Anti-Hu CD4, OKT4, PE, 25tests

This mouse monoclonal IgG2b, kappa antibody from STEMCELL Technologies targets human 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 OKT4 clone's epitope has been localized to the D3 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. It binds to a non-polymorphic region of MHC II, acting as a co-receptor to the T cell receptor (TCR) to enhance the affinity of the association between TCR and MHC II-antigen complex, and amplifies TCR signals through its intracellular domain's interaction with cytoplasmic tyrosine kinases such as Lck. CD4 also functions as a receptor for human immunodeficiency virus (HIV), although binding of the OKT4 antibody to CD4 does not block HIV binding. The antibody shows reactivity with human, rhesus, cynomolgus, chimpanzee, and sooty mangabey samples, was raised against human peripheral blood T lymphocytes, and is PE-conjugated following purification by affinity chromatography.

Verified and reported for flow cytometry, the antibody is formulated as a phosphate-buffered solution at pH 7.2 containing 0.09% sodium azide and 0.2% (w/v) bovine serum albumin, and is free of unconjugated PE and unconjugated antibody. For flow cytometry the suggested use is 5 μL per 1 × 10^6 cells in 100 μL volume or per 100 μL of whole blood, with titration recommended for optimal performance. The product should be stored undiluted at 2 – 8°C; it must not be frozen and should be protected from prolonged exposure to light. It has also been verified for purity assessments of cells isolated with EasySep™ kits, and is supplied as a clear liquid.