Washington: An experimental vaccine candidate may have the potential to stimulate the immune system to block HIV infection, according to new research.

The findings may represent a leap forward in the effort to develop a vaccine against HIV, which has so far struggled to elicit antibodies that can effectively fight off different strains of the virus, according to three papers published on Thursday in the US journals Cell and Science.

"The results are pretty spectacular," said Dennis Burton of the Scripps Research Institute (TSRI), who led one of the studies, Xinhua reported.

Currently, many vaccines use a dead or inactive version of the disease-causing microbe itself to trigger antibody production, but immunisations with "native" HIV proteins are ineffective in triggering an effective immune response, due to HIV's ability to evade detection from the immune system and mutate rapidly into new strains.

This challenge has led many researchers to believe that a successful AIDS vaccine will need to consist of a series of related but slightly different proteins called immunogens (substances that induce a specific immune response) to train the body to produce broadly neutralising antibodies, a special class of immune system molecules that can bind to and neutralise a wide range of globally occurring HIV variants.

In the new studies, the researchers tested one of these potential proteins, an immunogen called eOD-GT8 60mer, which would bind to and activate B cells needed to fight HIV.

Using a technique called B cell sorting, the researchers showed that immunisation with eOD-GT8 60mer caused two different mouse models to produce antibody "precursors", which have some of the traits necessary to recognise and block HIV infection.

This suggested that eOD-GT8 60mer could be a good candidate to serve as the first in a series of immunisations against HIV, the researchers said.

The US National Institutes of Health has funded the research. (IANS)