A TRANSGENIC MODEL FOR B CELL TOLERANCE AND AUTOIMMUNITY

系统性红斑狼疮(SLE)和狼疮小鼠模型的一个特征是存在抗双链(DS)DNA抗体。我们的目标是了解SLE相关自身抗体在健康个体中是如何调节的，并确定其在自身免疫中表达的潜在机制。我们所采取的方法是利用仅含重链的TG(VH3H9)与内源性轻链配对来建立转基因(TG)模型，以产生一系列抗DNA和非DNA抗体(Abs)。这个模型的优点是可以在非自身免疫和自身免疫倾向背景下的不同B细胞谱系的背景下跟踪抗dsDNA B细胞的发展。这种竞争性更新的目的1是比较已知的导致SLE相关自身抗体产生的不同基因突变对抗dsDNA B细胞的表型和功能能力的影响。具体来说，将研究LPR/LPR、GLD/GLD和LYN-/-小鼠。此外，还将在诱导的SLE模型中研究dsDNA B细胞的调节。在MRL-LPR/LPR小鼠中使用VH3H9 TG，我们已经确定了自身抗体产生之前抗dsDNA B细胞的发育状态和组织定位的变化。目的II是为了了解这些现象背后的机制，特别是识别缺陷Fas(LPR/LPR)在自身抗体表达中所起的作用。目的III研究MRL-lpr/lpr小鼠体内与抗dsDNA B细胞共定位的CD4T细胞的性质和意义。拟议研究的新方面是，在VH3H9TG的背景下，我们可以跟踪抗dsDNA B细胞在不同环境下的命运，开始识别导致自身抗体产生的步骤。了解影响自身抗体产生的参数可能会启发对SLE进行更有针对性的治疗。

A hallmark of systemic lupus erythematosus (SLE), and murine models of lupus, is the presence of anti-double-stranded (ds) DNA Abs. Our goals are to understand how SLE-associated autoantibodies are regulated in healthy individuals and to identify the mechanisms underlying their expression in autoimmunity. The approach we have taken is to develop a transgenic (Tg) model using a heavy chain-only Tg (VH3H9) which can pair with endogenous light chains to generate a spectrum of anti-DNA and non-DNA antibodies (Abs). The advantage of this model is that the development of anti-dsDNA B cells can be tracked in the context of a diverse B cell repertoire in non- autoimmune and autoimmune-prone backgrounds. Aim 1 of this competitive renewal is to compare the effects of distinct genetic mutations that are known to result in the production of SLE-associated autoantibodies on the phenotype and functional capacity of anti-dsDNA B cells. Specifically, lpr/lpr, gld/gld, and lyn-/- mice will be studied. Furthermore, the regulation of dsDNA B cells will also be investigated in induced models of SLE. Using the VH3H9 Tg in MRL-lpr/lpr mice, we have identified changes in the developmental status and tissue localization of anti-dsDNA B cells that precede autoantibody production. Aim II is to understand the mechanisms behind these phenomena, with particular emphasis on identifying the role that defective Fas (lpr/lpr) plays in autoantibody expression. Aim III is to characterize the nature and significance of the CD4 T cells that co-localize with anti-dsDNA B cells in MRL-lpr/lpr mice. The novel aspect of the proposed studies is that, in the context of the VH3H9 Tg, we can follow the fate of anti-dsDNA B cells under diverse circumstances to begin to identify steps that lead to autoantibody production. Knowledge of the parameters that influence the production of autoantibodies may inspire more targeted therapy for SLE.