Journal
HUMAN GENE THERAPY
Volume 32, Issue 1-2, Pages 96-112Publisher
MARY ANN LIEBERT, INC
DOI: 10.1089/hum.2020.113
Keywords
immunosupression; rapamycin; AAV; non-human primate; DARPin
Categories
Funding
- amfAR (ARCHEGT) [109575-62-RGRL]
- National Institute of Allergy and Infectious Diseases [UM1 AI126623]
- University of Washington Center for AIDS Research (CFAR), an NIH [P30 AI 027757]
- NIMH
- NHLBI
- NIA
- NIGMS
- NIDDK
- NIH/NCI Cancer Center Support Grant [P30 CA015704]
- NIAID
- NCI
- NIDA
- NICHD
Ask authors/readers for more resources
The study on AAV6 and targeted AAV6 derivatives in rhesus macaques suggests that immunosuppression may enhance gene delivery efficiency, but safety concerns remain to be addressed.
Adeno-associated virus (AAV) vectors such as AAV6, which shows tropism for primary human CD4(+) T cells in vitro, are being explored for delivery of anti-HIV therapeutic modalities in vivo. However, pre-existing immunity and sequestration in nontarget organs can significantly hinder their performance. To overcome these challenges, we investigated whether immunosuppression would allow gene delivery by AAV6 or targeted AAV6 derivatives in seropositive rhesus macaques. Animals were immune suppressed with rapamycin before intravenous (IV) or subcutaneous (SC) delivery of AAV, and we monitored vector biodistribution, gene transfer, and safety. Macaques received phosphate-buffered saline, AAV6 alone, or an equal dose of AAV6 and an AAV6-55.2 vector retargeted to CD4 through a direct ankyrin repeat protein (DARPin). AAV6 and AAV6-55.2 vector genomes were found in peripheral blood mononuclear cells and most organs up to 28 days postadministration, with the highest levels seen in liver, spleen, lymph nodes (LNs), and muscle, suggesting that retargeting did not prevent vector sequestration. Despite vector genome detection, gene expression from AAV6-55.2 was not detected in any tissue. SC injection of AAV6 facilitated efficient gene expression in muscle adjacent to the injection site, plus low-level gene expression in spleen, LNs, and liver, whereas gene expression following IV injection of AAV6 was predominantly seen in the spleen. AAV vectors were well tolerated, although elevated liver enzymes were detected in three of four AAV-treated animals 14 days after rapamycin withdrawal. One SC-injected animal had muscle inflammation proximal to the injection site, plus detectable T cell responses against transgene and AAV6 capsid at study finish. Overall, our data suggest that rapamycin treatment may offer a possible strategy to express anti-HIV therapeutics such as broadly neutralizing antibodies from muscle. This study provides important safety and efficacy data that will aid study design for future anti-HIV gene therapies.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available