Mycobacterium tuberculosis cell wall virulence factors

描述（由申请人提供）：结核病（TB）每年造成约300万人死亡。M.结核分枝杆菌的一个重要特征是其在人类巨噬细胞内存活的能力，并且分枝杆菌细胞壁成分是这种效应的可能介质。然而，很少有人知道特定的细胞壁成分的作用，无论是在宿主巨噬细胞内的分枝杆菌的生存或调节巨噬细胞对分枝杆菌感染的反应。在我们的实验室中，最近一代的M。结核病转座子介导的突变体库提供了一个独特的机会，系统地研究这些问题。我们的总体目标是了解M的作用。结核细胞壁成分在结核病发病机制中的作用。我们的假设是M.结核病细胞壁组分调节巨噬细胞免疫应答，并且细胞壁的改变将影响巨噬细胞对分枝杆菌的应答。该R 03提案的具体目的是表征人巨噬细胞对a）感染M.预测在细胞壁中具有改变的结核病转座子介导的突变体，和B）用来自这些突变体的细胞壁级分刺激。将使用已知或预测参与硫脂、脂阿拉伯甘露聚糖、分枝菌酸和邻苯二甲酸二霉菌蜡酯生物合成的基因被破坏的突变体。将表征宿主细胞细胞因子产生、趋化因子产生、细胞凋亡、IFN γ介导的应答和toll样受体介导的应答，并确定巨噬细胞内分枝杆菌的存活和生长。这项研究将有助于更好地了解分枝杆菌细胞壁成分如何影响细菌-宿主细胞相互作用，并有助于确定新的抗结核药物靶点和疫苗策略。如果细胞壁组分对M.因此，如果结核病引起的免疫抑制没有发生，那么就有必要评价适当的突变菌株作为疫苗。这些研究也将作为快速体外筛选系统的发展，以评估其他M的影响的基础。结核病基因或细胞组分对靶向宿主免疫应答的影响。最后，从拟议的自包含的试点研究的新信息将作为基础，为未来的巨噬细胞反应途径的具体细胞壁成分的影响进行全面解剖。

DESCRIPTION (provided by applicant): Tuberculosis (TB) kills approximately 3 million people per year. An important characteristic of M. tuberculosis is its ability to survive within human macrophages, and mycobacterial cell wall components are plausible mediators of this effect. However, little is known about the role of specific cell wall components in either mycobacterial survival within host macrophages or modulation of macrophage responses to mycobacterial infection. In our laboratory, the recent generation of a M. tuberculosis transposon-mediated mutant library provides a unique opportunity to systematically investigate these issues. Our overall objective is to understand the role of M. tuberculosis cell wall components in the pathogenesis of TB. Our hypothesis is that M. tuberculosis cell wall components modulate macrophage immune responses, and that alteration of the cell wall will affect macrophage responses to mycobacteria. The specific aim of this R03 proposal is to characterize human macrophage responses to a) infection with M. tuberculosis transposon-mediated mutants predicted to have alterations in the cell wall, and b)stimulation with cell wall fractions from those mutants. Mutants with disruptions in genes known or predicted to be involved in biosynthesis of sulfolipids, lipoarabinomannan, mycolic acids, and phthiocerol dimycocerosate will be used. Host cell cytokine production, chemokine production, apoptosis, IFN gamma-mediated responses, and toll-like receptor-mediated responses will be characterized, and mycobacterial survival and growth within macrophages will be determined. This research will lead to a better understanding of how mycobacterial cell wall components affect bacteria-host cell interactions, and will facilitate identification of new anti-tuberculosis drug targets and vaccine strategies. If cell wall components contribute to M. tuberculosis-induced immune suppression, then evaluation of appropriate mutant strains as vaccines would be warranted. These studies will also serve as a foundation for development of rapid in vitro screening systems to evaluate the effects of other M. tuberculosis genes or cellular components on targeted host immune responses. Finally, new information from the proposed self-contained pilot studies will serve as the foundation for future comprehensive dissection of macrophage response pathways affected by specific cell wall components.