A VIRUS that kills every one of its victims, by wiping out part of their
immune system, has been accidentally created by an Australian research team. The
virus, a modified mousepox, does not affect humans, but it is closely related to
smallpox, raising fears that the technology could be used in biowarfare.
The discovery highlights a growing problem. How do you stop terrorists taking
legitimate research and adapting it for their own nefarious purposes?
The Australian researchers had no intention of producing a killer virus. They
were merely trying to make a mouse contraceptive vaccine for pest control. 鈥淏ut
it鈥檚 a good way to show how to alter smallpox to make it more virulent,鈥� says
Ken Alibek, former second-in-command of the civilian branch of the Soviet
germ-warfare programme.
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Ron Jackson of CSIRO鈥檚 wildlife division and Ian Ramshaw at the Australian
National University, both in Canberra, inserted into a mousepox virus a gene
that creates large amounts of interleukin 4. IL-4 is a molecule that occurs
naturally in the body. As part of a study aimed at creating a contraceptive
vaccine, they were trying to stimulate antibodies against mouse eggs, which
would make the animals infertile. The mousepox virus was merely a vehicle for
transporting the egg proteins into mice to trigger an antibody response. The
researchers added the gene for IL-4 to boost antibody production. The surprise
was that it totally suppressed the 鈥渃ell-mediated response鈥濃�攖he arm of the
immune system that combats viral infection.
Mousepox normally causes only mild symptoms in the type of mice used in the
study, but with the IL-4 gene added it wiped out all the animals in nine days.
鈥淚t would be safe to assume that if some idiot did put human IL-4 into human
smallpox they鈥檇 increase the lethality quite dramatically,鈥� says Jackson.
鈥淪eeing the consequences of what happened in the mice, I wouldn鈥檛 be the one
who鈥檇 want to do the experiment.鈥�
To make matters worse, the engineered virus also appears unnaturally
resistant to attempts to vaccinate the mice. A vaccine that would normally
protect mouse strains that are susceptible to the virus only worked in half the
mice exposed to the killer version. 鈥淚t鈥檚 surprising how very, very bad the
virus is,鈥� says Ann Hill, a vaccine researcher from Oregon Health Sciences
University in Portland. If bioterrorists created a human version of the virus,
vaccination programmes would be of limited use.
Alibek, who now works on developing novel treatments for anthrax for the
defence contractor Hadron in Virginia, says this highlights the drawback of
working on vaccines against bioweapons rather than treatments. 鈥淚鈥檇 say any
vaccine could be overcome by one or another genetically engineered virus or
bacterium,鈥� he says.
Is it possible that research into new vaccines against cancer and other
diseases could inadvertently create lethal human viruses? Many of the most
promising modern vaccines depend on viruses to transport genes into the body,
and contain genes that directly alter the immune response. But researchers have
not been too concerned because the evidence until now suggested that changes in
the genetic make-up of viruses invariably makes them less virulent, not more.
One way to reduce the risk, says Gary Nabel of the National Institutes of
Health, is to use only viruses that cannot replicate. 鈥淭here are some
replication-competent [viral vaccines] around, but there is increasing concern
about their use,鈥� he says.
Defence experts are also worried about preserving the freedom to publish
medical findings while trying to stop the information falling into the wrong
hands. According to D. A. Henderson, a former US presidential adviser, and
director of the Center for Civilian Biodefense Studies at Johns Hopkins
University in Baltimore, what are effectively blueprints for making
microorganisms more harmful regularly appear in unclassified journals. 鈥淚 can鈥檛
for the life of me figure out how we are going to deal with this,鈥� he says.
The Australian researchers consulted their country鈥檚 Department of Defence
before submitting the work for publication, and only decided to go ahead after
considerable thought. A report will appear in a February issue of the
Journal of Virology. 鈥淲e wanted to warn the general population that this
potentially dangerous technology is available,鈥� says Jackson. 鈥淲e wanted to make
it clear to the scientific community that they should be careful, that it is not
too difficult to create severe organisms.鈥�
