Traffic from chronic mycobacterium induced granulomas

描述（由申请人提供）：结核病可以潜伏数十年，全世界有数十亿人受到感染，但这是人们对该疾病知之甚少的阶段。关于分枝杆菌病原体的休眠状态以及病原体在宿主体内的适应情况的研究数据不断涌现，无论是在基因表达还是蛋白质表达水平上。同时，对潜伏期宿主免疫反应知之甚少，尤其是那些位于肉芽肿性炎症病变中的反应。硬壁肉芽肿起到防止病原体传播的作用，并保护周围的宿主组织。它在多大程度上还能保护细菌免遭灭菌免疫的影响，并可能阻止免疫系统接触病原体，目前尚不清楚。迫切需要有关针对休眠分枝杆菌的特异性免疫反应的信息。特别是，关于宿主树突细胞 (DC) 能够在多大程度上采样由休眠的肉芽肿细菌专门表达的抗原，几乎没有任何信息。同样，T 细胞对潜伏抗原的全身反应尚未得到广泛表征。我们将使用牛分枝杆菌菌株卡介苗 (BCG) 感染模型在小鼠肝脏中诱导肉芽肿。含有肉芽肿的肝片将被移植到慢性阶段的小鼠体内。通过利用位于慢性肉芽肿中的荧光标记的 DC、T 细胞和细菌，我们将追踪它们在移植物中的运输情况。通过使用基因表位标记的 BCG 和 T 细胞受体转基因小鼠的组合，我们还将测试供体来源的 DC 呈递潜在分枝杆菌抗原的能力以及 T 细胞对潜在分枝杆菌抗原的全身反应。公共卫生相关性：我们的实验将提出一个关键问题：在慢性分枝杆菌感染期间，肉芽肿隔离的细菌是否能够诱导全身性宿主免疫反应。这些实验的潜在答案可能对结核疫苗工作至关重要。这些实验将增加我们对其他传染性和自身免疫性肉芽肿性疾病及其长期免疫病理学的了解。

DESCRIPTION (provided by applicant): Tuberculosis can remain latent for decades, and billions of people worldwide are infected, yet this is the stage of the disease about which the least is known. There has been an explosion of research data about the state of dormancy of the mycobacterial pathogen and the adaption of the pathogen to residence in the host, both at the level of gene expression and protein expression. At the same time very little is known about host immune reactions during the period of latency, especially those reactions which are localized in the granulomatous inflammatory lesions. The hard walled granuloma acts to prevent the dissemination of the pathogen and also protects the surrounding host tissue. The extent to which it also shields the bacteria from sterilizing immunity and possibly prevents access of the immune system to the pathogen is unknown. There is an urgent need for information about the specific immune response against dormant mycobacteria. In particular, little to no information is available about the extent to which host dendritic cells (DC) are able to sample antigens exclusively expressed by dormant, granuloma dwelling bacteria. Similarly, the systemic response of T cells to latency antigens has not been widely characterized. We will induce granulomas in murine liver using a Mycobacterium bovis strain bacille Calmette Guirin (BCG) infection model. Liver pieces containing granulomas will be transplanted into mice at the chronic stage. By taking advantage of fluorescence-tagged DC, T cells and bacteria localized in chronic granulomas, we will trace their traffic from the transplant. By using combinations of genetically epitope-tagged BCG and T cell receptor transgenic mice we will also test the capacity of donor-derived DC to present latent mycobacterial antigens and the systemic response of T cells to latent mycobacterial antigens. PUBLIC HEALTH RELEVENCE:Our experiments will ask the key question of whether during chronic mycobacterial infection, the granuloma sequestered bacteria are able to induce a systemic host immune response or not. The potential answers from these experiments could be critically important to the tuberculosis vaccine effort. These experiments will increase our understanding of other infectious and autoimmune granulomatous diseases and their long- term immunopathologies.