Project Summary
Flaviviruses are enveloped, single-stranded RNA viruses that cause epidemics of debilitating human disease on
a global scale. The four serotypes of dengue virus (DENV) cause up to ~100 million infections per year including
life-threatening shock syndrome. Zika virus (ZIKV) is linked to microcephaly and congenital malformations. Tick-
borne flaviviruses (TBFV) are emergent threats that cause encephalitis, long-term neurological sequelae, and
death. No specific therapy is available for any flavivirus. Flaviviruses adopt ensembles of structures in which
certain antibody epitopes are exposed or hidden. Elucidating how antibodies recognize different structural
ensembles of flavivirus virions can enhance our understanding of their functional properties including neutralizing
activity. In this competitive renewal application, our long-standing collaborative team (Diamond, Kuhn, Fremont,
Crowe, and Pierson) proposes to continue studying structural mechanisms of antibody recognition and
neutralization of flaviviruses. We will define the functional properties of protective antibodies that neutralize
DENV and ZIKV in a conformationally-restricted manner. We will use these antibodies to probe the spectrum of
structures sampled by flaviviruses and how this influences epitope exposure. We also will perform new
campaigns to identify neutralizing antibodies against ZIKV and the distantly-related tick-borne flaviviruses that
recognize quaternary epitopes. We will use this information to engineer ZIKV subviral particles (prM-E; SVPs)
that optimally enable binding of neutralizing antibodies including those quaternary epitopes spanning dimer rafts.
Genetically modified ZIKV SVPs will be tested for improved immunogenicity and protection in mice. Overall, our
experiments will provide new insight into the dynamic states of flaviviruses and the nature of accessible
neutralizing antibody epitopes. These studies may facilitate the generation of novel sculpted antigens and
immunogens with improved capacity to detect and elicit specific protective antibody responses against DENV,
ZIKV, and likely other emerging flaviviruses.