How does HIV lead to increased susceptibility to tuberculosis?

 描述(由申请人提供)：世卫组织最近的报告指出，结核分枝杆菌(Mtb)是感染人类免疫缺陷病毒(HIV)的个人的最大死亡原因，HIV是一种在撒哈拉以南非洲高度流行的混合感染状态。对结核病感染的敏感性似乎比通过耗尽CD4+T细胞而失去监测要复杂得多。在初步实验中，我们证明了巨噬细胞中结核分枝杆菌的复制通过与艾滋病毒的混合感染而增强。我们建议在纽约伊萨卡的康奈尔大学对实验性联合感染进行广泛的细胞和分子分析。此外，我们在马拉维布兰太尔的伊丽莎白女王中心医院(QECH)有一个艾滋病毒研究队列，并将通过分析艾滋病毒感染者肺部的巨噬细胞和淋巴细胞来探索体外表型的相关性。目前的研究建立在一种假设的基础上，即肺泡巨噬细胞的HIV感染在增加活动性结核病的易感性方面起着重要作用。具体目标1.艾滋病毒感染如何促进结核分枝杆菌的细胞内生长？是什么导致宿主细胞的通透性增加？为了阐明艾滋病毒感染促进细菌存活的机制(S)，我们针对以下三个问题：i.结核分枝杆菌的生长优势是否仅限于艾滋病毒感染的细胞？二、HIV感染是否调节巨噬细胞的杀微生物活性？三、在巨噬细胞环境中，什么样的HIV开放阅读框介导了这种改变？B.Mtb如何利用这种增加的放任性？我们建议用有偏和无偏的基因筛查来确定HIV感染的HMDM中促进结核分枝杆菌生长所需的基因。基于改变的脂代谢有利于细菌复制的假设的有偏见的方法。二、HIV感染巨噬细胞中mtb基因的无偏转座子插入位点定位(TRASH)筛选。具体目标2.艾滋病毒如何影响肺部的免疫环境，使其更容易感染和/或发展结核病？我们将评估HIV使AM更容易受到结核分枝杆菌感染的能力。A.利用HMDM作为结核分枝杆菌存活试验的替代品B.在HIV感染的背景下，人肺泡巨噬细胞的功能表型是如何调节的？

 DESCRIPTION (provided by applicant): Recent WHO reports identify Mycobacterium tuberculosis (Mtb) as the single largest cause of death of individuals infected with the Human Immunodeficiency Virus (HIV), a co-infection state highly prevalent in Sub- Saharan Africa. Susceptibility to TB infection appears to be more complex than loss of surveillance through depletion of CD4+ T-cells. In preliminary experiments we show that replication of Mtb in macrophages is enhanced by co-infection with HIV. We propose extensive cellular and molecular analyses of experimental co- infections to be performed at Cornell University, Ithaca, NY. In addition, we have an HIV study cohort at the Queen Elizabeth Central Hospital (QECH) in Blantyre, Malawi and will probe the relevance of in vitro phenotypes through analysis of macrophages and lymphocytes from the lungs of HIV-infected individuals. This current study is founded on the hypothesis HIV infection of alveolar macrophages plays a significant role in the increased susceptibility to development of active tuberculosis. Specific Aim #1. How does HIV infection promote the intracellular growth of Mtb? A. What causes the increased permissiveness of the host cell? To elucidate the mechanism(s) by which HIV infection promotes bacterial survival we are targeting the following 3 questions: i. Is the Mtb growth advantage restricted to HIV infected cells? ii. Does HIV infection modulate the microbicidal activities of the macrophage? iii. What HIV ORFs mediate this alteration in the macrophage environment? B. How does Mtb exploit this increased permissiveness? We propose both biased and unbiased genetic screens to identify genes required for enhanced Mtb growth in HIV-infected HMDM. i. Biased approach based on the hypothesis that the altered lipid metabolism favors bacterial replication. ii. Unbiased Transposon-insertion site mapping (TraSH) screen of Mtb in HIV-infected macrophages. Specific Aim #2. How does HIV impact the immune environment of the lung to render it more permissive to infection and/or progression of tuberculosis? We will assess the capacity of HIV to render AM more permissive to infection by Mtb. A. Utilization of HMDMs as surrogates for the development of a Mtb survival assay B. How is the functional phenotype of human alveolar macrophage modulated in the context of HIV infection?