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标志是存在抗双链（ds） DNA抗体。我们的目标是了解健康个体如何调节SLE相关自身抗体，并确定其在自身免疫中的表达机制。我们采用的方法是利用仅重链Tg （VH3H9）开发转基因（Tg）模型，该模型可以与内源性轻链配对产生一系列抗dna和非dna抗体（Abs）。该模型的优势在于，抗dsdna B细胞的发育可以在非自身免疫和自身免疫倾向背景下的多种B细胞库中进行跟踪。这项竞争性更新的目的1是比较不同的基因突变对抗dsdna B细胞表型和功能能力的影响，这些基因突变已知会导致sli相关自身抗体的产生。具体来说，lpr/lpr、gld/gld和lyn-/-小鼠将被研究。此外，dsDNA B细胞的调控也将在SLE诱导模型中进行研究。在MRL-lpr/lpr小鼠中使用VH3H9 Tg，我们已经确定了在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。目的二是了解这些现象背后的机制，特别强调识别缺陷Fas （lpr/lpr）在自身抗体表达中的作用。目的III是表征MRL-lpr/lpr小鼠中与抗dsdna B细胞共定位的CD4 T细胞的性质和意义。提出的研究的新颖之处在于，在VH3H9 Tg的背景下，我们可以跟踪抗dsdna B细胞在不同情况下的命运，开始确定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激发SLE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.