Host: Rabbit Polyclonal
Neisseria meningitidis is a causative agent of bacterial meningitis and resides within the nasopharyngeal tract of humans. Strains of N. meningitidis are characterized by the polysaccharide expressed on its capsule. Serogroups A, B and C cause 90% of meningococcal meningitis cases. The carbohydrate component of the capsular membrane induces a T independent immune response so neither long term immunity by memory cell formation nor antibody affinity maturation is observed. Rather than being engulfed and processed by an antigen presenting cell,the carbohydrate capsule interacts directly with B cells. This interaction causes production of serogroup specific antibodies, primarily IgM. IgG is also produced with an IgG1 response predominating in children and an IgG2 response predominating in adults. The immune systems of infants are not sufficiently developed to achieve an immune response to the polysaccharide membrane which accounts for the prevalence of meningitis in this age group. Persons most susceptible to the infection are often immunocompromised, immunosuppressed or suffering from head trauma. Others acquire infection through close contact with a primary carrier.
- N meningitidis