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

花生口服免疫疗法诱导的保护性抗体的结构和功能表征

基本信息

批准号：
10507767
负责人：
Sarita U Patil
金额：
$ 50.26万
依托单位：
MASSACHUSETTS GENERAL HOSPITAL
依托单位国家：
美国
项目类别：
财政年份：
2020
资助国家：
美国
起止时间：
2020-11-20 至 2025-10-31
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/10507767
关键词：
Address Affect Affinity Allergens Allergic Allergic Reaction Allergy to peanuts Anaphylaxis Antibodies Antibody Binding Sites Antibody Therapy Antigens B-Cell Antigen Receptor B-Lymphocytes Basophils Binding Biological Markers Cell surface Characteristics Clinical Clinical Trials Cloning Data Development Disease Dose Effector Cell Epitopes FDA approved Flow Cytometry Food Hypersensitivity Goals IgE IgG4 Immunoglobulin G In Vitro Individual Life Life Experience Light Mediating Memory B-Lymphocyte Oral Characters Passive Cutaneous Anaphylaxis Patients Population Positioning Attribute Prevalence Public Health Reaction Recombinant Antibody Risk Role Serum Site-Directed Mutagenesis Specificity Supervision Testing Work clinical efficacy clinically relevant cohort crosslink desensitization fitness food allergen in vivo lonely individuals mast cell mouse model novel therapeutic intervention novel therapeutics oral immunotherapy patient subsets prevent receptor response

项目摘要

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.

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，通常会导致持续的 IgE 介导的食物过敏。只有一小部分患者有食物过敏口服免疫疗法（OIT）后产生临床耐受性，但大多数仅具有短暂的益处。我们和其他研究表明，针对花生过敏原的血清 IgG 抗体可抑制嗜碱性粒细胞活化，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，我们仍然需要了解这些花生特异性 IgG 抗体如何在克隆水平上发挥临床保护作用。我们开发新的抗体疗法来治疗 IgE 介导的食物过敏的长期目标取决于阐明 OIT 诱导的长期耐受的潜在抗体介导机制。期间 OIT，花生特异性 IgG 抗体被诱导并可以抑制效应细胞，例如肥大细胞或嗜碱性粒细胞。在体外，这些 IgG 抗体可以通过阻止 IgE 被激活来防止过敏原效应细胞的激活。通过过敏原交联并与抑制性受体结合。我们之前的工作重点是 Ara h 2，它是最具免疫优势和临床相关的花生过敏原。在那项研究中，Ara h 2 的抑制刺激了嗜碱性粒细胞是耐受性的生物标志物，而 Ara h 2 特异性 IgG 的浓度则不是。因此，我们假设 OIT 后的耐受性是由于诱导了独特的保护性 IgG 克隆而不是过敏原特异性 IgG 普遍增加。这些保护性抗体可有效防止 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应性与 Ara h 2 的关键表位结合，并且该表位- 特异性保护性抗体可以功能性抑制不同患者的过敏原特异性 IgE。我们的该方法涉及使用从单个抗原特异性 B 细胞中克隆的重组抗体，该 B 细胞分离自 OIT 后有或没有耐受性的个体。我们具有独特的优势来开展这项研究，因为我们有抗原特异性 B 细胞亲和选择、重组抗体克隆和抗体方面的专业知识来自独特患者队列的特征。我们将在以下具体目标中解决我们的假设：（1）定义耐受性中保护性过敏原特异性 IgG 抗体的 Ara h 2 结合特征；和（2）识别耐受性中的功能性抑制性过敏原特异性 IgG 抗体。我们预计拟议的研究将阐明长期临床治疗之间的联系 OIT 在具有保护性抗体的克隆水平上的功效，强调了特定克隆在赋予食物过敏的长期耐受性。这项工作将带来食品处理的新策略过敏。