Antibacterial and antifungal vaccines based on synthetic oligosaccharides - Carbohydrate Chemistry: Chemical and Biological Approaches - page 583

4.2 Clostridium dicile
C. dicile is also the cause of emerging nosocomial infections that result
in abundant morbidity and mortality worldwide. 149 The glycans Poly-
saccharide I (PSI) and Polysaccharide II (PSII) were recently identified on
the bacterial surface, and are promising vaccine candidates to prevent C.
dicile infections. 150 PSI 41 and PSII 42 have a phosphorylated hexa- and
pentasaccharide repeating unit, respectively (Scheme 14).
The synthesis of the spacer-armed hexasaccharide was reported by two
groups 151,152 as well as the synthesis of phosphorylated hexasaccharide.
Conjugates of synthetic oligosaccharides to CRM 197 elicit a strong immune
response. Most notably, 153 the immune response in mice to phosphoryl-
ated hexasaccharide 43 was comparable to that for native PSII.
Similarly, the synthesis of a pentasaccharide corresponding to 41 154
and of their CRM 197 -conjugates was accomplished. Mice produce anti-
bodies against PSI after immunization with pentasaccharide-CRM 197 .
The disaccharide Rha-(1 3)-Glc was identified by a glycan array as the

minimal epitope recognized by the antibodies.
Judging on the speed of this work, the identification and evaluation of
a vaccine candidate against C. dicile could be expected soon.

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4.3 Bacillus anthracis
B. anthracis is a spore-forming bacterium that causes anthrax in humans
and in other mammals. 155,156 A major constituent of the outer surface

Scheme 14