February 24, 2005
Wednesday at the 12th Conference on Retroviruses and Opportunistic Infections in Boston, US scientists announced the discovery of a key element in the workings of HIV that could lead to vaccines against the virus. Stephen Harrison, head of a research team at Howard Hughes Medical Institute, led the study, which was conducted at Boston Children's Hospital and Harvard Medical School.
The researchers developed a three-dimensional image of the protein gp120, which is part of HIV's membrane, before it metamorphoses itself and attaches to a cell's CD4 receptors. After gp120 attaches to the receptors, HIV is able to penetrate the cell's interior and reproduce.
"Knowing how gp120 changes shape is a new route to inhibiting HIV by using compounds that inhibit the shape change. The findings will also help us understand why it's so hard to make an HIV vaccine, and will help us start strategizing about new approaches to vaccine development," Harrison said.
A key focus of the conference is vaccine treatments that stimulate the body, at the cellular level, to defend itself. Yet despite the promise of such cellular vaccines, real prevention of HIV's attack requires stimulating the immune system to produce virus-destroying antibodies before HIV enters cells, said Dr. Anthony Fauci, director of the US National Institute of Allergy and Infectious Diseases. "A safe and effective HIV vaccine is critical to the control of HIV globally, and is the most important and difficult scientific challenge facing AIDS researchers today," Fauci said.
The full report by Harrison and colleagues, "Structure of an Unliganded Simian Immunodeficiency Virus gp120 Core," is published in Nature (2005;433:834-841).