Anti-Hu CD4, RPA-T4, PE, 25tests

STEMCELL Technologies provides this PE-conjugated mouse monoclonal antibody (clone RPA-T4) raised against human CD4. The antibody recognizes CD4, an approximately 59 kDa single-chain type 1 transmembrane glycoprotein and member of the immunoglobulin superfamily that contains four extracellular Ig-like domains (D1–D4). The RPA-T4 epitope has been localized to the D1 domain, which has a structure resembling an immunoglobulin 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. The antibody is reactive with human and chimpanzee CD4 and was generated in BALB/c mice, with isotype IgG1 kappa; the immunogen was phytohemagglutinin (PHA)-stimulated human peripheral blood mononuclear cells. Binding of the RPA-T4 antibody blocks HIV binding and mixed lymphocyte reaction, 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 is reportedly sensitive to formaldehyde fixation.

Flow cytometry is the verified and reported application. The reagent is formulated 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. It was purified by affinity chromatography and conjugated with PE under optimal conditions, with the solution free of unconjugated PE. The product is stable at 2–8°C when stored undiluted; it should not be frozen and should be protected from prolonged exposure to light. For flow cytometry, the suggested use is ≤ 5 μL per 1 x 10^6 cells in 100 μL, with titration recommended for optimal performance in each application.