Generation and characterization of monoclonal antibodies against FABP4.

Fatty acid binding protein 4 (FABP4) is a key mediator of intracellular transport and metabolism of fatty acids in adipose tissues. FABP4 binds fatty acids with high affinity and transports them to various compartments in the cell. When in complex with fatty acids, FABP4 interacts with and modulates the activity of two important regulators of metabolism: hormone-sensitive lipase and peroxisome proliferator-activated receptor gamma. Genetic studies in mice clearly indicated that deregulation of FABP4 function may lead to the development of severe diseases such as diabetes II type and atherosclerosis. In this study, we report the production and detailed characterization of monoclonal antibodies (MAbs) against FABP4. Recombinant glutathione S-transferase (GST)-FABP4 or His-FABP4 was expressed in bacteria, affinity purified, and used for immunization of mice, enzyme-linked immunosorbent assay (ELISA) screening, and characterization of selected clones. We have isolated two hybridoma clones that produced antibodies specific for recombinant and native FABP4, as shown by Western blotting and immunoprecipitation. The specificity of generated antibodies was further tested in a cell-based model of adipogenesis. In this analysis, the accumulation of FABP4 during NIH 3T3-L1 differentiation into adipocytes was detected by generated antibodies, which correlates well with previously published data. Taken together, we produced MAbs that will be useful for the scientific community working on fatty acid-binding proteins and lipid metabolism.