An HIV vaccine may be on the horizon as a trial conducted by researchers from Duke University led to stimulation of antibody which may well help protect people against the deadly disease.
Since its identification in 1983, HIV has ravaged communities worldwide, infecting over 85 million people and claiming the lives of approximately 40 million individuals.
While pre-exposure prophylaxis (PrEP) has been effective in reducing the risk of HIV transmission, its reliance on daily intake poses challenges.
In a clinical trial that began in 2019 at Duke University, an experimental vaccine stimulated the production of a crucial type of broadly neutralising antibody in a small group of participants.
The results were published on Friday in the scientific journal, Cell.
"This is one of the most pivotal studies in the HIV vaccine field to date," said Glenda Gray, an HIV expert and the president and CEO of the South African Medical Research Council, who was not involved in the study.
"This is a scientific feat and gives the field great hope that one can construct an HIV vaccine regimen that directs the immune response along a path that is required for protection," Gray told Wired.
A few years ago, researchers from Scripps Research and the International AIDS Vaccine Initiative (IAVI), demonstrated the possibility of stimulating precursor cells required to produce rare antibodies in individuals. Building on it, the recent Duke University study took a step forward in generating these antibodies, at lower levels.
Vaccines function by training the immune system to identify and combat viruses or other pathogens. They accomplish this by introducing a component resembling the virus, such as a fragment or a weakened form.
This triggers the body's B cells to produce protective antibodies against the simulated virus. These antibodies persist, ensuring that when the individual encounters the actual virus later on, their immune system recognizes it and mounts a defence.
Developing a vaccine against HIV has posed considerable challenges due to the distinctive characteristics of the virus. HIV mutates rapidly, allowing it to evade immune responses effectively. Additionally, it integrates into the human genome shortly after exposure, evading detection by the immune system.
"Parts of the virus look like our own cells, and we don’t like to make antibodies against our own selves," says Barton Haynes, director of the Duke Human Vaccine Institute and one of the authors on the paper.
Haynes and his team developed a vaccine that uses synthetic molecules mimicking a part of HIV's outer coat, known as the membrane proximal external region. This region remains stable despite the virus mutating.
The trial was conducted with 20 healthy HIV-negative individuals.
Of them, 15 received two out of the planned four doses of the experimental vaccine, while five received three doses.
Researchers discovered that even two doses of the vaccine were adequate to prompt the production of low levels of broadly neutralising antibodies within a few weeks.
Testing the antibodies on HIV samples in the laboratory revealed their capability to neutralise between 15 and 35 per cent of them.
Jeffrey Laurence, a scientific consultant at the Foundation for AIDS Research (amfAR) and a professor of medicine at Weill Cornell Medical College, termed the findings a step forward.
"It outlines a path for vaccine development, but there’s a lot of work that needs to be done," he said.
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