Now, what about development of our immune system? Well, remember, T cells, also known as T lymphocytes, mature and develop inside the thiamis. So what happens inside the thiamis, which is an organ found in this section of the body inside the thiamis, those T lymphocytes are tested against self antigens. Remember, self antigens are proteins found on the healthy cells of our body. And if those T lymphocytes bind onto these healthy self antigens, then the binding process will initiate apatosis and those T cells will be killed off. The reason is if the T cells actually bind onto cell antigens, that means those T lymphocytes will begin to kill off the healthy cells of our body.