Vaccine 'clears HIV-like virus' in monkeys

A vaccine for the monkey equivalent of HIV
appears to eradicate the virus, a study
suggests.
Research published in the journal Nature
has shown that vaccinated monkeys can clear
Simian Immunodeficiency Virus (SIV) infection
from their bodies.
It was effective in nine of the 16 monkeys that
were inoculated.
The US scientists say they now want to use a
similar approach to test a vaccine for HIV in
humans.
Prof Louis Picker, from the Vaccine and Gene
Therapy Institute at Oregon Health and Science
University, said: "It's always tough to claim
eradication - there could always be a cell
which we didn't analyse that has the virus in
it. But for the most part, with very stringent
criteria... there was no virus left in the body
of these monkeys."

Search and destroy
The research team looked at an aggressive
form of virus called SIVmac239, which is up to
100 times more deadly than HIV.
Infected monkeys usually die within two years,
but in some inoculated primates the virus did
not take hold.
The vaccine is based on another virus called
cytomegalovirus (CMV), which belongs to the
herpes family.
It used the infectious power of CMV to sweep
throughout the body. But instead of causing
disease, it has been modified to spur the
immune system into action to fight off the SIV
molecules.
"It maintains an armed force, that patrols all
the tissues of the body, all the time,
indefinitely," explained Prof Picker.
The researchers gave rhesus macaque monkeys
the vaccine, and then exposed them to SIV.
They found that at first the infection began to
establish and spread. But then the monkeys'
bodies started to respond, searching out and
destroying all signs of the virus.
Of the monkeys that successfully responded to
the vaccine, they were still clear of infection
between one-and-a-half and three years later.
Prof Picker said his team was still trying to
work out why the vaccination worked in only
about half of the monkeys.
"It could be the fact that SIV is so pathogenic
that this is the best you are ever going to get.
"There is a battle going on, and half the time
the vaccine wins and half the time it doesn't,"
he said.

Human trials
The researchers are now testing the vaccine to
see if it can be used after SIV exposure to
treat and potentially cure infected monkeys.
They also want to see if the technique could
work in humans.
Prof Picker said: "In order to make a human
version we have to make sure it is absolutely
safe. Cont. Reading