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Antibodies to meningococcal class 1 outer-membrane protein and its variable regions in patients with systemic
I Idänpään-Heikkilä1, E A Høiby, P Chattopadhyay
1Department of Bacterial Vaccine Research and Molecular Bacteriology, National Public Health Institute, Helsinki, Finland.
Abstract:
Antibodies to the meningococcal serosubtype-specific P1.7,16 protein and its variable regions (VR) were analysed in 28 convalescent sera drawn 8-36 months after systemic meningococcal disease by immunoblotting and enzyme immunoassay (EIA) methods. EIA antigens were the meningococcal P1.7,16 protein, produced in Bacillus subtilis, and peptides covering its VR1 (P1.7 region) and VR2 (P1.16 region) inserted into a bacterial penicillinase protein. In the immunoblotting method, three meningococcal reference strains were used; they expressed either the P1.7,16 protein, or only its VR1 or VR2 epitopes in their class 1 proteins. Both methods showed a strong IgG response in four sera to P1.7,16 and VR2, but not to VR1; 18 sera had no or weak anti-class 1 protein activity. The six remaining sera were positive only on blots. The VR2-specific sera had 30-fold higher bactericidal activity than those with negligible P1.7,16 responses. Previous vaccination of the patients with a B:15:P1.7,16 meningococcal vaccine was associated with a strong anti-P1.7,16 and anti-VR2 booster response that declined with time. The subtype-specific antibody activity in some sera indicated colonisation after disease by meningococci with class 1 proteins different from the strain that had caused disease.
Insights
This study analyzed antibodies to meningococcal P1.7,16 protein and its variable regions after disease. A strong IgG response to VR2, not VR1, was observed, indicating potential colonization by different meningococcal strains.
Area of Science:
- Immunology
- Microbiology
- Vaccinology
Background:
- Neisseria meningitidis serogroup B causes significant disease.
- Meningococcal P1.7,16 protein is a key target for immune responses.
- Understanding antibody responses is crucial for vaccine development and disease control.
Purpose of the Study:
- To analyze antibodies against meningococcal P1.7,16 protein and its variable regions (VR) post-infection.
- To compare antibody responses using immunoblotting and enzyme immunoassay (EIA).
- To assess the impact of vaccination on antibody levels and bactericidal activity.
Main Methods:
- Analysis of 28 convalescent sera using immunoblotting and EIA.
- EIA utilized P1.7,16 protein and VR1/VR2 peptides.
- Immunoblotting employed meningococcal strains expressing specific P1.7,16 protein variants.
Main Results:
- A strong IgG response to P1.7,16 and VR2, but not VR1, was detected in some sera.
- VR2-specific sera exhibited significantly higher bactericidal activity.
- Previous vaccination showed a strong, but time-declining, booster response to P1.7,16 and VR2.
Conclusions:
- Antibody responses to meningococcal P1.7,16 protein are primarily directed against VR2.
- High VR2 antibody levels correlate with enhanced bactericidal activity.
- Post-disease antibody profiles may indicate colonization by distinct meningococcal subtypes.