TNF and COVID-19: Due to the critical role of lung epithelium in COVID-19 disease progression [31], we established a lung airway epithelial cell model of SARS-CoV-2 ALI using Calu-3 cells and treatment with non-replicating SARS-CoV-2 receptor binding domain (RBD), added alone or in combination with a tri-cytokine mix containing TNFα, IL1β and IFNγ (RBD+CM).