Gene transfer of immunomodulatory cytokines: Biological and functional characterization of adenoassociated virus expressing Interferon-alpha and Interleukin-15 in a HBV transgenic mouse model
- Autores: Marianna di Scala
- Directores de la Tesis: Gloria González Aseguinolaza (dir. tes.)
- Lectura: En la Universidad de Navarra ( España ) en 2013
- Idioma: español
- Tribunal Calificador de la Tesis: Jesus M. Prieto Valtueña (presid.), Juan José Lasarte Sagastibelza (secret.), Jessica Fioravanti (voc.), L. Anel (voc.), José Carlos Segovia Sanz (voc.)
- Materias:
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- Resumen
Worldwide 350 million people suffer from HBV infection and approximately 1 million people die annually because of HBV-induced liver pathologies. The host immune response to HBV antigens is a critical factor determining the outcome of the infection. In this thesis we have developed an immune-gene therapy strategy for the treatment of CHB. As gene vehicle, we employed recombinant AAV viruses and the expression of two immunostimulatory citokines, IFN-α and IL-15. In the first part, we tested the functionality of both virus in vivo and determine the optimal dosage. Next, we tested the antiviral activity of both vectors in a highly tolerant animal model of CHB, HBV transgenic mice.
We found that AAVIL-15 therapy increased serum levels of IL-15 bound to IL-15Rα leading to robust intrahepatic expansion of IFN-gamma-producing lymphocytes and increased HBV-specific CD8+ T-lymphocytes which, however, lacked cytolytic activity. Contrariwise, AAVIFN-α stimulated cytotoxic functions of HBV-specific CD8+T-cells without increasing their number. Notably, administration of AAVIL-15+AAVIFN-α to transgenic mice increased both the number and the cytolytic activity of anti-HBV CD8+T cells within the liver causing extensive hepatocellular necrosis and viral clearance. AAVIL-15-treated transgenic mice showed IFN-gamma-dependent hepatic PD-L1 upregulation and a high proportion of PD-1+ intrahepatic T-cells. Combining AAVIFN-α with AAVIL-15 reduced PD-1 and PD-L1 expression allowing HBV-specific T-lymphocytes to kill target cells. Accordingly, treatment of HBV transgenic mice with AAVIL-15 plus anti-PD-L1 antibody caused intense cytolysis and viral clearance. Our study defines a potent new approach to break immune tolerance with broad applications in chronic viral infections and neoplastic conditions.
Abbreviation: AAV: Adeno-associated virus; CHB: Chronic hepatitis B; IFN-α: Interferon-alpha; IL-15: Interleukin-15; HBV: Human hepatitis B virus; PD-1: Programmed-death 1; PD-L1: Programmed-death ligand 1.
