Lentiviral gene transfer to the nonhuman primate brain

Lentiviral vectors infect quiescent cells and allow for the delivery of gen es to discrete brain regions. The present study assessed whether stable len tiviral gene transduction can be achieved in the monkey nigrostriatal syste m. Three young adult Rhesus monkeys received injections of a lentiviral vec tor encoding for the marker gene beta galatosidase (beta Gal). On one side of the brain, each monkey received multiple lentivirus injections into the caudate and putamen. On the opposite side, each animal received a single in jection aimed at the substantia nigra. The first two monkeys were sacrifice d 1 month postinjection, while the third monkey was sacrificed 3 months pos tinjection. Robust incorporation of the beta Gal gene was seen in the stria tum of all three monkeys. Stereological counts revealed that 930,218; 1,192 ,359; and 1,501,217 cells in the striatum were beta Gal positive in monkeys 1 (n = 2) and 3 (n = 1) months later, respectively. Only the third monkey had an injection placed directly into the substantia nigra and 187,308 beta Gal-positive cells were identified in this animal. The injections induced only mirror perivascular cuffing and there was no apparent inflammatory res ponse resulting from the lentivirus injections. Double label experiments re vealed that between 80 and 87% of the beta Gal-positive cells were neurons. These data indicate that robust transduction of striatal and nigral cells can occur in the nonhuman primate brain for up to 3 months. Studies are now ongoing testing the ability of lentivirus encoding for dopaminergic trophi c factors to augment the nigrostriatal system in nonhuman primate models of Parkinson's disease. (C) 1999 Academic Press.