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Obliterative bronchiolitis (OB) is a form of chronic rejection after lung transplantation. Lentiviral vectors (LVs) facilitate long-term gene transduction in many tissues and organs. We hypothesized that lentiviral gene transfer of interleukin (IL)-10, a potent immune-modulating cytokine, to the lung could modulate the alloimmune responses in the lung after transplantation. C57BL6 mice received LVs encoding luciferase, enhanced green fluorescent protein (eGFP), or human IL-10 (huIL-10) through airways and underwent repeated bioluminescent imaging, immunofluorescence imaging, or ELISA of lung tissues, respectively. Luciferase activities peaked at day 7 and were stable after day 28 to over 15 months. eGFP staining demonstrated LV-mediated gene transduction mainly in alveolar macrophages. LV-huIL-10 delivery resulted in stable long-term expression of huIL-10 in the lung tissue (average 3.66 pg/mg at 1 year). Intrapulmonary allograft tracheal transplantation (BALBc→C57BL6) was used as a model of OB. LV-huIL-10 or LV-eGFP were delivered 7 days before transplantation and compared with no LV-transfection group. Allograft airways at day 28 were almost completely obliterated in all the groups. However, at day 42, allograft airways treated with LV-huIL-10 showed a spectrum of attenuation in airway fibrosis ranging from complete obliteration through bubble-like partial opening to complete patency with epithelial coverage in association with a significantly reduced obliteration ratio compared with the other groups (p0.05). In conclusion, lentivirus-mediated gene transduction is useful in achieving long-term transgene expression in the lung. Long-term IL-10 expression has the potential to attenuate allograft airway obliteration. LV-mediated gene therapy could be a useful strategy to prevent or treat OB after lung transplantation.

Adoptive T cell therapy is aimed at overcoming constraints of the endogenous immune response. In patients with malignancies, this approach is based on the possibility of administering sufficient numbers of tumor-reactive lymphocytes under conditions in which they will promote a therapeutic response. Although this strategy is potentially applicable to a vast number of malignancies, its efficacy, to date, has been limited. This is likely related to several factors including an insufficient persistence and reactivation of infused cells, insufficient tumor infiltration, and the presence of an immunosuppressive environment. Here, we review the importance of pretransplantation host conditioning and posttransplantation strategies that have been shown to contribute to the therapeutic efficacy of infused T lymphocytes.

The applicability of immunotherapy would be dramatically broadened to a greater number of recipients if direct “off-the-shelf” products could be engineered to engender functionally potent immune responses against true “self”-tumor antigens. This would obviate the need for ex vivo culture of dendritic cells or T cells on a patient-by-patient basis, for example. The carcinoembryonic antigen (CEA) is a glycoprotein expressed in normal gut epithelium that is up-regulated in the majority of colon cancers, non-small cell lung cancers, and half of all breast cancers. Such properties make CEA an excellent and important target for cancer immunotherapy. In this study, we show stabilization of 14-day established s.c. mGC4CEA tumors in human CEA (huCEA) transgenic mice following two direct low-dose injections of 0.15 × 106 transducing units of a lentiviral vector (LV) that directs expression of huCEA (LV-huCEA). This stabilization result was reproducible and detailed analyses including antibody assays, multiplex cytokine analyses on unstimulated splenocytes, lymph node cell characterizations, tetramer staining, and immunofluorescence staining of tumor sections showed that this outcome correlated with both a cellular and humoral immune response. Similar tumor outcomes were not seen when mice were vaccinated with a control LV that engineered expression of enGFP only. The long-term potency of this vaccination strategy was also studied and revealed the requirement for maintenance of tumor antigen-specific immunity for efficient tumor control. These data support the use of direct injections of low doses of LV-huCEA for enhancement of tumor immunotherapy directed against CEA. [Mol Cancer Ther 2009;8(3):OF692–11]

Interleukin (IL)-10 is an important immunoregulatory cytokine shown to impact inflammatory processes as manifested in patients with multiple sclerosis (MS) and in its animal model, experimental autoimmune encephalomyelitis (EAE). Several lines of evidence indicate that the effectiveness of IL-10-based therapies may be dependent on the timing and mode of delivery. In the present study we engineered the expression of IL-10 in human adipose-derived mesenchymal stem cells (Adi-IL-10-MSCs) and transplanted these cells early in the disease course to mice with EAE. Adi-IL-10-MSCs transplanted via the intraperitoneal route prevented or delayed the development of EAE. This protective effect was associated with several anti-inflammatory response mechanisms, including a reduction in peripheral T-cell proliferative responses, a decrease in pro-inflammatory cytokine secretion as well as a preferential inhibition of Th17-mediated neuroinflammation. In vitro analyses revealed that Adi-IL-10-MSCs inhibited the phenotypic maturation, cytokine production and antigen presenting capacity of bone marrow-derived myeloid dendritic cells, suggesting that the mechanism of action may involve an indirect effect on pathogenic T-cells via the modulation of antigen presenting cell function. Collectively, these results suggest that early intervention with gene modified Adi-MSCs may be beneficial for the treatment of autoimmune diseases such as MS.

Cell cycle entry is commonly considered to positively regulate HIV-1 infection of CD4 T cells, raising the question as to how quiescent lymphocytes, representing a large portion of the viral reservoir, are infected in vivo. Factors such as the homeostatic cytokine IL-7 have been shown to render quiescent T cells permissive to HIV-1 infection, presumably by transiently stimulating their entry into the cell cycle. However, we show here that at physiological oxygen (O 2 ) levels (2–5% O 2 tension in lymphoid organs), IL-7 stimulation generates an environment permissive to HIV-1 infection, despite a significantly attenuated level of cell cycle entry. We identify the IL-7–induced increase in Glut1 expression, resulting in augmented glucose uptake, as a key factor in rendering these T lymphocytes susceptible to HIV-1 infection. HIV-1 infection of human T cells is abrogated either by impairment of Glut1 signal transduction or by siRNA-mediated Glut1 down-regulation. Consistent with this, we show that the susceptibility of human thymocyte subsets to HIV-1 infection correlates with Glut1 expression; single-round infection is markedly higher in the Glut1-expressing double-positive thymocyte population than in any of the Glut1-negative subsets. Thus, our studies reveal the Glut1-mediated metabolic pathway as a critical regulator of HIV-1 infection in human CD4 T cells and thymocytes.

Immunotherapy against cancer basically aims at either broadly stimulating the immune system or at engineering an immune response against a targeted tumor associated antigen (TAA). In this review, we focus on the translation of immuno-gene therapy strategies into clinical trials for various cancers. Rather than being an exhaustive compendium of the literature, the focus of this article is to underline how anti-cancer immunotherapy strategies have evolved recently. Previously, studies have used different vectors to either express immuno-stimulatory molecules or a targeted TAA. Investigators are now directing efforts to both target a TAA and to stimulate the immune system by direct or viral administration of cytokines or co-stimulatory molecules. Some groups have also tried to combine genetic immunotherapy with chemotherapy, and results have been encouraging. This novel concept might open new perspectives for the treatment of patients with advanced-stage cancer.