antigen Definition
a toxin or other foreign substance that induces an immune response in the body, especially the production of antibodies.
Using antigen: Examples
Take a moment to familiarize yourself with how "antigen" can be used in various situations through the following examples!
Example
The antigen on the surface of the virus triggers an immune response.
Example
Vaccines work by introducing a harmless form of the antigen into the body to stimulate antibody production.
Example
Blood typing is based on the presence or absence of certain antigens on the surface of red blood cells.
Phrases with antigen
self-antigen
an antigen that originates from within the body, rather than from an external source
Example
Autoimmune diseases occur when the immune system attacks self-antigens.
cross-reactive antigen
an antigen that shares structural similarities with another antigen, leading to an immune response against both antigens
Example
Some vaccines may produce cross-reactive antigens that provide protection against multiple strains of a virus.
Example
Immunotherapy drugs target tumor antigens to help the immune system recognize and attack cancer cells.
Origins of antigen
from Greek 'anti-' meaning 'against' and 'genos' meaning 'race, kind'
Summary: antigen in Brief
An 'antigen' [ˈæntɪdʒən] is a toxin or other foreign substance that induces an immune response in the body, especially the production of antibodies. Vaccines work by introducing a harmless form of the antigen into the body to stimulate antibody production. Blood typing is based on the presence or absence of certain antigens on the surface of red blood cells. Phrases like 'self-antigen,' 'cross-reactive antigen,' and 'tumor antigen' refer to specific types of antigens.
