While the outbreak of ZIKV in the Americas is likely to subside in the next 1-2 years, there is going to be an ongoing risk of congenital Zika syndrome in babies born to mothers exposed to ZIKV during pregnancy. There is no licensed vaccine or treatment to combat ZIKV infection. Because of the urgent need for a ZIKV vaccine, and a finite time in which efficacy could be demonstrated in the current outbreak, we focused on developing a DNA vaccine, which can be rapidly produced and can easily modified using reverse genetics techniques. The first generation DNA vaccines are based on prior success in West Nile Virus. We designed and evaluated two lead DNA vaccine candidates which produce subviral particles (SVP) after transfection. The first candidate (VRC5283) expresses the prM and E proteins from the ZIKV French Polynesia 2014 strain. The other (VRC5288) is a ZIKV/JEV chimera virus and was designed with the final 98 amino acids of (comprising the transmembrane and stem domains from JEV) swapped for the corresponding regions from ZIKV which has been demonstrated to improve SVP secretion for other flaviviruses. Immunization with these constructs generated robust neutralizing antibody responses in mice and rhesus macaques. Two doses of DNA vaccine candidates expressing the prM and E proteins of Zika virus protected 17 out of 18 rhesus macaques from viremia after Zika virus challenge. This protection was correlated with serum neutralizing activity. A single dose of DNA vaccine did not completely prevent infection, but significantly reduced the level of viremia in Zika virus challenged rhesus macaques. Subsequently, we have continued to study the two DNA vaccines by performing dose de-escalation studies to determine the neutralizing antibody threshold of protection, and correlates of protection. Additionally, we have collaborated with multiple groups to help develop alternative ZIKV vaccines, including mRNA-based and live-attenuated vaccines. Nipah Virus (NiV) circulates in animal reservoirs and has caused sporadic outbreaks in humans in India and South East Asia. NiV is transmitted by the respiratory route, but can develop into a highly fatal neurologic disease. There is no licensed vaccine or treatment for NiV, although a G protein vaccine, and mAb from the related Hendra virus are currently being developed for Nipah. We have begun to use structure-based design to stabilize the fusion protein in its prefusion confirmation to use as a vaccine immunogen. Based on the establishment of G antibodies as a correlate of protection for Hendra virus, we also developed oligomeric G protein vaccines and chimeric vaccine that expresses the Pre-F and G protein. These vaccines are highly immunogenic in the protein and mRNA platforms and mRNA vaccines expressing these antigens will be evaluated in the ferret challenge model. Enterovirus D68 causes biannual respiratory illnesses in pediatric populations, and has been temporally related to outbreaks of acute flacid myelitis (AFM). We have begun efforts to develop a VLP vaccine that expresses the structural proteins of EV-D68.
We aim to apply the knowledge from this project to develop an enterovirus vaccine platform that can be used for vaccines against related enteroviruses.
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| Goo, Leslie; DeMaso, Christina R; Pelc, Rebecca S et al. (2018) The Zika virus envelope protein glycan loop regulates virion antigenicity. Virology 515:191-202 |
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| Shan, Chao; Muruato, Antonio E; Jagger, Brett W et al. (2017) A single-dose live-attenuated vaccine prevents Zika virus pregnancy transmission and testis damage. Nat Commun 8:676 |
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| Dowd, Kimberly A; DeMaso, Christina R; Pelc, Rebecca S et al. (2016) Broadly Neutralizing Activity of Zika Virus-Immune Sera Identifies a Single Viral Serotype. Cell Rep 16:1485-1491 |
| Dowd, Kimberly A; Ko, Sung-Youl; Morabito, Kaitlyn M et al. (2016) Rapid development of a DNA vaccine for Zika virus. Science 354:237-240 |
| Tumurkhuu, Gantsetseg; Dagvadorj, Jargalsaikhan; Jones, Heather D et al. (2015) Alternatively spliced myeloid differentiation protein-2 inhibits TLR4-mediated lung inflammation. J Immunol 194:1686-94 |
