ACE2 and viral infectious disease: The neutralizing potential of these antibodies to inhibit viral infection and cytopathic effect, was first tested in vitro in HEK293 cells overexpressing ACE2 and TMRPSS2 (HEK-ACE2-TMPRSS2), utilizing the ancestral (A.2.2) SARS-CoV-2 strain, and also Beta and Delta variants.