Antibody
A protein that binds to something foreign in the body and marks it for attack. One of the central tools of the immune system.
In 1890 Emil von Behring and Shibasaburo Kitasato showed that serum from animals made resistant to tetanus or diphtheria could protect other animals from the disease[1]. Something that neutralised the toxin had formed in the blood. That something later came to be called antibody.
An antibody binds only to one particular shape on its target, the antigen, like a key in a lock. Antibodies protect against infection, but when they bind to the cells of a transplanted organ they trigger an attack on it. The first problem in putting a pig organ into a person is the antibody against pig sugar chains that humans carry from the start.
Related terms
- Antibody-mediated rejectionRejection in which the recipient produces antibodies against a transplanted organ, and those antibodies attack the organ's blood vessels and gradually impair it.
- Carbohydrate antigenA sugar chain on the cell surface that the immune system uses as a target. In xenotransplantation the key example is α-Gal, present in pigs but absent in humans.
- ImmunosuppressionUsing drugs to weaken the immune system so that it does not reject a transplanted organ.