Plant Biotechnology meets Immunology : plant-based expression of immunologically relevant proteins
Wilbers, R.H.P. - \ 2015
Wageningen University. Promotor(en): Jaap Bakker, co-promotor(en): Arjen Schots; Geert Smant. - Wageningen : Wageningen University - ISBN 9789462574335 - 229
plantenbiotechnologie - immunologie - planten - eiwitten - farmaceutische eiwitten - interleukine 10 - ontstekingsremmers - biologische activiteit - cytokinen - genexpressie - transforming growth factor - wormen - recombinant eiwitten - glycoproteïnen - plant biotechnology - immunology - plants - proteins - pharmaceutical proteins - interleukin 10 - antiinflammatory agents - biological activity - cytokines - gene expression - helminths - recombinant proteins - glycoproteins
The incidence of inflammatory disorders in industrialized countries has dramatically increased over the last decennia, which is believed to result from a change in life-style. Treatment of these inflammatory disorders relies on the intervention in immune responses thereby restoring homeostasis. For now, many inflammatory disorders are treated with broad-acting immunosuppressive drugs or monoclonal antibodies that specifically target pro-inflammatory molecules of the immune system. An alternative therapeutic approach would be to use immunomodulatory proteins that are naturally involved in re-establishing immune homeostasis. This thesis describes the plant-based expression of a variety of immunomodulatory cytokines that may be used as biopharmaceutical proteins in the future. Furthermore, this thesis contains a pioneering chapter on the plant-based expression of immunomodulatory helminth-secreted glycoproteins.
In Chapter 2 we describe the plant-based expression of the immune-regulatory cytokine human transforming growth factor β1 (TGF-β1). By co-expressing human furin with latent TGF-β1 we were able to engineer the post-translational proteolytic processing of TGF-β1, which enabled the production of biologically active TGF-β1. In Chapter 3 we reveal that aggregation is a major production bottleneck for the anti-inflammatory cytokine interleukin-10 (IL-10). By protein engineering we were able to prevent aggregation and created a biologically active fusion protein of IL-10. In Chapter 4 we express biologically active IL-22 in plants. We reveal that, in contrast to current literature, its activity is independent of the presence of N-glycans or their composition. This chapter further reveals that plants offer a powerful tool to allow investigation into the role of N-glycans in protein folding and biological activity of glycoproteins. In Chapter 5 we further explore the potential of glyco-engineering in plants by engineering helminth-like N-glycans. We produce large quantities of two major egg antigens from Schistosoma mansoni and successfully engineer Lewis X, LDN and LDNF N-glycan structures. These plant biotechnological research lines are a showcase for the potential of engineering proteins as well as post-translational modifications in plants with special emphasis on N-glycan engineering. Altogether, the results presented in the first four chapters reveal the remarkable flexibility of plants as a production platform for recombinant proteins. It showcases the potential of engineering proteins as well as post-translational modifications in plants, but it especially highlights the engineering of tailor made N-glycans in plants. This, combined with the speed of transient expression by means of agroinfiltration, makes transient expression in Nicotiana benthamiana a powerful tool to study the role of N-glycans on glycoprotein function.
In parallel to these plant biotechnological research lines, we also developed an in vitro model system based on mouse bone marrow-derived cells to study immunological responses. We used this model to obtain clues on why IL-10 therapy has not been as successful as previously anticipated. In Chapter 6 we have set-up biological activity assays based on bone marrow-derived cells and reveal that IL-10 activity is dependent on both IL-10R1 and IL-10R2, but not IL-10R2-associated signalling via Tyk2. We also show that interactions between IL-10R1 and IL-10R2 (both intracellular and extracellular) reduce cellular binding of IL-10, but are crucial to initiate IL-10 mediated signalling. Furthermore, we observed that macrophages and dendritic cells respond differently to IL-10. This was further investigated in Chapter 7 where we reveal that GM-CSF (the cytokine used to differentiate dendritic cells) is responsible for negatively regulating early IL-10-mediated responses. Strikingly, GM-CSF does not strongly affect the IL-10-induced activation of the transcription factor STAT3. Instead, GM-CSF induces strong constitutive phosphorylation of GSK-3β, a signalling component downstream of the PI3K/Akt pathway. These immunological chapters give novel insights on the mechanism of initiating IL-10-induced signalling and on the possible integration of signal transduction pathways elicited by different cytokines. Ultimately this knowledge could provide us with new therapeutic strategies to treat inflammatory disorders.
Scaled-up manufacturing of recombinant antibodies produced by plant cells in a 200-L orbitally-shaken disposable bioreactor
Raven, N. ; Rasche, F. ; Kuehn, C. ; Anderlei, T. ; Klöckner, W. ; Schuster, F. ; Henquet, M.G.L. ; Bosch, H.J. ; Büchs, J. ; Fischer, R. ; Schillberg, S. - \ 2015
Biotechnology and Bioengineering 112 (2015)2. - ISSN 0006-3592 - p. 308 - 321.
expanded-bed adsorption - enzyme replacement therapy - high-yield production - full-size antibody - pharmaceutical proteins - monoclonal-antibody - suspension-cultures - foreign proteins - cho-cells - purification
Tobacco BY-2 cells have emerged as a promising platform for the manufacture of biopharmaceutical proteins, offering efficient protein secretion, favourable growth characteristics and cultivation in containment under a controlled environment. The cultivation of BY-2 cells in disposable bioreactors is a useful alternative to conventional stainless steel stirred-tank reactors, and orbitally-shaken bioreactors could provide further advantages such as simple bag geometry, scalability and predictable process settings. We carried out a scale-up study, using a 200-L orbitally-shaken bioreactor holding disposable bags, and BY-2 cells producing the human monoclonal antibody M12. We found that cell growth and recombinant protein accumulation were comparable to standard shake flask cultivation, despite a 200-fold difference in cultivation volume. Final cell fresh weights of 300-387¿g/L and M12 yields of ~20¿mg/L were achieved with both cultivation methods. Furthermore, we established an efficient downstream process for the recovery of M12 from the culture broth. The viscous spent medium prevented clarification using filtration devices, but we used expanded bed adsorption (EBA) chromatography with SP Sepharose as an alternative for the efficient capture of the M12 antibody. EBA was introduced as an initial purification step prior to protein A affinity chromatography, resulting in an overall M12 recovery of 75-85% and a purity of >95%. Our results demonstrate the suitability of orbitally-shaken bioreactors for the scaled-up cultivation of plant cell suspension cultures and provide a strategy for the efficient purification of antibodies from the BY-2 culture medium.