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標題: Partially Neutralizing Potency against Emerging Genotype I Virus among Children Received Formalin- Inactivated Japanese Encephalitis Virus Vaccine
作者: Fan, Yi-Chin
Chen, Jo-Mei
Chiu, Hsien-Chung
Chen, Yi-Ying
Lin, Jen-Wei
Shih, Chen-Chang
Chen, Chih-Ming
Chang, Chao-Chin
Gwong-Jen, J.Chang
Chiou, Shyan-Song
摘要: Background: Genotype I (GI) Japanese encephalitis virus (JEV) that replaced GIII virus has become the dominant circulating virus in Asia. Currently, all registered live and inactivated JEV vaccines are derived from genotype III viruses. In Taiwan, the compulsory JEV vaccination policy recommends that children receives four doses of formalin-inactivated Nakayama (GIII) JEV vaccine. Methodology/Principal Findings: To evaluate the influence of genotype replacement on the post-vaccination viral neutralizing ability by GIII and GI viruses, the small panel of vaccinated-children serum specimens was assembled, and the reciprocal 50% plaque-reduction neutralizing antibody titers (PRNT50) were measured against Nakayama vaccine strain, CJN GIII human brain isolate and TC2009-1 GI mosquito isolate. The seropositivity rate (PRNT50$1:10) and geometric mean titers (GMT) against the TC2009-1 virus were the lowest among the three viruses. The protective threshold against the CJN and TC2009-1 viruses could only be achieved when the GMT against Nakayama virus was $1:20 or $1:80, respectively. Using undiluted vaccinees’ sera, the enhancement of JEV infection in K562 cells was observed in some low or non-neutralizing serum specimens. Conclusions/Significance: Our preliminary study has shown that neutralizing antibodies, elicited by the mouse brainderived and formalin-inactivated JEV Nakayama vaccine among a limited number of vaccinees, have reduced neutralizing capacity against circulating GI virus, but more detailed studies are needed to address the potential impact on the future vaccine policy.
Appears in Collections:微生物暨公共衛生學研究所



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