CD4 gene encodes the CD4 membrane glycoprotein of T lymphocytes. The CD4 antigen acts as a coreceptor with the T-cell receptor on the T lymphocyte to recognize antigens displayed by an antigen presenting cell in the context of class II MHC molecules. The CD4 antigen is also a primary receptor for entry of the human immunodeficiency virus through interactions with the HIV Env gp120 subunit. This gene is expressed not only in T lymphocytes, but also in B cells, macrophages, granulocytes, as well as in various regions of the brain. The protein functions to initiate or augment the early phase of T-cell activation, and may function as an important mediator of indirect neuronal damage in infectious and immune-mediated diseases of the central nervous system. Multiple alternatively spliced transcript variants encoding different isoforms have been identified in this gene.
Protein expression analysis
Strain specific CD4 expression analysis in heterozygous B-hCD4 mice by flow cytometry. Thymocytes were collected from wild type C57BL/6 (+/+) and heterozygous B-hCD4 mice (H/+) and analyzed by flow cytometry with species-specific anti-CD4 antibody. Mouse CD4 was detectable in WT mice and heterozygous B-hCD4 mice. Human CD4 was exclusively detectable in heterozygous B-hCD4 mice but not in WT mice.