Natural Killer T (NKT) cells are a type of white blood cell that play an important role in the body's immune system. They are a type of lymphocyte, which are white blood cells that help the body fight off infections and other foreign invaders. NKT cells are unique in that they can recognize and respond to both foreign and self-antigens. They are also able to recognize and respond to certain types of cancer cells. NKT cells are important for helping the body fight off infections, cancer, and other diseases.