CP

Group B N. meningitidis (MenB), which is responsible for up to 80% of the total cases of disease in industrialized countries, has been resistant to any attempt to develop a capsulebased vaccine due to the poor immunogenicity of the CP even after protein conjugation. This is probably due to the similarity between the MenB CP and a polymer expressed on the neuronal cell adhesion molecule of mammalian tissues. Both polysaccharides are homolinear polymers of N-acetylneuraminic acid (polysialic acid), although the bacterial CP is longer than human polysialic acid (200 vs 50 residues, respectively). Therefore, the MenB CP is a self-Ag unable to stimulate an immune response and with the potential to induce autoimmunity if used as a vaccine.