The Role of IgE in Autoimmune Skin Diseases

IgE 在自身免疫性皮肤病中的作用

• 批准号: 7925120
• 负责人: JANET A FAIRLEY
• 金额: --
• 依托单位: IOWA CITY VA MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-07-01 至 2014-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7925120
• 关键词: Advanced Development; Affinity; Affinity Chromatography; American; Antibodies; Antigens; Area; Autoantibodies; Autoimmune Diseases; Autoimmune Process; Autoimmunity; Basophils; Binding; Binding Sites; Biological Assay; Blood; Bulla; Bullous Pemphigoid; Cell Degranulation; Cell Line; Cell model; Cell surface; Cells; Chemotaxis; Collagen Type XVII; Confocal Microscopy; Cryoultramicrotomy; Cutaneous; Cytokine Signaling; Dendritic Cells; Dermal; Development; Disease; Disease model; Electron Microscopy; Enzyme-Linked Immunosorbent Assay; Epitopes; Event; Funding; Goals; Histamine Release; Human; IgE; IgE Receptors; Immunoblotting; Immunofluorescence Immunologic; Immunoglobulin G; Immunologics; Immunosuppressive Agents; In Vitro; Inflammation Mediators; Inflammatory; Inflammatory Response; Knowledge; Label; Laboratories; Lead; Lesion; Lesion by Stage; Liquid substance; Maps; Measures; Mediating; Microscopy; Modeling; Monitor; Monoclonal Antibodies; Morbidity - disease rate; Morphology; Mus; Pathogenesis; Pathogenicity; Patients; Peptides; Phase; Pilot Projects; Play; Process; Production; Proteins; Reaction; Resolution; Role; Serum; Skin; Source; Steroids; Surface; Testing; Therapeutic Intervention; Time; Tissues; Veterans; Work; Xenograft procedure; anti-IgE; antigen binding; base; conventional therapy; cytokine; disease characteristic; eosinophil; improved; in vitro Model; insight; keratinocyte; light microscopy; mast cell; mortality; mouse model; omalizumab; receptor; receptor expression; skin disorder; synthetic polymer Bioplex

DESCRIPTION (provided by applicant): Bullous pemphigoid (BP) is a blistering disease of the skin characterized by development of autoantibodies directed against BP180, a cell-substrate attachment protein. Antibodies of the IgG class have been the focus of most studies of the pathogenesis of this disorder. However, BP patients have an initial urticarial phase of the disease and 70% of these patients have elevated total IgE levels. IgE antibodies that specifically target BP180 have been identified in 90% of BP patients. These IgE autoantibodies predominantly target the same region of the BP antigen as IgG (NC16A), trigger histamine release from basophils and produce lesions that mimic the early stage of lesion development in BP in a xenograft mouse model. A monoclonal antibody that blocks IgE binding to its receptor led to improvement in a BP patient. HYPOTHESIS: Our central hypothesis is that IgE class autoantibodies against BP180 play a critical role in the pathogenesis of BP. More specifically, we propose that BP IgE manifests its effects via multiple mechanisms that involve binding of the IgE either to BP180 on the surface of epidermal keratinocytes or to its high affinity receptor, Fc5RI, on mast cells and potentially eosinophils. These molecular interactions then trigger a pro-inflammatory response in the keratinocytes, eosinophil chemotaxis and degranulation of mast cells. These events will lead to the development of urticarial plaques and subepidermal bullae characteristic of the disease. Specific objectives of the proposal are: Objective 1. Identify the Fc5RI-mediated effects of BP IgE Objective 2. Determine the Fc5RI-independent effects of BP IgE. Objective 3 . Develop a model of IgE autoimmunity utilizing a murine IgE monoclonal antibody directed against human BP180. This is a laboratory based study that will identify the mechanisms by which human BP IgE class autoantibodies are pathogenic. IgE autoantibodies will be isolated from the sera of BP patients and controls by multi-step affinity chromatography. BP IgE will be tested for its ability to trigger mast cell degranulation in the presence of antigen utilizing an RBL-SX cell model. Expression of Fc5RI on circulating and tissue eosinophils in BP will be determined. The ability of BP IgE to cause degranulation, antigen internalization or cytokine production by eosinophils will be tested. Identification of Fc5RI-independent mechanisms will be identified by treatment of human keratinocytes with BP IgE in vitro. The effects of BP IgE on keratinocyte morphology due to binding of the antibody to its antigenic on the cell surface will be determined by light, confocal and electron microscopy. Production of inflammatory mediators by BP IgE-treated keratinocytes will be identified by human cytokine BioPlex and confirmed by ELISA. An IgE monoclonal antibody against NC16A will be tested for its ability to replicate the findings of patient IgE, in order to develop an in-vitro model of IgE autoimmunity. Understanding the role of IgE autoantibodies in BP will provide insight into the role of IgE in immunologic reactions and lead to new areas for therapeutic intervention. PUBLIC HEALTH RELEVANCE: Autoimmune diseases, once thought to be rare, are now recognized as much more common disorders. In aggregate, the autoimmune disorders are a significant source of morbidity and mortality in millions of veterans and other Americans. Treatment of these patients with long term steroids and immunosuppressive agents is another source of significant morbidity. The goal of this project is to identify the role of IgE autoantibodies in the pathogenesis of autoimmune disorders. The cutaneous autoimmune blistering diseases provide excellent models with which to enhance our knowledge of the pathogenic mechanisms operative in these patients. A better understanding of the importance of each component of the pathogenic process will advance the development of newer, more specific, and safer therapies for these diseases.

