Abstract
Hepatitis A virus (HAV), an enigmatic and ancient pathogen, is a major causative agent of acute viral hepatitis worldwide. Although there are effective vaccines, antivirals against HAV infection are still required, especially during fulminant hepatitis outbreaks. A more in-depth understanding of the antigenic characteristics of HAV and the mechanisms of neutralization could aid in the development of rationally designed antiviral drugs targeting HAV. In this paper, 4 new antibodies-F4, F6, F7, and F9-are reported that potently neutralize HAV at 50% neutralizing concentration values (neut50) ranging from 0.1 nM to 0.85 nM. High-resolution cryo-electron microscopy (cryo-EM) structures of HAV bound to F4, F6, F7, and F9, together with results of our previous studies on R10 fragment of antigen binding (Fab)-HAV complex, shed light on the locations and nature of the epitopes recognized by the 5 neutralizing monoclonal antibodies (NAbs). All the epitopes locate within the same patch and are highly conserved. The key structure-activity correlates based on the antigenic sites have been established. Based on the structural data of the single conserved antigenic site and key structure-activity correlates, one promising drug candidate named golvatinib was identified by in silico docking studies. Cell-based antiviral assays confirmed that golvatinib is capable of blocking HAV infection effectively with a 50% inhibitory concentration (IC50) of approximately 1 μM. These results suggest that the single conserved antigenic site from complete HAV capsid is a good antiviral target and that golvatinib could function as a lead compound for anti-HAV drug development.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Aminopyridines / metabolism
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Aminopyridines / pharmacology
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Antibodies, Monoclonal
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Antibodies, Neutralizing / metabolism
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Antibodies, Neutralizing / ultrastructure*
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Antibodies, Viral
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Antigens, Viral
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Capsid / metabolism
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Computer Simulation
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Drug Design*
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Epitopes
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Hepatitis A Antigens / metabolism
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Hepatitis A Antigens / ultrastructure
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Hepatitis A virus / immunology*
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Hepatitis A virus / pathogenicity
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Hepatitis A virus / ultrastructure
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Humans
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Piperazines / metabolism
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Piperazines / pharmacology
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Protein Binding
Substances
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Aminopyridines
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Antibodies, Monoclonal
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Antibodies, Neutralizing
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Antibodies, Viral
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Antigens, Viral
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Epitopes
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Hepatitis A Antigens
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N-(2-fluoro-4-((2-(4-(4-methylpiperazin-1-yl)piperidin-1-yl)carbonylaminopyridin-4-yl)oxy)phenyl)-N'-(4-fluorophenyl)cyclopropane-1,1-dicarboxamide
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Piperazines
Grants and funding
Work was supported by the Strategic Priority Research Program (XDB29010000), the Key Programs of the Chinese Academy (KJZD-SW-L05), the National Key Research and Development Program (2017YFC0840300,2017YFA0505903), National Natural Science Foundation of China (31800145, 31570717, 31770186, 31370735 and 31670737), Sichuan Province Foundation (2014KJT021-2014SZ, 2015JQO029) from the Science and Technology Department of Sichuan Province and Foundation (2016-XT00-00033-GX-01) from Chengdu HI-TECH Industrial Development Zone. X.W. was supported by Young Elite scientist sponsorship by CAST and the program C of “One Hundred of Talented People” of the Chinese Academy of Sciences.The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript