Toward an Improved Meningococcal Serogroup B Assay

Area of Science:

• Microbiology
• Immunology
• Vaccinology

Background:

• Invasive Neisseria meningitidis serogroup B (MenB) strains exhibit diverse surface structures, complicating vaccine efficacy prediction.
• Traditional human serum bactericidal assays (hSBA) are impractical for assessing MenB vaccine effectiveness against varied strains.
• The meningococcal antigen surface expression (MEASURE) assay quantifies factor H binding protein (fHbp) expression using flow cytometry.

Purpose of the Study:

• To evaluate the utility of the MEASURE assay in predicting MenB strain susceptibility to antibody-mediated killing.
• To map a cross-reactive antibody binding epitope relevant to MenB vaccine efficacy.
• To explore alternative, potentially more reproducible assays for MenB vaccine assessment.

Main Methods:

• Utilized flow cytometry for the meningococcal antigen surface expression (MEASURE) assay.
• Quantitated factor H binding protein (fHbp) expression on invasive MenB strains.
• Investigated antibody binding epitope mapping and strain susceptibility to killing.

Main Results:

• The MEASURE assay was explored for its potential in predicting MenB strain susceptibility to antibody-mediated killing.
• McNeil et al. mapped a cross-reactive antibody binding epitope.
• Questions remain regarding MenB strains with high fHbp expression that are nonsusceptible to anti-fHbp antibody killing.

Conclusions:

• The MEASURE assay shows potential but requires further validation for predicting MenB vaccine efficacy.
• Alternative methods like a standardized enzyme-linked immunosorbent assay (ELISA) may offer greater reproducibility and accessibility.
• Understanding strain-specific factors influencing susceptibility to antibody-mediated killing is crucial for MenB vaccine development.