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Lee AR, Kim SH, Hong SY, Lee SH, Oh JS, Lee KY, Kim SJ, Ishikawa T, Shim SM, Lee HI, Seo SU. Characterization of genotype V Japanese encephalitis virus isolates from Republic of Korea. Emerg Microbes Infect 2024; 13:2362392. [PMID: 38808613 DOI: 10.1080/22221751.2024.2362392] [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] [Received: 03/13/2024] [Accepted: 05/27/2024] [Indexed: 05/30/2024]
Abstract
Japanese encephalitis (JE), caused by the Japanese encephalitis virus (JEV) infection, continues to pose significant public health challenges worldwide despite efficient vaccines. The virus is classified into five genotypes, among which genotype V (GV) was not detected for a long period after its initial isolation in 1952, until reports emerged from China and the Republic of Korea (ROK) since 2009. The characteristics of the virus are crucial in estimating its potential epidemiological impact. However, characterization of GV JEVs has so far been limited to two strains: Muar, the original isolate, and XZ0934, isolated in China. Two additional ROK GV JEV isolates, NCCP 43279 and NCCP 43413, are currently available, but their characteristics have not been explored. Our phylogenetic analysis revealed that GV virus sequences from the ROK segregate into two clades. NCCP 43279 and NCCP 43413 belong to different clades and exhibit distinct in vitro phenotypes. NCCP 43279 forms larger plaques but demonstrates inefficient propagation in cell culture compared to NCCP 43413. In vivo, NCCP 43279 induces higher morbidity and mortality in mice than NCCP 43413. Notably, NCCP 43279 shows more severe blood-brain barrier damage, suggesting superior brain invasion capabilities. Consistent with its higher virulence, NCCP 43279 displays more pronounced histopathological and immunopathological outcomes. In conclusion, our study confirms that the two ROK isolates are not only classified into different clades but also exhibit distinct in vitro and in vivo characteristics.
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Affiliation(s)
- Ah-Ra Lee
- Department of Biomedicine & Health Sciences, Graduate School, The Catholic University of Korea, Seoul, Republic of Korea
- Department of Microbiology, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea
| | - Sang-Hyun Kim
- Department of Biomedicine & Health Sciences, Graduate School, The Catholic University of Korea, Seoul, Republic of Korea
- Department of Microbiology, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea
| | - Su-Yeon Hong
- Department of Biomedicine & Health Sciences, Graduate School, The Catholic University of Korea, Seoul, Republic of Korea
- Department of Microbiology, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea
| | - Sang-Ho Lee
- Department of Biomedicine & Health Sciences, Graduate School, The Catholic University of Korea, Seoul, Republic of Korea
- Department of Microbiology, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea
| | - Jae Sang Oh
- Department of Neurosurgery, Uijeongbu St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea
| | - Kyung Yong Lee
- Division of Cancer Biology, Research Institute, National Cancer Center, Goyang, Republic of Korea
| | - Seong-Jun Kim
- Center for Infectious Disease Vaccine and Diagnosis Innovation (CEVI), Korea Research Institute of Chemical Technology, Daejeon, Republic of Korea
| | - Tomohiro Ishikawa
- Department of Microbiology, Dokkyo Medical University School of Medicine, Tochigi, Japan
| | - Sang-Mu Shim
- Division of Acute Virus Diseases, Korea National Institute of Health, Korea Disease Control and Prevention Agency, Cheongju, Republic of Korea
| | - Hee Il Lee
- Division of Vectors and Parasitic Diseases, Korea Disease Control and Prevention Agency, Cheongju, Republic of Korea
| | - Sang-Uk Seo
- Department of Biomedicine & Health Sciences, Graduate School, The Catholic University of Korea, Seoul, Republic of Korea
- Department of Microbiology, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea
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Fan YC, Chen JM, Chen YY, Ke YD, Chang GJJ, Chiou SS. Epitope(s) involving amino acids of the fusion loop of Japanese encephalitis virus envelope protein is(are) important to elicit protective immunity. J Virol 2024; 98:e0177323. [PMID: 38530012 PMCID: PMC11019926 DOI: 10.1128/jvi.01773-23] [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: 11/13/2023] [Accepted: 03/06/2024] [Indexed: 03/27/2024] Open
Abstract
Dengue vaccine candidates have been shown to improve vaccine safety and efficacy by altering the residues or accessibility of the fusion loop on the virus envelope protein domain II (DIIFL) in an ex vivo animal study. The current study aimed to comprehensively investigate the impact of DIIFL mutations on the antigenicity, immunogenicity, and protective efficacy of Japanese encephalitis virus (JEV) virus-like particles (VLPs) in mice. We found the DIIFL G106K/L107D (KD) and W101G/G106K/L107D (GKD) mutations altered the binding activity of JEV VLP to cross-reactive monoclonal antibodies but had no effect on their ability to elicit total IgG antibodies in mice. However, JEV VLPs with KD or GKD mutations induced significantly less neutralizing antibodies against JEV. Only 46% and 31% of the KD and GKD VLPs-immunized mice survived compared to 100% of the wild-type (WT) VLP-immunized mice after a lethal JEV challenge. In passive protection experiments, naïve mice that received sera from WT VLP-immunized mice exhibited a significantly higher survival rate of 46.7% compared to those receiving sera from KD VLP- and GKD VLP-immunized mice (6.7% and 0%, respectively). This study demonstrated that JEV DIIFL is crucial for eliciting potently neutralizing antibodies and protective immunity against JEV. IMPORTANCE Introduction of mutations into the fusion loop is one potential strategy for generating safe dengue and Zika vaccines by reducing the risk of severe dengue following subsequent infections, and for constructing live-attenuated vaccine candidates against newly emerging Japanese encephalitis virus (JEV) or Japanese encephalitis (JE) serocomplex virus. The monoclonal antibody studies indicated the fusion loop of JE serocomplex viruses primarily comprised non-neutralizing epitopes. However, the present study demonstrates that the JEV fusion loop plays a critical role in eliciting protective immunity in mice. Modifications to the fusion loop of JE serocomplex viruses might negatively affect vaccine efficacy compared to dengue and zika serocomplex viruses. Further studies are required to assess the impact of mutant fusion loop encoded by commonly used JEV vaccine strains on vaccine efficacy or safety after subsequent dengue virus infection.
