title: Improvement of retroviral vectors by coating with poly(ethylene glycol)-poly(L-lysine) block copolymer (PEG-PLL).
abstract: BACKGROUND
  Although some cationic reagents, such as polybrene, improve gene transduction in vitro, their use in vivo is prohibited due to their toxicity to the exposed cells. This paper demonstrates that a new cationic reagent, poly(ethylene glycol)-poly(L-lysine) block copolymer (PEG-PLL), improves gene transduction with retroviral vectors without increasing cell toxicity.
  
  
  METHODS
  A retroviral vector derived from the Moloney leukemia virus, containing the lacZ gene, was modified with PEG-PLL prior to transduction into NIH3T3, Lewis lung carcinoma, and primary cultured mouse brain cells. LacZ transduction efficacy was evaluated by counting the number of X-Gal-positive cells.
  
  
  RESULTS
  We have demonstrated that PEG-PLL is able to stably modify the viral particle surface due to the affinity of the PEG moiety to the biomembrane, and neutralizes negative charges by the cationic nature of the poly-lysine residue. Thus, PEG-PLL increased the gene transduction efficiency and minimized cell toxicity because free PEG-PLL was removable by centrifugation. We have shown that PEG-PLL increased the viral gene transduction efficiency 3- to 7-fold with NIH3T3 or Lewis lung carcinoma cell lines without increasing cytotoxicity. It improved retroviral gene transduction efficacy even against labile cells, such as primary cultured brain cells.
  
  
  CONCLUSIONS
  PEG-PLL is a novel reagent that improves retroviral gene transduction efficacy without increasing cytotoxicity.
authors.affiliation: National Institute for Physiological Sciences, Okazaki National Research Institutes, Okazaki, Japan.
authors.forename: Hiromichi
authors.initials: H
authors.lastname: Katakura
authors.forename: Atsushi
authors.initials: A
authors.lastname: Harada
authors.forename: Kazunori
authors.initials: K
authors.lastname: Kataoka
authors.forename: Miki
authors.initials: M
authors.lastname: Furusho
authors.forename: Fumihiro
authors.initials: F
authors.lastname: Tanaka
authors.forename: Hiromi
authors.initials: H
authors.lastname: Wada
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Ikenaka
mesh_terms: D016475:3T3 Cells; D000818:Animals; D018827:Carcinoma, Lewis Lung / Q000235:genetics; D002478:Cells, Cultured; D002498:Centrifugation; D005822:Genetic Vectors / Q000737:chemistry*; D008239:Lysine / Q000031:analogs & derivatives* / Q000737:chemistry*; D051379:Mice; D011092:Polyethylene Glycols / Q000737:chemistry*; D012190:Retroviridae / Q000235:genetics*; D013499:Surface Properties; D014161:Transduction, Genetic / Q000379:methods*; D014407:Tumor Cells, Cultured
chemical_list: C092361:poly(ethylene glycol) lysine copolymer; D011092:Polyethylene Glycols; D008239:Lysine