SERPINA1 and infection: We therefore applied PMP to SARS-CoV-2 infected A549-ACE2-TMPRSS2 (AAT) cells, which are highly permissive to SARS-CoV-2 (Rihn et al., 2021) and infection at a high multiplicity of infection (MOI) results in over 90% infection by 24 hr (Figure 1A).