Turning chickens into pharmaceutical bioreactors

31-01-2007 | |

Researchers have managed to successfully express human interferon alpha-2a in the egg whites of eggs laid by their flock of genetically modified hens.

This is the third therapeutic protein that researchers at the Roslin Institute (in collaboration with Oxford BioMedica and Viragen) have succeeded in producing in the transgenic eggs, already having reported positive results for interferon beta 1-a and a monoclonal antibody (miR-24).
The results mark another step in the group’s proof-of-principle study with the aim of establishing the process as an alternative to current costly bio-manufacturing processes.
“The project is designed to develop the chicken into a pharmaceutical bioreactor, one that can meet the growing need for protein-based human therapeutics,” said a representative of Oxford BioMedica.
Alpha interferon is produced by the human immune system and is crucial in disease resistance. Interferon alpha-2a, which the researchers successfully produced, is the active ingredient in Hoffman-La Roche‘s drug Roferon A (interferon alpha-2a, recombinant), used for the treatment of chronic hepatitis C, hairy cell leukaemia, and AIDS-related Kaposi’s sarcoma.
Only a few weeks ago the collaborative group announced that they had successfully managed to breed five generations of transgenic hens, maintaining expression of therapeutic proteins in the egg whites through the generations. This was a significant step in taking the field closer to the possibility of transgenic flocks that could be used as natural bio-manufacturing plants to serve the pharmaceutical industry.
Although it is likely to be some time before the therapeutic proteins produced by the transgenic hens are tested directly on patients, Jervis is confident in the technique.
“Hen eggs have been used for vaccine manufacture for over 30 years. Our gene delivery system is being developed for use in human gene therapy and so is designed to meet extremely stringent safety profiles. Also, recent approval of ATryn [recombinant human antithrombin] by GTC Biotherapeutics (transgenic goats) means regulators are familiar with transgenic bioproduction.”

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