Assessment of long-term cryopreservation for production of hCTLA4Ig in transgenic rice cell suspension cultures

Establishment of the Daucus carota SMC-1 Cell Suspension Line for Poliovirus Vaccine Development

The development of virus-free, oral vaccines against poliovirus capable of inducing mucosal protective immunity is needed to safely combat this pathogen. In the present study, a carrot cell line expressing the poliovirus VP2 antigen was established at the level of callus and cell suspensions, exploring the effects of culture media (MS and B5), supplementation with urea, phytoregulators (2,4-D : KIN), and light conditions (continuous light, photoperiod, and total darkness). The best callus growth was obtained on B5 medium supplemented with 2 mg/L of 2,4-D + 2 mg/L kinetin and 0.0136 g/L of urea and in continuous light conditions. Suspension cultures of the SMC-1 line in 250 mL Erlenmeyer flasks had a maximum growth of 16.07 ± 0.03 g/L DW on day 12 with a growth rate of µ=0.3/d and a doubling time of 2.3 days. In a 2 L airlift bioreactor, the biomass yield achieved was 25.6 ± 0.05 g/L DW at day 10 with a growth rate of µ= 0.58/d and doubling time of 1.38 d. Cell growth was 1.5 times higher in bioreactors than in shake flasks, highlighting that both systems resulted in the accumulation of VP2 throughout the time in culture. The maximum VP2 yield in flasks was 387.8 µg/g DW at day 21, while in the reactor it was 550.2 µg/g DW at day 18. In conclusion, bioreactor-based production of the VP2 protein by the SMC-1 suspension cell line offers a higher productivity when compared to flask cultures, offering a key perspective to produce low-cost vaccines against poliomyelitis.

Technoeconomic analysis of semicontinuous bioreactor production of biopharmaceuticals in transgenic rice cell suspension cultures

Biopharmaceutical protein production using transgenic plant cell bioreactor processes offers advantages over microbial and mammalian cell culture platforms in its ability to produce complex biologics with simple chemically defined media and reduced biosafety concerns. A disadvantage of plant cells from a traditional batch bioprocessing perspective is their slow growth rate which has motivated us to develop semicontinuous and/or perfusion processes. Although the economic benefits of plant cell culture bioprocesses are often mentioned in the literature, to our knowledge no rigorous technoeconomic models or analyses have been published. Here we present technoeconomic models in SuperPro Designer® for the large-scale production of recombinant butyrylcholinesterase (BChE), a prophylactic/therapeutic bioscavenger against organophosphate nerve agent poisoning, in inducible transgenic rice cell suspension cultures. The base facility designed to produce 25 kg BChE per year utilizing two-stage semicontinuous bioreactor operation manufactures a single 400 mg dose of BChE for $263. Semicontinuous operation scenarios result in 4-11% reduction over traditional two-stage batch operation scenarios. In addition to providing a simulation tool that will be useful to the plant-made pharmaceutical community, the model also provides a computational framework that can be used for other semicontinuous or batch bioreactor-based processes.