MCL1 and infection: To further confirm the up-regulation of Bak and Mcl-1 expression during IBV infection and to study if this up-regulation is cell type-specific, Vero, H1299 and Huh7 cells were infected with IBV at an M.O.I. of 1 and harvested at 0, 8, 12, 16 and 24 hours post-infection, respectively.