Adenovirus-mediated gene transfer to the ocular surface epithelium

Gene transfer to the ocular surface epithelium is of potential therapeutic value. It was determined whether a reporter gene can be introduced into the ocular surface epithelium in vitro (human cell lines), ex vivo (human tissues), and in vivo (rats) by treating with a recombinant, replication-deficient, adenovirus type 5. Human and conjunctival cell lines were cultured with various multiplicities of infection (MOI; 3.2 x 10^-5-5 x 10^-1) of adenovirus vector (Ad5:Adex1CAlacZ) containing the reporter gene lacZ (1-3-2.0 x 10⁴ PFU ml^-1). The ex vivo study used human corneal and conjunctival tissues obtained from an eye bank and during surgery. Non- specific upregulation of inflammatory cytokines of conjunctival epithelium infected by AdS was assayed and its suppression by steroids. For the in vivo study, Ad5 (5 x 10⁵ PFU, 5-10 μl) was applied to the eyes of 8-12-week-old cotton rats, which were enucleated 24 and 48 hr later. The maximum lacZ expression in vitro was demonstrated in the corneal epithelial cell line at 7 days (1 x 10^- MOI) and conjunctival epithelial cell line at 2 days (4 x 10^{- 4} MOI). Furthermore, lacZ was also expressed in the superficial corneal and conjunctival epithelium in the ex vivo study. IL-6, 11-8, and ICAM-1 expression from conjunctival epithelium by Ad5 was significantly inhibited by treatment with betamethasone (BM). For the in vivo study, only the conjunctival epithelium demonstrated β-Gal activity at 24 and 48 hr after application. These data indicate that adenovirus vector is capable of directly delivering gene to the corneal and conjunctival epithelium, suggesting a variety of possible gene therapy uses. The concomitant application of steroid eye drops may avoid inflammation.