Neisseria meningitidis Capsular Polysaccharides (Serogroups A, C, W, Y)

Neisseria meningitidis is a Gram-negative bacterium that causes invasive diseases such as meningitis and septicemia. Its primary virulence factor is the polysaccharide capsule that surrounds the bacterial cell. The structure of this capsule determines the serogroup classification of N. meningitidis; there are 13 described serogroups, but serogroups A, C, W (formerly W-135), and Y are among those most commonly associated with human disease. Each serogroup's capsular polysaccharide has a distinct chemical composition: Serogroup A: Capsule composed of repeating units of O-acetylated (α1→6)-linked N-acetyl-D-mannosamine-1-phosphate. Serogroup C: Capsule made up of sialic acid homopolymers with (2→9) linkages. Serogroup W: Capsule consists of alternating units of D-galactose and sialic acid. Serogroup Y: Capsule contains alternating units of D-glucose and sialic acid. These structural differences form the basis for immunological distinction between serogroups.

Induction of protective antibody responses