Regulation of Migration of Autoreactive Germinal Centers and Precursor B Cells

抽象的。这项提议的总体目标是确定IFN？和IL-17在细胞内发挥作用的机制。 协调的方式启动自身抗体（autoAb）形成B细胞在两个人类 和小鼠发展成系统性红斑狼疮（狼疮或SLE）。IL-17 R和IFN R信号传导 与BXD 2小鼠模型中自发生发中心（GC）的形成有关 通过分析IFN受体缺陷型和IL-17受体缺陷型BXD 2小鼠，有大量的 BXD 2小鼠边缘窦中的浆细胞样DC产生局部高水平的IFN？。干扰素 似乎影响GC的形成，促进人口的迁移， CD 21 hi IgMhi CD 23 hi B细胞从边缘区（MZ）到卵泡（FO）。这些B细胞被称为 作为CD 23 hiAPChi B细胞，因为它们具有非常高的抗原（Ag）呈递能力和 诱导比常规FO B细胞强得多的TH-17极化反应。平行分析 表明IL-17通过以下途径促进BXD 2小鼠中GC的形成和稳定 在B细胞中G蛋白信号传导（Rgs）13和Rgs 16的调节物的上调，其然后促进 APChi B细胞在FO区的滞留。我们假设IFNa促进了 然后IL-17将这些细胞定位在FO中，其中CD 4 + T细胞与来自MZ的CD 23 + hiAPChi B细胞结合。 T细胞驻留。由于这些CD 23 hiAPChi B细胞具有增加的APC和共刺激功能， 它们促进TH-17细胞的产生/维持和自发GC的形成。 本文主要探讨三个问题：（1）IFN γ诱导的CD 23 hiAPChi B细胞内流是否 启动BXD 2小鼠中GC的发展？(2)CD 23 hiAPChi B细胞是否对IL-17和IL-18有应答， 促进TH-17细胞的极化，导致BXD 2小鼠中autoAb的产生？（3）可以 IFN α和IL-17调节狼疮患者APChi B细胞的迁移行为我们将分析Ag 共聚焦显微镜观察APChi B细胞对CD 4 T细胞的捕获、转运和呈递 和FACS分析。将在体外测定IL-17和IFNa调节趋化性的能力， 通过使用来自BXD 2-IL-17 r-/-的B细胞分析GFP阳性APChi B细胞的归巢在体内证实， BXD 2-Ifnar-/-、BXD 2-Rgsl 3-/-和BXD 2-Rgsl 6-/-小鼠。该模型的临床相关性 通过分析从外周血中获得的B细胞来评估自身免疫的发展 狼疮患者的血液，用于分析IFN？和IL-17对发育和迁移的影响 APChi B细胞。意义：这些研究应该确定关键的迁移信号和上游 介质，促进自身免疫回路的发展，导致产生高水平的 亲和致病性自身抗体。因此，它们具有鉴定新的候选治疗靶点的潜力 并建议在autoAb介导的自身免疫性疾病中更有效的治疗干预。

Abstract. The overall goal of this proposal is to identify the mechanisms by which IFN¿ and IL-17 act in a coordinated fashion to initiate the development of autoantibody (autoAb)-forming B cells in both human and mouse that develop systemic lupus erythematosus (lupus or SLE). Both IL-17R and IFN¿R signaling have been implicated in the formation of spontaneous germinal centers (GCs) in the BXD2 mouse model of lupus through analysis of IFN¿R-deficient and IL-17R-deficient BXD2 mice. There are high numbers of plasmacytoid DCs in the marginal sinus of the BXD2 mice that produce locally high levels of IFN¿. IFN¿ appears to influence the formation of GCs by promoting the migration of a population of CD21hiIgMhiCD23hi B cells from the marginal zone (MZ) to the follicle (FO). These B cells were referred to as CD23hiAPChi B cells as they have a very high capacity for antigen (Ag) presentation and the ability to induce a much stronger TH-17 polarization response than the conventional FO B cells. Parallel analyses indicate that IL-17 promotes the formation and stabilization of the GCs in the BXD2 mice through upregulation of regulators of G-protein signaling (Rgs)13 and Rgs16 in the B cells, which then promote the retention of APChi B cells in the FO area. We hypothesize that IFNa facilitates the release of the CD23hiAPChi B cells from the MZ and that IL-17 then localizes these cells in the FO where the CD4 T cells reside. As these CD23hiAPChi B cells have increased APC and costimulatory functions, they promote the generation/maintenance of TH-17 cells and the formation of spontaneous GCs. Three major questions will be addressed: (1) Does the IFN¿-induced influx of the CD23hiAPChi B cells initiate the development of GCs in BXD2 mice? (2) Do the CD23hiAPChi B cells respond to IL-17 and promote polarization of TH-17 cells leading to the production of autoAbs in the BXD2 mice? And (3) Can IFNa and IL-17 regulate the migration behavior of APChi B cells in lupus patients? We will analyze Ag capture, transportation and presentation by APChi B cells to CD4 T cells in vivo using confocal microscopy and FACS analysis. The ability of IL-17 and IFNa to regulate chemotaxis will be determined in vitro, and confirmed in vivo by analysis of homing of GFP-positive APChi B cells using B cells from BXD2-Il-17r-/-, BXD2-Ifnar-/-, BXD2-Rgs13-/- and BXD2-Rgs16-/- mice. The clinical relevance of this model of the development of autoimmunity will be assessed by that analysis of B cells obtained from the peripheral blood of lupus patients for the analysis of the effects of IFN¿ and IL-17 on the development and migration of APChi B cells. SIGNIFICANCE: These studies should identify critical migratory signals and upstream mediators that facilitate the development of an autoimmune circuit that leads to the production of high affinity pathogenic autoAbs. Thus, they have the potential to identify novel candidate therapeutic targets and to suggest more effective therapeutic interventions in autoAb-mediated autoimmune diseases.