Immune Checkpoint Protein (IMAGE) Tokyo University of Science Caption Scientists find out how an immune checkpoint protein called PD-L2, which is expressed on the surface of a type of immune cells, is regulated at the molecular level. Credit Tokyo University of Science 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.