Host-Directed Therapy to Augment anti-M. tuberculosis Responses in the Setting of HIV Co-infection and to Sterilize the Tuberculoma

摘要： 结核分枝杆菌(Mtb)感染可导致结核病(TB)，造成约900万新病例 全球每年约有180万人感染和死亡。其中四分之一是死于结核病/艾滋病 由结核分枝杆菌/艾滋病毒混合感染和由此导致的肺结核病重新激活引起的共病。结核病在中国的死灰复燃 过去20年可以归因于卡介苗(BCG)抗结核疫苗的失败 含有成人、肺结核病以及出现抗药性和艾滋病大流行。失败者 控制结核病源于对其毒力和致病程序缺乏完整的了解 被这种高度专门化和成功的病原体利用，以便在宿主的肺部持续存在。作为以下内容的一部分 在其毒力循环中，结核分枝杆菌调节宿主免疫。 我们利用结核分枝杆菌的自然感染途径，建立了一种稳健的Mtb/HIV混合感染猕猴模型。 并使用猿猴免疫缺陷病毒(SIV)作为HIV的替代品。此模式可用于 在真实的体内环境中研究结核分枝杆菌的生理学。利用我们的模型，我们证明了IDO的表达式 (INDO，IDO1)，一种激活的CD4+T细胞的强大免疫抑制剂，在肺中显著增强 猕猴肉芽肿。在髓系细胞中，IDO水平是以细菌负荷特异性的方式诱导的。 因此，将吸入性结核分枝杆菌感染控制为LTBI的猕猴，在肺部病变中不表达高水平的IDO， 但那些晋级ATB的人会这样做。当患有ATB的动物接受化疗时，IDO水平下降 治疗过了。当与SIV混合感染时，携带LTBI的猕猴中有2/3的人重新激活了疾病-只有这些动物 表现为肺IDO诱导。最后，非致病性感染结核分枝杆菌无毒突变株未能诱导 诱导IDO。FDA批准的体内安全化合物改善IDO酶活性 在显著减少结核病的临床体征、病理和细菌负担方面，并提高存活率。这是 伴有肺T细胞增殖增加和支气管相关淋巴组织的诱导 (IBALT)这些事件重塑肉芽肿有两种不同的方式：一)治疗后功能性肉芽肿 (IDO阻断)动物没有表现出T细胞耗尽的迹象，而是表现出更高的T细胞表达 分化、凋亡、杀菌和肺组织重塑途径；ii)在形态上， T细胞向肉芽肿中心移位。对Mtb的更好的杀戮 由CD4+T细胞产生的巨噬细胞可以在体外模拟一种新的猕猴巨噬细胞：CD4+T细胞共... 文化体系。我们的结果有力地表明IDO调节一种复杂的免疫/代谢信号 促进细菌存活、免疫功能障碍和疾病的网络。因此，抑制IDO是一个质数 针对耐多药结核病流行的辅助性HDT的目标。 根据这些数据，我们推测IDO1信号是调节类人免疫反应的关键 肺部肉芽肿。我们现在建议利用LTBI的猕猴模型来研究IDO-阻断体内 可增强肉芽肿性能，杀灭结核杆菌感染。将使用SIV联合感染来测试这一点。 最后，我们将用肠道归巢T细胞阻断A4b7抗体来治疗Mtb/SIV共同感染的动物，除了 封锁IDO。我们推测，这种双重治疗将减少病毒载量，从而防止重新激活， 增强IDO封闭剂的杀菌潜力。

Abstract  Mycobacterium tuberculosis (Mtb) infection can lead to tuberculosis (TB) disease, causing ~9 million new infections and ~1.8 million deaths globally, every year. A quarter of these are deaths due to the TB/AIDS comorbidity, caused by Mtb/HIV co-infection and the resulting reactivation of LTBI. The resurgence of TB in the last two decades can be attributed to the failure of the anti-TB vaccine, Bacille Calmette-Guerin (BCG) in containing adult, pulmonary TB as well, the emergence of drug-resistance and the AIDS pandemic. The failure to control TB stems from the lack of complete understanding of the virulence and pathogenesis programs utilized by this highly specialized and successful pathogen in order to persist in the lungs of its hosts. As part of its virulence cycle, Mtb modulates host immunity. We have developed a robust macaque model Mtb/HIV co-infection, by using natural routes of Mtb infection and by using Simian Immunodeficiency Virus (SIV) as a surrogate for HIV. This model can be leveraged to study the physiology of Mtb in a true in-vivo setting. Using our model, we show that the expression of IDO (INDO, IDO1), a powerful immunosuppressant of activated CD4+ T cells, is dramatically enhanced in the lung granulomata of macaques. Levels of IDO are induced in a bacterial burden specific manner in myeloid cells. Thus, macaques that control inhaled Mtb infection as LTBI, do not express high levels of IDO in lung lesions, but those that progress to ATB do. IDO levels decline when animals with ATB are chemotherapeutically treated. Upon co-infection with SIV, 2/3rds of the macaques with LTBI reactivate disease - only these animals exhibited lung IDO induction. Finally, nonpathogenic infection with avirulent mutants of Mtb failed to elicit the induction of IDO. Amelioration of IDO enzymatic activity by an FDA, approved, safe compound in-vivo resulted in significant reduction in clinical signs of TB, pathology and bacterial burden, and increased survival. This was accompanied by increased lung T cell proliferation and induction of bronchus associated lymphoid tissue (iBALT). These events reshaped the granuloma is two different ways: i) functionally granulomas from treated (IDO blockaded) animals exhibited no signatures of T cell exhaustion but instead higher expression of T cell differentiation, apoptosis, bacterial killing and lung tissue remodeling pathways; ii) morphologically, greater relocation of T cells was observed to the center of the granulomata. The profoundly better killing of Mtb in macrophages by CD4+ T cells could be modeled in-vitro, in a novel macaque macrophage:CD4+ T cell co- culture system. Our results strongly suggest that IDO modulates a complex immune/metabolic signaling network that promotes bacterial survival, immune dysfunction and disease. Thus, inhibition of IDO is a prime target for adjunctive HDT against the multidrug resistant TB epidemic. Based on these data, we postulate that IDO1-signaling is key to modulating immune responses in human-like lung granulomas. We now propose to leverage the macaque model of LTBI to study if IDO-blockade in-vivo can enhance granuloma performance and sterilize Mtb infection. SIV co-infection will be used to test this. Finally, we will treat Mtb/SIV co-infected animals with a gut homing T cell blocking a4b7 antibody in addition to blockading IDO. We postulate that this dual treatment will reduce the viral load thus preventing reactivation, and enhance the sterilizing potential of IDO blockade.