Petrie Image (IMAGE) Scripps Research Institute Caption The team found that stromal cells (green) in the thymus were deficient in an antioxidant enzyme called catalase (red), resulting in accelerated metabolic damage. Credit Photo courtesy of The Scripps Research Institute. 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.