Researchers said Wednesday they have mapped an "arms race" in the human body between the AIDS virus and powerful antibodies that fight it off - the latest of several recent scientific advances accelerating the pursuit of a vaccine.
In a study published in the journal Nature, researchers showed how a virus that had recently infected an African patient battled powerful proteins called "broadly neutralizing antibodies," which few HIV patients have but which can target thousands of strains of HIV.
The virus and antibodies changed and evolved time and time again in the patient, trying to outwit one another.
The fascinating back-and-forth one-upmanship between the virus and the antibodies, which the researchers documented by examining more than three years' worth of blood samples from the patient, is akin to an "arms race," said Barton Haynes, a leader of the research and director of the Duke Human Vaccine Institute at Duke University.
Following that battle allowed them to pinpoint how the powerful antibodies develop and evolve - a question that scientists have been seeking to answer for years.
The research could help in the development of a vaccine that would mimic the antibodies' evolution and ward off HIV, the virus that causes AIDS, Dr. Haynes said. "We have a full blueprint now for how those antibodies were made," he said.
The quest for an AIDS vaccine is one of the most vexing in all of science because unlike other viruses, HIV mutates frequently - even over the course of a week in a single patient - to outmaneuver antibodies that fight against it.
About 34 million people were living with HIV in 2011, and 1.7 million died, according to the Joint United Nations Programme on HIV/AIDS. About 2.5 million were newly infected with HIV that year.
Scientists have also been perplexed as to how broadly neutralizing antibodies develop - a critical question because they are able to target most strains of HIV.
Dozens of antibodies have been identified over the past few years. Yet only 20% of people infected with HIV ever develop them naturally. The researchers gained insight into how broadly neutralizing antibodies progress by studying blood samples from a very early stage of the patient's infection. That allowed them to pinpoint a part of the virus that triggered the beginning of their development.
By laying out how both the virus and the antibodies evolve, the research "opens up a very interesting strategy" for "a vaccine that mimics the evolution of the virus," said Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, the arm of the National Institutes of Health that oversees AIDS research. NIAID provided funding for the research.
The strategy would involve sequentially vaccinating a person with boosters designed to mimic the way the virus evolves, he said.
Broadly neutralizing antibodies take up to four years to develop in people who naturally develop them now. They don't rid an already infected person of HIV. Scientists hope a vaccine that induces these antibodies would protect uninfected people from the virus.
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