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Zhang HQ, Li N, Zhang ZR, Deng CL, Xia H, Ye HQ, Yuan ZM, Zhang B. A Chimeric Classical Insect-Specific Flavivirus Provides Complete Protection Against West Nile Virus Lethal Challenge in Mice. J Infect Dis 2024; 229:43-53. [PMID: 37368353 DOI: 10.1093/infdis/jiad238] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2023] [Revised: 06/15/2023] [Accepted: 06/23/2023] [Indexed: 06/28/2023] Open
Abstract
West Nile virus (WNV), an arthropod-borne flavivirus, can cause severe symptoms, including encephalitis, and death, posing a threat to public health and the economy. However, there is still no approved treatment or vaccine available for humans. Here, we developed a novel vaccine platform based on a classical insect-specific flavivirus (cISF) YN15-283-02, which was derived from Culicoides. The cISF-WNV chimera was constructed by replacing prME structural genes of the infectious YN15-283-02 cDNA clone with those of WNV and successfully rescued in Aedes albopictus cells. cISF-WNV was nonreplicable in vertebrate cells and nonpathogenic in type I interferon receptor (IFNAR)-deficient mice. A single-dose immunization of cISF-WNV elicited considerable Th1-biased antibody responses in C57BL/6 mice, which was sufficient to offer complete protection against lethal WNV challenge with no symptoms. Our studies demonstrated the potential of the insect-specific cISF-WNV as a prophylactic vaccine candidate to prevent infection with WNV.
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Affiliation(s)
- Hong-Qing Zhang
- Key Laboratory of Special Pathogens and Biosafety, Wuhan Institute of Virology, Center for Biosafety Mega-Science, Chinese Academy of Sciences, Wuhan, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Na Li
- Key Laboratory of Special Pathogens and Biosafety, Wuhan Institute of Virology, Center for Biosafety Mega-Science, Chinese Academy of Sciences, Wuhan, China
| | - Zhe-Rui Zhang
- Key Laboratory of Special Pathogens and Biosafety, Wuhan Institute of Virology, Center for Biosafety Mega-Science, Chinese Academy of Sciences, Wuhan, China
| | - Cheng-Lin Deng
- Key Laboratory of Special Pathogens and Biosafety, Wuhan Institute of Virology, Center for Biosafety Mega-Science, Chinese Academy of Sciences, Wuhan, China
| | - Han Xia
- Key Laboratory of Special Pathogens and Biosafety, Wuhan Institute of Virology, Center for Biosafety Mega-Science, Chinese Academy of Sciences, Wuhan, China
- University of Chinese Academy of Sciences, Beijing, China
- Hubei Jiangxia Laboratory, Wuhan, China
| | - Han-Qing Ye
- Key Laboratory of Special Pathogens and Biosafety, Wuhan Institute of Virology, Center for Biosafety Mega-Science, Chinese Academy of Sciences, Wuhan, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Zhi-Ming Yuan
- Key Laboratory of Special Pathogens and Biosafety, Wuhan Institute of Virology, Center for Biosafety Mega-Science, Chinese Academy of Sciences, Wuhan, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Bo Zhang
- Key Laboratory of Special Pathogens and Biosafety, Wuhan Institute of Virology, Center for Biosafety Mega-Science, Chinese Academy of Sciences, Wuhan, China
- University of Chinese Academy of Sciences, Beijing, China
- Hubei Jiangxia Laboratory, Wuhan, China
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Unali G, Crivicich G, Pagani I, Abou‐Alezz M, Folchini F, Valeri E, Matafora V, Reisz JA, Giordano AMS, Cuccovillo I, Butta GM, Donnici L, D'Alessandro A, De Francesco R, Manganaro L, Cittaro D, Merelli I, Petrillo C, Bachi A, Vicenzi E, Kajaste‐Rudnitski A. Interferon‐inducible phospholipids govern
IFITM3
‐dependent endosomal antiviral immunity. EMBO J 2023; 42:e112234. [PMID: 36970857 PMCID: PMC10183820 DOI: 10.15252/embj.2022112234] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2022] [Revised: 02/27/2023] [Accepted: 03/06/2023] [Indexed: 03/29/2023] Open
Abstract
The interferon-induced transmembrane proteins (IFITM) are implicated in several biological processes, including antiviral defense, but their modes of action remain debated. Here, taking advantage of pseudotyped viral entry assays and replicating viruses, we uncover the requirement of host co-factors for endosomal antiviral inhibition through high-throughput proteomics and lipidomics in cellular models of IFITM restriction. Unlike plasma membrane (PM)-localized IFITM restriction that targets infectious SARS-CoV2 and other PM-fusing viral envelopes, inhibition of endosomal viral entry depends on lysines within the conserved IFITM intracellular loop. These residues recruit Phosphatidylinositol 3,4,5-trisphosphate (PIP3) that we show here to be required for endosomal IFITM activity. We identify PIP3 as an interferon-inducible phospholipid that acts as a rheostat for endosomal antiviral immunity. PIP3 levels correlated with the potency of endosomal IFITM restriction and exogenous PIP3 enhanced inhibition of endocytic viruses, including the recent SARS-CoV2 Omicron variant. Together, our results identify PIP3 as a critical regulator of endosomal IFITM restriction linking it to the Pi3K/Akt/mTORC pathway and elucidate cell-compartment-specific antiviral mechanisms with potential relevance for the development of broadly acting antiviral strategies.
