Antibody therapy is a type of treatment that uses antibodies to target and destroy specific cells or proteins in the body. It is used to treat a variety of diseases, including cancer, autoimmune diseases, and infectious diseases. Antibodies are proteins produced by the body's immune system to recognize and fight foreign substances, such as bacteria and viruses. In antibody therapy, the antibodies are either produced in a laboratory or taken from a donor and then injected into the patient. The antibodies then bind to the target cells or proteins and either destroy them directly or recruit other immune cells to do so.