scholarly journals Japanese encephalitis virus live attenuated vaccine strains display altered immunogenicity, virulence and genetic diversity

npj Vaccines ◽  
2021 ◽  
Vol 6 (1) ◽  
Author(s):  
Emily H. Davis ◽  
Andrew S. Beck ◽  
Li Li ◽  
Mellodee M. White ◽  
Marianne Banks Greenberg ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Japanese Encephalitis Virus ◽  
Japanese Encephalitis ◽  
Serial Passage ◽  
Encephalitis Virus ◽  
Wild Type ◽  
Live Attenuated Vaccine ◽  
Replication Complex ◽  
Generation Sequencing

AbstractJapanese encephalitis virus (JEV) is the etiological agent of Japanese encephalitis (JE). The most commonly used vaccine used to prevent JE is the live-attenuated strain SA14-14-2, which was generated by serial passage of the wild-type (WT) JEV strain SA14. Two other vaccine candidates, SA14-5-3 and SA14-2-8 were derived from SA14. Both were shown to be attenuated but lacked sufficient immunogenicity to be considered effective vaccines. To better contrast the SA14-14-2 vaccine with its less-immunogenic counterparts, genetic diversity, ribavirin sensitivity, mouse virulence and mouse immunogenicity of the three vaccines were investigated. Next generation sequencing demonstrated that SA14-14-2 was significantly more diverse than both SA14-5-3 and SA14-2-8, and was slightly less diverse than WT SA14. Notably, WT SA14 had unpredictable levels of diversity across its genome whereas SA14-14-2 is highly diverse, but genetic diversity is not random, rather the virus only tolerates variability at certain residues. Using Ribavirin sensitivity in vitro, it was found that SA14-14-2 has a lower fidelity replication complex compared to SA14-5-3 and SA14-2-8. Mouse virulence studies showed that SA14-2-8 was the most virulent of the three vaccine strains while SA14-14-2 had the most favorable combination of safety (virulence) and immunogenicity for all vaccines tested. SA14-14-2 contains genetic diversity and sensitivity to the antiviral Ribavirin similar to WT parent SA14, and this genetic diversity likely explains the (1) differences in genomic sequences reported for SA14-14-2 and (2) the encoding of major attenuation determinants by the viral E protein.

scholarly journals Nuclear Localization of Japanese Encephalitis Virus Core Protein Enhances Viral Replication

2005 ◽  
Vol 79 (6) ◽  
pp. 3448-3458 ◽  
Author(s):  
Yoshio Mori ◽  
Tamaki Okabayashi ◽  
Tetsuo Yamashita ◽  
Zijiang Zhao ◽  
Takaji Wakita ◽  
...  
Keyword(s):  
Japanese Encephalitis Virus ◽  
Cell Lines ◽  
Japanese Encephalitis ◽  
Nuclear Localization ◽  
Mammalian Cells ◽  
Core Protein ◽  
Encephalitis Virus ◽  
Wild Type ◽  
The Core

ABSTRACT Japanese encephalitis virus (JEV) core protein was detected in both the nucleoli and cytoplasm of mammalian and insect cell lines infected with JEV or transfected with the expression plasmid of the core protein. Mutation analysis revealed that Gly42 and Pro43 in the core protein are essential for the nuclear and nucleolar localization. A mutant M4243 virus in which both Gly42 and Pro43 were replaced by Ala was recovered by plasmid-based reverse genetics. In C6/36 mosquito cells, the M4243 virus exhibited RNA replication and protein synthesis comparable to wild-type JEV, whereas propagation in Vero cells was impaired. The mutant core protein was detected in the cytoplasm but not in the nucleus of either C6/36 or Vero cell lines infected with the M4243 virus. The impaired propagation of M4243 in mammalian cells was recovered by the expression of wild-type core protein in trans but not by that of the mutant core protein. Although M4243 mutant virus exhibited a high level of neurovirulence comparable to wild-type JEV in spite of the approximately 100-fold-lower viral propagation after intracerebral inoculation to 3-week-old mice of strain Jcl:ICR, no virus was recovered from the brain after intraperitoneal inoculation of the mutant. These results indicate that nuclear localization of JEV core protein plays crucial roles not only in the replication in mammalian cells in vitro but also in the pathogenesis of encephalitis induced by JEV in vivo.

scholarly journals Processing of Capsid Protein by Cathepsin L Plays a Crucial Role in Replication of Japanese Encephalitis Virus in Neural and Macrophage Cells

2007 ◽  
Vol 81 (16) ◽  
pp. 8477-8487 ◽  
Author(s):  
Yoshio Mori ◽  
Tetsuo Yamashita ◽  
Yoshinori Tanaka ◽  
Yoshimi Tsuda ◽  
Takayuki Abe ◽  
...  
Keyword(s):  
Japanese Encephalitis Virus ◽  
Capsid Protein ◽  
Japanese Encephalitis ◽  
Crucial Role ◽  
Cathepsin L ◽  
Encephalitis Virus ◽  
Amino Acid Residues ◽  
Wild Type ◽  
Macrophage Cells

