SELECTIVE GENE-TRANSFER INTO THE LIVER OF NONHUMAN-PRIMATES WITH E1-DELETED, E2A-DEFECTIVE, OR E1-E4 DELETED RECOMBINANT ADENOVIRUSES

Preclinical studies were designed to investigate the feasibility and s afety of recombinant adenoviruses transduced into the hepatic artery o f nonhuman primates. The vectors used are recombinant adenoviruses del eted in El and contain either a temperature-sensitive mutation in the E2a gene, which encodes a defective DNA-binding protein at nonpermissi ve temperatures, or a deletion of the E4 region, including open readin g frame (ORF) 6. Six 8- to 10-kg baboons underwent femoral artery cann ulation, and angiographic techniques were used to introduce vector sel ectively into either a portion of the right lobe of the liver via a br anch of the right hepatic artery or the common hepatic artery. Necrops ies were performed at 4, 29, or 61 days, Serial sequential liver biops ies were performed in the baboons that survived 29 or 61 days, In the 2 baboons with vector transduction into the right hepatic artery, X-Ga l histochemical analysis of the liver showed evidence of quantitativel y increased gene transfer in the targeted lobe; however, gene transfer was present throughout the liver. Quantitative analysis of histopatho logy showed that portal inflammation was present throughout both liver s transduced with the highest dose of vector, No differences were seen in the level of portal inflammation in targeted and untargeted lobes despite the observed qualitative and quantitative differences in gene expression. Southern blot analysis of total cellular DNA isolated from targeted and nontargeted lobes showed similar levels of viral DNA thr oughout the liver. Polymerase chain reaction (PCR) analysis was able t o detect viral DNA sequence in gonads and brain as well as many ether tissues in baboons treated with high-dose vector. In baboons treated w ith lower doses of an E1-E4 deleted vector expressing the human ornith ine transcarbamylase (OTC) gene, DNA was detectable by nested PCR in l iver but not gonads at days 29 and 61, The data suggest that intraarte rial administration of recombinant adenoviral E1-E4 deleted vector is feasible and safe. At high doses of vector, widespread dissemination o f vector DNA is seen. At low doses, hepatic gene transfer is not assoc iated with vector DNA dissemination to gonads.