Mechanisms of IgM mediated activation of the complement system

IgM 介导的补体系统激活机制

• 批准号: 10640282
• 负责人: Miklos Guttman
• 金额: $ 48.44万
• 依托单位: UNIVERSITY OF WASHINGTON
• 依托单位国家: 美国
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-06-02 至 2026-05-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10640282
• 关键词: 3-Dimensional; Address; Adopted; Antibodies; Antibody Response; Antibody-mediated protection; Antigen Presentation; Antigens; Architecture; Autoimmune Diseases; Binding; Biological Response Modifier Therapy; Communicable Diseases; Complement; Complement 1q; Complement Activation; Complement component C1; Complement component C1r; Complement component C1s; Complex; Cryoelectron Microscopy; Deuterium; Development; Disease; Electron Microscopy; Foundations; Future; Heterogeneity; Hydrogen; Immobilization; Immune system; Immunity; Immunoglobulin G; Immunoglobulins; Infection; Malignant Neoplasms; Maps; Mass Spectrum Analysis; Mediating; Molecular; Molecular Conformation; Monitor; Outcome; Pharmaceutical Preparations; Phase I Clinical Trials; Polymers; Printing; Process; Recombinants; Refractory; Resolution; Roentgen Rays; Scaffolding Protein; Structure; Surface; Techniques; Testing; Therapeutic; Visualization; antigen binding; arm; biophysical tools; cancer therapy; complement system; density; design; flexibility; foot; glycosylation; immunoglobulin structure; immunoregulation; natural antibodies; pathogen; recruit; response; timeline; tool; transmission process; tumor

SUMMARY Immunglobulin µ (IgM) is an evolutionary old class of antibody that is the first antibody produced in response to an infection. Several IgMs are present as natural antibodies and are vital for immunity during the early stages of development. Unlike any other class of antibody, a single copy is sufficient for activating the classical complement system, and several monoclonal IgMs have shown massive potential for the treatment of cancers. The large size, high degree of glycosylation, and structural heterogeneity of IgM has rendered them refractory to structural studies and to date the molecular mechanisms of how antigen binding activates IgM to initiate the complement cascade remain murky. In contrast, a detailed understanding of the structure and various interactions of immunoglobulin g (IgG) have been fundamental to their advancement as the premier molecular platform for biotherapeutics. Accordingly, a similar level of understanding of IgM will be critical for their development as a new class of biotherapeutics. This proposal aims to apply structural mass spectrometry techniques, electron microscopy with complementary structural approaches, and biophysical tools to study the structural changes within IgM that govern activation of the complement cascade. Various types of IgM-antigen complexes will be prepared and analyzed using hydrogen/deuterium exchange and X-ray foot printing with mass spectrometry to track the local structural changes within IgM upon binding different presentations of antigen (Aim 1). Electron microscopy and small angle X-ray scattering will be used to visualize and track large-scale structural transitions in the antigen-IgM complexes (Aim 2). The full combination of techniques will be used to study how IgM recruits and activates the initial component, C1, of the complement cascade (Aim 3). The molecular mechanisms of how IgM recognizes antigen and recruits complement will provide a foundation for modulating the immune system for a new paradigm in biotherapeutics.

概括 免疫球蛋白 µ (IgM) 是一种进化古老的抗体，是第一种抗体 一些 IgM 作为天然抗体而产生，并且至关重要。 与任何其他类别的抗体不同，单一抗体可在发育的早期阶段提供免疫力。 拷贝足以激活经典补体系统，并且一些单克隆 IgM 尺寸大、程度高的癌症已显示出巨大的治疗潜力。 IgM 的糖基化和结构异质性使它们难以适应结构 研究并确定了抗原结合如何激活 IgM 以启动免疫反应的分子机制 相比之下，级联的结构和详细补充理解仍然模糊。 免疫球蛋白 g (IgG) 的各种相互作用是其进步的基础， 生物治疗的首要分子平台因此具有类似的理解水平。 IgM 的检测对于其作为新型生物治疗药物的开发至关重要。 该提案旨在应用结构质谱技术、电子显微镜 使用互补的结构方法和生物物理工具来研究结构变化 IgM 内控制补体级联激活的各种类型的 IgM 抗原。 将使用氢/氘交换和 X 射线足来制备和分析配合物 质谱打印以跟踪结合后 IgM 内的局部结构变化 抗原的不同表现（目标 1）。 将用于可视化和跟踪抗原-IgM 复合物中的大规模结构转变 （目标 2）。将使用技术的完整组合来研究 IgM 如何招募和激活。 补体级联的初始成分 C1（目标 3）。 IgM 如何识别抗原并招募补体将为调节 免疫系统为生物治疗的新范例。