Drugs built on monoclonal antibodies have become a dominant source of drugs in the early part of the twenty-first century. The annual market for these drugs is nearly $100 billion. They work by intensifying—or dulling, as the case may be—the performance of a particular antibody so that the body does a better job of attacking a life-threatening risk, like cancer, or, alternatively, dampening our elegant defenses so that the immune system doesn’t behave so aggressively and cause autoimmunity.
