title: [Expression of tick-borne encephalitis virus prM-E protein in insect cells and studies on its antigenicity].
abstract: BACKGROUND
  To express the prM-E protein in Sf9 cells, and lay a basis for further study on the function of the viral proteins and development of specific diagnostic reagents.
  
  
  METHODS
  The recombinant prM-E protein of tick-borne encephalitis virus was expressed in insect cell Sf9 by RT-PCR amplification of prM-E gene, construction of donor plasmid of Bac-to-Bac baculovirus expression system, homologous recombination of donor plasmid with bacmid DNA at the site of Tn7 and transfection of insect cell Sf9.
  
  
  RESULTS
  Recombinant subviral particles, about 30 nm in diameter, consisting of prM-E were observed by electron microscope in the supernatant of infected cells, which indicated that infected cells released virus-like particles (VLPs) into the culture medium. The results of Western-blot and the indirect immunofluorescence assay (IFA) showed that the recombinant proteins retained antigenic and conformational structures similar to those of native virus proteins. Using the recombinant prM-E as antigens to detect samples of patient sera by ELISA and IFA, all of 16 sera from patients with tick-borne encephalitis were positive and all of 6 sera from other patients were negative.
  
  
  CONCLUSIONS
  The prM-E protein expressed in insect cells retains good antigenicity.
authors.affiliation: Institute of Microbiology and Epidemiology, Academy of Military Medical Sciences, State Key Laboratory of Pathogen and Biosecurity, Beijing 100071, China.
authors.forename: Yan-li
authors.initials: YL
authors.lastname: Liu
authors.forename: Bing-yin
authors.initials: BY
authors.lastname: Si
authors.forename: Yi
authors.initials: Y
authors.lastname: Hu
authors.forename: Yu
authors.initials: Y
authors.lastname: Zhang
authors.forename: Yin-hui
authors.initials: YH
authors.lastname: Yang
authors.forename: Qing-yu
authors.initials: QY
authors.lastname: Zhu
mesh_terms: D000818:Animals; D015153:Blotting, Western; D002460:Cell Line; D004669:Encephalitis Viruses, Tick-Borne / Q000235:genetics*; D019084:Fluorescent Antibody Technique, Indirect; D015967:Gene Expression Regulation, Viral; D020133:Reverse Transcriptase Polymerase Chain Reaction; D018411:Spodoptera; D014759:Viral Envelope Proteins / Q000235:genetics* / Q000276:immunology / Q000378:metabolism
chemical_list: D014759:Viral Envelope Proteins; C074932:prM protein, Flavivirus