CD4 molecule (CD4)

The CD4 molecule is a glycoprotein expressed on the surface of helper T (T_h) cells, monocytes, macrophages, and dendritic cells. It acts as a co-receptor for the T cell receptor (TCR) during antigen recognition by binding to MHC class II molecules on antigen-presenting cells. CD4 T-helper cells play a central role in orchestrating the adaptive immune response by helping activate B cells, cytotoxic T cells, and macrophages via cytokine secretion and cell-cell interactions. Stimulation of CD4 T-helper cells involves TCR engagement with antigen-MHC II complexes, co-receptor CD4 binding, co-stimulatory signals (e.g., CD28-CD80/86 interactions), and the integration of cytokine-driven differentiation pathways. This coordinated activation determines immune polarization and is critical for effective immunity, but dysregulation can contribute to infection susceptibility, autoimmunity, and immunopathology.

Other names

CD4 antigenT4 antigenLeu-3

Modulation or blockade of CD4-mediated T cell activation, inhibition of HIV entry via gp120-CD4 interaction, immune suppression/modulation