With own weapons
For weeks, a white powder terrified the American population: a few days after the attacks of September 11, 2001, four innocent people fell victim to letters containing the powder - spores of the anthrax pathogen. Recreation of a molecule characteristic of anthrax could be the basis for a new anthrax vaccine.
Bacillus anthracis spores cause a disease called anthrax or anthrax that affects herbivores such as cattle, sheep and goats. Humans rarely become infected unless the extremely resilient spores are specially prepared and used as a biological weapon. Anyone who inhales these spores will die within a few days. To be prepared for a threat, you need effective vaccines.
The first step in developing a vaccine is to find a suitable antigen. It is a molecule or part of a molecule that is characteristic of a pathogen and to which the immune system reacts by producing antibodies.
Like most bacteria, Bacillus anthracis also has specific oligosaccharides on the surface of its spores, i.e. polysaccharides that presumably play an important role in the interaction with the infested organism. Scientists elucidated the structure of such an oligosaccharide last year: the molecule consists of four sugar units. Of particular interest is one of the terminal sugars, called anthrose, which appears to be found exclusively on the surface of anthrax spores.
Peter Seeberger and Daniel Werz from ETH Zurich have now succeeded in replicating this quadruple sugar in a total synthesis for the first time. At the heart of this was a new, particularly effective synthesis route for the anthrose unit. The scientists also attached a kind of molecular hook to the artificially produced quadruple sugar, to which a transport protein that is necessary for successful immunization can later be coupled. They designed their entire synthetic route so flexibly that variants of the sugar molecule are also easily accessible.
"We are currently conducting immunological studies with the quadruple sugar," explains Seeberger. "In parallel, we are producing a series of derivatives of the sugar to also shed light on their potential as highly specific anthrax vaccines." © Angewandte Chemie