Scientists have discovered how HIV hides itself inside the human body without triggering the body’s natural defences.
The study from Wellcome Trust, the Medical Research Council and University College London discovered a molecular “invisibility cloak”, which stops the body from launching an immune response against the virus.
However when these molecules are removed using a drug, the body recognises the foreign body and attacks it, the researchers wrote in the journal Nature.
Professor Greg Towers, a Senior Research Fellow at UCL and lead author of the study, said: “HIV is extremely adept at hiding from our body’s natural defences, which is part of the reason the virus is so dangerous.
“Now we’ve identified the virus’ invisibility cloak, and how to expose it, we’ve uncovered a weakness that could be exploited for new HIV treatments.”
The body’s immune system should detect the presence of bacteria and viruses, triggering an antiviral response.
But the way HIV infects vital white blood cells and replicates without triggering this alarm system has puzzled scientists since the discovery of the virus.
Prof Towers and his team identified two molecules inside host cells that are recruited by HIV after infection that shield the virus and stop the innate immune system from kicking into action.
When these molecules were removed, whether by depletion from infected cells or by blocking their recruitment using an experimental drug, the scientists found HIV was exposed and an antivirus immune response was triggered.
Prof Towers said that by targeting the cloaking molecules, the virus finds it harder to mutate and become resistant to this treatment approach, which has been a significant problem with standard HIV therapies.
He added: “There’s a great deal more research needed, but the potential for this approach is huge – as a possible treatment in itself, but also as a complement to existing therapies.
“We’re also interested to see whether blocking these cloaking molecules can help to boost immune responses to experimental vaccines against HIV or be used to protect against HIV transmission.
“The hope is that one day we may be able develop a treatment that helps the body to clear the virus before the infection is able to take hold.”
The experimental drug used in the study is based on cyclosporine, a drug widely used to prevent organ rejection in transplant patients because of its ability to dampen the immune response.
Cyclosporines have been shown to block the replication of HIV and other viruses but are not suitable for treating infected patients because of their negative effects on the immune system.
But by modifying the drug, the team managed to block the effects of the two cloaking molecules without suppressing any immune activity.