Establishment and validation of new complementing cells for production of E1-deleted adenovirus vectors in serum-free suspension culture

• Published in: Journal of virological methods 2014-11, Vol.208, p.177-188
• Main Authors: Gilbert, Rénald, Guilbault, Claire, Gagnon, David, Bernier, Alice, Bourget, Lucie, Elahi, Seyyed Mehdy, Kamen, Amine, Massie, Bernard
• Format: Article
• Language: English
• Subjects: Adenovirus vectors; Adenoviruses, Human - genetics; Adenoviruses, Human - growth & development; Biotechnology - methods; Cell Line; Culture Media, Serum-Free; Epithelial Cells - physiology; Genetic Vectors; Humans; Replication-competent adenovirus; Serum-free medium; Suspension culture; T-Lymphocytes, Helper-Inducer - physiology; Technology, Pharmaceutical - methods; Viral Load; Virus Cultivation - methods
• ISSN: 0166-0934; 1879-0984
• DOI: 10.1016/j.jviromet.2014.08.013

•Novel cell lines that produce high-titers of adenovirus vectors have been constructed.•Cell lines grow in suspension culture for scale-up.•Cell lines grow in the absence of serum for regulatory compliance.•Cell lines do not produce replication-competent adenovirus.•Cell lines can produce adenovirus encoding cytotoxic transgene products. E1-deleted adenovirus vectors (AdV) are important gene transfer vehicles for gene therapy and vaccination. Amplification of AdV must take place in cells that express the adenovirus E1A and E1B genes. Sequence homology between AdV and the E1 genes integrated within the complementing cells should be minimal to reduce the odds of generating replication-competent adenovirus (RCA). The present study describes the establishment of AdV complementing cells constructed by stable transfection of the minimal E1A and E1B genes into human lung carcinoma (A549). Because some transgene products can be cytotoxic, the cells were engineered to stably express the repressor of the cumate-switch (CymR) to silence transgene transcription during vector growth. For regulatory compliance and to facilitate the scale-up, the resulting complementing cells (SF-BMAdR) were adapted to serum-free suspension culture. The best clone of SF-BMAdR produced AdV carrying an innocuous transgene to the same level as 293 cells, but titers were better for AdV carrying transgene for a cytotoxic product. Elevated titers were maintained for at least two months in suspension culture in the absence of selective agent and the cells did not produce RCA. Because of their advantageous properties, SF-BMAdR cells should become an important tool for developing large-scale production processes of AdV for research and clinical applications.