PD-L2

Programmed death-1 (PD-1) is expressed on activated T cells and B cells and binds to two ligands, programmed death ligand 1 (PD-L1) and programmed death ligand 2 (PD-L2). Expression of PD-L2 was originally thought to be exclusive to dendritic cells and activated macrophages; however recent evidence shows that PD-L2 is up-regulated in human tumors and may be linked to poor outcome. The pattern of PD-L1 and PD-L2 expression is very distinct.