Robust neutralization assay based on SARS-CoV-2 S-bearing vesicular stomatitis virus (VSV) pseudovirus and ACE2-overexpressed BHK21 cells

Hualong Xiong; Yangtao Wu; Jiali Cao; Ren Yang; Jian Ma; Xiaoyang Qiao; Xiangyang Yao; Baohui Zhang; Yali Zhang; Wangheng Hou; Yang Shi; Jingjing Xu; Liang Zhang; Shaojuan Wang; Baorong Fu; Ting Yang; Shengxiang Ge; Jun Zhang; Quan Yuan; Baoying Huang; Zhiyong Li; Tianying Zhang; Ningshao Xia

To compare the infection efficiency of pseudotypes bearing different glycosylated protein, single cycle infectious recombinant VSVdG-EGFP-G was prepared and used to infect Vero-E6 cells transiently expressing full-length SARS-CoV-2-S protein and truncated SARS-CoV-2-Sdel18 protein that with C-terminal 18 aa truncation respectively, pseudotyped VSV-SARS-CoV-2-S and VSV-SARS-CoV-2-Sdel18 was obtained following the procedures described in methods ( Figure 1 ). Vero-E6, BHK21, BHK21-hACE2 and 293T cells were seeded to compare the infection efficiency of pseudotypes. The infection efficiency of VSV pseudotypes bearing truncated Sdel18 was much higher than that with full-length S protein. The results suggested that the combination of VSV-SARS-CoV-2-Sdel18 and BHK21-hACE2 cells could be a better alternation for establishing pseudotyped SARS-CoV-2 entry and neutralization assays.