Patrolling the Border (IMAGE) Rockefeller University Caption New research explains the development of intraepithelial lymphocytes, immune cells in the thin lining of the intestine. Above, transverse sections of fingerlike villi that project into the intestine show green IELs within blue epithelial cells. Credit Bernardo Reis 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.