CD4 Protein, Human (365a.a, HEK293, His)

CD4 Protein is an integrated membrane glycoprotein that plays various roles in immune responses and defending against internal and external attacks. The alpha-helix structure of CD4 Protein and HIV-1 Vpu can be involved in the binding and degradation of CD4 molecules. CD4 Protein participates in the differentiation/activation, cytokine expression, and cell migration in macrophages or NK cells through a TCR/LCK-independent pathway. CD4 Protein can enhance the host's immune response to viral infections and boost anti-tumor immunity. CD4 Protein, Human (365 a.a, HEK293, His) is a recombinant CD4 protein with a His tag, expressed in HEK293. CD4 Protein, Human (365 a.a, HEK293, His) consists of 365 amino acids, with a molecular weight ranging from 49-58 kDa^[1][2][3].

CD4 Protein is expressed on T helper cells and cytotoxic lymphocytes, interacting with class II major histocompatibility complex (MHC) antigens to mediate cell adhesion^[4].
The expression of CD4 Protein in NK cells can promote the production of cytokines TNF-α and γ-IFN. These cytokines act as important mediators that enhance the host's immune response to viral infections and boost anti-tumor immunity. Additionally, CD4 Protein can mediate the migration of NK cells towards the chemokine IL-16, allowing NK cells to move to the site of acute inflammation, thereby enhancing their innate immune response capability^[2].
CD4 protein can trigger the activation of Src family kinases, ERK1/2, and MAPK-dependent pathways, leading to the differentiation of monocytes into macrophages and resulting in increased expression of TLR8, thereby regulating the innate immune response; it can also induce calcium flux and signal transduction by participating in the ERK/MAPK/NF-κB pathway^[3].
CD4 Protein can be downregulated and degraded by Vpu, and this proteolytic activity requires the phosphorylation of the phosphate receptor sites Ser52 and Ser56, as well as the presence of a second helical structure in the distal cytoplasmic region of Vpu^[1].
CD4 protein is closely related to diseases like tumors and viral infections^[2].

The expression of CD4 Protein in NK cells can promote the production of cytokines TNF - α and γ - IFN and the migration of NK cells towards CD4 specific chemokine IL-16^[2].
CD4 Protein connects with human monocytes, triggers macrophage differentiation, and enhances HIV infection^[4].

CD4 Protein is expressed in a mouse model with endogenous CD4 gene disruption but human CD4 transgenic, thereby restoring helper T cell function^[5].

Measured by the ability of the immobilized protein to support the adhesion of Hela human cervical epithelial carcinoma cells. The ED₅₀ this effect is 1.335-1.418 μg/mL, corresponding to a specific activity is 705.22-749.06 units/mg.

Human

HEK293

C-6*His

P01730 (K26-W390)

920  [NCBI]

KKVVLGKKGDTVELTCTASQKKSIQFHWKNSNQIKILGNQGSFLTKGPSKLNDRADSRRSLWDQGNFPLIIKNLKIEDSDTYICEVEDQKEEVQLLVFGLTANSDTHLLQGQSLTLTLESPPGSSPSVQCRSPRGKNIQGGKTLSVSQLELQDSGTWTCTVLQNQKKVEFKIDIVVLAFQKASSIVYKKEGEQVEFSFPLAFTVEKLTGSGELWWQAERASSSKSWITFDLKNKEVSVKRVTQDPKLQMGKKLPLHLTLPQALPQYAGSGNLTLALEAKTGKLHQEVNLVVMRATQLQKNLTCEVWGPTSPKLMLSLKLENKEAKVSKREKAVWVLNPEAGMWQCLLSDSGQVLLESNIKVLPTW

49-58 kDa

• 
  Greater than 95% as determined by reducing SDS-PAGE.

Lyophilized powder.

Lyophilized from a 0.2 μm filtered solution of PBS, pH 7.4 or 20 mM PB, 150 mM NaCl, pH 7.4.

<1 EU/μg, determined by LAL method.

It is not recommended to reconstitute to a concentration less than 100 μg/mL in ddH₂O. For long term storage it is recommended to add a carrier protein (0.1% BSA, 5% HSA, 10% FBS or 5% Trehalose).

Stored at -20°C for 2 years. After reconstitution, it is stable at 4°C for 1 week or -20°C for longer (with carrier protein). It is recommended to freeze aliquots at -20°C or -80°C for extended storage.

Room temperature in continental US;may vary elsewhere.

• [1]. Tiganos E, et al. Putative alpha-helical structures in the human immunodeficiency virus type 1 Vpu protein and CD4 are involved in binding and degradation of the CD4 molecule. J Virol. 1997 Jun;71(6):4452-60.  [Content Brief]

  [2]. Bernstein HB, et al. CD4 expression on activated NK cells: ligation of CD4 induces cytokine expression and cell migration. J Immunol. 2006 Sep 15;177(6):3669-76.  [Content Brief]

  [3]. Zhen A, et al. CD4 ligation on human blood monocytes triggers macrophage differentiation and enhances HIV infection. J Virol. 2014 Sep 1;88(17):9934-46.  [Content Brief]

  [4]. Doyle C, et al. Interaction between CD4 and class II MHC molecules mediates cell adhesion. Nature. 1987 Nov 19-25;330(6145):256-9.  [Content Brief]

  [5]. Killeen N, et al. Regulated expression of human CD4 rescues helper T cell development in mice lacking expression of endogenous CD4. EMBO J. 1993 Apr;12(4):1547-53.  [Content Brief]