Natural killer cell-derived IL-10 and immunity to Listeria

描述(申请人提供)：单核细胞增多性李斯特氏菌(Lm)是最致命的食源性病原体之一，在免疫受损时尤其危险。李斯特氏菌是如何致病的，为什么在一些人群中易感性增加，人们仍然知之甚少。在感染期间，李斯特菌和其他微生物可以启动宿主反应，抑制而不是促进保护性免疫。识别微生物如何抑制宿主免疫是我们理解宿主-病原体相互作用和设计治疗感染的方法不可或缺的一部分。初步数据表明，LM诱导依赖自然杀伤(NK)细胞的系统性IL-10反应，限制细菌清除。这项建议的目的是研究NK细胞IL-10的诱导产生，并确定NK细胞依赖的IL-10如何限制对LM的保护性免疫。首先，将探讨依赖于NK细胞的IL-10在LM感染背景下的刺激作用。IL-18有助于早期NK细胞干扰素-γ的产生，其对NK细胞依赖的IL-10表达的影响将使用共培养系统(与纯化的NK细胞和IL-10-/-树突状细胞)结合对IL-18无反应的小鼠的病毒感染来确定。早期NK细胞干扰素-γ也可能影响随后IL-10的产生。依赖于NK细胞的干扰素-γ和IL-10之间的反馈调节的可能性将通过将对干扰素-γ或IL-10无效的小鼠的NK细胞转移到感染了LM的宿主中来研究。在拟议工作的后半部分，将研究依赖NK细胞的IL-10对保护性免疫的影响。免疫细胞亚群对IL-10无反应的小鼠将被感染LM，以确定IL-10介导的敏感性所需的细胞类型。最后，NK细胞依赖的影响 在野生型小鼠和IL-10-/-小鼠身上，通过检测在LM感染期间CD8+T细胞的细胞毒作用，将在体内评估IL-10对免疫细胞保护活性的影响。总的来说，这些实验 将探索LM诱导的NK细胞IL-10产生的要求，并确定这种反应如何影响宿主保护性免疫。这项工作将扩大我们关于微生物如何在感染期间抑制宿主免疫的知识，这对免疫反应被不适当激活的一些疾病具有广泛的影响。

DESCRIPTION (provided by applicant): The bacterium Listeria monocytogenes (Lm) is one of the most deadly foodborne pathogens, and is particularly dangerous in the immune compromised. How Listeria causes disease and why there is increased susceptibility in some populations remains poorly understood. During infection, Listeria and other microbes can initiate host responses that suppress, rather than contribute to, protective immunity. Identifying how microbes inhibit host immunity is integral to our understanding of host-pathogen interactions and the design of therapies to treat infection. Preliminary data suggest that Lm induces a natural killer (NK) cell-dependent, systemic IL-10 response that limits bacterial clearance. The goals of this proposal are to investigate the induction of NK cell IL-10 production and determine how NK cell-dependent IL-10 limits protective immunity to Lm. First, the stimulation of NK cell-dependent IL-10 in the context of Lm infection will be explored. The effect of IL-18, which contributes to early NK cell IFN-γ production, on NK cell-dependent IL-10 expression will be determined using a co-culture system (with purified NK cells and IL-10-/- dendritic cells) in conjunction with in vio infections in mice that are unresponsive to IL-18. It is also possible that early NK cell IFN-γ affects subsequent IL-10 production. The potential for feedback regulation between NK cell-dependent IFN-γ and IL-10 will be investigated by transferring NK cells from mice that are unresponsive to either IFN-γ or IL-10 into Lm-infected hosts. In the second half of the proposed work, the impact of NK cell-dependent IL-10 on protective immunity will be investigated. Mice with immune cell subsets that are unresponsive to IL-10 will be infected with Lm to determine the cell types required for IL-10-mediated susceptibility. Finally, the impact of NK cell-dependent IL-10 on immune cell protective activity will be evaluated in vivo by measuring CD8+ T cell cytotoxicity during Lm infection in wild-type versus IL-10-/- mice. Collectively, these experiments will explore the requirements for Lm-induced NK cell IL-10 production and establish how this response impacts host protective immunity. This work will expand our knowledge about how microbes can suppress host immunity during infection, which has broad implications for a number of diseases in which the immune response is inappropriately activated.