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3
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Li N, Deng CL, Li Q, Chen XL, Zhang B, Ye HQ. A safe replication-defective Zika virus vaccine protects mice from viral infection and vertical transmission. Antiviral Res 2023; 211:105549. [PMID: 36690159 DOI: 10.1016/j.antiviral.2023.105549] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2022] [Revised: 01/18/2023] [Accepted: 01/19/2023] [Indexed: 01/22/2023]
Abstract
With the explosive emergence of Zika virus (ZIKV) and the consequent devastating fetal malformations in infected expectant women, a safe and effective vaccine is urgently needed. Here, using our established NS1 trans-complementation system, we generated high titer of replication-defective ZIKV with NS1 deletion (ZIKV-ΔNS1) in the BHK-21 cell line stably expressing NS1 (BHKNS1). NS1 deletion of ZIKV-ΔNS1 was stably maintained as no replicative virus was found in naïve BHK-21 cells after continuous passaging of ZIKV-ΔNS1 in BHKNS1 cells. The safety of ZIKV-ΔNS1 was demonstrated when a high dose of ZIKV-ΔNS1 (107 IU) was used to infect the highly susceptible type I and type II interferon (IFN) receptor-deficient mice. ZIKV-ΔNS1 could induce antibody responses in both immunocompetent (BALB/c) and immunodeficient mice and a single dose of ZIKV-ΔNS1 vaccine protected the immunodeficient mice from a highly lethal dosage of challenge with WT ZIKV. ZIKV-ΔNS1 immunization also attenuated vertical transmission during pregnancy of type I IFN receptor-deficient IFNAR-/- mice and protected fetuses from ZIKV infection. Our data reported here not only provide a promising ZIKV vaccine candidate with a satisfied balance between safety and efficacy, but also demonstrate the potential of the NS1 trans-complementation system as a platform for flavivirus vaccine development, especially for highly pathogenic flaviviruses.
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Affiliation(s)
- Na Li
- Key Laboratory of Special Pathogens and Biosafety, Wuhan Institute of Virology, Center for Biosafety Mega-Science, Chinese Academy of Sciences, Wuhan, 430071, China
| | - Cheng-Lin Deng
- Key Laboratory of Special Pathogens and Biosafety, Wuhan Institute of Virology, Center for Biosafety Mega-Science, Chinese Academy of Sciences, Wuhan, 430071, China
| | - Qi Li
- College of Pharmacy and Drug Discovery Center for Infectious Diseases, Nankai University, Tianjin, 300350, China
| | - Xiao-Ling Chen
- Key Laboratory of Special Pathogens and Biosafety, Wuhan Institute of Virology, Center for Biosafety Mega-Science, Chinese Academy of Sciences, Wuhan, 430071, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Bo Zhang
- Key Laboratory of Special Pathogens and Biosafety, Wuhan Institute of Virology, Center for Biosafety Mega-Science, Chinese Academy of Sciences, Wuhan, 430071, China.
| | - Han-Qing Ye
- Key Laboratory of Special Pathogens and Biosafety, Wuhan Institute of Virology, Center for Biosafety Mega-Science, Chinese Academy of Sciences, Wuhan, 430071, China.
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4
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Li N, Deng CL, Zhang B, Ye HQ. Viral Titer Quantification of West Nile Virus by Immunostaining Plaque Assay. Methods Mol Biol 2023; 2585:15-21. [PMID: 36331761 DOI: 10.1007/978-1-0716-2760-0_3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Immunostained plaque assay based on the specific antibody binding to viral antigen enables the detection and titration of virus infectivity, especially for viruses that could not form plaques using the classical crystal violet or neutral red staining methods. Here we describe the application of this method to quantify viral titers of wild-type West Nile virus (WNV-WT) and replication-defective WNV-ΔNS1 virus.
