The role of innate immunity in the acquisition of sterile protection against TB infection

总结 结核病（TB）是一个主要的全球性健康问题。Bacille de Calmette et Guérin（BCG），唯一结核病 获得许可的预防性疫苗对肺外结核（extra-PTB）的有效性为80%，但 对原发性结核感染部位的PTB有效。结核病疫苗开发的一大障碍 比卡介苗更有效的是，对结核病的免疫保护还不完全清楚。卡介苗导致结核病- 特异性适应性细胞介导的免疫（aCMI），被认为特别有助于其强大的 对extra-PTB的保护作用，但不赋予对M的无菌免疫。结核病（Mtb）和 不能预防潜伏性结核感染（LTBI）。我们假设Mtb记忆样先天性CMI（iCMI）是 预防LTBI的针对原发性Mtb感染的保护机制。一个重要的推论是结核病- 特异性iCMI将为疫苗诱导的抗结核无菌保护提供强有力的措施， 开发高效结核病疫苗的工具。使用结核病队列中收集的样本 印度-美国医学合作组织多中心前瞻性观察性研究（C-TRIUMPH） 印度浦那Byramjee Jeejeebhoy政府医学院（BJMC）与一组卡介苗接种者 在美国招募的结核病暴露可忽略不计的情况下，我们将研究结核病特异性iCMI作为一种机制， 针对Mtb的无菌保护，以及BCG疫苗接种可引发Mtb记忆iCMI的程度。 AIM 1.确定区分LTBI-和LTBI+成人的Mtb iCMI特征， 涂片阳性PTBI。 假设：LTBI-高度暴露于TB的个体比LTBI+具有更强大的Mtb记忆样iCMI 个体 使用CyTOF技术和为大型数据集设计的系统生物学分析工具，我们将测量 NK、NKT、NK T和粘膜相关不变T（MAIT）细胞对离体Mtb应答的大阵列 抗原刺激，并分析高度暴露于LTBI-和LTBI+成人亚组之间的差异 涂阳创伤后损伤最显著的独立差异将用于构建较小的流 将使用流式细胞术面板来测试剩余的LTBI-和LTBI+高度TB暴露的成人。 AIM 2.表征BCG产生的Mtb特异性iCMI。 假设：与LTBI-高度暴露于TB的个体相比，BCG给药产生 记忆性iCMI对Mtb的影响较小和/或仅限于一部分疫苗接受者。 我们将招募接受BCG且结核病暴露可忽略不计的成年人，并将他们的Mtb iCMI与 使用AIM 1中描述的工具对高度TB暴露的LTBI-成人进行评估。 这项研究的结果有可能通过以下方式改变针对Mtb感染的免疫保护模式： 将iCMI替代和/或添加到aCMI中作为长期保护性反应，从而彻底改变 结核病疫苗研发领域。该研究将通过使用已收集的数据为C-TRIUMPh提供附加值。 外周血单核细胞（PBMC），以实现其免疫目标。我们还将利用 NIH努力在BJMC开发先进的免疫能力。

Summary Tuberculosis (TB) is a major global health problem. Bacille de Calmette et Guérin (BCG), the only TB prophylactic vaccine licensed, is 80% effective against extra-pulmonary TB (extra-PTB), but has variable efficacy against PTB, the site of primary TB infection. A big handicap in the development of TB vaccines more effective than BCG is that immune protection against TB is incompletely understood. BCG generates TB- specific adaptive cell-mediated immunity (aCMI), which is thought to contribute especially to its strong protective effect against extra-PTB, but does not confer sterile immunity against M. tuberculosis (Mtb) and does not protect against latent TB infection (LTBI). We hypothesized that Mtb memory-like innate CMI (iCMI) is a mechanism of protection against primary Mtb infection that prevents LTBI. An important corollary is that TB- specific iCMI will provide a robust measure for vaccine-induced sterile protection against TB, a much needed tool for the development of highly efficacious TB vaccines. Using samples collected in the Cohort For TB Research By The Indo-US Medical Partnership Multicentric Prospective Observational Study (C-TRIUMPH) at the Byramjee Jeejeebhoy Govt. Medical College (BJMC), Pune, India, together with a group of BCG recipients with negligible exposure to TB to be enrolled in the US, we will investigate TB-specific iCMI as a mechanism of sterile protection against Mtb, and the extent to which Mtb memory iCMI can be elicited by BCG vaccination. AIM 1. To identify the Mtb iCMI characteristics that differentiate LTBI- from LTBI+ adults with high exposure to smear-positive PTBI. Hypothesis: LTBI- individuals highly exposed to TB have more robust Mtb memory-like iCMI than LTBI+ individuals. Using CyTOF technology and systems biology analytical tools designed for large datasets, we will measure a large array of NK, NKT,  T and mucosal-associated invariant T (MAIT) cell responses to ex-vivo Mtb antigenic stimulation and analyze the differences between a subset of LTBI- and LTBI+ adults highly exposed to smear-positive PTBI. The most significant independent differences will be used to build a smaller flow cytometry panel that will be used to test the remaining LTBI- and LTBI+ highly TB-exposed adults. AIM 2. To characterize the Mtb-specific iCMI generated by BCG. Hypothesis: Compared with LTBI- individuals highly exposed to TB, BCG administration generates memory-like iCMI to Mtb of lower magnitude and/or restricted to a fraction of the vaccine recipients. We will recruit adults who received BCG and had negligible exposure to TB and compare their Mtb iCMI with that of highly TB-exposed LTBI- adults using the tools described in AIM 1. The results of this study have the potential to shift the paradigm for immune protection against Mtb infection by substituting and/or adding iCMI to aCMI as long term protective responses and, thereby, to revolutionize the field of TB vaccine development. The study will provide added value to C-TRIUMPh by using already collected peripheral blood mononuclear cells (PBMC) to accomplish its immunologic goals. We will also leverage the NIH efforts to develop advanced immunologic capacity at BJMC.