Neisseria meningitidis serogroup A polysaccharide antigen-conjugate complex (MenA conjugate)

The Neisseria meningitidis serogroup A polysaccharide antigen-conjugate complex is the active component in several vaccines designed to prevent invasive disease caused by Neisseria meningitidis serogroup A. This target consists of a purified capsular polysaccharide from N. meningitidis serogroup A, which is chemically conjugated to a carrier protein (commonly diphtheria toxoid or tetanus toxoid) to enhance immunogenicity, especially in young children. The capsular polysaccharide is the main virulence determinant of N. meningitidis serogroup A, consisting of repeating units of (α1→6)-linked N-acetylmannosamine-1-phosphate that are partially O-acetylated. The conjugation to a carrier protein transforms the T-cell independent response elicited by plain polysaccharides into a T-cell dependent response, resulting in stronger and longer-lasting immunity. Upon administration, the immune system recognizes both the carbohydrate epitope and the carrier protein, leading to robust production of high-affinity antibodies against MenA capsule and development of immune memory. Vaccines based on this target have been highly effective in preventing epidemics caused by MenA strains, most notably through mass vaccination campaigns in Africa’s “meningitis belt” using products like MenAfriVac (PsA-TT).

Other names

MenA polysaccharide-conjugateN. meningitidis serogroup A capsular polysaccharide conjugatePsA-TTMenAfriVac antigen

Induces T-dependent antibody response against Neisseria meningitidis serogroup A capsular polysaccharide.