OPTIMIZATION OF HEK293T SUSPENSION CULTIVATION WITH A DoE-APPROACH IN ambr®15 MICROBIOREACTOR

摘要

Cell and gene therapies present a new treatment paradigm that have the potential to address clinical needs that are unmet by current small molecule and biotherapeutic approaches. Viral vectors such as adenoviruses, adeno-associated viruses and retroviruses are effective delivery systems for genetic material used in cell and gene therapies. Especially lentiviruses are used for example for the transfer of genetic information for novel cellular immunotherapy like CAR-T cell therapy. These novel approaches promise to be a substantial part of next-generation therapies with the potential to cure devastating diseases. HEK293T cells are a workhorse cell line for lentiviral vector production for both cell and gene therapy applications. A significant challenge for the cell and gene therapy industry is to develop a HEK293T suspension cell culture processes that is well characterized and can be scaled-up for production whilst ensuring clinical and commercial success. Ambr® 15 is an automated micro-scale bioreactor system that mimics the features and process control (pH, DO, temperature, stirring rate) provided by much larger scale bioreactors, in a volume of 10 - 15 ml. Parallel processing capability and excellent reproducibility enable rapid, high throughput process improvement and optimization, including DoE studies. High-throughput tools with parallel processing, such as ambr® 15, help to address a major manufacturing bottleneck. They can be used as a scale-down model for process screening, clone selection and effective media optimization in less time with reduced reagents use and labour savings. In the study presented we used ambr® 15 for the optimization of the HEK293T culture in suspension. We identified optimal stirring speed, DO and pH value by performing a DoE approach with the use of MODDE® software for experiment planning. Viable Cell Concentration (VCC), viability and generation time have been monitored and compared to standard shake flask culture. We observed that cultivation of HEK293T cells in the ambr® 15 microbioreactor yields improved cell growth and viability as compared to standard shake flask culture. We identified that pH was the most significant factor -besides stirring speed - which has a lesser significant impact on cell health and growth. By using the MODDE® software we were able to determine an optimal set-point for improved cell growth that can be used for scaling-up studies in stirred tank reactors. This study demonstrates that the ambr® 15 micro bioreactor system in combination with the DoE MODDE® software enables a systematic investigation of critical process parameters and rapid, high throughput process improvement and optimization. The results prove that the transition from shake flask to a scalable stirred bioreactor system can be accomplished in a timely manner. A key next step is to use the identified HEK293T culture conditions to perform a DoE study with the ambr® 15 to optimize viral vector production for cell and gene therapy applications.