killer cell


: a lymphocyte (such as a killer T cell or a natural killer cell) with cytotoxic activity

Example Sentences

Recent Examples on the Web Last year, the researchers announced that natural-killer cell activity, CD8 T-cell counts and other immune functions improved significantly with the treatment. Kenneth Miller, Discover Magazine, 30 May 2013 The group of immune cells that surge during and after short bouts of exercise, which include neutrophils and natural-killer cells, serve as our frontline defense against invading viruses. Katarina Zimmer, Outside Online, 27 Mar. 2020 The checkpoint inhibitors allow powerful immune cells to recognize and hone in on cancer cells and co-opt killer cells to destroy them. Alice Park, Time, 12 July 2018

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

Word History

First Known Use

1972, in the meaning defined above

Time Traveler
The first known use of killer cell was in 1972

Dictionary Entries Near killer cell

Cite this Entry

“Killer cell.” Dictionary, Merriam-Webster, Accessed 9 Jun. 2023.

Medical Definition

killer cell

: a lymphocyte (as a cytotoxic T cell or a natural killer cell) with cytotoxic activity
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