Validation of 57 Tag-lite ligand binding assay starter packs. Correlation of agonist and antagonist Ki obtained with Tag-lite and radioactive ligand binding assays

Ligand binding assays which investigate the first step of the drug receptor interaction remain a method of choice when investigating drug effects. Despite the constraints associated with the use of a radioactive ligand (including delivery, disposal of radioactive material, half-life and radiolysis of compounds inducing short shelf-life of the ligand) radioactive methods remain the gold standard in receptor ligand binding assays. Nevertheless, homogeneous and non-radioactive alternatives are being investigated to provide HTS assays. An additional incentive is that some ligands have induced a high non-specific binding (NSB) making radioligand assays time-consuming to develop (e.g. chemokine assays). Tag-lite is a new homogeneous and non-radioactive cell-based platform developed by Cisbio Bioassays to address ligand receptor interaction. All these assays are available under a ready-to-use starter pack format containing the fluorescent ligand and the pre-labeled frozen cells. To date, 57 fully validated GPCR packs are available.