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Affiliation(s)
- Yi-Chin Fan
- Institute of Epidemiology and Preventive Medicine, College of Public Health, National Taiwan University, Taipei, Taiwan
- Master of Public Health Degree Program, College of Public Health, National Taiwan University, Taipei, Taiwan
| | - Jo-Mei Chen
- Graduate Institute of Microbiology and Public Health, College of Veterinary Medicine, National Chung Hsing University, Taichung, Taiwan
| | - Yi-Ying Chen
- Graduate Institute of Microbiology and Public Health, College of Veterinary Medicine, National Chung Hsing University, Taichung, Taiwan
| | - Yuan-Dun Ke
- Institute of Epidemiology and Preventive Medicine, College of Public Health, National Taiwan University, Taipei, Taiwan
| | - Gwong-Jen J. Chang
- Arboviral Diseases Branch, Centers for Disease Control and Prevention, Fort, Fort Collins, Colorado, USA
| | - Shyan-Song Chiou
- Graduate Institute of Microbiology and Public Health, College of Veterinary Medicine, National Chung Hsing University, Taichung, Taiwan
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Pinapati KK, Tandon R, Tripathi P, Srivastava N. Recent advances to overcome the burden of Japanese encephalitis: A zoonotic infection with problematic early detection. Rev Med Virol 2023; 33:e2383. [PMID: 35983697 DOI: 10.1002/rmv.2383] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2022] [Revised: 07/21/2022] [Accepted: 07/29/2022] [Indexed: 01/28/2023]
Abstract
Japanese encephalitis (JE) is a vector-borne neurotropic disease caused by Japanese encephalitis virus (JEV) associated with high mortality rate distributed from Eastern and Southern Asia to Northern Queensland (Australia). The challenges in early detection and lack of point-of-care biomarkers make it the most important Flavivirus causing encephalitis. There is no specific treatment for the disease, although vaccines are licenced. In this review, we focussed on point-of-care biomarkers as early detection tools and developing the effective therapeutic agents that could halt JE. We have also provided molecular details of JEV, disease progression, and its pathogenesis with recent findings which might bring insights to overcome the disease burden.
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Affiliation(s)
- Kishore Kumar Pinapati
- Department of Biotechnology, National Institute of Pharmaceutical Education and Research-Raebareli (NIPER-R), Lucknow, Uttra Pradesh, India
| | - Reetika Tandon
- Department of Biotechnology, National Institute of Pharmaceutical Education and Research-Raebareli (NIPER-R), Lucknow, Uttra Pradesh, India
| | - Pratima Tripathi
- Department of Biotechnology, National Institute of Pharmaceutical Education and Research-Raebareli (NIPER-R), Lucknow, Uttra Pradesh, India
| | - Nidhi Srivastava
- Department of Biotechnology, National Institute of Pharmaceutical Education and Research-Raebareli (NIPER-R), Lucknow, Uttra Pradesh, India
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Lee AR, Song JM, Seo SU. Emerging Japanese Encephalitis Virus Genotype V in Republic of Korea. J Microbiol Biotechnol 2022; 32:955-959. [PMID: 35879275 PMCID: PMC9628952 DOI: 10.4014/jmb.2207.07002] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2022] [Revised: 07/20/2022] [Accepted: 07/21/2022] [Indexed: 12/15/2022]
Abstract
Japanese encephalitis (JE) is a vaccine-preventable mosquito-borne disease caused by infection with the Japanese encephalitis virus (JEV). JEV has five genotypes, including genotype V (GV), which is considered ancestral to the other genotypes. The first GV strain, GV Muar, was isolated from a Malayan patient in 1952 and GV did not reappear for 57 years until GV XZ0934 was isolated from a mosquito sample in China. Since 2010, 21 GV strains have been identified in Republic of Korea (ROK). Both GV Muar and GV XZ0934 are more pathogenic than other GI/GIII strains and are serologically distinct. However, because the ROK's GV strains have not been experimentally tested, their characteristics are not known. Characterization of the ROK's isolates is needed to enable development of effective GV strain-based vaccines to protect against GV infections.
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Affiliation(s)
- Ah-Ra Lee
- Department of Biomedicine and Health Sciences, Department of Microbiology, College of Medicine, The Catholic University of Korea, Seoul 06591, Republic of Korea
| | - Jae Min Song
- School of Biopharmaceutical and Medical Sciences, Sungshin Women’s University, Seoul 01133, Republic of Korea
| | - Sang-Uk Seo
- Department of Biomedicine and Health Sciences, Department of Microbiology, College of Medicine, The Catholic University of Korea, Seoul 06591, Republic of Korea,Corresponding author Phone: +82-2-2258-7355 Fax: +82-2-2258-8969 E-mail:
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Islam N, Xu C, Lau CL, Mills DJ, Clark J, Devine GJ, Hugo LE, Gyawali N, Thalib L, Furuya-Kanamori L. Persistence of antibodies, boostability, and interchangeability of Japanese encephalitis vaccines: A systematic review and dose-response meta-analysis. Vaccine 2022; 40:3546-3555. [PMID: 35568587 DOI: 10.1016/j.vaccine.2022.04.079] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2021] [Revised: 04/06/2022] [Accepted: 04/25/2022] [Indexed: 10/18/2022]
Abstract
BACKGROUND The burden of Japanese encephalitis (JE) is substantial and is arguably one of the most serious viral encephalitic diseases with high case fatality and no specific treatment. JE vaccines are the only available mean to prevent the disease; however, the long-term persistence of antibodies, boostability, and interchangeability between different vaccine classes are not well understood. METHODS To summarise the evidence, PubMed, Embase, and Cochrane CENTRAL were systematically searched from their inception to March 2021. Dose-response meta-analysis was utilised to synthesise the proportion of individuals who were seropositive over time after a primary vaccination course and a booster dose. Proportion meta-analysis was conducted to estimate the proportion of individuals who were seropositive as well as those who reported adverse events following a booster dose with a different vaccine class. RESULTS Of 1053 publications retrieved, 27 studies with 4,558 participants were included. Of these, 11 studies assessed persistence of antibodies, 14 studies boostability, and 8 vaccine class interchangeability. The pooled seropositivity, 1-year after primary vaccination was 83.4% (95 %CI 78.2-89.5%) and remained stable for up to 5 years (82.7%; 95 %CI 76.1-89.4%). Rapid anamnestic response was observed 10 days post-booster dose, the proportion of individuals who were seropositive reached 96.9% (95 %CI 95.9-97.8%) and remained > 95% for up to 6 years. Inactivated mouse brain-derived vaccines followed by a booster dose of a different vaccine class was effective (i.e. seropositive 99%) and well tolerated. CONCLUSIONS A booster dose after the primary vaccination is effective and further booster doses may be needed after 7 years. Inactivated mouse brain-derived vaccine followed by a booster with a newer vaccine class is effective and safe; although, there is a paucity of data related to newer classes of vaccines interchangeability.
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Affiliation(s)
- Nazmul Islam
- Department of Public Health, College of Health Sciences, QU Health, Qatar University, Doha, Qatar
| | - Chang Xu
- Ministry of Education, Key Laboratory for Population Health Across-Life Cycle, Anhui Medical University, Anhui, China
| | - Colleen L Lau
- School of Public Health, Faculty of Medicine, The University of Queensland, Herston, Australia; Dr Deb The Travel Doctor, Travel Medicine Alliance, Brisbane, Australia
| | - Deborah J Mills
- Dr Deb The Travel Doctor, Travel Medicine Alliance, Brisbane, Australia; Research School of Population Health, College of Health and Medicine, Australian National University, Canberra, Australia
| | - Justin Clark
- Institute for Evidence-Based Healthcare, Bond University, Robina, Australia
| | - Gregor J Devine
- Mosquito Control Laboratory, QIMR Berghofer Medical Research Institute, Brisbane, Australia
| | - Leon E Hugo
- Mosquito Control Laboratory, QIMR Berghofer Medical Research Institute, Brisbane, Australia
| | - Narayan Gyawali
- Mosquito Control Laboratory, QIMR Berghofer Medical Research Institute, Brisbane, Australia
| | - Lukman Thalib
- Department of Biostatistics, Faculty of Medicine, Istanbul Aydin University, Istanbul, Turkey
| | - Luis Furuya-Kanamori
- UQ Centre for Clinical Research, Faculty of Medicine, The University of Queensland, Herston, Australia.
