Proximal Determinants of Nephritogenic Autoimmunity

描述（由申请人提供）：自身免疫是大多数肾小球肾炎的前兆，肾小球肾炎是世界范围内终末期肾脏疾病的最常见原因。然而，对病因的初步了解迫使我们依赖非特异性毒性免疫抑制疗法。我们开发了Ig转基因（Tg）小鼠，这些小鼠携带与肾源性抗原（Ag）反应的B细胞，作为解剖破坏肾脏的体液自身免疫控制机制的工具。我们认为：a)与肾损伤相关的具有不同结构的自身抗原反应的B细胞受到多种机制的调控；b)自身免疫与非自身免疫个体以及携带不同易感基因星座的个体之间，维持b细胞对肾源性Ag耐受性的分子途径存在差异；c)在全身性和器官限制性疾病中，促进肾炎的B细胞调节存在根本差异。这预示着不同的自身免疫性肾肽会破坏不同的调节机制。我们将使用Ig Tg模型来追求以下具体目标：1)确定缺失和能量在调节B细胞与基底膜反应中的作用，这是人类自身免疫性肾炎中唯一确认的靶点。在抗层粘连蛋白LamH/LamL和双特异性LamH/VSR“单克隆”H+L Ig Tg小鼠中，灭活的Rag或内源性Ig基因将把细胞命运与Ag特异性联系起来，从而消除了附带的调节影响。2)剖析B细胞耐受性基因改造的分子基础。微阵列将用于监测和分析来自自身免疫MRL和非易感B6小鼠的受体刺激耐受性Tg细胞的转录谱，以揭示中枢调控途径。具有明确耐受性表型的LamH Tg也将在肾炎易感性（NZBxNZW）F1和BXSB菌株上建立，以确定单一ag受体相互作用是否在遗传上不同的疾病易感宿主中具有差异耐受性。3)分别测定和比较与肾炎相关的肾反应性238H Ig和抗α 3(IV) NC1胶原Tg B细胞在全身性和肾限制性自身免疫中的命运。这将评估核酸交叉反应性和银固存的贡献，已知影响免疫沉积的因素，对肾源性B细胞的调节。总的来说，这些研究将确定调节途径，以针对量身定制的药物干预免疫肾脏疾病。

DESCRIPTION (provided by applicant): Autoimmunity is the antecedent to most glomerulonephritis, the most common cause of end stage renal disease worldwide. Yet rudimentary understanding of etiology compels reliance on non-specific toxic immunosuppressive therapy. We developed Ig transgenic (Tg) mice bearing B cells reactive with nephritogenic antigens (Ag) as tools to dissect mechanisms controlling humoral autoimmunity that destroys kidney. We postulate that: a) B cells reactive with structurally diverse self-Ag relevant to renal injury are regulated by diverse mechanisms; b) There are differences in molecular pathways maintaining B cell tolerance to nephritogenic Ag in autoimmune vs nonautoimmune individuals, and between individuals bearing different constellations of susceptibility genes; and, c) There are fundamental differences in regulation of B cells that promote nephritis in systemic versus organ-restricted disease. This predicts that different regulatory mechanisms are breached in different autoimmune nephritides. We will use Ig Tg models to pursue the following Specific Aims: 1) Determine the role of deletion and anergy in regulating B cells reactive with basement membrane, the only confirmed target in human autoimmune nephritis. Inactivated Rag or endogenous Ig genes will link cell fate to Ag specificity using anti-laminin LamH/LamL and duat specific LamH/VSR "monoclonal" H+L Ig Tg mice in which collateral regulatory influences are eliminated. 2) Dissect the molecular basis of genetic modification of B cell tolerance. Microarray will be used to monitor and analyze transcriptional profiles in receptor-stimulated tolerant Tg cells from autoimmune MRL and nonsusceptible B6 mice to reveal central regulatory pathways. The LamH Tg, with a well defined tolerance phenotype, will also be established on nephritis-prone (NZBxNZW)F1 and BXSB strains to determine if a single Ag-receptor interaction is differentially tolerogenic in genetically disparate disease-susceptible hosts. 3) Determine and compare the fate of kidney-reactive 238H Ig and anti-alpha3(IV) NC1 collagen Tg B cells associated with nephritis in systemic versus renal-limited autoimmunity, respectively. This will assess contributions of nucleic acid crossreactivity and Ag sequestration, factors known to impact immune deposition, to regulation of nephritogenic B cells. Collectively these studies will identify regulatory pathways to be targeted for tailored pharmacologic intervention in immunologic renal disease.