MHC association in autoimmune arthritis

包括关节炎在内的许多自身免疫性疾病的易感性和严重程度是 已知与特定的II类MHC等位基因密切相关，但其机制 这些关联仍然未知。我们已经发现， 与II类相关不变链肽（CLIP）的异常低稳定性复合物 不成比例地出现在赋予易感性的等位基因中， 自身免疫我们最近的工作表明，II类/CLIP亲和力的变化影响了细胞的增殖。 模型抗原呈递中II类分子的稳定性、寿命和丰度 细胞（APC），并可以调节抗原呈递。变化的机制 II类/CLIP亲和力可影响自身免疫的易感性，包括 中枢选择事件或外周耐受或激活事件，所有这些都是 由抗原呈递控制。 在这里，我们建议研究不同的II类/CLIP亲和力是否会影响 自身免疫性疾病的发病机制。我们将：1）建立2个短期 小鼠模型，其中CLIP对II类的亲和力已经被调节，使用两种 关节炎倾向的单倍型。这将通过用以下物质重建经辐照的小鼠来实现： 表达具有野生型CLIP的不变链的HSC（对MHC II具有低亲和力）或 突变的CLIP（对MHC II具有高亲和力）; 2）测量II类/CLIP的作用 在来自这些细胞的主要APC类型中，对II类稳定性、寿命和丰度的亲和力 小鼠，包括在炎症刺激的情况下; 3）确定是否调节 BM衍生的APC中II类/CLIP亲和力的增加调节KRN模型中的疾病， 在这个模型中的免疫学特征。这些实验的结果将塑造未来 研究中，我们将把这项工作扩展到第二个关节炎小鼠模型，以及 作为开发一个长期的模型，以研究关节炎的发病机制，使用小鼠， 表达高亲和力的CLIP/Ii。如果在造血细胞中表达高亲和力CLIP， 足够的疾病保护，它可以为个人提供新的治疗选择， 关节炎的风险。尽管多年来人们已经知道某些蛋白质，HLA， 蛋白质，是关节炎和其他衰弱的关键遗传风险因素 自身免疫性疾病，这种遗传联系的解释仍然存在 未知我们将在关节炎小鼠模型中进行实验，以测试 新的假说的机制，这种协会。如果成功，我们 实验将揭示疾病发生的机制， 发病机制，并可能为人们提供新的治疗方法， 关节炎的高危人群

Susceptibility to and severity of many autoimmune diseases, including arthritis, are known to be closely linked with particular class II MHC alleles, but the mechanism of these associations remains unknown. We have found that class II alleles that form unusually low-stability complexes with class II-associated invariant chain peptides (CLIP) are disproportionately represented among alleles that confer susceptibility to autoimmunity. Our recent work indicates that variations in class II/CLIP affinity affect the stability, longevity, and abundance of class II molecules in model antigen presenting cells (APC) and can modulate antigen presentation. Mechanisms by which variations in class II/CLIP affinity could influence susceptibility to autoimmunity include alterations in central selection events or peripheral tolerance or activation events, all of which are controlled by antigen presentation. Here, we propose to study whether varying class II/CLIP affinity can influence autoimmune disease pathogenesis in a whole animal. We will: 1) Establish 2 short-term mouse models in which the affinity of CLIP for class II has been modulated, using two arthritis-prone haplotypes. This will be achieved by re-constituting irradiated mice with HSC expressing invariant chains with wild type CLIP (with low affinity for MHC II) or mutated CLIP (with high affinity for MHC II); 2) Measure the effects of class II/CLIP affinity on class II stability, longevity, and abundance in primary APC types from these mice, including in the context of inflammatory stimuli; 3) Determine whether modulation of class II/CLIP affinity in BM-derived APC modulates disease in the KRN model and key immunologic features in this model. The results of these experiments will shape future studies, in which we will extend this work to the second mouse model of arthritis, as well as develop a long-term model to investigate arthritis pathogenesis using mice that stably express high-affinity CLIP/Ii. If expression of high affinity CLIP in hematopoietic cells is sufficient for disease protection, it may provide new therapeutic options for individuals at risk for arthritis. Although it has been known for a number of years that certain proteins, the HLA proteins, are a critical genetic risk factor for arthritis and other debilitating autoimmune diseases, the explanation for this genetic link has remained unknown. We will perform experiments in a mouse model of arthritis to test a novel hypothesis for the mechanism of this association. If successful, our experiments will shed new light on the mechanism(s) of disease initiation and pathogenesis in arthritis, and may suggest new treatment approaches for people who are at high risk for arthritis.