Recombinant Human / Cynomolgus / Rhesus macaque CD28 protein(Asn 19 - Pro 152), C-hFc-tagged

• Cat.No.: CD28-3909H
• Product Overview: Recombinant Human / Cynomolgus / Rhesus macaque CD28 protein(Asn 19 - Pro 152)(P10747-1), fused with C-terminal hFc tag, was expressed in HEK293.

Specification

• Species: Human / Cynomolgus / Rhesus macaque
• Source: HEK293
• Tag: Fc
• Protein Length: 1-152 a.a.
• Form: Lyophilized from 0.22 μm filtered solution in Tris with Glycine, Arginine and NaCl, pH7.5 with trehalose as protectant.
• Bio-activity: Immobilized Human / Cynomolgus / Rhesus macaque CD28, Fc Tag (HPLC-verified) at 5 μg/mL (100 μL/well) can bind Biotinylated Human B7-2, Fc,Avitag with a linear range of 0.019-0.625 μg/mL.
• Molecular Mass: The protein has a calculated MW of 41.6 kDa. The protein migrates as 53-66 kDa under reducing (R) condition, and 100-120 kDa under non-reducing (NR) condition (SDS-PAGE) due to glycosylation.
• Endotoxin: Less than 1.0 EU per ug by the LAL method.
• Purity: >95% as determined by SDS-PAGE.
  >90% as determined by SEC-MALS.
• Storage: For long term storage, the product should be stored at lyophilized state at -20°C or lower.
  Please avoid repeated freeze-thaw cycles.
  This product is stable after storage at:
  -20°C to -70°C for 12 months in lyophilized state;
  -70°C for 3 months under sterile conditions after reconstitution.
• Reconstitution: It is recommended that sterile water be added to the vial to prepare a stock solution of 0.2 ug/ul. Centrifuge the vial at 4°C before opening to recover the entire contents.

Gene Information

• Gene Name: CD28 CD28 molecule [ Homo sapiens ]
• Official Symbol: CD28
• Synonyms: CD28; CD28 molecule; CD28 antigen (Tp44); T-cell-specific surface glycoprotein CD28; T cell specific surface glycoprotein; CD28 antigen; Tp44; MGC138290
• Gene ID: 940
• mRNA Refseq: NM_001243077
• Protein Refseq: NP_001230006
• MIM: 186760
• UniProt ID: P10747

Case Study

Case 1: Raychaudhuri K, et al. Front Immunol. 2024

Activating T cells needs the T cell receptor (TCR) to connect with its specific ligand, kicking off a chain of events like phosphorylation of CD3 and TCRζ chains, and activation of kinases like Lck and ZAP70. For a proper immune response, CD28's co-stimulation is crucial, though the exact process hasn't been fully understood. Using TIRF microscopy in Jurkat and mouse T cells, we explored how CD28 influences these initial signaling steps. Our study found that CD28 speeds up the recruitment and activation of ZAP70 at the TCR microclusters and does so by boosting Lck's presence there. This also led to a notable separation between active and inactive forms of Lck in these signaling clusters.

Fig1. Graph shows colocalization of Lck with pTCRζ-Y142 and ZAP70-pY319 and in cells stimulated as indicated.

Fig2. Lysates were resolved by SDS-PAGE and Western blot was performed with indicated antibodies.

Case 2: Wei C, et al. Front Immunol. 2024

We've engineered NECTIN-4 TAC28-T cells, a novel TAC-T variant designed to better tackle solid tumors by incorporating a CD28 segment for enhanced stimulation. In laboratory and animal studies, these NECTIN-4 TAC28-T cells activated effectively when exposed to NECTIN-4 beads, thanks to their CD28 component which boosted activation and proliferation. As a result, NECTIN-4 TAC28-T cells exhibited significantly improved anti-tumor effects compared to the original TAC-T cells, showing great promise in overcoming challenges like poor cell penetration and therapy-associated toxicity in solid tumor treatments.

Fig1. CD27 and CD28 expression.

Fig2. Cytotoxicity of NECTIN-4 TAC28-T and NECTIN-4 TAC28-T cells were assessed.

Application

CD28 is a key player in the immune system, acting as a co-stimulatory molecule that helps activate T cells by interacting with B7 ligands like CD80 and CD86. This interaction is vital for T cell growth and function. Researchers often use recombinant CD28 proteins to understand how these interactions influence immune responses, and they're especially useful for studying ways to adjust immune reactions by targeting the CD28 pathway. In cancer treatment, CD28 is crucial because boosting its interaction with B7 can enhance T cell action against tumors. CD28 is also a component in the design of CAR-T cells, where it boosts their activation and effectiveness against cancer. However, this can lead to the cells’ quick exhaustion due to too much activation. The role of CD28 extends to immune disorders as well; blocking its interaction with B7 can help calm down overactive T cells in conditions like lupus. Recombinant CD28 is instrumental in making specific antibodies for lab tests, helping track its expression in cells. In industry, CD28 is manufactured with high purity for use in research and diagnostics. Therapies targeting CD28, like bispecific antibodies, are being investigated for their potential to fight cancer, showing encouraging early outcomes. Overall, recombinant CD28 is a key asset in both research and treatment, especially for modulating immune responses and enhancing cancer therapies like CAR-T cell therapy.

Fig1. PD-L1/B7-1 cis-interaction in immune checkpoint pathways and T-cell activation. (Marc C Pulanco, 2023)