2. Production Systems
Bacteria
Yeast
Plant tissue culture
Animal cells (CHO)
Transgenic animals
Insect
Expression of recombinant proteins
Adapted from www.cloud-clone.com/
3. Bacteria
For e.g, Escherichia coli (Gram negative bacteria) strains in the production of recombinant Insulin
Pros
Well characterized system
High yield and cost effective
Well-established fermentation procedures
Cons
Poor secretion
Inclusion bodies: costly to renature inactive product
Others: Accumulation of toxic metabolites, Proteolysis
4. Fungal
For e.g, Saccharomyces cerevisiae and Pichia pastoris in the production of recombinant Insulin
Pros
Post translational modifications: Disulphide bonds
Secretion possible
Cons
Safety: use of Methanol
Glycosylation of non-glycosylated proteins (Half-life and Immunogenicity)
5. Insect
E.g. Trichoplusiani, Hi 5 insect cell line used to produce Cervarix HPV vaccine
Baculovirus-insect cell system (BEVS)
Pros
Target gene transfer – high efficiency
High recombinant protein yields
Cons
Complex, defined media; costly
Construction & amplification of viral stocks – 2-3 weeks
Clone into bacteria
transfer vector
Recombinant
baculovirus generation
Small scale
expression test
Optimization and large
scale expression
6. Plant Tissue Culture
E.g. human serum albumin, derived from Nicotiana
tabacum suspensions culture
Plant-cell based expression system
Adapted from Singhabahu et al., 2016
Pros
High efficiency expression technique and scalable
Intrinsically safe – neither harbor human pathogens
nor produce endotoxins
Cons
Reduction in genetic diversity
Disease infection may continue through generation
7. Animal cell culture
Animal cell cultures are the recent achievements and perspectives in the production of biopharmaceuticals
Efficacy of several humanized monoclonal antibodies that are used for therapeutic use
E.g. Trastuzumab, Bevacizumab, Alemtuzumab, Belimumab
Production
Fused cells, myeloma cells, B cells.
HAT (Hypozanthine Aminopterine thymidine) medium
Blocks the De Novo pathway of production of nucleotide bases
Only the Hybrid cells are capable of producing HGPRT
(Hypoxanthine-Guanine Phospho Ribosyl Transferase)
HGPRT- Induction of the production of Purines and Pyrimidines by Salvage pathway
Hybrid cells can survive the HAT medium
8. Animal cell culture
Pros
Physiological & Physio-chemical environment is controlled
Easy maintenance of Cell Homogenecity
Long term storage using liquid Nitrogen and DMSO
Usage of animals for scientific study can be reduced
Cons
Sterility and aseptic maintenance
Capital investment is high and effective maintenance required
High chance of genomic variation due to rapid growth
10. Steps to making recombinant biological products
1. Develop host
2. Establish cell bank
3. Protein production system
4. Purification
5. Analysis
6. Formulation
12. Recombinant Human Insulin Production
Working Cell Bank
Vial Thaw
Pre-culture (n 1)
(shake flask)
Seed Culture (n 1)
(Fermentor)
Main Fermentation
1. Cell Growth
2. Induction and Protein
Expression
Harvest (Centrifugation)
Clarification
(Depth filtration)
Cation Exchange
Chromatography
Anion Exchange
Chromatography
Ultrafiltration /
Diafiltration
(Buffer Exchange)
Drug Substance
Formulation
Bulk Drug Substorage
Seed train
Fermentation
Primary
Recovery
Upstream Process Downstream Process
Inoculum
expansion
13. General considerations for Recombinant Protein
Production
Adapted from Mudassar Ahmad et al, 2014P.pastoris
14. Conclusion
Bacteria: first choice for protein production; fact growth and simple culture procedures
Yeast: Post-translational modifications and secretion of proteins
Insect: High recombinant protein yield with high efficient target gene transfer
Plant: High efficiently expression system for ease of production, produce safe edible vaccines
Animal Cell Cultures are the recent achievement for the production of Biologics and Biosimilars
Efficacy of several humanized monoclonal antibodies that are required for therapeutic use
15. Jozala, A. F., et al. (2016). Biopharmaceuticals from microorganisms: from production to purification. Brazilian Journal of
Microbiology. 47S:51–63
Baeshen, N. A., et al. (2014). Cell factories for insulin production. Microbial cell factories.13:141
Krammer, F. (2010). Grabherr, R. Alternative influenza vaccines made by insect cells. Trends in molecular medicine. 16: 313-320
Weber, W., & Fussenegger, M. (2009). Insect Cell-Based Recombinant Protein Production. Principles and Practice. 263–277
Singhabahu, S., Hefferon, K., & Makhzoum, A. (2016). Plant Molecular Pharming. In: Jha S. (eds). Transgenesis and Secondary
Metabolism. 1–26
https://www.easybiologyclass.com/advantages-and-disadvantages-of-animal-cell-culture-short-lecture-notes/
https://www.abcam.com/protocols/a-comparison-between-polyclonal-and-monoclonal
https://www.google.com/search?biw=1366&bih=606&tbm=isch&sa=1&ei=TxCmXJuIC9T-9QO-
uLmYBA&q=animal+tissue+culture&oq=animal+tissue+culture&gs_l=img.3..35i39j0l9.44080.45251..46750...0.0..
