ACE2 and COVID-19: To better understand immune dysregulation and immunopathogenesis in COVID-19, we established an in vitro coculture system in which Caco-2-ACE2-N IECs were exposed to SARS-CoV-2 GFP/ΔN-trVLP for 48h; supernatants were replaced with fresh medium suitable for PBMCs; the infected IECs were then cocultured for 16h with human peripheral blood mononuclear cells (PBMCs) in Transwells.