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Copyright © AIDS Center
2006

Discovery Helps Researchers Close In on HIV Vaccine

American scientists are touting a major stride toward a vaccine that can ward off HIV, after finding two key proteins that neutralize 91 percent of the virus' 190 strains.

The team of researchers with the National Institutes of Health's Vaccine Research Center hopes the antibody discovery can spur successful work toward a method of preventing HIV, which already afflicts an estimated 33 million people worldwide.

The discovery, published in this week's Science, is courtesy of Donor 45, an unidentified African-American man whose body produced the antibodies, called VRC01 and VRC02.

Scientists have already identified the 12 cells in his body that produced the proteins. If they can harness the mechanisms by which the antibodies were made, they might be able to create a vaccine that would spur anybody's body to make the HIV destroyers.

"We're going to be at this for a while," Gary Nabel, director of the center and a leader on this research, told The Wall Street Journal.

The last few years has seen a flurry of effort -- much of it futile -- toward creating a vaccine for HIV, much like those that helped eradicate small pox and polio. Until now, however, single antibodies only appeared to block one or two HIV strains.

Trials on the first promising vaccine, AIDSVAX, were largely a disappointment. In American and Thai trials, the vaccine yielded success rates that varied from statistically insignificant to 30 percent.

In this case, researchers seem to have found a sweet spot on the surface of the human immunodeficiency virus.

"The antibodies attach to a virtually unchanging part of the virus, and this explains why they can neutralize such an extraordinary range of HIV strains," Dr. John Mascola, one of the study's researchers, said in a statement.

Turning these newly discovered antibodies into a useful HIV vaccine remains a tall order. Scientists would need to isolate the specific part of the virus that the antibodies latch onto, then craft a vaccine using that viral snippet to train the body to produce VRC01 and VRC02.

"It's an important step in the right direction of adding a degree of precision to vaccine development," Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, told ABC News. "But there's no way to tell when a vaccine could happen."

Now that scientists have a better understanding of the actual virus, and areas on its surface that appear vulnerable, new tactics in treating HIV/AIDS might also be an area for further research.

"In infected people, we may be looking at it in combination with medication and determine whether you can get more effective control of the virus and suppress it down to low levels," Nabel said. "The hope would be that we could suppress the virus and increase life span and improve quality of life".