Figure 3.

Analysis of antigenicity of SARS-CoV-2 variants using a panel of engineered ACE2 and neutralizing monoclonal antibodies. (a) The inhibition effect of WT-sACE2 (black) and C4-1 (pink) in SARS-CoV-2 variants entrance into ACE2 expressing HEK-293T cell lines. (b) The inhibition effect of monoclonal antibodies. Dashed lines indicate the neutralizing range of C4-1. Therapeutic effects for cocktails of C4-1 and monoclonal antibodies against beta (c), gamma (d), delta (e), and omicron (f) variants. Unpaired t-test was used to analyse differences between groups. *p<0.05, ** $p<0.01$, ***p<0.001, ****p<0.0001. EC ${}_{50}$ was calculated based on all dilutions of soluble ACE2 protein. The limit of EC ${}_{50}$ detection was 0–12000 ng/mL for panel A and 0–10000 ng/mL for panel b, c, d, e, and f. All results were obtained from three independent experiments. In each experiment, the infection assay was performed in duplicate wells. Data are mean ±SEM, n = 2 replicates.