title: Targeted inhibition of HBV gene expression by single-chain antibody mediated small interfering RNA delivery.
abstract: RNA interference is highly effective at inhibiting HBV gene expression and replication. However, before small interfering RNA (siRNA) can be used in the clinic, it is essential to develop a system to target their delivery. Antibody-mediated delivery is a novel approach for targeting siRNA to appropriate cells. In this report, we asked whether this siRNA delivery strategy would be effective against HBV. Of 5 candidates, a specific siRNA that effectively inhibited HBV gene expression and replication was determined. Two fusion proteins, s-tP and sCkappa-tP, were constructed to contain a single chain of the human variable fragment, scFv, against hepatitis B surface antigen (HBsAg), a truncated protamine (tP), and in the case of sCkappa-tP, a constant region of the kappa chain (Ckappa). S-tP and sCkappa-tP were developed to provide targeted delivery of the siRNA, siRNA expressing cassettes (SEC), and siRNA-producing plasmids. Fluorescein isothiocyanate-siRNA, fluorescein isothiocyanate-SEC, and plasmid DNA were specifically delivered into HBsAg-positive cells using the sCkappa-tP fusion protein, and effectively inhibited HBV gene expression and replication. HBV gene expression was also inhibited by siRNA or siRNA-producing plasmids in HBV transgenic mice.
  
  
  CONCLUSIONS
  Our results describe a potential method for the targeted delivery of siRNA or siRNA-producing plasmids against HBV, using anti-HBsAg fusion proteins.
authors.affiliation: State Key Laboratory of Cancer Biology, Department of Immunology, Xijing Hospital, Fourth Military Medical University, Xi'an, China.
authors.forename: Wei-Hong
authors.initials: WH
authors.lastname: Wen
authors.forename: Jia-Yun
authors.initials: JY
authors.lastname: Liu
authors.forename: Wei-Jun
authors.initials: WJ
authors.lastname: Qin
authors.forename: Jing
authors.initials: J
authors.lastname: Zhao
authors.forename: Tao
authors.initials: T
authors.lastname: Wang
authors.forename: Lin-Tao
authors.initials: LT
authors.lastname: Jia
authors.forename: Yan-Ling
authors.initials: YL
authors.lastname: Meng
authors.forename: Hui
authors.initials: H
authors.lastname: Gao
authors.forename: Cai-Fang
authors.initials: CF
authors.lastname: Xue
authors.forename: Bo-Quan
authors.initials: BQ
authors.lastname: Jin
authors.forename: Li-Bo
authors.initials: LB
authors.lastname: Yao
authors.forename: Si-Yi
authors.initials: SY
authors.lastname: Chen
authors.forename: An-Gang
authors.initials: AG
authors.lastname: Yang
mesh_terms: D000818:Animals; D006528:Carcinoma, Hepatocellular; D045744:Cell Line, Tumor; D015967:Gene Expression Regulation, Viral / Q000276:immunology; D006511:Hepatitis B Antigens / Q000494:pharmacology*; D006515:Hepatitis B virus / Q000235:genetics* / Q000276:immunology; D006801:Humans; D008113:Liver Neoplasms; D008297:Male; D051379:Mice; D008822:Mice, Transgenic; D010957:Plasmids; D016133:Polymerase Chain Reaction; D034622:RNA Interference; D034741:RNA, Small Interfering / Q000235:genetics* / Q000276:immunology*
chemical_list: D006511:Hepatitis B Antigens; D034741:RNA, Small Interfering