(Biology A-level) What are the different types of T cell and what is their function?
T cells come in three major groups: T helper cells (TH), T killer cells (TC - for cytotoxic, a term meaning kills cells), and regulatory T cells (Treg).T helper cells play an important role in activating and coordinating the rest of the immune response. They release signalling molecules, generically termed as cytokines, to activate other immune cells as well as attract them to a site of infection. A large family of molecules that performs this role are the interleukins.T killer cells play an important role particularly against viruses. This is because T killer cells will attack and kill your body's own cells which are infected and already compromised. Some bacteria, in addition to all viruses, live and reproduce inside your own body's cells, and they are the target of T killer cells.The last T cell is the regulatory T cell. These have an important role in preventing the immune system from over-reacting to a pathogen or attacking your own body's cells unnecessarily. They also play a role in tolerance, and prevention of immune reactions to harmless stimuli such as food.
