Anti-Hu CD4, OKT4, PE, 100tests

This mouse monoclonal antibody from STEMCELL Technologies, clone OKT4, is conjugated to PE and recognizes CD4, a member of the immunoglobulin superfamily. CD4 is an approximately 59 kDa single-chain type 1 transmembrane glycoprotein containing four extracellular Ig-like domains (D1 – D4). The OKT4 epitope has been localized to the D3 domain, which has a conformation 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. It binds a non-polymorphic region of MHC II, acting as a co-receptor for the T cell receptor (TCR) in MHC II-restricted antigen recognition, and amplifies TCR signals through the interaction of its intracellular region with cytoplasmic tyrosine kinases such as Lck. CD4 also serves as a receptor for human immunodeficiency virus (HIV); binding of the OKT4 antibody to CD4 does not block HIV binding.

The reagent is of the Mouse IgG2b, kappa isotype, raised against human peripheral blood T lymphocytes, with confirmed species reactivity toward human, rhesus, cynomolgus, chimpanzee, and sooty mangabey. It is verified and reported for flow cytometry. This clone has been verified for purity assessments of cells isolated with EasySep™ kits, including the EasySep™ Direct Human CD4+ T Cell Isolation Kit, the EasySep™ Human CD4+ T Cell Enrichment Kit, the EasySep™ Human CD3 Positive Selection Kit, and the EasySep™ Human CD4 Positive Selection Kit, where partial blocking may be observed with the latter. The antibody was purified by affinity chromatography and conjugated with PE under optimal conditions; the solution is free of unconjugated PE and unconjugated antibody.

The product is supplied as a clear liquid in a phosphate-buffered solution at pH 7.2, containing 0.09% sodium azide and 0.2% (w/v) bovine serum albumin. For flow cytometry, the suggested use is 5 μL per 1 x 10^6 cells in 100 μL volume, or per 100 μL of whole blood; titration is recommended for optimal performance in each application. The antibody is stable at 2 – 8°C when stored undiluted; it should not be frozen and should be protected from prolonged exposure to light.