Selective survival of peripheral blood lymphocytes in children with HIV-1 following delivery of an anti-HIV gene to bone marrow CD34+ cells

Abstract

Two HIV-1-infected children on antiretroviral therapy were enrolled into a clinical study of retroviral-mediated transfer of a gene that inhibits replication of HIV-1, targeting bone marrow CD34+ hematopoietic stem/progenitor cells. Two retroviral vectors were used, one encoding a "humanized" dominant-negative REV protein (huM10) that is a potent inhibitor of HIV-1 replication and one encoding a nontranslated marker gene (FX) to serve as an internal control for the level of gene marking. Peripheral blood mononuclear cells (PBMC) containing the huM10 gene or FX gene were detected by quantitative PCR at frequencies of approximately 1/10,000 in both subjects for the first 1-3 months following re-infusion of the gene-transduced bone marrow, but then were at or below the limits of detection (<1/1,000,000) at most times over 2 years. In one patient, a reappearance of PBMC containing the huM10 gene, but not the FX gene, occurred concomitant with a rise in the HIV-1 viral load during a period of nonadherence to the antiretroviral regimen. Unique clones of gene-marked PBMC were detected by LAM-PCR during the time of elevated HIV-1 levels. These findings indicate that there was a selective survival advantage for PBMC containing the huM10 gene during the time of increased HIV-1 load.

A Mutant Tat Protein Provides Strong Protection from HIV-1 Infection in Human CD4+T Cells

“…The RevM10 mutant protein is dominant negative because it retains the ability to bind the HIV-1 Rev response element (RRE) but is unable to promote CRM1 (chromosome region maintenance 1)-mediated export of the viral mRNA from the nucleus, thereby inhibiting HIV-1 replication (Malim et al, 1991;Stauber et al, 1998). RevM10 mutant, the first trans-dominant negative protein to undergo a pilot clinical trial in HIV-1-infected patients (Woffendin et al, 1996;Ranga et al, 1998), was beneficial to cell survival in the context of HIV infection (Podsakoff et al, 2005). A human engineered TRIM5 (tripartite motif 5)-cyclophilin protein introduced into primary CD4 + T cells and macrophages provided extraordinary protection from HIV-1 infection in vitro and in immunecompromised mice (Neagu et al, 2009).…”

Gene Regulatable Lentiviral Vector System

“…The TdReV named RevM10 is a derivative of HIV-1 Rev in which two amino acid mutations are introduced in the C-terminus activation domain, and hampers nuclear export of HIV-1 mRNAs via the formation of inactive multimers with WT Rev (Hope et al, 1992;Malim et al, 1989). It should be noted that RevM10 has been already tested in phase I clinical trials to treat HIV infection via transduction of the gene into CD34 + cells with MoMLV-derived retroviral vectors (Kang et al, 2002;Kitchen et al, 2011;Podsakoff et al, 2005). Although a promising approach for HIV gene therapy, constitutive expression of anti-HIV genes in the context of HIV-1-derived lentiviral vectors could encounter a problem of selfinhibition of the vector particle production, resulting in significant decrease of viral infectious titer (Mautino & Morgan, 2002b).…”

Gene Therapy for HIV-1 Infection

“…In clinical trials genetic modification of CD4 + T cells and CD34 + hematopoietic stem cells with RevM10 has been shown to be safe and provide some selective survival advantage. However, no sustained absolute accumulation of gene-modified cells and accordingly no antiviral effect was observed (Morgan et al, 2005;Podsakoff et al, 2005;Ranga et al, 1998;Woffendin et al, 1996). Furthermore, transdominant mutants of HIV-1 Tat that prevent Tat transactiviation have been developed (Fraisier et al, 1998;Pearson et al, 1990), but were never tested in clinical trials.…”