US boffins make breakthrough in anthrax vaccine
http://www.zeenews.com/znnew/articles.asp?aid=389821&ssid=28&ssname=Health%20and%20Medicine&sid=ENV&sname=
London, Aug 19: Researchers at the University of Michigan in Ann Arbor, US have made a breakthrough in anthrax vaccination, which they claim, offers better protection than the standard vaccine currently in use, which involves six injections over 18 months followed by annual boosters.
For preparing the vaccine, the researchers used an antigen derived from Bacillus anthracis, the bacterium that causes anthrax. The antigen doesn't cause sickness itself, but provokes a protective immune response.
However, instead of injecting the antigen, the researchers mixed it with a soybean oil emulsion that had been formulated into droplets only 400 nanometres in diameter.
The nanoemulsion carries the droplets into the nasal passages, where they are detected by the immune system.
"This is similar to formulations designed to penetrate the skin that were developed by the cosmetics industry. It penetrates through the pores of the mucosa. When the antigen is applied to the nose without the emulsion it causes little or no immune response," said James R. Baker Jr, an immunologist on the team that carried out the work.
To test the new vaccine, the researchers dosed mice and guinea pigs, and later exposed them to anthrax spores, either inhaled or on the skin.
The scientists found that the guinea pigs were completely protected against exposure to the skin even when the dose was a thousand times greater than the normal lethal dose.
However, the protection was not as great for inhaled anthrax. An exposure of 10 times the lethal dose killed 30 percent of the guinea pigs, and 100 times the lethal dose killed 60 percent.
According to the research team, this is about the same level of effectiveness as offered by conventional anthrax vaccines, which were developed 30 years ago.
Nevertheless, the vaccine did extend survival time by between three and five days, which, scientists believe, might allow enough time in humans for other treatments to work.
London, Aug 19: Researchers at the University of Michigan in Ann Arbor, US have made a breakthrough in anthrax vaccination, which they claim, offers better protection than the standard vaccine currently in use, which involves six injections over 18 months followed by annual boosters.
For preparing the vaccine, the researchers used an antigen derived from Bacillus anthracis, the bacterium that causes anthrax. The antigen doesn't cause sickness itself, but provokes a protective immune response.
However, instead of injecting the antigen, the researchers mixed it with a soybean oil emulsion that had been formulated into droplets only 400 nanometres in diameter.
The nanoemulsion carries the droplets into the nasal passages, where they are detected by the immune system.
"This is similar to formulations designed to penetrate the skin that were developed by the cosmetics industry. It penetrates through the pores of the mucosa. When the antigen is applied to the nose without the emulsion it causes little or no immune response," said James R. Baker Jr, an immunologist on the team that carried out the work.
To test the new vaccine, the researchers dosed mice and guinea pigs, and later exposed them to anthrax spores, either inhaled or on the skin.
The scientists found that the guinea pigs were completely protected against exposure to the skin even when the dose was a thousand times greater than the normal lethal dose.
However, the protection was not as great for inhaled anthrax. An exposure of 10 times the lethal dose killed 30 percent of the guinea pigs, and 100 times the lethal dose killed 60 percent.
According to the research team, this is about the same level of effectiveness as offered by conventional anthrax vaccines, which were developed 30 years ago.
Nevertheless, the vaccine did extend survival time by between three and five days, which, scientists believe, might allow enough time in humans for other treatments to work.
