TNF and infection: In the SARS-CoV-2 MA10 model, surviving older mice cleared infection by 15 dpi but exhibited damaged pulmonary epithelia accompanied by secretion of a spectrum of pro-inflammatory and pro-fibrotic cytokines often up-regulated in fibrotic disease in humans, including IL-1β, TNF-α, GM-CSF, TGF-β, IL-33, and IL-17A (76).