Biological Characteristics of Attenuated Strain at222 of Japanese Encephalitis Virus

Objective To analyze and compare the biological characteristics of attenuated Japanese encephalitis virus strain at222 and its parental strain AT31 .Methods AT31 and at222 strains were propagat-ed in mosquito C6/36 cells, and the virus tilers and neurovirulences of them in supernatant were detected by plaque assay on Vero cells and intracerebral test in mice respectively. Results at222 strain grew slowly in mosquito cells,however, the titer(108PFU/ml)of it was almost identical to that of its parental strain AT31 .The plaques of at222 strain on Vero cells were significantly smaller than those of strain AT31 .The intracerebral test in mice also showed low neurovirulence of at222 strain. Conclusion The biological characteristics of at222 stain are cmopletely analyzed in this paper.The study provides a basis in theory for developing JE vaccine.