Programmed cell death protein 1 receptor and Programmed death-ligand 1 (PD-1 receptor (for Programmed cell death protein 1), PD-L1 (for Programmed death-ligand 1))

Programmed cell death protein 1 receptor (PD-1) and its principal ligand, Programmed death-ligand 1 (PD-L1), comprise a key immune checkpoint pathway that modulates T cell activity and peripheral tolerance[1][3][5][7]. PD-1 is a type I transmembrane protein primarily expressed on activated T cells, B cells, and myeloid cells[3][7]. It is a member of the immunoglobulin superfamily, related to other immune regulatory proteins such as CTLA-4 and CD28[3][9]. PD-L1, also a type I transmembrane glycoprotein, belongs to the B7 protein family and is widely expressed on tumor cells, antigen-presenting cells, and various tissues[1][2][7]. The binding of PD-1 to PD-L1 induces a phosphorylation cascade via its cytoplasmic ITIM and ITSM motifs, recruiting SHP-2 phosphatase to inhibit PI3K/Akt and Ras-ERK pathways, resulting in suppressed cytokine production, cell cycle arrest, and reduced cytolytic activity[1][7]. This negative regulation creates a major mechanism by which tumors evade immune detection[1]. Blockade of the PD-1/PD-L1 interaction with therapeutic antibodies releases the inhibition on T cells, enabling restoration of anti-tumor immunity—a strategy now central to cancer immunotherapy[5][8]. PD-1/PD-L1 inhibitors are approved for numerous cancers, including melanoma, non-small cell lung cancer, renal cell carcinoma, and others, with ongoing studies expanding their indications. The expression levels of PD-L1 in tumors are frequently used as a biomarker to select patients for checkpoint blockade therapy[7]. The pathway is also involved in preventing autoimmunity, and its therapeutic modulation is associated with immune-related side effects, particularly inflammatory responses in various organs[7]. Variants in PD-1/PD-L1 genes are associated with susceptibility to autoimmune diseases[5]. There is no significant misspelling or error in your target name; this is one of the most prominent drug targets in modern immunotherapy and cancer medicine[1][3][7].

Other names

PD-1 (Programmed cell death protein 1)PDCD1 (Gene symbol for PD-1)CD279 (Cluster of differentiation designation for PD-1)Programmed death-ligand 1 (PD-L1)CD274 (Cluster of differentiation designation for PD-L1)B7-H1 (another name for PD-L1)

Competitive inhibition (monoclonal antibodies block PD-1/PD-L1 interaction); Immune checkpoint blockade restores T cell activity by preventing negative regulation; Enhancement of anti-tumor immunity; Restoration of cytokine release, cytolytic activity, and T/B cell function.