New Anti-HIV Weapons Found in Immune System
THURSDAY July 8, 2010 -- Scientists report they've discovered possible new weapons in the war against HIV: antibody "soldiers" in the immune system that might prevent the AIDS virus from invading human cells.
According to the researchers, these newly found antibodies connect with and neutralize more than 90 percent of a group of HIV-1 strains, involving all major genetic subtypes of the virus.
That breadth of activity could potentially move research closer toward development of an HIV vaccine, although that goal still remains years away, at best, experts say.
The findings "show that the immune system can make very potent antibodies against HIV," said Dr. John Mascola, a vaccine researcher and co-author of two new studies published online July 8 in the journal Science.
"We are trying to understand why they exist in some patients and not others. That will help us in the vaccine design process," said Mascola.
Antibodies are warriors in the body's immune system that work to prevent infection. "Neutralizing" antibodies bind to germs and try to disable them, explained Ralph Pantophlet, an immunologist and assistant professor at Simon Fraser University in Burnaby, British Columbia, Canada.
With HIV, the antibodies are in a continual race to adjust to the virus, which evolves to escape detection. "The reason the antibodies generally do not work so well is because they're always playing catch up," said Pantophlet, who is familiar with the findings of the new studies.
However, some people's antibodies are known to cope especially well with HIV, although even these rare patients can't get rid of the virus entirely, Pantophlet said.
In the new studies, researchers report on three antibodies that appear to have major powers to fight off HIV. In a sense, the antibodies gum up a lock that the virus tries to pick to get into healthy cells, said Mascola, deputy director of the Vaccine Research Center at the U.S. National Institutes of Allergy and Infectious Diseases.
However, making antibodies in large enough quantities to boost the immune system remains a challenge, said Pantophlet.
While researchers haven't given up on that prospect, some think it's more feasible to use the new findings as another avenue to an AIDS vaccine. The idea would be to teach the body to produce the antibodies so the person is protected when exposed to the virus, Mascola said.
But that won't happen for some time, if at all. "Developing a vaccine always takes a fairly long period of research with some trial and error," Mascola said.
"The goal is to vaccinate individuals and have their own immune systems make an antibody like this," he said. "To do that, we have to design a new vaccine, study it first in animal models, and then try it in small scale human studies, and see if it does what we expect it to do. That takes a quite a bit of time and effort."
To learn more about the immune system, see the U.S. National Library of Medicine.
Posted: July 2010