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Affiliation(s)
- Na Li
- Key Laboratory of Special Pathogens and Biosafety, Wuhan Institute of Virology, Center for Biosafety Mega-Science, Chinese Academy of Sciences, Wuhan, China
| | - Cheng-Lin Deng
- Key Laboratory of Special Pathogens and Biosafety, Wuhan Institute of Virology, Center for Biosafety Mega-Science, Chinese Academy of Sciences, Wuhan, China
| | - Bo Zhang
- Key Laboratory of Special Pathogens and Biosafety, Wuhan Institute of Virology, Center for Biosafety Mega-Science, Chinese Academy of Sciences, Wuhan, China.
| | - Han-Qing Ye
- Key Laboratory of Special Pathogens and Biosafety, Wuhan Institute of Virology, Center for Biosafety Mega-Science, Chinese Academy of Sciences, Wuhan, China
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Li N, Wang Z, Wang R, Zhang ZR, Zhang YN, Deng CL, Zhang B, Shang LQ, Ye HQ. In Vitro Inhibition of Alphaviruses by Lycorine. Virol Sin 2021; 36:1465-1474. [PMID: 34374926 PMCID: PMC8353614 DOI: 10.1007/s12250-021-00438-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2021] [Accepted: 06/08/2021] [Indexed: 11/25/2022] Open
Abstract
Chikungunya virus (CHIKV) is a mosquito-borne alphavirus. As an emerging virus, CHIKV imposes a threat to public health. Currently, there are no vaccines or antivirals available for the prevention of CHIKV infection. Lycorine, an alkaloid from Amaryllidaceae plants, has antiviral activity against a number of viruses such as coronavirus, flavivirus and enterovirus. In this study, we found that lycorine could inhibit CHIKV in cell culture at a concentration of 10 μmol/L without apparent cytotoxicity. In addition, it exhibited broad-spectrum anti-alphavirus activity, including Sindbis virus (SINV), Semliki Forest virus (SFV), and Venezuelan equine encephalomyelitis virus (VEEV). The time of addition studies indicated that lycorine functions at an early post-entry stage of CHIKV life cycle. The results based on two different CHIKV replicons provided further evidence that lycorine exerts its antiviral activity mainly by inhibiting CHIKV translation. Overall, our study extends the antiviral spectrum of lycorine.
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Affiliation(s)
- Na Li
- Key Laboratory of Special Pathogens and Biosafety, Center for Biosafety Mega-Science, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, 430071, China
| | - Zhen Wang
- Key Laboratory of Special Pathogens and Biosafety, Center for Biosafety Mega-Science, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, 430071, China
| | - Rui Wang
- College of Pharmacy and Drug Discovery Center for Infectious Diseases, Nankai University, Tianjin, 300350, China
| | - Zhe-Rui Zhang
- Key Laboratory of Special Pathogens and Biosafety, Center for Biosafety Mega-Science, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, 430071, China
| | - Ya-Nan Zhang
- Key Laboratory of Special Pathogens and Biosafety, Center for Biosafety Mega-Science, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, 430071, China
| | - Cheng-Lin Deng
- Key Laboratory of Special Pathogens and Biosafety, Center for Biosafety Mega-Science, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, 430071, China
| | - Bo Zhang
- Key Laboratory of Special Pathogens and Biosafety, Center for Biosafety Mega-Science, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, 430071, China. .,College of Pharmacy and Drug Discovery Center for Infectious Diseases, Nankai University, Tianjin, 300350, China.
| | - Lu-Qing Shang
- College of Pharmacy and Drug Discovery Center for Infectious Diseases, Nankai University, Tianjin, 300350, China.
| | - Han-Qing Ye
- Key Laboratory of Special Pathogens and Biosafety, Center for Biosafety Mega-Science, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, 430071, China.
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Carpio KL, Barrett ADT. Flavivirus NS1 and Its Potential in Vaccine Development. Vaccines (Basel) 2021; 9:622. [PMID: 34207516 PMCID: PMC8229460 DOI: 10.3390/vaccines9060622] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Revised: 06/03/2021] [Accepted: 06/04/2021] [Indexed: 12/19/2022] Open
Abstract
The Flavivirus genus contains many important human pathogens, including dengue, Japanese encephalitis (JE), tick-borne encephalitis (TBE), West Nile (WN), yellow fever (YF) and Zika (ZIK) viruses. While there are effective vaccines for a few flavivirus diseases (JE, TBE and YF), the majority do not have vaccines, including WN and ZIK. The flavivirus nonstructural 1 (NS1) protein has an unusual structure-function because it is glycosylated and forms different structures to facilitate different roles intracellularly and extracellularly, including roles in the replication complex, assisting in virus assembly, and complement antagonism. It also plays a role in protective immunity through antibody-mediated cellular cytotoxicity, and anti-NS1 antibodies elicit passive protection in animal models against a virus challenge. Historically, NS1 has been used as a diagnostic marker for the flavivirus infection due to its complement fixing properties and specificity. Its role in disease pathogenesis, and the strong humoral immune response resulting from infection, makes NS1 an excellent target for inclusion in candidate flavivirus vaccines.
