To block infection from HIV, a successful vaccine will require a combination of ingredients, including at least three antibody targets and a substance that boosts immune responses.
In a step toward achieving that goal, one potential vaccine component has led to strong protection in primates by eliciting an antibody that binds to part of the virus’s outer envelope, reports a team led by researchers at the Duke Human Vaccine Institute (DHVI).
“This is significant progress toward a viable HIV vaccine,” said Barton Haynes, M.D., director of the DHVI and senior author of the study appearing online this week in the journal Science Translational Medicine. “While we know this will be a many-step process, each step is an advancement toward our goal.”
Haynes and colleagues, including first author Kevin Saunders, Ph.D., director of research at at DHVI, isolated neutralizing antibodies that arose from a person living with HIV.
These antibodies bind to a known site on the virus that is conserved among many HIV strains. Exploiting this interaction, the researchers built an immunogen that stimulates the protective neutralizing antibodies against the immunizing strain.
Along with the immunogen, the researchers tested potential adjuvants, which boost the immune response. The team found that the best adjuvant ingredient was a Toll-like receptor called TLR7/8 that is a common ingredient in other vaccines.
Together, the protein and adjuvant in the vaccine provided protection from infection.
“Our study supports the notion that relatively high levels of multiple broadly neutralizing antibody types will need to be induced by vaccination to prevent HIV infection,” Haynes said. ”Our study also suggests that the use of the TLR7/8 agonist was key for inducing high concentrations of neutralizing antibodies and potently activating the immune system.” (AP/Newswise)