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: 8020905
• 负责人: Lawrence J Wysocki
• 金额: $ 7.72万
• 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 2013-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8020905
• 关键词: Adjuvant; Affinity; Antibodies; Antigens; Arginine; 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 淋巴细胞在自我耐受中受到许多检查点的影响，这些检查点由至少三种机制强制执行，包括无反应性、受体编辑和克隆删除。然而，在某些自身免疫性疾病中，例如系统性红斑狼疮 (SLE)，它们以某种方式设法逃避所有这些检查点，通过克隆扩增进行繁殖，并产生高亲和力自身抗体，这些抗体是 T 细胞依赖性免疫的产物。该实验室最近的实验提供了有关这一悖论的重要见解。我们的数据首次最终表明，在自发性 SLE 小鼠模型中，狼疮抗核 B 细胞经常是通过体细胞超突变 (SHM) 过程从正常非自身反应性前体细胞中重新产生的。因此，它们能够以耐受方式穿越所有早期免疫前检查点，因为它们不会发生自身反应，直到它们在外周获得体细胞突变，大概是在生发中心（GC）反应期间。这一发现强调了体液免疫反应过程中 B 细胞分化后期发生的自我耐受检查点的重要性。因此，为了了解突变型自身免疫 B 细胞在生理情况下如何正常调节，以及它们在疾病情况下如何逃避自我耐受，我们建议生成一种新的 Ig 基因靶向模型，该模型将使我们能够分析运作的自我耐受机制免疫期间。这是一项重要的努力，因为目前所有的 Ig 转基因或抗核 B 细胞的基因靶向模型都使用从骨髓中淋巴细胞生成过程中出现的那一刻起就表达自身反应性受体的细胞。因此，B 细胞在遇到抗原之前具有不同程度的耐受性。我们提出的模型将利用 CRE 重组酶介导的缺失将非自身反应性 B 细胞转化为自身反应性 B 细胞，因为它参与免疫反应，从而模拟通过 SHM 自然发生的事件。由此产生的自身反应性 B 细胞将被 GFP 标记。此外，它们还表达一种受体，该受体最初源自患有 SLE 的小鼠体内自发产生的实际自身免疫 B 细胞。该模型提供的 B 细胞特异性控制将使我们能够以前所未有的分辨率水平定义生理条件下 GC 和 GC 后发育阶段的自我耐受检查点，以及相反的自身免疫中的逃逸机制。如果我们要了解自身反应性 B 细胞如何逃避自我耐受的最终检查点，以便最终设计出合理的疗法来在身体或功能上使它们沉默，那么这个模型至关重要。 公共健康相关性：产生针对自身组织的抗体的 B 淋巴细胞是系统性自身免疫性疾病（例如系统性红斑狼疮 (SLE)）的主要参与者。该项目旨在开发一种独特的最先进模型，以了解这些潜在危险细胞在生理情况下通常如何被遏制或消除，以及它们有时如何逃避控制机制来参与自身免疫性疾病。从该模型获得的信息将为合理设计治疗方法提供基础，以控制或预防 B 细胞在其中发挥重要作用的自身免疫性疾病。