CD279

CD279, also known as Programmed Death-1 (PD-1), is a protein that in humans is encoded by the PDCD1 gene. PD-1 is a type of immune checkpoint and plays a vital role in downregulating the immune system and promoting self-tolerance by suppressing T cell inflammatory activity. This mechanism prevents autoimmune diseases but can also be exploited by cancer cells to evade the immune system.

Function

CD279/PD-1 is a member of the immunoglobulin superfamily and is expressed on the surface of activated T cells, B cells, and macrophages. The interaction of PD-1 with its ligands, PD-L1 and PD-L2, which are expressed on the surface of some tumor cells and antigen-presenting cells, leads to the inhibition of T-cell activation and cytokine production. This interaction is crucial for the maintenance of peripheral tolerance and the prevention of autoimmune responses. However, in the context of cancer, it can lead to the suppression of anti-tumor immunity.

Clinical Significance

The inhibitory role of PD-1 in immune responses has made it a target for cancer immunotherapy. Blocking the interaction between PD-1 and its ligands with monoclonal antibodies can enhance T-cell responses in vitro and mediate preclinical antitumor activity. This has led to the development of several PD-1 inhibitors, such as nivolumab and pembrolizumab, which have been approved for the treatment of various types of cancer, including melanoma, non-small cell lung cancer, and renal cell carcinoma.

In addition to cancer, the PD-1 pathway is also being investigated in the context of chronic infections and autoimmune diseases, where modulation of PD-1-mediated signaling may offer therapeutic benefits.

Genetics

The PDCD1 gene is located on chromosome 2 in humans. Variants of this gene have been associated with susceptibility to autoimmune diseases such as systemic lupus erythematosus (SLE) and rheumatoid arthritis, highlighting the importance of PD-1 in immune regulation.

See Also

• Immune checkpoint
• Immunotherapy
• T cell
• Autoimmune disease