Cellular Immune Responses Induced by Subretinal AAV Gene Transfer can be Restrained by the Subretinal Associated Immune Inhibition Mechanism

For more than a decade, AAV-mediated gene transfer has been tested successfully in clinical trials to treat inherited retinal diseases. Despite the eye’s immune-privileged status and the use of corticoids as an adjunct treatment, some patients display inflammatory events which led us to question the immune consequences of a subretinal AAV administration. We first characterized anti-transgene immune responses induced in the periphery by injecting increasing doses of AAV8 encoding reporter proteins fused with the HY male antigen into the subretinal space of female C57BL/6 and rd10 mice. Transgene expression was monitored over time with bioluminescence imaging and T-cell immune responses in the spleen were analyzed by IFNγ ELISpot and cytokine multiplex assays. Our data show that an AAV8 injection causes proinflammatory T-cell immune response against the transgene product, correlated with the transgene expression level at 2.109 vg and above. Additionally, co-injection of immunodominant peptides from the transgene product, along with AAV8, modulates the immune response at all AAV doses tested. Taken together, our data suggest that injection of AAV8 in the subretinal space induces proinflammatory peripheral T-cell responses to the transgene product that can be modulated by the subretinal associated immune inhibition (SRAII) mechanism. ### Competing Interest Statement Please note that a declaration of invention has been patented. However, with respect to the classical definition of declaration of interest rules, we indicated in the manuscript that Authors have no conflict of interest to declare. Indeed, we have no affiliation with a yearly financial benefit exceeding $10,000, no ownership of a company with related interests, and no research funding by a company with related interests.