Biotech Process Sciences, Merck Biopharma, Vevey, Switzerland.
Department of Chemistry and Applied Biosciences, Institute for Chemical and Bioengineering, ETH Zürich, Zürich, Switzerland.
Biotechnol Prog. 2019 May;35(3):e2790. doi: 10.1002/btpr.2790. Epub 2019 Mar 13.
Perfusion cell culture, confined traditionally to the production of fragile molecules, is currently gaining broader attention in the biomanufacturing of therapeutic proteins. The development of these processes is made difficult by the limited availability of appropriate scale-down models. This is due to the continuous operation that requires complex control and cell retention capacity. For example, the determination of an optimal perfusion and bleed rate for continuous cell culture is often performed in scale-down bioreactors and requires a substantial amount of time and effort. To increase the experimental throughput and decrease the required workload, a semi-continuous procedure, referred to as the VCD (viable cell density) approach, has been developed on the basis of shake tubes (ST) and deepwell plates (96-DWP). Its effectiveness has been demonstrated for 12 different CHO-K1-SV cell lines expressing an IgG1. Further, its reliability has been investigated through proper comparisons with perfusion runs in lab-scale bioreactors. It was found that the volumetric productivity and the CSPR (cell specific perfusion rate) determined using the ST and 96-DWP models were successfully (mostly within the experimental error) confirmed in lab-scale bioreactors, which then covered a significant scale-up from the half milliliter to the liter scale. These scale-down models are very useful to design and scale-up optimal bioreactor operating conditions as well as screening for different media and cell lines.
灌注细胞培养传统上仅限于脆弱分子的生产，目前在治疗蛋白的生物制造中受到更广泛的关注。这些工艺的开发受到适当缩小规模模型有限可用性的阻碍。这是由于连续操作需要复杂的控制和细胞保留能力。例如，确定连续细胞培养的最佳灌注和排出率通常在缩小规模的生物反应器中进行，这需要大量的时间和精力。为了提高实验通量并减少所需的工作量，已经基于摇瓶（ST）和深孔板（96-DWP）开发了一种半连续工艺，称为 VCD（活细胞密度）方法。它已在 12 种不同表达 IgG1 的 CHO-K1-SV 细胞系中得到证明。此外，通过与实验室规模生物反应器中的灌注运行进行适当比较，研究了其可靠性。结果发现，使用 ST 和 96-DWP 模型确定的体积生产率和 CSPR（细胞特异性灌注率）在实验室规模生物反应器中成功（大多在实验误差范围内）得到了证实，然后从半毫升到升规模进行了显著放大。这些缩小规模的模型非常有助于设计和放大最佳生物反应器操作条件，以及筛选不同的培养基和细胞系。