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Affiliation(s)
- Kassandra L. Carpio
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, TX 77555, USA;
| | - Alan D. T. Barrett
- Department of Pathology, University of Texas Medical Branch, Galveston, TX 77555, USA
- Sealy Institute for Vaccine Sciences, University of Texas Medical Branch, Galveston, TX 77555, USA
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Trovato M, Sartorius R, D’Apice L, Manco R, De Berardinis P. Viral Emerging Diseases: Challenges in Developing Vaccination Strategies. Front Immunol 2020; 11:2130. [PMID: 33013898 PMCID: PMC7494754 DOI: 10.3389/fimmu.2020.02130] [Citation(s) in RCA: 55] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Accepted: 08/06/2020] [Indexed: 12/11/2022] Open
Abstract
In the last decades, a number of infectious viruses have emerged from wildlife or re-emerged, generating serious threats to the global health and to the economy worldwide. Ebola and Marburg hemorrhagic fevers, Lassa fever, Dengue fever, Yellow fever, West Nile fever, Zika, and Chikungunya vector-borne diseases, Swine flu, Severe acute respiratory syndrome (SARS), Middle East respiratory syndrome (MERS), and the recent Coronavirus disease 2019 (COVID-19) are examples of zoonoses that have spread throughout the globe with such a significant impact on public health that the scientific community has been called for a rapid intervention in preventing and treating emerging infections. Vaccination is probably the most effective tool in helping the immune system to activate protective responses against pathogens, reducing morbidity and mortality, as proven by historical records. Under health emergency conditions, new and alternative approaches in vaccine design and development are imperative for a rapid and massive vaccination coverage, to manage a disease outbreak and curtail the epidemic spread. This review gives an update on the current vaccination strategies for some of the emerging/re-emerging viruses, and discusses challenges and hurdles to overcome for developing efficacious vaccines against future pathogens.
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MESH Headings
- Animals
- Antibody-Dependent Enhancement/immunology
- Betacoronavirus/immunology
- COVID-19
- COVID-19 Vaccines
- Communicable Diseases, Emerging/prevention & control
- Communicable Diseases, Emerging/virology
- Coronavirus Infections/immunology
- Coronavirus Infections/prevention & control
- Coronavirus Infections/therapy
- Coronavirus Infections/virology
- Cross Reactions/immunology
- Humans
- Immunization, Passive
- Pandemics/prevention & control
- Pneumonia, Viral/prevention & control
- Pneumonia, Viral/therapy
- Pneumonia, Viral/virology
- SARS-CoV-2
- Vaccination
- Vaccines, Attenuated/immunology
- Vaccines, DNA/immunology
- Vaccines, Inactivated/immunology
- Vaccines, Subunit/immunology
- Viral Vaccines/immunology
- COVID-19 Serotherapy
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Affiliation(s)
- Maria Trovato
- Institute of Biochemistry and Cell Biology, National Research Council, Naples, Italy
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Li N, Zhang ZR, Zhang YN, Liu J, Deng CL, Shi PY, Yuan ZM, Ye HQ, Zhang B. A replication-defective Japanese encephalitis virus (JEV) vaccine candidate with NS1 deletion confers dual protection against JEV and West Nile virus in mice. NPJ Vaccines 2020; 5:73. [PMID: 32802412 PMCID: PMC7406499 DOI: 10.1038/s41541-020-00220-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2020] [Accepted: 07/14/2020] [Indexed: 11/09/2022] Open
Abstract
In our previous study, we have demonstrated in the context of WNV-ΔNS1 vaccine (a replication-defective West Nile virus (WNV) lacking NS1) that the NS1 trans-complementation system may offer a promising platform for the development of safe and efficient flavivirus vaccines only requiring one dose. Here, we produced high titer (107 IU/ml) replication-defective Japanese encephalitis virus (JEV) with NS1 deletion (JEV-ΔNS1) in the BHK-21 cell line stably expressing NS1 (BHKNS1) using the same strategy. JEV-ΔNS1 appeared safe with a remarkable genetic stability and high degrees of attenuation of in vivo neuroinvasiveness and neurovirulence. Meanwhile, it was demonstrated to be highly immunogenic in mice after a single dose, providing similar degrees of protection to SA14-14-2 vaccine (a most widely used live attenuated JEV vaccine), with healthy condition, undetectable viremia and gradually rising body weight. Importantly, we also found JEV-ΔNS1 induced robust cross-protective immune responses against the challenge of heterologous West Nile virus (WNV), another important member in the same JEV serocomplex, accounting for up to 80% survival rate following a single dose of immunization relative to mock-vaccinated mice. These results not only support the identification of the NS1-deleted flavivirus vaccines with a satisfied balance between safety and efficacy, but also demonstrate the potential of the JEV-ΔNS1 as an alternative vaccine candidate against both JEV and WNV challenge.
