SpecificityRecognizes a determinant designated L3T4 present on mouse T-cell surface with an apparent molecular mass of 52kDa. The L3T4 antigen is expressed by the helper/inducer subset of mouse T-cells. The antigen is present on approximately 80% of thymocytes, 20% of spleen cells and 60% of lymph node cells. The expression of L3T4 correlates with class II MHC antigen reactivity on cloned T-cell lines.
Post-translational modificationsPalmitoylation and association with LCK contribute to the enrichment of CD4 in lipid rafts.
Cellular localizationCell membrane. Localizes to lipid rafts. Removed from plasma membrane by HIV-1 Nef protein that increases clathrin-dependent endocytosis of this antigen to target it to lysosomal degradation. Cell surface expression is also down-modulated by HIV-1 Envelope polyprotein gp160 that interacts with, and sequesters CD4 in the endoplasmic reticulum.