Molecular Therapy: Methods & Clinical Development (Mar 2021)

AAV8 locoregional delivery induces long-term expression of an immunogenic transgene in macaques despite persisting local inflammation

  • Gwladys Gernoux,
  • Mickaël Guilbaud,
  • Marie Devaux,
  • Malo Journou,
  • Virginie Pichard,
  • Nicolas Jaulin,
  • Adrien Léger,
  • Johanne Le Duff,
  • Jack-Yves Deschamps,
  • Caroline Le Guiner,
  • Philippe Moullier,
  • Yan Cherel,
  • Oumeya Adjali

Journal volume & issue
Vol. 20
pp. 660 – 674

Abstract

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Adeno-associated virus (AAV) vectors are considered efficient vectors for gene transfer, as illustrated by recent successful clinical trials targeting retinal or neurodegenerative disorders. However, limitations as host immune responses to AAV capsid or transduction of limited regions must still be overcome. Here, we focused on locoregional (LR) intravenous perfusion vector delivery that allows transduction of large muscular areas and is considered to be less immunogenic than intramuscular (IM) injection. To confirm this hypothesis, we injected 6 cynomolgus monkeys with an AAV serotype 8 (AAV8) vector encoding for the highly immunogenic GFP driven by either a muscle-specific promoter (n = 3) or a cytomegalovirus (CMV) promoter (n = 3). We report that LR delivery allows long-term GFP expression in the perfused limb (up to 1 year) despite the initiation of a peripheral transgene-specific immune response. The analysis of the immune status of the perfused limb shows that LR delivery induces persisting inflammation. However, this inflammation is not sufficient to result in transgene clearance and is balanced by resident regulatory T cells. Overall, our results suggest that LR delivery promotes persisting transgene expression by induction of Treg cells in situ and might be a safe alternative to IM route to target large muscle territories for the expression of secreted therapeutic factors.

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