cytokine

noun

cy·​to·​kine ˈsī-tə-ˌkīn How to pronounce cytokine (audio)
plural cytokines
: any of a class of immunoregulatory proteins (such as interleukin or interferon) that are secreted by cells especially of the immune system
Most cytokines are produced primarily in the presence of disease or immunization and contribute to immune responses, inflammation, and endothelial cell activation; others are involved in tissue repair.Charles A. Dinarello et al.
The proinflammatory cytokine interleukin-2 determines the magnitude and duration of the T-cell response immediately after antigen encounter and assists in the maturation of macrophages and the proliferation of B cells and natural killer cells …Chiea C. Khor et al.

Examples of cytokine in a Sentence

Recent Examples on the Web
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The researchers looked at cortisol (a stress hormone) levels and levels of cytokines, signaling proteins that modulate the immune response, including inflammation. New Atlas, 12 Apr. 2025 There was also evidence of uncontrolled inflammatory response in the brains of older rats after three days, identified through a change in levels of proteins known as cytokines. Stephanie Edwards, Discover Magazine, 7 Mar. 2025 Eggs Eating enough protein is essential for immune health because protein is necessary for producing antibodies and cytokines. Jillian Kubala, Health, 16 Dec. 2024 The signals do this by telling certain immune cells to stop producing inflammatory proteins called cytokines. Jon Hamilton, NPR, 3 Feb. 2025 See All Example Sentences for cytokine

Word History

Etymology

cyt- + -kine (as in lymphokine)

First Known Use

1974, in the meaning defined above

Time Traveler
The first known use of cytokine was in 1974

Cite this Entry

“Cytokine.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/cytokine. Accessed 2 May. 2025.

Medical Definition

cytokine

noun
cy·​to·​kine ˈsīt-ə-ˌkīn How to pronounce cytokine (audio)
: any of a class of immunoregulatory proteins (as interleukin, tumor necrosis factor, and interferon) that are secreted by cells especially of the immune system

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