A promising candidate for a HIV vaccine may protect against dozens of strains of the virus and is almost ready for human testing, scientists say.
The vaccine creates antibodies that attack a vulnerable site of the virus discovered two years ago, according to researchers at the US National Institute of Allergy and Infectious Diseases (NIAID) and the National Institutes of Health (NIH) whose findings were published in the journal Nature Medicine earlier this month.
Researchers found naturally occurring antibodies can prevent multiple HIV strains from infecting human cells, but only half of all people living with HIV make the antibodies and only do so after several years.
The vulnerable sites on HIV where these antibodies bind to prevent the virus are called epitopes.
For this research, the scientists looked at an epitope called the HIV fusion peptide, a short string of amino acids on the surface of the “spikes” that the HIV virus uses to bind to the cells it infects, The Advocate reported.
The researchers created several different immunogens, which are proteins that get the immune system to respond, in order to develop the experimental vaccine.
Using antibodies known to target the fusion peptide epitope, the scientists studied which immunogens most successfully sent antibodies to the epitope.
The researchers tested several combinations of the injection on mice, guinea pigs and monkeys and looked at how the antibodies worked.
The antibodies in the most successful immunogen attached to the fusion peptide epitope and neutralized as many as 31 percent of 208 HIV strains from around the world.
Scientists have struggled for decades to create a HIV vaccine that effectively combats the virus’ diversity and ability to rapidly mutate.
The researchers hope to begin preliminary human trials of the new experimental vaccine regimen in the second half of 2019.
“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,” NIAID Director Dr Anthony Fauci said in a statement.
“This elegant study is a potentially important step forward in the ongoing quest to develop a safe and effective HIV vaccine.”