CD28 Protein, Human/Cynomolgus (HEK293, Fc)

CD28 Protein, Human/Cynomolgus (HEK293, Fc) is a polypeptide chain with the C-terminal human IgG1 Fc fragment produced in HEK293 cells. CD28, a T cell costimulatory receptor, is a primary target for PD-1-mediated inhibition.

CD28 is the quintessential costimulatory molecule expressed on CD4⁺ and CD8⁺ T cells. During chronic infections and the normal aging process, CD28 expression is lost, compromising the functional activity of T cells. CD28 loss is promoted by replicative stress, particularly in the presence of tumor necrosis factor–α, owing to an inoperative CD28 initiator element. The co-receptor CD28 is strongly preferred over the T cell receptor (TCR) as a target for dephosphorylation by PD-1-recruited Shp2 phosphatase^[1].

1.2 µg/mL (100 µL/well) of immoblized recombinant human CD28-Fc can bind human Biotin-B7-1(CD80)-Fc with a linear range of 0.01-0.5 μg/mL.
2.Immobilized Anti-CD28 mAb at 2 μg/mL (100 μl/well) can bind Human/Cynomolgus CD28-Fc *: Biotinylated by NHS-biotin prior to testing.The ED₅₀ of Human/Cynomolgus CD28-Fc * is 13.97 ng/mL.

Human

HEK293

C-hFc

P10747 (N19-P152)

940  [NCBI]

NKILVKQSPMLVAYDNAVNLSCKYSYNLFSREFRASLHKGLDSAVEVCVVYGNYSQQLQVYSKTGFNCDGKLGNESVTFYLQNLYVNQTDIYFCKIEVMYPPPYLDNEKSNGTIIHVKGKHLCPSPLFPGPSKP

66-70 kDa

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

Lyophilized powder

Lyophilized after extensive dialysis against PBS or 20 mM Tris-HCl, 150 mM NaCl, pH 8.0.

<0.2 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]. Hui E, et al. T cell costimulatory receptor CD28 is a primary target for PD-1-mediated inhibition. Science. 2017 Mar 31;355(6332):1428-1433.  [Content Brief]