Epitope mapping of a bactericidal monoclonal antibody against the factor H binding protein of Neisseria meningitidis
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Peptide Scanning-assisted Identification of a Monoclonal Antibody-recognized Linear B-cell Epitope
Published on: March 24, 2017
Maria Scarselli1, Francesca Cantini, Laura Santini
1Novartis Vaccines and Diagnostics, Via Fiorentina 1, 53100 Siena, Italy.
Abstract:
The factor H binding protein (fHbp) is a 27-kDa membrane-anchored lipoprotein of Neisseria meningitidis that allows the survival of the bacterium in human plasma; it is also a major component of a universal vaccine against meningococcus B. In this study, we used nuclear magnetic resonance spectroscopy, mutagenesis, and in silico modeling to map the epitope recognized by MAb502, a bactericidal monoclonal antibody elicited by fHbp. The data show that the antibody recognizes a conformational epitope within a well-defined area of the immunodominant C-terminal domain of the protein that is formed by two loops connecting different beta-strands of a beta-barrel and a short alpha-helix brought in spatial proximity by the protein folding. The identification of the protective epitopes of fHbp is an important factor for understanding the mechanism(s) of an effective immune response and provides valuable guidelines for designing variants of the protein able to induce broadly protective immunity.
Insights
Researchers mapped the protective epitope of the factor H binding protein (fHbp) from Neisseria meningitidis. This finding aids in understanding immune responses and developing effective vaccines against meningococcus B.
Area of Science:
- Bacteriology
- Immunology
- Structural Biology
Background:
- Factor H binding protein (fHbp) is crucial for Neisseria meningitidis survival in human plasma.
- fHbp is a key target for a universal vaccine against meningococcus B.
Purpose of the Study:
- To map the epitope recognized by a bactericidal monoclonal antibody (MAb502) against fHbp.
- To understand the structural basis of antibody recognition for vaccine development.
Main Methods:
- Nuclear magnetic resonance (NMR) spectroscopy.
- Site-directed mutagenesis.
- In silico structural modeling.
Main Results:
- Identified a conformational epitope on fHbp recognized by MAb502.
- The epitope is located in the C-terminal domain, involving beta-strands and an alpha-helix.
- The antibody binds a specific region formed by protein folding.
Conclusions:
- The study elucidates the structural details of a protective epitope on fHbp.
- Understanding these epitopes is vital for designing improved meningococcal vaccines.
- This knowledge guides the development of fHbp variants for broader protective immunity.
