Establishing functional lentiviral vector production in a stirred bioreactor for CAR-T cell therapy

ABSTRACT

As gene delivery tools, lentiviral vectors (LV) have broad applications in chimeric antigen receptor therapy (CAR-T). Large-scale production of functional LV is limited by the adherent, serum-dependent nature of HEK293T cells used in the manufacturing. HEK293T adherent cells were adapted to suspension cells in a serum-free medium to establish large-scale processes for functional LV production in a stirred bioreactor without micro-carriers. The results showed that 293 T suspension was successfully cultivated in F media (293 CD05 medium and SMM293-TII with 1:1 volume ratio), and the cells retained the capacity for LV production. After cultivation in a 5.5 L bioreactor for 4 days, the cells produced 1.5 ± 0.3 × 10⁷ TU/mL raw LV, and the lentiviral transduction efficiency was 48.6 ± 2.8% in T Cells. The yield of LV equaled to the previous shake flask. The critical process steps were completed to enable a large-scale LV production process. Besides, a cryopreservation solution was developed to reduce protein involvement, avoid cell grafting and reduce process cost. The process is cost-effective and easy to scale up production, which is expected to be highly competitive.

ABSTRACT

KEYWORDS:

• Functional
• lentiviral vectors
• HEK293T cells
• stirred bioreactors
• CAR-T cell therapy

Acknowledgements

This study was supported by grants from the National Key R & D Program of China (2017YFD0400304), the Innovative Research Team of Tianjin Municipal Education Commission (TD13-5015), and the Wuhan Science and Technology Plan Project (2019030703011533).

Author contribution

Yong Zhou, Xing-Hua Liao, Tong-Cun Zhang participated in research design; Qu-Lai Tang and Li-Xing Gu performed the experiments and analyzed the data, and were major contributors in writing the manuscript; Yao Xu provided technical guidance and participated in data acquisition and analysis. All the authors read and approved the final version of the manuscript.

Ethics statement

This study was approved by the Ethics Committee of the affiliated Tianyou Hospital of Wuhan University of Science and Technology.

Disclosure of potential conflicts of interest

No potential conflict of interest was reported by the author(s).

Date availability

The data used to support the findings of this study are available from the corresponding author upon request.

Supplementary material

Supplemental data for this article can be accessed here.