Figure 6. ACE2 differentially expressed across cell lines in study of susceptibility to severe acute respiratory syndrome coronavirus 2 of cell lines and substrates used to diagnose and isolate influenza and other viruses. A) Mock transfected 293T cells or 293T cells transfected with plasmids expressing human, dog, cat, or mink ACE2 immunoblotted for ACE2 protein expression. B) Whole-cell lysate from uninoculated Vero E6, CV-1, A549, Mv1Lu, CRFK, MDCK-NBL-2, and MDCK-SIAT1 cell lines immunoblotted for endogenous ACE2 expression. Recombinant human ACE2 used as a positive control for detecting human ACE2. C) Relative ACE2 expression determined by real-time quantitative PCR. Data are mean of n = 6 +SD. Boxes are 1 SD away from the mean, and whiskers indicate the minimum and maximum. ACE, angiotensin-converting enzyme 2.