How do these carefree cluckers do it? Well, by a little manipulation of their genes. Scientists have been able to insert a lentivirus carrier, with its viral coding sequences deleted and replaced with other genes for making specific proteins, into a fertilized embryo of a newly laid egg. The inserted genes are placed with the albumin (major egg white protein) production gene then the egg is normally incubated to hatching. (Visual representation here).
The goal is to produce a chirping chick that will grow into a cockeral and sire hundreds of transgenic hens that will be able to lay eggs containing a specific protein such as an antibody for treating melanoma or an immune system protein that attacks viruses. Success rates have been relatively positive.
The process of transgenic animals producing specific proteins extends to other animals such as goats producing the protein in spider silk and cows producing growth hormone. The protein is produced in milk and egg white as these contain few other proteins and are thus easily extracted. The benefit of using chickens is that they have a much shorter life cycle and can produce over 300 eggs a year. Thus a window of opportunity has opened to produce affordable anti-cancer drugs which are currently prohibitively expensive. In fact it’s as cheap as chicken feed; literally. Essentially chicken feed is being used in a chicken bioreactor to produce proteins for the basis of drug production.
When will these egg-produced anti-cancer drugs be available? Probably not for at least another 15 years.
Primary References:
Genetically Modified chickens lay drugs in eggs *Click Here*
Chicken ‘Pharming’ yields eggs containing therapeutic proteins for potential use in treating malignant melanoma and other cancers *Click Here*
Secondary References:
Anti-cancer chicken eggs produced *Click Here*
Further Reading:
Competitive bioreactor hens on the horizon *Click Here*Third protein successfully expressed in transgenic chicken egg *Click Here*
Sasha Laws-King (4179386)
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