Optimization and Application of SARS-CoV-2 Pseudovirus Production System
HUANG Nan, LANG Qiaoli, LI Liping, YANG Xi*
The aim of this study was to establish an efficient and stable SARS-CoV-2 pseudovirus production system to evaluate the neutralizing ability of antibodies to SARS-CoV-2 in vitro. To produce high-titer pseudovirus, transfer plasmid types, the proportion of transfected plasmid and transfection methods were investigated in this study. The optimization results showed that the highest pseudovirus titer was obtained when 293T cells were transfected with the plasmids pCDH-CMV-MCS-EF1-copGFP, psPAX2 and pcDNA3.1-S at a mass radio of 0.300 μg׃0.225 μg׃0.240 μg using Lipofectamine™ 3000. Moreover, this optimized pseudovirus production system was also applicable to other SARS-CoV-2 variants, and three kinds of high-titer SARS-CoV-2 variants pseudoviruses were generated. Furthermore, pseudovirus neutralization assay was performed using the pseudovirus obtained in this study to test neutralizing activity of a reported antibody, and the IC50 value was 0.126 μg/mL. In summary, this study successfully established a simple and efficient method to generate high-titer SARS-CoV-2 pseudovirus, which could be used to evaluate the neutralizing activity of SARS-CoV-2 antibodies in vitro. This study provided a good foundation for the research of SARS-CoV-2 vaccines and drugs.
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