title: [Effect of Deletion of the Carboxyl Terminal of the NS1 Protein on Pathogenicity of the Influenza B Virus].
abstract: To analyze the molecular basis of the variation of the pathogenicity of the influenza B virus, we rescued a recombinant virus with a deletion in the carboxyl terminal of the NS1 protein using reverse genetics based on the parental virus B-S9 of B/Yamagata/16/88. A mutant strain with a deletion of 171 amino acids in the carboxyl terminal of the NS1 protein was named "B-L5". BALB/c mice were inoculated with 3 X 105 EID50 of B-L5 and the parental virus B-S9, respectively. Then, weight changes, survival, and viral titers were documented. During 3 days post-inoculation (dpi) to 7 dpi, the weight of mice infected with B-S9 decreased. However, the weight of mice infected with B-L5 showed weight decreases only at 2 dpi, and quickly recovered at 3 dpi. B-S9 and B-L5 could replicate in the lungs of BALB/c mice. However, viral titers in the lungs of mice infected with B-L5 were 7900-times lower than those of mice infected with B-S9 at 3 dpi. Viral titers in the lungs of mice infected with B-L5 were not detected at 6 dpi. These results showed that, compared with the parent virus B-S9, the mutant virus B-L5 showed lower pathogenicity in BALB/c mice. Our study suggests that deletion of the carboxyl terminal of the NS1 protein decreases the pathogenicity of the influenza B virus. Establishment of a reverse-genetics system for the B influenza virus will provide a platform for studying its pathogenesis, and mechanism of transmission, and for developing live-attenuated influenza B virus vaccines.
authors.forename: Xue
authors.initials: X
authors.lastname: Li
authors.forename: Zhijun
authors.initials: Z
authors.lastname: Yu
authors.forename: Weiyang
authors.initials: W
authors.lastname: Sun
authors.forename: Qiang
authors.initials: Q
authors.lastname: Chen
authors.forename: Tiecheng
authors.initials: T
authors.lastname: Wang
authors.forename: Songtao
authors.initials: S
authors.lastname: Yang
authors.forename: Geng
authors.initials: G
authors.lastname: Huang
authors.forename: Yuwei
authors.initials: Y
authors.lastname: Gao
authors.forename: Xianzhu
authors.initials: X
authors.lastname: Xia
authors.forename: Xuemei
authors.initials: X
authors.lastname: Zhang
mesh_terms: D000818:Animals; D001835:Body Weight; D004285:Dogs; D005260:Female; D057809:HEK293 Cells; D006801:Humans; D009981:Influenza B virus / Q000235:genetics* / Q000472:pathogenicity* / Q000502:physiology; D061985:Madin Darby Canine Kidney Cells; D051379:Mice; D008807:Mice, Inbred BALB C; D017384:Sequence Deletion; D016019:Survival Analysis; D019562:Viral Load / Q000235:genetics; D017361:Viral Nonstructural Proteins / Q000737:chemistry* / Q000235:genetics*; D014774:Virulence
chemical_list: C085820:INS1 protein, influenza virus; D017361:Viral Nonstructural Proteins