Monoclonal antibodies as surrogate receptors in a high throughput screen for compounds that enhance insulin sensitivity

Monoclonal antibodies (MoAbs) were made to a known insulin sensitivity enhancer (ISE) compound, CS-045. The MoAbs were characterized with respect to binding other known thiazolidinedione ISE compounds using a CS-045 labeled with b-phycoerythrin in a competitive particle concentration fluorescence immunoassay (PCFIA). By comparing the rank order of IC50 values for each compound to its respective potency as an ISE, one MoAb (13E3) was selected for further characterization. This MoAb was also used as a surrogate receptor in a high throughput screen to identify novel compounds that compete for binding to CS-045. Some of the hits were found to have efficacy in reducing blood glucose. Subsequently, another group reported that several compounds with the core thiazolidinedione structure of the ISE compounds bound with high affinity to peroxisome proliferator-activating receptors (PPAR). Therefore, we used the MoAb assay to test these and other compounds that are known to bind to PPARy and noted crossreactivity with some of the compounds.