FRIDAY, July 2 (HealthDay News) -- Research in mice suggests
that scientists may have a new lead on using gene therapy against
the virus that causes AIDS.
The researchers tinkered with human stem cells and then inserted
them into mice where they multiplied into immune system cells that
provided protection against infection with HIV, according to a
study released online July 2 in
The results are unlike typical research in animals because the
mice have been "humanized": They have human immune systems and
resisted a human disease. Still, until research is conducted on
humans, there's no way to know if the treatment will work in
people. And it may be years until that happens.
But there are high hopes. "It's a one-shot treatment if it
works," noted study co-author Paula Cannon, associate professor of
molecular microbiology at the University of Southern
In gene therapy, doctors try to coax the human body into doing
something differently by tweaking its genetic structure. To treat
HIV, the virus that causes AIDS, scientists have been experimenting
with using gene therapy to boost the immune system.
In the new study, researchers engineered human stem cells --
cells that create other cells -- to lock a kind of "door" that
allows HIV to enter.
The door, a "receptor" on immune cells linked to a gene known as
CCR5, is disabled in a very small percentage of people, and those
people appear to be virtually immune to HIV.
"That's like nature telling us how to cure AIDS," Cannon reasoned. The idea of the experimental treatment is "to engineer a patient's own cells so they'd be resistant to HIV" in much the same way.
The researchers did this by "cutting" a gene in the stem cells.
These genetically manipulated cells did try and repair the injury,
Cannon noted, but they didn't do a good job and HIV's way in was
The researchers inserted these tweaked stem cells into the
humanized mice and other mice, then tried to infect them with
According to the scientists, the genetically engineered stem
cells went on to create mature immune system cells, such as
T-cells, in the humanized mice. After a couple of weeks, these new
immune cells appeared to provide protection against HIV. The cells
grew greatly in number, offering fewer targets for the virus to
Meanwhile, the virus made its usual successful attack on other
mice that had not undergone the procedure.
Rowena Johnston, vice president of research with the Foundation
for AIDS Research (amfAR) in New York City, said gene therapy is
starting to show "real promise," and this study reveals a new side
of its potential.
"One of the doctrines of gene therapy in the context of HIV has been the assumption that every relevant cell must be transformed," she said. "This research demonstrates that need not be the case."
But could this approach work in humans? The answer to that is
yet to come, Cannon said.
"We want to make sure that this works, and a good place to start is in a patient population who already have their stem cells taken out," she said. Cannon and her colleagues would like to test it by piggybacking on a gene therapy treatment in which the stem cells of HIV-positive lymphoma patients are removed, tinkered with and then put back into their bodies.
Cannon doesn't know how much the gene therapy will cost, but one
estimate puts the expense of this type of treatment for HIV at
$100,000. But if it allows HIV patients to avoid taking drugs for
the rest of their lives, she said, it should be cost-effective over
Whatever the case, the treatment isn't around the bend. Cannon
said it could be four years before research in humans can begin.
But another treatment that uses a similar strategy on a type of
immune cell is already being tested in people.
There's more on gene therapy at the
U.S. National Library of Medicine.