Characterization of a quail suspension cell line for production of a fusogenic oncolytic virus.

The development of efficient processes for the production of oncolytic viruses (OV) plays a crucial role regarding the clinical success of virotherapy. Although many different OV platforms are currently under investigation, manufacturing of such viruses still mainly relies on static adherent cell cultures, which bear many challenges, particularly for fusogenic OVs. Availability of GMP-compliant continuous cell lines is limited, further complicating the development of commercially viable products. BHK21, AGE1. CR and HEK293 cells were previously identified as possible cell substrates for the recombinant vesicular stomatitis virus (rVSV)-based fusogenic OV, rVSV-NDV. Now, another promising cell substrate was identified, the CCX.E10 cell line, developed by Nuvonis Technologies. This suspension cell line is considered non-GMO as no foreign genes or viral sequences were used for its development. The CCX.E10 cells were thus thoroughly investigated as a potential candidate for OV production. Cell growth in the chemically defined medium in suspension resulted in concentrations up to 8.9 × 10 6 cells/mL with a doubling time of 26.6 h in batch mode. Cultivation and production of rVSV-NDV, was demonstrated successfully for various cultivation systems (ambr15, shake flask, stirred tank reactor, and orbitally shaken bioreactor) at vessel scales ranging from 15 mL to 10 L. High infectious virus titers of up to 4.2 × 10 8 TCID 50 /mL were reached in orbitally shaken bioreactors and stirred tank reactors in batch mode, respectively. Our results suggest that CCX.E10 cells are a very promising option for industrial production of OVs, particularly for fusogenic VSV-based constructs.