Vaccines protect monkeys against Marburg and Ebola viruses
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《英国医生杂志》
Canadian and US scientists have developed safe and effective vaccines that completely protect non-human primates against the often lethal Marburg and Ebola haemorrhagic fever viruses. "They have high potential for use in humans," said Steven Jones of the National Microbiology Laboratory of the Public Health Agency of Canada in Winnipeg. The study was published online in Nature Medicine on 5 June 2005 (www.nature.com/naturemedicine, doi: 10.1038/nm1258).
Two health workers leave the isolation area for patients with Marburg virus in a hospital in Luanda, Angola. Scientists in Canada think a new vaccine has potential in humans
Credit: FLORENCE PARNOUSSIAN/AFP/GETTY
Dr Jones and Heinz Feldmann of the Canadian group developed the live attenuated recombinant vaccine by replacing a surface protein in vesicular stomatitis virus, an animal pathogen, with a surface protein from either the Ebola or Marburg virus.
"A single injection produced completely protective immune responses. Monkeys get the same disease from these viruses that humans do, namely haemorrhagic fever. The mortality in humans is up to 90%," Dr Jones said.
No vaccines or treatments are approved for human use. The current Marburg outbreak in Angola has caused 355 deaths in 399 patients.
The Canadian scientists worked with mice and guinea pigs. They collaborated with Thomas Geisbert at the US Army Medical Research Institute of Infectious Diseases in Fort Detrick, Maryland, to test the vaccine in non-human primates.
Dr Geisbert's group injected six cynomolgus macaques with a single dose of the Ebola vaccine and another six monkeys with a single dose of the Marburg vaccine. None of the animals showed any signs of illness. Four weeks later, four animals in the Ebola vaccine group were challenged with an intramuscular dose of Ebola virus and remained well. The other two Ebola vaccinated animals were challenged with an intramuscular dose of Marburg virus and died.
A similar challenge in the animals immunised for the Marburg virus produced similar results.
Dr Geisbert said that the next steps were to "dose down" to find out how low a dose of the vaccine would protect. "We don't want to use any more than we have to, for safety issues and also for the cost of production," he explained. He also wanted to learn how soon animals were protected, perhaps as early as 10 to 14 days after immunisation. The faster that protection is achieved, the more useful it will be in protecting healthcare workers responding to an epidemic, he said.
Dr Geisbert said that one to two years of animal work were needed before the vaccine would be ready for phase I trials in humans.(Janice Hopkins Tanne)
Two health workers leave the isolation area for patients with Marburg virus in a hospital in Luanda, Angola. Scientists in Canada think a new vaccine has potential in humans
Credit: FLORENCE PARNOUSSIAN/AFP/GETTY
Dr Jones and Heinz Feldmann of the Canadian group developed the live attenuated recombinant vaccine by replacing a surface protein in vesicular stomatitis virus, an animal pathogen, with a surface protein from either the Ebola or Marburg virus.
"A single injection produced completely protective immune responses. Monkeys get the same disease from these viruses that humans do, namely haemorrhagic fever. The mortality in humans is up to 90%," Dr Jones said.
No vaccines or treatments are approved for human use. The current Marburg outbreak in Angola has caused 355 deaths in 399 patients.
The Canadian scientists worked with mice and guinea pigs. They collaborated with Thomas Geisbert at the US Army Medical Research Institute of Infectious Diseases in Fort Detrick, Maryland, to test the vaccine in non-human primates.
Dr Geisbert's group injected six cynomolgus macaques with a single dose of the Ebola vaccine and another six monkeys with a single dose of the Marburg vaccine. None of the animals showed any signs of illness. Four weeks later, four animals in the Ebola vaccine group were challenged with an intramuscular dose of Ebola virus and remained well. The other two Ebola vaccinated animals were challenged with an intramuscular dose of Marburg virus and died.
A similar challenge in the animals immunised for the Marburg virus produced similar results.
Dr Geisbert said that the next steps were to "dose down" to find out how low a dose of the vaccine would protect. "We don't want to use any more than we have to, for safety issues and also for the cost of production," he explained. He also wanted to learn how soon animals were protected, perhaps as early as 10 to 14 days after immunisation. The faster that protection is achieved, the more useful it will be in protecting healthcare workers responding to an epidemic, he said.
Dr Geisbert said that one to two years of animal work were needed before the vaccine would be ready for phase I trials in humans.(Janice Hopkins Tanne)