To date adeno-associated viral (AAV) vectors are the only gene therapy vectors that have been shown to efficiently transduce photoreceptor cells and have thus become the most commonly used vector for ocular transduction. Various AAV serotypes have been evaluated in the eye, the first of which was AAV2, which is able to transduce photoreceptors, retinal pigment epithelium (RPE) and retinal ganglion cells. AAV serotypes 1 and 4, as well as AAV2 pseudotyped with these capsids, only transduce the RPE. AAV serotype 5 and AAV2/5 transduce the photoreceptors as well as RPE, but not retinal ganglion cells. Here, we assessed the capacity of the novel serotype AAV2/8 to transduce various ocular tissues of the adult murine retina by administering AAV2/8 green fluorescent protein intravitreally, subretinally and intracamerally. We also determined the kinetics and efficiency of self-complementary AAV (scAAV) vectors of serotypes 2/2, 2/5 and 2/8 and compared them with single-stranded AAV (ssAAV). We found that ssAAV2/8 transduces photoreceptors and RPE more efficiently than ssAAV2/2 and ssAAV2/5, and that scAAV2/8 had faster onset and higher transgene expression than ssAAV2/8. This improved transduction efficiency might facilitate the development of improved gene therapy protocols for inherited retinal degenerations, particularly those caused by defects in photoreceptor-specific genes.

Autoimmune posterior uveitis is a chronic, potentially blinding inflammatory disease of the eye. It is commonly treated with immunosuppressive drugs that have adverse long-term effects. Advances in gene transfer techniques have enabled long-term, stable transduction of retinal cells following subretinal injection with adeno-associated viral (AAV) vectors. Here we report for the first time that subretinal injection of rAAV-2 encoding murine IL-10 into the retina of C57BL/6 mice significantly decreases the median experimental autoimmune uveitis (EAU) disease severity. This protection is shown to be due to a decrease in the number and activation status of infiltrating monocytes during EAU, as determined by costimulatory molecule expression and nitrotyrosine detection. No differences within splenocyte proliferative responses or serum antibody levels were detected, emphasizing the potential of gene therapy strategies in ameliorating autoimmune responses in local microenvironments without unwanted systemic effects.

Uveitis is a sight threatening inflammatory disorder that remains a significant cause of visual loss. We investigated lentiviral gene delivery of IL-1ra or IL-10 to ameliorate murine endotoxin-induced uveitis (EIU). An HIV-1-based vector containing the mIL-1ra or mIL-10 cDNA demonstrated high expression of biologically active cytokine. Following administration of Lenti.GFP into the anterior chamber, transgene expression was observed in corneal endothelial cells, trabecular meshwork and iris cells. To treat EIU, mice were injected with Lenti.IL-1ra, Lenti.IL-10 or a combination of these. EIU was induced 14 days after vector administration and mice were culled 12 h following disease induction. Lenti.IL-1ra or Lenti.IL10 treated eyes showed significantly lower mean inflammatory cell counts in the anterior and posterior chambers compared with controls. The aqueous total protein content was also significantly lower in treated eyes, demonstrating better preservation of the blood-ocular barrier. Furthermore, the treated eyes showed less in vivo fluorescein leakage from inner retinal vessels compared with controls. The combination of both IL-1ra and IL-10 had no additive effect. Thus, lentiviral gene delivery of IL-1ra or IL-10 significantly reduces the severity of experimental uveitis, suggesting that lentiviral mediated expression of immunomodulatory genes in the anterior chamber offers an opportunity to treat uveitis.