Anti-Hu CD4, RPA-T4, PE, 500tests

Produced by STEMCELL Technologies, this PE-conjugated mouse monoclonal antibody (clone RPA-T4, IgG1 kappa) is directed against human and chimpanzee CD4, a ~59 kDa single-chain type 1 transmembrane glycoprotein and member of the immunoglobulin superfamily. CD4 contains four extracellular Ig-like domains (D1 - D4), and the RPA-T4 epitope maps to the D1 domain, which has a structure resembling an Ig variable domain. CD4 is expressed at relatively high levels by most thymocytes and a subpopulation of peripheral T cells (T helper cells), and at lower levels by peripheral blood monocytes and macrophages.

The antibody was generated in BALB/c mice against phytohemagglutinin (PHA)-stimulated human peripheral blood mononuclear cells. CD4 binds to a nonpolymorphic region of MHC class II and acts as a co-receptor to the T cell receptor (TCR) in MHC II-restricted antigen recognition; its intracellular domain interacts with cytoplasmic tyrosine kinases such as Lck to amplify TCR signals. CD4 also serves as a receptor for human immunodeficiency virus (HIV). RPA-T4 binding blocks HIV attachment and the mixed lymphocyte reaction (MLR), and inhibits the in vitro activation of CD4+ T cells by interfering with the CD4/HLA-DR association; it also partially blocks binding of clone SK3. The RPA-T4 epitope is reportedly sensitive to formaldehyde fixation.

Verified and reported for flow cytometry, the reagent has also been validated for purity assessments of cells isolated with EasySep™ kits, including the Human CD4+CD127lowCD25+ Regulatory T Cell Isolation Kit, Human ILC2 Isolation Kit, and Human Central and Effector Memory CD4+ T Cell Isolation Kit. For flow cytometry, the suggested use is ≤ 5 μL per 1 x 10^6 cells in 100 μL, with titration recommended for each application. The antibody is supplied in phosphate-buffered saline (pH 7.2) containing 0.09% sodium azide, 0.1% gelatin, and less than 0.2% (w/v) bovine serum albumin, and is free of unconjugated PE following affinity chromatography purification. The product is stable at 2 - 8°C when stored undiluted; do not freeze, and protect from prolonged exposure to light. For research use only.