US company Viragen, which is developing the antibody in collaboration with the Roslin Institute in Scotland (best known for cloning Dolly the sheep) and UK firm Oxford BioMedica, said the achievement brought the use of chickens as bioreactors for protein production a step closer. The ultimate aim is to make the antibody in chicken eggs.
Once running at scale, the companies believe that the eggs will form a reliable, efficient manufacturing vehicle for the antibody. According to the companies, eggs used as an alternative to standard biomanufacturing techniques such as mammalian cell culture would have advantages in ease of scale- up, lower costs of production and quality of the product produced.
This view ties in with a report published by TIFAC, which suggests that use of transgenic animals to make recombinant proteins is five to 10 times more economical in operational costs, as well as two to three times cheaper in startup costs, compared to cell culture production methods.
In the latest development, Viragen reported that the anti-GD3 antibody - designed to treat malignant melanoma - had been detected in the blood of a founder transgenic rooster after the gene coding for the protein was introduced using Oxford BioMedica's LentiVector delivery system.
The key objective now is to ensure that an intact, functional version of the antibody can handed down to subsequent generations of chickens that will form the production flock. Viragen said the technology had now progressed to a level that meant the company would be seeking discussions wuth regulatory agencies to determine the steps that will be required to bring the technology to the market.
Dr Helen Sang of the Roslin Institute said that the team has previously demonstrated that a reporter gene can be synthesised in the oviduct - the source of egg white proteins - of laying hens. But the new milestone is that a humanised antibody can be successfully incorporated into the birds' DNA.
"These results indicate that we are well advanced towards our stated target of tissue-specific expression of a therapeutic protein," she said.
Viragen said work has already begun on developing production in eggs of a second, unnamed therapeutic protein which has global sales of approximately $2 billion (€1.5bn).