There is a constant war going on in your body. Working against you are viruses and cancer cells growing uncontrollably, threatening your tissues and organs. Fighting on your side are immune cells such as lymphocytes, a type of white blood cell that includes T cells and B cells. B cells produce antib odies that target viruses, while T cells coordinate immune responses and can kill infected or abnormal cells. Together, these defenses help limit infection and the spread of cancer. ...read more read less