Like an office building using a surveillance system and a man to identify and prevent unwanted visitors from entering the premises, the immune system uses an army of specialized cells and organs to identify, and prevent foreign invaders from debilitating our bodies. An indispensable part of the body’s defense system includes B and T cells which are special units of the immune system. They play a crucial role 24/7 in searching and destroying the relentless onslaught of harmful viruses, bacteria, cancer cells and toxins.