An HIV vaccination has been found to completely clear the disease from the bodies of monkeys, raising hopes that a cure for the virus has finally been found.
The vaccine, developed by a team of scientists at the Oregon Health & Science University, was tested in rhesus macaques with simian immunodeficiency virus (SIV), which causes Aids in monkeys.
Researchers now hope to test their vaccine on humans with HIV as it is a potential cure for the disease.
Louis Picker, associate director of the OHSU Vaccine and Gene Therapy Institute, said: "To date, HIV infection has only been cured in a very small number of highly-publicised but unusual clinical cases in which HIV-infected individuals were treated with anti-viral medicines very early after the onset of infection or received a stem cell transplant to combat cancer.
"This latest research suggests that certain immune responses elicited by a new vaccine may also have the ability to completely remove HIV from the body."
Published in the journal Nature, the vaccine uses a virus called cytomegalovirus (CMV), which is carried by a large proportion of the population.
The team engineered CMV so that the body's T-cells, which are a key component of its immune system, were able to seek and destroy SIV-infected cells.
Hopeful of HIV cure
Around half of the monkeys infected with SIV after being given the vaccine were rid of all trace of the disease over time.
Picker said: "Through this method we were able to teach the monkey's body to better 'prepare its defences' to combat the disease.
"Our vaccine mobilised a T-cell response that was able to overtake the SIV invaders in 50% of the cases treated. Moreover, in those cases with a positive response, our testing suggests SIV was banished from the host. We are hopeful that pairing our modified CMV vector with HIV will lead to a similar result in humans."
The authors note: "Whether the residual virus that maintains these infections is vulnerable to clearance is a question of central importance to the future management of millions of HIV-infected individuals."
Earlier this year, doctors at the International AIDS Society Conference in Kuala Lumpur announced that two men had been cured of HIV through stem cell transplants.
Both received stem cell transplants to treat the blood cancer lymphoma, with cells used to replace bone marrow. After they stopped taking antiretroviral drugs, both were declared HIV-free.