Figure 5.

Protein-based competition ELISA and authentic virus cell-based neutralization assay. (a) Assessment of the ability of the selected VHH-Fc antibodies to block the interaction between ACE2 and the RBD domain of SARS-CoV-2 strain Delta in a competitive ELISA setup. Values represented correspond to three independent experiments. (c) Fifty percent inhibitory concentration (IC₅₀) of the different VHH-Fc for the SARS-CoV2 variants Wuhan, Gamma and Delta by competitive ELISA was calculated. Data points represent mean values ± standard deviation of three independent experiments for each RBD from SARS-CoV2 variant. (b), (d) Neutralization of authentic SARS-CoV-2 virus (Wuhan strain) by the indicated VHH72-Fc constructs.

Alt Text: Protein-based competition ELISA and authentic virus cell-based neutralization assay. (a) Graph curves of the competitive ELISA data demonstrating better ability of engineered clones to antagonize RBD/ACE2 binding. Assessment of the ability of the selected VHH-Fc antibodies to block the interaction between ACE2 and the RBD domain of SARS-CoV-2 strain Delta in a competitive ELISA setup. Values represented correspond to three independent experiments. (b) Neutralization curves of authentic SARS-CoV-2 virus (Wuhan strain) by VHH72-Fc constructs. (c) Table describing the ELISA IC50 of all VHH-Fc construct (d) Table describing the neutralizing titers and the difference of VHH ability to neutralize the virus.