Scientists discover vulnerable area on HIV that could lead to development of HIV/AIDS vaccine

Scientists on Wednesday announced they had identified a vulnerable area on HIV that might be susceptible to antibodies and could prevent the virus from infecting human cells, Reuters Health reports. The findings are published in the Feb. 15 issue of the journal Nature.

A team of researchers at NIH's National Institute of Allergy and Infectious Diseases, led by Peter Kwong, identified a protein called gp 120 on the surface of the virus that appears susceptible to attack by an antibody called b12. HIV enters CD4+ T cells through gp 120, but b12 could block the entry process and neutralize the virus, according to Reuters Health (Dunham, Reuters Health, 2/14). According to the San Francisco Chronicle, HIV continuously changes shape, making it difficult for an antibody to attach to the virus' surface (Russell, San Francisco Chronicle, 2/15). However, the gp 120 protein does not mutate (AFP/Globe and Mail, 2/15). Certain antibodies called "broadly neutralizing" antibodies -- which include b12 and for five years have been the focus of vaccine research -- have been shown to attack HIV regardless of the virus' mutations. Kwong and his team took X-rays of b12 as it attached to the virus and developed a three-dimensional map of the target site. Scientist might be able to clone the target site and create a vaccine that will allow the immune system to create HIV antibodies, the Chronicle reports. According to study co-author Dennis Burton -- an immunologist at the Scripps Howard Researcher Institute -- the b12 antibody in 1992 was isolated in the blood of an HIV-positive person who was identified as a long-term nonprogressor. Similar antibodies have since been discovered that target the same site on the virus, the Chronicle reports.

Reaction

Warner Greene, director of the San Francisco-based Gladstone Institute of Virology and Immunology, said the finding is "potentially ... very, very important." Greene added that the finding "provides a clear blueprint for future vaccine development efforts" (San Francisco Chronicle, 2/15). Kwong said, "Having that site and knowing that you can make antibodies against it means that a vaccine is possible." He added that the finding has taken the possibility of an HIV vaccine "from an impossible dream ... to something that is a (mere) technical barrier." Anthony Fauci, director of NIAID, said that although the findings are important, more studies in animals and humans are needed and that a vaccine will take several years to be developed. Fauci added, "I don't think we could really make substantial, fundamentally scientifically based progress until we got this very important information" (Reuters Health, 2/14). Wayne Koff -- a scientist at the International AIDS Vaccine Initiative, which co-sponsored the research -- said the findings are "evidence that an effective, preventive AIDS vaccine is possible" (AFP/Globe and Mail, 2/15).