A Rev-inducible mutant gag gene stably transferred into T lymphocytes: an approach to gene therapy against human immunodeficiency virus type 1 infection.

One strategy for somatic gene therapy for human immunodeficiency virus type 1 (HIV-1) infection is based on the regulated expression of dominant negative mutants of the HIV-1 gag gene. To limit expression of the mutant Gag polypeptide to HIV-1-infected cells, we have constructed a replication-defective retroviral vector that contains a Rev-responsive element. By using this construct we have obviated problems that can be associated with constitutive expression of an exogenous gene, an important step toward developing a human therapy. In uncloned T lymphocytes infected (transduced) with this retroviral construct, HIV-1 replication was inhibited by 94% with a concomitant decrease in the cytopathic effects of the virus. In addition, simian immunodeficiency virus (SIV) replication was also shown to be significantly inhibited, suggesting that this mutant Gag protein may have antiviral efficacy against a broad range of primate lentiviruses and that an SIV/macaque model can be used for further in vivo studies. These results have important implications in assessing the potential of somatic gene therapy in the treatment of HIV-1 infection.