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Immunoglobulin Variable (IgV) domain of Programmed death ligand 2 (PD-L2) The members here are composed of the immunoglobulin variable (IgV) domain of Programmed death ligand 2 (PD-L2; also known as B7-DC or CD273). Receptor-binding domain of PD-L2 is a cell-surface ligand that competes with PD-L1 for binding to the immunosuppressive receptor programmed death-1 (PD-1). PD-1 is a member of the CD28/B7 family that plays an important role in negatively regulating immune responses upon interaction with its two ligands, PD-L1 or PD-L2. PD-L2 has a higher affinity for PD-1 but is expressed at lower levels. PD-L2 interaction with PD-1 suppresses T cell proliferation, cytokine production and cytotoxic activity. PD-L2 is expressed on tumor cells, antigen-presenting cells or APCs (such as macrophages, B cells and dendritic cells), and a variety of other immune and nonimmune cells. Tumor expression of PD-L2 may contribute to tumor evasion of immune destruction by inactivating T cells. Thus, PD-L2 is a negative predictor for prognosis among solid cancer patients. |
Jiyao W et al.(2023). "The conserved domain database in 2023.",