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Effectiveness of Live-Attenuated Genotype III Japanese Encephalitis Viral Vaccine against Circulating Genotype I Viruses in Swine. Viruses 2022; 14:v14010114. [PMID: 35062317 PMCID: PMC8778556 DOI: 10.3390/v14010114] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2021] [Revised: 01/02/2022] [Accepted: 01/07/2022] [Indexed: 01/15/2023] Open
Abstract
Expansion of genotype I (GI) Japanese encephalitis viruses (JEV) has resulted in the replacement of the dominant genotype III (GIII) viruses, raising serious public health concerns for using GIII virus-derived vaccines to effectively control JEV epidemics. Therefore, this study used swine as the model to estimate the effectiveness of GIII live-attenuated vaccine against GI virus infection by comparing the incidence of stillbirth/abortion in gilts from vaccinated and non-vaccinated pig farms during the GI-circulation period. In total, 389 and 213 litters of gilts were recorded from four vaccinated and two non-vaccinated pig farms, respectively. All viruses detected in the aborted fetuses and mosquitoes belonged to the GI genotype during the study period. We thus estimated that the vaccine effectiveness of GIII live-attenuated vaccine against GI viruses in naive gilts based on the overall incidence of stillbirth/abortion and incidence of JEV-confirmed stillbirth/abortion was 65.5% (50.8–75.7%) and 74.7% (34.5–90.2%), respectively. In contrast to previous estimates, the GIII live-attenuated vaccine had an efficacy of 95.6% (68.3–99.4%) to prevent the incidence of stillbirth/abortion during the GIII-circulating period. These results indicate that the vaccine effectiveness of GIII live-attenuated JEV vaccine to prevent stillbirth/abortion caused by GI viruses is lower than that against GIII viruses.
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Furuya-Kanamori L, Xu C, Doi SAR, Clark J, Wangdi K, Mills DJ, Lau CL. Comparison of immunogenicity and safety of licensed Japanese encephalitis vaccines: A systematic review and network meta-analysis. Vaccine 2021; 39:4429-4436. [PMID: 34175128 DOI: 10.1016/j.vaccine.2021.06.023] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2021] [Revised: 06/06/2021] [Accepted: 06/08/2021] [Indexed: 12/28/2022]
Abstract
INTRODUCTION Annually more than 100,000 Japanese encephalitis (JE) cases and 25,000 deaths worldwide are caused by JE virus infection. More than 15 JE vaccines are currently in use worldwide. It is unknown whether any of the vaccines is superior to the others in terms of immunogenicity and safety. METHODS Four databases were systematically searched for randomised controlled trials that compared two or more types of JE vaccines. Vaccines were classified into four classes: inactivated mouse brain-derived (oldest class), inactivated Vero cell, live chimeric, and live attenuated. Network meta-analysis was used to generate mixed effect estimates against inactivated mouse brain-derived vaccines for seroconversion, and against placebo for adverse event (AE) and severe adverse event (SAE). RESULTS 23 studies (38,496 participants) were included. All newer vaccine classes had better immunogenicity, the difference was statistically significant for inactivated Vero cell (OR = 2.98; 95 %CI: 1.02-8.65) and live chimeric (OR = 5.93; 95 %CI: 1.73-20.32) vaccines. Inactivated mouse-derived vaccines had the highest odds for AEs (OR = 2.27; 95 %CI: 1.59-3.23), the odds of AE of newer vaccines was not different to placebo. There was no difference in SAEs across vaccine classes. CONCLUSIONS All newer JE vaccines have comparable safety profiles, live chimeric and inactivated Vero cell vaccines are the most immunogenic among the newer vaccine classes.
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Affiliation(s)
- Luis Furuya-Kanamori
- UQ Centre for Clinical Research, The University of Queensland, Herston, Australia.
| | - Chang Xu
- Department of Population Medicine, College of Medicine, QU Health, Qatar University, Doha, Qatar
| | - Suhail A R Doi
- Department of Population Medicine, College of Medicine, QU Health, Qatar University, Doha, Qatar
| | - Justin Clark
- Institute for Evidence-Based Healthcare, Bond University, Robina, Australia
| | - Kinley Wangdi
- Research School of Population Health, Australian National University, Canberra, Australia
| | - Deborah J Mills
- Research School of Population Health, Australian National University, Canberra, Australia; Dr Deb The Travel Doctor, Travel Medicine Alliance, Brisbane, Australia
| | - Colleen L Lau
- Research School of Population Health, Australian National University, Canberra, Australia; Dr Deb The Travel Doctor, Travel Medicine Alliance, Brisbane, Australia; School of Public Health, The University of Queensland, Herston, Australia
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Dey D, Poudyal S, Rehman A, Hasan SS. Structural and biochemical insights into flavivirus proteins. Virus Res 2021; 296:198343. [PMID: 33607183 DOI: 10.1016/j.virusres.2021.198343] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Revised: 02/10/2021] [Accepted: 02/11/2021] [Indexed: 01/01/2023]
Abstract
Flaviviruses are the fastest spreading arthropod-borne viruses that cause severe symptoms such as hepatitis, hemorrhagic fever, encephalitis, and congenital deformities. Nearly 40 % of the entire human population is at risk of flavivirus epidemics. Yet, effective vaccination is restricted only to a few flaviviruses such as yellow fever and Japanese encephalitis viruses, and most recently for select cases of dengue virus infections. Despite the global spread of dengue virus, and emergence of new threats such as Zika virus and a new genotype of Japanese encephalitis virus, insights into flavivirus targets for potentially broad-spectrum vaccination are limited. In this review article, we highlight biochemical and structural differences in flavivirus proteins critical for virus assembly and host interactions. A comparative sequence analysis of pH-responsive properties of viral structural proteins identifies trends in conservation of complementary acidic-basic character between interacting viral structural proteins. This is highly relevant to the understanding of pH-sensitive differences in virus assembly in organelles such as neutral ER and acidic Golgi. Surface residues in viral interfaces identified by structural approaches are shown to demonstrate partial conservation, further reinforcing virus-specificity in assembly and interactions with host proteins. A comparative analysis of epitope conservation in emerging flaviviruses identifies therapeutic antibody candidates that have potential as broad spectrum anti-virals, thus providing a path towards development of vaccines.
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Affiliation(s)
- Debajit Dey
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, 108 N. Greene Street, Baltimore MD 21201, USA
| | - Shishir Poudyal
- Department of Biological Sciences, Purdue University, 915 W. State Street, West Lafayette IN 47907, USA
| | - Asma Rehman
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, 108 N. Greene Street, Baltimore MD 21201, USA
| | - S Saif Hasan
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, 108 N. Greene Street, Baltimore MD 21201, USA; University of Maryland Marlene and Stewart Greenebaum Cancer Center, University of Maryland Medical Center, 22. S. Greene St. Baltimore MD 21201, USA; Center for Biomolecular Therapeutics, University of Maryland School of Medicine, 9600 Gudelsky Drive, Rockville MD 20850, USA.
