antibody an·ti·bod·y (ān'tĭ-bŏd'ē)
n.
Abbr. Ab A protein substance produced in the blood or tissues in response to a specific antigen, such as a bacterium or a toxin, that destroys or weakens bacteria and neutralizes organic poisons, thus forming the basis of immunity.
An immunoglobulin present in the blood serum or body fluids as a result of antigenic stimulus and interacting only with the antigen that induced it or with an antigen closely related to it.
Proteins in the blood that are produced by the body in response to specific antigens (such as bacteria). (See immune system.)