IL-4 and TGF-β Regulate Inflammatory cytokines and Cellular Infiltration in the Lung in Mouse-adapted SARS-CoV-2 Infection.

Summary: When people get really sick with COVID-19, it's often because their immune system overreacts, causing severe swelling in the lungs long after the virus is gone. Scientists wanted to know how the body normally stops this from happening. They studied mice with a mild form of COVID-19 and blocked certain calming signals in their immune systems. They found that two specific signals, called TGF-β and IL-4, are super important. Without TGF-β, the mice had more dangerous swelling cells in their lungs and blood. Without IL-4, the mice lost more weight and had more swelling around their blood vessels. This shows that these two signals act like natural brakes to keep the immune system from causing too much damage during a COVID-19 infection.