Western Blot Validation with Human Recombinant Protein<br> Loading: 50 ng per lane of human SARS-CoV-2 Spike S1 recombinant protein. Antibodies: SARS-CoV-2/SARS-CoV Spike 3221 (4 μg/mL), 1h incubation at RT in 5% NFDM/TBST. Secondary: Goat anti-rabbit IgG HRP conjugate at 1:10000 dilution.