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Abstract
Purpose of review As an eminently vaccine-preventable disease, encephalitis caused by Japanese encephalitis virus (JEV) has attracted an unusually high degree of attention from those seeking to develop viral vaccines. Since the 1950s, all types of JEV vaccines including inactivated, recombinant and live attenuated ones have been licensed. As an example of an extremely successful endeavour, the time is ripe for reviewing the development of JEV vaccines and probing the reasons behind their uniform success. Recent findings Vaccines against JEV have come a long way since the first licensing in the mid-1950s of the mouse brain-grown-inactivated virus preparations, to the present day live-attenuated virus vaccines. A survey of the various inactivated and live vaccines developed against JEV provides a striking insight into the impressive safety and efficacy of all the vaccines available to prevent encephalitis from JEV. This review juxtaposes studies to understand naturally acquired immunity against JEV that have mostly been published post-2000, compares these with those elicited by vaccines and highlights the paucity of data on cell-mediated immune responses elicited by JEV vaccines. Summary This article not only seeks to make available the immense salient literature on this endeavour in one collection, but also queries the basis for the remarkable success of JEV vaccines, not least of which may be the ease of protecting against encephalitis caused by JEV. To conclude, the true test of the ingenuity of those dedicated to the pursuit of viral vaccines would be success against viral diseases such as HIV-AIDS and dengue that pose a far greater challenge to scientists.
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Affiliation(s)
- Vijaya Satchidanandam
- Room SA07, Biology Building, Department of Microbiology and Cell Biology, Indian Institute of Science, Sir C.V. Raman Avenue, Bangalore, Karnataka 560012 India
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Immune response at 12-23 months following a single dose of Vero cell culture-derived Japanese encephalitis (JE) vaccine in adults previously vaccinated with mouse brain-derived JE vaccine. Vaccine 2020; 38:6899-6903. [PMID: 32907756 DOI: 10.1016/j.vaccine.2020.08.061] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2020] [Revised: 08/03/2020] [Accepted: 08/25/2020] [Indexed: 12/19/2022]
Abstract
BACKGROUND Japanese encephalitis (JE) virus is an important cause of neurological disease in Asia. JE vaccine is recommended for travelers with higher JE risk itineraries. Inactivated Vero cell culture-derived JE vaccine (JE-VC) is the only JE vaccine currently available in the United States. An inactivated mouse brain-derived JE vaccine (JE-MB) previously was available but production was discontinued. One JE-VC dose administered to adults previously vaccinated with ≥3 doses of JE-MB provides good short-term protection for at least one month, but data on longer-term protection are limited. We evaluated non-inferiority of the JE virus neutralizing antibody response at 12-23 months in JE-MB-vaccinated adults administered one JE-VC dose compared with JE vaccine-naïve adults administered a JE-VC two-dose primary series. METHODS We obtained archived sera from U.S. military personnel and performed a 50% plaque reduction neutralization test for anti-JE virus neutralizing antibodies. We compared the geometric mean titer (GMT) and seroprotection rate at 12-23 months after one JE-VC dose in previously JE-MB-vaccinated personnel and after the second JE-VC dose in previously JE vaccine-naïve personnel. Non-inferiority was concluded if the lower bound of the two-sided 95% confidence interval (CI) of the GMT ratio in previously vaccinated to vaccine-naïve personnel was >1/1.5. RESULTS The GMT in previously JE-MB-vaccinated persons was 75 (95% CI 63-90) and in previously JE vaccine-naïve persons was 12 (95% CI 11-14), and seroprotection rates were 94% (235/250) and 54% (135/250), respectively. The ratio of GMTs was 6.3 (95% CI: 5.0-7.7), satisfying the criterion for non-inferiority. CONCLUSIONS One JE-VC dose in previously JE-MB-vaccinated military personnel provides good protection for at least 1-2 years. The benefits of administration of a single JE-VC dose in previously JE-MB-vaccinated adults include a shorter time to completion of re-vaccination before travel, a decrease in the risk of adverse events, and reduced costs.
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Kling K, Harder T, Younger Z, Burchard G, Schmidt-Chanasit J, Wichmann O. Vaccination against Japanese encephalitis with IC51: systematic review on immunogenicity, duration of protection and safety. J Travel Med 2020; 27:5732465. [PMID: 32043122 DOI: 10.1093/jtm/taaa016] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/02/2019] [Revised: 01/28/2020] [Indexed: 01/04/2023]
Abstract
Japanese encephalitis is a disease caused by a flavivirus which is transmitted by mosquitos in endemic countries. Considering the potentially severe outcomes of the disease, vaccination is recommended for those at risk of exposure. During recent years, IC51 (IXIARO®, JESPECT®, JEVAL®) has increasingly been used to protect travellers from Europe and the USA. However, no systematic review exists that summarizes the currently available evidence on the immunogenicity and safety of this vaccine. We conducted a systematic review on the immunogenicity and safety of IC51, using the databases PubMed, MEDLINE, EMBASE and ClinicalTrials.gov (search date: 31 August 2019). Data extracted from included studies were grouped by outcomes and stratified by population and setting. Risk of bias (ROB) was assessed using the RoB 2 tool for randomized controlled trials (RCTs) and ROBINS-I for non-randomized studies. Due to high heterogeneity, meta-analysis was not performed. A total of 32 studies from 16 countries met the inclusion criteria (15 RCTs, 17 non-randomized studies). ROB was serious or high in the majority of studies. Seroprotection rates ranged from 93 to 100% in adults (seven studies) and from 91 to 100% in children (four studies). In the study involving adults aged 64 years and older, seroprotection was 65% with higher rates in persons who were previously vaccinated against tick-borne encephalitis virus. Safety was investigated in 27 studies. Rates of serious adverse events were below 5% in all age groups, with the majority not being causally related to the vaccine. IC51 is a safe vaccine with good seroprotective abilities in persons aged >2 months to <64 years. The body of evidence, however, is weakened by a large amount of heterogeneity in study and clinical trial methodology. Further well-designed RCTs with special risk groups are needed.
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Affiliation(s)
- Kerstin Kling
- Immunization Unit, Robert Koch Institute, Berlin 13353, Germany
| | - Thomas Harder
- Immunization Unit, Robert Koch Institute, Berlin 13353, Germany
| | - Zane Younger
- Immunization Unit, Robert Koch Institute, Berlin 13353, Germany
| | - Gerd Burchard
- Bernhard-Nocht-Institute for Tropical Medicine, Hamburg 20359, Germany
| | - Jonas Schmidt-Chanasit
- Bernhard-Nocht-Institute for Tropical Medicine, Hamburg 20359, Germany
- Faculty of Mathematics, Informatics and Natural Sciences, Universität Hamburg, Hamburg 22609, Germany
| | - Ole Wichmann
- Immunization Unit, Robert Koch Institute, Berlin 13353, Germany
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Abstract
Japanese encephalitis is a mosquito-borne disease that occurs in Asia and is caused by Japanese encephalitis virus (JEV), a member of the genus Flavivirus. Although many flaviviruses can cause encephalitis, JEV causes particularly severe neurological manifestations. The virus causes loss of more disability-adjusted life years than any other arthropod-borne virus owing to the frequent neurological sequelae of the condition. Despite substantial advances in our understanding of Japanese encephalitis from in vitro studies and animal models, studies of pathogenesis and treatment in humans are lagging behind. Few mechanistic studies have been conducted in humans, and only four clinical trials of therapies for Japanese encephalitis have taken place in the past 10 years despite an estimated incidence of 69,000 cases per year. Previous trials for Japanese encephalitis might have been too small to detect important benefits of potential treatments. Many potential treatment targets exist for Japanese encephalitis, and pathogenesis and virological studies have uncovered mechanisms by which these drugs could work. In this Review, we summarize the epidemiology, clinical features, prevention and treatment of Japanese encephalitis and focus on potential new therapeutic strategies, based on repurposing existing compounds that are already suitable for human use and could be trialled without delay. We use our newly improved understanding of Japanese encephalitis pathogenesis to posit potential treatments and outline some of the many challenges that remain in tackling the disease in humans.
