Immunocheckpoint

Immunocheckpoints are proteins that regulate the immune system's response to infection and cancer. They are found on the surface of immune cells and play a crucial role in maintaining immune tolerance, preventing autoimmunity, and controlling inflammation. Immunocheckpoints are typically inhibitory, meaning they suppress the immune response, but there are also activating checkpoints that enhance immune activity.

The most well-known immunocheckpoints are programmed cell death protein 1 (PD-1) and its ligand PD-L1. PD-1 is expressed on activated T cells, while PD-L1 is found on antigen-presenting cells, such as dendritic cells and macrophages, as well as on tumor cells. The interaction between PD-1 and PD-L1 inhibits T cell activation and proliferation, allowing tumors to evade immune surveillance.

Immunocheckpoint inhibitors are a class of drugs that block these inhibitory signals, reactivating the immune system and enhancing its ability to recognize and eliminate cancer cells. These inhibitors have shown remarkable success in treating various types of cancer, including melanoma, lung cancer, and renal cell carcinoma. However, their use is not without risks, as they can also reactivate the immune system against normal tissues, leading to autoimmune side effects.

Other immunocheckpoints include cytotoxic T-lymphocyte-associated protein 4 (CTLA-4), T-cell immunoglobulin mucin-3 (TIM-3), and lymphocyte-activation gene 3 (LAG-3). Each of these checkpoints plays a unique role in modulating the immune response, and targeting them with specific inhibitors is an active area of research in cancer immunotherapy.