In a new study, researchers reported that two antibodies to HIV could prove to be keys to a vaccine to stop the progress of the infection to AIDS. The Scripps Research Institute-based team found the antibodies, called PG9 and PG16, in people who remained asymptomatic after infection.

"This is opening up a whole new area of science," said Dr. Seth F. Berkley, president and CEO of the International AIDS Vaccine Initiative, which financed and coordinated the study.

To find the antibodies, scientists analyzed blood samples from more than 1,800 HIV-positive people from Thailand, Australia and Africa who had not developed severe disease for at least three years after infection. Researchers at San Francisco-based Monogram Biosciences tested the blood samples to determine which contained antibodies most resistant to HIV infection. These samples were further analyzed by a team from Theraclone Sciences, which isolated the antibodies responsible for the resistance.

Researchers found the antibodies PG9 and PG16 in one African patient were broadly neutralizing - inhibiting the activity of the 162 separate HIV strains that researchers tested. The antibodies bind to regions of two HIV surface proteins, gp120 and gp41, that HIV uses to invade cells, according to lead author Dennis Burton of Scripps in La Jolla, Calif., and colleagues. These regions of the virus have never before been targeted by HIV/AIDS vaccine candidates.

The antibodies could potentially be used as a treatment for people developing severe symptoms from HIV infection. A vaccine based on the discovery, using either synthetic or natural molecules, remains the ultimate goal.

The full report, "Broad and Potent Neutralizing Antibodies from an African Donor Reveal a New HIV-1 Vaccine Target," was published online ahead of the print edition of Science (2009;doi:10.1126/science.1178746).