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Hills SL, Walter EB, Atmar RL, Fischer M. Japanese Encephalitis Vaccine: Recommendations of the Advisory Committee on Immunization Practices. MMWR Recomm Rep 2019; 68:1-33. [PMID: 31518342 PMCID: PMC6659993 DOI: 10.15585/mmwr.rr6802a1] [Citation(s) in RCA: 54] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
This report updates the 2010 recommendations from the CDC Advisory Committee on Immunization Practices (ACIP) regarding prevention of Japanese encephalitis (JE) among U.S. travelers and laboratory workers (Fischer M, Lindsey N, Staples JE, Hills S. Japanese encephalitis vaccines: recommendations of the Advisory Committee on Immunization Practices (ACIP). MMWR Recomm Rep 2010;59[No. RR-1]). The report summarizes the epidemiology of JE, describes the JE vaccine that is licensed and available in the United States, and provides recommendations for its use among travelers and laboratory workers.JE virus, a mosquitoborne flavivirus, is the most common vaccine-preventable cause of encephalitis in Asia. JE occurs throughout most of Asia and parts of the western Pacific. Approximately 20%-30% of patients die, and 30%-50% of survivors have neurologic, cognitive, or behavioral sequelae. No antiviral treatment is available.Inactivated Vero cell culture-derived JE vaccine (Ixiaro [JE-VC]) is the only JE vaccine that is licensed and available in the United States. In 2009, the U.S. Food and Drug Administration (FDA) licensed JE-VC for use in persons aged ≥17 years; in 2013, licensure was extended to include children aged ≥2 months.Most travelers to countries where the disease is endemic are at very low risk for JE. However, some travelers are at increased risk for infection on the basis of their travel plans. Factors that increase the risk for JE virus exposure include 1) traveling for a longer period; 2) travel during the JE virus transmission season; 3) spending time in rural areas; 4) participating in extensive outdoor activities; and 5) staying in accommodations without air conditioning, screens, or bed nets. All travelers to countries where JE is endemic should be advised to take precautions to avoid mosquito bites to reduce the risk for JE and other vectorborne diseases. For some persons who might be at increased risk for JE, the vaccine can further reduce the risk for infection. The decision about whether to vaccinate should be individualized and consider the 1) risks related to the specific travel itinerary, 2) likelihood of future travel to countries where JE is endemic, 3) high morbidity and mortality of JE, 4) availability of an effective vaccine, 5) possibility (but low probability) of serious adverse events after vaccination, and 6) the traveler's personal perception and tolerance of risk.JE vaccine is recommended for persons moving to a JE-endemic country to take up residence, longer-term (e.g., ≥1 month) travelers to JE-endemic areas, and frequent travelers to JE-endemic areas. JE vaccine also should be considered for shorter-term (e.g., <1 month) travelers with an increased risk for JE on the basis of planned travel duration, season, location, activities, and accommodations and for travelers to JE-endemic areas who are uncertain about their specific travel duration, destinations, or activities. JE vaccine is not recommended for travelers with very low-risk itineraries, such as shorter-term travel limited to urban areas or outside of a well-defined JE virus transmission season.
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Experimental Evaluation of the Role of Ecologically-Relevant Hosts and Vectors in Japanese Encephalitis Virus Genotype Displacement. Viruses 2019; 11:v11010032. [PMID: 30621345 PMCID: PMC6356879 DOI: 10.3390/v11010032] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2018] [Revised: 12/23/2018] [Accepted: 01/04/2019] [Indexed: 12/29/2022] Open
Abstract
Japanese encephalitis virus (JEV) is a flavivirus that is maintained via transmission between Culex spp. mosquitoes and water birds across a large swath of southern Asia and northern Australia. Currently JEV is the leading cause of vaccine-preventable encephalitis in humans in Asia. Five genotypes of JEV (G-I–G-V) have been responsible for historical and current outbreaks in endemic regions, and G-I and G-III co-circulate throughout Southern Asia. While G-III has historically been the dominant genotype worldwide, G-I has gradually but steadily displaced G-III. The objective of this study was to better understand the phenomenon of genotype displacement for JEV by evaluating both avian host and mosquito vector susceptibilities to infection with representatives from both G-I and G-III. Since ducks and Culex quinquefasciatus mosquitoes are prevalent avian hosts and vectors perpetuating JEV transmission in JE endemic areas, experimental evaluation of virus replication in these species was considered to approximate the natural conditions necessary for studying the role of host, vectors and viral fitness in the JEV genotype displacement context. We evaluated viremia in ducklings infected with G-I and G-III, and did not detect differences in magnitude or duration of viremia. Testing the same viruses in mosquitoes revealed that the rates of infection, dissemination and transmission were higher in virus strains belonging to G-I than G-III, and that the extrinsic incubation period was shorter for the G-I strains. These data suggest that the characteristics of JEV infection of mosquitoes but not of ducklings, may have play a role in genotype displacement.
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Fan YC, Chen JM, Lin JW, Chen YY, Wu GH, Su KH, Chiou MT, Wu SR, Yin JH, Liao JW, Chang GJJ, Chiou SS. Genotype I of Japanese Encephalitis Virus Virus-like Particles Elicit Sterilizing Immunity against Genotype I and III Viral Challenge in Swine. Sci Rep 2018; 8:7481. [PMID: 29748549 PMCID: PMC5945781 DOI: 10.1038/s41598-018-25596-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2017] [Accepted: 03/21/2018] [Indexed: 01/04/2023] Open
Abstract
Swine are a critical amplifying host involved in human Japanese encephalitis (JE) outbreaks. Cross-genotypic immunogenicity and sterile protection are important for the current genotype III (GIII) virus-derived vaccines in swine, especially now that emerging genotype I (GI) JE virus (JEV) has replaced GIII virus as the dominant strain. Herein, we aimed to develop a system to generate GI JEV virus-like particles (VLPs) and evaluate the immunogenicity and protection of the GI vaccine candidate in mice and specific pathogen-free swine. A CHO-heparan sulfate-deficient (CHO-HS(-)) cell clone, named 51-10 clone, stably expressing GI-JEV VLP was selected and continually secreted GI VLPs without signs of cell fusion. 51-10 VLPs formed a homogeneously empty-particle morphology and exhibited similar antigenic activity as GI virus. GI VLP-immunized mice showed balanced cross-neutralizing antibody titers against GI to GIV viruses (50% focus-reduction micro-neutralization assay titers 71 to 240) as well as potent protection against GI or GIII virus infection. GI VLP-immunized swine challenged with GI or GIII viruses showed no fever, viremia, or viral RNA in tonsils, lymph nodes, and brains as compared with phosphate buffered saline-immunized swine. We thus conclude GI VLPs can provide sterile protection against GI and GIII viruses in swine.
