: a small separable part of an antigen that reacts specifically with an antibody but is incapable of stimulating antibody production except in combination with a carrier protein molecule

Word History

Etymology

borrowed from German Hapten, from Greek hapt- (stem of háptein "to fasten," háptesthai "to fasten oneself onto, grasp") + German -en (in Antigen antigen) — more at haptics

Note: Term introduced by Karl landsteiner in "Über heterogenetisches Hapten und Antigen," Biochemische Zeitschrift, Band 119 (1921), pp. 294-306.

First Known Use

1921, in the meaning defined above

Time Traveler
The first known use of hapten was in 1921

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Cite this Entry

“Hapten.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/hapten. Accessed 26 Mar. 2025.

Medical Definition

: a small separable part of an antigen that reacts specifically with an antibody but is incapable of stimulating antibody production except in combination with an associated protein molecule

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