HIV can be killed at early stage

Scientists have discovered a possible way to attack and kill the HIV virus. It involves wiping out the virus soon after infection, before it can begin to mutate and evade destruction.

Researchers from the University of Wisconsin-Madison have discovered that the body's immune system mounts a powerful defence during the first few weeks after infection. This initial killer T-cell response is eventually defeated by a small number of viruses that mutate and escape the onslaught.

"We have discovered a potentially promising new approach to attack the AIDS virus," stated Prof David Watkins, professor of pathology and laboratory medicine at the university. He describes the research in the current issue of Nature.

He and colleagues studied rhesus macaques infected with the monkey equivalent of HIV at the Wisconsin Regional Primate Research Centre in Madison. The viral strain in the monkeys remained unchanged for about two weeks after infection, up to the time that the killer T-cells began their attack.

The researchers studied the viral particles in the monkeys four weeks after infection and could find no trace of the original viral form. It had been replaced with another which had changes to the part of the virus - called the Tat protein - originally recognised and targeted by the killer T-cells. In effect it had become invisible to the immune cells.

Prof Watkins believes that a vaccine could be produced linked to the Tat protein and other regions of the virus that are recognised by the killer T-cells during the early stages of infection. This would sensitise the immune system, and if the person was subsequently infected, there would be an immediate attack that might wipe out the virus before it had a chance to mutate.