Fig. 2: Changes in viral NA content do not alter the ELLA results.
a Diagram of the PR8H1N1/BR18 and WSNH1N1/BR18 reassortant viruses. b Non-reduced Coomassie stained gel of purified PR8H1N1/BR18 and WSNH1N1/BR18 viruses (~5 µg). Oxidised (OX) N1-BR18 and H1-BR18 are indicated with the viral proteins NP and M1. Original gel image is provided in Supplementary Fig. 5. c NA activities (left panel) and HAU titres (right panel) are shown for three independently purified virus batches with protein concentrations of 1 mg/ml. P values from an unpaired student T test, 95% CI, are displayed. n.s.- not significant. d Binding of purified PR8H1N1/BR18 (left panel) and WSNH1N1/BR18 (right panel) virions to fetuin was measured by bio-layer interferometry. Curves were generated with equal densities of immobilised fetuin and the indicated purified virus protein concentrations. HA binding was measured in the presence of 10 µM zanamivir to inhibit NA activity and calculate the apparent dissociation constant (Kdapp) for fetuin based on total viral protein concentrations. To follow NA-mediated release, biosensors with bound viruses were transferred to a well without zanamivir. e ELLA virus titrations for the PR8H1N1/BR18 and WSNH1N1/BR18 viruses (left panel) are displayed with the ferret α-N1-BR18 antisera titration data (right panel) used to calculate the NAI titre. Virus titration data is from a single analysis run in duplicate. Antisera titration data is from two independent runs performed in duplicate. Source data for (c–e) are provided in the source data file.
