Antigen vs. Antibody

Antigennoun

(immunology) A substance that induces an immune response, usually foreign.

Antigennoun

any substance (as a toxin or enzyme) that stimulates the production of antibodies

Antigennoun

a toxin or other foreign substance which induces an immune response in the body, especially the production of antibodies.

Antigen

In immunology, an antigen (Ag) is a molecule or molecular structure, such as may be present on the outside of a pathogen, that can be bound by an antigen-specific antibody or B-cell antigen receptor. The presence of antigens in the body normally triggers an immune response.

Antibodynoun

(immunology) A protein produced by B-lymphocytes that binds to a specific antigen.

Antibodynoun

Any of various bodies or substances in the blood which act in antagonism to harmful foreign bodies, as toxins or the bacteria producing the toxins. Normal blood serum apparently contains various antibodies, and the introduction of toxins or of foreign cells also stimulates production of their specific antibodies by the immune system.

Antibodynoun

more narrowly, any of the immunoglobulins present in the blood serum or other body fluids of an animal, which reacts with a specific antigenic substance, whether the antibody was produced as a consequence of the stimulus provided by the antigen, or was pre-existing prior to exposure of the organism to the antigen.

Antibodynoun

any of a large variety of proteins normally present in the body or produced in response to an antigen which it neutralizes, thus producing an immune response

Antibodynoun

a blood protein produced in response to and counteracting a specific antigen. Antibodies combine chemically with substances which the body recognizes as alien, such as bacteria, viruses, and foreign substances in the blood.

Antibody

An antibody (Ab), also known as an immunoglobulin (Ig), is a large, Y-shaped protein used by the immune system to identify and neutralize foreign objects such as pathogenic bacteria and viruses. The antibody recognizes a unique molecule of the pathogen, called an antigen.