Cytotoxic T Lymphocyte Antigen 4

Cytotoxic T Lymphocyte Antigen 4 (CTLA-4) is a protein found on certain immune cells called T cells. It acts as a moderator, helping to prevent the immune system from becoming overactive and attacking the body's own tissues. When T cells are activated to fight infections or cancer, CTLA-4 helps turn down this response when it's no longer needed, maintaining balance and preventing excessive inflammation. Some cancer treatments use drugs to block CTLA-4, boosting the immune response to better attack tumors.