Brothers in Arms (IMAGE) University of Pennsylvania School of Medicine Caption This is an inflamed mouse lung. Infiltrating innate immune cells are stained in red and green. Credit Meera Nair, PhD, Michael Abt, PhD, David Artis, PhD; Perelman School of Medicine, UPenn Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.