VIRION-TARGETED VIRAL INACTIVATION OF HUMAN-IMMUNODEFICIENCY-VIRUS TYPE-1 BY USING VPR FUSION PROTEINS

Inactivation of progeny virions with chimeric virion-associated protei ns represents a novel therapeutic approach against human immunodeficie ncy virus (HIV) replication. The HIV type 1 (HIV-1) Vpr gene product, which is packaged into virions, is an attractive candidate for such a strategy. In this study, we developed Vpr-based fusion proteins that c ould be specifically targeted into mature HIV-1 virions to affect thei r structural organization and/or functional integrity. Two Vpr fusion proteins were constructed by fusing to the first 88 amino acids of HIV -1 Vpr the chloramphenicol acetyltransferase enzyme (VprCAT) or the la st 18 C-terminal amino acids of the HIV-1 Vpu protein (VprIE), These V pr fusion proteins were initially designed to quantify their efficienc y of incorporation into HIV-1 virions when produced in cis from the pr ovirus, Subsequently, CD4(+) Jurkat T-cell lines constitutively expres sing the VprCAT or the VprIE fusion protein were generated with retrov iral vectors. Expression of the VprCAT or the VprIE fusion protein in CD4(+) Jurkat T cells did not interfere,vith cellular viability or gro wth but conferred substantial resistance to HIV replication. The resis tance to HIV replication was more pronounced in Jurkat-VprIE cells tha n in Jurkat-VprCAT cells. Moreover, the antiviral effect mediated by V prIE was dependent on an intact p6(gag) domain, indicating that the im pairment of HIV-1 replication required the specific incorporation of V pr fusion protein into virions. Gene expression, assembly, or release was not affected upon expression of these Vpr fusion proteins. Indeed, the VprIE and VprCAT fusion proteins were shown to affect the infecti vity of progeny virus, since HIV virions containing the VprCAT or the VprIE fusion proteins were, respectively, 2 to 3 times and 10 to 30 ti mes less infectious than the wild-type virus. Overall, this study demo nstrated the successful transfer of resistance to HIV replication in t issue cultures by use of Vpr-based antiviral genes.