Comparison of Culture Methods for hCTLA4Ig Using Transgenic Rice Cell Suspensions

초록

Various culture methods were compared for the production of hCTLA4Ig (human cytotoxic T-lymphocyte antigen 4-immunoglobulin) using transgenic rice cell suspensions. Production of hCTLA4Ig was induced by sugar starvation using RAmy3D promoter. Sugar-free culture condition and supplementation of additives to induce production were compared. At first, target protein was expressed by simple medium exchange from culture medium into sugar-free medium. Then, concentrated amino acids were supplemented to improve protein production without medium exchange. In addition, supplementation of defined medium with plant-derived peptones (PPs) was investigated. It was found that dramatical enhancement of cell growth and productivity was observed with the supplementation of PPs without medium exchange. To compare the productivities with these culture methods, batch culture condition was used as a control. At day 9 of cultivation, medium was exchanged to sugar-free medium and concentrated amino acids were fed to culture medium, respectively. For the investigation of the effects of PPs, 10 g/L PPs and 10 g/L ultrafiltrated PPs were supplemented with 3% (w/v) sucrose. In conclusion, it was clear that the supplementation of PPs significantly enhanced cell proliferation and hCTLA4Ig production compared to the other methods at early stage.