anti-PD-L1 (human), Rabbit Monoclonal (RM320)

Programmed death ligand 1 (PD-L1, B7-H1 or CD274) is a member of the growing B7 family of immune proteins that provide signals for both stimulating and inhibiting T cell activation. PD-L1 is a transmembrane protein involved in suppressing the immune system and rendering tumor cells resistant to CD8+ T cell-mediated lysis through binding of the Programmed Death-1 (PD-1) receptor. PD-L1 is widely expressed in several organs such as heart, skeletal muscle, placenta and lung, and in lower amounts in thymus, spleen, kidney and liver. Overexpression of PD-L1 may allow cancer cells to evade the actions of the host immune system. In renal cell carcinoma, upregulation of PD-L1 has been linked to increased tumor aggressiveness and risk of death, and, in ovarian cancer, higher expression of this protein has lead to significantly poorer prognosis. PD-L1 has also been linked to systemic lupus erythematosus and cutaneous melanoma. When considered in adjunct with CD8+ tumor-infiltrating lymphocyte density, expression levels of PD-L1 may be a useful predictor of multiple cancer types, including stage III non-small cell lung cancer, hormone receptor negative breast cancer and sentinel lymph node melanoma.