Mouse splenocytes are stained with Anti-Mouse CD4 Monoclonal Antibody(PercP Conjugated)[Used at 0.05 μg/106 cells dilution](filled gray histogram). Unstained splenocytes (blank black histogram) are used as control.
CD4 is a 55 kD protein also known as L3T4 or T4. It is a member of the Ig superfamily, primarily expressed on most thymocytes, a subset of T cells, and weakly on macrophages and dendritic cells. It acts as a coreceptor with the TCR during T cell activation and thymic differentiation by binding MHC class II and associating with the protein tyrosin kinase, lck.