Sigma-Aldrich Anti-Cd4 Clone Sk3 25 Mig

T-cell surface glycoprotein CD4 (UniProt: P01730; also known as T-cell surface antigen T4/Leu-3, CD4) is encoded by the CD4 gene (Gene ID: 920) in human. CD4 is a single-pass type I membrane glycoprotein that is highly expressed in T-helper cells and is also found in macrophages, dendritic cells, and NK cells. CD4 is synthesized with a signal peptide (a 1-25), which is subsequently cleaved off to generate the mature form that has an extracellular domain (aa 26-396), a transmembrane domain (aa 397-418), and a cytoplasmic domain (aa 419-458). It has three Ig-like C2-type and one Ig-like V-type domain. CD4 plays an essential role in the immune response and serves multiple functions in response against both external and internal offenses. In T-cells, it functions primarily as a coreceptor for MHC class II molecule:peptide complex. It interacts simultaneously with the T-cell receptor (TCR) and the MHC class II presented by antigen presenting cells and recruits the Src kinase LCK to the vicinity of the TCR-CD3 complex. The LCK can then initiate different intracellular signaling events by phosphorylating various substrates, which lead to lymphokine production, motility, adhesion and activation of T-helper cells. CD4 is also reported to participates in the development of T-helper cells in the thymus and trigger the differentiation of monocytes into functional mature macrophages. CD4 also serves a primary receptor for human immunodeficiency virus-1 (HIV-1). It is removed from plasma membrane by Nef protein of HIV-1, which increases clathrin-dependent endocytosis and lysosomal degradation of CD4.

Human peripheral blood T lymphocytes.

Quality Control Testing

Evaluated by Flow Cytometry in human peripheral blood mononuclear cells (PBMC).

Flow Cytometry Analysis: 1.0 µg from a representative lot detected CD4/Leu3 in human peripheral blood mononuclear cells (PBMC).

Tested Applications

Immunohistochemistry Applications: A representative lot detected CD4 in Immunohistochemistry applications (Tjin, E.P.M., et Al. (2014). Cancer Immunol Res. 2(6):538-46).

Flow Cytometry Analysis: A representative lot detected CD4 in Flow Cytometry applications (Evans, R.L., et Al. (1981). Proc Natl Acad Sci USA. 78(1):544-8; Mold, J.E., et Al. (2021). Cell Rep. 35(8):109174).

Note: Actual optimal working dilutions must be determined by end user as specimens, and experimental conditions may vary with the end user.

Clone SK3 is a mouse recombinant monoclonal antibody that detects CD4. It targets an epitope from the extracellular domain.

Purified mouse monoclonal antibody IgG1 in buffer containing 0.1 M Tris-Glycine (pH 7.4), 150 mm NaCl with 0.05% sodium azide.

0.5 mg/mL. Please refer to guidance on suggested starting dilutions and/or titers per application and sample type.

Recommended storage: +2°C to +8°C.

Concentration: Please refer to the Certificate of Analysis for the lot-specific concentration.

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