Description
Plays a critical role in induction and maintenance of immune tolerance to self. As a ligand for the inhibitory receptor PDCD1, modulates the activation threshold of T-cells and limits T-cell effector response (PubMed:11238124). The PDCD1-mediated inhibitory pathway is exploited by tumors to attenuate anti-tumor immunity and facilitate tumor survival (By similarity). May costimulate helper T-cell subsets through a yet unknown activating receptor (PubMed:11015443, PubMed:12719480)