antigen

noun

an·​ti·​gen ˈan-ti-jən How to pronounce antigen (audio)
-ˌjen
: any substance (such as an immunogen or a hapten) foreign to the body that evokes an immune response either alone or after forming a complex with a larger molecule (such as a protein) and that is capable of binding with a product (such as an antibody or T cell) of the immune response
antigenic adjective
antigenically adverb
antigenicity noun

Did you know?

An antibody is a protein produced by your immune system to fight outside invaders. Since the enemy substance actually triggers the production of antibodies, such substances are called antigens—anti- being short for antibody, and -gen meaning "producer". (In a similar way, an allergen produces an allergy, and a pathogen produces a pathology or disease.) Antigens are often rodlike structures that stick out from the surface of an invading organism—usually a bacterium or a virus—and allow it to attach itself to cells in the invaded body. But unfortunately for them, in doing so they let the immune system know they're present, and the body is flooded with an army of Pac-Man-like antibodies.

Examples of antigen in a Sentence

Recent Examples on the Web The tests are rapid antigen COVID-19 tests that can be taken at home. Sarah Volpenhein, Journal Sentinel, 7 Mar. 2024 Schoenberger said the next path of exploration is to explore ways that antigens that activate CD4 and CD8 T-cells could be linked. Paul Sisson, San Diego Union-Tribune, 6 Mar. 2024 Ordering online Any residential household in the U.S. can go to the USPS website to order up to four rapid antigen COVID-19 tests. Irene Wright, Miami Herald, 6 Mar. 2024 Yet the strategy seemingly panned out: HIM has never contracted COVID, researchers concluded based on antigen tests, PCR tests, and bloodwork. Jacob Stern, The Atlantic, 6 Mar. 2024 The authors of the report wrote that patients with persistent false-positive results and a history of autoimmune disease with rheumatoid factor may benefit from repeat COVID testing with a different brand of rapid antigen test. Alyssa Hui, Verywell Health, 1 Mar. 2024 In May 2020, Quidel received the first emergency use authorization from the U.S. Food and Drug Administration for its at-home COVID-19 antigen test. Natallie Rocha, San Diego Union-Tribune, 22 Feb. 2024 The professor of medicine, now Vice Chair of Hematology and director of Blood Marrow and Transplantation and Cellular Therapies at Mayo Clinic, set big goals — aiming to pioneer one of the most advanced therapies for combating blood cancers: chimeric antigen receptor T-cell therapy (CAR-T therapy). Melissa Karns, USA TODAY, 4 Jan. 2024 While polymerase chase reaction, or PCR, COVID tests are more accurate that rapid antigen tests, they must be administered by a skilled laboratory technician, require special equipment and take up to an hour or more to process. Angela Roberts, Baltimore Sun, 14 Feb. 2024

These examples are programmatically compiled from various online sources to illustrate current usage of the word 'antigen.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.

Word History

Etymology

German, from French antigène, from anticorps antibody + -gène -gen

First Known Use

1908, in the meaning defined above

Time Traveler
The first known use of antigen was in 1908

Dictionary Entries Near antigen

Cite this Entry

“Antigen.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/antigen. Accessed 19 Mar. 2024.

Kids Definition

antigen

noun
an·​ti·​gen ˈant-i-jən How to pronounce antigen (audio)
-ˌjen
: a substance (as a protein) that causes the body to form antibodies against it when it is introduced into the body either alone or as part of a microscopic plant or animal
antigenic adjective

Medical Definition

antigen

noun
an·​ti·​gen ˈant-i-jən How to pronounce antigen (audio)
: any substance (as an immunogen or a hapten) foreign to the body that evokes an immune response either alone or after forming a complex with a larger molecule (as a protein) and that is capable of binding with a product (as an antibody or T cell) of the immune response
antigenic adjective
antigenically adverb

More from Merriam-Webster on antigen

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