Laboratory of Mycobacterial Immunity and Pathogenesis, The Public Health Research Institute Center at the University of Medicine and Dentistry of New Jersey, Newark, USA.
Am J Pathol. 2012 Nov;181(5):1711-24. doi: 10.1016/j.ajpath.2012.07.019. Epub 2012 Sep 5.
Mycobacterium tuberculosis (Mtb), the causative agent of tuberculosis (TB), is an exquisitely adapted human pathogen capable of surviving for decades in the lungs of immune-competent individuals in the absence of disease. The World Health Organization estimates that 2 billion people have latent TB infection (LTBI), defined by a positive immunological response to Mtb antigens, with no clinical signs of disease. A better understanding of host and pathogen determinants of LTBI and subsequent reactivation would benefit TB control efforts. Animal models of LTBI have been hampered generally by an inability to achieve complete bacillary clearance. Herein, we have characterized a rabbit model of LTBI in which, similar to most humans, complete clearance of pulmonary Mtb infection and pathological characteristics occurs spontaneously. The evidence that Mtb-CDC1551-infected rabbits achieve LTBI, rather than sterilization, is based on the ability of the bacilli to be reactivated after immune suppression. These rabbits showed early activation of T cells and macrophages and an early peak in the TNFα level, which decreased in association with clearance of bacilli from the lungs. In the absence of sustained tumor necrosis factor-α production, no necrosis was seen in the evolving lung granulomas. In addition, bacillary control was associated with down-regulation of several metalloprotease genes and an absence of lung fibrosis. This model will be used to characterize molecular markers of protective immunity and reactivation.
结核分枝杆菌(Mtb)是结核病(TB)的病原体,是一种高度适应的人类病原体,能够在免疫功能正常的个体肺部中存活数十年而不发病。世界卫生组织估计,有 20 亿人患有潜伏性结核感染(LTBI),其定义为对 Mtb 抗原的免疫反应阳性,但没有疾病的临床迹象。更好地了解 LTBI 及随后再激活的宿主和病原体决定因素将有益于结核病控制工作。LTBI 的动物模型通常受到无法完全清除细菌的阻碍。在此,我们描述了一种兔 LTBI 模型,类似于大多数人类,肺部 Mtb 感染和病理特征的完全清除会自发发生。Mtb-CDC1551 感染的兔子实现 LTBI 而不是灭菌的证据基于细菌在免疫抑制后能够重新激活的能力。这些兔子显示出 T 细胞和巨噬细胞的早期激活,以及 TNFα 水平的早期峰值,该峰值随着肺部细菌的清除而降低。由于没有持续产生肿瘤坏死因子-α,在不断发展的肺部肉芽肿中没有看到坏死。此外,细菌的控制与几种金属蛋白酶基因的下调以及没有肺纤维化有关。该模型将用于描述保护性免疫和再激活的分子标志物。