Structure-Guided Creation of an Anti-HA Stalk Antibody F11 Derivative That Neutralizes Both F11-Sensitive and -Resistant Influenza A(H1N1)pdm09 Viruses.

Osamu Kotani,Takuya Hemmi,Kaori Sano,Koshiro Tabata,Akira Ueno,Masaru Yokoyama,Yasushi Suzuki,Akira Ainai,Tadaki Suzuki,Hironori Sato,Shinji Saito,Hideki Hasegawa

doi:10.3390/v13091733

Osamu Kotani, Takuya Hemmi + Show 10 more

Open Access

https://doi.org/10.3390/v13091733

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Abstract

The stalk domain of influenza virus envelope glycoprotein hemagglutinin (HA) constitutes the axis connecting the head and transmembrane domains, and plays pivotal roles in conformational rearrangements of HA for virus infection. Here we characterized molecular interactions between the anti-HA stalk neutralization antibody F11 and influenza A(H1N1)pdm09 HA to understand the structural basis of the actions and modifications of this antibody. In silico structural analyses using a model of the trimeric HA ectodomain indicated that the F11 Fab fragment has physicochemical properties, allowing it to crosslink two HA monomers by binding to a region near the proteolytic cleavage site of the stalk domain. Interestingly, the F11 binding allosterically caused a marked suppression of the structural dynamics of the HA cleavage loop and flanking regions. Structure-guided mutagenesis of the F11 antibody revealed a critical residue in the F11 light chain for the F11-mediated neutralization. Finally, the mutagenesis led to identification of a unique F11 derivative that can neutralize both F11-sensitive and F11-resistant A(H1N1)pdm09 viruses. These results raise the possibility that F11 sterically and physically disturbs proteolytic cleavage of HA for the ordered conformational rearrangements and suggest that in silico guiding experiments can be useful to create anti-HA stalk antibodies with new phenotypes.

Highlights

Infection with the influenza virus often causes serious respiratory diseases in humans, and presents a persistent public health threat
To conduct an in silico structural study of the interactions between the F11 antibody and HA, we constructed a molecular model of the glycosylated HA trimer ectodomain docked to the F11 Fab fragment using homology modeling, molecular dynamics (MD)
The structural changes after the start of MD simulation were monitored with root mean square deviation (RMSD) [23] between the initial model structure and the structures at given time points of the MD simulation as described for HA

Summary

Introduction

Infection with the influenza virus often causes serious respiratory diseases in humans, and presents a persistent public health threat. The major immunodominant region for raising neutralization antibodies is located in a highly variable head domain of envelope glycoprotein hemagglutinin (HA) [1,2,3,4]. Antibodies that target more conserved regions have been sought to combat infection by influenza viruses [6,7,8]. Monoclonal antibodies that target the stalk domain of the HA protein have been shown to protect mice against a broad range of influenza viruses [9]. The stalk domain is located in an extracellular portion of the HA protein, and is a key structural unit for the pH-dependent conformational changes of the HA protein to gain membrane fusion activity for genome uncoating in the endosome, thereby playing essential roles in establishing virus infection in the cells [11]

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