T Cell (IMAGE) University of California - San Diego Caption Colorized scanning electron micrograph of a T cell, a type of lymphocyte that plays a central role in the immune response. Credit NIAID Usage Restrictions Use photo credit 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.