Thanks to recent developments, scientists believe that they are one step closer to developing a vaccine against AIDS.
In the study, lead author Matthias J. Schnell, from Thomas Jefferson University, and colleagues found that a rabies virus-based vaccine administered to monkeys protected against the simian equivalent of the HIV virus (SIV).
The researchers previously showed that a rabies-based vaccine expressing HIV and SIV antigens protective against a chimeric HIV/SIV virus in monkeys.
In the new study, they used highly attenuated rabies virus vaccine vectors to protect against challenge with the highly pathogenic SIVmac251.
This type of SIV virus causes a more similar disease in monkeys compared to human infection with HIV-1. In addition, it is difficult to protect monkeys against AIDS-like disease after challenge with SIVmac251.
Two vaccine strategies were used: immunization with a recombinant rabies virus expressing SIVmac239GagPol, or a combination of that and a rabies virus expressing SIVmac239Env. Both strategies induced neutralizing antibody production, CD8+ T cell responses, and increased protection.
Although the combination with Env helped immediately following the infection, the long-term benefits were minimal. However, it was surprising that the rabies-based vaccine was able to induce such potent anti-SIV humoral responses.
"Although we can't yet block the infection, we showed that we can protect against disease. We also saw significant antibody activity against the virus, which is promising. In addition, this is a very simple approach that only took two immunizations," said Schnell.
The study was published in the journal Vaccine.