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Affiliation(s)
- Yi-Chin Fan
- Graduate Institute of Microbiology and Public Health, National Chung Hsing University, Taichung, Taiwan
| | - Jo-Mei Chen
- Graduate Institute of Microbiology and Public Health, National Chung Hsing University, Taichung, Taiwan
| | - Jen-Wei Lin
- Graduate Institute of Microbiology and Public Health, National Chung Hsing University, Taichung, Taiwan
| | - Yi-Ying Chen
- Graduate Institute of Microbiology and Public Health, National Chung Hsing University, Taichung, Taiwan
| | - Guan-Hong Wu
- Graduate Institute of Microbiology and Public Health, National Chung Hsing University, Taichung, Taiwan
| | - Kuan-Hsuan Su
- Department of Veterinary Medicine, National Pingtung University of Science and Technology, Pingtung, Taiwan
| | - Ming-Tang Chiou
- Department of Veterinary Medicine, National Pingtung University of Science and Technology, Pingtung, Taiwan
| | - Shang-Rung Wu
- Institute of Oral Medicine, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Ji-Hang Yin
- Graduate Institute of Veterinary Pathobiology, National Chung Hsing University, Taichung, Taiwan
| | - Jiunn-Wang Liao
- Graduate Institute of Veterinary Pathobiology, National Chung Hsing University, Taichung, Taiwan
| | - Gwong-Jen J Chang
- Arboviral Diseases Branch, Center for Disease Control and Prevention, Fort Collins, Colorado, United States of America
| | - Shyan-Song Chiou
- Graduate Institute of Microbiology and Public Health, National Chung Hsing University, Taichung, Taiwan.
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Long-term immunogenicity of an initial booster dose of an inactivated, Vero cell culture-derived Japanese encephalitis vaccine (JE-VC) and the safety and immunogenicity of a second JE-VC booster dose in children previously vaccinated with an inactivated, mouse brain-derived Japanese encephalitis vaccine. Vaccine 2018; 36:1398-1404. [DOI: 10.1016/j.vaccine.2018.01.075] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2017] [Revised: 01/25/2018] [Accepted: 01/29/2018] [Indexed: 01/23/2023]
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Hegde NR, Gore MM. Japanese encephalitis vaccines: Immunogenicity, protective efficacy, effectiveness, and impact on the burden of disease. Hum Vaccin Immunother 2017; 13:1-18. [PMID: 28301270 DOI: 10.1080/21645515.2017.1285472] [Citation(s) in RCA: 97] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Japanese encephalitis (JE) is a serious public health concern in most of Asia. The disease is caused by JE virus (JEV), a flavivirus transmitted by Culex mosquitoes. Several vaccines have been developed to control JE in endemic areas as well as to protect travelers and military personnel who visit or are commissioned from non-endemic to endemic areas. The vaccines include inactivated vaccines produced in mouse brain or cell cultures, live attenuated vaccines, and a chimeric vaccine based on the live attenuated yellow fever virus 17D vaccine strain. All the marketed vaccines belong to the JEV genotype III, but have been shown to be efficacious against other genotypes and strains, with varying degrees of cross-neutralization, albeit at levels deemed to be protective. The protective responses have been shown to last three or more years, depending on the type of vaccine and the number of doses. This review presents a brief account of the different JE vaccines, their immunogenicity and protective ability, and the impact of JE vaccines in reducing the burden of disease in endemic countries.
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Affiliation(s)
- Nagendra R Hegde
- a Ella Foundation, Genome Valley , Turkapally, Shameerpet Mandal , Hyderabad , India
| | - Milind M Gore
- b National Institute of Virology, Indian Council of Medical Research , Pune , India
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Sharma P, Srivastav S, Mishra S, Kumar A. Sequence and Structure Based Binding Prediction Study of HLA Class I and cTAP Binding Peptides for Japanese Encephalitis Vaccine Development. Int J Pept Res Ther 2016. [DOI: 10.1007/s10989-016-9558-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Abstract
Japanese encephalitis virus, as the most important vaccine-preventable cause of viral encephalitis in Asia, is estimated to cause over 68,000 clinical cases yearly. In endemic areas, most Japanese encephalitis infections occur in children younger than 10 y and clinical manifestation of this disease is critical, because there is no effective treatment available. As JEV infections are regarded as one of the most serious viral causes of encephalitis and mass immunization programmes are generally recommended for residents in endemic areas, a safe and effective JEV vaccine was needed to protect them as well as others at risk. Due to the safety concerns with the mouse brain derived vaccine, second generation vaccines against JE produced in cell culture like Vero cells were developed. IXIARO® is a purified, inactivated aluminum-adjuvanted JE vaccine, based on the SA14-14-2 virus strain, and is available in North America, Europe, Canada, Switzerland, Singapore, Hong Kong and Israel as well as in Australia & New Zealand (as JESPECT®).The safety, tolerability and immunogenicity profile of IXIARO® is well established through a number of clinical studies comparing IXIARO® with placebo as well as mouse brain derived vaccine. Recent data show that the global incidence of JE remains substantial, especially young children in endemic areas are most susceptible. As vaccination is the most feasible, reliable and cost effective tool for JE control, IXIARO® with confirmed excellent safety profile is highly recommendable, in particular for vaccination of children at risk. The European Commission as well as the FDA approved the extension of indication of IXIARO® to the pediatric segment (2 months of age and older) based on these data.
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Affiliation(s)
- Christa Firbas
- a Department of Clinical Pharmacology; Medical University of Vienna ; Vienna , Austria
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Walker XJ, Barnett ED, Wilson ME, Macleod WB, Jentes ES, Karchmer AW, Hamer DH, Chen LH. Characteristics of Travelers to Asia Requiring Multidose Vaccine Schedules: Japanese Encephalitis and Rabies Prevention. J Travel Med 2015; 22:403-9. [PMID: 26420372 DOI: 10.1111/jtm.12237] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/10/2015] [Revised: 07/21/2015] [Accepted: 08/03/2015] [Indexed: 11/30/2022]
Abstract
BACKGROUND Japanese encephalitis (JE) and rabies are serious vaccine preventable diseases which are an important consideration for travelers to Asia. METHODS Five Boston-area travel clinics collected demographic data, trip information, and interventions for travelers to Asia seen at pre-travel consultations from March 1, 2008, through July 31, 2010. We evaluated travelers for proportion vaccinated for JE and rabies, those traveling for >1 month, and whether travelers had adequate time to complete the JE series (clinic visit ≥28 days before departure) and rabies pre-exposure prophylaxis (clinic visit ≥21 days before departure). RESULTS Among 15,440 travelers from five Boston Area Travel Medicine Network travel clinics, Asia was the most common destination region, visited by 5,582 (36%) of travelers. Among these travelers, 4,810 (86%) planned to travel to only one Asian subregion. Median trip duration was 17 days, with more than 20% traveling for >1 month. The most common destinations were South (41%), Southeast (26%), and East (23%) Asia. Of those traveling to South, Southeast, or East Asia, over one-third with trips >1 month had insufficient time to complete a series for either JE or rabies vaccine. Overall, only 10% of travelers were vaccinated (past and pre-travel visit) for either JE or rabies, with lowest percentages among travelers visiting friends and relatives. Most travelers received advice on vector precautions (96%) and rabies prevention, which included avoiding animal contact, washing wounds, and obtaining appropriate post-exposure prophylaxis (88%). CONCLUSION Given the insufficient time for completion and relatively low vaccination rates, greater awareness of earlier pre-travel consultations, at least 4-6 weeks before travel, and accurate risk assessment for travelers are important. Effective counseling about vector avoidance, rabies, and animal bite prevention and management remains critical.
