Basic study on mass production of therapeutic proteins for serious disease by genetically engineered rice cell

在基因工程水稻细胞生产治疗性蛋白α_1-抗胰蛋白酶的研究中，获得了以下重要结果：(1)基因工程细胞的生长速度与未转化的水稻细胞的生长速度相同。水稻细胞的比生长速率为0.3d^~(-1)~(-1)，与其他植物细胞的比生长速率相同.(2)氧传递系数K_La为7~8h~(-1)~(-1)，通气量对水稻细胞的生长速率没有影响.(3)在细胞生长期和AAT产生期产生氨.(4)调节培养液和生产介质之间的渗透压有利于AAT的生产。(5)以丙酮酸为替代碳源，AAT的产量提高了两倍。(6)连续搅拌釜式反应器实现了AAT的连续生产。(7)间歇式反应器的菌体密度最高可达14g/g干细胞/L。(8)由于在最佳条件下AAT的最大生产效率为25 mg/g干细胞，在间歇式反应器中可生产至少350 mg/L的AAT，在所采用的表达系统中，可通过缺糖快速诱导重组蛋白。我们的研究有力地表明，利用水稻细胞培养系统可以构建比微生物系统更高效的蛋白质生产系统。我们希望在这项基础性研究的基础上，通过探索过程工程研究，实现利用植物细胞培养的大规模生产系统。

The following significant results were obtained from the research on production of therapeutic protein, α_1-antitrypsin (AAT) by genetically engineered rice cell.(1) Growth rate of genetically engineered cell was the same as that of non-transformed rice cell. Specific growth rate of rice cell, 0.3 d^<-1>, was of the same order of magnitude as those of other plant cells.(2) Oxygen transfer coefficient K_La was 7-8 h^<-1>, and aeration rate did not affect the growth rate of rice cell.(3) Ammonium was produced at cell growth phase and AAT production phase. However, ammonium did not affect the AAT productivity.(4) Adjustment of osmotic pressure between growth medium and production medium has favorable effective for AAT production.(5) AAT productivity was tripled using pyrvic acid as an altemative carbon source.(6) Continuous production was achieved in the continuous stirred tank reactor.(7) Cell density was increased up to 14 g-dry cell/L in the batch-type reactor.(8) Since maximum productivity of AAT at optimal condition was 25 mg/g-dry cell, at least 350 mg/L of AAT can be produced in batch-type reactor.The recombinant proteins can be rapidly induced by sugar depletion in the employed expression system. Our research strongly suggests that protein production system more efficient than microbial system can be constructed by the rice cell culture system. We hope the mass production system using plant cell culture can be achieved by exploring process-engineering research based on this fundamental research.