Neisseria meningitidis capsular polysaccharide group C (NmC-CPS)

Neisseria meningitidis capsular polysaccharide group C is a high-molecular-weight, linear homopolymer of sialic acid (N-acetylneuraminic acid) residues linked by α-(2→9) glycosidic bonds, sometimes partially O-acetylated. The group C polysaccharide forms the basis of serogroup C classification and is the critical virulence factor for Neisseria meningitidis, facilitating escape from host immune defenses by inhibiting complement-mediated killing and phagocytosis. This capsule is the antigenic component targeted by group C conjugate vaccines, which induce protective, bactericidal antibody responses and have been highly effective in preventing invasive meningococcal disease caused by serogroup C strains. The genes encoding biosynthesis and export of the capsule are clustered at a chromosomal locus designated cps, and changes in this locus enable capsule switching, a mechanism for immune evasion. Detection of the group C capsule is a crucial biomarker for diagnosis, epidemiological surveillance, and assessment of vaccine response.

Other names

Meningococcal group C capsular polysaccharideMenC polysaccharideGroup C polysialic acid capsuleNmC CPS

Induces protective antibodies targeting the capsule, promoting opsonization and clearance of bacteria. Blocks colonization and invasive disease by rendering the capsule antigenically recognizable to the immune system.