noun, often attrib \-ˈfōr, -ˈfr\

Definition of CD4

: a large glycoprotein that is found especially on the surface of helper T cells, that is the receptor for HIV, and that usually functions to facilitate recognition by helper T cell receptors of antigens complexed with molecules of a class that are found on the surface of antigen-presenting cells (as B cells and macrophages) and are the product of genes of the major histocompatibility complex

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