Host Responses to Mycobacterium Infection in Zebrafish

描述(申请人提供)：结核病是全世界传染病死亡的主要原因，由于艾滋病毒流行，其后果越来越严重。感染和疾病是由细胞内的结核分枝杆菌引起的。现有的BCG疫苗疗效有限，药物治疗漫长而复杂，导致不依从性和多重耐药细菌的快速传播。此外，在发达国家，越来越多地使用肿瘤坏死因子受体阻滞剂治疗风湿病和免疫学疾病，导致这些患者中结核病的激活。面对复杂的免疫反应，分枝杆菌可以无限期地存活在肉芽肿、高度分化的巨噬细胞和其他免疫细胞的紧密聚集中。与大多数传染病一样，宿主免疫的不同组成部分对结核病感染和疾病的确切影响尚不清楚。为了更好地了解宿主对结核感染的反应，我们将利用海洋分枝杆菌是结核分枝杆菌的近亲，是斑马鱼的天然病原体，导致一种具有人类结核病所有基本病理特征的类似结核病的疾病。斑马鱼是基因易驯化的脊椎动物，被用作疾病和发育的模型。我们利用斑马鱼胚胎和幼虫的光学透明度和遗传易感性来实时监测和调节结核病宿主与病原体的相互作用。由于我们能够对感染的各个步骤进行实时成像，我们已经能够确定关键宿主免疫决定因素(例如肿瘤坏死因子)和细菌毒力决定因素在致病过程中发挥作用的准确步骤。我们将结合各种分子和遗传技术来拦截宿主免疫功能的表达，从而通过各种实时显微镜技术来确定它们对结核病个别步骤和最终结果的影响。

DESCRIPTION (provided by applicant): Tuberculosis is the leading cause of death from infectious diseases worldwide, with increasing consequences due to the HIV epidemic. Infection and disease are caused by the intracellular bacterial pathogen Mycobacterium tuberculosis. The existing vaccine, BCG, has marginal efficacy and drug therapies are long and complex leading to noncompliance and the rapid spread of multi-drug resistant bacteria. Additionally, in the developed world, the increasing use of TNF blockade for the treatment of rheumatologic and immunological conditions has led to the activation of tuberculosis in these patients. In the face of a complex immune response, mycobacteria can persist indefinitely in granulomas, tight aggregates of highly differentiated macrophages and other immune cells. As with most infectious diseases, the exact impact of the different components of host immunity on tuberculosis infection and disease are not well understood. To better understand the host responses to tuberculous infections, we will take advantage of the fact that Mycobacterium marinum, a close relative of M. tuberculosis, is a natural pathogen of zebrafish, causing a tuberculosis-like disease with all the basic pathologic features of human tuberculosis Zebrafish are genetically tractable vertebrates that are used as models of disease and development. We have exploited the optical transparency and the genetic tractablility of zebrafish embryos and larvae to monitor and modulate host-pathogen interactions of tuberculosis in real time. Due to our ability to perform real-time imaging of the individual steps of infection, we have been able to determine the precise steps at which key host immune determinants (e.g. TNF) and bacterial virulence determinants act during pathogenesis. We will combine a variety of molecular and genetic techniques to intercept the expression of host immune functions so as to determine their impact on the individual steps and final outcomes of tuberculosis by a variety of real- time microscopy techniques.