CD4 Mouse, anti-Human, APC, Clone: RPA-T4, STEMCELL Technologies

Description

• The RPA-T4 antibody reacts with CD4, an ∼59 kDa single-chain type 1 transmembrane glycoprotein and member of the immunoglobulin (Ig) superfamily; CD4 contains four extracellular Ig-like domains (D1 - D4)
• The epitope for RPA-T4 has been localized to the D1 domain of the protein, which has a structure resembling an Ig variable domain
• CD4 is expressed at relatively high levels by most thymocytes and a subpopulation of T cells (T helper cells), and at lower levels by peripheral blood monocytes and macrophages
• CD4 binds to a nonpolymorphic region of MHC II and acts as a co-receptor to the T cell receptor (TCR) in MHC II-restricted antigen recognition by enhancing the affinity of the association between the TCR and MHC II-antigen complex
• CD4 also functions to amplify signals from the TCR to the cytoplasm through the interaction of its intracellular domain with cytoplasmic tyrosine kinases, such as Lck
• Moreover, CD4 is a receptor for the human immunodeficiency virus (HIV)
• Binding of the RPA-T4 antibody blocks HIV binding and mixed lymphocyte reaction (MLR), and inhibits the activation of CD4+ T cells in vitro by interfering with the association of CD4 and HLA-DR
• It also partially blocks the binding of antibody clone SK3
• The epitope of the RPA-T4 antibody is reportedly sensitive to formaldehyde fixation