Inhibition of human immunodeficiency virus (HIV-1) replication in SupT1 cells transduced with an HIV-1 LTR-driven PKR cDNA construct

Current strategies against the human immunodeficiency virus type 1 (HIV-I), including nucleoside analogues and protease inhibitors, have limited effec tiveness as shown by the evolution of resistant retroviral strains and the presence of latent HIV-I reservoirs. Therefore, it is necessary to look bey ond anti-retroviral strategies and to rely on the body's immune system to i nhibit HIV-1 replication. In this study, we approach the inhibition of HIV- 1 replication by upregulation of the antiviral pathway that is natural to m ammalian cells. Vectors were constructed which were capable of transferring the antiviral enzyme, p68 kinase (PKR), into target SupT1 lymphoblastoid c ells under HIV-1 LTR transcriptional regulation via a retroviral-mediated s huttle system. We report a significant inhibition of HTV-1 replication in H IV-I LTR-PKR cDNA transduced clones (105-10 : 239 and 106-4 : 560) expressi ng different PKR levels as measured by inhibition of HIV-I induced syncytia formation and HIV-1 reverse transcriptase activity. Whereas the expression of PKR in parental vector transduced clone (N2-20P) is down-regulated 48 h after HIV-1 infection, the two transduced clones tone with PKR in the forw ard orientation and one in the reverse orientation demonstrate increased PK R expression through 96 h post-infection, concomitant with an increase in e IF-2 alpha phosphorylation and an increase in NF-kappa B activity at 72 h p ostinfection. These results demonstrate that the overexpression of PKR can inhibit HTV-1 replication and confirm the involvement of PKR in the IFN-ass ociated antiviral pathway against HIV-1 infection. Finally, the treatment o f the transduced clone 106-4 : 560 with AZT resulted in complete inhibition of HIV-1 replication.