Promising HIV Vaccine used in Non-Human Primates

Researchers at the Scripps Research Institute have developed a vaccine which shows promise against a strain of HIV, considered a tier 2 virus because of its constantly changing conformation, that resembles the type found in humans. The vaccine stimulates the production of neutralizing antibodies that target a trimeric Env glycoprotein which exists mostly in a closed configuration. These neutralizing antibodies, when manufactured in the lab, were discovered to counteract the effects of the virus in animal models. The challenge posed to scientist however was inducing the animals to generate the antibodies in their own. This required them being exposed to the Env trimer, which was notoriously unstable. In 2013, however, a genetically engineered trimer was produced and researchers moved forward by generating a vaccine containing it. They then reimmunized multiple groups of rhesus macaque monkeys who had both low and high antibody levels, along with a group of unimmunized primates as a control. The primates were then injected with SHIV, engineered simian HIV, that displays the same Env trimer. Among those monkeys with high antibody levels (or titers), the vaccine prevented against infection, but titer levels eventually fell as did immunity. However, the study is one of the first of its kind to determine the level of antibodies needed to produce immunity. and researchers have now shifted their efforts to determine ways to maintain high neutralizing antibody levels. Further, they are also searching for broadly neutralizing antibodies (bnAbs) that can neutralize many strains of HIV, rather than the single strain that this vaccine targets.

Read more at: https://www.sciencedaily.com/releases/2018/12/181214121811.htm

-Riasoya Jodah