Programmed cell death 1 ligand 1 (PD-L1), also known as B7-H1 or CD274, is a B7 family protein that is involved in regulation and attenuation of the adaptive immune response and peripheral T cell tolerance.1,2,3,4 It is a 290-amino acid type I transmembrane protein encoded by the CD274 gene in humans and is comprised of a 239-amino acid extracellular domain consisting of a signal peptide, an IgV-like domain, and an IgC-like domain, a transmembrane domain, and a cytoplasmic tail.1,5 PD-L1 is constitutively expressed in T and B cells, dendritic cells, macrophages, and regulatory T cells (Tregs), as well as a variety of nonhematopoietic cells and is upregulated by IFN-γ.3 Binding of PD-L1 to its receptor, programmed cell death protein 1 (PD-1), suppresses T cell proliferation, migration, and cytokine production.2,4 PD-L1 is also aberrantly expressed in a variety of tumor cells, and expression of PD-L1 in tumor tissue is associated with poor prognosis in patients with renal cell carcinoma. 6,7,8 Formulations containing PD-L1 blocking antibodies have been used in the treatment of a variety of cancers. Cayman's PD-L1 Extracellular Domain (human, recombinant) protein can be used for ELISA, binding assay, and cell-based assay applications. This protein is a disulfide-linked homodimer. The reduced monomer, comprised of PD-L1 (amino acids 19-239) fused to mouse IgG1 Fc at its C-terminus, consists of 455 amino acids, has a calculated molecular weight of 51.7 kDa, and a predicted N-terminus of Phe19 after signal peptide cleavage. As a result of glycosylation, the monomer migrates at approximately 66 kDa by SDS-PAGE under reducing conditions.WARNING This product is not for human or veterinary use.
