PD1-PDL1 Immune Checkpoint Biochemical Assay

PD-1 is an immune inhibitory receptor that is expressed on activated T and B cells and regulates immune responses to tumor antigens and autoantigens. Engagement of PD-1 on an adjacent cell by either of its ligands, PD-L1 or PD-L2, inhibits TCR signaling and TCR-mediated proliferation, transcriptional activation, and cytokine production. As a result, therapeutic antibodies designed to inhibit the PD-1/PD-L1 interaction are showing promising results in clinical trials for the treatment of a variety of cancers.

Target Overview


To provide a screening assay for identifying small and large molecule PD1 and PDL1 binding interaction blockage inhibitors, with the goal of eventually studying immune responses to aid in the discovery of novel immunotherapies to combat cancer.




Human PD1, human PDL1


PD1: PDCD1, CD279, Programmed cell death protein 1
PDL1: B7 homolog 1, CD274, Programmed cell death 1 ligand 1

Scientific Information

Q15116 (https://www.uniprot.org/uniprotkb/Q15116)
Q9NZQ7 (https://www.uniprot.org/uniprotkb/Q9NZQ7)

Assay Properties


HTRF Assay

Reference Compound IC50s
Compounds IC50 (nM)
PD1/PDL1 Inhibitor 1 (CAS#1675201-83-8) 72.1

Screening Location

Malvern, PA, USA

Further Information

More information can be found on our website Immune Checkpoint Assays

Reference compound inhibition of PD1-PDL1

Reference compound inhibition of PD1-PDL1

Sample data showing reference compound inhibition of PD1-PDL1 binding interaction