N-Propionylation

Serogroup B Neisseria meningitidis remains a major world health problem and currently there is no fully efficacious vaccine available. The poor immunogenicity of the group B meningococcal polysaccharide both in adults and infants prevents the formulation of a comprehensive polysaccharide-based vaccine ( 1 ). Although, as discussed in Chapter 4 , conjugation technology can overcome the limitation of the poor immunogenicity of most capsular polysaccharides, the serogroup B meningococcal polysaccharide when conjugated to a protein carrier still failed to give a significant immune response ( 2 , 3 ). This phenomenon is probably attributed to the molecular mimicry between the polysaccharide and human-tissue antigens. As shown in Fig. 1 , the serogroup B polysaccharide is a homopolymer of α(2–8)-linked sialic-acid residues ( 4 ) and similar structures have also been identified in the humantissue antigens, from short trimeric fragments found in mammalian gangliosides ( 5 ) to long decameric fragments observed in the glycoproteins of neural-cell adhesion molecules (N-CAMs) ( 6 ). Fig. 1.  Chemical structure of GBMP.