CD4 Protein (hFc Tag)

• Description:

  T-cell surface glycoprotein CD4, is a single-pass type I membrane protein. CD4 contains three Ig-like C2-type (immunoglobulin-like) domains and one Ig-like V-type (immunoglobulin-like) domain. CD4 is a glycoprotein expressed on the surface of T helper cells, regulatory T cells, monocytes, macrophages, and dendritic cells. The CD4 surface determinant, previously associated as a phenotypic marker for helper/inducer subsets of T lymphocytes, has now been critically identified as the binding/entry protein for human immunodeficiency viruses (HIV) . The human CD4 molecule is readily detectable on monocytes, T lymphocytes, and brain tissues. All human tissue sources of CD4 bind radiolabeled gp120 to the same relative degree; however, the murine homologous protein, L3T4, does not bind the HIV envelope protein. CD4 is a co-receptor that assists the T cell receptor (TCR) to activate its T cell following an interaction with an antigen-presenting cell. Using its portion that resides inside the T cell, CD4 amplifies the signal generated by the TCR. CD4 interacts directly with MHC class II molecules on the surface of the antigen-presenting cell via its extracellular domain. The CD4 molecule is currently the object of intense interest and investigation both because of its role in normal T-cell function, and because of its role in HIV infection. CD4 is a primary receptor used by HIV-1 to gain entry into host T cells. HIV infection leads to a progressive reduction of the number of T cells possessing CD4 receptors. Viral protein U (VpU) of HIV-1 plays an important role in downregulation of the main HIV-1 receptor CD4 from the surface of infected cells. Physical binding of VpU to newly synthesized CD4 in the endoplasmic reticulum is an early step in a pathway leading to proteasomal degradation of CD4. Amino acids in both helices found in the cytoplasmic region of VpU in membrane-mimicking detergent micelles experience chemical shift perturbations upon binding to CD4, whereas amino acids between the two helices and at the C-terminus of VpU show no or only small changes, respectively. Paramagnetic spin labels were attached at three sequence positions of a CD4 peptide comprising the transmembrane and cytosolic domains of the receptor. VpU binds to a membrane-proximal region in the cytoplasmic domain of CD4.

• Synonyms:

  CD4mut Protein; IMD79 Protein; Leu-3 Protein; OKT4D Protein; T4 Protein

• Accession Number:

  NP_000607.1

• Reactivity:

  Human

• Cross Reactivity:

  Human

• Label:

  HFc-Tag

• Assay Protocol:

  See Datasheet send with the product

• Endotoxin:

  < 1.0 EU per μg of the protein as determined by the LAL method

• Purity:

  ≥ 95 % as determined by SDS-PAGE. ≥ 90 % as determined by SEC-HPLC.

• Bioactivity:

  1.Measured by the ability of the immobilized protein to support the adhesion of NIH-3T3 mouse embryonic fibroblast cells. When 5x10^4 cells/well are added to CD4-Fc-coated plates (1.25μg/mL, 100 μL/well), approximately 20%-50% cells will adhere after 30 minutes at 37°C. 2.Immobilized Recombinant HIV-1 gp140 Protein (group M, subtype CRF07_BC) at 2 μg/mL (100 μL/well) can bind Recombinant Human CD4 Protein, the EC50 is 70-210 ng/mL. 3.Loaded Recombinant Human CD4 Protein on ProA Biosensor, can bind HIV-1 gp140 Protein (group M, subtype CRF07_BC), with an affinity constant of 82.3nM as determined in BLI assay (Sartorius Octet Red384) . 4.Immobilized Recombinant Human CD4 Protein at 2 μg/mL (100 μL/well) can bind Ibalizumab-Derived Anti-CD4 Antibody, Human IgG4, the EC50 is 6-20 ng/mL.

• Length:

  603

• Form:

  Lyophilized or frozen liquid

• Buffer:

  PBS, pH 7.4

• Reconstitution:

  See Datasheet

• Molecular Weight:

  67.4 kDa

• Storage Conditions:

  Samples are stable for up to twelve months from date of receipt at -20°C to -80°C. Store it under sterile conditions at -20°C to -80°C. It is recommended that the protein be aliquoted for optimal storage. Avoid repeated freeze-thaw cycles.

• Host or Source:

  HEK 293 cells