Implications of B10-like cell expansion in a model of impaired receptor editing

B10 样细胞扩增对受体编辑受损模型的影响

• 批准号: 9244625
• 负责人: Patrick C. Swanson
• 金额: $ 21.83万
• 依托单位: CREIGHTON UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-12-08 至 2018-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9244625
• 关键词: Acetates; Adoptive Transfer; Animals; Antibodies; Antibody Formation; Antibody-Producing Cells; Antigens; Area; Autoantibodies; Autoantigens; Autoimmune Diseases; Autoimmune Process; Autoimmunity; B cell repertoire; B-Cell Development; B-Lymphocyte Subsets; B-Lymphocytes; Binding; Bone Marrow; Cell Communication; Cells; Chronic Lymphocytic Leukemia; Clinical; Competence; Complication; Coupled; Data; Defect; Disease; Etiology; Exhibits; Failure; Feedback; Frequencies; Genes; Humoral Immunities; Immune system; Immunoglobulin M; Immunoglobulins; Immunophenotyping; Immunosuppression; Immunosuppressive Agents; Impairment; In Vitro; Incidence; Inflammatory Response; Interleukin-10; Ionomycin; Lead; Lecithin; Light; Lipopolysaccharides; Lymphocytosis; Mediating; Membrane; Modeling; Mus; Mutation; Outcome; Pathogenicity; Patients; Pattern; Phenotype; Plasma Cells; Play; Population; Production; Property; Receptors, Antigen, B-Cell; Regulatory Pathway; Reporting; Role; Site; Sjogren' s Syndrome; Specificity; Stimulus; T-Lymphocyte; Testing; Transgenes; Transgenic Mice; Work; autoreactive B cell; autoreactive T cell; autoreactivity; base; cytokine; cytopenia; experimental study; insight; interleukin-21; novel; phorbol-12-myristate; prevent; receptor; response

PROJECT SUMMARY/ABSTRACT Although B cells are best known for providing humoral immunity through the production of antigen-specific antibodies, accumulating evidence suggests some B cell subsets can function to negatively regulate inflammatory responses by producing the immunosuppressive cytokine IL10. Perhaps the best characterized of these subsets is the B10 B cell, which is distinctive for its CD5+CD1dhiCD19hi phenotype and ability to secrete IL10 in response to mitogenic stimuli. B10 B cells are thought to promote antigen-specific suppression of autoreactive T cells through an IL10 (B cell) – IL21 (T cell) feedback loop established by cognate B cell-T cell interactions. Interestingly, some CD5+ B cell populations have a propensity to react with membrane- associated self-antigens and may also produce IL10 like B10 B cells. Furthermore, certain diseases associated with expanded CD5+ B cells, such as chronic lymphocytic leukemia and Sjögren’s syndrome, show an increased incidence of autoimmune cytopenias that occur when antibodies attack the host’s own cells. Together, these data raise the possibility that the IL10-dependent feedback mechanism may function in reverse to help constrain B cells reactive to membrane antigens, and that breakdown of this regulatory loop may cause B cell-intrinsic autoimmune manifestations. We previously generated transgenic mice (called dnRAG1 mice) which exhibit a receptor editing defect used to alter B cell receptor specificity away from self- reactivity. These animals show an expanded CD5+ B cell population and impaired antibody production. We have found that dnRAG1 CD5+ B cells share the immunophenotype and IL10-competence of B10 B cells, leading us to hypothesize that a failure to successfully edit B cell receptor specificity against certain self- antigens may cause the B cell to acquire B10-like properties to suppress B cell-intrinsic autoimmunity. Consistent with this hypothesis, we show here that IL10-deficiency in dnRAG1 mice leads to elevated IgM production. This hypothesis will be further tested by analyzing wild-type and dnRAG1 mice on IL10+/+ and IL10-/- backgrounds to compare spontaneous and stimulation-induced antibody levels, autoantigen reactivity profiles, immunoglobulin variable gene usage patterns, and the frequency of IgM antibody-producing cells. We will also determine whether adoptively transferring CD5+ B cells from IL10+/+ dnRAG1 mice into IL10-/- dnRAG1 mice can restore immune suppression in these animals. Furthermore, we will test whether impaired receptor editing in mice expressing a site-directed phosphatidylcholine (PtC)-specific heavy chain transgene enhances CD5+ B cell accumulation and IL10-competence, and suppresses total or PtC-specific IgM production. The results obtained from this study may reveal an important new mechanism for how B cell-intrinsic autoimmunity against certain self-antigens are suppressed, and will identify autoantigens that may be subjected to tolerance induction by receptor editing. This work may also suggest an etiology for certain autoimmune manifestations, like cytopenias, that can arise as a clinical complication in diseases associated with expanded CD5+ B cells.

