Arruda, VR, Schuettrumpf, J, Herzog, RW, Nichols, TC, Robinson, N, Lotfi, Y et al.. Safety and efficacy of factor IX gene transfer to skeletal muscle in murine and canine hemophilia B models by adeno-associated viral vector serotype 1. Blood 103: 85-92

Department of Pediatrics, University of Pennsylvani Medical Center, The Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA.
Blood (Impact Factor: 10.45). 02/2004; 103(1):85-92. DOI: 10.1182/blood-2003-05-1446
Source: PubMed


Adeno-associated viral (AAV) vectors (serotype 2) efficiently transduce skeletal muscle, and have been used as gene delivery vehicles for hemophilia B and for muscular dystrophies in experimental animals and humans. Recent reports suggest that AAV vectors based on serotypes 1, 5, and 7 transduce murine skeletal muscle much more efficiently than AAV-2, with reported increases in expression ranging from 2-fold to 1000-fold. We sought to determine whether this increased efficacy could be observed in species other than mice. In immunodeficient mice we saw 10- to 20-fold higher levels of human factor IX (hF.IX) expression at a range of doses, and in hemophilic dogs we observed approximately 50-fold higher levels of expression. The increase in transgene expression was due partly to higher gene copy number and a larger number of cells transduced at each injection site. In all immunocompetent animals injected with AAV-1, inhibitory antibodies to F.IX developed, but in immunocompetent mice treated with high doses of vector, inhibitory antibodies eventually disappeared. These studies emphasize that the increased efficacy of AAV-1 vectors carries a risk of inhibitor formation, and that further studies will be required to define doses and treatment regimens that result in tolerance rather than immunity to F.IX.

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    • "The choice of rAAV serotype is also of great importance; not only, it dictates capsid antigenicity but also modulates potential APC transduction and thus T cell responses toward encoded transgene products, such as the TetR-KRAB regulator. In this study, we used serotype 1, which has been demonstrated to result in high local vector concentrations after IM administration [42] and a higher likelihood of immunotoxicity [39]. The evaluation of other AAV serotypes could be interesting, such as serotype 8, which has already been demonstrated to be less immunogenic in the muscle [43], [44], [45]. "
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    ABSTRACT: Numerous studies have demonstrated the efficacy of the Adeno-Associated Virus (AAV)-based gene delivery platform in vivo. The control of transgene expression in many protocols is highly desirable for therapeutic applications and/or safety reasons. To date, the tetracycline and the rapamycin dependent regulatory systems have been the most widely evaluated. While the long-term regulation of the transgene has been obtained in rodent models, the translation of these studies to larger animals, especially to nonhuman primates (NHP), has often resulted in an immune response against the recombinant regulator protein involved in transgene expression regulation. These immune responses were dependent on the target tissue and vector delivery route. Here, using AAV vectors, we evaluated a doxycyclin-inducible system in rodents and macaques in which the TetR protein is fused to the human Krüppel associated box (KRAB) protein. We demonstrated long term gene regulation efficiency in rodents after subretinal and intramuscular administration of AAV5 and AAV1 vectors, respectively. However, as previously described for other chimeric transactivators, the TetR-KRAB-based system failed to achieve long term regulation in the macaque after intramuscular vector delivery because of the development of an immune response. Thus, immunity against the chimeric transactivator TetR-KRAB emerged as the primary limitation for the clinical translation of the system when targeting the skeletal muscle, as previously described for other regulatory proteins. New developments in the field of chimeric drug-sensitive transactivators with the potential to not trigger the host immune system are still needed.
    PLoS ONE 09/2014; 9(9):e102538. DOI:10.1371/journal.pone.0102538 · 3.23 Impact Factor
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    • "Thus, increased F.IX expression was achieved with delivery of AAV5-F.IX,10 and intravenous (IV) injection of AAV2-F.IX genomes cross-packaged into AAV-2/1, -2/4 and -2/6 vectors.11 AAV1-mediated F.IX delivery also improved correction of hF.IX levels in large animal models of hemophilia B.12 AAV7 and 8 were more efficient than AAV2 and AAV5-pseudotyped vectors for intramuscular (IM) gene delivery and viral promoters were more active than muscle-specific promoters13, 14 AAV8-F.IX vectors also showed superior hepatic transduction with intraportal delivery in mice and non-human primates.15, 16 "
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    ABSTRACT: Neonatal AAV8-mediated Factor IX (F.IX) gene delivery was applied as a model for exploring mechanisms of tolerance induction during immune ontogeny. Intraperitoneal delivery of AAV8/ Factor IX (hF.IX) during weeks 1-4 of life, over a 20-fold dose range, directed stable hF.IX expression, correction of coagulopathy in F.IX-null hemophilia B mice, and induction of tolerance to hF.IX; however, only primary injection at 1-2 days of life enabled increasing AAV8-mediated hF.IX expression after re-administration, due to the absence of anti-viral capsid antibodies. Adoptive splenocyte transfer from tolerized mice demonstrated induction of CD4(+)CD25(+) T regulatory (Treg) populations that specifically suppressed anti-hF.IX antibody responses, but not responses to third party antigen. Induction of hF.IX antibodies was only observed in tolerized mice after in vivo CD4(+)CD25(+) cell depletion and hF.IX challenge. Thus, primary injection of AAV during a critical period in the first week of life does not elicit antiviral responses, enabling re-administration of AAV and augmentation of hF.IX levels. Expansion of hF.IX-specific CD4(+)CD25(+) Tregs has a major role in tolerance induction early in immune ontogeny. Neonatal gene transfer provides a useful approach for defining the ontogeny of immune responses and may suggest approaches for inducing tolerance in the context of genetic therapies.Gene Therapy advance online publication, 13 June 2013; doi:10.1038/gt.2013.22.
    Gene therapy 06/2013; 20(10). DOI:10.1038/gt.2013.22 · 3.10 Impact Factor
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    • "In the present study, we evaluated the feasibility to effect long-term therapeutic correction of PKU by intramuscular injection-mediated liver transduction with various alternative rAAV serotypes as a preliminary assessment toward multiple combined approaches. The choice of AAV serotypes and the intramuscular administration route were selected for these experiments because (1) liver as well as skeletal muscle have been successfully transduced with rAAV pseudotype 8 in various animal models (Sarkar et al., 2004; Wang et al., 2005; Inagaki et al., 2006), and (2) rAAV2=8-mediated liver transduction is now being considered for treatment of patients with hemophilia B (Arruda et al., 2004). Similarly, rAAV pseudotype 1 is reportedly the most efficient vector for muscle transduction in mice (Hauck and Xiao, 2003; Louboutin et al., 2005). "
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