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Affiliation(s)
- Xaviour J Walker
- Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA
| | - Elizabeth D Barnett
- Section of Pediatric Infectious Diseases, Boston Medical Center and Boston University School of Medicine, Boston, MA, USA
| | - Mary E Wilson
- Harvard T. H. Chan School of Public Health, Boston, MA, USA
| | - William B Macleod
- Center for Global Health and Development, Boston University School of Public Health, Boston, MA, USA
| | - Emily S Jentes
- Division of Global Migration and Quarantine, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Adolf W Karchmer
- Division of Infectious Diseases, Department of Medicine, Beth Israel Deaconess Medical Center, Boston, MA, USA.,Faculty of Medicine, Harvard Medical School, Boston, MA, USA
| | - Davidson H Hamer
- Center for Global Health and Development, Boston University School of Public Health, Boston, MA, USA.,Section of Infectious Diseases, Boston University School of Medicine, Boston, MA, USA
| | - Lin H Chen
- Faculty of Medicine, Harvard Medical School, Boston, MA, USA.,Department of Medicine, Mount Auburn Hospital, Cambridge, MA, USA
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de Wispelaere M, Ricklin M, Souque P, Frenkiel MP, Paulous S, Garcìa-Nicolàs O, Summerfield A, Charneau P, Desprès P. A Lentiviral Vector Expressing Japanese Encephalitis Virus-like Particles Elicits Broad Neutralizing Antibody Response in Pigs. PLoS Negl Trop Dis 2015; 9:e0004081. [PMID: 26437302 PMCID: PMC4593544 DOI: 10.1371/journal.pntd.0004081] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2015] [Accepted: 08/21/2015] [Indexed: 01/08/2023] Open
Abstract
Background Japanese encephalitis virus (JEV) is the major cause of viral encephalitis in Southeast Asia. Vaccination of domestic pigs has been suggested as a “one health” strategy to reduce viral disease transmission to humans. The efficiency of two lentiviral TRIP/JEV vectors expressing the JEV envelope prM and E glycoproteins at eliciting protective humoral response was assessed in a mouse model and piglets. Methodology/Principal Findings A gene encoding the envelope proteins prM and E from a genotype 3 JEV strain was inserted into a lentiviral TRIP vector. Two lentiviral vectors TRIP/JEV were generated, each expressing the prM signal peptide followed by the prM protein and the E glycoprotein, the latter being expressed either in its native form or lacking its two C-terminal transmembrane domains. In vitro transduction of cells with the TRIP/JEV vector expressing the native prM and E resulted in the efficient secretion of virus-like particles of Japanese encephalitis virus. Immunization of BALB/c mice with TRIP/JEV vectors resulted in the production of IgGs against Japanese encephalitis virus, and the injection of a second dose one month after the prime injection greatly boosted antibody titers. The TRIP/JEV vectors elicited neutralizing antibodies against JEV strains belonging to genotypes 1, 3, and 5. Immunization of piglets with two doses of the lentiviral vector expressing JEV virus-like particles led to high titers of anti-JEV antibodies, that had efficient neutralizing activity regardless of the JEV genotype tested. Conclusions/Significance Immunization of pigs with the lentiviral vector expressing JEV virus-like particles is particularly efficient to prime antigen-specific humoral immunity and trigger neutralizing antibody responses against JEV genotypes 1, 3, and 5. The titers of neutralizing antibodies elicited by the TRIP/JEV vector are sufficient to confer protection in domestic pigs against different genotypes of JEV and this could be of a great utility in endemic regions where more than one genotype is circulating. Japanese encephalitis virus is the etiologic agent of the most medically important viral encephalitis in South Asia with thousands of deaths per year. The virus is maintained in an enzootic cycle between Culex mosquitoes and amplifying vertebrate hosts, such as wild boars and pigs. Vaccination of domestic pigs has been suggested as a strategy to reduce viral disease transmission to humans, in line with the now-called “One Health” concept. Lentiviral gene transfer vectors represent a novel vaccination platform with an unprecedented ability to induce robust humoral immunity in various animal species. In our study, we demonstrated that immunization of pigs with a recombinant lentiviral vector expressing virus-like particles of Japanese encephalitis virus is particularly efficient at eliciting specific humoral immunity. The titers of neutralizing antibodies elicited by the lentiviral vector are sufficient to confer protection in domestic pigs against the different genotypes of Japanese encephalitis virus observed in Asia.
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Affiliation(s)
| | - Meret Ricklin
- Institute of Virology and Immunology, Mittelhäusern, Switzerland
| | - Philippe Souque
- Virologie Moléculaire et Vaccinologie, Institut Pasteur, Paris, France
| | | | - Sylvie Paulous
- Interactions Moléculaires Flavivirus-Hôtes, Institut Pasteur, Paris, France
| | | | - Artur Summerfield
- Institute of Virology and Immunology, Mittelhäusern, Switzerland
- Department of Infectious Diseases and Pathobiology, Vetsuisse Faculty, University of Bern, Bern, Switzerland
| | - Pierre Charneau
- Virologie Moléculaire et Vaccinologie, Institut Pasteur, Paris, France
- * E-mail: (PC); (PD)
| | - Philippe Desprès
- Interactions Moléculaires Flavivirus-Hôtes, Institut Pasteur, Paris, France
- * E-mail: (PC); (PD)
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Erra EO, Kantele A. The Vero cell-derived, inactivated, SA14-14-2 strain-based vaccine (Ixiaro) for prevention of Japanese encephalitis. Expert Rev Vaccines 2015; 14:1167-79. [PMID: 26162529 DOI: 10.1586/14760584.2015.1061939] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
With an estimated 68,000 cases each year, Japanese encephalitis (JE) is the leading cause of viral encephalitis in Asia. Vaccination against the disease is recommended for endemic populations and also for travelers at risk. Recently, a Vero cell-derived, inactivated, SA14-14-2 strain-based JE vaccine (JE-VC) became available for travelers from non-endemic regions, replacing the traditional mouse brain-derived vaccines. First licensed in 2009, JE-VC is currently available in Europe, the USA, Canada, Australia and several other countries. In 2013, the vaccine was approved by the European Medicines Agency and the US Food and Drug Administration for use in children. This review summarizes current data on the immunogenicity, safety and clinical use of JE-VC.
