Consistent with the data from our binding and SARS-CoV-2 pseudoparticle experiments, A549 cells expressing humanized koala (T31K) or mouse (H353K) ACE2 were readily susceptible to SARS-CoV-2 infection; as expected, the F83Y mutation in koala (T31K) or mouse (H353K) ACE2 further enhanced infection efficiency. The gene discussed is ACE2; the disease is infection.