In a major step forward for potential HIV prevention, new research shows that an experimental HIV vaccine may halt the development of the virus: it’s been shown to neutralize dozens of HIV strains in guinea pigs, monkeys, and mice by kick starting the immune response via HIV-fighting antibodies, according to a recent press release. Once a person is infected with HIV, the virus starts attacking immune cells that would normally protect the body from illness and infection. But, with this important new development, the new vaccine might prevent the disease from taking hold entirely, and that's major news.
The findings were reported yesterday in the Nature Medicine journal by researchers at the National Institute of Allergy and Infectious Diseases (NIAID) and the National Institutes of Health. The press release further states that the vaccine introduces antibodies which target a vulnerable site on the virus, potentially neutralizing infection.
"This elegant study is a potentially important step forward in the ongoing quest to develop a safe and effective HIV vaccine,” NIAID director Anthony S. Fauci MD said in the press release. He also says that “NIH scientists have used their detailed knowledge of the structure of HIV to find an unusual site of vulnerability on the virus and design a novel and potentially powerful vaccine.”
There's no doubt that health outcomes and quality of life for the nearly 37 million people who live with HIV/AIDS globally have improved over the years, thanks to prophylactic treatment options like PReP, but researchers haven't come up with a vaccine yet. If the new vaccine proves consistently effective, though, it will be the first to protect people from contracting HIV in the first place, according to Axios.
According to a recent press release, researchers examined an epitope — which is the site on an antigen (a toxic or foreign substance) which antibodies bind to — called the HIV fusion peptide. The HIV virus uses this peptide to bind to the cells it enters into and infects. The HIV fusion peptide was chosen because its structure is similar across multiple HIV strains, and researchers found that immune responses during testing were reacted strongly to it. The research team also designed a bunch of different immunogens — which are proteins designed to activate the immune response — in order to make the vaccine, and then tested it on mice to see which immunogens most effectively produced antibodies and a strong immune response. They found that the best vaccine combination consisted of eight amino acids of the HIV epitope bonded to a carrier that elicited a super robust immune reaction. The research team then tested different combinations of injections on mice, and analyzed the various immune responses in order to see which shot produced the strongest one.
The press release also reports that scientists are now working to refine the vaccine regimen to make it even more effective; they also aim for more consistent results with fewer injections. So far, the experimental vaccine neutralized up to 31 percent of viruses from a “globally representative panel of 208 HIV strains,” according to the press release, and was further tested on monkeys and guinea pigs. Researchers are further investigating vaccine development for use in preventing HIV in monkeys, and, so far, it looks like the current combination may be effective in multiple species. NIAID researchers hope to use these findings to optimize the new vaccine’s effectiveness, and then create a version suitable for testing in human volunteers in future clinical trials.
For now, the development of the new vaccine points to a potentially promising future — in which HIV prevention is possible. The research team hopes to start human clinical trials by mid-2019, and whatever those findings may show, the fact that it's at all possible is a major step forward in this research.