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Comparison of meningococcal outer membrane protein vaccines solubilized with detergent or C polysaccharide
J T Poolman1, H A Timmermans, C T Hopman
1National Institute of Public Health and Environmental Protection, Bilthoven, The Netherlands.
Abstract:
Outer membrane proteins (OMPs) were isolated from meningococcal strain H44/76 (B:15:P1.16) by detergent extraction of bacteria. A final product containing class 1 (P1.16), 3(15), 4 OMPs and 5% (w/w) lipooligosaccharide was obtained. Two experimental vaccines were prepared: OMP-detergent and OMP-C polysaccharide. The OMP-detergent vaccine tended to show a better bactericidal: ELISA ratio for the antibodies induced as compared to the OMP-C polysaccharide vaccine. The vaccine induced bactericidal antibodies appeared for the greater part to be directed against the class 1 OMP (P1.16). By comparison of cultures grown in Mueller Hinton Broth with and without 0.25% (w/v) glucose, it was found that monoclonal antibodies against the serotype OMP (class 2 or 3) were not bactericidal against meningococci grown in MHB without glucose. Antibodies against class 1 OMP and lipooligosaccharide were not influenced by this. A new major outer membrane protein (appr. 40 kd) is described that may function as a cation-specific porin.
Insights
This study isolated outer membrane proteins (OMPs) from meningococcal strain H44/76. The OMP-detergent vaccine showed a better immune response than the OMP-C polysaccharide vaccine, with antibodies targeting class 1 OMP.
Area of Science:
- Microbiology
- Immunology
- Vaccine Development
Background:
- Neisseria meningitidis outer membrane proteins (OMPs) are crucial vaccine targets.
- Understanding OMP immunogenicity is key for developing effective meningococcal vaccines.
Purpose of the Study:
- To isolate and characterize OMPs from meningococcal strain H44/76.
- To compare the immunogenicity of two experimental meningococcal vaccines: OMP-detergent and OMP-C polysaccharide.
- To investigate the role of specific OMPs in bactericidal antibody responses.
Main Methods:
- Isolation of OMPs from *Neisseria meningitidis* strain H44/76 using detergent extraction.
- Preparation of two experimental vaccines: OMP-detergent and OMP-C polysaccharide.
- Assessment of antibody responses using bactericidal assays and ELISA.
- Cultivation of bacteria in Mueller Hinton Broth with and without glucose to evaluate antibody efficacy.
Main Results:
- The OMP-detergent vaccine induced a better bactericidal: ELISA ratio compared to the OMP-C polysaccharide vaccine.
- Bactericidal antibodies were primarily directed against class 1 OMP (P1.16).
- Monoclonal antibodies against class 2 or 3 OMPs were not bactericidal against glucose-deprived meningococci, unlike antibodies against class 1 OMP and lipooligosaccharide.
- A novel 40 kDa OMP with potential cation-specific porin function was identified.
Conclusions:
- The OMP-detergent vaccine formulation appears more promising for inducing bactericidal antibodies against *N. meningitidis*.
- Class 1 OMP (P1.16) is a significant target for bactericidal antibodies in meningococcal vaccines.
- The growth conditions of meningococci can affect the bactericidal activity of antibodies targeting specific OMPs.