[BEIJING] Suppressing the body's natural defence mechanisms may help fight HIV/AIDS, say researchers in last week's PLoS Medicine (2 January).

They say blocking production of a chemical that helps regulate people's immunity could make vaccines more effective.

The study focused on a molecule called SOCS1 that suppresses chemical messages used by the immune system.

This helps stop people's immune systems from causing damage to their own bodies, for example through excessive inflammation. However, the chemical could also be preventing people infected with HIV from responding fast enough to the HIV virus.

This could help explain why, so far, no HIV vaccine that seeks to stimulate immune responses has been successful.

"Vaccines work very well in dealing with some pathogens, but for HIV, the natural immune response usually fails," says lead author Si-Yi Chen of Baylor College of Medicine in Houston, United States.

Chen's team showed that by switching SOCS1 off in the white blood cells of mice, they could induce an effective, long-term immune response to HIV.

Chen says researchers might be able to develop an HIV vaccine that elicits the required response if the immune system's "brakes were taken off " by blocking SOCS1 production.

He says the method could also be used to develop vaccines against other pathogens.

However, Barney Graham, a vaccine researcher at the US National Institutes of Health, warns in PLoS Medicine that the safety of the approach needs to be assessed.

"It will be important to show that SOCS1 inhibition is temporary, and that normal regulation of immune responses is maintained following the vaccination," says Graham.