助力新冠疫苗研发| 我国科学家成功建立基于假病毒的SAR...

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随着冠状病毒在世界范围内迅速传播，目前新冠肺炎确诊病例已近80万。由此国内外已有60余家科研机构和疫苗企业参与新冠疫苗的研发。新型疫苗研发，如何评价其有效性至关重要。近日我国科学家在EMI杂志在线发表了题为“Establishment and validation of a pseudovirus neutralization assay for SARS-CoV-2”的研究论文。该研究可作为替代方法在生物安全二级实验室进行病毒中和试验，以此来评价疫苗的有效性，这将加速新冠疫苗研发进程，具有重要的理论和实际应用意义。



假病毒是一种多功能且安全的病毒学工具，特别是对于需要在生物安全三级及以上级别实验室操作的新发和再发的病毒，如SARS，HIV及埃博拉出血热等等。导致新冠肺炎的SARS-CoV-2病毒活毒操作目前需要在生物安全三级实验室进行。而新冠疫苗的有效性评价中一个重要环节是对临床血清效果的评价。该评价必须在生物安全3级实验室操作活病毒，这阻碍了疫苗和治疗剂的开发。
本文成功建立了一种基于假病毒的中和测定法，并优化了该检测方法的关键参数，包括细胞类型，细胞数量，病毒接种量。经验证，可有效检测针对SARS-CoV-2的中和抗体，并可在生物安全性二级实验室中进行操作。本文还对SARS-CoV-2恢复期的患者血清进行检测，结果显示血清具有高滴度的中和活性，这也佐证了恢复期血清疗法的可行性。



图2 SARS-CoV-2假病毒中和抗体测定



综上，本文成功建立了基于假病毒的SARS-CoV-2病毒中和测定方法，经初步验证可作为替代方法在生物安全二级实验室疫苗的有效性评价，易于推广使用，这将加速新冠疫苗研发进程，具有重要的理论和实际应用意义。中国食品药品检定研究院聂建辉博士、研究生李倩倩和吴佳静为本文共同第一作者，王佑春研究员、徐苗研究员和黄维金研究员为共同通讯作者。



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DOI：10.1080/22221751.2020.1743767
Abstract：Pseudoviruses are useful virological tools because of their safety and versatility, especially for emerging and re-emerging viruses. Due to its high pathogenicity and infectivity and the lack of effective vaccines and therapeutics, live SARS-CoV-2 has to be handled under biosafety level 3 conditions, which has hindered the development of vaccines and therapeutics. Based on a VSV pseudovirus production system, a pseudovirus-based neutralization assay has been developed for evaluating neutralizing antibodies against SARS-CoV-2 in biosafety level 2 facilities. The key parameters for this assay were optimized, including cell types, cell numbers, virus inoculum. When tested against the SARS-CoV-2 pseudovirus, SARS-CoV-2 convalescent patient sera showed high neutralizing potency, which underscore its potential as therapeutics. The limit of detection for this assay was determined as 22.1 and 43.2 for human and mouse serum samples respectively using a panel of 120 negative samples. The cutoff values were set as 30 and 50 for human and mouse serum samples, respectively. This assay showed relatively low coefficient of variations with 15.9% and 16.2% for the intra- and inter-assay analyses respectively. Taken together, we established a robust pseudovirus-based neutralization assay for SARS-CoV-2 and are glad to share pseudoviruses and related protocols with the developers of vaccines or therapeutics to fight against this lethal virus.

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