ACE2 and infection: To investigate whether SARS-CoV-2 could induce MC degranulation in vivo, the ACE2-humanized inbred mice,46 termed C57BL/6N-Ace2em2(hACE2-WPRE,pgk-puro)/CCLA, were intranasally infected with SARS-CoV-2 (strain 107) at a dose of 2 × 106 TCID50 (50% tissue culture infective dose), then euthanized at the different days post-infection (dpi) to harvest lung tissues for histological analysis.