A team of chemists from Birmingham University has succeeded in making a completely synthetic vaccine. The vaccine, which contains no biologically derived components, could represent the first stage in the development of a new generation 'minimalist' vaccines with potentially fewer side-effects than their conventional counterparts.
The work, carried out by a team led by Dr Geert-Jan Boons, is part- funded by the Engineering and Physical Sciences Research Council.
While synthetic vaccines are unlikely to become available for several years, the research has demonstrated that it should be feasible to build, step by step, a system that mimics conventional vaccines.
When the body is invaded by a pathogen, antibodies recognise specific molecules on the surface of the pathogen - termed 'epitopes' - and trigger the immune response.
Vaccination involves triggering the immune response in the absence of a genuine infection, thereby 'arming' the body for the real thing.
The first vaccines used whole cells of pathogens that had been killed or 'crippled'.
Subsequent refinement of vaccines involved attempting to isolate only that part of the organism's surface that contained the relevant epitope. However, such vaccines can still incorporate extraneous material that is unnecessary for the immune response and which can cause complications.
The Birmingham team approached the problem from a different angle. Epitopes are often oligosaccharides - molecules made up of a small number of sugar sub-units. By studying the human pathogen Neisseria meningiditis, the team focused on the crucial portion of the epitope.
Synthesising the epitope in the laboratory was difficult. Not only did the specific sugar sub-units need to be arranged correctly in relation to one another, but the molecule's three-dimensional conformation in space needed to be precise. Using computer models coupled with complex synthetic chemistry techniques, the team succeeded re-creating the epitope. This was then attached to a synthetic peptide and a lipid - two other essential components of a vaccine.
"Realistically I do not think we will see this kind of vaccine in this century," says Dr Boons. "But if we can improve our synthetic methodology I think this will be the new generation of vaccines."
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Contacts:
Dr Boons.
Tel: 0121 414 4460
fax: 0121 414 4403
e-mail:
gjboons@chemistry.bham.ac.uk
Frank Albrighton, external relations director.
Tel: 0121 414 6679
fax: 0121 414
3984
e-mail: f.c.albrighton@bham.ac.uk