Fig. 5.

Neutralization potency of ACE2-IgG4-Fc fusion proteins increases with evolution of pandemic SARS-CoV-2 variants. Serial dilutions of ACE2-IgG4-Fc fusion constructs 1 and 3 were pre-incubated with the indicated SARS-CoV-2 primary isolates or VoCs and tested for their ability to prevent cytotoxicity following infection of A549-hACE2 cells. Neutralization of SARS-CoV-2-Jan, SARS-CoV-2-April and SARS-CoV-2 VoCs alpha, beta and delta by enzymatically active ACE2-IgG4-Fc construct 1 (left) and enzymatically inactive ACE2-IgG4-Fc construct 3 (right). Data given are means ± SEM of three independent experiments each. 50% inhibitory concentrations (IC50 values) determined as well as the 95% confidence interval (CI 95%) are shown for each construct. The dashed lines indicate the IC50 values on the corresponding curves.