of the human body's most important defense mechanisms, antibodies,
could come from a surprising new source, cows. Antibodies are one
of the ways our bodies fight off disease and infection. Antibodies
extracted from healthy blood can be used to treat people suffering
from certain diseases.
are often in short supply because they have to come from donated
blood. To overcome the shortage, scientists are actively researching
ways to produce human antibodies without humans.
In 2001, a
calf genetically engineered to produce human antibodies was born.
Scientists created an artificial chromosome and inserted it into
the genetic makeup of the calf. The artificial chromosome carries
human immune system genes, making it possible for the cow to produce
human antibodies in its blood.
About 20 of
these "transchromosomic" calves have been cloned, creating
a mini-herd of animals that produce human antibodies in their blood.
Scientists say the calves are an important step toward a steady
supply of antibodies.
to be overcome before the antibodies can be used in humans though.
Researchers have to figure out a way for the cows' blood to be purified,
to ensure no viruses or other problems are passed along with the
Source: Briggs, Helen.
BBC News Online. "Cows Born with Human DNA." http://news.bbc.co.uk/2/hi/science/nature/2183200.stm September 2002.