Biolegend, 799506, Biotinylated Recombinant Human PD-1-Fc (CD279) Chimera (carrier-free)

Programmed death-1 (PD-1) is a type I transmembrane protein initially isolated from apoptosis-induced cells by subtractive hybridization. The amino acid sequence of mouse PD-1 shares 59.4% identity to the human counterpart, and a putative tyrosine kinase-association motif is well-conserved. Its extracellular region consists of a single Ig-like variable (IgV) domain. PD-1 is an inhibitory molecule expressed by activated B and T cells and has been implicated in immune tolerance. PD-L1 and PD-L2 are the ligands for PD-1 and their binding leads to the inhibition of T cell receptor-mediated lymphocyte proliferation and cytokine secretion. PD-1/PD-L1 interaction suppresses immune responses against autoantigens and tumors, and plays an important role in the maintenance of peripheral immune tolerance. Interaction between PD-1 and PD-L1 promote tolerance by blocking TCR-mediated signaling.  PD-L1 expression by tumor cells allow tumor progression by suppressing antitumor T-cell responses. Antibodies against PD-1 or PD-L1 lead to increased antitumor immunity.