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AIDS vaccine efficient in monkey
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A TEAM of researchers have found that a multi-protein AIDS vaccine that combines a DNA "primer" with a modified smallpox virus "booster" can control a highly virulent HIV challenge in rhesus macaques.
Although the vaccine didn't prevent infection in the monkeys, it rapidly reduced their viral loads by encouraging a burst of antiviral T cells, said researchers in Friday's issue of Science magazine.
The vaccine system was designed and tested by scientists at the National Institutes of Health (NIH), Emory University in Atlanta, Georgia, and other research organizations.
The premier, or DNA part of the vaccine system, was injected first. It contains genes for three proteins like those found in the AIDS virus and helps stimulate the immune system to attack AIDS virus and keep monkeys healthy.
The booster, or the smallpox virus part of the vaccine, was injected 24 weeks later. This part is a safe modified smallpox virus with HIV and SIV genes, and it intensifies the immune system's response against the AIDS virus proteins. SIV is a virus that causes AIDS in monkeys.
Both parts of the vaccine encoded Gag, Pol and Env proteins, said Dr Harriet Robinson, professor of Emory University and the leading author of the Science paper.
Monkeys then received the viral challenge seven months later, said Dr Bernard Moss, researcher at the NIH and developer of the virus part of the vaccine system. The infection is similar to how most HIV-1 infections occur.
Moss told Xinhua that they used in the study a total of 28 healthy monkeys, 24 of which were vaccinated and the other four were injected with only placebos.
All the 28 monkeys were exposed to a high dose of the virus and all of them were infected. But in the face of the challenge, the 24 vaccinated monkeys remained healthy, with reduced viral loads and intact immune responses, while all the other four monkeys injected with a placebo developed AIDS and died within 28 weeks.
Moss said the amount of AIDS virus in inoculated monkeys decreased to almost undetectable levels one week later.(Xinhua)
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