title: Generation and characterization of a cold-adapted attenuated live H3N2 subtype influenza virus vaccine candidate.
abstract: BACKGROUND
  H3N2 subtype influenza A viruses have been identified in humans worldwide, raising concerns about their pandemic potential and prompting the development of candidate vaccines to protect humans against this subtype of influenza A virus. The aim of this study was to establish a system for rescuing of a cold-adapted high-yielding H3N2 subtype human influenza virus by reverse genetics.
  
  
  METHODS
  In order to generate better and safer vaccine candidate viruses, a cold-adapted high yielding reassortant H3N2 influenza A virus was genetically constructed by reverse genetics and was designated as rgAA-H3N2. The rgAA-H3N2 virus contained HA and NA genes from an epidemic strain A/Wisconsin/67/2005 (H3N2) in a background of internal genes derived from the master donor viruses (MDV), cold-adapted (ca), temperature sensitive (ts), live attenuated influenza virus strain A/Ann Arbor/6/60 (MDV-A).
  
  
  RESULTS
  In this presentation, the virus HA titer of rgAA-H3N2 in the allantoic fluid from infected embryonated eggs was as high as 1:1024. A fluorescent focus assay (FFU) was performed 24-36 hours post-infection using a specific antibody and bright staining was used for determining the virus titer. The allantoic fluid containing the recovered influenza virus was analyzed in a hemagglutination inhibition (HI) test and the specific inhibition was found.
  
  
  CONCLUSIONS
  The results mentioned above demonstrated that cold-adapted, attenuated reassortant H3N2 subtype influenza A virus was successfully generated, which laid a good foundation for the further related research.
authors.affiliation: College of Animal Science and Veterinary Medicine, Jilin University, Changchun, Jilin, China.
authors.forename: Wen-qi
authors.initials: WQ
authors.lastname: An
authors.forename: Peng-hui
authors.initials: PH
authors.lastname: Yang
authors.forename: Yue-qiang
authors.initials: YQ
authors.lastname: Duan
authors.forename: De-yan
authors.initials: DY
authors.lastname: Luo
authors.forename: Chong
authors.initials: C
authors.lastname: Tang
authors.forename: Wei-hong
authors.initials: WH
authors.lastname: Jia
authors.forename: Li
authors.initials: L
authors.lastname: Xing
authors.forename: Xin-fu
authors.initials: XF
authors.lastname: Shi
authors.forename: Yu-jing
authors.initials: YJ
authors.lastname: Zhang
authors.forename: Xiu-fan
authors.initials: XF
authors.lastname: Liu
authors.forename: Xi-liang
authors.initials: XL
authors.lastname: Wang
mesh_terms: D000818:Animals; D019556:COS Cells; D002522:Chlorocebus aethiops; D004285:Dogs; D019267:Hemagglutinin Glycoproteins, Influenza Virus / Q000235:genetics; D053122:Influenza A Virus, H3N2 Subtype / Q000276:immunology*; D007252:Influenza Vaccines / Q000276:immunology*; D051379:Mice; D008807:Mice, Inbred BALB C; D009439:Neuraminidase / Q000235:genetics; D010957:Plasmids; D016865:Reassortant Viruses / Q000276:immunology; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014613:Vaccines, Attenuated / Q000276:immunology; D014764:Viral Proteins / Q000235:genetics
chemical_list: D019267:Hemagglutinin Glycoproteins, Influenza Virus; D007252:Influenza Vaccines; D014613:Vaccines, Attenuated; D014764:Viral Proteins; C487630:NA protein, influenza A virus; D009439:Neuraminidase