CD4

noun
\ ˌsē-(ˌ)dē-ˈfȯr How to pronounce CD4 (audio) \

Definition of CD4

: a large glycoprotein that is found associated with a T cell receptor especially on the surface of helper T cells and that binds to a major histocompatibility complex molecule on the surface of an antigen-presenting cell to facilitate antigen recognition and T cell activation often used before another noun the CD4 geneCD4 T cells [=T cells bearing CD4 on their surface]

Note: CD4 is a receptor for HIV, and cells of the immune system bearing CD4 on their surface are preferentially infected with the virus and become progressively depleted.

— compare CD8

First Known Use of CD4

1984, in the meaning defined above

History and Etymology for CD4

cluster of differentiation

Keep scrolling for more

Learn More About CD4

Dictionary Entries Near CD4

CD

CD4

CD8

See More Nearby Entries 

Statistics for CD4

Cite this Entry

“CD4.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/CD4. Accessed 16 Oct. 2021.

Style: MLA
MLACheck Mark Icon ChicagoCheck Mark Icon APACheck Mark Icon Merriam-WebsterCheck Mark Icon

Keep scrolling for more

More Definitions for CD4

CD4

noun
\ -ˈfōr, -ˈfȯr How to pronounce CD4 (audio) \

Medical Definition of CD4

: a large glycoprotein that is found associated with a T cell receptor especially on the surface of helper T cells and that binds to a major histocompatibility complex molecule on the surface of an antigen-presenting cell to facilitate antigen recognition and T cell activation often used before another noun the CD4 geneCD4 T cells [=T cells bearing CD4 on their surface]

Note: CD4 is a receptor for HIV and cells of the immune system bearing CD4 on their surface are preferentially infected with the virus and become progressively depleted.

— compare cd8

WORD OF THE DAY

Test Your Vocabulary

Farm Idioms Quiz

  • cow coming home
  • What does 'poke' refer to in the expression 'pig in a poke'?
True or False

Test your knowledge - and maybe learn something along the way.

TAKE THE QUIZ
Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!