Gene could offer the body a natural defence against HIV

A gene that provides a natural defence against the virus responsible for Aids could pave the way for new treatments for HIV infection, scientists said yesterday.

Researchers found that the gene, CEM15, stops HIV in its tracks if the virus is slightly modified. Normally, HIV overcomes CEM15 by producing a protein called Vif that suppresses its activity. Without Vif, the gene interferes with the HIV life cycle and renders any new virus particles non-infectious.

Professor Michael Malim, at King's College, London, and Dr Ann Sheehy, at the University of Pennsylvania, studied cells infected with a form of HIV lacking Vif. Their research ­ reported in the internet edition of the journal Nature ­ found that CEM15 made the virus harmless. Professor Malim said: "These are very significant findings. Previous studies have shown that Vif is crucial in infection and neutralises some sort of defence system in healthy cells. Our research has identified CEM15 as a key component of the system in question. If we can find a way to block the action of Vif, it would allow CEM15 to work properly and prevent HIV from spreading."

Therapies using multiple anti-viral drugs are currently the best way to treat HIV, but the virus develops resistance to the drugs in about half of all treated patients. Professor Malim said: "It's very ambitious, but we may see Vif developed as a new target for therapy in the next 10 years."

Meanwhile, British scientists have stumbled upon a molecule which could be the body's secret weapon against cancer. The protein, found in the kidney can starve tumours by blocking their blood supply.

Scientists led by Dr Dave Bates and Dr Steve Harper at Bristol University believe it may be effective against a range of cancers, as well as artery disease and diabetes. It could also lead to the design of new anti-cancer drugs.

The molecule is a form of a protein called vascular endothelial growth factor (VEGF). VEGF promotes angiogenesis, the growth of blood vessels which feed tumours and are vital to their survival.

Usually it is only seen in diseased tissue. But it also occurs in healthy kidneys, where it does not appear to generate tumours.

The scientists' research led them to discover a different form of VEGF, called VEGF 165b, which inhibits the original and prevents angiogenesis in the kidney.