The C10 variable region is shown as ribbons with the heavy and light chains colored magenta and cyan, respectively. documents and cryo-EM maps are deposited in the Protein Data lender and Electron Microscopy Data Lender with PDB: 7A3N, 7A3O, 7A3P, 7A3Q, 7A3R, 7A3S, 7A3T, 7A3U, Deoxycholic acid sodium salt 7CTH, and EMDB: 30465. Any additional information required to reanalyze the data reported with this work paper is available from your lead contact upon request. Summary The human being monoclonal antibody C10 exhibits remarkable cross-reactivity, potently neutralizing Zika computer virus (ZIKV) and the four serotypes of dengue computer virus (DENV1CDENV4). Here we describe a comparative structure-function analysis of C10 bound to the envelope (E) protein dimers of the five viruses it neutralizes. We demonstrate the C10 Fab offers high affinity for ZIKV and DENV1 but not for DENV2, DENV3, and DENV4. We further show the C10 interaction with the second option viruses requires an E protein conformational scenery that limits binding to only Deoxycholic acid sodium salt one of the three self-employed epitopes per virion. This limited affinity is definitely however counterbalanced from the particles icosahedral business, which allows two different dimers to be reached by both Fab arms of a C10 immunoglobulin. The epitopes geometric distribution therefore confers C10 its outstanding neutralization breadth. Our results spotlight the importance not only of paratope/epitope complementarity but also the topological distribution for epitope-focused vaccine design. Keywords: Flaviviruses, Zika computer Deoxycholic acid sodium salt virus, Dengue computer virus, broadly neutralizing antibodies, vaccine design, cryo-EM, X-ray crystallography Graphical abstract Open in a separate window Shows ? The C10 Fabs orientation on E dimers allows bivalent IgG binding to each virion raft ? C10 binding to DENV2 induces E dimer rearrangement Rabbit polyclonal to beta defensin131 by hitting a spring-loaded section ? Only E dimers with asymmetric environment on DENV2 virions can bind C10 ? Bivalent binding to two different E dimers expands C10 neutralization breadth Comparative structure-function analyses reveal how the topological distribution of epitopes clarifies the cross-reactivity and neutralization of Zika and dengue viruses from the human being monoclonal antibody C10. Intro Flaviviruses are the most important arthropod-borne viral pathogens for humans, causing severe disease around the world (Collins and Metz, 2017). Among them is the highly teratogenic and Deoxycholic acid sodium salt neurotropic Zika computer virus (ZIKV), which re-emerged recently (Pierson and Diamond, 2018), and the worldwide distributed dengue viruses of serotype 1-4 (DENV1CDENV4), which impose a very high toll on general public health, with 50C100 million instances yearly. The four DENVs cause 500,000 hospitalizations yearly (Bhatt et?al., 2013) of individuals having a hemorrhagic syndrome resulting from vascular leakage (Halstead, 2007). The neutralizing antibodies induced during a DENV or ZIKV illness target the envelope (E) protein (Fibriansah and Lok, 2016) and, having a few exceptions, are serotype specific. Cross-reactive antibodies will also be elicited, which, in general, are poorly neutralizing and have been linked to antibody-dependent enhancement (ADE) of the disease upon ulterior heterotypic illness (Halstead, 2014). As a result, no efficient anti-dengue vaccine is currently available (Halstead et?al., 2020), and a potential effect of ZIKV vaccination of potentiating a subsequent dengue illness is a concern (Priyamvada et?al., 2017). An ideal vaccine should consequently protect simultaneously against all four DENVs as well as ZIKV. Only the users of a special class of human being broadly neutralizing antibodies focusing on the so-called E dimer epitope (EDE) have been shown to potently neutralize ZIKV and the four DENV serotypes (Barba-Spaeth et?al., 2016; Dejnirattisai et?al., 2015; Rouvinski et?al., 2015). C10, whose protecting effect has been shown (Swanstrom et?al., 2016), and C8 are among the broadest neutralizing monoclonal antibodies (mAbs) focusing on the EDE. Their footprints within the DENV2 and ZIKV E dimer have been structurally defined (Barba-Spaeth et?al., 2016; Rouvinski et?al., 2015; Zhang et?al., 2016; Number?1A). The epitopes are.