We assessed the expression of hACE2 in macrophages derived from hACE2 mice and compared response to infection with SARS-CoV-2 with wild-type (C57BL/6) control mice and the widely used K18-hACE2 [B6.Cg-Tg(K18-ACE2)2Prlmn/J] mouse, which is a transgenic mouse overexpressing hACE2 under control of the keratin18 (K18) promoter and is susceptible to infection by both SARS-CoV-1 and SARS-CoV-2 (58, 59). The gene discussed is ACE2; the disease is infection.