CD4

noun

ˌsē-(ˌ)dē-ˈfȯr 

: 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 gene

CD4 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 History

Etymology

cluster of differentiation

First Known Use

1984, in the meaning defined above

Medical Definition

CD4

noun

-ˈfōr, -ˈfȯr 

: 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 gene

CD4 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