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Could a cure for AIDS be on the horizon?
Genetically engineered human stem cells can hunt down and ‘kill’ HIV
inside the body
PUBLISHED: 09:56 GMT, 13 April 2012 | UPDATED:
09:56 GMT, 13 April 2012
Human stem cells can be genetically engineered
into ‘warrior’ cells that fight HIV – and the new cells can attack
HIV-infected cells inside a living creature.
The breakthrough, by UCLA scientists, is hoped
to be the first step towards a treatment that can eradicate HIV from an
infected patient.
Much HIV research focuses on vaccines or drugs
that slow the virus’s progress – but this new technique could offer hope
of a ‘cure’.
The study, published April 12 in the journal
PLoS Pathogens, demonstrates for the first time that engineering stem
cells to form immune cells that target HIV is effective in suppressing
the virus in living tissues.
‘We believe that this study lays the groundwork
for the potential use of this type of an approach in combating HIV
infection in infected individuals, in hopes of eradicating the virus
from the body,’ said lead researcher Scott G Kitchen.
The scientists took CD8 cytotoxic T lymphocytes
– the ‘killer’ T cells that help fight infection – from an HIV-infected
individual and identified the molecule which guides the T cell in
recognizing and killing HIV-infected cells.
However, these T cells, while able to destroy
HIV-infected cells, do not exist in great enough quantities to clear the
virus from the body.
So the researchers cloned the receptor and used
this to genetically engineer human blood stem cells. They then placed
the engineered stem cells into human thymus tissue that had been
implanted in mice, allowing them to study the reaction in a living
organism.
The engineered stem cells developed into a large
population of mature, multi-functional HIV-specific cells that could
specifically target cells containing HIV proteins.
The researchers also discovered that
HIV-specific T cell receptors have to be matched to an individual in
much the same way an organ is matched to a transplant patient.
In this current study, the researchers similarly
engineered human blood stem cells and found that they can form mature T
cells that can attack HIV in tissues where the virus resides and
replicates.
They did so by using a surrogate model, the
humanized mouse, in which HIV infection closely resembles the disease
and its progression in humans.
In a series of tests on the mice’s peripheral
blood, plasma and organs conducted two weeks and six weeks after
introducing the engineered cells, the researchers found that the number
of CD4 "helper" T cells – which become depleted as a result of HIV
infection – increased, while levels of HIV in the blood decreased.
‘We believe that this is the first step in
developing a more aggressive approach in correcting the defects in the
human T cell responses that allow HIV to persist in infected people,’
Kitchen said.
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