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Affiliation(s)
- Elina O Erra
- Haartman Institute, University of Helsinki, Helsinki, Finland
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23
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Tajima S, Yagasaki K, Kotaki A, Tomikawa T, Nakayama E, Moi ML, Lim CK, Saijo M, Kurane I, Takasaki T. In vitro growth, pathogenicity and serological characteristics of the Japanese encephalitis virus genotype V Muar strain. J Gen Virol 2015; 96:2661-2669. [PMID: 26048886 DOI: 10.1099/vir.0.000213] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
The characteristics of genotype V Japanese encephalitis virus (GV JEV) remain poorly understood as only two strains have been isolated to date. In this study, we examined the effects of the GV JEV Muar strain on in vitro growth and pathogenicity in mice; we also evaluated the efficacy of inactivated JEV vaccines against the Muar strain. Although growth of the Muar strain in mouse neuroblastoma N18 cells was clearly worse than that of the GIII Beijing-1 and GI Mie/41/2002 strains, neuroinvasiveness of the Muar strain was similar to that of the Beijing-1 strain and significantly higher than that of the Mie/41/2002 strain. The results of a plaque reduction neutralization test suggested that the neutralization ability of the JEV vaccines against the Muar strain was reduced compared with the GI and GIII strains. However, the protection potency of the JEV vaccine against the Muar strain was similar to that for the Beijing-1 strain in mice. Our data indicate that GV JEV has unique growth, virulence and antigenicity features.
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Affiliation(s)
- Shigeru Tajima
- Department of Virology I, National Institute of Infectious Diseases, 1-23-1 Toyama, Shinjuku, Tokyo 162-8640, Japan
| | - Kazumi Yagasaki
- Department of Virology I, National Institute of Infectious Diseases, 1-23-1 Toyama, Shinjuku, Tokyo 162-8640, Japan
| | - Akira Kotaki
- Department of Virology I, National Institute of Infectious Diseases, 1-23-1 Toyama, Shinjuku, Tokyo 162-8640, Japan
| | - Takumi Tomikawa
- Department of Virology I, National Institute of Infectious Diseases, 1-23-1 Toyama, Shinjuku, Tokyo 162-8640, Japan
| | - Eri Nakayama
- Department of Virology I, National Institute of Infectious Diseases, 1-23-1 Toyama, Shinjuku, Tokyo 162-8640, Japan
| | - Meng Ling Moi
- Department of Virology I, National Institute of Infectious Diseases, 1-23-1 Toyama, Shinjuku, Tokyo 162-8640, Japan
| | - Chang-Kweng Lim
- Department of Virology I, National Institute of Infectious Diseases, 1-23-1 Toyama, Shinjuku, Tokyo 162-8640, Japan
| | - Masayuki Saijo
- Department of Virology I, National Institute of Infectious Diseases, 1-23-1 Toyama, Shinjuku, Tokyo 162-8640, Japan
| | - Ichiro Kurane
- Department of Virology I, National Institute of Infectious Diseases, 1-23-1 Toyama, Shinjuku, Tokyo 162-8640, Japan
| | - Tomohiko Takasaki
- Department of Virology I, National Institute of Infectious Diseases, 1-23-1 Toyama, Shinjuku, Tokyo 162-8640, Japan
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Singh A, Mitra M, Sampath G, Venugopal P, Rao JV, Krishnamurthy B, Gupta MK, Sri Krishna S, Sudhakar B, Rao NB, Kaushik Y, Gopinathan K, Hegde NR, Gore MM, Krishna Mohan V, Ella KM. A Japanese Encephalitis Vaccine From India Induces Durable and Cross-protective Immunity Against Temporally and Spatially Wide-ranging Global Field Strains. J Infect Dis 2015; 212:715-25. [PMID: 25601942 DOI: 10.1093/infdis/jiv023] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2014] [Accepted: 01/06/2015] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Japanese encephalitis (JE) is a vaccine-preventable acute disease. We report the results of a phase 2/3 trial of JENVAC, a Vero cell-derived vaccine developed using an Indian strain of JE virus (JEV). METHODS JENVAC was administered in 2 doses 28 days apart, and immunogenicity was compared to that from a single dose of SA-14-14-2, the only approved JE vaccine and regimen at the time in India. RESULTS After both the doses, seroconversion and seroprotection were >90% for JENVAC. For SA-14-14-2, seroconversion and seroprotection were 57.69% and 77.56%, respectively, on day 28 and 39.74% and 60.26%, respectively, on day 56. The geometric mean titers at day 28 and day 56 were 145.04 and 460.53, respectively, for JENVAC and 38.56 and 25.29, respectively, for SA-14-14-2. With a single dose of JENVAC, seroprotection titers lasted at least 12 months in >80% of the subjects. Following receipt of 2 doses, 61.17% of subjects retained seroprotection titers at 24 months, and immunogenicity criteria were higher than that for SA-14-14-2 at 12, 18, and 24 months each. Sera from JENVAC subjects neutralized JEV genotypes I, II, III, and IV equally well. Adverse events were not significantly different between the 2 vaccines. CONCLUSIONS JENVAC elicits long-lasting, broadly protective immunity. CLINICAL TRIALS REGISTRATION CTRI/2011/07/001855.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | | | | | | | - Milind M Gore
- Gorakhpur Unit, National Institute of Virology, India
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Sharma P, Saxena K, Mishra S, Kumar A. A comprehensive analysis of predicted HLA binding peptides of JE viral proteins specific to north Indian isolates. Bioinformation 2014; 10:334-41. [PMID: 25097375 PMCID: PMC4110423 DOI: 10.6026/97320630010334] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2014] [Revised: 05/13/2014] [Accepted: 05/24/2014] [Indexed: 11/26/2022] Open
Abstract
Japanese encephalitis (JE), a viral disease has significantly increased worldwide especially, in the developing region due to challenges in immunization, vector control and lack of appropriate treatment methods. An effective, yet an expensive heat-killed vaccine is available for the disease. Therefore, the design and development of short peptide vaccine candidate is promising. We used immune-informatics methods to perform a comprehensive analysis of the entire JEV proteome of north Indian isolate to identify the conserved peptides binding known specific HLA alleles among the documented JEV genotypes 1, 2, 3, 4 and 5. The prediction analysis identified 102 class I (using propred I) and 118 class II (using propred) binding peptides at 4% threshold value. These predicted HLA allele binding peptides were further analyzed for potential conserved region using IEDB (an immune epitope database and analysis resource). This analysis shows that 78.81% of class II (in genotype 2) and 76.47% of HLA I (in genotype 3) bound peptides are conserved. The peptides IPIVSVASL, KGAQRLAAL, LAVFLICVL and FRTLFGGMS, VFLICVLTV, are top ranking with potential super antigenic property by binding to all HLA allele members of B7 and DR4 super-types, respectively. This data finds application in the design and development of short peptide vaccine candidates and diagnostic agents for JE following adequate validation and verification.
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Affiliation(s)
- Pawan Sharma
- School of Biotechnology, IFTM University, Lodhipur Rajput, Delhi Road (NH-24), Moradabad, 244001, U.P., India
- Institute of Biomedical Education and Research, Mangalayatan University, Aligarh, 202145, India
| | - Komal Saxena
- Institute of Biomedical Education and Research, Mangalayatan University, Aligarh, 202145, India
| | - Sanjay Mishra
- School of Biotechnology, IFTM University, Lodhipur Rajput, Delhi Road (NH-24), Moradabad, 244001, U.P., India
| | - Ajay Kumar
- Institute of Biomedical Education and Research, Mangalayatan University, Aligarh, 202145, India
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