Rat splenocytes are stained with Anti-Rat CD4(domain 1) Monoclonal Antibody(FITC Conjugated)(filled gray histogram). Unstained splenocytes (empty black histogram) are used as control.
CD4, also known as T4, is a 55kD glycoprotein member of the immunoglobin superfamily and is expressed on majority of thymocytes, macrophages, and a peripheral T cell subset (T helper cells). CD4 is a T cell co-receptor that interacts with the MHC class II molecule and is involved in T cell activation.