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Analysis of HBV-Specific CD4 T-cell Responses and Identification of HLA-DR-Restricted CD4 T-Cell Epitopes Based on a Peptide Matrix
Published on: October 20, 2021
Neutralization epitope responsible for the hepatitis B virus subtype-specific protection in chimpanzees
Pei Zhang1, Mei-Ying W Yu, Richard Venable
1Division of Hematology and Laboratory of Biophysics, Center for Biologics Evaluation and Research, Food and Drug Administration, Bethesda, MD 20892, USA. pei.zhang@fda.hhs.gov
A hepatitis B virus (HBV) antibody (BX-182) specifically neutralizes HBV subtype "d" by targeting a critical epitope in the pre-S1 region. This subtype-specific protection highlights a potential HBV escape mechanism.
Area of Science:
- Virology
- Immunology
- Structural Biology
Background:
- Hepatitis B virus (HBV) infection is a major global health concern.
- Neutralizing monoclonal antibodies are investigated as potential therapeutics.
- Understanding HBV subtype-specific immune responses is crucial for vaccine and drug development.
Purpose of the Study:
- To elucidate the mechanism behind the subtype-specific protection conferred by the neutralizing monoclonal antibody BX-182.
- To identify the neutralization epitope responsible for the observed protection against HBV.
Main Methods:
- Screening of random peptide phage libraries.
- Bioinformatics analysis of HBV genetic variants.
- Structure analysis of the antibody-epitope interaction.
- Chimpanzee inoculation studies with different HBV subtypes.
Main Results:
- The neutralizing antibody BX-182 targets an epitope in the pre-S1 region (residues 17-21) of the HBV surface antigen.
- The residues Val-18/Pro-19 within the epitope are critical for BX-182 binding.
- BX-182 demonstrated protection against HBV subtype adw but not ayw in chimpanzees.
- Sequence analysis revealed variations in the epitope across different HBV subtypes and genotypes, affecting antibody binding.
Conclusions:
- BX-182 exhibits subtype-specific neutralization of HBV by binding to the "d" epitope in the pre-S1 region.
- Variations in the epitope sequence and conformation among HBV subtypes explain the differential protection.
- These findings suggest a potential escape mechanism for HBV genetic variants against antibody-mediated neutralization.
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