Durham, N.C. — For the first time, Duke University Medical Center scientists have isolated an important antibody that could help with the development of an AIDS vaccine.

Antibodies are proteins in our bodies that our immune system uses to attack bacteria or viruses. The protein called the 2F5-like antibody, the one Duke researchers isolated, is a gold standard for what an HIV vaccine needs. Until now, however, no one had ever found it circulating in the blood of infected people.

“The 2F5-like antibody is valuable because we know, from past research, it can neutralize 80 percent of transmitted HIV viruses. Now that it has been found, we may be able to find ways to duplicate or enhance it and boost the body's immune system,” said Georgia Tomaras, PhD, associate professor of surgery, immunology and molecular genetics and microbiology in the Duke Human Vaccine Institute and the senior author of the study.

2F5-like antibodies are neutralizing antibodies, one of the body's responses to infection. Only a small amount of people with HIV make these antibodies, and they typically appear months after initial transmission of the virus. At that point, it is often too late to help.

Tomaras, working closely with lead author Xiaoying Shen, and a team of researchers examined the antibodies present in 300 patients infected with HIV-1. They found only one patient who had developed 2F5-like antibodies.

“We discovered that the 2F5-like antibody was strong enough to block multiple strains of HIV in the lab, but it's not clear if it played any part in the patient's ability to control the virus,” Tomaras said.

Since the immune cells that produce these antibodies have been identified and isolated, the goal is to understand how to trigger the cells to routinely make these antibodies before someone is infected.

The research was funded by the National Institutes of Health and the Duke Center for AIDS Research and appears online in the Journal of Virology.