Effects of osmotic pressure on hCTLA4-Ig production in transgenic rice cell suspension cultures

초록

Immunosuppressive agent, human cytotoxic T lymphocyte antigen 4 (hCTLA4), is used for the prevention of graft rejection and treatment of autoimmune diseases. hCTLA4-Ig, a CTLA4-immunoglobulin fusion protein, was produced and secreted from transgenic rice cell suspension cultures using a rice a-amylase (RAmy3D) expression system. In this system, hCTLA4-Ig expression was regulated metabolically by sugar starvation. For the purpose of improving hCTLA4-Ig yield, the effects of osmotic pressure was investigated in suspension cultures of transgenic rice cells. The highest production yield was achieved at 80 mM sorbitol (174 mOsm·㎏-1H2O). By adjusting the osmotic pressure of induction medium, we found that the production of target protein increased 1.7-fold, compared with that in control medium without carbon source.