Fig. 3: NA escape mutations following passaging of PR8 virus in the presence of mAbs.

A Mean AUC reactivity of escape mutants with mutated viruses in ELISA, (N = 3). The mAbs used to select the mutants are indicated at the top of each panel, while the mAbs tested in ELISA are listed on the left. NA-mAb NA-1C1, was used to normalize virus amount on the plate and binding of each mAb to WT PR8 virus was set to 100%. B Mean of NA-inhibitory properties of the escape mutants in the presence of mAbs, (N = 3). mAbs were normalized to an irrelevant IgG mAb, anti-SARS-CoV-2 mAb#27, which was set to 0% inhibition. C Representative experiment of plaque reduction assays. Plaques formed by the escape mutants in the presence of mAbs, an irrelevant IgG mAb, anti-SARS-CoV-2 mAb#27, was used as a control (N = 3). D Location of amino acid replacements in true escape mutants mapped onto the homotetrameric NA (PDB: 6D96). Approximate binding sites of NPR-05 and NPR-07 mAbs are shown relative to the active site and substrate-binding site.