"Based on our results, we think it is likely that this vaccine could be an effective AIDS vaccine in humans," said principal investigator John K. Rose, professor of pathology and cell biology at Yale University School of Medicine.
For the past six years, Rose and his team have been developing a common livestock virus as a vaccine vector (a vaccine delivery system). This vector system, which is called VSV (vesicular stomatitis virus), was highly effective in animal models for influenza and measles. Published in the September 7 issue of Cell, the results of two new studies show that vaccination with the VSV vector encoding AIDS virus proteins can protect monkeys from AIDS caused by a virus that is a hybrid between a human AIDS virus and a monkey AIDS virus.
The research team first vaccinated seven monkeys with their new vaccine and then infected them with the AIDS virus. Eight control monkeys were also infected with the AIDS virus, but did not receive the vaccine. "We found that seven out of eight unvaccinated monkeys developed AIDS in an average of five months, while vaccinated monkeys have been AIDS-free for up to 14 months," said Rose.
Rose said that two other studies using DNA vaccine approaches published in Science in the past year demonstrated similar protection, but that those DNA vaccine vectors may not be as practical as VSV.
"An advantage of the VSV vector system over the others is that it does not require multiple injections and instead can be given as nasal drops," said Rose. "In the developing world and areas that have been hit hard with HIV and AIDS, it would be impractical and very expensive to inject millions of people with DNA vaccines. The VSV-based vaccine would be a cost-effective and equally successful alternative to the other vaccines that have been tested. We are truly excited about this advance."
Rose said the next step is to begin preparing for a Phase I safety trial in humans. He presented the most recent findings at the AIDS Vaccine 2001 Conference in Philadelphia on September 6.
Other authors on the study include first author Nina F. Rose, Linda Buonocore and Anjeanette Roberts of Yale; Preston A. Marx of the Aaron Diamond AIDS Research Center and Tulane University; Amara Luckay of the Aaron Diamond AIDS Research Center; Douglas F. Nixon, Walter J. Moretto and Sean M. Donahoe of the Gladstone Institute of Virology and Immunology and David Montefiori of Duke University.