Human Monoclonal Antibodies Potently Neutralize Zika Virus and Select for Escape Mutations on the Lateral Ridge of the Envelope Protein

Abstract

The mosquito-borne Zika virus (ZIKV) has been causing epidemic outbreaks on a global scale. Virus infection can result in severe disease in humans, including microcephaly in newborns and Guillain-Barré syndrome in adults. Here, we characterized monoclonal antibodies isolated from a patient with an active Zika virus infection that potently neutralized virus infection in Vero cells at the nanogram-per-milliliter range. In addition, these antibodies enhanced internalization of virions into human leukemia K562 cells in vitro, indicating their possible ability to cause antibody-dependent enhancement of disease. Escape variants of the ZIKV MR766 strain to a potently neutralizing antibody, AC10, exhibited an amino acid substitution at residue S368 in the lateral ridge region of the envelope protein. Analysis of publicly availably ZIKV sequences revealed the S368 site to be conserved among the vast majority (97.6%) of circulating strains. We validated the importance of this residue by engineering a recombinant virus with an S368R point mutation that was unable to be fully neutralized by AC10. Four out of the 12 monoclonal antibodies tested were also unable to neutralize the virus with the S368R mutation, suggesting this region to be an important immunogenic epitope during human infection. Last, a time-of-addition infection assay further validated the escape variant and showed that all monoclonal antibodies inhibited virus binding to the cell surface. Thus, the present study demonstrates that the lateral ridge region of the envelope protein is likely an immunodominant, neutralizing epitope. IMPORTANCE Zika virus (ZIKV) is a global health threat causing severe disease in humans, including microcephaly in newborns and Guillain-Barré syndrome in adults. Here, we analyzed the human monoclonal antibody response to acute ZIKV infection and found that neutralizing antibodies could not elicit Fc-mediated immune effector functions but could potentiate antibody-dependent enhancement of disease. We further identified critical epitopes involved with neutralization by generating and characterizing escape variants by whole-genome sequencing. We demonstrate that the lateral ridge region, particularly the S368 amino acid site, is critical for neutralization by domain IIIspecific antibodies.Z ika virus (ZIKV) is a mosquito-borne flavivirus causing epidemic outbreaks on a global scale. Infection with ZIKV is frequently asymptomatic, and clinical manifestations, including low-grade fever, rash, and arthralgia, occur in approximately 20% of

A protective Zika virus E-dimer-based subunit vaccine engineered to abrogate antibody-dependent enhancement of dengue infection

“…The mAbs HM14c10, 5J7 and ZIKV-117 bind to epitopes defined by the arrangement of two or more E dimers on the viral surface of DENV1, DENV3 and ZIKV, respectively 28–30 , while the epitopes targeted by the mAbs 2D22 and ZIKV-195 are contained within the E-dimer interfaces of DENV2 and ZIKV 31,32 . Furthermore, antibodies to complex quaternary epitopes such as the EDE are resistant to ZIKV escape mutation 26 , whereas virus escape from E domain Ill-specific mAbs can lead to the rapid generation of viral escape mutants 33,34 .…”

Somatic Hypermutation and Framework Mutations of Variable Region Contribute to Anti-Zika Virus-Specific Monoclonal Antibody Binding and Function

“…Three of the rabbit MAbs described here map to the domain III lateral ridge, a region that is also targeted by several mouse and human MAbs that have demonstrated ZIKV-neutralizing activity and protective immunity in mouse models, suggesting that this is an immunodominant region for ZIKV-specific neutralizing antibodies in multiple species ( 45 , 47 , 48 , 51 ). The epitopes recognized by MAbs 102-1 and 270-12 include residue S368 in the domain III lateral ridge, which has been determined to be an important residue for human ZIKV-specific neutralizing antibodies ( 52 ). MAb 242-3 also recognized the domain III lateral ridge, but while S368 was not identified as a critical residue, the adjacent residues T369 and E370 were identified as critical.…”

Dengue, West Nile, and Zika Viruses: Potential Novel Antiviral Biologics Drugs Currently at Discovery and Preclinical Development Stages

“…In their studies, Bailey et al characterized several neutralizing monoclonal antibodies (mAbs) isolated from a patient with acute Zika virus infection [37]. Their purpose was to map the epitopes targeted by neutralizing antibodies and try to understand whether certain germline rearrangements provided better neutralizing responses [37]. AC-10 was one of four antibodies that demonstrated high neutralizing potency against ZIKV [37].…”