Scientists Locate Antibodies that Can Stop Advance of AIDS

Los Angeles Times (09.04.09): Thomas H. Maugh II

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).