TB Diagnosis Based on Promiscuous PE-PGRS Epitopes

描述（由申请人提供）：迫切需要一种简单、敏感和特异的即时检测方法，可以诊断HIV-和HIV+受试者的结核病，以抗击肆虐的结核病流行。在M.结核分枝杆菌（复合型）中存在PE-PGRS基因，但包括M. avium（其折磨5-7%的HIV+受试者）和M.麻风病人这使得PE-PGRS蛋白成为纳入TB诊断测试的有吸引力的靶标。我们的初步研究表明，由几种PE-PGRS蛋白共享的免疫显性表位（混杂表位）在TB患者中具有高度免疫原性。基于这些结果，我们提出鉴定肺结核兔肺中高表达的PE-PGRS基因，这些肺结核兔被临床分离的肺炎支原体气溶胶感染。结核病，并绘制其免疫显性混杂表位特异性识别的抗体从HIV-TB+和HIV+TB+患者。这些表位可以作为结核病简单肽基诊断试验的基础。具体而言，我们提出：a）鉴定由M高度表达的PE-PGRS基因子集。结核病在肺中的生长和复制过程中，并表征蛋白质（目标#1）; B）解剖在目的#1中选择的PEPGRS蛋白以描绘被来自HIV-TB+和HIV+TB+患者的血清抗体识别但不被PPD-识别的免疫显性表位，PPD+和/或BCG接种的健康受试者或HIV+TB-对照（目标#2）和c）评估目标#2与来自TB的不同阶段的个体患者的血清进行比较，以鉴定肽的最佳集合，并评估与来自不同地理环境的患者的血清的反应性的最佳肽子集（目标#3）。公共卫生相关性：拟议的工作可能会导致开发一种廉价，可靠和快速的结核病诊断测试。到目前为止，还没有可靠的结核病快速检测方法，这将是该领域的一个重大进步。

DESCRIPTION (provided by applicant): A simple sensitive and specific point-of-care test that can diagnose TB in both HIV- and HIV+ subjects is urgently needed for combating the raging TB epidemic. A subfamily of genes, called PE-PGRS genes is present in M. tuberculosis (complex), but there are no PE-PGRS genes in several other common mycobacterial pathogens including M. avium (which afflicts 5-7% of the HIV+ subjects) and M. leprae. This makes the PE-PGRS proteins attractive targets for inclusion into diagnostic tests for TB. Our preliminary studies demonstrate that immunodominant epitopes that are shared by several PE-PGRS proteins (promiscuous epitopes) are highly immunogenic in TB patients. Based on these results we propose to identify the PE-PGRS genes that are highly expressed in the lungs of tuberculous rabbits infected with aerosols of clinical isolates of M. tuberculosis, and map their immunodominant promiscuous epitopes recognized specifically by antibodies from HIV-TB+ and HIV+TB+ patients. These epitopes can be the basis of a simple peptide-based diagnostic test for TB. Specifically, we propose to: a) Identify the subset of PE-PGRS genes that is highly expressed by M. tuberculosis during growth and replication in lungs, and characterize the proteins (Aim #1); b) Dissect the PEPGRS proteins selected in Aim # 1 to delineate the immunodominant epitopes that are recognized by serum antibodies from HIV-TB+ and HIV+TB+ patients but not by PPD-, PPD+ and/or BCG vaccinated healthy subjects or HIV+TB- controls (Aim #2) and c) Evaluate the reactivity of epitopes identified in Aim #2 with sera from individual patients at different stages of TB to identify the optimal set of peptides and evaluate the optimal peptide-subset for reactivity with sera from patients from different geographical settings (Aim # 3). PUBLIC HEALTH RELEVANCE: The work proposed could lead to development of a cheap, reliable and rapid diagnostic test for TB. No reliable rapid tests for TB exist so far and this would be a major advancement in the field.