1,721,060 research outputs found
Ten years of gene therapy for primary immuno deficiencies
No full textGene therapy with hematopoietic stem cells (HSC) is an attractive therapeutic strategy for several forms of primary immunodeficiencies. Current approaches are based on ex vivo gene transfer of the therapeutic gene into autologous HSC by vector-mediated gene transfer. In the past decade, substantial progress has been achieved in the treatment of severe combined immundeficiencies (SCID)-X1, adenosine deaminase (ADA)-deficient SCID, and chronic granulomatous disease (CGD). Results of the SCID gene therapy trials have shown long-term restoration of immune competence and clinical benefit in over 30 patients. The inclusion of reduced-dose conditioning in the ADA-SCID has allowed the engraftment of multipotent gene-corrected HSC at substantial level. In the CGD trial significant engraftment and transgene expression were observed, but the therapeutic effect was transient. The occurrence of adverse events related to insertional mutagenesis in the SCID-X1 and CGD trial has highlighted the limitations of current retroviral vector technology. For future applications the risk-benefit evaluation should include the type of vector employed, the disease background and the nature of the transgene. The use of self-inactivating lentiviral vectors will provide significant advantages in terms of natural gene regulation and reduction in the potential for adverse mutagenic events. Following recent advances in preclinical studies, lentiviral vectors are now being translated into new clinical approaches, such as Wiskott-Aldrich Syndrome
The immune response to lentiviral-delivered transgene is modulated in vivo by transgene expressing antigen presenting cells but not by CD4+CD25+ regulatory T cells
No full textSystemic delivery of lentiviral vector (LV) in immunocompetent mice leads to efficient in vivo cell transduction and expression of the encoded protein under the control of the ubiquitous promoter of human cytomegalovirus (CMV). However, antitransgene immune response results in clearance of transduced cells 4 weeks after injection. T regulatory cells (Tregs), which have been demonstrated to control immune responses in vivo, were tested for their ability to suppress antitransgene response leading to stable long-term expression. Adoptive transfer of natural CD4(+)CD25(+) Tregs (nTregs) isolated from wild type (wt) mice or from transgene tolerant transgenic (tg) mice did not suppress the antitransgene immune response after LV delivery. These data demonstrate that neither increasing the endogenous pool of natural Tregs nor transferring nTregs selected in a transgene-expressing thymus can modulate the immune response and mediate sustained transgene expression. Conversely, adoptive transfer of antigen-presenting cells (APCs) isolated from transgene-tolerant tg mice efficiently reduced the immune response leading to stable LV-encoded protein expression in vivo. Reduction of CD8(+) effector T cells was observed in LV-treated mice coinjected with transgene-expressing APCs compared with control mice. These data indicate that antitransgene immune response can be modulated by transgene-expressing APCs possibly through deletion of effector T cells
SAP controls the cytolytic activity of CD8+ T cells against EBV-infected cells
No full textThe adaptor protein SAP regulates signaling through signaling lymphocytic activation molecule (SLAM)-family receptors expressed on T and natural killer (NK) cells. In patients affected by X-linked lymphoproliferative (XLP) disease, mutations in the SH2D1A gene result in defective lytic activity. However, the mechanism by which SAP controls cytotoxic activity remains unclear. T-cell-receptor (TCR) activation of CD8(+) cytotoxic T cells (CTLs) results in down-regulation of SAP, suggesting that this protein is involved in early activation events. Here, we show that SAP-deficient CTLs from patients with XLP and hemophagocytic lymphohistiocytosis (HLH) display a specific lytic defect against autologous and allogeneic Epstein-Barr virus (EBV)-positive B cells. This defect is associated with the defective polarization of 2B4, perforin, and lipid rafts at the contact area of CTLs with EBV-positive targets. Blockade of 2B4 in normal CTLs reproduces the defects in lysis and polarization observed in SAP-deficient CTLs. Expression and regulation of the SLAM-family receptors SLAM, CD84, and 2B4, as well as the lytic effectors perforin and granzyme-B are normal in SAP-deficient CTLs. In addition, TCR stimulation leads to normal proliferation and production of interleukin 2 (IL-2), IL-4, and interferon-gamma (IFN-gamma). These results demonstrate that the SAP/2B4 pathway plays a key role in CTL lytic activity against EBV-positive targets by promoting the polarization of the lytic machinery
Insulin B chain 9-23 gene transfer to hepatocytes protects from type 1 diabetes by inducing Ag-specific FoxP3+ Tregs
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HUMAN INSULIN PRODUCTION AND AMELIORATION OF DIABETES IN MICE BY ELECTROTRANSFER-ENHANCED PLASMID DNA GENE TRANSFER TO THE SKELETAL MUSCLE.
No full textGeneration of potent and stable human CD4+ T regulatory cells by activation-independent expression of FOXP3
No full textHuman insulin production and amelioration of diabetes in mice byelectrotransfer-enhanced plasmid DNA gene transfer to the skeletal muscle.
No full textA first-line gene therapy for type 1 diabetes should be based on a safe procedure to engineer an accessible tissue for insulin release. We evaluated the ability of the skeletal muscle to release human insulin after electrotransfer (ET)-enhanced plasmid DNA injection in mice. A furin-cleavable proinsulin cDNA under the CMV or the MFG promoter was electrotransferred to immune-incompetent mice with STZ-induced severe diabetes. At 1 week, mature human insulin was detected in the serum of 17/20 mice. After an initial peak of 68.5 ± 34.9 μU/ml, insulin was consistently detected at significant levels up to 6 weeks after gene transfer. Importantly, untreated diabetic animals died within 3 weeks after STZ, whereas treated mice survived up to 10 weeks. Fed blood glucose (BG) was reduced in correspondence with the insulin peak. Fasting BG was near-normalized when insulin levels were 12.9 ± 5.3 (CMV group, 2 weeks) and 7.7 ± 2.6 μU/ml (MFG group, 4 weeks), without frank hypoglycemia. These data indicate that ET-enhanced DNA injection in muscle leads to the release of biologically active insulin, with restoration of basal insulin levels, and lowering of fasting BG with increased survival in severe diabetes. Therefore the skeletal muscle can be considered as a platform for basal insulin secretion
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