Ordinarily, when scientists want to produce proteins for use in medicine, they have to utilize techniques that are costly and complex. Recently, however, Scottish researchers have created genetically-modified hens that simply lay eggs containing significant quantities of such proteins.

A team at the University of Edinburgh's Roslin Institute has so far been focusing on producing two proteins in this fashion. The first, a human protein known as IFNalpha2a, has powerful antiviral and anti-cancer effects. The second, macrophage-CSF, has been shown to stimulate damaged tissues to repair themselves – both human and porcine (pig) versions of this one have been produced.

A simple purification system is used to extract the proteins from the whites of the eggs, which the modified chickens lay just as normal chickens would lay theirs. Currently, three such eggs are required in order to obtain clinically-relevant amounts of the proteins.

Given that chickens lay about 300 eggs annually, it is believed that the technology would be less expensive than current lower-yield techniques such as growing the proteins in mammalian cell cultures, or other approaches that require complex purification systems and more processing. And although previous studies have used genetically-modified goats, rabbits and chickens to produce therapeutic proteins in their milk or eggs, the Edinburgh hen system is reportedly more efficient, cost-effective and higher-yielding.

"We are not yet producing medicines for people, but this study shows that chickens are commercially viable for producing proteins suitable for drug discovery studies and other applications in biotechnology," says team member Prof. Helen Sang.

The technology is being commercially developed via the university's Roslin Technologies division, and is described in a paper that was recently published in the journal BMC Biotechnology.