Programmed cell death 1

Programmed Cell Death Protein 1 (PD-1), also known as CD279, is a protein that in humans is encoded by the PDCD1 gene. PD-1 is a type of protein that plays a significant role in downregulating the immune system and promoting self-tolerance by suppressing T cell inflammatory activity. This mechanism is crucial for the prevention of autoimmune diseases, but it also has implications in cancer as it allows cancer cells to evade the immune system.

Function

PD-1 is a member of the immunoglobulin superfamily and is expressed on the surface of T cells as well as B cells, monocytes, and dendritic cells. The primary function of PD-1 is to prevent the immune system from attacking the body's own tissues. It does this by interacting with its ligands, PD-L1 and PD-L2, which are found on the surface of some tumor cells and other cells within the body. When PD-1 binds to its ligands, it sends an inhibitory signal to the T cell, reducing its ability to attack other cells, including cancer cells.

Clinical Significance

The interaction between PD-1 and its ligands has been a target for cancer immunotherapy. Drugs known as PD-1 or PD-L1 inhibitors can block this interaction, thereby allowing the immune system to attack cancer cells more effectively. These inhibitors have shown promise in treating a variety of cancers, including melanoma, non-small cell lung cancer, and kidney cancer.

PD-1 Inhibitors

Several PD-1 inhibitors have been approved for medical use, including nivolumab, pembrolizumab, and cemiplimab. These drugs have been a significant advancement in cancer treatment, offering hope for patients with previously untreatable forms of the disease.

Research

Research on PD-1 continues to evolve, with studies exploring its role in not only cancer but also autoimmune diseases, infections, and transplant rejection. Understanding the complex interactions of PD-1 in the immune system can lead to the development of new therapeutic strategies for a range of diseases.

See Also

• Immune checkpoint
• Cancer immunotherapy
• Autoimmune disease
• T cell