08-27-2002, 01:12 PM
08-27-2002, 05:22 PM
/27/2002 Double Knock-Out Pig Could Revolutionize Pig Farming For Transplantations - 8/23 PR Newswire
Earlier this year PPL announced the birth of pigs in which a single copy of the alpha 1,3 galactosyl transferase (GT) gene had been knocked out -- the single 'knock-out' pigs. This development is an extension of that work.
Four healthy piglets were born at PPL Therapeutics Inc, USA on 25 July, 2002 and continue to do well. A fifth piglet died shortly after birth of unknown causes. The gene that has been double 'knocked-out' in these pigs is responsible for making an enzyme that adds a sugar to the surface of pig cells which is recognised by the human immune system as foreign. This pig sugar (alpha 1,3 galactose) triggers an immune response in the human patient, leading to hyperacute rejection of the transplanted organ or cell within minutes. The ability to delete or 'knock-out' both copies of the gene, therefore, provides a vital step in producing pigs with organs and cells which can be used in humans. Because both copies of the gene have been inactivated, tissues from these pigs have been shown to be completely devoid of the pig sugar that cause the hyperacute rejection to take place.
As announced earlier in the year, PPL is in the process of 'spinning out' its regenerative medicine programme (xenografts and stem cells), of which the knock-out pig programme is part, in order to focus its resources on its lead protein products, recAAT for hereditary emphysema, Fibrin 1, and BSSL. It is also the Board's belief that the resources required to bring a product to market in the area of regenerative medicine will be significant and beyond the current resources of PPL. The announcement today, however, recognises another key milestone for PPL in the area of xenotransplantation and demonstrates the company's leading-edge position in this rapidly developing field. The company intends to have completed the spin-out by the end of the year.
As part of PPL's ongoing collaboration with the University of Pittsburgh's Thomas E. Starzl Transplant Institute, organs and cells from these double knock-out pigs will be used in pivotal transplantation studies aimed at testing for elimination of hyperacute rejection and long term survival of these xenografts.
The 'knock-out' work was carried out by PPL Therapeutics Inc, PPL's US subsidiary located in Blacksburg, Virginia, and was partly supported by an ATP Grant from the US Government's National Institute of Standards and Technology (NIST). In addition to these double knock-out pigs, the company has generated more than 60 male and female single gene GT knock-out pigs since the first litter was born in December 2001, demonstrating that this technology is now a reliable and reproducible tool for making very precise genetic changes in these animals.
David Ayares, COO and VP of Research at PPL Therapeutics Inc said:
"This advance brings us closer to the promise of a potential solution to the world-wide shortage of organs and cells for transplantation."
Geoff Cook, Chief Executive Officer said:
"This is an important step for PPL demonstrating our leading position in this exciting area. The news will support our efforts in spinning out PPL's regenerative medicine business, that will then enable us to focus on our core protein work."
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