A Reporter for Mutant Autoreactive B Cells

突变自身反应性 B 细胞的报告基因

• 批准号: 7871979
• 负责人: Lawrence J Wysocki
• 金额: $ 7.8万
• 依托单位: NATIONAL JEWISH HEALTH
• 依托单位国家: 美国
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-02-15 至 2012-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7871979
• 关键词: Adjuvant; Affinity; Antibodies; Antigens; Arginine; Arts; Autoantibodies; Autoimmune Diseases; Autoimmune Process; Autoimmunity; B cell differentiation; B-Lymphocytes; Bone Marrow; Cells; Characteristics; Chromatin; Clonal Deletion; Clonal Expansion; Codon Nucleotides; Color; Cyan Fluorescent Protein; Data; Detection; Development; Disease; Enterobacteria phage P1 Cre recombinase; Environment; Event; Flow Cytometry; Gene Targeting; Generations; Genes; Genetic Recombination; Goat; Immune response; Immunity; Immunoglobulin Genes; Immunoglobulin Somatic Hypermutation; Internal Ribosome Entry Site; Label; Laboratories; Lupus; Lymphopoiesis; Mediating; Modeling; Mus; Mutate; Nuclear; Participant; Pathway interactions; Phenotype; Physiological; Play; Positioning Attribute; Process; Proteins; Reaction; Reagent; Recruitment Activity; Reporter; Resolution; Role; Self Tolerance; Signal Transduction; Simulate; Site; Somatic Mutation; Specificity; Staging; Structure of germinal center of lymph node; System; Systemic Lupus Erythematosus; T-Lymphocyte; Testing; Time; Tissues; Transgenes; anergy; autoreactive B cell; base; design; in vivo; insight; mouse model; mutant; novel; prevent; public health relevance; receptor; recombinase; research study; response; systemic autoimmune disease; therapy design

DESCRIPTION (provided by applicant): B lymphocytes are subject to many checkpoints in self-tolerance enforced by at least three mechanisms that include anergy, receptor editing and clonal deletion. Nevertheless, in certain autoimmune diseases such as systemic lupus erythematosus (SLE), they somehow manage to evade all of these checkpoints, multiply by clonal expansion and produce high-affinity autoantibodies that are products of T cell-dependent immunity. Recent experiments from this laboratory provide important insight regarding this paradox. Our data conclusively show for the first time, in a spontaneous mouse model of SLE, that lupus anti-nuclear B cells are frequently created de novo from normal nonautoreactive precursors via the process of somatic hypermutation (SHM). As such, they are able to traverse all of the early preimmune checkpoints in tolerance because they are not autoreactive until they acquire somatic mutations in the periphery, presumably during germinal center (GC) reactions. This finding underscores the importance of self-tolerance checkpoints that occur at late stages of B cell differentiation during humoral immune responses. Therefore, to understand how mutant autoimmune B cells are normally regulated under physiological circumstances, and how they escape self-tolerance under disease circumstances, we propose to generate a novel Ig gene-targeted model that will allow us to analyze self-tolerance mechanisms that operate during immunity. This is an important endeavor because all current Ig transgene or gene-targeted models of anti-nuclear B cells employ cells that express autoreactive receptors from the moment they arise during lymphopoiesis in the bone marrow. As such, the B cells are tolerant to varying degrees prior to antigen encounter. The model we propose will make use of CRE recombinase-mediated deletion to convert a nonautoreactive B cell into an autoreactive B cell as it participates in an immune response, thus simulating an event that occurs naturally via SHM. The autoreactive B cells thus generated will become labeled with GFP. In addition, they will express a receptor originally derived from an actual autoimmune B cell that arose spontaneously in a mouse with SLE. The control of B cell specificity afforded by this model will enable us to define self-tolerance checkpoints at the GC and post-GC stages of development under physiological conditions, and conversely mechanisms of escape in autoimmunity, at an unprecedented level of resolution. This model is essential if we are to understand how autoreactive B cells evade the final checkpoints in self-tolerance so that rational therapies can ultimately be designed to silence them physically or functionally. PUBLIC HEALTH RELEVANCE: B lymphocytes that produce antibodies directed against self-tissues are major participants in systemic autoimmune diseases such as systemic lupus erythematosus (SLE). This project aims to develop a unique state-of-the-art-model to understand how these potentially dangerous cells are normally contained or eliminated under physiological circumstances and conversely how they sometimes evade control mechanisms to participate in autoimmune disease. The information obtained from this model will provide a basis for the rational design of therapies to control or prevent autoimmune diseases in which B cells play a significant role.

描述（由申请人提供）：B淋巴细胞在至少三种机制中执行的自耐受的许多检查点，包括厌食，受体编辑和克隆删除。然而，在某些自身免疫性疾病中，例如全身性红斑狼疮（SLE），它们以某种方式设法逃避了所有这些检查点，乘克隆扩张并产生高亲和力自身抗体，这些自身抗体是T细胞依赖性免疫的产物。该实验室的最新实验提供了有关此悖论的重要见解。我们的数据首次在SLE的自发小鼠模型中首次表明，狼疮抗核B细胞经常是通过体细胞超突变（SHM）的过程从正常非运动反应性前体开始创建的。因此，他们能够以耐受性遍历所有早期免疫前检查点，因为它们直到获得周围的体细胞突变（大概是在生发中心（GC）反应中）才具有自动反应性。这一发现强调了在体液免疫反应过程中B细胞分化后期发生的自耐耐受检查点的重要性。因此，为了了解通常在生理环境下通常调节突变体自身免疫性B细胞，以及它们如何在疾病情况下逃脱自我耐受性，我们建议产生一种新型的IG基因基因靶向模型，以使我们能够分析免疫期间运作的自我耐受机制。这是一项重要的努力，因为抗核B细胞的所有当前Ig转基因或基因靶向基因靶向模型都采用细胞来表达自动反应性受体，从骨髓中的淋巴细胞中产生的那一刻起就产生。因此，B细胞在抗原相遇之前耐受程度的不同程度。我们提出的模型将利用CRE重组酶介导的缺失将非运动反应性B细胞转换为自动反应性B细胞，因为它参与了免疫反应，从而模拟了通过SHM自然发生的事件。因此，因此产生的自动反应性B细胞将用GFP标记。此外，它们将表达最初来自实际自身免疫性B细胞的受体，该受体在带有SLE的小鼠中自发产生。该模型提供的B细胞特异性的控制将使我们能够在生理条件下的GC和GC后发育后的自我耐受检查点，并以前所未有的分辨率水平的自身免疫性逃生机制。如果我们要了解自动反应性B细胞如何自我耐受地逃避最终检查点，以便最终可以设计理性疗法以在物理或功能上沉默它们，则该模型至关重要。 公共卫生相关性：产生针对自我组织的抗体的B淋巴细胞是系统性自身免疫性疾病（例如全身性狼疮红斑（SLE））的主要参与者。该项目旨在开发一种独特的最先进的模型，以了解这些潜在危险的细胞通常在生理环境中如何包含或消除，相反，它们有时如何逃避控制机制以参与自身免疫性疾病。从该模型获得的信息将为控制或预防B细胞发挥重要作用的自身免疫性疾病的理性设计提供基础。