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Study Shows Differences in Natural Immunity
in Cloned Pigs By David Elstein
October 26, 2004
WASHINGTON, Oct. 26--Studies by scientists with the
U.S. Department of Agriculture and the
University of Missouri indicate that the
natural immune system of young cloned pigs does not appear to fight diseases as
effectively as the immune system of non-cloned pigs.
Carroll of USDA's Agricultural Research
Service collaborated with University of Missouri-Columbia scientists Bart
Carter, Randall Prather and Scott Korte on the study. The pigs were cloned at
the University of Missouri by Prather and his colleagues. ARS is USDA's chief
scientific research agency. At the time of the study, Carroll worked at ARS'
Physiology Research Unit in Columbia, but he is now based at the agency's
Research Unit in Lubbock, Texas.
In their experiments, the scientists gave a naturally occurring
toxin called lipopolysaccharide to seven young, cloned pigs and 11 genetically
similar, non-cloned pigs. Although the non-cloned pigs' immune response was
adequate, the cloned pigs' immune system did not produce sufficient quantities
of natural proteins called cytokines, which fight infections. Animals must have
an adequate cytokine response to survive infections.
Cloned pigs, as well as cloned cows, have been known to have a
higher-than-normal number of deaths around the time of birth. Many die from
As newborns, both the cloned and non-cloned pigs received some
disease protection through their consumption of colostrum, a natural substance
passed to a newborn pig via its mother's milk. The colostrum helps protect the
young animal until its own immune system begins to function.
The cloned pigs are being used only for research purposes, and
are not part of the food supply.