WHAT: New discoveries about anti-HIV antibodies may bring researchers a step closer to creating an effective HIV vaccine, according to a new paper co-authored by scientists at the Vaccine Research Center of the National Institute of Allergy and Infectious Diseases (NIAID), part of the National Institutes of Health.

Scientists know that an HIV-neutralizing antibody called b12 binds to gp120, an HIV surface protein, at one of the few areas of the virus that does not mutate: the site where gp120 initially attaches to human immune cells (http://www3.niaid.nih.gov/news/newsreleases/2007/b12antibody.htm). It was thought that exposing the human immune system to this site on gp120 would generate antibodies that, like b12, can neutralize HIV. Studies have found that for unknown reasons, however, the vast majority of antibodies that recognize this site do not block the virus from infecting cells. Now a new study solves this puzzle, suggesting that antibodies must home in precisely on the site of initial gp120 attachment to successfully neutralize HIV…