Clinical Research Glossary

antigen antigen


A substance that causes the body's immune system to react.

Example of antigen in a sentence

An antigen is something that your body does not recognize and tries to fight.

More Info

The body reacts to an antigen like a virus, bacteria, parasite, or tumor.

Immune reactions include getting a fever, a rash or hives, or feeling sick.

One of the ways that the immune system protects itself from antigens is to produce antibodies.

Other info to think about when joining a study

You may see the term “antigen” in different research study situations. For example you may see it in the title of a research study, in the consent form, or in other study information. During the Covid pandemic, there was a lot of information about antigen tests.

Feel free to ask a member of the study team for more information if you have questions about the term “antigen” being used in a research study.

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