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Development and characterisation of outer membrane vesicle vaccines against serogroup A Neisseria meningitidis

Gunnstein Norheim1, Audun Aase, Dominique A Caugant

  • 1Division of Infectious Disease Control, Norwegian Institute of Public Health, P.O. Box 4404 Nydalen, NO-0403 Oslo, Norway.

Vaccine
|May 17, 2005
PubMed

Insights

Outer membrane vesicle (OMV) vaccines derived from Neisseria meningitidis serogroup A show promise for preventing meningitis epidemics in Africa. These OMV vaccines induce robust immune responses, including high serum bactericidal activity, in mice.

Area of Science:

  • Microbiology
  • Immunology
  • Vaccinology

Background:

  • Neisseria meningitidis serogroup A causes recurrent meningitis epidemics in Africa.
  • Previous studies showed outer membrane vesicle (OMV) vaccines from subgroup III serogroup A meningococci induced serum bactericidal activity (SBA) in mice.

Purpose of the Study:

  • To investigate the properties of OMV vaccines from five different subgroup III serogroup A meningococcal strains.
  • To evaluate the immunogenicity and efficacy of these OMV vaccines in a mouse model.

Main Methods:

  • OMV vaccines were produced from serogroup A meningococcal strains grown in low-iron synthetic medium.
  • Mice were immunized with OMV vaccines, and immune responses were analyzed via immunoblotting, ELISA, serum bactericidal assays (SBA), and flow cytometry.
  • Antibody responses were assessed against various outer membrane proteins and lipooligosaccharides.

Main Results:

  • OMV vaccines induced antibodies with high SBA and opsonophagocytic activity against Neisseria meningitidis serogroup A.
  • The strongest IgG antibody responses were directed against the PorA outer membrane protein.
  • Significant SBA was observed against a subgroup III strain lacking PorA, but not against a clone IV-1 strain.

Conclusions:

  • OMV vaccines derived from subgroup III serogroup A meningococci are immunogenic and elicit potent bactericidal antibodies in mice.
  • These OMV vaccines represent a potential alternative to polysaccharide and conjugate polysaccharide vaccines for controlling serogroup A meningococcal meningitis in Africa.

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