Discovery of cytokine mimics using cell-based systems.

The successful cloning and subsequent clinical application of recombinant cytokines and/or growth factors has generated a number of important therapeutics. In contrast to the G-protein-coupled receptors, identification of small-molecule agonists of the cytokine and/or growth factor receptor family has proved difficult. The first small peptides and non-peptidic small-molecule agonists for several receptors have recently been reported. The initial identification and/or crucial characterization of these molecules as true mimics was dependent on the use of cell-based functional assays. This article will review recent cell-based assay technologies that are suitable for HTS and that are being applied to the discovery of novel cytokine and growth factor mimics.