Hens that lay human proteins in eggs offer future therapeutic hope

Research suggests that chickens genetically engineered to produce human proteins in their eggs may be a cost-effective method of producing certain types of drugs.

The study, which initially aimed to produce high quality protein for scientific research, found that drugs work at least as well as the same proteins produced using existing methods.

Large amounts of protein can be recovered from each egg using a simple purification system and there are no detrimental effects on the chickens themselves, which lay their eggs normally.

The researchers say the results provide strong evidence for the use of chickens as an inexpensive method of producing high quality drugs for research studies and possibly for patients.

Eggs are already used for the culture of viruses used as vaccines, such as the influenza vaccine. This new approach is different because the therapeutic proteins are encoded in the chicken's DNA and produced under the egg white.

The team initially focused on two proteins essential to the immune system and having therapeutic potential: a human protein called IFNalpha2a, which has potent antiviral and anticancer effects, and the human and porcine versions of the immune system. a protein called macrophage-CSF, which is being developed as a therapy that stimulates the repair of damaged tissue.

Three eggs were sufficient to produce a clinically relevant dose of the drug. As hens can lay up to 300 eggs a year, the researchers say their approach could be more cost effective than other production methods for some important drugs.

The researchers claim that they have not yet produced any drugs for the patients but that the study provides proof of principle that the system is workable and that it could easily be adapted to produce other therapeutic proteins.

Protein-based drugs, which include antibody-based therapies, such as Avastin and Herceptin, are widely used to treat cancer and other diseases.

For some of these proteins, the only way to produce them with sufficient quality is to use expensive and low yielding mammalian cell culture techniques. Other methods require complex purification systems and additional processing techniques, which increases costs.

Scientists have already shown that goats, rabbits and genetically modified chickens can be used to produce protein therapies in their milk or eggs. Researchers say their new approach is more efficient, produces better returns and is more cost-effective than previous attempts.

The study was conducted at the Roslin Institute of Edinburgh University and at Roslin Technologies, a company created to commercialize research at the Roslin Institute.

The research is published in BMC Biotechnology. The Roslin Institute receives strategic funding from the Research Council for Biotechnology and Biological Sciences.

Professor Helen Sang, of the Roslin Institute of the University of Edinburgh, said: "We are not yet producing drugs for humans, but this study shows that chickens are commercially viable for the production of proteins suitable for drug discovery studies and other applications in biotechnology. "

Dr. Lissa Herron, Head of Roslin Technologies' Bird Biopharming Business Unit, said, "We are excited to develop this technology to its full potential, not just for future human therapeutics, but also in the areas of research and technology. animal health. "

Ceri Lyn-Adams, Science Strategy Leader, Bioscience for Health at BBSRC, said, "These recent results provide a promising proof of concept for future drug discovery and the potential for more cost-effective protein-based drug development. "

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More information:
Lissa R. Herron et al, A chicken bioreactor for the efficient production of functional cytokines, BMC Biotechnology (2018). DOI: 10.1186 / s12896-018-0495-1