Yellow fever virus (YFV), a deadly human pathogen, is the prototype of the genus Flavivirus. Recently, YFV re-emerged in Africa and Brazil, leading to hundreds of deaths, with some cases imported to China. Prophylactic or therapeutic countermeasures are urgently needed ...
Yellow fever virus (YFV), a deadly human pathogen, is the prototype of the genus Flavivirus. Recently, YFV re-emerged in Africa and Brazil, leading to hundreds of deaths, with some cases imported to China. Prophylactic or therapeutic countermeasures are urgently needed. Previously, several human monoclonal antibodies against YFV were screened out by phage display. Here, we find that one of them, 5A, exhibits high neutralizing potency and good protection. Crystallographic analysis of the YFV envelope (E) protein in its pre- and post-fusion states shows conformations similar to those observed in other E proteins of flaviviruses. Furthermore, the structures of 5A in complex with the E protein in both states are resolved, revealing an invariant recognition site. Structural analysis and functional data suggest that 5A has high neutralization potency because it interferes with virus entry by preventing both virus attachment and fusion. These findings will be instrumental for immunogen or inhibitor design.
Organizational Affiliation: 
Laboratory of Protein Engineering and Vaccines, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin 300308, China; CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China; Research Network of Immunity and Health (RNIH), Beijing Institutes of Life Science, Chinese Academy of Sciences, Beijing 100101, China; National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing 102206, China. Electronic address: gaof@im.ac.cn.