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A glycoprotein that is found on the surface of T cells, especially helper T cells, and functions as a receptor in activation of the cells. In humans, HIV gains entry to helper T cells by binding to the CD4 receptor.
[c(luster of) d(ifferentiation antigen) 4.]
a protein on the surface of T cells and other cells, functioning as a receptor for the AIDS virus antigen.
[1980–85; c(luster of) d(ifferentiation) 4]