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An
international team of scientists at the University of Munich have
produced genetically engineered pigs that could help save human
lives. For the first time their cells have been modified to protect
them from destruction by human killer cells.
The pig
is considered the best suited for organ transplant, although as
with other tissue transplants the potential of rejection poses a
great challenge.
The human
immune system is designed to protect against intruders, which means
that transplanted tissues are also usually attacked until they are
destroyed. This is especially true in the case of xenotransplantation.
The body's natural killer cells (NK-cells) quickly and efficiently
eliminate foreign or infected cells. Due to their differing molecular
structure the surface of the pig cells contains molecules which
cannot bind to the human NK-receptors and thus be destroyed.
Instead,
the genetically modified pig cells carry the human MHC-Class-1-molecule
HLA-E on their surface, which bind to the retardant NK-cell receptors.
This hinders the activation of the defense cells and the healthy
cells are therefore not attacked. When these cells together with
human
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NK-cells
were cultivated, they remained largely intact and not destroyed as
would normal pig cells do.
Researchers
are working around the world to engineer pigs to become more suitable
for organ donation. Lord Winston, head of the Institute of Reproductive
and Developmental Biology at Hammersmith Hospital in London, and
colleagues successfully created transgenic pig sperm; the genetically
engineered pigs will contain six human genes in order to decrease
the chances that the pigs' organs will be rejected by human bodies.
But as British regulations prohibit breeding genetically modified
animals on agricultural land, the researchers will breed the pigs
in Missouri, and hope to produce a fully modified animal within
the next two years then begin clinical trials to demonstrate that
the genetically engineered organs are safe for human transplant.
You can
get more information at: www.germany.info/Vertretung/usa/en/_PR/GIC/
2009/01/21_Pigs_S,archiveCtx=1992696.html www.naturalnews.com/025414.html
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