Bystander transfer of functional human CD40 ligand from gene-modified fibroblasts to B-chronic lymphocytic leukemia cells

CD40 ligand (CD40L) is a good candidate molecule for the immunotherapy of B cell malignancies including B-chronic lymphocytic leukemia (B-CLL), because it may increase the capacity of the malignant cells to present tumor antigens. However, efforts to manipulate expression of the human CD40L (hCD40L) molecule have foundered on problems associated with lack of consistent gene transfer into the malignant target cells. We now describe a new, highly reproducible method for inducing hCD40L surface expression on malignant B cells, which is dependent on intercellular transfer of the hCD40L protein from donor gene-modified fibroblasts to patient tumor cells. Ten B-CLL samples were cocultured with MRC-5 fibroblasts (a human embryonic lung cell line) previously transduced with an adenoviral vector encoding the hCD40L gene. The malignant cells expressed high levels of surface hCD40L, B7-1, B7-2, and ICAM-1 after coculture. Upregulation of B7-1 and B7-2 was cycloheximide inhibitable and was a consequence of CD40 activation. However, inhibition of protein synthesis had no effect on the ability of B-CLL cells to acquire surface expression of hCD40L. hCD40L surface expression required cell-to-cell contact, but was independent of CD40 engagement. hCD40L transfer was not mediated by membrane fusion. The transferred hCD40L was functionally intact and B-CLL cells expressing this molecule induced increased interferon-gamma production from autologous peripheral blood T lymphocytes. This approach does not use any direct gene transfer to primary leukemia cells and can readily be scaled up for production of clinical B-CLL vaccines.     

Cytochemical Study of Thymocytes and T Lymphocytes

Summary. Fetal and postnatal thymocytes and circulating T lymphocytes were evaluated for six cytochemical reactions. Acid phosphatase activity was present in a high percentage of cells in all three groups. Beta-glucuronidase and α-naphthyl acetate acid esterase were negative in the most immature fetal thymocytes, but become increasingly positive with T-cell maturation. Only the circulating lymphocytes presented a high percentage of N-acetyl beta glucosaminidase, α-naphthyl acetate esterase and α-naphthyl butyrate esterase positive cells. This study discusses the presence of these enzymes as proportional to different stages in T-cell maturation, and also of certain cytochemical phenotypes characteristic of these stages.     

Immunological Synapse Predicts Effectiveness of Chimeric Antigen Receptor Cells

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Mesenchymal Stromal Cells for Linked Delivery of Oncolytic and Apoptotic Adenoviruses to Non-small-cell Lung Cancers

Oncolytic adenoviruses (OAdV) represent a promising strategy for cancer therapy. Despite their activity in preclinical models, to date the clinical efficacy remains confined to minor responses after intratumor injection. To overcome these limitations, we developed an alternative approach using the combination of the OAdv ICOVIR15 with a replication incompetent adenoviral vector carrying the suicide gene of inducible Caspase 9 (Ad.iC9), both of which are delivered by mesenchymal stromal cells (MSCs). We hypothesized that coinfection with ICOVIR15 and Ad.iC9 would allow MSCs to replicate both vectors and deliver two distinct types of antitumor therapy to the tumor, amplifying the cytotoxic effects of the two viruses, in a non-small-cell lung cancer (NSCLC) model. We showed that MSCs can replicate and release both vectors, enabling significant transduction of the iC9 gene in tumor cells. In the in vivo model using human NSCLC xenografts, MSCs homed to lung tumors where they released both viruses. The activation of iC9 by the chemical inducer of dimerization (CID) significantly enhanced the antitumor activity of the ICOVIR15, increasing the tumor control and translating into improved overall survival of tumor-bearing mice. These data support the use of this innovative approach for the treatment of NSCLC.     

Antitumor activity of EBV-specific T lymphocytes transduced with a dominant negative TGF-beta receptor

Transforming growth factor (TGF)-beta is produced in most human tumors and markedly inhibits tumor antigen-specific cellular immunity, representing a major obstacle to the success of tumor immunotherapy. TGF-beta is produced in Epstein-Barr virus (EBV)-positive Hodgkin disease and non-Hodgkin lymphoma both by the tumor cells and by infiltrating T-regulatory cells and may contribute the escape of these tumors from infused EBV-specific T cells. To determine whether tumor antigen-specific cytotoxic T lymphocytes (CTLs) can be shielded from the inhibitory effects of tumor-derived TGF-beta, we previously used a hemagglutinin-tagged dominant negative TGF-betaRII expressed from a retrovirus vector to provide CTLs with resistance to the inhibitory effects of TGF-beta in vitro. We now show that human tumor antigen-specific CTLs can be engineered to resist the inhibitory effects of tumor-derived TGF-beta both in vitro and in vivo using a clinical grade retrovirus vector in which the dominant negative TGF-beta type II receptor (DNRII) was modified to remove the immunogenic hemagglutinin tag. TGF-beta-resistant CTL had a functional advantage over unmodified CTL in the presence of TGF-beta-secreting EBV-positive lymphoma, and had enhanced antitumor activity, supporting the potential value of this countermeasure.     

From Taxuspine X to Structurally Simplified Taxanes with Remarkable P-Glycoprotein Inhibitory Activity

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Regression of experimental medulloblastoma following transfer of HER2-specific T cells

Medulloblastoma is a common malignant brain tumor of childhood. Human epidermal growth factor receptor 2 (HER2) is expressed by 40% of medulloblastomas and is a risk factor for poor outcome with current aggressive multimodal therapy. In contrast to breast cancer, HER2 is expressed only at low levels in medulloblastomas, rendering monoclonal antibodies ineffective. We determined if T cells grafted with a HER2-specific chimeric antigen receptor (CAR; HER2-specific T cells) recognized and killed HER2-positive medulloblastomas. Ex vivo, stimulation of HER2-specific T cells with HER2-positive medulloblastomas resulted in T-cell proliferation and secretion of IFN-gamma and interleukin 2 (IL-2) in a HER2-dependent manner. HER2-specific T cells killed autologous HER2-positive primary medulloblastoma cells and medulloblastoma cell lines in cytotoxicity assays, whereas HER2-negative tumor cells were not killed. No functional difference was observed between HER2-specific T cells generated from medulloblastoma patients and healthy donors. In vivo, the adoptive transfer of HER2-specific T cells resulted in sustained regression of established medulloblastomas in an orthotopic, xenogenic severe combined immunodeficiency model. In contrast, delivery of nontransduced T cells did not change the tumor growth pattern. Adoptive transfer of HER2-specific T cells may represent a promising immunotherapeutic approach for medulloblastoma.     

Wernicke's encephalopathy: new clinical settings and recent advances in diagnosis and management

Wernicke's encephalopathy is an acute neuropsychiatric syndrome resulting from thiamine deficiency, which is associated with significant morbidity and mortality. According to autopsy-based studies, the disorder is still greatly underdiagnosed in both adults and children. In this review, we provide an update on the factors and clinical settings that predispose to Wernicke's encephalopathy, and discuss the most recent insights into epidemiology, pathophysiology, genetics, diagnosis, and treatment. To facilitate the diagnosis, we classify the common and rare symptoms at presentation and the late-stage symptoms. We emphasise the optimum dose of parenteral thiamine required for prophylaxis and treatment of Wernicke's encephalopathy and prevention of Korsakoff's syndrome associated with alcohol misuse. A systematic approach helps to ensure that patients receive a prompt diagnosis and adequate treatment.