Earlier this week a team led by scientists at the Vaccine Research Center, a part of the National Institutes of Health (NIH), discovered an area on the human immunodeficiency virus (HIV) for a vaccine to target!
HIV works by attacking and killing vital cells within our immune system known as T-helper cells. These cells play an important role in the immune system by supporting other immune system cells that help suppress or regulate immune system responses. T-helper cells also kill cells that have been infected with germs.
Without T-helper cells, many other immune system cells cannot work properly, including B-cells that are responsible for making antibodies. Over time, the number of T-helper cells drops so low that the risk of infection and disease greatly increases, and the symptoms of acquired immune deficiency syndrome (AIDS) appear.
The new target, called the fusion peptide, is part of HIV that helps the virus fuse with a cell. The fusion peptide has a much simpler structure than other sites on the virus that HIV vaccine scientists have studied.
The research team first examined the blood of an HIV-infected person to explore its ability to stop the virus from infecting other cells. The blood was good at neutralizing HIV but did not target any of the vulnerable spots on the virus where broadly neutralizing HIV antibodies were known to bind.
The researchers isolated a powerful broadly neutralizing HIV antibodies in the blood that they named VRC34.01, and found that it binds to the fusion peptide and a sugar molecule. The scientists then crystallized the antibody while it was bound to the virus. This allowed them to characterize in atomic-level detail how VRC34.01 attaches to HIV and revealed that the antibody stops the virus from infecting a cell by binding to a key cell-surface molecule!
Researchers also screened the blood of 24 other HIV-infected volunteers and found that blood samples from 10 people targeted a similar binding site as VRC34.01.
The scientists and research team at the Vaccine Research Center are now working to create a vaccine designed to elicit antibodies similar to the VRC34.01 antibody.