NIH scientists discover mechanism that protects HIV
The research team from the U.S. National Institutes of Health examined the spikes jutting out of the surface of HIV. Each spike contains a set of three identical, bulb-shaped proteins called gp120 that can be closed together or spread apart. Some of the sites targeted by HIV neutralizing antibodies are hidden when the three gp120s, also known as the trimer, are closed. The trimer stays closed until HIV binds to a cell.
The researchers found that certain amino acids on the gp120 protein are able to stabilize the trimer in its closed position in a process called sulfation. During sulfation, the amino acids acquire a sulfur atom surrounded by four oxygen atoms to keep the trimer closed.
The NIH researchers found that by either blocking or increasing sulfation of the amino acids they were able to change the sensitivity of the virus to different neutralizing antibodies.
The team suggests that if the synthesized gp120 used in HIV research were completely sulfated during manufacture, the product would more closely mirror the way the immune system sees unbound HIV. This could help scientists develop a more effective HIV vaccine.
Additionally, the researchers said that full sulfation of gp120 could allow scientists to crystalize the molecule more easily, advancing the design of HIV vaccines.