Figure 2.

Concentration − response curves of trimeric SARS-CoV-2 spike variants, binding to hACE2 receptor protein. Schematic representation of non-competitive ELISA assay: plate coated with soluble hACE2 receptors and titrated with varying concentrations of biotinylated trimeric spike variants. The level of binding was quantified using streptavidin-HRP conjugate (A). The binding curves and EC₅₀’s of each spike variants was quantified using ELISA by titrating of biotinylated spike variants to soluble hACE2 coated on the plate and the amount of spike trimer binding were estimated using streptavidin-HRP conjugate (B) (Mean ± SEM, N = 2).