Jefferson scientists find rabies-based vaccine could be effective against HIV

Four macaques were immunized with both vaccines, while two animals received only a weakened rabies virus. After they gave the animals an initial vaccination, they then tried two different immune system boosts, but didn’t see enhanced immune responses. They then developed a new vector, a viral surface protein from another virus, vesicular stomatitis virus (VSV). Two years after the initial immunization, they gave a booster vaccine with the rabies-VSV vector, and saw SIV/HIV-specific immune responses.

The group then challenged the animals with SIV and measured various parameters of infection, such as immune system CD4 cell count, amount of virus in the bloodstream and immune system antibody response. They found that those animals that were given the test vaccine could control the infection. The control animals without the experimental vaccine had high levels of virus and a loss of CD4 cells.

"We still need a vaccine that protects from HIV infection, but protecting against developing disease can be a very important step," Dr. Schnell says, noting that he and his colleagues aren’t sure how long the viral immunity will last.

According to Dr. Schnell, the study demonstrated a "proof of principle" – that is, that the method used is technically possible. He says that the results indicate the need for future studies in larger groups of animals, and that these currently are underway. In addition, one key question remains unanswered: Is such a rabies-based vaccine feasible as an HIV vaccine in humans?

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