Inhibition of human immunodeficiency virus replication and growth advantage of CD4(+) T cells and monocytes derived from CD34(+) cells transduced with an intracellular antibody directed against human immunodeficiency virus type 1 Tat

Current clinical gene therapy protocols for the treatment of human immunode ficiency virus type 1 (HIV-1) infection involve the ex vivo transduction an d expansion of CD4(+) T cells derived from HIV-positive patients at a late stage in their disease (CD4(+) cell count <400 cells/mm(3)). We examined th e efficiency of transduction and transgene expression in adult bone marrow (BM)- and umbilical cord blood (UCB)-derived CD34(+) cells induced to diffe rentiate into T cells and monocytes in vitro with an MuLV-based vector enco ding the neomycin resistance gene and an intracellular antibody directed ag ainst the Tat protein of HIV-1 (sFvtat1-C-kappa). The expression of the mar ker gene and the effects of antiviral construct on subsequent challenge wit h monocytotropic and T cell-tropic HIV-1 isolates were monitored in vitro i n purified T cells and monocytes generated in culture from the transduced C D34(+) cells. Transduction efficiencies of CD34(+) cells ranged between 22 and 27%, Differentiation of CD34(+) cells into T cells or monocytes was not significantly altered by the transduction process. HIV-1 replication in mo nocytes and CD4(+) T cells derived from CD34(+) cells transduced with the i ntracellular antibody gene was significantly reduced in comparison with the degree of HIV replication seen in monocytes and CD4(+) T cells derived fro m CD34(+) cells transduced with the neomycin resistance gene alone. Further , T cells and monocytes derived from CD34(+) cells transduced with the intr acellular antibody gene were demonstrated to express the sFvtat1-C-kappa tr ansgene by RT-PCR and had a selective growth advantage in cultures that had been challenged with HIV-1, These data demonstrate that sFvtat1-C-kappa in hibits HIV-1 replication in T cells and monocytes developing from CD34(+) c ells and supports the continuing development of a stem cell gene therapy fo r the treatment of HIV-1 infection.