Cytotoxic T-lymphocyte-associated protein 4

Cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) is a molecule found on certain immune cells called T-cells. It functions as a natural "brake" to control the immune response, preventing it from becoming overactive and damaging the body's own tissues. When T-cells are activated to fight infections or cancer, CTLA-4 helps turn off the response once the threat is managed. Some cancer treatments use drugs called immune checkpoint inhibitors to block CTLA-4, boosting the immune system's ability to attack tumors. Essentially, CTLA-4 balances immune activity to prevent harm while still defending against threats.