Scientists have identified a gene which they say may have the ability to prevent HIV, the virus that causes AIDS, from spreading after it enters the body.

In an early-stage study in the journal Nature, researchers said the gene, called MX2, appears to play a key role in how HIV is controlled in human cells, so using it could lead to the development of new, less toxic treatments that harness the body's natural defenses and mobilize them against the virus.

Although there are many more years of research ahead, Mike Malim, who co-led the research at King's College London, described the finding as "extremely exciting" and said it advanced scientists' understanding of how the HIV virus interacts with the immune system.

"Until now we knew very little about the MX2 gene, but now we recognize both its potent anti-viral function and a key point of vulnerability in the life cycle of HIV," he said in a statement about the study, published on Wednesday.

Some 34 million people worldwide are infected with the human immunodeficiency virus (HIV) that causes AIDS - the vast majority of them in poor and developing countries.

But while, particularly in wealthy nations, there are many effective drugs available that allow HIV patients to live long, healthy lives, they often have side-effects and drug resistance can become a problem with long-term use.

In this study, Malim and a team of researchers conducted experiments on human cells in the laboratory, introducing the HIV virus to two different cell lines - one in which the MX2 gene was "switched on", and in the other it which is was "silenced" - and then observing the effects.

They found that in the cells where MX2 was silenced, the AIDS virus replicated and spread, while in the cells where it was switched on, the HIV was unable to replicate and produce new viruses to spread.

Malim said the findings suggest MX2 is a key player in establishing viral control in people with HIV, and that armed with this new knowledge, there are two possible routes for potential drug development using the gene.

"It may be possible to develop either a molecule that mimics the role of MX2 or a drug which activates the gene's natural capabilities," he said.