Antigen vs. Pathogen

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.

Pathogennoun

Any organism or substance, especially a microorganism, capable of causing disease, such as bacteria, viruses, protozoa or fungi. Microorganisms are not considered to be pathogenic until they have reached a population size that is large enough to cause disease.

Pathogennoun

Any microorganism which causes disease; a pathogenic organism; an infectious microorganism; a bacterium, virus, or other agent which can cause disease by infection; - opposed to zymogene. The spelling pathogene is now archaic.

Pathogennoun

any disease-producing agent (especially a virus or bacterium or other microorganism)

Pathogen

In biology, a pathogen (Greek: πάθος pathos , and -γενής -genēs ) in the oldest and broadest sense, is any organism that can produce disease. A pathogen may also be referred to as an infectious agent, or simply a germ.