Neisseria meningitidis serogroup W capsular polysaccharide antigen (MenW CPS)

The **Neisseria meningitidis serogroup W capsular polysaccharide antigen** is a surface-exposed, high-molecular-weight polysaccharide composed of alternating units of sialic acid (N-acetylneuraminic acid, Neu5Ac) and galactose, joined by α-(2→6) and α-(1→4) linkages[2][3][4][5]. The capsule acts as the principal virulence factor, allowing the bacterium to evade complement-mediated killing and phagocytosis[3][6]. It forms the basis for serological classification of meningococcal isolates and is the target of quadrivalent conjugate vaccines used to prevent invasive meningococcal disease. In serogroup W, the unique chemical structure of the capsular polysaccharide confers distinctive antigenic properties enabling focused immunological targeting[2][3][4][5].

Other names

Neisseria meningitidis serogroup W-135 capsular polysaccharideMenW polysaccharideW-135 antigenGroup W polysaccharide capsuleNm serogroup W capsule

Conjugate vaccine-induced immunity: Vaccines presenting the capsule polysaccharide (often conjugated to carrier proteins like tetanus or diphtheria toxoid) elicit bactericidal antibodies facilitating complement-mediated killing and opsonization of the bacterium