Scientists find rabies-based vaccine could be effective against HIV

Apr 03, 2007

Rabies, a relentless, ancient scourge, may hold a key to defeating another implacable foe: HIV. Scientists at Jefferson Medical College in Philadelphia have used a drastically weakened rabies virus to ferry HIV-related proteins into animals, in essence, vaccinating them against an AIDS-like disease. The early evidence shows that the vaccine – which doesn’t protect against infection – prevents development of disease.

Reporting April 1, 2007 in the Journal of Infectious Diseases, the scientists showed that two years after the initial vaccination, four vaccinated non-human primates were protected from disease, even after being "challenged" with a dangerous animal-human virus. Two control animals developed an AIDS-like disease.

Matthias Schnell, Ph.D., professor of microbiology and immunology at Jefferson Medical College of Thomas Jefferson University, and his co-workers tested the effects of inserting two different viral proteins into the rabies virus genome, and using such viruses-based vaccines in preventing disease in rhesus macaques. One was a glycoprotein on the surface of HIV, while the other was an internal protein from simian immunodeficiency virus (SIV). They used the latter because HIV does not cause disease in monkeys.

The idea was that such rabies’ vehicles, or "vectors," would help attract a strong response from the animal’s immune system, though the rabies virus used cannot cause disease. Such vectors are based on a type of rabies vaccine strain that has been used for more than 20 years in oral vaccines against rabies in wildlife in Europe. The study was aimed at studying the safety and effectiveness of the rabies vaccine approach against HIV and related diseases.

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?

Source: Thomas Jefferson University

Explore further: So much has changed since the first HIV test was approved 30 years ago

add to favorites email to friend print save as pdf

Related Stories

Vaccines from a reactor

21 hours ago

In the event of an impending global flu pandemic, vaccine production could quickly reach its limits, as flu vaccines are still largely produced in embryonated chicken eggs. Udo Reichl, Director at the Max ...

Lighting up a new path for novel synthetic polio vaccine

Feb 13, 2015

Scientists from the UK and US are using technology that helped in the design of a new synthetic vaccine to combat the foot and mouth disease virus (FMDV) to now target the virus that causes polio. The synthetic ...

Recommended for you

Preventing one case of HIV saves over $225K, study shows

Feb 27, 2015

How much money would be saved if one high-risk person was prevented from contracting HIV in the United States? A new study led by a researcher at Weill Cornell Medical College and published online Feb. 24 in Medical Care, answer ...

Research captures transient details of HIV genome packaging

Feb 27, 2015

Once HIV-1 has hijacked a host cell to make copies of its own RNA genome and viral proteins, it must assemble these components into new virus particles. The orchestration of this intricate assembly process falls to a viral ...

Could an HIV drug beat strep throat, flesh-eating bacteria?

Feb 25, 2015

With antibiotic resistance on the rise, scientists are looking for innovative ways to combat bacterial infections. The pathogen that causes conditions from strep throat to flesh-eating disease is among them, but scientists ...

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.