The OX40[Biotinylated]:OX40L Inhibitor Screening Assay Kit is designed for screening and profiling inhibitors of OX40:OX40L interaction. The key to this kit is the high sensitivity of detection of biotinlabeled OX40 by streptavidin-HRP. Only a few simple steps on a microtiter plate are required for the assay. First, OX40L is coated on a 96-well plate. Next, OX40-biotin is incubated with OX40L on the plate. Finally, the plate is treated with streptavidin-HRP followed by addition of an HRP substrate to produce chemiluminescence, which can then be measured using a chemiluminescence reader.