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Peptide Scanning-assisted Identification of a Monoclonal Antibody-recognized Linear B-cell Epitope
Published on: March 24, 2017
Newly isolated mAbs broaden the neutralizing epitope in murine norovirus
Abimbola O Kolawole1, Chunsheng Xia2, Ming Li2
1Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI, USA.
Abstract:
Here, we report the isolation and functional characterization of mAbs against two murine norovirus (MNV) strains, MNV-1 and WU20, which were isolated following oral infection of mice. The mAbs were screened for reactivity against the respective homologous and heterologous MNV strain by ELISA. Selected mAbs were of IgA, IgG1, IgG2a or IgG2b isotype and showed a range of Western blot reactivities from non-binding to strong binding, suggesting recognition of conformational and linear epitopes. Some of the anti-MNV-1 antibodies neutralized both MNV-1 and WU20 infections in culture and in mice, but none of the anti-WU20 mAbs neutralized either virus. The non-neutralizing anti-MNV-1 IgG2b antibody 5C4.10 was mapped to the S domain of the MNV-1 capsid, whilst the epitopes of the neutralizing anti-MNV-1 IgA antibodies 2D3.7 and 4F9.4 were mapped to the P domain. Generation of neutralization escape viruses showed that two mutations (V339I and D348E) in the C'D' loop of the MNV-1 P domain mediated escape from mAb 2D3.7 and 4F9.4 neutralization. These findings broaden the known neutralizing epitopes of MNV to the main surface-exposed loops of the P domain. In addition, the current panel of antibodies provides valuable reagents for studying norovirus biology and development of diagnostic tools.
Insights
Researchers developed monoclonal antibodies (mAbs) against murine norovirus (MNV). Some anti-MNV-1 antibodies neutralized both MNV strains, identifying key epitopes on the MNV capsid for potential diagnostic and therapeutic development.
Area of Science:
- Virology
- Immunology
- Structural Biology
Background:
- Murine norovirus (MNV) is a significant model pathogen for studying norovirus infections.
- Understanding the epitopes targeted by neutralizing antibodies is crucial for developing effective countermeasures.
Purpose of the Study:
- To isolate and functionally characterize monoclonal antibodies (mAbs) against MNV strains MNV-1 and WU20.
- To identify neutralizing epitopes on the MNV capsid and investigate mechanisms of antibody escape.
Main Methods:
- Isolation and screening of mAbs against MNV strains using ELISA and Western blot.
- Neutralization assays in cell culture and in vivo mouse models.
- Epitope mapping of mAbs to MNV capsid domains (S and P domains).
- Generation and analysis of neutralization escape mutants.
Main Results:
- Isolation of IgA and IgG mAbs with varying reactivity and neutralizing capabilities.
- Identification of neutralizing epitopes within the P domain of the MNV capsid, specifically the C'D' loop.
- Demonstration that specific mutations in the P domain confer resistance to antibody neutralization.
- Non-neutralizing mAbs targeted the S domain, while neutralizing mAbs targeted the P domain.
Conclusions:
- The study identifies novel neutralizing epitopes on the MNV P domain, expanding the understanding of norovirus immunopathogenesis.
- The generated mAbs serve as valuable tools for norovirus research, diagnostics, and potential therapeutic strategies.
- Antibody escape mechanisms highlight the dynamic interaction between MNV and the host immune system.
