http://www.newswire.ca/releases/August2002/22/c4812.html
PPL Therapeutics Plc - World's first cloned double knock-out pigs lack both copies of gene involved in hyperacute rejection in humans
LONDON, England, Aug. 22 /CNW/ - PPL Therapeutics Plc ("PPL"), one of the
leading biopharmaceutical companies in the application of transgenic
technologies is pleased to announce it has produced the World's first double
gene "knock-out" piglets which were born as a result of using PPL's
proprietary gene targeting technology and nuclear transfer (cloning). 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."
Full text of release is the above accompanied by "Notes to Editors"
and can be requested by e-mailing ppl@hspr.co.uk |
