Recruitment of CX3CR1-GFP+ monocytes during Schistosoma mansoni infection.

性状（由申请方提供）：巨噬细胞（MF）对病原体免疫、组织稳态和免疫调节至关重要。蠕虫感染、变态反应和组织损伤可诱导选择性激活巨噬细胞（AAMF）分化，AAMF在促进组织重塑、创伤修复、T辅助细胞2（TH 2）分化和寄生虫清除等方面具有重要作用。AAMF的分化过程和细胞前体仍然知之甚少。最近，已经描述了单核细胞的两个功能不同的亚群及其特性;（1）Ly-6C+“炎性”单核细胞和（2）Ly 6C-“驻留”单核细胞。虽然Ly 6C-单核细胞填充正常组织，但它们也显示出巡逻血管并迅速外渗到发炎或感染的组织中以促进炎症的消退。Ly 6C-细胞在CX 3CR 1-GFP报告小鼠中也是CX 3CR 1-GFPhi，并且在心肌梗死和细菌感染的模型中得到了最好的表征。在两种模型中，外渗的Ly 6C-、CX 3CR 1-GFPhi单核细胞具有AAMF的特征，并且可以促进组织重塑、伤口愈合和免疫调节。 我们以前已经表明，蠕虫感染有力地诱导AAMF的招聘。其他研究表明，招募AAMF对保护S至关重要。从急性免疫病理学上观察感染mansoni的小鼠对虫卵的反应。我们最近还表明，无菌组织损伤可以诱导AAMF的招聘在没有感染的情况下，通过T细胞非依赖性先天免疫途径。我们现在已经进行了初步的流式细胞术，共聚焦显微镜和活体成像研究的肝肉芽肿的S。mansoni感染的CX 3CR 1-GFP/+小鼠，这表明AAMF是CX 3CR 1-GFPhi，并且可能来自巡逻窦状血管的Ly 6C-、CX 3CR 1-GFPhi单核细胞。 在这个建议中，我们建议使用活体显微镜观察T细胞-巨噬细胞的相互作用，在肝肉芽肿的S。mansoni感染的小鼠。具体来说，我们建议测试的假设，AAMF招募的S。曼氏卵从CX 3CR 1-GFPh 1、Ly 6C-单核细胞分化。作为第二个假设，我们提出，CD 4 + T细胞可能在招募或维持CX 3CR 1-GFP+细胞进入肉芽肿分化为AAMF在慢性感染过程中发挥作用。因此，我们的具体目标是：（1）使用CX 3CR 1- GFP报告小鼠观察肝肉芽肿中单核细胞募集和巨噬细胞分化的动态;（2）确定CD 4 + TH 2细胞在S.肝脏肉芽肿中有曼氏虫卵这些研究将提高我们对Th 2条件下单核细胞募集和巨噬细胞分化的理解，并可能为我们提供一个新的干预疗法来调节致病性炎症Th 2反应的框架。 公共卫生相关性：在辅助性T细胞2型条件下激活的巨噬细胞在伤口愈合、过敏反应和寄生虫感染中是重要的。这些细胞是如何从血液中的单核细胞募集到组织中的尚不清楚。该项目的目标是确定这些巨噬细胞来自哪里，以便设计干预策略，帮助调节2型反应期间的炎症过程。

DESCRIPTION (provided by applicant): Macrophages (MF) are essential for immunity against pathogens, tissue homeostasis and immune regulation. Helminth infections, allergic reactions and tissue injury can induce the differentiation of alternatively activated macrophages (AAMF), which are important in promoting tissue remodeling, wound repair, T helper 2 (TH2) differentiation and parasite clearance. The differentiation process and cellular precursors of AAMF remains poorly understood. Recently, two functionally distinct subsets of monocytes and their properties have been described; (1) Ly-6C+ "inflammatory" monocytes and (2) Ly6C- "resident" monocytes. While Ly6C- monocytes populate normal tissues, they have also been shown to patrol blood vessels and extravasate rapidly into inflamed or infected tissues to promote the resolution of inflammation. Ly6C- cells are also CX3CR1-GFPhi in a CX3CR1-GFP reporter mouse and have been best characterized in models of myocardial infarction and bacterial infection. In both models, extravasated Ly6C-, CX3CR1-GFPhi monocytes have characteristics of AAMF and can promote tissue remodeling, wound healing and immune modulation. We have previously shown that helminth infection potently induces recruitment of AAMF. Others have shown that the recruitment of AAMF is critical in protecting S. mansoni infected mice from acute immunopathology in response to the eggs. We have also recently shown that sterile tissue injury can induce recruitment of AAMF in the absence of infection, through a T cell independent innate immune pathway. We have now conducted preliminary flow cytometry, confocal microscopy and intra-vital imaging studies of the liver granulomas of S. mansoni infected CX3CR1-GFP/+ mice, which suggest that AAMF are CX3CR1-GFPhi and may arise from the Ly6C-, CX3CR1-GFPhi monocytes that are patrolling the sinusoidal vessels. In this proposal, we propose to use intra-vital microscopy to observe T cell-macrophage interactions in the liver granulomas of S. mansoni infected mice. Specifically, we propose to test the hypothesis that AAMF recruited by S. mansoni eggs differentiate from CX3CR1-GFPhi, Ly6C- monocytes. As a secondary hypothesis, we propose that CD4+ T cells may play a role in recruiting or maintaining CX3CR1-GFP+ cells into the granulomas to differentiate into AAMF during chronic infection. Therefore, our specific aims are: (1) to visualize the dynamics of monocyte recruitment and macrophage differentiation in liver granulomas using the CX3CR1- GFP reporter mice; (2) to determine the role of CD4+ TH2 cells in the recruitment of CX3CR1-GFPhi cells by S. mansoni eggs in the liver granulomas. These studies will improve our understanding of monocyte recruitment and macrophage differentiation under Th2 conditions and may provide us with a framework for new interventional therapies to regulate pathogenic inflammatory Th2 responses. PUBLIC HEALTH RELEVANCE: Macrophages activated under T helper type 2 conditions are important in wound healing, allergic reactions and parasite infections. How these cells are recruited into the tissues from monocytes in the blood is not clear. The goal of this project is to identify where these macrophages come from in order to design interventional strategies that could help regulate the inflammatory process during a type 2 response.