[Studies on the biological and genetic characteristics of a highly neurovirulent Japanese encephalitis virus strain SA4].
The biological and genetic characteristics of a highly neurovirulent JE virus strain SA4 were studied. Mice were inoculated intracerebrally with strain SA4 and SA14, and observed for 14 days, respectively. On different days, mice brains were harvested for titrations of the virus content in the brains. Full-length genome of SA4 was sequenced and compared with SA14 as well as other JE virus strains in the world. The results indicated that the mice inoculated by SA4 induced sickness and death more rapidly (24 hours faster) than those induced by the SA14. The virus titers in the brains of mice infected with SA4 were 0.5-1.0 lg PFU/mL higher than that infected with SA14. The sequence comparison indicated that the nucleotide and amino acid homology between SA4 and the other 21 JE strains were 84.6%-99.0% and 95.2%-99.7% respectively. Comparison with strain SA14 revealed that there were 17 amino acid differences between the two strains, of which 5 were in the E protein region. The results demonstrate that strain SA4 is a highly neurovirulent strain. The substitutions of the 17 amino acids in the SA4 strain can be the molecular basis for the biological characteristics of high neurovirulence.
Liu
Xin-Yu
XY
National Institute for the Control of Pharmaceutical and Biological Products, Beijing 100050, China.
Yu
Yong-Xin
YX
Yue
Guang-Zhi
GZ
Yang
Li-Hong
LH
Jia
Li-Li
LL
Dong
Guan-Mu
GM
D000818:Animals; D001921:Brain / Q000821:virology; D004664:Encephalitis Virus, Japanese / Q000145:classification / Q000235:genetics* / Q000302:isolation & purification / Q000472:pathogenicity*; D004672:Encephalitis, Japanese / Q000401:mortality / Q000821:virology*; D005838:Genotype; D006801:Humans; D051379:Mice; D017421:Sequence Analysis; D014759:Viral Envelope Proteins / Q000235:genetics; D014774:Virulence
D014759:Viral Envelope Proteins