Detection of SARS-CoV-2 virus structural proteins as an aid to diagnosis and monitoring of COVID-19

最近的研究表明，新冠肺炎不仅是一种呼吸系统疾病，而且还可以影响多个器官，因为人体内都有这种致病病毒的受体。需要工具来研究致病病毒的存在及其对人类宿主各种生理和免疫系统的影响，以便能够更好地控制新冠肺炎。在这里，我们专注于开发高灵敏和准确的测试来检测和定量SARS-CoV-2病毒的主要结构蛋白和选定的人类蛋白，以允许测量宿主生物标记物的反应。我们方法的基础是稳定同位素标准和抗肽抗体捕获(SISCAPA)，这是一项提供指示疾病的生物标志物的灵敏测量的技术；在这种情况下，病毒蛋白本身和宿主蛋白随着病毒感染不同细胞和器官而发生变化。这项技术允许在全血、血浆、血清和唾液等复杂生物流体中进行廉价、多路生物标记物的测量。SISCAPA技术将允许直接测量SARS-CoV-2病毒蛋白，从而确定活动性感染，这是诊断传染病的金标准。目前使用标准聚合酶链式反应(PCR)的诊断测试只检测病毒的遗传物质，而不是组装的病毒本身。尽管聚合酶链式反应检测是进行人群筛查的极佳方法，但它们容易出现假阴性和假阳性结果，因此，单独一项衡量病毒结构成分的检测将补充聚合酶链式反应的诊断，使人们能够更好地了解疾病状态。由于SISCAPA技术使用酶消化的血液和唾液样本，干扰标准免疫分析的病毒特异性宿主抗体被销毁，从而能够准确检测病毒蛋白。除了对SARS-CoV-2病毒的检测外，对病毒感染反应产生的宿主蛋白的多重SISCAPA检测将提供有关感染过程的信息，从而为新冠肺炎的治疗和控制提供策略。

It has recently become clear that COVID-19 is not just a respiratory disease but also an illness that can affect multiple organs since there are receptors for the causative virus throughout the human body. There is a need for tools to study the presence of the causative virus and its effects on various physiological and immunological systems of the human host to enable better strategies for COVID-19 control. Herein we focus on development of highly sensitive and accurate tests for detecting and quantitating the main structural proteins of the SARS-CoV-2 virus and selected human proteins to allow measurement of host biomarker responses. The foundation of our approach is Stable Isotope Standards and Capture by Anti-Peptide Antibodies (SISCAPA), a technology that offers sensitive measurement of biomarkers indicative of disease; in this case the virus proteins themselves and host proteins that change in response to viral infection of different cells and organs. This technology allows inexpensive, multiplexed biomarker measurement in complex biological fluids such as whole blood, plasma, serum and saliva. SISCAPA technology will allow direct measurement of the SARS-CoV-2 virus proteins and thus determination of active infections, the gold standard for diagnosis of infectious diseases. Current diagnostic tests using the standard polymerase chain reaction (PCR) only detect genetic material from the virus, not the assembled viruses themselves. Although PCR tests are excellent for population screening, they are prone to false negative and false positive results, thus a separate test that measures structural components of the virus will complement diagnosis by PCR, allowing a better understanding of the disease state. Since SISCAPA technology uses enzyme-digested blood and saliva samples, virus-specific host antibodies that interfere with standard immunoassays are destroyed, allowing accurate detection of virus proteins. In addition to measurement of the SARS-CoV-2 virus, multiplexed SISCAPA measurement of host proteins produced in response to virus infection will yield information about the infection process, thus offering strategies for treatment and control of COVID-19.