Novel serological biomarker for rapid tuberculosis diagnosis

描述（由申请人提供）：鉴定易于检测的结核病生物标志物是全球卫生优先事项。据估计，2010年发生了880万例新的活动性结核病病例，结核病仍然是一个全球公共卫生问题。结核病的快速诊断对于早期开始治疗和减少传播、发病率和死亡率至关重要。目前的快速诊断测试缺乏灵敏度（例如痰液显微镜检查）或不能容易地应用于绝大多数TB病例发生的资源有限的环境（例如核酸检测）。血清抗体（Abs）可通过可转化为简单试纸形式的方法快速检测。然而，数十年来，结核血清学一直未能成功地开发出结核病的准确检测方法。我们最近已经证明，致病性分枝杆菌产生膜囊泡（MV），有助于分枝杆菌在小鼠中的毒力。这些囊泡提供了释放免疫调节因子的有效途径，并且宿主对MV的免疫应答为鉴定新的生物标志物提供了独特的机会。我们的初步数据表明，在致病性分枝杆菌的MV中富集的3种蛋白质诱导了针对TB的高度敏感和特异性的Ab生物标志物签名。因此，我们的总体假设是，对特定MV蛋白的同时Ab应答与TB强烈且显著相关。因此，我们建议使用我们的良好表征的血清样本收集来开发这些生物标志物，用于在资源有限的环境中适用的快速床旁（POC）测试。我们的具体目标是：1）表征疑似患有TB的患者中对分枝杆菌MV的Ab应答;和2）鉴定引发TB Ab生物标志物特征的分枝杆菌MV蛋白，在体外表达它们，并验证用于诊断测定开发的Ab应答。这是一个高度可行的项目，具有可靠的初步数据和创新方法，可满足对简单、快速结核病诊断的需求。该提案的最终目标是开发一种检测方法，该方法可能导致POC检测，并有可能取代痰液显微镜检查用于结核病的诊断。

DESCRIPTION (provided by applicant): Identification of easily detectable biomarkers for TB is a global health priority. With an estimated 8.8 million new cases of active tuberculosis (TB) occurring in 2010 TB remains a global public health problem. Rapid TB diagnosis is critical for early treatment initiation and reduction of transmission, morbidity, and mortality. Current rapid diagnostic tests lack either sensitivity (e.g. sputum microscopy) or cannot be easily applied in resource- limited settings (e.g. nucleic acid detection) where the vast majority of TB cases occur. Serum antibodies (Abs) can be rapidly detected by methods that can be turned into simple dip-stick formats. TB serology, however, has suffered from decades of unsuccessful attempts to develop accurate tests for TB. We have recently demonstrated that pathogenic mycobacteria produce membrane vesicles (MVs) that contribute to mycobacterial virulence in mice. These vesicles provide an effective way to release immune-modulatory factors and the host immune responses to MVs provide a unique opportunity for identification of novel biomarkers. Our preliminary data indicate that 3 proteins enriched in MVs of pathogenic mycobacteria induce a highly sensitive and specific Ab biomarker signature for TB. Therefore, our overarching hypothesis is that the simultaneous Ab response to specific MV proteins is strongly and significantly associated with TB. Consequently, we propose to use our well-characterized serum sample collection to develop these biomarkers for use in a rapid point-of-care (POC) test applicable in resource-limited settings. Our specific aims are: 1) To characterize Ab responses to mycobacterial MVs in patients suspected of having TB; and 2) To identify the mycobacterial MV proteins that elicit a TB Ab biomarker signature, express them in vitro, and verify Ab responses for diagnostic assay development. This is a highly feasible project with robust preliminary data and an innovative approach to address the need for a simple, rapid TB diagnostic. The ultimate goal of this proposal is the development of an assay that could lead to a POC test with the potential of replacing sputum microscopy for the diagnosis of TB.