Herpes simplex virus mediated gene transfer to primate ocular tissues

We evaluated the feasibility of delivering a gene into monkey eyes using a replication-competent herpes simplex virus (HSV) type 1 ribonucleotide redu ctase mutant (hrR3) expressing the Escherichia coil lacZ gene. To determine the efficiency of in vitro HSV-mediated gene transfer, cultured human trab ecular meshwork (HTM) and human ciliary muscle (HCM) cells were infected wi th hrR3 and beta-galactosidase activity was measured histochemically. Six c ynomolgus monkey eyes received viral injections into the anterior chamber ( 2 x 10(7) pfu) and/or the vitreous (5 x 107 pfu), and the distribution of c ells expressing lacZ was evaluated. In vitro, both cultured HTM and HCM cel ls displayed multiplicity-dependent beta-galactosidase activity. In vivo, i ntracameral and/or intravitreal injection resulted in transgene expression in TM cells and in non-pigmented ciliary epithelial cells (NPE), but not in CM cells. Transgene expression was also detected in retinal pigmented epit helial (RPE) cells and sporadic retinal ganglion cells (RGC) in eyes receiv ing virus intracamerally and intravitreally respectively. We observed signi ficant inflammation in the anterior chamber, TM and CM in virus-injected ey es, along with mild vitritis and retinitis. This study demonstrates success ful gene transfer using hrR3 as a vector in human ocular cells and in ocula r tissues in living monkeys. Further investigation of the etiology of the i nflammatory response, possible cytotoxicity, and limited duration of transg ene expression is necessary in order to make this technique clinically appl icable. (C) 1999 Academic Press.