Antibodies are proteins made by the body's natural defence system (immune system) to fight foreign substances, such as bacteria. Antibodies attach themselves to the foreign substance, allowing other immune system cells to attack and destroy the substance.
The surfaces of viruses, fungi, and bacteria contain markers called antigens. To destroy the viruses, fungi, or bacteria, the immune system creates antibodies that are specific for each antigen.
- The first time a person is exposed to a type of bacteria, fungus, or virus, the immune system makes antibodies to that specific organism.
- Some of these antibodies remain in the immune system after they have attacked and destroyed the bacteria, fungus, or virus.
- If a person is exposed to the bacteria, fungus, or virus again, the immune system will "remember" the first exposure. It will quickly reactivate its antibodies and destroy the organism again.
- These antibodies often protect a person from becoming ill when exposed to the bacteria, fungus, or virus again. This is called immunity.
Blood tests can detect antibodies to certain bacteria, fungi, and viruses, such as the viruses that cause chickenpox, HIV infection, hepatitis, and mononucleosis. Some conditions can be diagnosed by detecting antibodies in a person's blood to the virus, fungus, or bacteria that is causing the condition.
Sometimes the body responds to its own tissue as though the tissue was a foreign substance, creating antibodies against the tissue and triggering reactions that cause normal cells to be destroyed. This is called an autoimmune response or autoimmune disease.
Current as of: September 9, 2014
Author: Healthwise Staff
Medical Review: E. Gregory Thompson, MD - Internal Medicine & Anne C. Poinier, MD - Internal Medicine & W. David Colby IV, MSc, MD, FRCPC - Infectious Disease
Public Health Alerts
Public health alerts include information about outbreaks, advisories and product recalls. Click on the links below to read the most recent alerts, or visit our Public Health Alerts web page.
FIND Services and Resources
If you are looking for health services in your community, you can use our directory to FIND hospitals, clinics, and other resources.
To learn more, visit Healthwise.org
© 1995-2015 Healthwise, Incorporated. Healthwise, Healthwise for every health decision, and the Healthwise logo are trademarks of Healthwise, Incorporated.
Is it an emergency?
If you or someone in your care has chest pains, difficulty breathing, or severe bleeding, it could be life-threatening. Call 9-1-1 or the local emergency number immediately. If you are concerned about a possible poisoning or exposure to a toxic substance, call Poison Control now at 1-800-567-8911.