The coronavirus disease 2019 (COVID-19) pandemic has triggered a global health emergency and brought disaster to humans. Tremendous efforts have been made to control the pandemic, among which neutralizing antibodies (NAbs) are of specific interest to researchers. Neutralizing antibodies are generated within weeks after infection or immunization and can protect cells from virus intrusion and confer protective immunity to cells. Thus, production of NAbs is considered as a main goal for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccines and NAbs may be used for patient treatment in the form of monoclonal antibodies. Neutralization assays are capable of quantitatively detecting NAbs against SARS-CoV-2, allowing to explore the relationship between the level of NAbs and the severity of the disease, and may predict the possibility of re-infection in COVID-19 patients. They can also be used to test the effects of monoclonal antibodies, convalescent plasma and vaccines. At present, wild-type virus neutralization assay remains the gold standard for measuring Nabs, while pseudovirus neutralization assays, Surrogate virus neutralization test (sVNT) and high-throughput versions of neutralization assays are popular alternatives with their own advantages and disadvantages. In this review article, we summarize the characteristics and recent progress of SARS-CoV-2 neutralization assays. Special attention is given to the current limitations of various neutralization assays so as to promote new possible strategies with NAbs by which rapid SARS-CoV-2 serological diagnosis and antiviral screening in the future will be achieved.

中文翻译：

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SARS-CoV-2 中和试验的进展

2019 年冠状病毒病 (COVID-19) 大流行引发了全球卫生紧急情况，给人类带来了灾难。为控制大流行做出了巨大努力，其中中和抗体 (NAb) 是研究人员特别感兴趣的。中和抗体在感染或免疫后数周内产生，可以保护细胞免受病毒入侵并赋予细胞保护性免疫。因此，NAb 的生产被认为是严重急性呼吸系统综合症冠状病毒 2 (SARS-CoV-2) 疫苗的主要目标，NAb 可以以单克隆抗体的形式用于患者治疗。中和试验能够定量检测针对 SARS-CoV-2 的 NAb，从而可以探索 NAb 水平与疾病严重程度之间的关系，并可能预测 COVID-19 患者再次感染的可能性。它们还可用于测试单克隆抗体、恢复期血浆和疫苗的效果。目前，野生型病毒中和试验仍然是测量 Nabs 的金标准，而假病毒中和试验、替代病毒中和试验 (sVNT) 和中和试验的高通量版本是流行的替代方法，各有优缺点。在这篇综述文章中，我们总结了 SARS-CoV-2 中和试验的特点和最新进展。特别注意目前各种中和试验的局限性，以促进新的可能的 NAb 策略，从而在未来实现快速 SARS-CoV-2 血清学诊断和抗病毒筛查。