ABSTRACT The flavivirus capsid protein not only is a component of nucleocapsids but also plays a role in viral replication. In this study, we found a small capsid protein in cells infected with Japanese encephalitis virus (JEV) but not in the viral particles. The small capsid protein was shown to be generated by processing with host cysteine protease cathepsin L. An in vitro cleavage assay revealed that cathepsin L cleaves the capsid protein between amino acid residues Lys18 and Arg19, which are well conserved among the mosquito-borne flaviviruses. A mutant JEV resistant to the cleavage of the capsid protein by cathepsin L was generated from an infectious cDNA clone of JEV by introducing a substitution in the cleavage site. The mutant JEV exhibited growth kinetics similar to those of the wild-type JEV in monkey (Vero), mosquito (C6/36), and porcine (PK15) cell lines, whereas replication of the mutant JEV in mouse macrophage (RAW264.7) and neuroblastoma (N18) cells was impaired. Furthermore, the neurovirulence and neuroinvasiveness of the mutant JEV to mice were lower than those of the wild-type JEV. These results suggest that the processing of the JEV capsid protein by cathepsin L plays a crucial role in the replication of JEV in neural and macrophage cells, which leads to the pathogenesis of JEV infection.

scholarly journals Potential Role of Birds in Japanese Encephalitis Virus Zoonotic Transmission and Genotype Shift

Viruses ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 357
Author(s):  
Muddassar Hameed ◽  
Abdul Wahaab ◽  
Mohsin Nawaz ◽  
Sawar Khan ◽  
Jawad Nazir ◽  
...  
Keyword(s):  
Japanese Encephalitis Virus ◽  
Japanese Encephalitis ◽  
Encephalitis Virus ◽  
Zoonotic Transmission ◽  
In Vivo Studies ◽  
Genotype I ◽  
Genotype Iii

Japanese encephalitis (JE) is a vaccine-preventable disease caused by the Japanese encephalitis virus (JEV), which is primarily prevalent in Asia. JEV is a Flavivirus, classified into a single serotype with five genetically distinct genotypes (I, II, III, IV, and V). JEV genotype III (GIII) had been the most dominant strain and caused numerous outbreaks in the JEV endemic countries until 1990. However, recent data shows the emergence of JEV genotype I (GI) as a dominant genotype and it is gradually displacing GIII. The exact mechanism of this genotype displacement is still unclear. The virus can replicate in mosquito vectors and vertebrate hosts to maintain its zoonotic life cycle; pigs and aquatic wading birds act as an amplifying/reservoir hosts, and the humans and equines are dead-end hosts. The important role of pigs as an amplifying host for the JEV is well known. However, the influence of other domestic animals, especially birds, that live in high abundance and close proximity to the human is not well studied. Here, we strive to briefly highlight the role of birds in the JEV zoonotic transmission, discovery of birds as a natural reservoirs and amplifying host for JEV, species of birds susceptible to the JEV infection, and the proposed effect of JEV on the poultry industry in the future, a perspective that has been neglected for a long time. We also discuss the recent in vitro and in vivo studies that show that the newly emerged GI viruses replicated more efficiently in bird-derived cells and ducklings/chicks than GIII, and an important role of birds in the JEV genotype shift from GIII to GI.

Protection of pigs against mosquito-borne japanese encephalitis virus by immunization with a live attenuated vaccine

1982 ◽  
Vol 2 (6) ◽  
pp. 355-360 ◽  
Author(s):  
Osamu Sasaki ◽  
Yoshiaki Karoji ◽  
Akio Kuroda ◽  
Toshiro Karaki ◽  
Kunihachi Takenokuma ◽  
...  
Keyword(s):  
Japanese Encephalitis Virus ◽  
Japanese Encephalitis ◽  
Encephalitis Virus ◽  
Live Attenuated Vaccine ◽  
Attenuated Vaccine

scholarly journals Targeting of the Nasal Mucosa by Japanese Encephalitis Virus for Non-Vector-Borne Transmission

2018 ◽  
Vol 92 (24) ◽  
Author(s):  
Obdulio García-Nicolás ◽  
Roman O. Braun ◽  
Panagiota Milona ◽  
Marta Lewandowska ◽  
Ronald Dijkman ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Japanese Encephalitis Virus ◽  
Japanese Encephalitis ◽  
Ex Vivo ◽  
Encephalitis Virus ◽  
Nasal Epithelium ◽  
Virus Shedding ◽  
Nasal Epithelial Cells ◽  
Vector Borne

