Defective Lentiviral Vectors Are Efficiently Trafficked by HIV-1 and Inhibit Its Replication

Abstract

Gene therapy against HIV infection should involve vector-mediated delivery of anti-HIV therapeutic genes into T-lymphocytes and macrophages or, alternatively, hematopoietic progenitors. Transduction of mature cells with defective vectors would have limited success because the vector would disappear with cell turnover. However, if a vector could be trafficked by wild-type HIV, initial transduction of a majority of the population would not be required, as the vector would be able to spread. We describe HIV-1-based lentiviral vectors that are efficiently packaged and trafficked by HIV-1, allowing a small number of cells initially transduced to spread the vector within a nontransduced cell population. We examined whether the presence or absence of the rev gene and the Rev-responsive element (RRE) would have a noticeable effect on the ability of lentiviral vectors to be trafficked and to inhibit HIV-1 replication. We found that replacement of rev/RRE with a constitutive transport element from Mason-Pfizer monkey virus had no apparent effect on trafficking and did not change the intrinsic inhibitory abilities of the vectors. We also constructed a rev/RRE-independent HIV-1-derived vector carrying a trans-dominant negative mutant of HIV-1 Rev, RevM10. This vector was less efficiently trafficked by HIV-1 and, despite the presence of an anti-HIV-1 gene, RevM10, was less efficient at inhibiting HIV-1 replication when introduced into a target T-cell population.

HIV-1-based defective lentiviral vectors efficiently transduce human monocytes-derived macrophages and suppress replication of wild-type HIV-1

“…We found that the replication of HIV-1 in the transduced MDM was significantly inhibited when compared to untransduced normal MDM. These data demonstrate a DLV-mediated inhibitory effect on HIV-1 infection in primary culture of human MDM (using vectors which lack any designated anti-HIV-1 insert sequence), which extend our previous findings in dividing cells [32].…”

“…DLV-mediated interference of HIV-1 replication is a recently described phenomenon that has been demonstrated in transduced primary lymphocytes and CD4+ T cell lines by several other investigators [32,[41][42][43][44][45][46][47]. There are several potential mechanisms that may account for this antiviral effect: (a) TAR and RRE decoy effects of the vectors at both the transcriptional and post-transcriptional levels [45]; (b) competition of the vectors for substrates necessary for reverse transcription and RNA encapsidation [44,46]; and (c) co-packaging and/or dimerization of wild-type and DLV genomes, resulting in the generation of defective virus particles [48].…”

“…Previous studies have shown that defective HIV-1-based vectors can be mobilized by wildtype HIV-1, and subsequently trafficked to previously untransduced cells within a culture [32,41,[44][45][46]. This phenomenon remains relatively poorly explored, but its existence suggests that it may be possible to design a gene therapy strategy in which one might be able to protect a large number of virus-susceptible cells by transducing a much smaller initial subset of cells (either ex vivo or in vivo).…”

“…We have previously described the construction of defective lentiviral vectors (DLV) based on a modified HIV-1 genome [13,32]. We have used these vectors to develop an optimized protocol for the efficient transduction of primary human MDM.…”

Lentiviral transduction of human T-lymphocytes with a RANTES intrakine inhibits human immunodeficiency virus type 1 infection

“…The results demonstrated that intrakine genes can indeed be efficiently transduced into human T cells with lentiviral vectors. Lentiviral vectors were also reported to transduce other anti-HIV genes into T cells for potential clinical application, 34,35 although the safety concerns for lentiviral vectors still remain. 36 The intrakine that blocks HIV entry is unique, since other anti-HIV gene therapy approach is targeted at the replication of HIV after virus infection of host T cells.…”