Gamma Delta T Cells in Lyme Arthritis

描述(申请人提供)：莱姆病是美国最常见的病媒传播疾病，由伯氏疏螺旋体通过肩部硬蜱传播引起。莱姆病的临床表现之一是关节炎，它可以成为慢性疾病，并对抗生素产生抗药性。在莱姆关节炎关节滑液中聚集的淋巴细胞中，有很大一部分是γ/Delta(？)Vd1亚集的T细胞。我们已经确定滑膜V41细胞对伯氏杆菌脂肽(结合Toll样受体2，TLR2)高度反应，表达高水平的Fas配体(FasL)，可能与CD1b反应，并类似于长期激活的T细胞。此外，Vd1细胞通过FasL刺激树突状细胞(DC)的效应功能，树突状细胞通过FasL反馈激活Vd1细胞。树突状细胞对FasL介导的细胞死亡具有抵抗力，这是由于高水平表达Fas死亡受体抑制因子c-FLIP。C-FLIP将信号从caspase级联转移到核因子-βB途径。因此，Fas/FasL可能是？？T细胞和DC的激活。缺乏功能性FasL的小鼠感染伯氏杆菌后，炎症和关节炎明显减轻。因此，该项目研究了莱姆关节炎的三个密切相关的成分：伯氏杆菌、滑膜Vd1 T细胞和树突状细胞(DC)。连接这三个成分的模型是伯氏杆菌将TLR结合在DC上，这是刺激滑膜Vd1细胞的CD1b等分子上调的信号。这也将通过体内感染缺乏TLR、MyD88或CD1d的小鼠来研究。还将进行可溶性Vd1 TCR以鉴定其他Vd1配体(目标1)。滑膜Vd1细胞被CD1b和疏螺旋体脂肽及其TCR/CD3组成的固有特性反复激活，从而导致表面Fas配体(FasL)的高水平表达(Aim 2)。DC也通过FasL从V41细胞接收刺激信号。在DC中存在高水平的Fas抑制因子Flio时，Fas信号通过核因子-βB从死亡途径转移到生长和分化信号，这是通过募集到适配蛋白RIP1和TRAF2的c-Flip而发生的。DC的TLR信号也可能需要caspase-8并通过TRAF6连接。最后，通过过继转移FasL+来研究Fas/FasL在体内的作用。在巨噬细胞和/或DC中选择性地向携带突变FasL或缺乏Fas、caspase-8或c-Flip的小鼠提供T细胞(目标3)。这项工作代表了唯一已知的关于人类的研究？？莱姆关节炎中的T细胞。项目叙事？？T细胞在免疫系统中仍然是一个谜。它们通常定位于上皮屏障，并被认为参与了对各种感染的最初反应。确实起到了保护作用？？在各种感染模型中都观察到了T细胞。?？T细胞也聚集在自身免疫综合征的炎症部位，如类风湿性关节炎的滑膜组织，乳糜泻的肠道，或结节病的肺部。然而，几乎没有什么是关于？？的特殊性的。T细胞。因此，我们正在使用人类和小鼠的莱姆关节炎作为？？感染中的T细胞反应和潜在的自身免疫情况，因为慢性抗生素耐药莱姆关节炎患者在滑膜组织的组成、对免疫抑制剂的反应，甚至是相同的HLA-DR4关联方面与自身免疫性类风湿性关节炎非常相似。该项目将寻求建立滑膜Vd1细胞使用可溶性TCR-Vd1的特异性，以及它们通过高表达Fas配体的效应功能，以及它们通过Fas刺激树突状细胞的能力。了解这些相互作用将提高我们对这些相互作用的理解。在感染和自身免疫条件下，T细胞调节免疫反应。

DESCRIPTION (provided by applicant): Lyme Disease is the most common vector-borne illness in the U.S. and is caused by transmission of the spirochete, Borrelia burgdorferi, via the tick Ixodes scapularis. Among the clinical manifestations of Lyme Disease is arthritis, which can become chronic and resistant to antibiotics. A significant proportion of the lymphocytes that accumulate in Lyme arthritis synovial fluid are gamma/delta (??? T cells of the Vd1 subset. We have determined that the synovial V41 cells are highly responsive to B. burgdorferi lipopeptides (that bind Toll-like Receptor 2, TLR2), express high levels of Fas-Ligand (FasL), may react to CD1b, and resemble chronically activated T cells. Furthermore, the Vd1 cells stimulate effector function of dendritic cells (DC) via FasL, which then feeds back to activate the Vd1 cells. DC are resistant to FasL-mediated cell death due to high level expression of the Fas death receptor inhibitor, c-FLIP. c-FLIP diverts signals from the caspase cascade and toward the NF-?B pathway. Thus, Fas/FasL may be an important link between ?? T cells and activation of DC. Mice lacking functional FasL manifest reduced inflammation and arthritis with B. burgdorferi infection. This project thus examines three closely related components of Lyme arthritis: B. burgdorferi, synovial Vd1 T cells, and dendritic cells (DC). The model connecting these three components is that B. burgdorferi binds TLR on DC, which signal upregulation of molecules such as CD1b that are stimulatory for synovial Vd1 cells. This will be also studied by in vivo infection with B. burgdorferi in mice lacking TLR, MyD88, or CD1d. A soluble Vd1 TCR will also be made to identify other Vd1 ligands (Aim 1). The synovial Vd1 cells become repeatedly activated by CD1b and Borrelia lipopeptides, as well as by properties intrinsic to their TCR/CD3 composition, which results in high level expression of surface Fas-ligand (FasL) (Aim 2). DC in turn receive stimulatory signals also via FasL from V41 cells. In the presence of high levels of the Fas inhibitor FLIP in DC, Fas signals are diverted from death pathways to growth and differentiation signals via NF-?B. This occurs via recruitment to c-FLIP of the adaptor proteins, RIP1 and TRAF2. TLR signaling of DC may also require caspase-8 and connect via TRAF6. Finally, the in vivo role of Fas/FasL will be studied by adoptive transfer of FasL+ ?? T cells to mice bearing mutant FasL or lacking Fas, caspase-8, or c-FLIP selectively in macrophages and/or DC (Aim 3). This work represents the only known research on human ?? T cells in Lyme arthritis. Project Narrative ?? T cells remain an enigma in the immune system. They are often localized at epithelial barriers, and are felt to be involved in the initial response to various infections. Indeed a protective role of ?? T cells has been observed in various infectious models. ?? T cells also accumulate at sites of inflammation in autoimmune syndromes such as in the synovial tissue in rheumatoid arthritis, the bowel in celiac disease, or the lungs in sarcoidosis. However, almost nothing is nothing regarding the specificity of ?? T cells. We are thus using Lyme arthritis in humans and mice as a model of the ?? T cell response in infection and potentially an autoimmune situation, as patients with chronic antibiotic-resistant Lyme arthritis closely resemble autoimmune rheumatoid arthritis in the composition of the synovial tissue, response to immunosuppressive agents, and even the same HLA-DR4 association. This project will seek to establish both the specificity of synovial Vd1 cells using a soluble TCR-Vd1, as well as their effector function through high expression of Fas- ligand and their ability to stimulate dendritic cells by Fas. Understanding these interactions will improve our understanding of how ?? T cell regulate the immune response during infection and autoimmune conditions.