The global pandemic of coronavirus disease 2019 (COVID-19) is a disaster for human society. A convenient and reliable neutralization assay is very important for the development of vaccines and novel drugs. In this study, a G protein-deficient vesicular stomatitis virus (VSVdG) bearing a truncated spike protein (S with C-terminal 18 amino acid truncation) was compared to that bearing the full-length spike protein of SARS-CoV-2 and showed much higher efficiency. A neutralization assay was established based on VSV-SARS-CoV-2-Sdel18 pseudovirus and hACE2-overexpressing BHK21 cells (BHK21-hACE2 cells). The experimental results can be obtained by automatically counting the number of EGFP-positive cells at 12 h after infection, making the assay convenient and high-throughput. The serum neutralizing titer measured by the VSV-SARS-CoV-2-Sdel18 pseudovirus assay has a good correlation with that measured by the wild type SARS-CoV-2 assay. Seven neutralizing monoclonal antibodies targeting the receptor binding domain (RBD) of the SARS-CoV-2 S protein were obtained. This efficient and reliable pseudovirus assay model could facilitate the development of new drugs and vaccines.

2019年冠状病毒病（COVID-19）在全球大流行，对人类社会来说是一场灾难。方便可靠的中和测定对于疫苗和新药的开发非常重要。在这项研究中，将带有截短刺突蛋白（C 端 18 个氨基酸截断的 S）的 G 蛋白缺陷型水泡性口炎病毒 (VSVdG) 与带有 SARS-CoV-2 全长刺突蛋白的病毒进行了比较，结果显示效率更高。基于 VSV-SARS-CoV-2-Sdel18 假病毒和 hACE2 过表达 BHK21 细胞（BHK21-hACE2 细胞）建立了中和测定法。感染后12小时自动计数EGFP阳性细胞数即可获得实验结果，实验方便且高通量。 VSV-SARS-CoV-2-Sdel18假病毒测定法测得的血清中和滴度与野生型SARS-CoV-2测定法测得的血清中和滴度具有良好的相关性。获得了七种针对 SARS-CoV-2 S 蛋白受体结合域 (RBD) 的中和单克隆抗体。这种高效可靠的假病毒检测模型可以促进新药和疫苗的开发。