CD4 (cluster of differentiation 4) (CD4)

CD4 is a transmembrane glycoprotein expressed predominantly on the surface of helper T lymphocytes, and to a lesser extent on monocytes, macrophages, and dendritic cells. It acts as a co-receptor for MHC class II molecules, and is essential for the activation and differentiation of T cells during adaptive immune responses. CD4 facilitates cell signaling required for immune cell interactions, cytokine production, and B cell activation. It is also the primary receptor for HIV entry, making it a crucial therapeutic target in immunology and infectious disease. CD4^+ T cell subsets can differentiate into specialized effector functions (Th1, Th2, Th17, Treg, etc.), which orchestrate tailored immune responses to diverse pathogens and environmental stimuli.

Other names

Helper T cell antigenCD4 antigenCluster of differentiation 4T-helper cell antigenCD4^+ T cell surface moleculeT4 antigen (historical)

Inhibition of CD4/HIV gp120 interaction (prevents HIV entry into helper T cells); Modulation of immune response by blocking, stimulating, or depleting CD4^+ cells; Targeted depletion of CD4^+ cells for immunosuppression in transplantation or autoimmune disorders