Macrophage defense againt M. tuberculosis

描述（由申请人提供）：结核病是全球感染死亡的主要原因。结核分枝杆菌（Mtb）和人类巨噬细胞之间的相互作用的研究是了解结核病发病机制的基础。免疫刺激DNA序列及其合成的寡核苷酸类似物（CpG-ODN）已被证明在体外和体内发挥抗菌作用，并且我们发现CpG-ODN激活人单核细胞衍生的巨噬细胞（hMDM）中的抗分枝杆菌活性。该K 08项目的目标是更全面地表征这种CpG-ODN效应的机制和幅度。实验将确定抗分枝杆菌应答是否通过TLR 9激活，TLR 9是已知由CpG-ODN激活的唯一受体。虽然鼠巨噬细胞可以被干扰素（IFN）-γ激活以在体外杀死细胞内分枝杆菌，但是我们和其他人已经发现IFN-γ矛盾地增强病原体的细胞内生长。人巨噬细胞抑制结核分枝杆菌的机制尚不清楚，通过阐明CpG-ODN激活的机制可能会获得新的知识。我们将确定这种反应是否广泛适用于不同的Mtb菌株，以及hMDM和人肺泡巨噬细胞（体内Mtb感染的初始宿主细胞）的活性之间是否存在差异。我们还将测试巨噬细胞样细胞系（THP-1）是否可用于模拟CpG-ODN反应，因为这些细胞将有助于Toll依赖性信号传导的分子研究。这种CpG-ODN效应机制的线索将在巨噬细胞活化和信号传导的功能研究中寻找，并使用微阵列广泛地询问刺激细胞的转录组。最后，我们将比较通过不同的Toll受体与一组配体的刺激效果，以寻找与CpG-ODN相比的相似性或差异性，并确定潜在的协同作用。这些研究将为人类巨噬细胞的先天性抗分枝杆菌功能提供新的基础知识，并为发现结核病的新免疫策略提供合理的基础。

DESCRIPTION (provided by applicant): Tuberculosis is a leading cause of death from infection worldwide. Investigations of interactions between Mycobacterium tuberculosis (Mtb) and human macrophages are fundamental for understanding tuberculosis pathogenesis. Immunostimulatory DNA sequences and their synthetic oligonucleotide analogs (CpG-ODN) have been shown to exert antibacterial effects in vitro and in vivo, and we discovered that CpG-ODN activate anti-mycobacterial activity in human monoeyte-derived macrophages (hMDM). The goals of this K08 project are to more fully characterize the mechanism(s) and magnitude of this CpG-ODN effect. Experiments will determine whether anti-mycobacterial responses are activated thorugh TLR9, the only receptor known to be activated by CpG-ODN. While murine macrophages can be activated by interferon (IFN)-gamma to kill intracellular mycobacteria in vitro, we and others have found that IFN-gamma, paradoxically potentiates intracellular growth of the pathogen. The mechanisms whereby human macrophages restrict Mtb remain uncertain, and new knowledge may be gained through delineating the mechanisms acitvated by CpG-ODN. We will determine if this response is broadly applicable to different Mtb strains, and if there are differences between the activity of hMDM and human alveolar macrophages (the initial host cell infected by Mtb in vivo). We will also test whether macrophage-like cell lines (THP-1) can be used to model the CpG-ODN response, since these cells would facilitate molecular studies of Toll-dependent signaling. Clues to the mechanism of this CpG-ODN effect will be sought in functional studies ofmacrophage activation and signaling, and using microarrays to interrogate the transcriptome of stimulated cells broadly. Finally, we will compare the effects of stimulation through different Toll receptors with a panel of ligands to look for similarities or differences compared with CpG-ODN, and to identify potential synergies. These studies will provide new basic knowledge of the innate anti-mycobacterial functions of human macrophages, and they will provide a rational basis for the discovery of new immunotherapeutic strategies for tuberculosis.