First Time User? Enroll now.
*Vaccine availability and appointments* | Visitor and mask policies | Additional COVID-19 resources.
Home > Health Library > Antigen
An antigen is a substance (such as part of a virus or bacteria) that triggers the immune system to produce cells (antibodies) that attack and try to destroy the antigen. The body usually produces one specific type of antibody for each antigen.
Sometimes the body mistakenly recognizes its own tissue as an antigen or foreign substance and produces antibodies against its own tissue. This is called an autoimmune response or autoimmune disease.
Current as of: December 9, 2019
Author: Healthwise Staff
Medical Review:E. Gregory Thompson MD - Internal Medicine & Adam Husney MD - Family Medicine & Martin J. Gabica MD - Family Medicine
To learn more about Healthwise, visit Healthwise.org.
© 1995-2020 Healthwise, Incorporated. Healthwise, Healthwise for every health decision, and the Healthwise logo are trademarks of Healthwise, Incorporated.