MECHANISMS OF AUTOANTIBODY PRODUCTION IN SLE

SLE 自身抗体产生机制

• 批准号: 2837537
• 负责人: WESTLEY H REEVES
• 金额: $ 21.57万
• 依托单位: UNIV OF NORTH CAROLINA CHAPEL HILL
• 依托单位国家: 美国
• 财政年份: 1991
• 资助国家: 美国
• 起止时间: 1991-08-01 至 1999-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2837537
• 关键词: Baculoviridae; T lymphocyte; antibody formation; antigen antibody reaction; antigen presentation; autoantibody; autoantigens; epitope mapping; human subject; laboratory mouse; molecular cloning; monoclonal antibody; systemic lupus erythematosus; systemic scleroderma; tissue /cell culture; vaccinia virus

Antinuclear antibodies are a central feature of SLE and related rheumatic diseases, and are thought to be directly involved in the pathogenesis of these disorders. The antigens recognized by these autoantibodies are generally components of large DNA-protein or RNA-protein particles. It has been shown that Th clones inducing the production of pathogenic anti-DNA antibodies are responsive to DNA-histone complexes, but not to either DNA or histones alone. We have found that autoantibody production and the activation of autoreactive T cells specific for a chromatin protein can be triggered by alterations in its quaternary structure induced by the binding of a viral protein. Thus, the quaternary structure of an autoantigen may be critical for the presentation of epitopes recognized by autoreactive T cells. In view of the importance of quaternary structure in generating autoreactive T cells, it seems worthwhile to characterize the interactions of autoantigenic chromatin proteins with other self and nonself antigens. This competitive renewal application will extend our previous work on the Ku (p70/p80) heterodimer, a nonhistone chromatin antigen recognized by autoantibodies found in the sera of certain patients with systemic lupus erythematosus (SLE), systemic sclerosis (SSc), and overlap syndromes. The basis for autoimmunity to this autoantigen in human disease will also be examined. We hypothesize that the binding of either foreign antigens or autoantibodies to certain functional domains of Ku or other antigens may trigger autoimmunity by enhancing the presentation of cryptic T cell epitopes of self to which tolerance is incomplete. In Specific Aim 1, the domains of Ku mediating p70-p80 dimerization and binding to a 350 kDa protein (p350) with DNA-dependent protein kinase activity will be determined using prokaryotic and eukaryotic expression systems and specific monoclonal antibodies generated previously in our laboratory. Parallel studies will address the question of whether the same domains are involved in interactions with foreign (viral) antigens that might potentially trigger autoimmunity. In Specific Aim 2, the importance of these functional domains as targets of autoantibodies in SLE, SSc and overlap syndrome will be determined. The HLA associations of autoantibodies to individual epitopes of Ku will be determined, and the basis for the association of anti-Ku, anti-Su, and anti-RNA polymerase II autoantibodies in many sera will be explored. Finally, the possibility that autoantibodies of particular specificities can spread autoimmunity from one antigen to another by altering antigen processing will be investigated. Although the latter studies are exploratory in nature, they may provide direct evidence that the binding of certain autoantibodies, like some foreign proteins, can trigger autoimmunity by altering the quaternary structure of an autoantigen.

抗核抗体是 SLE 和相关风湿病的核心特征 疾病，并被认为直接参与疾病的发病机制 这些疾病。这些自身抗体识别的抗原是 通常是大DNA-蛋白质或RNA-蛋白质颗粒的成分。它有 研究表明，Th 克隆可诱导产生致病性抗 DNA 抗体对 DNA-组蛋白复合物有反应，但对任何一种 DNA 都没有反应 或单独的组蛋白。我们发现自身抗体的产生和 特定于染色质蛋白的自身反应性 T 细胞的激活可以 由其四级结构的变化引发 病毒蛋白的结合。因此，四级结构 自身抗原可能对于表位的呈现至关重要 自身反应性T细胞。鉴于四级结构在 产生自身反应性 T 细胞，似乎值得表征 自身抗原染色质蛋白与其他自身和其他蛋白的相互作用 非自身抗原。这项具有竞争力的续订申请将延长我们的 之前关于 Ku (p70/p80) 异二聚体（一种非组蛋白染色质）的工作 某些患者血清中发现的自身抗体识别的抗原 患有系统性红斑狼疮 (SLE)、系统性硬化症 (SSc) 和 重叠综合症。人类对该自身抗原产生自身免疫的基础 疾病也会受到检查。我们假设两者的结合 针对 Ku 或某些功能域的外来抗原或自身抗体 其他抗原可能通过增强抗原的呈递来触发自身免疫 自身的隐性 T 细胞表位，其耐受性不完全。在 具体目标 1，Ku 介导 p70-p80 二聚化的结构域和 通过 DNA 依赖性蛋白激酶与 350 kDa 蛋白 (p350) 结合 将使用原核和真核表达来确定活性 系统和之前在我们的系统中生成的特异性单克隆抗体 实验室。平行研究将解决是否相同的问题 结构域涉及与外来（病毒）抗原的相互作用 可能会引发自身免疫。在具体目标 2 中，重要性 这些功能域作为 SLE、SSc 和 SSc 中自身抗体的靶标 将确定重叠综合症。 HLA 协会 将确定针对 Ku 的各个表位的自身抗体，并且 抗 Ku、抗 Su 和抗 RNA 聚合酶 II 关联的基础 将探索许多血清中的自身抗体。最后，可能性 特定特异性的自身抗体可以传播自身免疫 通过改变抗原加工从一种抗原到另一种抗原将是 调查了。尽管后者的研究本质上是探索性的，但 可以提供直接证据证明某些自身抗体的结合， 像一些外来蛋白质一样，可以通过改变 自身抗原的四级结构。