Neisseria meningitidis group C polysaccharide conjugated to tetanus toxoid protein

The antigen is a linear homopolymer of α(2→9)-linked sialic acid (N-acetylneuraminic acid) residues, also known as polysialic acid, isolated from the capsular polysaccharide of *Neisseria meningitidis* serogroup C. It is chemically conjugated to tetanus toxoid, a carrier protein chosen for its strong immunogenicity and safety profile, via reductive amination. This conjugation transforms the poorly immunogenic polysaccharide into a T cell-dependent antigen. In conjugate vaccines, such as NeisVac-C®, this molecule triggers immune responses by presenting carrier protein-derived peptides to CD4+ T cells, inducing memory and robust protective antibody responses specific for the group C polysaccharide. This mechanism is crucial for achieving effective and long-lasting protection, preventing invasive meningococcal disease (like meningitis and septicemia) caused by *Neisseria meningitidis* serogroup C in vaccinated individuals. A limitation is that it only provides immunity against serogroup C, not other meningococcal serogroups or unrelated pathogens.

Other names

Meningococcal group C polysaccharide-tetanus toxoid conjugateMenC-TT conjugateGroup C meningococcal polysaccharide conjugateMeningococcal C conjugate vaccine antigen

Induction of a T-dependent immune response via presentation of carrier protein peptides to CD4+ helper T cells, leading to memory B cell activation and generation of anti-capsular polysaccharide antibodies