Jänne J, Hyttinen J M, Peura T, Tolvanen M, Alhonen L, Halmekytö M
Department of Biochemistry & Biotechnology, University of Kuopio, Finland.
Ann Med. 1992 Aug;24(4):273-80. doi: 10.3109/07853899209149954.
Many human therapeutic proteins are currently produced with the aid of recombinant DNA technology in microbial bioreactors and a few also in large-scale animal cell cultures. Although extremely cost-efficient, the microbial production system has many inherent limitations. Micro-organisms, such as bacteria, can read the universal genetic code and hence produce human proteins with correct amino acid sequence, but cannot carry out post-translational modifications, such as glycosylation, or fold the newly synthesized protein properly to ultimately generate a biologically active entity. Moreover, even though the production of the proteins as such is inexpensive, the downstream processing of the final product may be extremely difficult and costly. Many of these disadvantages, especially the lack of post-translational modifications, can be overcome by employing large-scale animal cell cultures for the production of proteins of pharmaceutical interest. However, due to the long generation time and the requirement for rich culture media, the use of animal cell bioreactors is unacceptably expensive. With the advent of transgenic technology, the production of human pharmaceuticals in large transgenic animals has become more and more attractive. The use of targeted gene transfer, the expression of the transgene of interest can be directed to occur in the mammary gland of large farm animals, such as pigs, sheep, goats or dairy cattle, and hence the transgene product is ultimately being secreted into the milk. Although not yet in commercial use, the last few years have witnessed a remarkable progress in this area and proved the feasibility of the use of 'molecular farming' in high-quantity, low-cost production of valuable therapeutic or industrial proteins. While reviewing the progress of the field over the past few years, we discuss in somewhat greater detail aspects connected with the use of dairy cattle as bioproducers of human therapeutic proteins.
目前，许多人类治疗性蛋白质是借助重组DNA技术在微生物生物反应器中生产的，少数也在大规模动物细胞培养物中生产。尽管微生物生产系统极具成本效益，但也有许多固有的局限性。微生物，如细菌，能够解读通用遗传密码，因此能产生具有正确氨基酸序列的人类蛋白质，但无法进行翻译后修饰，如糖基化，也不能正确折叠新合成的蛋白质以最终生成具有生物活性的实体。此外，尽管蛋白质本身的生产成本低廉，但最终产品的下游加工可能极其困难且成本高昂。通过采用大规模动物细胞培养来生产具有药用价值的蛋白质，可以克服许多这些缺点，尤其是缺乏翻译后修饰的问题。然而，由于动物细胞的生长周期长且需要丰富的培养基，使用动物细胞生物反应器的成本高得令人难以接受。随着转基因技术的出现，利用大型转基因动物生产人类药物变得越来越有吸引力。利用靶向基因转移，可以使感兴趣的转基因在大型农场动物（如猪、绵羊、山羊或奶牛）的乳腺中表达，从而使转基因产物最终分泌到乳汁中。尽管尚未投入商业使用，但在过去几年中该领域取得了显著进展，并证明了利用“分子农场”大量、低成本生产有价值的治疗性或工业用蛋白质的可行性。在回顾该领域过去几年的进展时，我们将更详细地讨论与利用奶牛作为人类治疗性蛋白质生物生产器相关的方面。
