PD-L1 (Extracellular Domain Specific) (D8T4X) Rabbit mAb

Programmed cell death 1 ligand 1 (PD-L1, B7-H1, CD274) is a member of the B7 family of cell surface ligands that regulate T cell activation and immune responses. The PD-L1 ligand binds the PD-1 transmembrane receptor and inhibits T cell activation. PD-L1 was discovered following a search for novel B7 protein homologs and was later shown to be expressed by antigen presenting cells, activated T cells, and tissues including placenta, heart, and lung (1-3). Similar in structure to related B7 family members, PD-L1 protein contains extracellular IgV and IgC domains and a short, cytoplasmic region. Research studies demonstrate that PD-L1 is expressed in several tumor types, including melanoma, ovary, colon, lung, breast, and renal cell carcinomas (4-6). Expression of PD-L1 in cancer is associated with tumor-infiltrating lymphocytes, which mediate PD-L1 expression through the release of interferon gamma (7). Additional research links PD-L1 expression to cancers associated with viral infections (8,9). 1.Dong, H. et al. (1999) Nat Med 5, 1365-9. 2.Freeman, G.J. et al. (2000) J Exp Med 192, 1027-34. 3.Liang, S.C. et al. (2003) Eur J Immunol 33, 2706-16. 4.Dong, H. et al. (2002) Nat Med 8, 793-800. 5.Thompson, R.H. et al. (2006) Cancer Res 66, 3381-5. 6.Pardoll, D.M. (2012) Nat Rev Cancer 12, 252-64. 7.Taube, J.M. et al. (2012) Sci Transl Med 4, 127ra37. 8.Lyford-Pike, S. et al. (2013) Cancer Res 73, 1733-41. 9.Chen, B.J. et al. (2013) Clin Cancer Res 19, 3462-73.