Scientists from Cornell and Scripps Research Institute have announced a breakthrough in understanding the mechanism HIV uses to infect humans, opening the door to creating an effective AIDS vaccine. It is hard to underestimate the significance of their feat.

AIDS is the most deadly global disease of our time, having killed well over 30 million people around the world since it was first identified in 1981. Another 35 million carry the disease, which also has inflicted an immense economic toll.

AIDS is spread through mother’s breast milk, sexual intercourse, contaminated needles and other ways.

Although the death count from AIDS and the new infection rate have declined dramatically in the past eight years, thanks to the widespread availability of anti-AIDS drugs and public health education, there is no way to prevent its spread through human contact. Roughly 2.5 million new cases are reported each year.

More than 20 years of intense research into a vaccine that could inoculate humans against HIV and so prevent AIDS have failed to come up with an answer. This failure has happened in large part because the virus has evolved a complex and elusive protein envelope that allows it to enter cells. Once the HIV virus gets past the cell’s immune system, its outer envelope, in effect, falls apart, frustrating laboratory efforts to study its structure.

Two papers in the Nov. 1 issue of Science magazine, published by the American Association for the Advancement of Science, explain how researchers from Scripps in La Jolla, Calif., and Weill Cornell Medical College in New York City, were able to stabilize the HIV envelope protein and subject it to study by different methods that have produced strikingly similar results.

Two studies using cryo-electron microscopy and one using X-ray crystallography produced high-resolution pictures of the molecular structure of the virus’ outer envelope.

These studies have allowed researchers at Scripps and Weill Corner to begin identifying sites that could be attacked by a vaccine that would prevent the HIV entry mechanism from functioning.

“These structures provide the most complete and detailed pictures of the HIV Envelope glycoprotein to date,” Andrew Ward of the Scripps Research Institute tells us. He is a lead author of the new papers. “The goal now is to digest these details and use this knowledge to design the next generation of HIV vaccine candidates. While there are no guarantees that these will work, the HIV research community is certainly better armed for the battle.”

The prospects for success against AIDS have never looked better.