Image-based analysis of cell-specific productivity for plant cell suspension cultures

Abstract

More and more plant cell suspension cultures are regarded as an attractive alternative to mammalian cells as host organism for production of complex recombinant proteins. The most important advantages of the production platform are low costs, easy scalability and enhanced safety by complete lack of animal components in the cultivation media. In order to characterize, understand and control such systems accurately, it is important to determine the cell-specific productivity (Qp) of plant cell-based production platforms. Compared to many microbial and mammalian cells the morphology of plant cells is nonhomogeneous and the cells tend to form aggregates, therefore commercial cell counting systems are too unreliable to determine cell numbers in plant suspension cultures. We addressed this limitation by developing a novel cell counting method based on a combination of cell-staining and automated confocal fluorescence microscopy. This method allowed us, for the first time, to determine the cell-specific productivity of transgenic tobacco (Nicotiana tabacum cv. Bright Yellow-2) cell suspension cultures producing the human antibody M12. In the future this method will be a useful tool in the development of optimized plant cell-based production processes

Scaled‐up manufacturing of recombinant antibodies produced by plant cells in a 200‐L orbitally‐shaken disposable bioreactor

“…The MTAD#31.2 cells exhibited a shorter lag phase and therefore faster growth compared to previous reports describing BY-2 growth parameters (Holland et al, 2010;Vasilev et al, 2013), which could be attributed to differences in the medium composition and/or adaption of the cells to the medium. The doubling times of 22.3-23.5 h were similar to those previously described for non-transgenic (Nagata and Nemoto, 1992) and transgenic BY-2 cells (Havenith et al, 2014;Holland et al, 2013). In conclusion, our data prove that the orbitally-shaken SB200-X bioreactor is an efficient and highly scalable platform for the production of biopharmaceutical proteins using tobacco BY-2 cells.…”

Critical Analysis of the Commercial Potential of Plants for the Production of Recombinant Proteins

“…It is rare to find qP values quoted for plant-based systems. For a tobacco cell suspension culture with a maximum yield of 100 mg/L for a full-size antibody, the equivalent qP value is 8.0 pg per cell per day (Havenith et al, 2014). Although this is an order of magnitude lower than the maximum qP values of elite CHO cell lines, it is nevertheless promising because the further optimization of protein productivity in plants appears to be possible by controlling genetic and epigenetic factors, as well as cultivation parameters (Twyman et al, 2013).…”

Putting the Spotlight Back on Plant Suspension Cultures

“…Even without amplification, plant cells are moving toward parity with mammalian cells. For example, cell-specific production rates of 8 pg/cell/day have been reported for the monoclonal antibody M12 produced in tobacco BY-2 cells (Havenith et al, 2014 ) compared to typical production rates of 20–40 pg/cell/day for CHO cells carrying thousands of gene copies, showing that the difference between these systems is less than an order of magnitude.…”