Immune Checkpoint Assays

Screen your immune checkpoint blockers

The HTRF immune checkpoint binding assays are designed to measure the interaction between immune checkpoint proteins.

The best TR FRET assays on the market

  • All components included: validated proteins, detection antibodies & buffers
  • Screen human or mouse blocker antibodies
  • Screen small molecules
  • From 96 to 1536 format

How it works

The immune checkpoint binding assay is designed to measure the interaction between a Tagged-checkpoint protein (Tag1-protein) and its tagged-ligand (Tag2-ligand).

Utilizing HTRF (Homogeneous Time-resolved Fluorescence) technology, the interaction between the Tag1-protein and Tag2-ligand is detected by using anti-Tag1-Cryptate (HTRF donor) and anti-Tag2-XL665 (HTRF acceptor). When the donor and acceptor antibodies are brought into close proximity due to protein-ligand binding, excitation of the donor antibody triggers fluorescent resonance energy transfer (FRET) towards the acceptor antibody, which in turn emits specifically at 665 nm. This specific signal is directly proportional to the protein/ligand interaction. Thus, compound or antibody blocking protein/ligand interaction will cause a reduction in HTRF signal.

PD1/PD-L1: Inhibitory effect of small molecules and antibodies

The inhibitory effects of small molecules, human and mouse blocking antibodies of PD1 and PD-L, were tested at 5 nM PD-L1 and 50 nM PD1. An assay window around 10 was obtained.

ProductCat. No.BindingHuman AbMouse AbSmall molecule



CTL4/B7-1 (CD80)

CTL4/B7-2 (CD86)



Related to:
Brands: Cisbio Bioassays (HTRF®)
News: Immune Checkpoints