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designation for an antigen found on helper T cells; see under antigen.
a type I transmembrane protein found on helper/inducer T cells, monocytes, macrophages, and dendritic cells that is involved in T-cell recognition of antigens; expressed in mycosis fungoides, Sézary syndrome, and T-cell lymphomas.
A glycoprotein predominantly found on the surface of helper T cells. In humans, it is a receptor for HIV, enabling the virus to gain entry into its host.
CD4A transmembrane glycoprotein present on T helper/inducer cells, which participates in adherence of T cells to target cells, and is involved in thymic maturation and transmission of intracellular signals during T cell activation by the class II MHC; CD4 has inducer or helper activity for T cell, B cell, and macrophage interactions, and evokes T cell proliferation in response to soluble antigens or autologous non-T cells, providing appropriate signals for B cell proliferation and differentiation into Ig-secreting cells; CD4 is also a high-affinity receptor for HIV-1's gp120, binding 42–55 of the NH2 terminal domain amino acids, and has an Ig-like fold similar to the complementarity-determining region of the kappa light chain; CD4 also binds Igs independently of the Fc receptor, and is an accessory to the T-cell receptor
A type of protein molecule in human blood that is present on the surface of 65% of human T cells. CD4 is a receptor for the HIV virus. When the HIV virus infects cells with CD4 surface proteins, it depletes the number of T cells, B cells, natural killer cells, and monocytes in the patient's blood. Most of the damage to an AIDS patient's immune system is done by the virus' destruction of CD4+ lymphocytes. CD4 is sometimes called the T4 antigen.