后阿糖胞苷h 2是关键的有效交联的IgE/Fc？RI.最后，我们将开发兔多克隆抗体，鼠单克隆抗体，和人的scFv片段作为潜在的抑制剂的阿糖胞苷h 2和阿糖胞苷h 6介导的IgE/Fc的交联？RI.这些也将用作新的诊断试剂。通过完成这些具体目标，我们将克服理解过敏原如何与IgE相互作用以交联IgE/FceRI复合物的重大障碍，并将该领域推向开发用于评估和治疗花生过敏的新诊断和治疗工具。本研究的未来方向是充分开发这些工具并将其应用于临床实践。

DESCRIPTION (provided by applicant): Hypersensitivity to foods is a world-wide problem in the industrialized world and its prevalence appears to be increasing, affecting approximately 1% of the US population. IgE-mediated reactions to foods, particularly peanuts, are the most common cause of anaphylaxis occurring outside of the hospital. Avoidance of peanuts, the recommended approach, is inadequate due to frequent accidental ingestion. There are a number of emerging experimental therapies but these all have limitations. Although we understand a great deal about how IgE binds to peanut allergens, little is known about how these allergens cross-link IgE/IgE receptor complexes (IgE/FceRI) to activate mast cells and basophils. This proposal will capitalize on three significant findings from our group: 1) the related and complementary 2S albumins, Ara h 2 and Ara h 6, are the most potent peanut allergens, 2) binding of IgE to two specific linear epitopes (one on each allergen) is associated with more severe clinical histories and 3) recombinant Ara h 6 expressed in Pichia pastoris, but not in Escherichia coli, has full effector activity making this a robust model for understanding th molecular basis of effector function. In the proposed studies we will measure binding of patient-derived IgE to specific linear epitopes of Ara h 2 and Ara h 6 in three important clinical settings natural history of clinical reactivity, response of patients to clinically indicated peanut challenes, and response of patients to oral immunotherapy (OIT). We will use these data to determine the relative risk of having defined binding patterns to peptides of Ara h 2 and Ara h 6 in each of these clinical settings. We will then determine the specific amino acids of Ara h 6 and then Ara h 2 that are critical for effective cross-linking of IgE/Fc?RI. Finally we will develop rabbit polyclnal antibodies, murine monoclonal antibodies, and human scFv fragments as potential inhibitors of Ara h 2 and Ara h 6 - mediated cross-linking of IgE/Fc?RI. These will also be useful as novel diagnostic reagents. By completing these specific aims we will overcome the significant obstacle of understanding how allergens interact with IgE to cross-link IgE/FceRI complexes and will move the field forward towards development of new diagnostic and therapeutic tools for the evaluation and treatment of peanut allergy. The future direction of this research is to fully develop these tools and bring them to clinical practice.