Adeno-associated viral (AAV) gene transfer represents a promising treatment for hemophilia, showing first success in Phase I/II clinical trials with long-term systemic coagulation FIX expression in patients with hemophilia B. However, CD8+ T cell responses to input viral capsid antigen have emerged as a substantial hurdle. In addition, treatment of hemophilia generally bears a risk for inhibitory antibody (inhibitor) formation against the therapeutic clotting factor. While our pre-clinical data have shown the ability of hepatic AAV gene transfer to induce immune tolerance to FIX, moving forward toward the more immunogenic FVIII in gene therapy for hemophilia A remains a challenge. The complex problems of immune rejection of vector or transgene product require a multi-pronged approach of synergistic strategies aimed at reducing immunogenicity of the vector and at activation of immune regulatory pathways that serve as a ?backup mechanism? to suppress adaptive immune responses that may still occur, ultimately accomplishing long-term immune tolerance and thereby assuring sustained therapy. The focus of this proposal is the development of strategies and protocols for suppression of unwanted immune responses by regulatory T cells (Treg), and to create conditions that enhance immune regulation, including induction, expansion, and migration of Treg. Previously, we established that induction of CD4+CD25+FoxP3+ Treg by hepatocyte-derived transgene expression is crucial for tolerance to the transgene product upon liver-directed gene transfer. Here, we will continue to exploit the mechanisms that define the interplay between Treg and dendritic cells to induce and expand FoxP3+ Treg and alternative Treg (CD4+CD25-LAP+ and Tr1 cells). By improving induction and expansion of Treg, and their ability to migrate, we empower these cells to optimally control unwanted immune responses to vector and transgene product. Proposed experiments are grouped in the following specific aims:
Aim 1 : Dissect the mechanisms by which expansion and migration to the liver of FoxP3+ Treg, Tr1, or LAP+ Treg cells can be triggered by ligands of the receptors GITR, CX3CR1 and VEGFR.
Aim 2 : Test the hypothesis that empowering by plasmacytoid and CX3CR1+ dendritic cells promotes expansion and migration of Treg cells in the liver in hepatic AAV gene transfer for hemophilia.
Aim 3 : Develop immune tolerance protocols based on the alternative and synergistic use of distinct subsets of Treg cells: FoxP3+ Treg, Tr1 and/or LAP+ Treg cells.
Aim 4 : Develop an in vivo system that enables studies of immune responses and regulation to liver gene transfer with human hepatocytes and immune cells.

Public Health Relevance

Hemophilia afflicts in 5000 male births worldwide and is associated with significant morbidity as well as high costs in current treatment. Gene therapy has provided clinical benefit in treatment of hemophilia but is hampered by patients' immune responses. The goal of this proposal is overcome these immunological hurdles so that gene therapy could become curative of the disease in many patients.

National Institute of Health (NIH)
National Heart, Lung, and Blood Institute (NHLBI)
Research Project (R01)
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Gene and Drug Delivery Systems Study Section (GDD)
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Sarkar, Rita
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University of Florida
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Biswas, Moanaro; Kumar, Sandeep R P; Terhorst, Cox et al. (2018) Gene Therapy With Regulatory T Cells: A Beneficial Alliance. Front Immunol 9:554
Mendoza, Juan L; Schneider, William M; Hoffmann, Hans-Heinrich et al. (2017) The IFN-?-IFN-?R1-IL-10R? Complex Reveals Structural Features Underlying Type III IFN Functional Plasticity. Immunity 46:379-392
Herzog, Roland W; Cooper, Mario; Perrin, George Q et al. (2017) Regulatory T cells and TLR9 activation shape antibody formation to a secreted transgene product in AAV muscle gene transfer. Cell Immunol :
Herzog, Roland W; Nichols, Timothy C; Su, Jin et al. (2017) Oral Tolerance Induction in Hemophilia B Dogs Fed with Transplastomic Lettuce. Mol Ther 25:512-522
Biswas, Moanaro; Rogers, Geoffrey L; Sherman, Alexandra et al. (2017) Combination therapy for inhibitor reversal in haemophilia A using monoclonal anti-CD20 and rapamycin. Thromb Haemost 117:33-43
Rogers, Geoffrey L; Shirley, Jamie L; Zolotukhin, Irene et al. (2017) Plasmacytoid and conventional dendritic cells cooperate in crosspriming AAV capsid-specific CD8+ T cells. Blood 129:3184-3195
Wang, Xiaomei; Herzog, Roland W; Byrne, Barry J et al. (2017) Immune Modulatory Cell Therapy for Hemophilia B Based on CD20-Targeted Lentiviral Gene Transfer to Primary B Cells. Mol Ther Methods Clin Dev 5:76-82
Kumar, Sandeep R P; Hoffman, Brad E; Terhorst, Cox et al. (2017) The Balance between CD8+ T Cell-Mediated Clearance of AAV-Encoded Antigen in the Liver and Tolerance Is Dependent on the Vector Dose. Mol Ther 25:880-891
Herzog, Roland W (2017) Complexity of immune responses to AAV transgene products - Example of factor IX. Cell Immunol :
Palaschak, Brett; Marsic, Damien; Herzog, Roland W et al. (2017) An Immune-Competent Murine Model to Study Elimination of AAV-Transduced Hepatocytes by Capsid-Specific CD8+ T Cells. Mol Ther Methods Clin Dev 5:142-152

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