Neisseria meningitidis capsular polysaccharide (Serogroups C, W, Y) (MenC/W/Y)

Neisseria meningitidis capsular polysaccharides for serogroups C, W, and Y are essential virulence factors that form the outermost layer of the bacterium, protecting it from host immune defenses such as complement-mediated lysis and phagocytosis (Harrison et al., 2009). These polysaccharides are complex carbohydrates; serogroup C is a homopolymer of sialic acid, while serogroups W and Y are heteropolymers containing sialic acid and either galactose or glucose (PubChem). In the context of vaccinology, these polysaccharides serve as the primary antigens for MenACWY vaccines, which are often conjugated to carrier proteins to enhance immunogenicity (CDC, 2022). When administered, these vaccines induce the production of high-affinity, vaccine-induced antibodies that recognize the capsular antigens. These antibodies provide protection by activating the classical complement pathway and promoting opsonophagocytosis, thereby preventing invasive meningococcal diseases such as meningitis and septicemia (WHO, 2023). The presence of these antibodies, measured via serum bactericidal assays, is the established correlate of protection against the disease (FDA, 2020).

Other names

Meningococcal group C, W, and Y polysaccharidesMenC/W/Y antigensNeisseria meningitidis serogroup C/W/Y capsular antigensMeningococcal capsular polysaccharide C/W/Y

Vaccines containing these polysaccharides induce the production of specific IgG and IgM antibodies. These vaccine-induced antibodies bind to the bacterial capsule, facilitating complement-mediated bactericidal activity and opsonophagocytosis, which are the primary mechanisms for clearing Neisseria meningitidis from the bloodstream (CDC, 2022).