Neisseria meningitidis capsular polysaccharide and surface protein

Neisseria meningitidis capsular polysaccharides are high-molecular-weight carbohydrate polymers forming a capsule around the bacterium, serving as major virulence determinants by protecting against host immune responses (especially complement-mediated killing). These polysaccharides determine the serogroup of the organism and are central to vaccine development and diagnostic approaches. Surface proteins of N. meningitidis—including pili, outer membrane adhesins (such as Opa, Opc), and conserved proteins like NspA—mediate adhesion to host tissues, invasion, and immune evasion. Both the capsule and surface proteins are vaccine targets, either individually (as in protein-based vaccines) or together (as in conjugate vaccines), and changes in their structure or expression can affect pathogenesis, diagnostics, and vaccine efficacy. The “target” in this context refers to a diverse molecular group rather than a single molecule, making it a broad but critical focal point for anti-meningococcal therapeutics and immunoprophylaxis.

Other names

Neisseria meningitidis capsulemeningococcal surface antigensNeisseria meningitidis outer membrane proteinsNm capsule

Vaccines targeting capsular polysaccharides elicit protective antibodies through opsonophagocytosis and complement-mediated lysis. Protein-based vaccines stimulate antibody-dependent immune responses against surface-exposed protein antigens (e.g., NspA elicits bactericidal antibodies).