Infection-fighting proteins could lead to HIV vaccine 'within years'

By Leigh Dayton
The Australian

September 04, 2009 01:40pm


Hope discovery could lead to vaccine


HIV researchers have made the biggest breakthrough in 15 years, identifying two powerful antibodies that appear to fight all types of the virus - a development that brings new hope of a vaccine.

The Australian reports the US team has discovered two infection-fighting proteins in blood taken from an African who was already infected with HIV but did not show any of the symptoms. The scientists found these antibodies apparently neutralised all major groups, or clades, of HIV.

By determining where the antibodies bind to the virus, they know which parts of the virus to target with vaccines. They also identified what genes the donor's body used to build the "broadly neutralising antibodies".

The knowledge could lead to gene therapies to treat people already infected with HIV, as well as vaccines to protect people from infection.

Worldwide, 33 million people are infected with HIV, including about 16,600 Australians. The virus is estimated to kill about 2 million people a year, having already claimed 25 million.

The findings were reported overnight in the journal Science by an international consortium led by immunologist Dennis Burton of the Scripps Research Institute in La Jolla, California, and the newly established Ragon Institute in Boston, Massachusetts.

Trial vaccines developed over the past 15 years have proved ineffective or even dangerous.

In November 2007, a global vaccine trial involving 3000 people at high risk of HIV infection, including 19 Australians, was halted when scientists discovered that the vaccine appeared to make them more susceptible to HIV infection. The reason remains unclear.

Virologist Damian Purcell, head of Melbourne University's Molecular Virology Laboratory, cautioned that the research was in its early days, but said vaccines and therapies could be on the market in 10 years, at the latest.

"This finding demonstrates that, after all the disappointments over the last 15 years, scientists have gone back to basics and we're looking at fundamental questions like what are the best targets in the virus," Professor Purcell said.

Until now, researchers had been unable to find an Achilles heel on the virus that remained the same across clades.

Part of the problem is that HIV mutates rapidly in the community and even in an infected person's body.

Further, numerous clades circulated in different regions of the world. And because no one is known to have completely eliminated an HIV infection, it's not known which elements of the body's immune response must be triggered to get rid of, or clear, the virus.