Phenotypic and Genotypic Comparison of a Live-Attenuated Genotype I Japanese Encephalitis Virus SD12-F120 Strain with Its Virulent Parental SD12 Strain

Viruses

MuhammadNaveed Anwar¹  Muddassar Hameed¹  Chenxi Li¹  Abdul Wahaab¹  Mona Sharma¹  Jianchao Wei¹  MuhammadIrfan Malik¹  Ke Liu¹  Yafeng Qiu¹  Xin Wang¹  Beibei Li¹  Zhiyong Ma¹  Linlin Pang¹ 

[1] Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai 200241, China;

关键词: Japanese encephalitis virus;    attenuation;    virulence;    vaccine;    genotype;    amino acid substitution;   

DOI  :  10.3390/v12050552

来源: DOAJ

【 摘 要 】

The phenotypic and genotypic characteristics of a live-attenuated genotype I (GI) strain (SD12-F120) of Japanese encephalitis virus (JEV) were compared with its virulent parental SD12 strain to gain an insight into the genetic changes acquired during the attenuation process. SD12-F120 formed smaller plaque on BHK-21 cells and showed reduced replication in mouse brains compared with SD12. Mice inoculated with SD12-F120 via either intraperitoneal or intracerebral route showed no clinical symptoms, indicating a highly attenuated phenotype in terms of both neuroinvasiveness and neurovirulence. SD12-F120 harbored 29 nucleotide variations compared with SD12, of which 20 were considered silent nucleotide mutations, while nine resulted in eight amino acid substitutions. Comparison of the amino acid variations of SD12-F120 vs SD12 pair with those from other four isogenic pairs of the attenuated and their virulent parental strains revealed that the variations at E¹³⁸ and E¹⁷⁶ positions of E protein were identified in four and three pairs, respectively, while the remaining amino acid variations were almost unique to their respective strain pairs. These observations suggest that the genetic changes acquired during the attenuation process were likely to be strain-specific and that the mechanisms associated with JEV attenuation/virulence are complicated.

【 授权许可】

Unknown