Innate Immune Responses to Mycobacteria

描述(由申请人提供)：本项目的目标是了解对分枝杆菌的先天免疫反应。与任何其他细菌病原体相比，结核分枝杆菌造成的人类死亡人数更多。它在细菌病原体中是独一无二的，因为它能够颠覆宿主防御系统，建立持续的、潜伏的感染。当宿主免疫力减弱时，分枝杆菌可能会重新激活并导致疾病。目前对细菌的致病机理或宿主反应的分子水平了解很少。有效的宿主反应可能取决于对分枝杆菌模式的识别和天然免疫反应的激活。巨噬细胞是分枝杆菌复制的场所，但也是宿主防御的中心。我们假设，在杀死分枝杆菌方面有重要的宿主因素，以及使病原体能够颠覆破坏的细菌因素。我们提出了功能性基因组和遗传学方法来识别和表征对分枝杆菌的先天免疫反应。利用果蝇吞噬细胞系，我们将建立一种基于细胞的体外实验，以研究分枝杆菌对巨噬细胞的感染。我们提出了一种全基因组分析，使用基于细胞的分析和基于RNA干扰(RNAi)的方法，来确定在分枝杆菌进入吞噬细胞和在吞噬细胞内生存的重要宿主因素。将进行二次检测，以表征宿主因素在感染过程中的作用及其与细菌毒力因素的关系。将进行微阵列实验，以表征果蝇巨噬细胞对分枝杆菌的反应所激活的信号通路。我们将检查我们在RNAi筛选和微阵列分析中确定的宿主因素，以确定它们在苍蝇和哺乳动物巨噬细胞中分枝杆菌感染中的作用。该项目在哈佛医学院的诺伯特·佩里蒙博士和哈佛大学公共卫生学院的埃里克·鲁宾博士的实验室进行，将使候选人能够建立一个独立的实验室，研究结核分枝杆菌感染的发病机制，重点是宿主的先天性免疫反应。

DESCRIPTION (provided by applicant): The goal of this project is to understand innate immune responses to mycobacteria. Mycobacterium tuberculosis is responsible for more human deaths than any other bacterial pathogen. It is unique among bacterial pathogens in that it is able to subvert host defenses and establish persistent, latent infection. When host immunity wanes, the mycobacteria can reactivate and cause disease. There is little molecular understanding of bacterial pathogenesis or host responses. Effective host responses likely depend upon recognition of mycobacterial patterns and activation of innate immune responses. Macrophages serve as the site for mycobacterial replication but also are central to host defense. We hypothesize that there are host factors important in killing mycobacteria, as well as bacterial factors that enable the pathogen to subvert destruction. We propose functional genomic and genetic approaches to identify and characterize innate immune responses to mycobacteria. Using Drosophila phagocytic cell lines, we will develop an in vitro cell based assay to study mycobacterial infection of macrophages. We propose a genome-wide analysis, using the cell-based assay and an RNA interference (RNAi)-based approach, to identify host factors important in mycobacterial entry into and survival within phagocytes. Secondary assays will be done to characterize the role of the host factors during infection and their relationship to bacterial virulence factors. Microarray experiments will be done to characterize signaling pathways that are activated in Drosophila macrophages in response to mycobacteria. We will examine the host factors that we identify in RNAi screens and microarray analysis for their role in mycobacterial infections in flies and in mammalian macrophages. This project, carried out in the laboratories of Dr. Norbert Perrimon at Harvard Medical School and Dr. Eric Rubin at the Harvard School of Public Health, will enable the candidate to establish an independent laboratory studying pathogenesis of M. tuberculosis infection with a focus on host innate immune responses.