Mast cell regulation of Th2 induction and tolerance breakdown in food allergy

虽然食物过敏已成为一个主要的健康问题，但治疗选择相当有限。有一个 迫切需要确定特定的环境和内源性因素，启动，然后维持过敏 从而可以开发新的基于机制的疗法。我们发现，IgE- 活化的肥大细胞，以引起包括食物过敏反应在内的速发型超敏反应而闻名， 作为食物过敏原传感器和2型免疫反应的佐剂， 食物特异性IgE对肥大细胞的激活作用可以被 相应的特异性。然而，重要的问题仍然没有答案：1）哪些具体方面 IgE激活的肥大细胞可增强2型免疫（Th2、ILC2、IgE + B细胞），2)这些影响 由肥大细胞细胞因子介导？，3)IgG抗体在体内的保护作用，抑制Th2和Th3， 增强Treg应答，由其负信号介导，通过FcgR2b递送，特别是在肥大细胞中 对食物过敏原的反应是否可以通过使用特异性单克隆IgG抗体来激活 抑制途径？本项目将根据以下目标回答这些问题： 目的1：确定IgE激活的肥大细胞如何促进食物过敏： 1.1检测IgE激活的肥大细胞在体内对Th2、Tfh和IgE + B细胞出现的影响， 评估肥大细胞衍生的Th2细胞因子的贡献 1.2检查肥大细胞对新兴效应RORgt + vs.致病性加塔-3+、IRF-4+、IL-4 + Treg的影响 1.3评价Treg对肥大细胞功能的相互TGF β介导的抑制作用 1.4检查IgE激活的肥大细胞对体内ILC2诱导的影响：肥大细胞与肠道的作用 上皮细胞源性细胞因子 目的2：确定IgG：FcgR2b信号如何重置食物过敏中的免疫应答： 2.1评估肥大细胞中IgG抑制信号在抑制2型和恢复中的直接作用 食物过敏中的功能性Treg反应 2.2评价高亲和力人单克隆花生特异性IgG抗体（及其IgG）的作用 从单个B细胞转录组克隆亚类交换变体）对IgE介导的嗜碱性粒细胞活化的影响 2.3使用我们的花生过敏的人源化小鼠模型来测试单克隆花生特异性 IgE对速发型超敏反应（全身性过敏反应）的影响。 2.4测试IgG对人源化小鼠中Th、Tfh和Treg应答的影响

While food allergy has emerged as a major health issue, treatment options are quite limited. There is an urgent need to identify the specific environmental and endogenous factors that prime and then sustain allergic responses to foods so that new mechanism-based therapies can be developed. We have found that, IgE- activated mast cells, best known for causing immediate hypersensitivity reactions including food anaphylaxis, actually play a separate but critical role as food allergen sensors and adjuvants for Type 2 immune responses and that the activating effects of food-specific IgE on mast cells can be countered by IgG antibodies of corresponding specificity. Important questions remain unanswered, however: 1) What specific aspects of Type 2 immunity (Th2, ILC2, IgE+ B cells) are enhanced by IgE-activated mast cells?, 2) Are these effects mediated by mast cell cytokines?, 3) Is the protective effect of IgG antibodies in vivo, suppressing Th2 and enhancing Treg responses, mediated by their negative signals, delivered via FcgR2b, specifically in mast cells and can responses to food allergens be attenuated by using specific monoclonal IgG antibodies to activate this suppressive pathway? These questions will be answered in this project under the following aims: AIM 1: Establish how IgE-activated mast cells promote food allergy: 1.1 Test the impact of IgE-activated mast cells in vivo on emergence of Th2, Tfh and IgE+ B cells and evaluate the contributions of mast cell derived Th2 cytokines 1.2 Examine mast cell effects on emerging effector RORgt+ vs. pathogenic GATA-3+, IRF-4+, IL-4+ Treg 1.3 Evaluate reciprocal TGFb-mediated inhibitory effects of Treg on mast cell functions 1.4 Examine the influence of IgE-activated mast cells on ILC2 induction in vivo: Roles of mast cell- vs. gut epithelial cell-derived cytokines AIM 2: Determine how IgG:FcgR2b signals can reset the immune response in food allergy: 2.1 Evaluate the direct role of IgG inhibitory signals in mast cells in suppression of Type 2 and restoration of functional Treg responses in food allergy 2.2 Evaluate the effects of high-affinity human monoclonal peanut specific IgG antibodies (and their IgG subclass swap variants) cloned from single B cells transcriptomes on IgE-mediated basophil activation 2.3 Use our humanized mouse model of peanut allergy to test the effects of monoclonal peanut-specific IgE on immediate hypersensitivity responses (systemic anaphylaxis). 2.4 Test IgG effects on Th, Tfh and Treg responses in the humanized mice