A new HIV vaccine developed by La Jolla Institute for Immunology, Scripps Research scientists, and IAVI has shown the ability to generate a high number of broadly neutralizing virus-fighting antibodies in primates, according to a July 6 announcement. The research team said this is the first time such an outcome has been achieved with an HIV vaccine candidate.
"This feels like a huge success," said Shane Crotty, Professor and Chief Scientific Officer at La Jolla Institute for Immunology, who co-led the research with Scripps Research Professor William Schief. "We constructed a successful vaccine from the ground up, which required a deep understanding of the immune system."
The study was published in Nature and is based on 14 years of collaboration between La Jolla Institute for Immunology and Scripps Research as part of the Scripps Consortium for HIV/AIDS Vaccine Development. Crotty described it as "one of those Apollo moon mission-type projects, where there is an exceptional goal and the team has to accomplish a myriad of discoveries and inventions along the way." The new vaccine works by targeting B cell maturation—a process where immune cells develop their ability to produce antibodies that can bind to pathogens.
Researchers identified that B cells matured into producing broadly neutralizing antibodies after early exposure to specific parts of HIV's outer envelope protein. By designing antigens that mimic these viral sites, scientists aimed to train B cells effectively through vaccination. In tests involving rhesus macaques at Emory National Primate Research Center, about 44 percent of animals produced broadly neutralizing antibodies following a series of priming and booster shots designed using this approach.
Patrick Madden, Instructor at La Jolla Institute for Immunology and co-first author on the study with Jon Steichen from Scripps Research, explained: "This series of vaccinations will guide, or 'walk,' a B cell from its naive state to its broadly neutralizing state." Madden also noted that while infection prevention was not tested directly in this study, finding these antibodies present in blood indicates potential effectiveness against HIV.
The researchers plan further studies on optimizing booster regimens with hopes for higher response rates among subjects. Crotty said, "We believe this vaccine approach is even more likely to succeed in humans because of the immunogenetics." Human trials are underway or planned using similar immunogens evaluated previously.
