LATENCY AND REACTIVATION TUBERCULOSIS

描述(由申请人提供)： 结核分枝杆菌以其感染人类的能力而引人注目。 主机并保持静止多年，直到主机防御时才重新激活 都被压制了。全球三分之一的人口潜伏感染 结核病，然而这种临床上不活跃的状态，当杆菌通常是非 可栽培的很少被理解，也没有充分的特征。恰如其分 需要更准确地模拟人类疾病的动物模型来进行测试 候选疫苗，并了解两者之间的复杂关系 分枝杆菌和宿主。目前可用的动物模型在小鼠和 豚鼠以多杆菌疾病为特征，并被区分开来 通过宿主的反应。小鼠表现出较差的迟发性超敏反应 并发展成慢性肺部疾病，最终死于进行性 细菌载量高的肉芽肿性肺部疾病。豚鼠也 有多杆菌病，但极易感染快速 血源性播散和强烈的DTH反应导致快速 肺部发炎、破坏和死亡。杆状芽胞杆菌潜伏病 只能通过注射抗生素来诱导。相比之下，兔子 对结核分枝杆菌的气雾剂感染具有相对抵抗力， 肉芽肿性反应，有效地遏制细菌。在整个过程中 6-12个月后，所有可培养的杆菌消失。此外， 组织病理学反应与人类所指的 兔结核病模型作为一种很有前途的研究途径 寄主和细菌的特定阶段的变化。 在这个应用程序中，我们将气雾剂感染兔子并允许 肺部肉芽肿病变消退至潜伏期。通过使用 免疫抑制剂，如皮质类固醇、iNOS抑制剂和 特异性的抗细胞因子抗体，我们会重新激活感染。同时，我们 将改进使用兔白细胞进行的体外肉芽肿检测 有一个体外模型来关联和比较我们在体内的 结果。在感染的不同阶段收集血清和兔组织，我们 将表征特定阶段的宿主体液和细胞介导的免疫 回应。了解潜伏期疾病中的抗体表达谱 可能导致对一种疾病的重要诊断，这种疾病受到 敏感性和特异度低。此外，我们还将分析 利用微阵列技术研究细菌对不同疾病阶段的转录反应 用分子信标进行RT-PCR。最后，我们将使用一个转座子突变体 文库，以识别在感染的特定阶段受损的克隆。 合适的动物模型是成功发展的关键 结核病疫苗、新药和更好的结核病诊断测试。

DESCRIPTION (provided by applicant): Mycobacterium tuberculosis is remarkable in its ability to infect the human host and remain quiescent for many years only to reactivate when host defenses are suppressed. One-third of the global population is latently infected with tuberculosis, yet this clinically inactive state when bacilli are often non- cultivatable is poorly understood and inadequately characterized. Appropriate animal models that more accurately mimic human diseases are needed to test vaccine candidates, and to understand the complex relationship between mycobacteria and host. The currently available animal models in mice and guinea pigs are characterized by multibacillary disease and are distinguished by the host response. Mice mount a poor delayed type hypersensitivity response and develop chronic lung disease, eventually succumbing to a progressive granulomatous pulmonary disease with high bacillary load. Guinea pigs also have a multibacillary disease, but are exquisitely susceptible with rapid hematogenous dissemination and a strong DTH response that results in rapid lung inflammation, destruction and death. Paucibacillary latent disease can only be induced with the administration of antibiotics. In contrast, rabbits are relatively resistant to aerosol infection with M. tuberculosis and mount a granulomatous response that effectively contains the bacilli. Over the course of 6-l2 months, all culturable bacilli disappear. In addition, the histopathologic response is remarkably similar to that of humans pointing to the rabbit model of tuberculosis as a promising avenue by which to study stage-specific changes in both host and bacilli. In this application, we will aerosol infect rabbits and allow the granulomatous lung lesions to regress to latency. With the use of immunosuppressive agents such as corticosteroids, iNOS inhibitors, and specific anti-cytokine antibody, we will reactivate infection. In parallel, we will refine the in vitro granuloma assay using rabbit white blood cells to have an in vitro model with which to correlate and compare our in vivo results. Harvesting serum and rabbit tissue at various stages of infection, we will characterize the stage-specific host humoral and cell-mediated immune responses. Understanding the antibody expression profile during latent disease may lead to important diagnostics in a disease hampered by diagnostics with low sensitivity and specificity. In addition, we will analyze the transcriptional bacterial response to various disease stages using microarrays and RT-PCR with molecular beacons. Finally, we will use a transposon mutant library to identify clones that are impaired in specific stages of infection. Appropriate animal models are critical to the successful development of tuberculosis vaccines, new drugs and better diagnostic tests for tuberculosis.