A new HIV vaccine developed by La Jolla Institute for Immunology (LJI), Scripps Research scientists, and the International AIDS Vaccine Initiative, has the potential to protect humans from developing HIV infection and AIDS.
This HIV vaccine is the first to generate a high number of ‘broadly neutralising’ virus-fighting antibodies in primates. This groundbreaking research, published in Nature, is the result of 14 years of collaboration between La Jolla Institute for Immunology and Scripps Research, as part of the Scripps Consortium for HIV/AIDS Vaccine Development (CHAVD).
The new vaccine works by intervening in a process called B cell maturation. HIV is hard to beat because it doesn’t give B cells a chance to develop effective antibodies. The first problem is that HIV disguises itself from the immune system. The virus is wrapped in an ever-shifting cloak of sugar molecules, called glycans. The second big problem is that HIV mutates very quickly, while the third problem is that HIV changes its shape when it infects human cells. Taken together, these problems rarely give B cells a chance to hone their antibody responses against HIV. Even if a B cell manages to make neutralising antibodies, the virus can mutate or change its shape, rendering those antibodies useless.
The LJI and Scripps Research teams spent years hunting for ‘broadly neutralising’ antibodies that can actually bind to HIV and recognise key viral structures, even if the rest of the virus mutates. These antibodies are very, very rare, but they can be found in blood samples from a small number of people living with HIV. An effective HIV vaccine would need to prompt the immune system to make these same broadly neutralising antibodies.
The scientists studied what made the HIV-fighting B cells special. Then they reversed the process to see exactly how those B cells matured. By looking back at the maturation process, the researchers could track how the B cells changed when they saw specific pieces of the HIV structure. The team discovered that B cells matured to make broadly neutralising antibodies after they got an early look at parts of HIV’s outer ‘envelope’ protein. Because these viral sites sparked an immune response, scientists would call them antigens.
An effective HIV vaccine would likely need to include models of these antigens. If B cells saw those antigens early and often, they would get really good at recognizing and even neutralising HIV. The Schief Lab developed vaccine molecules that resembled the real HIV antigens. The scientists then worked with Emory National Primate Research Center, to test this potential HIV vaccine rhesus macaque primates.
The scientists found that around 44% of the animals went on to produce broadly neutralising antibodies against HIV in their blood. These antibodies were impressively abundant. The team didn’t test whether these antibodies could prevent infection, but it’s significant that these antibodies could be found in the blood, where they could encounter and potentially block HIV.
The Crotty Lab plans to investigate how it might change the booster shot regimen to make the HIV vaccine even more effective. Importantly, the antibodies found in the animal subjects resembled the exact kinds of broadly neutralising antibodies seen in those rare humans who made their own. It’s clear that our immune systems can make these powerful antibodies, given the right training.
- Steichen JM, Madden PJ, Flynn CT, et al. Vaccination elicits HIV broadly neutralizing antibodies in primates. Nature. 2026 Jun 30. doi:10.1038/s41586-026-10837-5 Online ahead of print.