HIV is a challenging target for vaccine researchers for many reasons, not the least of which is its lack of stability. The surface proteins of the virus frequently change, keeping the immune system from recognizing it–and keeping researchers from selecting a surface protein as a stable target for a vaccine.
At least one area on the surface of the virus, however, seems to remain fairly stable across all variants of HIV: a site located on the surface spikes the virus uses to bind to and infect immune cells. Now, two teams of researchers have found antibodies that attach to this site, preventing the virus from binding to immune cells, and have highlighted ways this discovery may lead to new advances in HIV vaccine designs.
The antibodies are found in the blood serum of many individuals infected with HIV. The researchers selected HIV-1 isolates encompassing all of the major circulating subtypes of the virus, and showed that these antibodies could bind to–and neutralize–more than 90% of them. That broad ability to neutralize so many variants of the virus is because of the stability of the binding site, which remains the same among nearly all strains. Therefore, a vaccine that could “train” the human immune system to generate similar antibodies could provide protection against the majority of circulating HIV variants.
In addition, the researchers note, the process they used to discover these antibodies may lead to similar advances for other infectious diseases.
The two research teams included NIAID scientists from the VRC, the Laboratory of Immunoregulation, and the Division of Clinical Research, all in Bethesda, Md.; as well as researchers from Beth Israel Deaconess Medical Center in Boston; Columbia University in New York; Harvard Medical School and Harvard School of Public Health in Boston; The Rockefeller University in New York City; and University of Washington in Seattle. Both papers are available via the Science Express website as of July 8, 2010: http://www.sciencexpress.org.