title: Selective uptake and sustained expression of AAV vectors following subcutaneous delivery.
abstract: BACKGROUND
  Recombinant adeno-associated viral (rAAV) vectors are capable of long-term expression of secreted and intracellular proteins following delivery to muscle, liver, and the central nervous system. In this study, we have evaluated subcutaneous injection of rAAV encoding a variety of transgenes as an alternative route of administration for the systemic delivery of therapeutic proteins.
  
  
  METHODS
  rAAV vectors encoding the human factor IX, human interferon-alpha 2a, murine erythropoietin (epo), and Escherichia coli lacZ genes were used for subcutaneous delivery into mature immunocompetent mice. Expression of factor IX and interferon in mouse serum was measured by ELISA. Expression of Epo was monitored by an increase in hemotocrit and by RIA. The tissue tropism of AAV transduction was determined by histochemistry following administration of the lacZ vector.
  
  
  RESULTS
  Long-term protein expression (at least one year) is demonstrated in the serum of immunocompetent mice following subcutaneous delivery of AAV vectors encoding the human factor IX and interferon genes. The murine epo gene delivered via this route resulted in levels of Epo that correlate with increased hematocrits of up to 90% for a duration of nine months. rAAV encoding the lacZ gene revealed that the panniculus carnosus, a skeletal muscle layer of the skin, was transduced upon subcutaneous administration.
  
  
  CONCLUSIONS
  This study shows that long-term expression of secreted proteins can be achieved using rAAV vectors injected subcutaneously as a single administration. The observation that the panniculus carnosus is the primary tissue transduced by rAAV illustrates the high tropism of rAAV for skeletal muscle.
authors.affiliation: Cell Genesys Inc., Foster City, CA 94404, USA.
authors.forename: B A
authors.initials: BA
authors.lastname: Donahue
authors.forename: J G
authors.initials: JG
authors.lastname: McArthur
authors.forename: S K
authors.initials: SK
authors.lastname: Spratt
authors.forename: D
authors.initials: D
authors.lastname: Bohl
authors.forename: C
authors.initials: C
authors.lastname: Lagarde
authors.forename: L
authors.initials: L
authors.lastname: Sanchez
authors.forename: B A
authors.initials: BA
authors.lastname: Kaspar
authors.forename: B A
authors.initials: BA
authors.lastname: Sloan
authors.forename: Y L
authors.initials: YL
authors.lastname: Lee
authors.forename: O
authors.initials: O
authors.lastname: Danos
authors.forename: R O
authors.initials: RO
authors.lastname: Snyder
mesh_terms: D000818:Animals; D000229:Dependovirus / Q000235:genetics*; D004921:Erythropoietin / Q000097:blood / Q000235:genetics; D005164:Factor IX / Q000096:biosynthesis / Q000235:genetics; D005260:Female; D015870:Gene Expression; D015316:Genetic Therapy; D005822:Genetic Vectors; D006801:Humans; D007279:Injections, Subcutaneous; D000077190:Interferon alpha-2; D016898:Interferon-alpha / Q000097:blood / Q000235:genetics; D007763:Lac Operon; D051379:Mice; D008807:Mice, Inbred BALB C; D018482:Muscle, Skeletal / Q000378:metabolism; D011994:Recombinant Proteins; D013997:Time Factors; D014018:Tissue Distribution; D014161:Transduction, Genetic
chemical_list: D000077190:Interferon alpha-2; D016898:Interferon-alpha; D011994:Recombinant Proteins; D004921:Erythropoietin; D005164:Factor IX