The CD40:CD40L[Biotinylated] Inhibitor Screening Assay Kit is designed for screening and profiling inhibitors of CD40:CD40L signaling. This kit comes in a convenient 96-well format, with biotin-labeled CD40, purified CD40L, streptavidin-labeled HRP, and assay buffer for 100 binding reactions. The key to this kit is the high sensitivity of detection of biotin-labeled CD40 by streptavidin-HRP. Only a few simple steps on a microtiter plate are required for the assay. First, CD40L is coated on a 96-well plate. Next, CD40 is incubated with CD40L on the plate. Finally, the plate is treated with streptavidin-HRP followed by addition of an HRP substrate to produce chemiluminescence, which can be measured using a chemiluminescence reader.