HIV antibodies 'have potent impact'

A potential new HIV treatment has a
"profound and unprecedented" impact on
the virus, according to animal studies
published in the journal Nature.
Potent antibodies were able to wipe a hybrid
of human and monkey immunodeficiency
viruses from the bloodstream of monkeys
within days.
The findings could "revolutionise" the search
for an HIV cure, say experts.
The US researchers said trials in patients with
HIV now needed to take place.
The immune system produces precisely
targeted antibodies to take out HIV, but the
virus is able to rapidly mutate to evade the
immune assault.
However, some antibodies have been
discovered that target the "conserved" parts of
HIV - those that the virus struggles to change
because they are vital for it to function.
'Undetectable'
Two groups, from Harvard Medical School and
the National Institute of Allergy and Infectious
Diseases, performed the first trials of these
antibodies.
They used rhesus macaques that had been
infected with simian-human immunodeficiency
virus (SHIV), a blend of HIV and the monkey
equivalent.
Data from the Harvard team showed that
injection of the antibodies drove SHIV from
the bloodstream until it reached undetectable
levels after three to seven days.
The effect lasted for one to three months, but
in three monkeys the virus did not return to
the blood during the 250-day study.
Prof Dan Barouch told the BBC: "The effect
with these potent antibodies is profound and
unprecedented. It's probably as large an
antiviral therapeutic effect as has ever been
seen.
"But we have to make sure we don't overhype
and the limitation is the study is in animals,
not humans."
The antibodies were also able to attack the
virus in some tissues. Drugs can assault the
virus in the blood during normal HIV
treatment, but the virus can hide in other
parts of the body.
These early findings raise the prospect of using
antibodies to clear these tissues as well.
Similar results were produced by the team at
the National Institute of Allergy and Infectious
Diseases
'Revolutionise'
HIV infection is incurable, although taking a
daily dose of medication can keep the virus in
check, giving patients a near-normal life
expectancy.
The antibodies will be tested in human clinical
trials and if successful they could be used
alongside antiretroviral drugs as a treatment.
It may also be possible to devise a vaccine that
could train the immune system to produce
these antibodies.
However, both these ideas are dependent on
human trials being successful.
Commenting on the findings, Prof Louis Picker
and Prof Steven Deeks said: "The findings of
these two papers could revolutionise efforts to
cure HIV."
However, they warned that HIV was so prone
to mutation that it was "likely that some
people will harbour viruses that are resistant
to one or more" of the antibodies.