The GM hens whose eggs are designed to save lives

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The GM hens whose eggs are designed to save lives

By BETH HALE

 

Last updated at 22:00pm on 14th January 2007

 

Scientists have created a breed of designer chickens with eggs that

can produce life-saving drugs.

 

 

The breakthrough could help the fight against diseases such as cancer

and dramatically cut the cost of treatments.

 

 

But it will worry opponents of the genetic modification techniques

the scientists used.

 

 

The 500-strong flock was bred at Edinburgh's Roslin Institute, the

birthplace of Dolly the cloned sheep.

 

 

The chickens' DNA was altered so that their eggs contained complex

medicinal proteins. The proteins can be extracted to make drugs for

humans.

 

 

It is the first time scientists have successfully manipulated the

birds' DNA so that their characteristics are passed down the

generations. Previously the ability to make the valuable proteins had

vanished in a generation or two.

 

 

The scientists announced the successful production of anti-cancer

proteins in the whites of eggs 18 months ago.

 

 

Since then they have made dramatic strides which could lead to the

creation of egg drug factories. Such a development would slash

production costs.

 

 

At present, disease-beating proteins are mainly created in vats of

bacteria or other cells that have been genetically modified. This

makes extracting the relevant proteins expensive and difficult.

 

 

The Roslin scientists used some of the GM chickens to create

interferon. A drug based on this human protein is widely used to

treat multiple sclerosis.

 

 

The chickens have also been used to create an antibody that could

tackle skin cancer.

 

 

The " avian transgenic manufacturing " project is a joint venture

between the Roslin Institute and the biotechnology firms Viragen and

Oxford BioMedica.

 

 

Last night Karen Jervis, of Viragen Scotland, held out the prospect

of many more treatments.

 

" We have bred several generations of chickens so far, and they all

keep producing high concentrations of pharmaceuticals, " said Dr

Jervis.

 

 

" This is potentially a very powerful new way to produce specialised

drugs. We chose two candidates, but we have got others coming

through.

 

 

" What we want is to produce as many possibilities as we can to show

that we can apply the technology to many drugs.

 

 

" Theoretically there is no restriction on the type of drugs that can

be produced. "

 

 

The project involved extracting cockerel embryos from hens and

injecting them into surrogate eggs. The embryos - which were just a

small cluster of cells - were then given a virus that had been

genetically modified to contain human genes. These human genes

carried the blueprint for the disease-beating proteins.

 

 

The " founder cockerels " were later mated with normal female hens and

the resultant eggs were found to contain the desired proteins.

 

It is likely to be several years before the breakthrough could have a

commercial application.

 

 

Any resultant drugs would have to go through the rigorous trial

procedures faced by any new drug. This can take six years.

 

 

The research is to be published tomorrow in the U. S. journal,

Proceedings of the National Academy of Sciences.