Infectivity of full-length cDNA clone of attenuated Japanese encephalitis virus strain SA14-14-2.

Objective To establish an infectious transcript on the basis of full-length cDNA clone of Japanese encephalitis virus(JEV),obtain the recovery virus and provide a method for study on pathogenic mechanism and molecular virology of JEV as well as development of JEV vaccine.Methods The full-length cDNA of JEV was cloned into modified vector pBluescript KS Ⅱ(+),followed by in vitro transcription using T7 promoter and Lipofectamine-mediated transfection to BHK-21 cells.The recovery virus was identified by RT-PCR,sequencing,indirect IFA and plaque formation test.Results Obvious CPE was observed in the BHK-21 cells transfected with transcript.The harvested recovery virus was identified as JEV.Conclusion A method for obtaining infectious JEV RNA by in vitro transcription of full-length cDNA clone was developed,which laid a foundation of study on molecular biology of JEV and vaccine development.