Epitope characterization of the protective monoclonal antibody VN04-2 shows broadly neutralizing activity against highly pathogenic H5N1

The monoclonal antibody VN04-2 was previously shown to protect mice against lethal A/Vietnam/1203/04 H5N1 virus challenge when administered pre- and post-infection. In this study, we characterized the binding requirements of this antibody using direct binding to hemagglutinin and neutralization assays with H5N1 virus-like particles (H5N1-VLP) of eight recent H5N1 strains representing the major mutations within the 140s antigenic loop. Binding was clade independent and 3 mutations within this antigenic region are required before escape is possible, suggesting that apart from the H5N1 viruses circulating in Indonesia, VN04-2 may provide protection against H5N1 viruses from all other regions

Neutralizing human monoclonal antibody against H5N1 influenza HA selected from a Fab-phage display library

Identification of neutralizing antibodies with specificity away from the traditional mutation prone antigenic regions, against the conserved regions of hemagglutinin from H5N1 influenza virus has the potential to provide a therapeutic option which can be developed ahead of time in preparation for a possible pandemic due to H5N1 viruses. In this study, we used a combination of panning strategies against the hemagglutinin (HA) of several antigenic distinct H5N1 isolates to bias selection of Fab-phage from a naïve human library away from the antigenic regions of HA, toward the more conserved portions of the protein. All of the identified Fab clones which showed binding to multiple antigenically distinct HA were converted to fully human IgG, and tested for their ability to neutralize the uptake of H5N1-virus like particles (VLP) into MDCK cells. Five of the antibodies which showed binding to the relatively conserved HA2 subunit of HA, exhibited neutralization of H5N1-VLP uptake in a dose dependant manner. The inhibitory effects of these five antibodies were similar to those observed with a previously described neutralizing antibody specific for the 140s antigenic loop present within HA1 and highlight the exciting possibility that these antibodies may be efficacious against multiple H5N1 strains

Structural Mimicry of the Dengue Virus Envelope Glycoprotein Revealed by the Crystallographic Study of an Idiotype-Anti-idiotype Fab Complex

10.1128/JVI.00406-17JOURNAL OF VIROLOGY911

Epitope-directed monoclonal antibody production using a mixed antigen cocktail facilitates antibody characterization and validation

10.1038/s42003-021-01965-xCOMMUNICATIONS BIOLOGY4

Epitope-directed monoclonal antibody production using a mixed antigen cocktail facilitates antibody characterization and validation (vol 6, 441, 2021)

10.1038/s42003-021-02091-4COMMUNICATIONS BIOLOGY4