A recent study proved the concept that rAAV-mediated intramuscular delivery of scFv immunoadhesins to rhesus macaques can generate sustained high serum levels of these inhibitors, and protect study animals from a high-dose SIV challenge. However, some of the treated animals in that study developed anti-immunoadhesin antibody responses, resulting in clearance of antiviral inhibitors. Immune clearance of this sort has been well documented in the rAAV gene-therapy literature: expression of foreign proteins from rAAVs in large animal models can in general elicit strong trangene-directed immunity, leading to host clearance of the expressed transgene. Indeed immune clearence remains a key challenge to further translational development of rAAV-delivered therapies. It is therefore necessary to better define immune processes contributing to anti-inhibitor antibody responses, and to develop novel strategies to prevent clearance of expressed transgenes. These are the main objectives of Project 2. We proposed the following studies to accomplish these objectives: 1). To limit transduction and antigen presentation of rAAV-immunoadhesin in unintended target cells and tissues by evaluating a panel of muscle specific promoters for promoter strength, tissue specificity and feasibility for use in the packaging size-limited rAAV genome. 2). To detarget rAAV transduction from antigen presenting cells by harnessing endogenous miRNAs for dendritic cell specific post-transcriptional transgene silencing. 3). To induce sustained systemic tolerance to immunoadhesin expression by hepatotropic rAAV8-mediated and liver-specific transduction. These studies will generate an AAV vector genome optimized to limit clearence of expressed transgenes, an objective critical to the therapeutic use of AAV vectors in many contexts.

Public Health Relevance

rAAV-mediated delivery of anti-viral therapeutics is a promising approach to prevent and/or treat HIV infections. However, rAAV expression of anti-viral inhibitors in immune competent primates can occasionally elicit antibodies that interfere with the anti-viral activity of these inhibitors. This project will evaluate novel strategies for minimizing these anti-inhibitor antibody responses. In doing so, it will help improve the efficacy of AAV-delivered therapeutics useful for treating or preventing HIV-1 infection.

National Institute of Health (NIH)
National Institute of Allergy and Infectious Diseases (NIAID)
Research Program Projects (P01)
Project #
Application #
Study Section
Special Emphasis Panel (ZAI1-RB-A)
Project Start
Project End
Budget Start
Budget End
Support Year
Fiscal Year
Total Cost
Indirect Cost
Scripps Florida
United States
Zip Code
Wang, Dan; Li, Jia; Song, Chun-Qing et al. (2018) Cas9-mediated allelic exchange repairs compound heterozygous recessive mutations in mice. Nat Biotechnol 36:839-842
Fetzer, Ina; Gardner, Matthew R; Davis-Gardner, Meredith E et al. (2018) eCD4-Ig Variants That More Potently Neutralize HIV-1. J Virol 92:
Yoon, Yeonsoo; Wang, Dan; Tai, Phillip W L et al. (2018) Streamlined ex vivo and in vivo genome editing in mouse embryos using recombinant adeno-associated viruses. Nat Commun 9:412
Zhang, Wei; Li, Linjing; Su, Qin et al. (2018) Gene Therapy Using a miniCEP290 Fragment Delays Photoreceptor Degeneration in a Mouse Model of Leber Congenital Amaurosis. Hum Gene Ther 29:42-50
Tai, Phillip W L; Xie, Jun; Fong, Kaiyuen et al. (2018) Adeno-associated Virus Genome Population Sequencing Achieves Full Vector Genome Resolution and Reveals Human-Vector Chimeras. Mol Ther Methods Clin Dev 9:130-141
Mou, Huihui; Zhong, Guocai; Gardner, Matthew R et al. (2018) Conditional Regulation of Gene Expression by Ligand-Induced Occlusion of a MicroRNA Target Sequence. Mol Ther 26:1277-1286
Wang, Dan; Gao, Guangping (2018) Taking a Hint from Structural Biology: To Better Understand AAV Transport across the BBB. Mol Ther 26:336-338
Wang, Dan; Li, Jia; Tran, Karen et al. (2018) Slow Infusion of Recombinant Adeno-Associated Viruses into the Mouse Cerebrospinal Fluid Space. Hum Gene Ther Methods 29:75-85
Wang, Dan; Li, Shaoyong; Gessler, Dominic J et al. (2018) A Rationally Engineered Capsid Variant of AAV9 for Systemic CNS-Directed and Peripheral Tissue-Detargeted Gene Delivery in Neonates. Mol Ther Methods Clin Dev 9:234-246
Lu, Yi; Tai, Phillip W L; Ai, Jianzhong et al. (2018) Transcriptome Profiling of Neovascularized Corneas Reveals miR-204 as a Multi-target Biotherapy Deliverable by rAAVs. Mol Ther Nucleic Acids 10:349-360

Showing the most recent 10 out of 46 publications