TCR (T cell receptor)

A T cell receptor (TCR) is a molecule on the surface of T cells, a type of immune cell. It acts like a sensor that recognizes specific parts of foreign substances, such as viruses or bacteria, called antigens. When the TCR detects its target, it activates the T cell to mount an immune response, helping the body fight infections or abnormal cells. Each T cell has a unique TCR, allowing the immune system to identify a wide variety of threats effectively. TCRs are essential for coordinating the immune system’s ability to distinguish between the body's own cells and harmful invaders.