Figure 3. Influenza virus substrates not infected by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in study of susceptibility to SARS-CoV-2 of cell lines and substrates used to diagnose and isolate influenza and other viruses. A) Vero E6, MDCK-NBL-2, MDCK-Atlanta, MDCK-London, MDCK-SIAT1, MDCK-hCK, and chicken embryo fibroblast cells inoculated with USA-WA1 at 5 × 104 TCID50/well in 12-well plates (MOI 0.1 to ≈0.3, depending on cell line). B) USA-WA1 total viral RNA levels in allantoic fluid from infected eggs quantified by real-time reverse transcription PCR using a standard curve generated by synthetic RNA. Four eggs with undetectable RNA not plotted for E3. Data are mean of n = 3 +SD (cells) or n = 24 +SD (eggs). TCID50, median tissue culture infectious dose.