New Prime-Boost Strategy Shows Promise In Monkeys.(Brief Article)

2001 MAR 21 - (NewsRx.com & NewsRx.net) --

A team of academic and government researchers in the United States has reported on a promising new "prime-boost" HIV vaccine approach that is currently on a development fast-track for human clinical trials.

This vaccination strategy kept an HIV-like virus in check in monkeys, even when the animals were exposed to very high virus doses months after immunization. The study appeared March 9, 2001, in Science Express, an online publication of the journal Science.

The study indicates that the vaccine, composed of two DNA priming vaccines followed by a modified poxvirus booster, successfully primes the immune system's "memory" and provokes a strong immune response. This relatively simple vaccine regimen has achieved better protection than any other HIV vaccine candidate to date, placing this vaccine among the most promising candidates moving toward human clinical trials.

"We think the expression of multiple proteins was critical to the success of our vaccine," said study director and lead author Harriet Robinson, PhD, chief of the division of microbiology and immunology at Emory University's Yerkes Regional Primate Research Center, Atlanta, Georgia, and a faculty member of the Emory Vaccine Center.

"We have been really excited about the level of control we have achieved with our memory response," said Robinson. "Even among the groups that received the low-dose vaccine, the infections were controlled."

Scientists from Emory University and the U.S. National Institute of Allergy and Infectious Diseases (NIAID) combined two vaccines in a strategy they hoped might be effective and then evaluated that strategy in monkeys. Both vaccines were designed against SHIV, a virus containing components of HIV and the related monkey virus, simian immunodeficiency virus (SIV). SHIV mimics HIV infection and causes serious illness in macaque monkeys. The hybrid virus allows researchers to study the reactions of the immune system to the vaccines and the virus.