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A
spinach
packed with HIV suppressing proteins??
Researchers have investigated the idea
of using plants as "factories" to produce and deliver
vaccines, but Dr. Alexander Karasev of Thomas Jefferson University
in Philadelphia, Pennsylvania is among the first to focus
on HIV.
The Pennsylvania researchers focused on
"tat"
-- a protein that helps HIV reproduce within cells and, at
the same, works to suppress the activity of the human immune
system. For this reason, tat
is an ideal target for the development of both a preventive
vaccine and as a treatment for those already infected with
HIV.
But why use plants to produce and deliver
such a vaccine? The essential point is that vaccines are a
very expensive business, so anything that can drive the cost
down will be beneficial. Vaccines that grow naturally in plants
would be much cheaper to harvest than those produced in the
lab.
In their experiments, Karasev's team introduced
a gene expressing the HIV tat protein into a common plant
virus. Once spinach was infected with the virus, it began
to work as a "plant factory" for production of tat.
Human trials involving plant-based delivery
of a rabies vaccine have shown that the human immune response
can be "primed'' to recognize rabies using this method,
and Karasev is hopeful that researchers can reproduce the
same results with HIV.
Annual Meeting
of the American Society for Microbiology Orlando, FA May 22,
2001
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