ACE2 and infection: The authors performed four different types of infections: (i) unmodified A549 cells were infected with SARS-CoV-2, or (ii) A549 cells overexpressing the ACE2 receptor with Low Multiplicity of infection (Lo MOI) or (iii) cells expressing ACE2 with high MOI, or (iv) cells expressing ACE2 Hi MOI treated with interferon signaling inhibitor Ruxolitinib (Ruxo).