描述（由申请人提供）： 大疱性类天疱疮 (BP) 是一种皮肤水疱性疾病，其特征是产生针对 BP180（一种细胞基质附着蛋白）的自身抗体。 IgG 类抗体一直是该疾病发病机制大多数研究的焦点。然而，BP 患者处于疾病的初始荨麻疹期，其中 70% 的患者总 IgE 水平升高。已在 90% 的 BP 患者中发现了特异性靶向 BP180 的 IgE 抗体。这些 IgE 自身抗体主要靶向与 IgG (NC16A) 相同的 BP 抗原区域，触发嗜碱性粒细胞释放组胺，并产生模拟异种移植小鼠模型中 BP 病变发展早期阶段的病变。一种阻断 IgE 与其受体结合的单克隆抗体使 BP 患者的病情得到改善。假设：我们的中心假设是针对 BP180 的 IgE 类自身抗体在 BP 的发病机制中发挥着关键作用。更具体地说，我们认为 BP IgE 通过多种机制发挥其作用，这些机制涉及 IgE 与表皮角质形成细胞表面的 BP180 或其高亲和力受体 Fc5RI 结合，在肥大细胞和潜在的嗜酸性粒细胞上。这些分子相互作用随后引发角质形成细胞中的促炎症反应、嗜酸性粒细胞趋化性和肥大细胞脱颗粒。这些事件将导致荨麻疹斑块和表皮下大疱的发展，这是该疾病的特征。该提案的具体目标是： 目标 1. 确定 BP IgE 的 Fc5RI 介导效应 目标 2. 确定 BP IgE 的 Fc5RI 独立效应。目标3。利用针对人 BP180 的鼠 IgE 单克隆抗体开发 IgE 自身免疫模型。这是一项基于实验室的研究，将确定人类 BP IgE 类自身抗体的致病机制。通过多步亲和层析从 BP 患者和对照的血清中分离 IgE 自身抗体。将使用 RBL-SX 细胞模型测试 BP IgE 在抗原存在下触发肥大细胞脱粒的能力。将测定 BP 中循环和组织嗜酸性粒细胞上 Fc5RI 的表达。将测试 BP IgE 引起嗜酸性粒细胞脱颗粒、抗原内化或细胞因子产生的能力。 Fc5RI 独立机制的鉴定将通过在体外用 BP IgE 处理人角质形成细胞来鉴定。由于抗体与其在细胞表面上的抗原结合而导致 BP IgE 对角质形成细胞形态的影响将通过光学、共聚焦和电子显微镜来确定。 BP IgE 处理的角质形成细胞产生的炎症介质将通过人类细胞因子 BioPlex 进行鉴定，并通过 ELISA 进行确认。将测试针对 NC16A 的 IgE 单克隆抗体复制患者 IgE 结果的能力，以开发 IgE 自身免疫的体外模型。了解 IgE 自身抗体在 BP 中的作用将有助于深入了解 IgE 在免疫反应中的作用，并带来治疗干预的新领域。 公共卫生相关性： 自身免疫性疾病曾经被认为是罕见的，现在被认为是更常见的疾病。总的来说，自身免疫性疾病是数百万退伍军人和其他美国人发病和死亡的重要原因。用长期类固醇和免疫抑制剂治疗这些患者是显着发病的另一个来源。该项目的目标是确定 IgE 自身抗体在自身免疫性疾病发病机制中的作用。皮肤自身免疫性水疱疾病提供了极好的模型，可以增强我们对这些患者致病机制的了解。更好地了解致病过程每个组成部分的重要性将促进针对这些疾病开发更新、更特异和更安全的疗法。