Neisseria meningitidis capsular group C polysaccharide (NmC polysaccharide)

The Neisseria meningitidis capsular group C polysaccharide is a homopolymer of α-2-9-linked N-acetylneuraminic acid (sialic acid, Neu5Ac) that forms a dense capsule around the surface of Neisseria meningitidis serogroup C bacteria. This capsule imparts serum resistance to the bacterium, making it a critical determinant of virulence and facilitating survival in the bloodstream and evasion of complement-mediated killing. The group C capsule is structurally distinct from other serogroups and is acetylated at specific positions on the sialic acid monomer. Capsules are classified genetically and biochemically, and the MenC capsule forms the basis of several successful conjugate vaccines, which are essential for the prevention of invasive meningococcal disease such as meningitis and septicemia. Genes responsible for its biosynthesis and export are grouped at the cps locus, with region A encoding the serogroup-specific synthetic enzymes.

Other names

MenC polysaccharideSerogroup C capsuleNmC capsuleGroup C capsular polysaccharide

Induction of protective anti-capsular antibodies (vaccines present NmC polysaccharide conjugated to carrier proteins to induce T-cell dependent immunity and immunological memory, neutralizing the bacterium and preventing infection)