ARTHRITOGENIC IGS--WHAT ARE THEY? WHY ARE THEY MADE?

关节炎性 IGS——它们是什么？

• 批准号: 6512159
• 负责人: DIANE J MATHIS
• 金额: $ 39.75万
• 依托单位: JOSLIN DIABETES CENTER
• 依托单位国家: 美国
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-03-01 至 2005-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6512159
• 关键词: B lymphocyte; T lymphocyte; antibody formation; autoantigens; disease /disorder model; gene targeting; genetic library; genetically modified animals; immune tolerance /unresponsiveness; laboratory mouse; leukocyte activation /transformation; monoclonal antibody; pathologic process; protein purification; rheumatoid arthritis; rheumatoid factor

Rheumatoid arthritis is a common and debilitating autoimmune disease whose etiology and pathogenesis remain unknown. Small animal models of RA provide a means to dissect disease mechanisms. A mouse model that spontaneously develops a joint disorder with most of the characteristics of RA in humans was recently described. Disease in K/BxN mice is joint-specific, but is provoked by systemic T lymphocyte self-reactivity, resulting in pervasive T cell stimulation and broad B cell activation; both T and B cells are required. The critical role of B cells is to produce arthritogenic immunoglobulins: small amounts of serum from K/BxN mice can precipitate arthritis within days in healthy recipients, even those lacking lymphocytes; the serum activity resides in the IgG fraction and is neither rheumatoid factor nor anti-collagen antibodies. The two major goals of the experiments proposed here are to define the target(s) of the arthritogenic Igs generated in KBxN mice, and to determine what factors are responsible for their selective production, amongst the multitude of potentially autoreactive Igs. More specifically, we propose to: (i) Identify the self-antigen(s) recognized by the arthritogenic Igs following three strategies - based on production of arthritis-promoting monoclonal antibodies, biochemical purification of tissue proteins, or screening of prokaryotic cDNA expression libraries. (ii) Elucidate the factors dictating selective secretion of the arthritogenic Igs, focussing on how the overwhelming T cell stimulation characteristic of this model, with its potential for universal non-cognate "help" for B cells, influences the fate and activity of B cells with various Ag specificities. Comparisons will be made between B cells that recognize self versus non-self Ags, and that see their Ags at different sites, in different forms or at different concentrations by crossing the KBxN strain with various already existing Ig or Ig/Ag transgenic or knock-in lines. (iii) Determinate how tolerance of B cells expressing an arthritogenic specificity is maintained and broken by engineering the appropriate Ig gene knock-ins, and monitoring the behavior of their B cells in the normal context and in KBxN mice. We anticipate that these studies will provide important clues to the pathogenesis of arthritis in the K/BxN model and, hopefully, by extrapolation, in human patients.

类风湿性关节炎是一种常见的自身免疫性疾病，其病因和发病机制尚不清楚。 RA的小动物模型提供了一种剖析疾病机制的方法。 最近描述了一种自发发展具有人类RA大部分特征的关节疾病的小鼠模型。 K/BxN小鼠的疾病是关节特异性的，但由全身性T淋巴细胞自身反应性引起，导致广泛的T细胞刺激和广泛的B细胞活化; T和B细胞都是必需的。 B细胞的关键作用是产生致关节炎的免疫球蛋白：来自K/BxN小鼠的少量血清可以在健康受者中在几天内诱发关节炎，即使是那些缺乏淋巴细胞的受者;血清活性存在于IgG组分中，并且既不是类风湿因子也不是抗胶原抗体。本文提出的实验的两个主要目标是定义KBxN小鼠中产生的致关节炎Ig的靶标，并确定在众多潜在自身反应性Ig中，哪些因子负责其选择性产生。 更具体地说，我们提出：（i）根据三种策略-基于关节炎促进单克隆抗体的产生、组织蛋白的生化纯化或原核cDNA表达文库的筛选，鉴定由致关节炎Ig识别的自身抗原。(ii)阐明决定致关节炎性Ig选择性分泌的因素，重点关注该模型的压倒性T细胞刺激特征及其对B细胞的普遍非同源“帮助”的潜力如何影响具有各种Ag特异性的B细胞的命运和活性。 通过将KBxN菌株与各种已经存在的IG或IG/Ag转基因或敲入系杂交，将在识别自身与非自身Ag的B细胞之间进行比较，并在不同位点、不同形式或不同浓度下观察到它们的Ag。(iii)确定表达致关节炎特异性的B细胞的耐受性是如何通过工程化适当的IG基因敲入来维持和破坏的，并监测它们的B细胞在正常情况下和KBxN小鼠中的行为。我们预计，这些研究将提供重要的线索，关节炎的发病机制在K/BxN模型，并希望通过外推，在人类患者。