Interferon regulation of gamma delta intraepithelial lymphocyte activation

项目总结。 粘膜屏障的免疫监视对于提供对入侵的即时防御至关重要。 然而，微生物也必须受到严格的监管，从而限制自身免疫的可能性。上皮内淋巴细胞 表达γδT细胞受体(γδIEL)是连接先天免疫和获得性免疫的桥梁，并作为第一条线发挥作用。 通过促进粘膜屏障的完整性来防御。最近的报道表明，γδ的基本IEL功能是 受外来微生物信号的影响。虽然共融合诱导的强直性I型干扰素(干扰素)信号 已被证明启动粘膜先天免疫和宿主对病原体的反应性，参与 I型干扰素在γδ中的激活和上皮性监测仍不清楚。我们的初步数据显示 结构性低水平I型干扰素信号调节V-γTCR的适当数量和比例 上皮室中的亚群并保持这些细胞处于活跃的巡逻状态，但在免疫上 静止状态。我们现在证明，干扰素α/β受体(IFNAR)的激活受损会导致一种失调的 γδ为IEL表型，以高增殖、高动力和IL-4表达增强为特征。此外，我们 发现病原体相关水平的I型干扰素可放大γδIEL效应器功能，包括上皮细胞 监视系统。因此，我们建议询问强直的I型干扰素信号维持的机制。 γδIEL动态平衡，而I型干扰素对病原体的放大增强了γδIEL效应 功能。在第一个目标中，我们将利用允许可诱导的γδT细胞特异性的遗传模型 删除iFNAR以研究紧张性iFNAR/STAT信号在维持γδ内分泌平衡中的作用 通过适当调节不同的V-γ亚群。我们还将调查通过哪些机制 IFNAR信号调节不同γδIEL子集之间的串扰以及这如何影响增殖， 这些细胞的运动和效应器功能。接下来，我们将确定γδIEL的功能结果 稳态条件下上皮屏障完整性的失调。在第二个目标中，我们将检查 I型干扰素在病毒感染后增强γδIEL效应功能的机制。用小说 我们首创的活体显微技术以及我们在体外和体内流畅移动的能力 模型，我们将研究病原体相关水平的I型干扰素诱导的分子信号 加强γδ上皮细胞的监测和激活。最后，基于γδIEL在 ，我们将研究I型干扰素诱导的γδIEL激活在以下背景下的作用 急性肠道病毒感染。通过结合时间和细胞特异性的基因打靶，尖端的实时成像 技术和新的模型来分析γδIEL的体外功能，我们期望定义分子 I型干扰素在体内平衡条件下和感染期间调节γδIEL的机制。这个 拟议的研究将为调节γδIEL激活和 γδ效应器功能增强在多大程度上影响上皮完整性和宿主防御。

PROJECT SUMMARY. Immune surveillance at mucosal barriers is essential to provide an immediate defense against invasive microbes, yet must also be tightly regulated limit the potential for autoimmunity. Intraepithelial lymphocytes expressing the γδ T cell receptor (γδ IEL) bridge innate and adaptive immunity, and function as a first line of defense by promoting mucosal barrier integrity. Recent reports demonstrate that basal γδ IEL function is influenced by extrinsic microbial signals. Although commensal-induced tonic type I interferon (IFN) signaling has been shown to prime mucosal innate immunity and host responsiveness to pathogen, the involvement of type I IFN in γδ IEL activation and epithelial surveillance remains unknown. Our preliminary data demonstrate that constitutive low level type I IFN signaling regulates the appropriate number and proportion of Vγ TCR subsets in the epithelial compartment and maintain these cells in an actively patrolling, yet immunologically quiescent state. We now show that impaired interferon α/β receptor (IFNAR) activation induces a dysregulated γδ IEL phenotype, characterized by hyperproliferation, hypermotility and enhanced IL-4 expression. Further, we find that pathogen-associated levels of type I IFN amplify γδ IEL effector functions, including epithelial surveillance. Therefore, we propose to interrogate the mechanism by which tonic type I IFN signaling maintains γδ IEL homeostasis, whereas amplification of type I IFN in response to pathogen enhances γδ IEL effector function. In the first aim, we will take advantage of genetic models that permit the inducible γδ T-cell-specific deletion of IFNAR to examine the role of tonic IFNAR/STAT signaling in the maintaining γδ IEL homeostasis through appropriate regulation of different Vγ subsets. We will also investigate the mechanisms by which IFNAR signaling regulates crosstalk between different γδ IEL subsets and how this influences the proliferation, motility and effector function of these cells. Next, we will determine the functional consequence of γδ IEL dysregulation on epithelial barrier integrity under steady-state conditions. In the second aim, we will examine the mechanisms by which type I IFN amplifies γδ IEL effector function following viral infection. Using the novel intravital microscopy techniques that we pioneered and our ability to move fluidly between in vitro and in vivo models, we will investigate the molecular signals induced by pathogen-associated levels of type I IFN to enhance γδ IEL epithelial surveillance and activation. Lastly, based on the protection conferred by γδ IELs in response to enteric pathogens, we will examine the role of type I IFN-induced γδ IEL activation in the context of acute enteric viral infection. By combining, temporal and cell-specific gene targeting, cutting edge live imaging techniques, and novel models to analyze γδ IEL function ex vivo, we expect to define the molecular mechanisms by which type I IFN regulates γδ IELs under homeostatic conditions and during infection. The proposed studies will provide new insight into the molecular mechanisms that regulate γδ IEL activation and the extent to which enhanced γδ IEL effector function affects epithelial integrity and host defense.