Project Details
Projekt
Overcoming innate immunity towards genetic therapies in the eye
Applicant
Professor M. Dominik Fischer, Ph.D.
Subject Area
Ophthalmology
Term
from 2018 to 2023
Project identifier
Deutsche Forschungsgemeinschaft (DFG) - Project number 399300408
A large number of blinding disorders caused by monogenic mutations lead to neuroretinal degeneration with no treatment currently available. Gene therapy carries the potential to counteract this degeneration and Adeno-associated virus (AAV) has become a widely used vector system for gene transfer in the eye. However, independent AAV gene therapy trials reported cases with ocular inflammation and loss of efficacy after initial functional improvements. One explanation for the decline of efficacy might be a host immune response directed against AAV and/or transduced cells. Our own data demonstrate that clinical grade AAV can indeed activate the pathogen-associated pattern recognition (PPR) system in the primate retina and consequently induce an immune response through effector cytokines. Although AAV biology has been studied quite extensively, the interaction between recombinant AAV and the PPR system in retinal cells is not well understood. As the PPR system and downstream effector cytokines help to stage a concerted immune response, a thorough understanding of these interactions is of critical importance for AAV-mediated gene therapy. This proposal aims to increase the safety and efficacy of future AAV-mediated gene transfer by identifying the key pathways leading to the ocular immune response against AAV and finding ways to modulate those to limit inflammation and ensure long-term therapeutic transgene expression. Specifically, we will use a unique collection of samples from current NHP and clinical trials to characterize the adaptive (humoral/cellular) immune response in NHP and human patients following ocular gene therapy with clinical grade AAV by ELISA, PBMC sub-population analysis (FACS), histology, immunohistochemistry and expression analysis. This will provide an overview of incidence and severity of ocular inflammation and immune response (aim1). Molecular and cell-biological techniques will be used to identify key PPR systems and associated pathways involved in sensing AAV or components and in triggering innate immune responses both in above samples and in appropriate in vitro models (aim2). Once key pathways are identified, strategies to prevent/block an immune response following AAV exposure are tested in a pilot study in vitro with the aim to enhance the safety and long term efficacy of AAV gene therapy (aim3).The proposed project will provide important knowledge about the interactions between AAV and the host retina and will deliver strategies on how to improve safety and efficacy of retinal gene therapy in its clinical application. The identification of strategies to suppress innate immune responses against AAV will likely also be of benefit to the wider scientific community in the pursuit of developing genetic therapies utilising viral vectors in general. Knowledge about the PPR system of the retina might also prove useful in the context of ocular cell transplants.
DFG Programme
Priority Programmes
