11th August 2011.
Scientists may have found a cure for the common cold, flu, HIV – and almost
any other virus you can think of.
A drug that homes in on infected cells and makes them self-destruct has been
created in the laboratory.
Its hit list includes human rhinoviruses – the bugs behind half of colds in
adults and almost all colds in children – flu, polio, a stomach bug and
deadly dengue fever.
But the drug, known by the acronym DRACO, is also expected to zap measles
and German measles, cold sores, rabies and even HIV – and could be on
pharmacy shelves in a decade.
Researcher Mike Rider said: ‘It’s certainly possible that there’s some virus
that we aren’t able to treat but we haven’t found it yet.
'The discovery of antibiotics revolutionised the treatment of bacterial
infections and we hope that this will revolutionise the treatment of viral
‘There aren’t very many anti-viral drugs out there at the moment.’
Dr Rider, of the Massachusetts Institute of Technology in the U.S., has
exploited cells’ natural defences against infection.
When viruses infect the body, they hijack cells’ internal machinery to make
copy after copy of themselves. During this procedure they create long
double-stranded strings of the genetic material RNA.
Our cells usually defend themselves by making proteins that latch on to the
RNA and stop the virus from breeding.
But many viruses can outsmart this defence system.
So Dr Rider has also harnessed a second natural process called apoptosis, in
which diseased cells commit suicide.
The bottom row of images show viruses killing untreated
human cells, but in the top pictures the drug used means there is no
infection and cells are clear.
His drug homes in on cells
with double-stranded RNA, stops the infection in its tracks and then kills
the cells to finish off the infection.
What is more, healthy cells
are untouched, the journal PLoS ONE reports.
In lab tests, DRACO killed
15 viruses, including germs behind the common cold and two types of flu. It
also saved the lives of mice given a dose of flu that should have killed
Amazingly, it works so quickly
that if taken early enough it should stop any symptoms from appearing. Tests
show it also wards off viruses, meaning it could stop people from becoming
ill in the first place.
British experts welcomed the
breakthrough but warned that the drug works in such an unusual way that it
would have to go through years of testing before it is considered safe
enough to test on people for the first time.
THE DRACOs TECHNOLOGY: HOW
Many viruses can outsmart human cells natural defence system - but this
technology doesn't let it.
When viruses infect a cell,
they take over its cellular machinery for their own purpose - to create more
copies of the virus.
During this process, the
viruses create long strings of double-stranded RNA (dsRNA), which is not
found in human or other animal cells.
As part of their natural
defence, human cells have proteins that latch onto dsRNA, setting off a
cascade of reactions that stops the virus from replicating itself.
But, many viruses can
outsmart that system by blocking one of the steps further down the cascade.
This new technology works
by combining a dsRNA-binding protein with another protein that makes cells
undergo apoptosis (programmed cell suicide) — launched, for example, when a
cell determines it is en route to becoming cancerous.
So, when one end of the
DRACO binds to dsRNA, it signals the other end of the DRACO to initiate cell
Each DRACO also includes a
'delivery tag,' taken from naturally occurring proteins, that allows it to
cross cell membranes and enter any human or animal cell.
However, if no dsRNA is
present, DRACO leaves the cell unharmed.