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PorB3 outer membrane protein on Neisseria meningitidis is poorly accessible for antibody binding on live bacteria

T E Michaelsen1, A Aase, J Kolberg

  • 1Department of Vaccinology, National Institute of Public Health, P.O. Box 4404 Torshov, 0403, Oslo, Norway. terje.michaelsen@folkehelsa.no

Vaccine
|February 13, 2001
PubMed

Insights

Antibodies poorly bind Neisseria meningitidis PorB3 porin on live bacteria, unlike PorB2 and PorA. This suggests PorB3 is not an optimal target for vaccine-induced protective antibodies.

Area of Science:

  • Microbiology
  • Immunology
  • Bacterial Outer Membrane Proteins

Background:

  • Neisseria meningitidis is a leading cause of bacterial meningitis.
  • Outer membrane proteins like PorA and PorB are key targets for vaccines.
  • Accessibility of surface proteins affects immune responses.

Purpose of the Study:

  • To investigate the antibody accessibility of PorB3 porin on live Neisseria meningitidis.
  • To compare PorB3 accessibility with other outer membrane proteins (PorA, PorB2).
  • To evaluate PorB3 as a potential target for protective antibodies.

Main Methods:

  • Flow cytometry analysis of live and ethanol-killed Neisseria meningitidis.
  • Utilized mouse monoclonal antibodies (mAbs) and patient/post-vaccination sera.
  • Tested antibodies specific to PorB3, PorB2, and PorA proteins.

Main Results:

  • PorB3 porins on live bacteria showed poor antibody accessibility.
  • PorB2 and PorA outer membrane proteins exhibited high antibody accessibility.
  • Strong antibody binding to PorB3 was observed only after bacterial killing.

Conclusions:

  • Lipopolysaccharide (LPS) shielding and short extracellular loops likely limit PorB3 epitope exposure.
  • PorB3 is not an optimal target for developing protective antibodies via vaccination.
  • Understanding protein accessibility is crucial for effective vaccine design against Neisseria meningitidis.

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