: a glycoprotein that is found associated with a T cell receptor especially on the surface of a cytotoxic T cell and that binds to a major histocompatibility complex molecule on the surface of an antigen-presenting cell to facilitate antigen recognition and cytotoxic T cell activation
often used before another noun
CD8 surface markers
CD8 cells [=cells bearing CD8 on their surface]
… the CD8 molecule is closely associated with MHC class I molecules on antigen-presenting cells.Scientific American Medicine
compare CD4

Examples of CD8 in a Sentence

Recent Examples on the Web Schoenberger said the next path of exploration is to explore ways that antigens that activate CD4 and CD8 T-cells could be linked. Paul Sisson, San Diego Union-Tribune, 6 Mar. 2024 In the last few years, some in the field have thought tumor-fighting CD8+ T cells come in to suppress the disease-causing immune response of CD4+ cells. Isabella Cueto, STAT, 14 July 2023 When the adaptive response starts taking effect, CD4+ and CD8+ T-cells are released which play an important role in coordinating a sustained immune response and killing off infected cells. William A. Haseltine, Forbes, 13 Feb. 2023 The scientists looked for antibodies, memory B cells, CD8+ T cells, and CD4+ T cells, all fighting SARS-CoV-2. Adam Rogers, Wired, 5 Mar. 2021 More intriguing, most of these active mice had been inoculated with cancer cells that are known to be particularly vulnerable to a specific type of immune cell, known as CD8+ T cells, which tend, primarily, to fight certain forms of breast cancer and other solid tumors. Gretchen Reynolds, Star Tribune, 21 Nov. 2020 Yet in essence, two different immune cells—known as helper T (or CD4+) cells and killer T (or CD8+) cells—and molecules known as human leukocyte antigen (HLA) receptors—seem to play the most important roles. Bruce D. Walker, Scientific American, 1 July 2012

These examples are programmatically compiled from various online sources to illustrate current usage of the word 'CD8.' 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

1984, in the meaning defined above

Time Traveler
The first known use of CD8 was in 1984

Dictionary Entries Near CD8

Cite this Entry

“CD8.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/CD8. Accessed 20 Apr. 2024.

Medical Definition

: a glycoprotein that is found associated with a T cell receptor especially on the surface of a cytotoxic T cell and that binds to a major histocompatibility complex molecule on the surface of an antigen-presenting cell to facilitate antigen recognition and cytotoxic T cell activation
often used before another noun
CD8 surface markers
CD8 cells [=cells bearing CD8 on their surface]
… the CD8 molecule is closely associated with MHC class I molecules on antigen-presenting cells.Scientific American Medicine
compare cd4
Last Updated: - Updated example sentences
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