Role of Memory IgG B Cells in the Development of Tolerance in Food Allergy

只有一部分IgE介导的食物过敏患者在口服后出现临床耐受 免疫疗法(OIT)，已被归因于保护性、功能性抑制的发展 抗体。然而，那些失去耐受性的人通常被认为是早期的过敏原短暂增加- 特异性IgE。此前，我们已经描述了OIT早期过敏原特异性记忆B细胞的诱导，以及 这些特异性的免疫球蛋白B细胞可以通过顺序的类别转换作为免疫球蛋白E记忆的储存库。因此， 特异性Ig G B细胞产生保护性Ig G或Ig A抗体对致病的相对贡献 免疫球蛋白E在OIT免疫耐受的形成中起关键作用。了解该B的贡献 细胞命运的决定可能会导致过敏性疾病的新治疗方式的发展。 在OIT中，我们最近发表了抑制嗜碱性细胞敏感性是耐受性的生物标志物。 嗜碱性粒细胞的功能性抑制而不是大量的过敏原特异性免疫球蛋白与耐受性有关， 提示OIT诱导的抗体谱可能与免疫耐受的形成密切相关。 我们已经开发了一种高度特异的荧光多聚体来鉴定和表征变应原特异性B细胞 以确定这些B细胞的克隆性贡献。使用这些工具，我们建议跟踪 从OIT诱导的记忆免疫球蛋白B细胞向血清后效应抗体的克隆进化解释 特异性免疫球蛋白B细胞的抗体进化如何影响OIT的临床结局。 基于这些发现，我们假设过敏原特异性记忆免疫球蛋白B细胞可以引起 决定卵巢移植后长期耐受性的保护性或致病性抗体。我们的方法 将抗原特异性B细胞的分离用于单细胞BCR测序、BCR谱系分析和 血清蛋白质组学分析花生过敏原Arah2血清抗体的克隆性 当然了。我们有独特的条件来进行这项研究，因为我们有来自 以前的特点是OIT治疗的患者。我们将在以下具体目标中阐述我们的假设：(1) 评价保护性、功能性抑制性变应原特异性免疫球蛋白在持续耐受中的发展 (2)评价顺序转换在OIT后耐受丧失中的作用。 我们预计，拟议的研究将阐明长期临床试验与 OIT在具有保护性和致病抗体的克隆水平上的有效性，突出了OIT的关键作用 记忆过敏原特异性免疫球蛋白B细胞，并导致治疗食物过敏的新策略。这个 利用BCR测序、蛋白质组学和蛋白质组学追踪抗原特异性B细胞命运的技术的发展 重组抗体，将提供一个强大的平台，进一步细化我们对如何体液的理解 免疫力会导致人类的过敏性疾病。

Only a subset of patients with IgE-mediated food allergy develop clinical tolerance after oral immunotherapy (OIT), which has been attributed to the development of protective, functionally suppressive antibodies. However, those who lose tolerance are often seen to have an early transient increase in allergen- specific IgE. Previously, we have described the induction of allergen-specific memory B cells early in OIT, and these specific IgG B cells could serve as a reservoir of IgE memory via sequential class-switching. Therefore, the relative contribution of specific IgG B cells giving rise to protective IgG or IgA antibodies versus pathogenic IgE is critical to the development of immunological tolerance in OIT. Understanding the contributions of that B cell fate decision could lead to the development of new therapeutic modalities for allergic diseases. In OIT, we recently published that suppression of basophil sensitivity is a biomarker of tolerance. Functional suppression of basophils and not bulk levels of allergen-specific IgG is correlated with tolerance, suggesting that the antibody repertoire induced by OIT may be highly relevant to the development of tolerance. We have developed a highly specific fluorescent multimer to identify and characterize allergen-specific B cells in peanut OIT in order to define the clonal contributions of these B cells. Using these tools, we propose to track clonal evolution from the memory IgG B cells induced by OIT to the post-serum effector antibodies to explain how antibody evolution from specific IgG B cells influences clinical outcomes in OIT. Based on these findings, we hypothesize that allergen-specific memory IgG B cells can give rise to either protective or pathogenic antibodies that determine long-lived tolerance after OIT. Our approach combines the isolation of antigen-specific B cells for single-cell BCR sequencing, BCR repertoire analysis, and serum proteomics to dissect the clonality of serum antibodies to the peanut allergen, Ara h 2, over the course of OIT. We are uniquely positioned to conduct this study in that we have both serum and BCR repertoires from previously characterized OIT-treated patients. We will address our hypothesis in the following specific aims: (1) Evaluate the development of protective, functionally suppressive allergen-specific IgG in sustained tolerance after OIT; and (2) Evaluate the role of sequential switching in the loss of tolerance after OIT. We anticipate that the proposed studies will elucidate the connection between long-lasting clinical efficacy of OIT on a clonal level with protective and pathogenic antibodies, highlighting the critical role of memory allergen-specific IgG B cells and leading to new strategies for the treatment of food allergies. The development of techniques to track antigen-specific B cell fate, using BCR sequencing, proteomics and recombinant antibodies, will provide a powerful platform to further refine our understanding of how humoral immunity drives allergic disease in humans.