Neisseria meningitidis serogroup B capsular polysaccharide (MenB CPS) (MenB CPS)

The Neisseria meningitidis serogroup B capsular polysaccharide is a homopolymer of alpha(2-8)-linked N-acetylneuraminic acid, commonly referred to as polysialic acid. It functions as a major virulence factor by shielding the bacterium from host immune responses, specifically by preventing complement-mediated killing and phagocytosis (Finne et al., 1983). This polysaccharide is unique among meningococcal serogroups because it is chemically and structurally identical to the polysialic acid found on the human neural cell adhesion molecule (NCAM) (Harrison, 2006). Due to this molecular mimicry, the human immune system typically recognizes the MenB capsule as a self-antigen, resulting in profound immune tolerance and poor immunogenicity for traditional vaccine approaches. This similarity also presents a significant safety concern, as antibodies targeting the native polysaccharide could theoretically cross-react with human neural tissues, potentially leading to autoimmune complications (Borkowski et al., 2012). Consequently, while other meningococcal vaccines target the capsule, approved MenB vaccines focus on surface proteins, though experimental strategies continue to explore modified polysaccharides like N-propionylated derivatives (Moe et al., 2002).

Other names

alpha(2-8)-linked polysialic acidGroup B meningococcal polysaccharideMenB capsulePolysialic acid

Induction of bactericidal antibodies that recognize the capsular polysaccharide, leading to complement-mediated lysis and opsonophagocytosis of the bacteria.