A new vaccine against the SARS coronavirus has shown promising results in early trials, researchers report in the December issue of 6 The Lancet . The vaccine revved up immune responses in six monkeys, but researchers have not yet tested its ability to fend off disease. No human vaccine exists yet.
To develop the vaccine, Andrea Gambotto and colleagues at the University of Pittsburgh have turned to adenovirus, the culprit behind the common cold. They were designed so that each three adenovirus expresses a component of the SARS virus of different proteins. The idea behind the vaccine is to stimulate a slight attack against the cold virus, and a fierce attack against the SARS protein. Make a vaccine with the only SARS protein was more expensive and took longer, said Gambotto. And it would not have triggered the production of both T cells and antibodies -. Two components of the immune system attack considered necessary to protect
To see if the vaccine could trigger an immune response, the team injected six macaques with adenoviruses and gave them a booster injection 28 days later. After 6 weeks, all monkeys had mobilized killer T cells against SARS and had high levels of protective antibodies. Two control monkeys injected with a common cold virus, do not mount an attack. Because the monkeys do not develop SARS, the monkeys are not infected with the virus.
It is a first step, but significant, says Gary Nabel, director of the research center on vaccines at the National Institute of Allergy and Infectious Diseases (NIAID), which earlier this year suggested ' use adenoviral vaccines against SARS. Get the immune response to two components is important, says Nabel. "If you have one but not the other, the protection that you see tends to be shorter," he said.
Although the team Gambotto is the first to publish results against SARS vaccine trials, the list of candidate vaccines is booming. Nabel said it is too early to say which is best. A Canadian team working on another adenovirus vaccine and Chinese researchers can begin human studies using an inactivated virus in a few months, Nabel said, adding that his group hopes to begin human trials later next year with an adenovirus vaccine which protects mice against SARS infection.
related sites
basic information on SARS NIAID
SARS Resources Centers for Disease Control and Prevention
the site Gambotto
Vaccine Research NIAID Center of
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