Fighting Hospital Germs With Sugar

Scientists develop synthetic sugar-based molecule as potential C. difficile vaccine

A vaccine against one of the most dangerous hospital germs may be available in the near future. Scientists in Germany have developed a substance that elicits an immune response against the gut bacterium Clostridium difficile. The potential vaccine resembles the sugar structures present on the surface of the bacterium and may therefore prime the immune system to recognize the pathogen itself.

The findings were published in the April 2016 issue of Nature Communications.

C. difficile infects a large proportion of patients in hospitals and kills approximately 15,000 people a year in the United States. Doctors treat the infection with antibiotics, but the bacterium mutates constantly, allowing it to escape the effects of pharmacotherapy. The discovery by researchers at the Max Planck Institute of Colloids and Interfaces may pave the way for developing new medications and vaccines against C. difficile.

The researchers first investigated which parts of the sugar coating on bacteria are necessary to trigger an immune response. They then constructed an artificial molecule with those properties by attaching the essential sugar structures to an amino-acid backbone. Coupled with an immunostimulating peptide, the molecule stimulated the immune systems in mice to produce antibodies that were effective against the similarly constructed surface sugars of C. difficile. The mice were thus protected against a subsequent infection with the bacterium. Moreover, the researchers say, it may be possible to use the molecule to produce therapeutic antibodies that can be administered to sick patients to boost their immune systems and combat infections.

Many bacteria bear characteristic carbohydrates on their surfaces, and it is known that these surface sugars are suitable for immunization purposes. However, the surface sugars usually have to be detached from specially bred microbes—an expensive and complicated process. By synthesizing artificial molecules for immunization, the German researchers have come up with a cost-effective alternative.

To progress from research results to clinical use in patients, the scientists are working to develop novel carbohydrate-based vaccines.

Source: Max Planck Institute of Colloids and Interfaces; May 11, 2016.