Chickens that are genetically engineered to produce human proteins in their eggs may offer an economical method of producing certain types of drugs, research suggests.
The study, which initially focused on producing high quality proteins for use in scientific research, found that the drugs work at least as well as the same proteins produced using the existing methods.
High amounts of the proteins can be recovered from each egg using a simple purification system and there are no adverse effects on the chickens themselves, which lay eggs normally.
Researchers say the results provide solid evidence for the use of chickens as a cheap method of producing high quality medicines for use in research and potentially one day in patients.
Eggs are already used for the cultivation of viruses that are used as vaccines, such as the flu jab. This new approach is different because the therapeutic proteins are encoded in the chicken's DNA and produced as part of the egg white.
The team initially focused on two proteins that are essential for the immune system and have therapeutic potential – a human protein called IFNalpha2a, which has powerful antiviral and anti-cancer effects, and the human and porcine versions of a protein called macrophage-CSF, which is being developed as a therapy that stimulates damaged tissue to repair itself.
Only three eggs were sufficient to produce a clinically relevant dose of the drug. Because chickens can lay up to 300 eggs a year, researchers say their approach may be more economical than other production methods for some important medicines.
Researchers say they have not yet produced drugs for use in patients, but the study offers proof of principle that the system is feasible and can be easily adapted to produce other therapeutic proteins.
Protein-based drugs, which include antibody therapies such as Avastin and Herceptin, are widely used in the treatment of cancer and other diseases.
For some of these proteins, the only way to produce them with sufficient quality involves mammalian cell culture techniques, which are expensive and have low yield. Other methods require complex purification systems and additional processing techniques, which increase costs.
Scientists have already shown that genetically modified goats, rabbits and chickens can be used to produce protein therapies in their milk or eggs. Researchers say their new approach is more efficient, yields better returns and is more profitable than these earlier attempts.
The study was conducted at the Roslin Institute of the University of Edinburgh and Roslin Technologies, a company created to market research at the Roslin Institute.
The research is published in BMC Biotechnology. The Roslin Institute receives strategic funding from the Biotechnology and Biological Sciences Research Council.
Professor Helen Sang of the University of Edinburgh's Roslin Institute said: "We are not yet producing medicines for people, but this study shows that chickens are commercially viable to produce proteins suitable for drug discovery studies and other applications in biotechnology. "
Dr. Lissa Herron, head of Roslin Technologies' Avian Biofarmacy Business Unit, said: "We are excited to develop this technology to its full potential, not only for human therapies in the future but also in research and animal health. "
Dr. Ceri Lyn-Adams, Head of Scientific Strategy, Bioscience for Health at BBSRC, said: "These recent findings provide promising proof of concept for future drug discovery and potential for the development of more economical protein-based drugs" .
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Lissa R. Herron et al., A chicken bioreactor for efficient production of functional cytokines, BMC Biotechnology (2018) DOI: 10.1186 / s12896-018-0495-1