Haynes said one surprising finding is about an antibody -- a soldier of the immune system -- that helps protect against influenza infection. Ironically, the antibody appears to boost the likelihood of HIV infection, he said.
Another finding was that higher levels of antibodies that home in on a particular region of HIV's outer shell, called V1V2, were associated with lower rates of infection with the virus.
This and other information in the study may help researchers come up with theories about where to go next with vaccine development, Baden said. Among other things, it can reveal parts of the immune system that can be most useful in battling the transmission of HIV.
Vaccines are available to fight other kinds of viruses, such as measles and influenza. HIV is unique, however, because it inserts its genetic material into the body's cells.
"When a person gets infected with HIV, that genetic material goes underground," Haynes said. "It's invisible to the body's immune system."
Another challenge is that the virus mutates, becoming a moving target.
"It changes so rapidly in the person who gets infected that even when the immune system does try to control it, in most people the immune system is always playing catch up," Haynes said.
There's more on HIV/AIDS at the U.S. National Library of Medicine.
SOURCES: Barton Haynes, M.D., director, Duke Human Vaccine Institute, Duke University, Durham, N.C.; and Lindsey Baden, M.D., infectious physician, Brigham and Women's Hospital, Boston. April 5, 2012, The New England Journal of Medicine.
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