LONDON -- The company that created Dolly the cloned sheep announced Wednesday it has produced the world's first transgenic cloned piglets.
Scottish biotechnology firm PPL Therapeutics said each of the five piglets has a "foreign marker gene" in its DNA structure. This marks a major step toward the production of genetically engineered pig organs for use in human transplants, according to the company.
Although the firm cloned its first pigs last year, they were not transgenically modified. This modification is a vital element in the development of technology to stop the human immune system from rejecting transplanted pig organs as foreign.
In a statement, PPL said the pigs' birth demonstrates the feasibility of producing so-called "knock-out" pigs, in which the alpha 1-3 gal transferase gene is inactivated. When active, this gene would cause the human immune system to reject a transplanted pig organ.
Alan Colman, PPL's research director, said the company now has the ability to produce a pig that could become the industry standard for xenotransplantation, or transplantation from a non-human donor.
The firm announced the cloning success just one day after it was forced to drop plans to raise 45 million British pounds (US$64.5 million) because of market conditions. PPL is now considering other ways of raising money.
Recent reports have been skeptical about the chances of success with xenotransplantation, which carries the risk that animal viruses could be transmitted to humans. However a company spokesman told Reuters Health: "The viral threat is not considered significant."
Most of PPL's work on xenografts is done by the company's U.S. staff in Blacksburg, Virginia, and is supported by the U.S. government's National Institute of Standards and Technology.
