CD8+ T CELL RESPONSE IN RESISTANCE TO TUBERCULOSIS

结核病（TB）是一种慢性传染病， 胞内细菌病原体结核分枝杆菌。因此，细胞- 介导的免疫而不是抗体是关键的保护性免疫 针对M. TB.结核病动物模型研究表明， 主要组织相容性复合体（MHC）I类限制性CD 8 + T细胞 应答补充了由活化的巨噬细胞介导的宿主防御， CD 4 + T细胞，并在成功解决 分枝杆菌感染然而，在人类中，CD 8 + T细胞的作用具有以下特点： 没有得到充分解决。我们已经开发了一种体外试验， 基于一种新的计算机驱动的算法预测MHC I类配体 （肽）具有经证实的高准确性。我们的分析可以测量 通过适当的MHC I类等位基因呈递预测的肽， 允许鉴定由CD 8 + T细胞识别的表位。 因此，这些研究的总体目标是分析 CD 8 + T细胞应答在结核病抵抗中的作用。首先，分泌型分枝杆菌 具有已知序列的蛋白质将通过计算机程序进行分析， 潜在的CD 8 + T细胞表位的存在。列报该等 预测M. TB.通过MHC I类的-衍生肽将在 我们用抗原转运蛋白缺陷细胞系进行的肽结合试验 表达感兴趣的HLA等位基因。该分析将扩展到HLA 在结核病和艾滋病高发人群中占优势的等位基因 感染第二，这种方法将用于定量和 MHC I类限制性CD 8 + T细胞免疫的定性分析 回应M。TB. PPD+健康供体和TB中的-衍生肽 患者外周血中记忆性CD 8 + T细胞的频率 支气管肺泡灌洗液中活化的细胞毒性T淋巴细胞将 被衡量。结核病患者CD 8 + T细胞效应功能的比较 vs. PPD+健康供体，以及PPD+/HIV感染和活动性TB/HIV- 感染患者将确定CD 8 + T细胞之间的相关性， 对M. TB.感染这些患者。最后， M. TB. - 特异性CD 8 + T细胞克隆将被分离并在功能上被纯化。 表征了这些T细胞克隆将用于研究 对于M. TB.巨噬细胞抗原 在体外用活杆菌感染。

Tuberculosis (TB) is a chronic infectious disease caused by the intracellular bacterial pathogen Mycobacterium tuberculosis. Hence, cell- mediated immunity rather than antibodies is the critical protective immune response against M. tb. Studies with animal models of TB suggest that the major histocompatibility complex (MHC) class I-restricted CD8+ T-cell response complements host defenses mediated by activated macrophages and CD4+ T cells, and has an important role in successful resolution of mycobacterial infections. However, in humans the role of CD8+ T cells has not been fully addressed. We have developed an in vitro assay that is based on a novel computer-driven algorithm predicting MHC class I ligands (peptides) with a proven high accuracy. Our assay can measure the presentation of predicted peptides by proper MHC class I alleles, and thus allows for identification of the epitopes recognized by CD8+ T cells. Thus, the overall objective of these studies is the analysis of the role of CD8+ T-cell response in resistance to TB. First, secreted mycobacterial proteins with known sequences will be analyzed by the computer program for the presence of potential CD8+ T-cell epitopes. Presentation of these predicted M. tb. -derived peptides by MHC class I will be determined in our peptide-binding assay with an antigen transporter-deficient cell line expressing HLA alleles of interest. This analysis will be extended to HLA alleles predominant in populations with high incidences of TB and HIV infection. Second, this methodology will be used in quantitative and qualitative analysis of the MHC class I-restricted CD8+ T-cell immune responses to M. tb. -derived peptides in PPD+ healthy donors and TB patients. The frequencies of memory CD8+ T cells in the peripheral blood and activated cytotoxic T lymphocytes in the bronchio-alveolar lavage will be measured. Comparison of CD8+ T-cell effector functions in TB patients vs. PPD+ healthy donors, and also in PPD+/HIV-infected and active TB/HIV- infected patients will determine the correlation between the CD8+ T-cell responses and resistance to M. tb. infection in these patients. Finally, M. tb. -specific CD8+ T cell clones will be isolated and functionally characterized. These T cell clones will be used to study the requirements for MHC class I-restricted presentation of M. tb. antigens by macrophages infected in vitro with viable bacilli.