In Situ Recovery of hCTLA4Ig in Transgenic Rice Cell Suspension Cultures

초록

A significant challenge in plant-derived protein expression system is to minimize the protein degradation by proteases. hCTLA4Ig, an immunosuppressive agent, was expressed in transgenic rice cell suspension cultures. This fusion protein could be secreted into the culture media by the aid of signal peptide. After secretion of target protein to the extracellular medium, in situ product recovery by using protein A resin was performed to avoid the attack by proteases. Protein A resin which has affinity to IgG portion of target protein was wrapped with a nylon bag and added into the culture medium during production stage. The nylon bag containing protein A resin was collected after 4 hours from the culture medium. The protein A resin capturing hCTLA4Ig was eluted by 0.1 M glycine buffer. In the result, the hCTLA4Ig production was improved by in situ product recovery. In conclusion, it was clear that the effect of protein degradation could be reduced by in situ recovery.