Meningococcal group C capsular polysaccharide (None (no widely used abbreviation; sometimes "MenC CPS" in literature, but not standardized[2]))

Meningococcal group C capsular polysaccharide is a homopolymer made of α(2→9)-linked sialic acid (N-acetylneuraminic acid) units, forming a thick carbohydrate capsule on the surface of Neisseria meningitidis serogroup C. Capsular expression is essential for systemic invasive disease, facilitating immune evasion and pathogenicity. The molecule is the principal target in serogroup C-specific meningococcal vaccines: plain polysaccharide vaccines act through T-cell independent mechanisms, but conjugate vaccines covalently link the polysaccharide to protein carriers, greatly improving immune response and memory, especially in children[1][2]. Monitoring antibody titers against this polysaccharide is used to evaluate vaccine efficacy. The capsule also plays a role in bacterial resistance to environmental stress and attachment during colonization. The molecular genetics of capsule biosynthesis and transport are encoded in the cps (capsular polysaccharide synthesis) locus of Neisseria meningitidis, with serogroup-specific differences[1][2]. Structural alterations of the capsule (acetylation, loss, switching) can impact vaccine efficacy and diagnostic detection[1]. The capsule is not a receptor, enzyme, or transporter; it is a carbohydrate-based vaccine antigen classified as a bacterial capsular polysaccharide[1][2].

Other names

MenC capsular polysaccharideNeisseria meningitidis serogroup C polysaccharideGroup C meningococcal polysaccharideMenC CPS

Vaccines: Antibodies induced against the capsular polysaccharide bind to the capsule, neutralizing or opsonizing bacteria for killing and clearance[2]. Conjugate vaccines enhance immunological memory and boost response compared to polysaccharide-only vaccines.