Ballistic transfer of minimalistic immunologically defined expression constructs for IL4 and CTLA4 into the corneal epithelium in mice after orthotopic corneal allograft transplantation.

Background: Experiments were performed to determine whether corneal epithelium transfected with minimalistic immunologically defined expression constructs for the extracellular fragment of CTLA4 and for interleukin-4 (IL-4) or interleukin-10 (IL-10) is able to modulate an allospecific immune response after orthotopic corneal grafting in mice. Methods: Six groups of BALB/c (H-2d) mice received a C3H (H-2k) corneal graft and dexamethasone eye drops until day 11. Five groups of BALB/c mice had gold particles delivered into the corneal epithelium by Gene Gun on day 10 after transplantation. In four groups, minimalistic immunologic-ally defined gene expression (MIDGE) vectors were delivered into the corneal epithelium by ballistic transfer. The levels of expressed IL-4 and IL-10 were determined by an enzyme-linked immunosorbent assay (ELISA) in shock-frozen homogenized corneas. The expression kinetics of Gene-Gun-transfected corneas were determined by measuring luciferase in lysed whole corneas at different time intervals. Results: Luciferase expression was detectable during the first 5 days following transfection. ELISA was used to determine IL-4 and IL-10 expression in corneal tissue 36 h after transfection. Ballistic IL-4 and CTLA4 gene transfer significantly prolonged corneal graft survival in comparison with the gold-treated control group and the IL-10-treated group. Conclusion: The beneficial effect of IL-4 and CTLA4, but not IL-10 gene transfer into the corneal epithelium by MIDGE vectors was demonstrated for the first time in corneal transplantation. [ABSTRACT FROM AUTHOR]