Word: ppl
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Dates: during 2000-2009
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...snap-out, snap-in simplicity. The problem is, once the donor organ is stitched in place, the body rebels, rejecting it even more violently than it would a human graft. "A pig heart transplanted in a person would turn black within minutes," says David Ayares, a research director with PPL Therapeutics, the biotech firm based in Scotland, New Zealand and Virginia that helped clone Dolly and also produced the piglets...
What causes porcine organs to be rejected so quickly is a sugar molecule on the surface of pig cells that identifies the tissue as unmistakably nonhuman. When the immune system spots this marker, it musters its defenses. PPL scientists recently succeeded in finding the gene responsible for the sugar and knocking it out of the nucleus of a pig cell. Their next step would be to extract that nucleus, insert it into a hollowed-out pig ovum and insert the ovum into the womb of a host sow. The sugar-free piglet that was eventually born could then be cloned...
...cloned piglets PPL introduced to the world last week were created in just this way, though for this first experiment in pig replication, the scientists left the sugar genes intact. "We wanted to work with pristine cells to make sure our cloning technique would indeed work," says Ayares. Now that they've proved it does, the scientists plan to raise the bar and try the same procedure with modified genes...
...technology: Knocking out the genes prevents a human recipient from rejecting a pig organ transplant. "This opens the door to making modified pigs whose organs and cells can be successfully transplanted into humans - the only near-term solution to solving the worldwide organ shortage crisis," said a spokesman for PPL Therapeutics, the company behind the experiments. Although moral critics of the practice will blanch, the purpose of PPL's cloning experiments - the latest being conducted by the company's U.S. division, in Blacksburg, Va., with a federal government research grant - has been directed not at creating photocopy humans...