Novel serological biomarker for rapid tuberculosis diagnosis

描述（由申请人提供）：识别易于检测的结核病生物标志物是全球卫生优先事项。2010年估计有880万活动性结核病新发病例，结核病仍然是一个全球公共卫生问题。快速诊断结核病对于早期开始治疗和减少传播、发病率和死亡率至关重要。目前的快速诊断检测要么缺乏敏感性（如痰液镜检），要么不容易应用于资源有限的环境（如核酸检测），而绝大多数结核病例都发生在这些环境中。血清抗体（Abs）可以快速检测的方法，可以变成简单的试纸格式。然而，结核病血清学几十年来一直在努力开发准确的结核病检测方法，但没有成功。我们最近证明，致病性分枝杆菌产生膜囊泡（MVs），有助于分枝杆菌毒力小鼠。这些囊泡提供了释放免疫调节因子的有效途径，宿主对病毒的免疫反应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MVs中富集的3个蛋白诱导了结核病高度敏感和特异性的Ab生物标志物。因此，我们的首要假设是，同时Ab对特定MV蛋白的反应与TB强烈且显著相关。因此，我们建议使用我们的特征良好的血清样本收集来开发这些生物标志物，用于适用于资源有限环境的快速护理点（POC）测试。我们的具体目的是：1)观察疑似结核患者对分枝杆菌MVs的抗体反应；2)鉴定引发TB Ab生物标志物标记的分枝杆菌MV蛋白，在体外表达，并验证Ab反应，用于诊断检测的开发。这是一个高度可行的项目，具有可靠的初步数据和一种创新方法，可满足对简单、快速结核病诊断的需求。本建议的最终目标是开发一种测定方法，使POC试验有可能取代痰液显微镜诊断结核病。

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.