antigen
noun
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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
Alice Oglethorpe, SELF, 18 July 2025
Scripps Research explores ‘switchable’ sells to help with tumor treatment
A new approach at Scripps Research in La Jolla is using a combination of medications to create a version of chimeric antigen receptor, or CAR, T-cell therapy.
—Noah Lyons, San Diego Union-Tribune, 15 July 2025
Individuals who test positive for Epstein–Barr virus (EBV) capsid antigen (VCA-IgA) antibodies were found to have a higher risk of developing cancers such as lung cancer, liver cancer, nasopharyngeal carcinoma and lymphoma, according to a study shared by IARC with Newsweek.
—Jasmine Laws, MSNBC Newsweek, 10 July 2025
High-dose flu vaccine: Contains 4 times the amount of antigen — the part of the vaccine that helps your body build up protection against influenza viruses — as a regular inactivated flu shot to help create a stronger immune response.
—Chris Sims, Louisville Courier Journal, 16 Jan. 2025
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Cite this Entry
“Antigen.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/antigen. Accessed 5 Aug. 2025.
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antigen
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antigen
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