Polysaccharide capsule of Neisseria meningitidis serogroup C

The polysaccharide capsule of Neisseria meningitidis serogroup C is a major surface-expressed carbohydrate polymer and the principal virulence factor of this pathogenic bacterium. It consists of a homopolymer of α-2-9-linked sialic acid (N-acetylneuraminic acid, Neu5Ac), often O-acetylated at the C7 or C8 position. The capsule enables the bacterium to evade host immune defenses, particularly by resisting complement-mediated lysis and phagocytosis, thereby enabling survival in the blood and other normally sterile sites. The serogroup C capsule forms the basis for serogroup classification and is targeted by effective polysaccharide-protein conjugate vaccines. Genetic determinants for capsule biosynthesis and export are clustered within the cps locus on the bacterial chromosome. Conjugate vaccines containing this capsular antigen effectively induce protective immunity and have significantly reduced the burden of serogroup C meningococcal disease worldwide.

Other names

Serogroup C capsuleNeisseria meningitidis serogroup C capsular polysaccharideSerogroup C polysaccharide capsule

Induction of anti-capsular antibodies, leading to complement-mediated bacterial killing