A preprint from the upcoming issue of March 27, 2000

Carbon-Copy Pigs Are Latest Milestone in Organ
Transplant Research

PPL Therapeutics, Inc., of Blacksburg, Va., announced on March 14 that it had achieved the world's first successful cloning of pigs from adult cells. Pigs are a particularly difficult species to clone because cloning is a very inefficient process and a sow must have a minimum number of viable fetuses to carry any to term. The five piglets born on March 5, say PPL researchers, mark an important milestone in the development of genetically engineered pigs to supply tissues and organs for transplant into humans. Because they share with humans relatively similar physiologies, pigs are considered a potentially valuable source of transplant organs--hearts and kidneys, for example--that are in critically short supply.

One of the main technical barriers to such "xenotransplants" is the "hyperacute rejection" reaction from the human immune system, which recognizes a particular sugar complex on the surface of pig cells as foreign. One particular pig gene is responsible for this tell-tale sugar, and researchers hope that organs from a genetically engineered pig lacking this gene could be transplanted without triggering the host's immune system. A U.S. subsidiary of London-based PPL Therapeutics Plc, PPL received a 1999 award from the NIST Advanced Technology Program to develop the technology to clone "knock-out" pigs--swine with that specific gene inactivated. In addition, more genes will have to be introduced into pig cells to prevent more delayed rejection responses.

The use of pig organs would offer tremendous health, economic and social benefits by providing sufficient organs to meet demand, reducing the tens of billions of dollars now spent annually caring for patients with organ failure, and improving their quality of life. In their ATP application, PPL projected a market for animal transplants of nearly $6.5 billion within 10 years of launch. In addition, the new technology will create new industries and enable advances in other fields, such as treatment of vascular disease, the science of embryology, the development of animal models for human diseases, and livestock improvement.

Media Contact:
Michael Baum, (301) 975-2763

 

 

 

Last updated: March 17, 2000
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