title: Chitosan modification of adenovirus to modify transfection efficiency in bovine corneal epithelial cells.
abstract: BACKGROUND
  The purpose of this study is to modulate the transfection efficiency of adenovirus (Ad) on the cornea by the covalent attachment of chitosan on adenoviral capsids via a thioether linkage between chitosan modified with 2-iminothiolane and Ad cross-linked with N-[gamma-maleimidobutyryloxy]succinimide ester (GMBS).
  
  
  RESULTS
  Modified Ad was obtained by reaction with the heterobifunctional crosslinking reagent, GMBS, producing maleimide-modified Ad (Ad-GMBS). Then, the chitosan-SH was conjugated to Ad-GMBS via a thioether bond at different ratios of Ad to GMBS to chitosan-SH. The sizes and zeta potentials of unmodified Ad and chitosan-modified Ads were measured, and the morphologies of the virus particles were observed under transmission electron microscope. Primary cultures of bovine corneal epithelial cells were transfected with Ads and chitosan-modified Ads in the absence or presence of anti-adenovirus antibodies. Chitosan modification did not significantly change the particle size of Ad, but the surface charge of Ad increased significantly from -24.3 mV to nearly neutral. Furthermore, primary cultures of bovine corneal epithelial cells were transfected with Ad or chitosan-modified Ad in the absence or presence of anti-Ad antibodies. The transfection efficiency was attenuated gradually with increasing amounts of GMBS. However, incorporation of chitosan partly restored transfection activity and rendered the modified antibody resistant to antibody neutralization.
  
  
  CONCLUSIONS
  Chitosan can provide a platform for chemical modification of Ad, which offers potential for further in vivo applications.
authors: Department of Ophthalmology, National Taiwan University Hospital, College of Medicine, National Taiwan University, Taipei, Taiwan.
authors: I-Jong
authors: IJ
authors: Wang
authors: Min-Chao
authors: MC
authors: Jhuang
authors: Yu-Hsin
authors: YH
authors: Chen
authors: Lung-Kun
authors: LK
authors: Yeh
authors: Chia-Yang
authors: CY
authors: Liu
authors: Tai-Horng
authors: TH
authors: Young
mesh_terms: D000256:Adenoviridae / Q000235:genetics* / Q000276:immunology / Q000378:metabolism* / Q000502:physiology; D000818:Animals; D057134:Antibodies, Neutralizing / Q000276:immunology; D002213:Capsid / Q000378:metabolism; D002417:Cattle; D002462:Cell Membrane / Q000821:virology; D048271:Chitosan / Q000378:metabolism*; D004274:DNA, Recombinant / Q000235:genetics; D019573:Epithelium, Corneal / Q000166:cytology* / Q000378:metabolism*; D005822:Genetic Vectors / Q000235:genetics; D014162:Transfection / Q000379:methods*; D019076:Transgenes / Q000235:genetics; D053585:Virus Attachment
chemical_list: D057134:Antibodies, Neutralizing; D004274:DNA, Recombinant; D048271:Chitosan