Interferon regulation of gamma delta intraepithelial lymphocyte activation

项目摘要。 粘膜屏障的免疫监视对于提供对侵袭性疾病的直接防御至关重要。 微生物，但也必须严格管制限制自身免疫的潜力。上皮内淋巴细胞 表达γδ T细胞受体（γδ IEL）是连接先天性免疫和适应性免疫的桥梁，并作为第一道免疫屏障发挥作用。 通过促进粘膜屏障完整性来防御。最近的报告表明，基础γδ IEL功能是 受外界微生物信号的影响。虽然干扰素诱导的紧张性I型干扰素（IFN）信号转导 已显示引发粘膜先天免疫和宿主对病原体的反应， I型IFN在γδ IEL激活和上皮监视中的作用尚不清楚。我们的初步数据显示 组成性低水平I型IFN信号调节Vγ TCR的适当数量和比例， 亚群，并维持这些细胞在积极巡逻，但免疫 静止状态我们现在发现，干扰素α/β受体（IFNAR）激活受损可诱导干扰素α/β受体（IFNAR）表达失调。 γδ IEL表型，以过度增殖、过度运动和增强的IL-4表达为特征。我们还 发现病原体相关的I型IFN水平放大γδ IEL效应器功能，包括上皮细胞 监视因此，我们建议询问紧张性I型IFN信号维持的机制， γδ IEL稳态，而响应病原体的I型IFN的扩增增强γδ IEL效应子 功能在第一个目标中，我们将利用遗传模型，该模型允许诱导性γδ T细胞特异性 删除IFNAR，以检查紧张性IFNAR/STAT信号传导在维持γδ IEL稳态中的作用 通过适当调节不同的Vγ亚群。我们还将研究 IFNAR信号转导调节不同γδ IEL亚群之间的串扰以及这如何影响增殖， 这些细胞的运动性和效应器功能。接下来，我们将确定γδ IEL的函数结果 稳态条件下上皮屏障完整性的失调。在第二个目标中，我们将研究 病毒感染后I型IFN增强γδ IEL效应子功能的机制。使用该新型 我们开创的活体显微镜技术以及我们在体外和体内之间流畅移动的能力 模型，我们将研究病原体相关的I型IFN水平诱导的分子信号， 增强γδ IEL上皮监视和激活。最后，根据γδ国际环境标志在 在肠道病原体的反应中，我们将研究I型IFN诱导的γδ IEL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基因靶向， 技术和新的模型来分析γδ IEL离体功能，我们希望定义分子 I型IFN在稳态条件下和感染期间调节γδ IEL的机制。的 拟议的研究将为调节γδ IEL激活的分子机制提供新的见解， 增强的γδ IEL效应子功能影响上皮完整性和宿主防御的程度。

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.