Structural and functional characterization of protective antibodies induced in peanut oral immunotherapy

食物过敏影响多达10%的美国人口，花生是最常见的食物之一 过敏原，通常导致持续的IgE介导的食物过敏。只有一部分食物过敏患者 在口服免疫治疗(OIT)后出现临床耐受性，而大多数只有短暂的好处。我们和 另一些研究表明，抗花生过敏原的血清免疫球蛋白抗体能抑制嗜碱性粒细胞的激活，这是一种 OIT耐受性的生物标志物。为了阐明OIT的长期耐受机制，我们还需要 了解这些花生特异性免疫球蛋白抗体如何在克隆水平上对临床保护做出贡献。 我们开发基于抗体的治疗IgE介导的食物过敏的新疗法的长期目标取决于 关于阐明OIT诱导长期耐受的抗体介导的潜在机制。在.期间 花生特异性免疫球蛋白抗体可被诱导，并能抑制效应细胞，如肥大细胞或嗜碱性粒细胞。 在体外，这些抗体可以通过阻止IgE被激活来阻止过敏原效应细胞的激活 由过敏原交叉连接，并与抑制性受体结合。我们之前的工作集中在ara h 2上，这是 大多数免疫显性和临床相关的花生过敏原。在这项研究中，对arah2抑制刺激 嗜碱性细胞是耐受性的生物标志物，而Arah2特异性免疫球蛋白的浓度不是。因此，我们 假设OIT后的耐受是由于诱导了唯一具有保护性的免疫球蛋白克隆而不是 过敏原特异性免疫球蛋白普遍升高。这些保护性抗体有效地阻止了IgE介导的 反应。 基于这些发现，我们假设保护性抗体具有独特的结构 这些特性使它们能够以竞争性的适合性与Ara h 2的关键表位结合，并且该表位- 特定的保护性抗体可以从功能上抑制来自不同患者的过敏原特异性IgE。我们的 该方法涉及使用从从中国分离的单一抗原特异性B细胞克隆的重组抗体 OIT后有或无耐受性的个体。我们处于进行这项研究的独特地位，因为我们有 在抗原特异性B细胞的亲和选择、重组抗体克隆和抗体方面的专业知识 来自一个独特的患者队列的特征。我们将在以下具体目标中阐述我们的假设：(1) 确定保护性过敏原特异性免疫球蛋白抗体在耐受性中的arah2结合特征；以及(2) 识别耐受性中的功能性抑制性变应原特异性抗体。 我们预计，拟议的研究将阐明长期临床试验与 OIT在具有保护性抗体的克隆水平上的有效性，突出了特定克隆在 授予对食物过敏的长期耐受性。这项工作将导致食品处理的新战略。 过敏。

Food allergy affects up to 10% of the US population, and peanut is one of the most common food allergens, often leading to persistent IgE-mediated food allergy. Only a subset of patients with food allergy develop clinical tolerance after oral immunotherapy (OIT), while most only have transient benefit. We and others have shown that serum IgG antibodies to peanut allergens suppress basophil activation, which is a biomarker of tolerance in OIT. In order to elucidate the mechanisms of long-term tolerance in OIT, we still need to understand how these peanut-specific IgG antibodies contribute to clinical protection on a clonal level. Our long-term goal to develop new antibody-based treatments for IgE-mediated food allergies depend on elucidating the underlying antibody-mediated mechanism of long-term tolerance induced by OIT. During OIT, peanut-specific IgG antibodies are induced and can inhibit effector cells, such as mast cells or basophils. in vitro, these IgG antibodies can prevent allergen effector cell activation by both blocking IgE from being cross-linked by allergen and binding to inhibitory receptors. Our previous work focused on Ara h 2, which is the most immunodominant and clinically relevant peanut allergen. In that study, suppression of Ara h 2 stimulated basophils was a biomarker of tolerance while the concentration of Ara h 2 specific IgG, was not. Therefore, we hypothesize that tolerance after OIT results from the induction of uniquely protective IgG clones rather than the general increase in allergen-specific IgG. These protective antibodies effectively prevent IgE-mediated reactions. Based on these findings, we hypothesize that protective antibodies share unique structural characteristics that allow them to bind to critical epitopes of Ara h 2 with competitive fitness and that epitope- specific protective antibodies can functionally suppress allergen-specific IgE from a diverse set of patients. Our approach involves using recombinant antibodies cloned from single antigen-specific B cells isolated from individuals with or without tolerance after OIT. We are uniquely positioned to conduct this study in that we have expertise in affinity-selection of antigen-specific B cells, recombinant antibody cloning, and antibody characterization from a unique patient cohort. We will address our hypothesis in the following specific aims: (1) Define Ara h 2 binding characteristics of protective allergen-specific IgG antibodies in tolerance; and (2) Identify functionally suppressive allergen-specific IgG antibodies in tolerance. We anticipate that the proposed studies will elucidate the connection between long-lasting clinical efficacy of OIT on a clonal level with protective antibodies, highlighting the critical role of specific clones in conferring long-term tolerance in food allergy. This work will lead to new strategies for the treatment of food allergies.