Antigen

noun

/ˈæntɪdʒən/

Any substance — typically a protein on the surface of a pathogen — that is recognised as foreign by the immune system and triggers the production of antibodies.

✍️ Usage in a UPSC answer

Just as a healthy body mounts a calibrated defence only when a genuine antigen breaches its barriers, a mature democracy must reserve its coercive apparatus for real threats to public order, lest an overzealous state begin attacking the very citizenry it is meant to protect.

Synonyms

immunogenallergenforeign bodypathogentoxinhapten

Antonyms

antibodyimmunoglobulinantitoxin

🌱 Word Family

antigen (n), antigens (n pl), antigenic (adj), antigenicity (n), antigenically (adv)

🔡 Root

French antigène: anti- (against/antibody) + Greek -genēs (born of, producer); first recorded 1905.

📜 Etymology

From French antigène, from anti- (short for antibody) + -gène (producer, from Greek -genēs, born of); first recorded in 1905 in the Journal of the American Medical Association.

🧠 Memory Hook

Read it as ANTI + GEN = an "antibody generator": the intruder that triggers the body's defenders into action.

⚗️ General Science 📖 Seen in: Microorganisms, Immunology & Vaccines

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