July 8, 2010 -- After years of virtually no progress, researchers have taken an important step toward developing a vaccine for HIV.
Scientists from the National Institute of Allergy and Infectious Disease Viral Research Center discovered two antibodies that can bind to a part of the human immunodeficiency virus and neutralize it. Past research has identified other antibodies that also bind to the virus, but these were only able to neutralize 4 out of 10 strains. Researchers found that these newly discovered antibodies, called VRC01 and VRC02, can neutralize 9 out of 10 strains.
Experts say this is very significant, since it means that these antibodies stopped virtually all 190 strains of HIV from damaging the immune system. One of the biggest challenges researchers and vaccine developers have faced over the years is the ability of HIV to mutate very quickly, rendering most antibodies ineffective against new strains.
They hope that the discovery of these antibodies can help lead eventually to development of an HIV vaccine, though they caution there's no way to predict when, or even if, that could happen.
"It's an important step in the right direction of adding a degree of precision to vaccine development," said Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health. "But there's no way to tell when a vaccine could happen," he added.
The ability to neutralize HIV broadly is a finding other researchers see as encouraging and exciting as well.
"Vaccine development has been one disappointment after another," said Dr. Paul Volberding, vice chair of the department of medicine at the University of California, San Francisco. Volberding was not involved in the research. "As we learn more about the very specific nature of these regions that are unchanging from one virus to the next we can keep moving forward."
New developments like this, while preliminary, are also heartening to people living with HIV/AIDS, like New York attorney Jim Williams.
Those With HIV Hold Hope for Others
He knows there may not be much a new vaccine can do for people like him who are already infected, but he's glad that others may not have to live with HIV.
"I wouldn't want anyone to go through what I've gone through," Williams said.
While he feels very fortunate that the virus hasn't made him sick, he wishes he could say the same about his antiretroviral medication.
"One moment you're fine, the next moment you're going off on somebody," he said. "I also had very vivid dreams, and I had to stop taking the subway. I needed to walk so I could be sure I could find a bathroom."
While he's on different medication now that doesn't have such bad side effects, he still longs for a vaccine.
"I'm constantly frustrated that there's no vaccine yet," he said.
Antibodies Can Guide Future Vaccine Development
Scientists involved in vaccine development share Williams' frustration, but think the discovery of VRC01 and VRC02 is a step forward.
"These antibodies can serve as guides to make vaccines for HIV and will be tools to try and block infections in some clinical studies and develop new prevention strategies," said Dr. Gary Nabel, one of the study's co-authors and the director of the Vaccine Research Center, National Institute of Allergy and Infectious Disease, National Institutes of Health.
"Once you begin to see how things really attach and work, you can get a crystal structure of it. And once you have that, it begins to lead to discovery of new antibodies you can use in humans," said Dr. Margaret Fischl, professor of medicine at the University of Miami School of Medicine. She is not affiliated with the NIAID study.
Now that the structure of the vulnerable region of the virus is known, researchers say there are a couple of logical next steps in vaccine development, though again, they stress there's no way to tell if or when these milestones may become reality.
"It would be huge if a year or two from now if we were able to put it into a vaccine and we vaccinated people, and we were able to make a neutralizing vaccine," said Fauci.
"If you have an antibody that looks interesting, probably the next step is to make enough of it to use in small-scale trials and then you would use it to see if it actually works in humans," said Volberding. "Test it on animals, and then see if it's worth the huge investment of a long-term study on humans."
Discovery May be Promising for Treatment and Prevention
Experts also say this discovery may also eventually have therapeutic value.
"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," said Nabel. "The hope would be that we could suppress the virus and increase life span and improve quality of life."
"You can't totally eradicate the virus from the body, but you may be able to lead to a cure that completely controls the virus. You may be infected, but the virus doesn't damage the immune system," she said.
Another way this antibody can potentially be used is to prevent the virus from taking hold in people who may have been exposed to it through tainted blood or engaging in high-risk behavior.
"We think there's a good chance it can abort an infection entirely," said Nabel.
Others aren't so sure.
"It's hard to imagine it would be used in people that are already infected," said Volberding. "The treatments we have for infected people are working quite nicely."
He also doesn't believe there's much value in using it after people have been exposed to HIV.
"Post-exposure prophylaxis is done with drugs used to treat the infection and that's been effective," he said.
Regardless of how the vaccine is used, Jim Williams can't wait for the day when it's available, because he wants others to be spared the horror of hearing the doctor say they're HIV positive.
"It was devastating to me when I was diagnosed. Those two words change your life forever."