title: Repeated delivery of adeno-associated virus vectors to the rabbit airway.
abstract: Efficient local expression from recombinant adeno-associated virus (rAAV)-cystic fibrosis (CF) transmembrane conductance regulator (CFTR) vectors has been observed in the airways of rabbits and monkeys for up to 6 months following a single bronchoscopic delivery. However, it is likely that repeated administrations of rAAV vectors will be necessary for sustained correction of the CF defect in the airways. The current study was designed to test the feasibility of repeated airway delivery of rAAV vectors in the rabbit lung. After two doses of rAAV-CFTR to the airways, rabbits generated high titers of serum anti-AAV neutralizing antibodies. Rabbits then received a third dose of a rAAV vector containing the green fluorescent protein (GFP) reporter gene packaged in either AAV serotype 2 (AAV2) or serotype 3 (AAV3) capsids. Each dose consisted of 1 ml containing 5 x 10(9) DNase-resistant particles of rAAV vector, having no detectable replication-competent AAV or adenovirus. Three weeks later, GFP expression was observed in airway epithelial cells despite high anti-AAV neutralizing titers at the time of delivery. There was no significant difference in the efficiency of DNA transfer or expression between the rAAV3 and rAAV2 groups. No significant inflammatory responses to either repeated airway exposure to rAAV2-CFTR vectors or to GFP expression were observed. These experiments demonstrate that serum anti-AAV neutralizing antibody titers do not predict airway neutralization in vivo and that repeated airway delivery rAAV allows for safe and effective gene transfer.
authors.affiliation: Eudowood Division of Pediatric Respiratory Sciences, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA. sbeck@jhmi.edu
authors.forename: S E
authors.initials: SE
authors.lastname: Beck
authors.forename: L A
authors.initials: LA
authors.lastname: Jones
authors.forename: K
authors.initials: K
authors.lastname: Chesnut
authors.forename: S M
authors.initials: SM
authors.lastname: Walsh
authors.forename: T C
authors.initials: TC
authors.lastname: Reynolds
authors.forename: B J
authors.initials: BJ
authors.lastname: Carter
authors.forename: F B
authors.initials: FB
authors.lastname: Askin
authors.forename: T R
authors.initials: TR
authors.lastname: Flotte
authors.forename: W B
authors.initials: WB
authors.lastname: Guggino
mesh_terms: D000818:Animals; D000914:Antibodies, Viral / Q000097:blood; D001980:Bronchi / Q000473:pathology / Q000821:virology*; D001992:Bronchoalveolar Lavage Fluid / Q000166:cytology / Q000276:immunology; D019005:Cystic Fibrosis Transmembrane Conductance Regulator / Q000235:genetics*; D004279:DNA, Viral / Q000032:analysis; D000229:Dependovirus / Q000235:genetics* / Q000276:immunology; D018014:Gene Transfer Techniques; D005822:Genetic Vectors / Q000008:administration & dosage*; D049452:Green Fluorescent Proteins; D008164:Luminescent Proteins / Q000235:genetics / Q000276:immunology; D008168:Lung / Q000473:pathology; D008297:Male; D009500:Neutralization Tests; D016133:Polymerase Chain Reaction; D011817:Rabbits; D011993:Recombinant Fusion Proteins; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: D000914:Antibodies, Viral; D004279:DNA, Viral; D008164:Luminescent Proteins; D011993:Recombinant Fusion Proteins; D019005:Cystic Fibrosis Transmembrane Conductance Regulator; D049452:Green Fluorescent Proteins