Abstract
Abstract: :
Purpose: Intracameral injection of adenoviral vectors (AdV) has been used to transduce cells in the anterior segment. Unfortunately, the consequent expression of the encoded gene product is usually transient (1–3 weeks), likely due to immune responses to the viral particles and foreign transgene products. We determined whether treatment of the mouse with an anti–CD40L antibody could suppress the immune response and prolong the expression of an AdV.GFP vector injected into the anterior segment of the mouse. Methods: Adult male Balb/c mice receiving a single unilateral intracameral injection (2 µL with 5.5×108 pfu/µL) of an Ad5 expression vector encoding green fluorescent protein (GFP) were randomly divided into two groups. The antibody–treated group received anti–CD40L antibody (MR–1; 0.5 mg/mouse, intraperitoneal injection) 1 day prior and on days 0, 1, 2, 5, 9, and 14 following AdV.GFP injection. The control group was untreated. GFP expression in the anterior chamber was evaluated at different time points under a UV light in vivo as well as by fluorescence microscopy after the eyes were enucleated, fixed, and sectioned. Results: In the control group, GFP expression peaked at 3–7 days and completely disappeared 4 weeks after injection. In the antibody–treated group, GFP fluorescence was maintained at a high level from Day 3 lasting more than 3 months. Examination of ocular sections indicated high GFP expression in the trabecular meshwork, with some expression also in the corneal endothelium and iris epithelium. Intracameral injection of AdV caused a mild and transient iris hyperemia within the initial 3–5 days. Anti–CD40L antibody treatment did not cause any observable clinical symptoms in the animals. Conclusions: Treatment of the mouse with an anti–CD40L antibody enhanced the intensity and duration of GFP expression in the anterior segment after intracameral injection of AdV.GFP. These results suggest that immunosupression with the anti–CD40L antibody can decrease immune responses and substantially lengthen the AdV transgene expression in the eye.
Keywords: trabecular meshwork • adenovirus • gene/expression