Antitat gene therapy: a candidate for late-stage AIDS patients

Antitat is an autoregulated gene expressing an inhibitory RNA with dual function: it sequesters the Tat protein by polymeric-TAR and blocks the translation of the Tat messenger RNA by antisense-Tat. Using human T cell lines and peripheral blood lymphocytes as the in vitro target, we have previously shown that antitat is an effective long-term suppressor of HIV-1, including 'field' isolates. To assess the efficacy of this inhibitory gene better in the setting of an infected individual with late-stage AIDS, we examined its antiviral activity in an in vivo established infection. Peripheral blood mononuclear cells isolated from AIDS patients were transduced with replication defective retroviral vectors carrying the antitat gene. In the absence of cell selection, the antitat gene blocked virus replication and allowed infected CD4+ T cells to expand in culture. These results suggest that antitat gene therapy may be beneficial to block HIV-1 replication and reconstitute the immune system of late-phase AIDS patients. We introduced a new parameter, CRF, which defines the effectiveness of the ex vivo gene therapy treatment of AIDS patients. Antitat treatment was efficient in cells of all patients regardless of viral quasispecies, however, it was most potent in severely immunocompromised individuals.