Molecular analysis of the adaptive immune response to tuberculosis

项目摘要 本R21的目的是应用尖端的分子免疫学技术来确定 适应性免疫反应可能防止活动性结核病感染。虽然大约 世界上1/3的人口感染结核病，绝大多数感染者保持 在他们的一生中控制潜伏的结核病感染。我们在先前的研究中已经证明， 既往接受过肺外结核治疗，并且没有残留或新感染的迹象， 与接受治疗的肺结核或接受治疗的潜伏感染的个体相比，而且这些 个体响应于感染的巨噬细胞具有较低水平的体外细胞因子产生。这 提示在易受播散性结核感染的个体中存在潜在的免疫缺陷。我们建立 尖端的分子技术，使我们能够1）单细胞分选病原体反应性T细胞2）直接 3）确定T细胞受体（TCR）α和β链的序列 4）在报告细胞系中重构α β TCR复合物以允许精细的 表位特异性作图。作为概念证明，在本申请中，我们将把这些技术应用于 来自患有潜伏性结核病的个体的外周血单核细胞的现有储存库（治疗和 未经治疗）和先前治疗过肺结核或肺外结核的个体。我们假设 TB特异性TCR多样性的增加可能与个体对潜伏感染的控制程度有关。

PROJECT SUMMARY The purpose of this R21 is to apply cutting edge molecular immunology techniques to determine the features of the adaptive immune response likely to protect against active tuberculosis infection. Although approximately 1/3 of the world’s population is infected with tuberculosis, the vast majority of infected individuals maintain control of latent TB infections throughout their lives. We have demonstrated in prior studies that individuals with prior treated extrapulmonary TB, and no sign of residual or new infection, have increased levels of immune activation compared to individuals with treated pulmonary TB, or treated latent infection. Furthermore, these individuals have lower levels of in vitro cytokine production in response to infected macrophages. This suggests an underlying immune defect in individuals prone to disseminated TB infection. We have established cutting edge molecular techniques that allow us to 1) single-cell sort pathogen-reactive T cells 2) directly sequence their T cell receptor (TCR) alpha and beta chains 3) determine the T cell receptor alpha and beta chains of each T cell and 4) Reconstitute the alpha beta TCR complex in a reporter cell line to allow fine mapping of epitope specificity. As a proof of concept, in this application we will apply these techniques to an existing repository of peripheral blood mononuclear cells from individuals with latent tuberculosis (treated and untreated) and individuals with prior treated pulmonary or extrapulmonary TB. We hypothesize that the degree of TB-specific TCR diversity may be related to the degree of control an individual has over latent infection.