Zoomed-in section of human thymus (IMAGE) The Francis Crick Institute Caption Zoomed-in section of a human thymus after birth, showing thymocytes (red), epithelial cells (cyan), and Polykeratin stem cells next to fibronectin areas (green). Credit Roberta Ragazzini, the Francis Crick Institute, Developmental Cell. Usage Restrictions Only use with this press release and with credit License Original 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.