Immune checkpoint proteins are believed to be the primary regulators that control the immune system's defense against threats and sustain tolerance. Co-inhibitory receptors (CTLA-4, PD-1, TIGIT, LAG-3) that limit T-cell activity and co-stimulatory receptors (GITR, 4-1BB, OX40, CD40) that tend to activate T cells are components of the conventional immune checkpoint.
Patients with metastatic solid tumors had significantly higher survival rates when their co-inhibitory receptors, CTLA-4 (cytotoxic T-lymphocyte antigen 4) and PD-1 (programmed cell death protein 1), were suppressed. Therefore, a major approach in cancer treatment is using antibody drugs targeting immune checkpoints for tumors, cancer, and other diseases.
Pathways of Immune Checkpoint
Image Credit: ACROBiosystems
Product Features
- High purity confirmed using MALS or HPLC
- High bioactivity confirmed by FACS, ELISA, SPR, and other methods
- Strict quality control testing ensures high batch-to-batch consistency
Main Applications
- Antibody binding assay
- Antibody affinity assay
- Neutralizing antibody binding assay
- Cell-based assay
TNFSF proteins. Image Credit: ACROBiosystems
CD47 proteins. Image Credit: ACROBiosystems
CTLA-4 homodimer proteins. Image Credit: ACROBiosystems
B7-CD28 family proteins. Image Credit: ACROBiosystems
Key Features
Authentic Structure Verified by SEC-MALS
The purity of Human CD27 Ligand, His, Flag Tag (active trimer) (MALS verified) (Cat. No. CDL-H52Da) was more than 95% in HP-SEC, and around 55-70 kDa verified by SEC-MALS. Image Credit: ACROBiosystems
High Batch-to-Batch Consistency
Consistency in purity and bioactivity is essential for recombinant proteins. To determine its purity and bioactivity, every protein must successfully complete a series of assessments.
Biotinylated Human PD-1 / PDCD1 Protein, Avitag™, His Tag (recommended for biopanning) (MALS verified) (Cat. No. PD1-H82E4). Image Credit: ACROBiosystems
Application 1: Development and Screening of Antibody Drugs
Antibody Binding Assay
Immobilized Human PD-1, His Tag (Cat. No. PD1-H5221) at 2 μg/mL (100 μL/well) can bind Nivolumab with a linear range of 0.1-3 ng/mL (Routinely tested). Image Credit: ACROBiosystems
Serial dilutions of nivolumab were added into Human PD-1, Fc Tag, low endotoxin (Cat. No. PD1-H5257): Biotinylated Human PD-L1, Fc, Avitag, His Tag (Cat. No. PD1-H82F3) binding reactions. The half maximal inhibitory concentration (IC50) is 0.5381 μg/mL (Routinely tested). Image Credit: ACROBiosystems
ACROBiosystems has also created inhibitor screening assay kits for PD1: PD-L1 (Cat. No. EP-101) and CD47: SIRP alpha (Cat. No. EP-102) that enable high-throughput screening of neutralizing antibodies or small compounds.
Antibody Drug Affinity Assay
Anti-LAG-3 MAb (Human IgG1) captured on CM5 chip via Anti-Human IgG Fc antibodies surface, can bind Human LAG-3, His Tag (Cat. No. LA3-H5222) with an affinity constant of 4.57 nM as determined in a SPR assay (Biacore T200) (Routinely tested). Image Credit: ACROBiosystems
Loaded Anti-LAG-3 MAb (Human IgG1) on AHC Biosensor, can bind Human LAG-3, His Tag (Cat. No. LA3-H5222) with an affinity constant of 7.47 nM as determined in BLI assay (ForteBio Octet Red96e) (Routinely tested). Image Credit: ACROBiosystems
Neutralizing Antibody Binding Assay
Serial dilutions of Human TIGIT Neutralizing antibody were added into Human TIGIT, Fc Tag (Cat. No. TIT-H5254): Biotinylated Human CD155, Fc, Avitag (Cat. No. CD5-H82F6) binding reactions. The half maximal inhibitory concentration (IC50) is 0.55834 μg/mL (Routinely tested). Image Credit: ACROBiosystems
FACS analysis shows that the binding of Human CD47 to ACHN expressing SIRP-a was inhibited by increasing concentration of neutralizing SIRP-a antibody. The concentration of Human CD47 used is 20 μg/mL. IC50 = 9.334 μg/mL. Image Credit: ACROBiosystems
Cell-Based Assay
Human 4-1BB Ligand (71-254), Fc Tag, active trimer (Cat. No. 41L-H5265) induce IL-8 secretion in HT1080 human CD137 cell line. The EC50 for this effect is 0.079 μg/mL (Routinely tested). Image Credit: ACROBiosystems
Pharmacokinetics (PK) Analysis
Immobilized Human CTLA-4, His Tag, active dimer (Cat. No. CT4-H52H9) at 2 μg/mL, add increasing concentrations of CTLA-4 x OX40 Bispecific Antibody in 50% Human serum and then add Biotinylated Human OX40, Avitag, His Tag(Cat. No. TN4-H82E4) at 1 μg/mL. Detection was performed using HRP-conjugated streptavidin with sensitivity of 4 ng/mL (Intact assay, Routinely tested). Image Credit: ACROBiosystems