self antigen

biochemistry

Also known as: autoantigen

Written by

The Information Architects of Encyclopaedia Britannica

Last updated

July 17, 2026

Quick Summary

A self-antigen is a substance originating within the body that can trigger an immune response. Normally, the immune system distinguishes between the body's own components (self) and foreign invaders (nonself). This tolerance is maintained through mechanisms that eliminate or inactivate self-reactive lymphocytes.12

However, in individuals with autoimmune disorders, this self-regulatory process fails. Self-antigens can be altered, making them appear foreign to the immune system, or the mechanisms preventing autoimmunity may malfunction. This can lead to the production of autoantibodies, which are antibodies that mistakenly attack the body's own healthy cells and tissues.34

Summary created from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.

4 Britannica Sources

Ask Britannica AI about this topic

Britannica doesn't have a full article on this topic, so we've curated a list of our relevant coverage.

immune system disorder
Alteration of self antigens
Various mechanisms can alter self components so that they seem foreign to the immune system. New antigenic determinants can be attached to self proteins, or the shape of a self antigen can shift—for a variety of reasons—so that previously unresponsive helper T cells…
Read More
Various mechanisms can alter self components so that they seem foreign to the immune system. New antigenic determinants can be attached to self proteins, or the shape of a self antigen can shift—for a variety of reasons—so that previously unresponsive helper T cells…
Read More

antigen
…(or heteroantigens) and autoantigens (or self-antigens). Foreign antigens originate from outside the body. Examples include parts of or substances produced by viruses or microorganisms (such as bacteria and protozoa), as well as substances in snake venom, certain proteins in foods, and components of serum and red blood cells from other…
Read More
…(or heteroantigens) and autoantigens (or self-antigens). Foreign antigens originate from outside the body. Examples include parts of or substances produced by viruses or microorganisms (such as bacteria and protozoa), as well as substances in snake venom, certain proteins in foods, and components of serum and red blood cells from other…
Read More