title: Reduced retinal transduction and enhanced transgene-directed immunogenicity with intravitreal delivery of rAAV following posterior vitrectomy in dogs.
abstract: Adeno-associated virus (AAV) vector-based gene therapy is a promising treatment strategy for delivery of neurotrophic transgenes to retinal ganglion cells (RGCs) in glaucoma patients. Retinal distribution of transgene expression following intravitreal injection (IVT) of AAV is variable in animal models and the vitreous humor may represent a barrier to initial vector penetration. The primary goal of our study was to investigate the effect of prior core vitrectomy with posterior hyaloid membrane peeling on pattern and efficiency of transduction of a capsid amino acid substituted AAV2 vector, carrying the green fluorescent protein (GFP) reporter transgene following IVT in dogs. When progressive intraocular inflammation developed starting 4 weeks post IVT, the study plan was modified to allow detailed characterization of the etiology as a secondary goal. Unexpectedly, surgical vitrectomy was found to significantly limit transduction, whereas in non-vitrectomized eyes transduction efficiency reached upwards to 37.3% of RGC layer cells. The developing retinitis was characterized by mononuclear cell infiltrates resulting from a delayed-type hypersensitivity reaction, which we suspect was directed at the GFP transgene. Our results, in a canine large animal model, support caution when considering surgical vitrectomy before IVT for retinal gene therapy in patients, as prior vitrectomy appears to significantly reduce transduction efficiency and may predispose the patient to development of vector-induced immune reactions.
authors.affiliation: Department of Small Animal Clinical Sciences, Michigan State University, East Lansing, MI, USA.
authors.forename: R F
authors.initials: RF
authors.lastname: Boyd
authors.affiliation: Department of Ophthalmology, University of Florida College of Medicine, Gainesville, FL, USA.
authors.forename: S L
authors.initials: SL
authors.lastname: Boye
authors.affiliation: Department of Pediatrics, University of Florida College of Medicine, Gainesville, FL, USA.
authors.forename: T J
authors.initials: TJ
authors.lastname: Conlon
authors.affiliation: Department of Pediatrics, University of Florida College of Medicine, Gainesville, FL, USA.
authors.forename: K E
authors.initials: KE
authors.lastname: Erger
authors.affiliation: Diagnostic Center for Population and Animal Health, Michigan State University, East Lansing, MI, USA.
authors.forename: D G
authors.initials: DG
authors.lastname: Sledge
authors.affiliation: Diagnostic Center for Population and Animal Health, Michigan State University, East Lansing, MI, USA.
authors.forename: I M
authors.initials: IM
authors.lastname: Langohr
authors.affiliation: Department of Ophthalmology, University of Florida College of Medicine, Gainesville, FL, USA.
authors.forename: W W
authors.initials: WW
authors.lastname: Hauswirth
authors.affiliation: Department of Small Animal Clinical Sciences, Michigan State University, East Lansing, MI, USA.
authors.forename: A M
authors.initials: AM
authors.lastname: Komáromy
authors.affiliation: Department of Ophthalmology, University of Florida College of Medicine, Gainesville, FL, USA.
authors.forename: S E
authors.initials: SE
authors.lastname: Boye
authors.affiliation: Department of Small Animal Clinical Sciences, Michigan State University, East Lansing, MI, USA.
authors.forename: S M
authors.initials: SM
authors.lastname: Petersen-Jones
authors.affiliation: Department of Small Animal Clinical Sciences, Michigan State University, East Lansing, MI, USA.
authors.forename: J T
authors.initials: JT
authors.lastname: Bartoe
mesh_terms: D000818:Animals; D000229:Dependovirus / Q000235:genetics*; D004285:Dogs; D005822:Genetic Vectors; D049452:Green Fluorescent Proteins / Q000235:genetics; D006801:Humans; D012160:Retina / Q000378:metabolism; D014161:Transduction, Genetic; D019076:Transgenes; D014821:Vitrectomy
chemical_list: D049452:Green Fluorescent Proteins