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Affiliation(s)
- Na Li
- Key Laboratory of Special Pathogens and Biosafety, Wuhan Institute of Virology, Center for Biosafety Mega-Science, Chinese Academy of Sciences, Wuhan, China.,University of Chinese Academy of Sciences, 100049 Beijing, China
| | - Zhe-Rui Zhang
- Key Laboratory of Special Pathogens and Biosafety, Wuhan Institute of Virology, Center for Biosafety Mega-Science, Chinese Academy of Sciences, Wuhan, China.,University of Chinese Academy of Sciences, 100049 Beijing, China
| | - Ya-Nan Zhang
- Key Laboratory of Special Pathogens and Biosafety, Wuhan Institute of Virology, Center for Biosafety Mega-Science, Chinese Academy of Sciences, Wuhan, China.,University of Chinese Academy of Sciences, 100049 Beijing, China
| | - Jing Liu
- Key Laboratory of Special Pathogens and Biosafety, Wuhan Institute of Virology, Center for Biosafety Mega-Science, Chinese Academy of Sciences, Wuhan, China.,University of Chinese Academy of Sciences, 100049 Beijing, China
| | - Cheng-Lin Deng
- Key Laboratory of Special Pathogens and Biosafety, Wuhan Institute of Virology, Center for Biosafety Mega-Science, Chinese Academy of Sciences, Wuhan, China
| | - Pei-Yong Shi
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, TX 77555 USA
| | - Zhi-Ming Yuan
- Key Laboratory of Special Pathogens and Biosafety, Wuhan Institute of Virology, Center for Biosafety Mega-Science, Chinese Academy of Sciences, Wuhan, China
| | - Han-Qing Ye
- Key Laboratory of Special Pathogens and Biosafety, Wuhan Institute of Virology, Center for Biosafety Mega-Science, Chinese Academy of Sciences, Wuhan, China
| | - Bo Zhang
- Key Laboratory of Special Pathogens and Biosafety, Wuhan Institute of Virology, Center for Biosafety Mega-Science, Chinese Academy of Sciences, Wuhan, China.,Drug Discovery Center for Infectious Disease, Nankai University, 300350 Tianjin, China
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Kaiser JA, Barrett ADT. Twenty Years of Progress Toward West Nile Virus Vaccine Development. Viruses 2019; 11:E823. [PMID: 31491885 PMCID: PMC6784102 DOI: 10.3390/v11090823] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Revised: 08/26/2019] [Accepted: 08/27/2019] [Indexed: 12/14/2022] Open
Abstract
Although West Nile virus (WNV) has been a prominent mosquito-transmitted infection in North America for twenty years, no human vaccine has been licensed. With a cumulative number of 24,714 neurological disease cases and 2314 deaths in the U.S. since 1999, plus a large outbreak in Europe in 2018 involving over 2000 human cases in 15 countries, a vaccine is essential to prevent continued morbidity, mortality, and economic burden. Currently, four veterinary vaccines are licensed, and six vaccines have progressed into clinical trials in humans. All four veterinary vaccines require multiple primary doses and annual boosters, but for a human vaccine to be protective and cost effective in the most vulnerable older age population, it is ideal that the vaccine be strongly immunogenic with only a single dose and without subsequent annual boosters. Of six human vaccine candidates, the two live, attenuated vaccines were the only ones that elicited strong immunity after a single dose. As none of these candidates have yet progressed beyond phase II clinical trials, development of new candidate vaccines and improvement of vaccination strategies remains an important area of research.
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Affiliation(s)
- Jaclyn A Kaiser
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, TX 77555, USA
| | - Alan D T Barrett
- Department of Pathology, University of Texas Medical Branch, Galveston, TX 77555, USA.
- Sealy Institute for Vaccine Sciences, University of Texas Medical Branch, Galveston, TX 77555, USA.
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