Aussie scientists stumble across HIV therapy

BRISBANE - Australian scientists have accidentally stumbled upon a simple way to dramatically stimulate immunity to deadly viruses like HIV in what's considered a major discovery in the fight against Aids.

The researchers were initially so taken aback by their chance find, they repeated the study several times before they could convince themselves it actually worked.

"We just couldn't believe it," said Stephen Kent, of the University of Melbourne's Department of Microbiology and Immunology.

"It was one of those sort of serendipitous ... lucky things. We're very excited about it.

"We think it's a very promising technique that offers hope for a therapy for HIV and other chronic infections."

Associate Professor Kent said the researchers had initially set out to devise a test to judge how well an animal's immune system could fight HIV.

They extracted blood from vaccinated laboratory animals and then coated the cells with HIV peptide markers - which tell the immune system a cell is infected by the virus.

When they injected the peptide-coated blood back into the animals - to create the illusion the cells were infected by HIV even though they weren't - they found it triggered a huge immune response.

"When we analysed HIV-specific immunity in the weeks following ... a marked enhancement of virus-specific immunity was induced," Prof Kent said.

"So the test we were trying to devise was actually a vaccine in itself which was totally unexpected."

The researchers have successfully tested the discovery in both mice and monkeys.

They hope to begin human trials in Sydney and Melbourne within two years.

The therapy would involve injections of the patient's own blood after it is treated with peptides found on the surface of cells infected by the virus.

"What we're looking at ... is a therapy that boosts people's immune systems against the virus," Prof Kent said.

"HIV ... is difficult to get rid of completely but if it's kept at bay by some sort of immune therapy it may not officially be cured but if that goes on for the person's life then it won't ever cause them any trouble.

"That's kind of the goal."

Prof Kent said the therapy had even proved effective against drug-resistant forms of the disease.

Most people with HIV are prescribed what's known as highly active anti-retroviral therapy (HAART), estimated to cost up to $A10,000 ($NZ11,000) a year.

The drugs have side effects like diarrhoea, nausea and rashes, and becoming resistant is a big problem.

"If we can work out an immune therapy that you might only have to take a few times a year, it would be a lot cheaper," Prof Kent said.

The researchers have aptly named the therapy - Overlapping Peptide Autologous Cells (OPAL) - in line with its Australian origins.

Their study - a collaboration with the Australian National University's John Curtin School of Medical Research - has been published in the latest international Journal of Virology.

They've been awarded National Health and Medical Research Council (NHMRC) funding of almost $A500,000 to refine the technique so that it can be studied in humans.

Prof Kent said the therapy had also shown promise as a treatment for other chronic infections like Hepatitis C.

- AAP