Apoptotic T Cell Clearance From Murine Lungs

描述(申请人摘要)：必须清除凋亡的T细胞 巨噬细胞有效地防止组织损伤，但吞噬细胞凋亡 细胞使巨噬细胞下调其自身产生的 促炎细胞因子，如肿瘤坏死因子和白介素8，以及趋化因子。因此，虽然 在肺炎消退期间摄取凋亡的T细胞是有益的，同样 如果肺泡巨噬细胞吞噬，过程可能是免疫抑制的 在与病原体接触之前或期间死亡的T细胞。事实上，研究 由该项目资助的一项新的观察发现，许多细胞凋亡 淋巴细胞存在于小鼠的肺中。因此，肺是一种粘膜表面 经常接触病原体，在监管方面提出了独特的挑战 巨噬细胞清除凋亡的T细胞，同时维持宿主防御。它是 很可能这一挑战既与正常状态相关，在正常状态下 单个肺泡巨噬细胞遇到孤立的凋亡T细胞，当 大量T细胞死亡(例如，在急性病毒性肺炎和 慢性艾滋病毒感染)。来自该项目的新的初步数据表明 肺巨噬细胞对凋亡T细胞的摄取受到调控，作为一种 进化适应，以最大限度地减少免疫抑制效应 否则会在这个经常接触病原体的地方造成。这样做的目的是 项目是定义调控的分子基础和意义 肺内T细胞凋亡的吞噬作用。它将测试以下内容 假设：居民对凋亡T细胞的吞噬功能下调 小鼠肺泡巨噬细胞与凋亡T细胞黏附改变 细胞和信号转导相对于对照腹膜改变 巨噬细胞；在分解过程中有效清除凋亡的T细胞 肺部炎症可能取决于摄取表型的获得。 主要是通过炎性细胞因子分化招募的单核细胞；以及 摄取凋亡的T细胞存在肺宿主受损的风险 对细菌和真菌病原体的防御。均为原发驻留肺泡 和正常小鼠的腹膜巨噬细胞，以及两只永生化的小鼠 将使用巨噬细胞系(MH-S和J774A.1)。技术将包括 静态黏附和吞噬试验，特异性酶抑制剂， 免疫沉淀、免疫印迹、流式细胞术和体内应用 真菌(新生隐球菌)和细菌(葡萄球菌)的小鼠模型 肺炎。预计结果将提供重要的 有关免疫调节的新信息将与病毒相关， 正常和免疫受损宿主的细菌和真菌感染， 自身免疫与肺纤维化的发展。

DESCRIPTION (Applicant's Abstract): Apoptotic T cells must be cleared efficiently by macrophages to prevent tissue damage, but ingestion of apoptotic cells causes macrophages to downregulate their own production of proinflammatory cytokines such as TNF and IL-8 and of chemokines. Hence, while ingesting apoptotic T cells during resolving pneumonia is beneficial, the same process could be immunosuppressive if pulmonary alveolar macrophages ingest dying T cells before or during encounters with pathogens. Indeed, studies funded by this project made the novel observation that many apoptotic lymphocytes are found in the lungs of mice. Thus, the lungs, a mucosal surface frequently exposed to pathogens, present a unique challenge in regulating macrophage clearance of apoptotic T cells while maintaining host defense. It is likely that this challenge is relevant both to the normal state, in which single alveolar macrophages encounter isolated apoptotic T cells, and when larger numbers of T cells die (e.g., following acute viral pneumonias and in chronic HIV infection). New preliminary data from this project suggest that ingestion of apoptotic T cells by lung macrophages is regulated, as an evolutionary adaptation, to minimize the immunosuppressive effect that could otherwise result at this site of frequent pathogen exposure. The goal of this project is to define the molecular basis and significance of regulated phagocytosis of apoptotic T cells in the lungs. It will test the following hypotheses: that downregulated phagocytosis of apoptotic T cells by resident murine alveolar macrophages results both from altered adhesion of apoptotic T cells and from altered signal transduction relative to control peritoneal macrophages; that effective clearance of apoptotic T cells during resolving lung inflammation depends on acquisition of an ingesting phenotype, probably mostly by differentiation of recruited monocytes by inflammatory cytokines; and that ingestion of apoptotic T cells carries a risk of impaired lung host defense against bacterial and fungal pathogens. Both primary resident alveolar and peritoneal macrophages from normal mice, and two immortalized murine macrophage cell lines (MH-S and J774A.1) will be used. Techniques will include static adhesion and phagocytosis assays, specific enzyme inhibitors, immunoprecipitation, Western blotting, flow cytometry, and use of in vivo murine models of fungal (Cryptococcus neoformans) and bacterial (Staphylococcus aureus) pneumonia. It is anticipated that the results will provide important new information about immunoregulation that will be relevant to viral, bacterial, and fungal infections in normal and immunocompromised hosts, development of autoimmunity and lung fibrosis.