Non-transfected (–) and transfected (+) 293T whole cell extracts (30 μg) were separated by 15% SDS-PAGE, and the membrane was blotted with SARS-CoV-2 (COVID-19) ORF9b antibody (GTX136053) diluted at 1:5000. The HRP-conjugated anti-rabbit IgG antibody (GTX213110-01) was used to detect the primary antibody.