Scientists have made a genetic breakthrough they say could block infection from the HIV virus, offering a promising new avenue for a potential vaccine.

A team at Scripps Research Institute in Florida announced Wednesday in the journal Nature they had altered the DNA of monkeys to create a molecule that prevents the virus from invading immune cells and turning them into HIV factories.

The researchers said the drug provided protection against all types of HIV and at very high doses.

"Our compound is the broadest and most potent entry inhibitor described so far," said Michael Farzan, professor of infectious diseases at Scripps.

Researchers have been on a 30-year quest to find a vaccine and cure for HIV, the virus that causes AIDS. Dr. Louis Picker of Oregon Heath & Science University has developed a vaccine that was successful in rhesus monkeys. He's also working on a cure for the virus, which has posed an enormous challenge because it keeps on changing.

Most research into a vaccine is based on firing up the immune system to battle the virus. But Farzan's study used gene therapy to introduce new DNA inside muscle cells, creating molecules that mimic the immune cells that are invaded by HIV. The decoys, outfitted with two key receptors, effectively deactivate the virus, making it incapable of infecting other cells.

This approach is more effective than relying on the body's antibodies to fight off HIV, Farzan said. But it could present risks. It's not known how the body would react to the decoys.

In an email to The Oregonian/OregonLive, Picker called Farzan's announcement "a very significant advance that will generate much interest in the field." But he said more extensive work is needed to back up the finding.

Farzan only tested the compound on four rhesus macaques. It could be years before tests on humans could be carried out.

The research was based on work by a long list of scientists from Harvard, Princeton, Rockefeller University, the University of Southern California and the University of Pennsylvania and other institutions.

-- Lynne Terry

lterry@oregonian.com

503-221-8503

@LynnePDX