Neisseria meningitidis serogroup A and C capsular polysaccharides (MenA/C CPS)

Neisseria meningitidis serogroup A and C capsular polysaccharides are essential carbohydrate polymers that encapsulate the meningococcus bacterium, serving as a primary virulence factor [1][2]. These polysaccharides protect the pathogen from the host's innate immune system by inhibiting phagocytosis and preventing complement-mediated lysis [3]. The serogroup A polysaccharide consists of repeating units of (1→6)-linked N-acetyl-D-mannosamine-1-phosphate, while the serogroup C polysaccharide is a homopolymer of (2→9)-linked N-acetylneuraminic acid [3]. In clinical medicine, these polysaccharides are utilized as the antigenic components of vaccines to stimulate the production of protective antibodies [4]. Conjugate vaccines, which link these polysaccharides to carrier proteins like diphtheria or tetanus toxoid, are particularly effective at inducing long-term immunological memory and reducing nasopharyngeal carriage of the bacteria [4][5]. By targeting these specific surface structures, the immune system can effectively identify and neutralize the bacteria before they cause invasive disease such as meningitis or septicemia [1]. These polysaccharides are critical for the classification of Neisseria meningitidis into distinct serogroups, which informs epidemiological tracking and global vaccine development strategies [2]. Sources: [1] CDC. Meningococcal Disease. https://www.cdc.gov/meningococcal/index.html [2] WHO. Meningococcal meningitis. https://www.who.int/news-room/fact-sheets/detail/meningococcal-meningitis [3] Harrison, O. B., et al. (2013). Description of the capsular loci of Neisseria meningitidis. Journal of Clinical Microbiology. [4] Pollard, A. J., et al. (2009). Maintaining protection against invasive bacteria with protein–polysaccharide conjugate vaccines. Nature Reviews Immunology. [5] FDA. Menactra (Meningococcal (Groups A, C, Y and W-135) Polysaccharide Diphtheria Toxoid Conjugate Vaccine) Package Insert.

Other names

Meningococcal group A and C polysaccharidesMenA and MenC capsular antigensGroup A and C meningococcal polysaccharidesNeisseria meningitidis capsular polysaccharideMeningococcal A and C polysaccharides

Vaccines containing these polysaccharides act as antigens to stimulate the production of serogroup-specific bactericidal antibodies (IgG and IgM), which facilitate complement-mediated lysis and opsonophagocytosis of the Neisseria meningitidis bacteria [1][4].