0.124.1551.9j7......1....1..gws-wiz-img.aZngU49oszY#imgrc=x7LroZ4NKeWa-M:
References
Editor's Notes
Recent years, insect cells have been widely used for biologically active recombinant proteins production. An example is the use of Hi5 insect cell line to produce HPV vaccine by Cervarix.
Baculovirus-insect cell system is the most widely used insect cell-based expression system.
In practice, the gene(s) of interest is first cloned into Baculovirus donor plasmid. In the following step, the constructed target gene-Baculovirus donor vector transform a special E.coli strain for generation of recombinant bacmid, which is then extracted and used for transfection of Hi5 insect cell to produce the first batch of recombinant baculovirus. Next, a small scale expression test is carried out. Once the cells are inspected to display signs of infection, the recombinant baculovirus is then harvested and amplified to produce high titer stock for protein expression and lastly purification to obtain purified recombinant protein.
So, this system is advantages in target gene transfer with very high efficiency and high recombinant protein yield.
However, the drawbacks of this system are it requires expensive complex media and the construction and amplification of viral stocks is necessary and takes up to 2-3 weeks.
http://www.oppf.rc-harwell.ac.uk/OPPF/courses/oppf2015/talks/OPPFCourse2015__Arnuad_Poterszman.pdf
https://www.profacgen.com/recombinant-protein-expression-in-insect-cells.htm
https://biotop.boku.ac.at/Projects/2015/Grabherr2015c.html
Next, Plants have also been increasingly researched as an alternative recombinant protein expression system.
For example, human serum albumin derived from Nicotiana tabacum suspensions culture initiated from transgenic plant.
In plant-cell based expression system, the candidate antigen can be expressed by stable integration, first method is by using natural plant pathogens like Agrobacterium tumefaciens as vector mediated carrier system for stable integration of antigenic DNA into plant nucleus at random loci. Another one is using ‘gene guns’ to integrate candidate gene into specific site in plant circular chloroplast DNA (cpDNA).
For transient expression, candidate gene can be mediated by positive sense, single stranded plant RNA viruses (Tobacco etch virus, Cauliflower mosaic virus, Tobacco mosaic virus etc). In this method, the engineered viral genome will not become integrated into host plant genome and are expressed by infected generation only. Another is demonstrated by infiltration (agroinfiltration technique) of suspensions of Agrobacterium tumefaciens which harbouring a binary vector into leaf interstitial spaces.
These expressions result in formation of stable transgenic plant, where the antigen can be extracted or directly used as edible plants.
This system is benefited with high efficiency expression technique and easily scalable to production, and plant cells are intrinsically safe.
The drawbacks are reduction in genetic diversity and may be disease infection throughout generation.
__________
E.g. Eleyso (taliglucerase alpha), an enzyme with a human compatible glycan profile, produced by genetically modified carrot plant root cells.
which is used in enzyme replacement therapy (ERT) to treat Gaucher’s disease, has been produced by Protalix Biotherapeutics.
Stable integration: This method is benefited by the inherent capability of plant pathogens to infect and transfer its virulent genes to the nucleus of host cell. The main advantages of this method are ease of production, cost effectiveness, ability to introduce large DNA segments with higher efficiencies into the plant genome etc.