Study on mice shows promise in drive to develop HIV vaccine
As scientists struggle to find a vaccine to prevent infection with the AIDS virus, a study in mice suggests hope for a new approach -- one that scientists now want to test in people.
The treated mice in the study appeared to have 100pc protection against HIV. But that doesn't mean the strategy will work in people.
"This is a very important paper," says the US government's AIDS chief, Dr Anthony Fauci. He did not take part in the research.
The study involved injecting mice with a protective gene, an idea that's been tested against HIV infection in animals for a decade. Researchers reported the results in mice yesterday in the journal 'Nature', on the eve of World Aids Day. They hope to test the approach in people in a couple of years. Another research team reported similar success in monkeys in 2009.
A traditional vaccine works by masquerading as a germ, training the body's immune system to build specific defences in case the real germ shows up.
Those defences are generally antibodies, which are proteins in the blood that have just the right shape to grab on to parts of an invading virus. Once that happens, the virus can't establish a lasting infection and is cleared from the body.
Scientists have identified antibodies that neutralise a wide range of HIV strains, but they've had trouble getting people's immune systems to create them with a vaccine.
The gene-injection goal is straightforward. Rather than trying to train a person's immune system to devise effective antibodies, why not just give a person genes for those proteins? The genes can slip into cells in muscle or some other tissue and make them pump out lots of the antibodies.
The study was carried out by David Baltimore and colleagues at the California Institute of Technology.
Ordinary mice don't get infected with HIV. So the research used mice that carried human immune system cells.
Researchers couldn't completely rule out the possibility of infection, but said that their tests found no evidence of it.