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Cloned cows able to make human immune proteins

Cloned cows could provide a source of life-saving immune proteins that are often in short supply for those who need them, according to a study in today's edition of Nature Biotechnology.

The cows possess genes that allow them to make human immune proteins, called antibodies, that are only available from human donors. As many as 50,000 Americans with primary immune deficiency, a life-threatening condition that impairs the body's ability to make antibodies, need US$3,000-a-month doses of the proteins to fight off infections.

The cloned cows offer hope for a steady supply of human antibodies, which were in shortage from 1997 through 2000 and could be again in 2003, according to Tom Moran, president of the Immune Deficiency Foundation in Baltimore. The foundation helped ration antibody supplies during the shortage, when about 40 percent of the group's members became ill as a result of insufficient immune protection from infections.

"I'm not certain yet that the immune proteins produced by cows will replace human sources, but they could at least improve existing products and relieve some of the demand on the human supply," Moran said.

The antibodies were produced in cows cloned by Hematech Inc, based in Sioux Falls, South Dakota, and the Kirin Brewery Co.

Pharmaceutical Research Laboratory in Japan. James Robl, president of Hematech, replaced the cows' own genetic immune production blueprints with a human chromosome containing genes for immune proteins.

When the cloned cows are infected with bacteria or viruses, they respond by making human antibodies rather than cow antibodies. These antibodies can be harvested from the cow's tissues for use in people, Robl said.

"The advantage of this technique is that it gives you an expandable production system, and you can make products that wouldn't be able to make in humans," he said.

Unlike humans, the cows could be infected with toxins like botulism to make human antibodies. Cows could make antibodies that could also be used to treat dangerous viral infections, like hepatitis C, or organisms unleashed by bioterrorists, Robl said.

They could also be used to treat bacteria that have developed resistance to conventional antibiotics.

"Bacteria can develop resistance to drugs, but not to antibodies," Robl said.
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