项目概要/摘要 尽管 B 细胞最出名的是通过产生抗原特异性来提供体液免疫 抗体，越来越多的证据表明一些 B 细胞亚群可以发挥负调节作用 通过产生免疫抑制细胞因子 IL10 来调节炎症反应。也许是最具特色的 这些亚群中的 B10 B 细胞因其 CD5+CD1dhiCD19hi 表型和 分泌IL10以响应有丝分裂刺激。 B10 B 细胞被认为可促进抗原特异性抑制 通过同源 B 细胞-T 建立的 IL10（B 细胞）– IL21（T 细胞）反馈环路来产生自身反应性 T 细胞 细胞相互作用。有趣的是，一些 CD5+ B 细胞群有与膜反应的倾向 相关自身抗原，也可能产生类似 B10 B 细胞的 IL10。此外，某些疾病 与 CD5+ B 细胞扩增相关，例如慢性淋巴细胞白血病和干燥综合征 当抗体攻击宿主自身细胞时，自身免疫性血细胞减少症的发生率会增加。 总之，这些数据提出了 IL10 依赖性反馈机制可能在 逆转以帮助限制 B 细胞对膜抗原的反应，并且破坏该调节环路 可能引起 B 细胞固有的自身免疫表现。我们之前生成了转基因小鼠（称为 dnRAG1 小鼠）表现出受体编辑缺陷，用于改变 B 细胞受体特异性，使其远离自身 反应性。这些动物表现出 CD5+ B 细胞群扩大和抗体产生受损。我们 发现 dnRAG1 CD5+ B 细胞与 B10 B 细胞具有相同的免疫表型和 IL10 能力， 导致我们假设未能成功编辑针对某些自身的 B 细胞受体特异性 抗原可能会导致 B 细胞获得 B10 样特性，从而抑制 B 细胞固有的自身免疫。 与这一假设一致，我们在此表明​​ dnRAG1 小鼠中 IL10 缺乏会导致 IgM 升高 生产。该假设将通过分析野生型和 dnRAG1 小鼠的 IL10+/+ 和 IL10-/- 背景用于比较自发抗体水平和刺激诱导的抗体水平、自身抗原反应性 概况、免疫球蛋白可变基因使用模式以及 IgM 抗体产生细胞的频率。我们 还将确定是否将 CD5+ B 细胞从 IL10+/+ dnRAG1 小鼠过继转移至 IL10-/- dnRAG1 小鼠可以恢复这些动物的免疫抑制。此外，我们将测试受体是否受损 在表达定点磷脂酰胆碱（PtC）特异性重链转基因的小鼠中进行编辑可增强 CD5+ B 细胞积累和 IL10 能力，并抑制总 IgM 或 PtC 特异性 IgM 的产生。这 这项研究获得的结果可能揭示 B 细胞内在自身免疫如何发生的重要新机制 针对某些自身抗原的抗体被抑制，并且会识别可能受到耐受的自身抗原 通过受体编辑诱导。这项工作还可能提出某些自身免疫表现的病因学， 像血细胞减少症一样，它可能是与 CD5+ B 细胞扩增相关的疾病的临床并发症。