DC-HIL in Cutaneous Immunity

DC-HIL 在皮肤免疫中的应用

• 批准号: 7035790
• 负责人: Kiyoshi Ariizumi
• 金额: $ 34.28万
• 依托单位: UT SOUTHWESTERN MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-04-01 至 2008-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7035790
• 关键词: Lentivirus; RNase protection assay; T lymphocyte; contact dermatitis; cytokine; dendritic cells; expression cloning; genetic library; genetically modified animals; glycosylation; haptens; laboratory mouse; leukocyte activation /transformation; ligands; lymph nodes; lymphocyte proliferation; membrane proteins; molecular weight; northern blottings; polymerase chain reaction; protein biosynthesis; skin hypersensitivity; transfection /expression vector

Because T cell activation is a highly regulated event with crucial consequences to the host, it is important to understand mechanisms that promote as well as down-regulate it. We discovered DC-HIL, a type I transmembrane protein expressed constitutively at high levels by epidermal Langerhans cells and dendritic cells (DC). Soluble DC-HIL bound to activated (but not naive) T cells, indicating that expression of its T cell ligand (DC-HIL-L) requires activation. In T cell activation assays, immobilized DC-HIL acted as a negative agonist, markedly attenuating T cell proliferation and IL-2 secretion triggered by signaling via the T cell receptor. By contrast, soluble DC-HIL augmented the mixed lymphocyte reaction and exacerbated contact hypersensitivity (CH) when injected intraperitoneally into mice during hapten-challenge (but not during hapten-priming); herein, DC-HIL acted as an antagonist interfering with binding of DC-HIL to DC-HIL-L. We hypothesize that the DC-HIL/DC-HIL-L pathway transmits a potent inhibitory signal to activated T cells and plays an important role in down-regulating effector T cell responses. Our specific aims are to: (1) Determine whether DC-HIL expression on DC modulates antigen presenting cell function in vitro. We will examine the ability of DC engineered genetically to over-express or silence DC-HIL, to activate T cells. (2) Characterize the inhibitory function of DC-HIL/DC-HIL-L pathway in vivo using the CHmodel. We will: identify DC-HIL- or DC-HIL-L-expressing cells in skin and lymph nodes (LN) of hapten-sensitized mice; characterize LN T cells in sensitized mice treated with soluble DC-HIL; compare DC-HIL/DC-HIL-L and PD-1/PD-L pathways for potency, synergy, and kinetics of down-regulated T cell activation; and examine DC-HIL knockout mice for phenotypic and functional changes including CH responses. (3) Identify DC-HIL-L on activated T cells by biochemical methods and an expression cloning strategy. Our results are likely to show great promise for DC-HIL and DC-HIL-L as potential therapeutic targets for immunologic or pharmacologic modulation.

由于T细胞激活是一个高度调节的事件，对宿主产生了至关重要的后果，因此了解促进和下调的机制很重要。我们发现了DC-HIL，这是一种I型跨膜蛋白，由表皮Langerhans细胞和树突状细胞（DC）在高水平上的组成型表达。可溶性DC-HIL与激活（但不是天真的）T细胞结合，表明其T细胞配体（DC-HIL-L）的表达需要激活。在T细胞激活测定中，固定的DC-HIL充当负激动剂，显着衰减T细胞增殖和通过T细胞受体信号触发的IL-2分泌。相比之下，可溶性DC-HIL增强了混合淋巴细胞反应和加剧的接触性超敏反应（CH），当时将腹膜内注射到hapen-challenge期间（但没有在期间） Hapen-Priming）;本文中，DC-HIL充当拮抗剂，干扰了DC-HIL与DC-HIL-L的结合。我们假设DC-HIL/DC-HIL-L途径将有效的抑制信号传递到激活的T细胞中，并在下调效应T细胞反应中起重要作用。我们的具体目的是：（1）确定DC上的DC-HIL表达是否在体外调节抗原呈现细胞功能。我们将检查DC工程在遗传上过表达或沉默DC-HIL激活T细胞的能力。 （2）表征使用Chmodel在体内DC-HIL/DC-HIL-L途径的抑制功能。我们将：鉴定皮肤敏感小鼠的皮肤和淋巴结（LN）中表达DC-HIL或DC-HIL-L-L-L-L-L-L-表达细胞；在用可溶性DC-HIL处理的敏化小鼠中表征Ln T细胞；比较DC-HIL/DC-HIL-L和PD-1/PD-L途径，以进行下调T细胞激活的效力，协同和动力学；并检查DC-HIL基因敲除小鼠是否有表型和功能变化，包括CH反应。 （3）通过生化方法和表达克隆策略鉴定激活的T细胞上的DC-HIL-L。我们的结果可能会显示出DC-HIL和DC-HIL-L作为免疫或药理调节的潜在治疗靶标。