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By Claire Ainsworth
Vast fields of maize could soon be churning
out antibodies for preventing sexually transmitted diseases.
Researchers at Epicyte, a biotech company
in San Diego, say their technology promises to make the mass
production of therapeutic antibodies easier and cheaper. At
the moment, therapeutic antibodies are produced using hamster
ovary cells - an expensive method that produces limited amounts.
But Epicyte's new "plantibody"
technology allows the DNA that codes for antibodies to be
introduced into crop plants
such as maize. The antibodies are only produced in the maize
kernels, making it easy to extract them using current maize-processing
methods.
Secretory antibodies are proteins of the
immune system that coat the wet, warm parts of the body to
protect them from attack.
Both the fight against sexually transmitted
diseases, such as herpes, and effort to stop pregnancy would
be helped if women's reproductive tracts were "supplemented"
with appropriate antibodies.
Epicyte has now produced anti-sperm antibodies
in gel form. But such products have
to be made in bulk to be cost-effective.
The antibody for herpes, HX8, works by
sticking to the virus and blocking its entry into cells, and
has proved highly effective in animal tests.
Although condoms provide some protection
against herpes infection, they are not 100 per cent reliable.
But HX8 can provide protection in the vagina for 24 hours.
Epicyte is also developing antibodies that block HIV transmission
and the virus that causes genital warts.
The HX8 genes have already been transferred
into maize, and Epicyte plans to start clinical trials of
the antibody next year. Hiatt hopes plantibodies will be cheap
enough for consumers to buy them over the counter. "That's
the ultimate goal," he says.
New
Scientist October 3, 2001
The Economist
September 8, 2001 83-84
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