What is Immunotherapy?

To begin to understand immunotherapy, one has to have a basic knowledge of the immune system itself. When functioning properly, the immune system identifies and attacks a variety of threats, including viruses, bacteria, parasites and to some degree cancer, while distinguishing these foreign substances from the bodies’ own healthy tissue. The immune system includes several organs that make a variety of different types of white blood cells and a complex communications system to coordinate them. For example, certain cells in the immune system constantly check every cell and tissue in the body to look for invaders that don’t belong. When an invader is detected, these cells release a series of substance that raise the alarm for the immune system’s soldiers, white blood cells called the B and T-cells. These cells then identify specifically who the invader is and the T-Cells tell the body to produce many more cells trained to find and kill the invader. B-cells assist in the attack by making antibodies that stick to and flag cells that should be destroyed.

detailed information can be found on this link:
http://www.cancer.gov/about-cancer/treatment/types/immunotherapy