CD274

CD274, also known as PD-L1, is a 40 kDa type I transmembrane protein that belongs to the B7 family of the Ig superfamily. PD-L1 binds to its receptor, PD-1, found on CD4 and CD8 thymocytes as well as activated T and B lymphocytes and myeloid cells. Engagement of PD-L1 with PD-1 leads to inhibition of TCR-mediated T cell proliferation and cytokine production (IL-10, IFN-γ). PD-L1 is thought to play an important role in tumor immune evasion. Induced PD-L1 expression is common in many tumors and results in increased resistance of tumor cells to CD8 T cell mediated lysis. The 29E.2A3 antibody has been shown to block the binding of PD-1-Ig to PD-L1.