ABSTRACTThe mosquito-borne Japanese encephalitis virus (JEV) causes severe central nervous system diseases and cycles betweenCulexmosquitoes and different vertebrates. For JEV and some other flaviviruses, oronasal transmission is described, but the mode of infection is unknown. Using nasal mucosal tissue explants and primary porcine nasal epithelial cells (NEC) at the air-liquid interface (ALI) and macrophages asex vivoandin vitromodels, we determined that the nasal epithelium could represent the route of entry and exit for JEV in pigs. Porcine NEC at the ALI exposed to with JEV resulted in apical and basolateral virus shedding and release of monocyte recruiting chemokines, indicating infection and replication in macrophages. Moreover, macrophages stimulated by alarmins, including interleukin-25, interleukin-33, and thymic stromal lymphopoietin, were more permissive to the JEV infection. Altogether, our data are important to understand the mechanism of non-vector-borne direct transmission of Japanese encephalitis virus in pigs.IMPORTANCEJEV, a main cause of severe viral encephalitis in humans, has a complex ecology composed of a mosquito-waterbird cycle and a cycle involving pigs, which amplifies virus transmission to mosquitoes, leading to increased human cases. JEV can be transmitted between pigs by contact in the absence of arthropod vectors. Moreover, virus or viral RNA is found in oronasal secretions and the nasal epithelium. Using nasal mucosa tissue explants and three-dimensional porcine nasal epithelial cells cultures and macrophages asex vivoandin vitromodels, we determined that the nasal epithelium could be a route of entry as well as exit for the virus. Infection of nasal epithelial cells resulted in apical and basolateral virus shedding and release of monocyte recruiting chemokines and therefore infection and replication in macrophages, which is favored by epithelial-cell-derived cytokines. The results are relevant to understand the mechanism of non-vector-borne direct transmission of JEV.

scholarly journals Amino Acid at Position 166 of NS2A in Japanese Encephalitis Virus (JEV) Is Associated with In Vitro Growth Characteristics of JEV

Viruses ◽  
2020 ◽  
Vol 12 (7) ◽  
pp. 709
Author(s):  
Shigeru Tajima ◽  
Satoshi Taniguchi ◽  
Eri Nakayama ◽  
Takahiro Maeki ◽  
Takuya Inagaki ◽  
...  
Keyword(s):  
Amino Acid ◽  
Japanese Encephalitis Virus ◽  
Japanese Encephalitis ◽  
Neuroblastoma Cells ◽  
Encephalitis Virus ◽  
Growth Potential ◽  
Sequencing Analysis ◽  
Murine Neuroblastoma ◽  
Growth Ability

We previously showed that the growth ability of the Japanese encephalitis virus (JEV) genotype V (GV) strain Muar is clearly lower than that of the genotype I (GI) JEV strain Mie/41/2002 in murine neuroblastoma cells. Here, we sought to identify the region in GV JEV that is involved in its low growth potential in cultured cells. An intertypic virus containing the NS1-3 region of Muar in the Mie/41/2002 backbone (NS1-3Muar) exhibited a markedly diminished growth ability in murine neuroblastoma cells. Moreover, the growth rate of a Muar NS2A-bearing intertypic virus (NS2AMuar) was also similar to that of Muar in these cells, indicating that NS2A of Muar is one of the regions responsible for the Muar-specific growth ability in murine neuroblastoma cells. Sequencing analysis of murine neuroblastoma Neuro-2a cell-adapted NS1-3Muar virus clones revealed that His-to-Tyr mutation at position 166 of NS2A (NS2A166) could rescue the low replication ability of NS1-3Muar in Neuro-2a cells. Notably, a virus harboring a Tyr-to-His substitution at NS2A166 (NS2AY166H) showed a decreased growth ability relative to that of the parental virus Mie/41/2002, whereas an NS2AMuar-based mutant virus, NS2AMuar-H166Y, showed a higher growth ability than NS2AMuar in Neuro-2a cells. Thus, these results indicate that the NS2A166 amino acid in JEV is critical for the growth and tissue tropism of JEV in vitro.

scholarly journals A Single Amino Acid Substitution in the NS2A Protein of Japanese Encephalitis Virus Affects Virus PropagationIn Vitrobut NotIn Vivo

2015 ◽  
Vol 89 (11) ◽  
pp. 6126-6130 ◽  
Author(s):  
Yuki Takamatsu ◽  
Kouichi Morita ◽  
Daisuke Hayasaka
Keyword(s):  
Amino Acid ◽  
Japanese Encephalitis Virus ◽  
Japanese Encephalitis ◽  
Encephalitis Virus ◽  
Single Amino Acid ◽  
Virus Propagation ◽  
Viral Loads ◽  
Unique Amino Acid

We identified a unique amino acid of NS2A113, phenylalanine, that affects the efficient propagation of two Japanese encephalitis virus strains, JaTH160 and JaOArS982, in neuroblastoma Neuro-2a cells but not in cell lines of extraneural origin. This amino acid did not affect viral loads in the brain or survival curves in mice. These findings suggest that virus propagationin vitromay not reflect the level of virus neuroinvasivenessin vivo.

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