Although there was an increase in the MERS-CoV titer in IRF3 knocked down/out bat cells as compared to wildtype bat (Efk3) cells (Figure 5A,E), IRF3 knockout bat cells did not support MERS-CoV propagation to the same extent as MRC5 cells (Figure 5E) 48 h after infection. This evidence concerns the gene IRF3 and infection.