The incorporation of RANTES or IL-23 into DNA vaccines may improve their immunogenicity by the recruitment and activation of dendritic cells. This may also select for a TH1 response counteracting the TH2 response which can predominate when a DNA vaccine is delivered by gene gun. We have immunized mice with various DNA constructs encoding APR/8/34 influenza virus hemagglutinin (HA), either fused to or separate from, IL-23 or RANTES using a gene gun. Those immunized with IL-23/HA fusion constructs and challenged with influenza 27 weeks post-vaccination, tended to h...

Bis-8-hydroxyquinoline substituted benzylamines have been synthesized and screened for their antitumor activity on KB3 cell line model. Synthesis of this series of new analogues was accomplished using a one pot specific methodology which allows the synthesis of both bis- and mono-8-hydroxyquinoline substituted benzylamines. Among the synthesized compounds two compounds (4a and 5a), respectively, named JLK 1472 and JLK 1486, were particularly potent on KB3 cell line. Their CC(50) values being, respectively, 2.6 and 1.3 nM. Screened on a panel of cell lines showing...

The importance of conventional dendritic cells (cDCs) in the processing and presentation of antigen is well established, but the contribution of plasmacytoid dendritic cells (pDCs) to these processes, and hence to T cell immunity, remains unclear. Here we showed that unlike cDCs, pDCs continued to synthesize major histocompatibility complex (MHC) class II molecules and the MHC class II ubiquitin ligase MARCH1 long after activation. Sustained MHC class II-peptide complex formation, ubiquitination and turnover rendered pDCs inefficient in the presentation of exogen...

The development of functionally specialized subtypes of dendritic cells (DCs) can be modeled through the culture of bone marrow with the ligand for the cytokine receptor Flt3. Such cultures produce DCs resembling spleen plasmacytoid DCs (pDCs), CD8(+) conventional DCs (cDCs) and CD8(-) cDCs. Here we isolated two sequential DC-committed precursor cells from such cultures: dividing 'pro-DCs', which gave rise to transitional 'pre-DCs' en route to differentiating into the three distinct DC subtypes (pDCs, CD8(+) cDCs and CD8(-) cDCs). We also isolated an in vivo equi...

OBJECTIVES: Recent laboratory and clinical data suggest that two prototype autoimmune diseases, systemic lupus erythematosus and rheumatoid arthritis are mainly driven by distinct cytokines, interferon (IFN)-alpha and tumour necrosis factor (TNF)-alpha, respectively. We here investigated the presence and characteristics of natural type I IFN-producing cells (IPCs), as well as IFN-alpha and TNF-alpha expression at sites of inflammation in juvenile idiopathic arthritis (JIA). METHODS: Peripheral blood (PB) and synovial fluid (SF) mononuclear cells (MNCs) (n = 25 ea...

The direct assessment of T helper (T(H))-cell responses specific for antigens is essential to evaluate pathogenic and protective immunity. Presently, analysis and isolation of antigen-specific T(H) cells is restricted to cells that produce cytokines, or can be performed only with a rare selection of specific peptide major histocompatibility complex class II (MHC II) multimers. Here we report a new method that enables the assessment and isolation of T(H) cells specific for a defined antigen according to CD154 expression induced after stimulation in vitro. We show ...

Abstract Background Clinical studies require protocols where a sufficient number of well-characterized highly immunogenic DC are produced according to good manufacturing practice (GMP) guidelines. Methods In the present study, using leukapheresis products from 10 cancer patients, we validated an elutriation technology for large-scale clinical grade production of monocyte-derived DC. Results The elutriation method gave a very high purity (mean±SD) (86±5.3%) and recovery (66±10.4%) of monocytes. Specifically for the two monocyte-rich fractions (3 and 4,) th...

Activation of a cytotoxic T lymphocyte (CTL) response in an antigen-exposed lymph node involves a great diversity of encounters between naive CTL and APC that differ in both duration and quality. This broad spectrum of priming events instigates a complex blend of CTL developmental pathways. Using an experimental system that allows tight control over CTL priming, we have singled out defined priming events and analyzed the impact of the resulting instructional program on the effector and memory phases of the CTL response. As expected, prolonged antigenic stimulatio...

BACKGROUND: Tumour necrosis factor alpha (TNFalpha) therapy is a promising anti-cancer treatment when combined with radiotherapy due to its potent radio sensitising effects, but systemic toxicity has limited its clinical use. Previously, non-replicative adenovirus vectors have been used to deliver TNFalpha directly to the tumour, including under the control of a radiation sensitive promoter. Here, we have used an ICP34.5 deleted, oncolytic herpes simplex virus (HSV) for delivery to increase expression levels and spread through the tumour, and the use of the US11 t...

Synthetic peptide vaccines aiming at the induction of a protective CD8(+) T-cell response against infectious or malignant diseases are widely used in the clinic but, despite their success in animal models, they do not yet live up to their promise in humans. This review assesses the development of synthetic peptide vaccines, weighs it against the immunological concepts that have emerged, and identifies the key issues that play a role in the failure or success of a synthetic peptide vaccine. The current state-of-the-art peptide vaccine is a complete synthetic inflam...

Evidence for the existence of CLL-specific antigens recognized by the immune system can be gathered from the observation that many patients display monoclonal or oligoclonal expansions and skewed repertoire of T cells. In vitro functional studies have shown that tumor-specific T-cells are able to lyse the leukemic cells. Antileukemic cellular immunity may be boosted in vivo using dendritic cell-based immunotherapy. Our preclinical studies provide evidence that DC that had endocytosed apoptotic CLL cells (Apo-DC) were superior to fusion hybrids, tumor lysate or RN...

The realization that dendritic cells (DCs) orchestrate innate and adaptive immune responses has stimulated research on harnessing DCs to create more effective vaccines. Early clinical trials exploring autologous DCs that were loaded with antigens ex vivo to induce T-cell responses have provided proof of principle. Here, we discuss how direct targeting of antigens to DC surface receptors in vivo might replace laborious and expensive ex vivo culturing, and facilitate large-scale application of DC-based vaccination therapies.

Since their discovery, there has been significant progress in the understanding of dendritic cell (DC) biology. Their capacity for priming an immune response against pathogens and cancers has been exploited clinically. However, the objective responses obtained to date using DC cancer vaccines have been modest. Suboptimal DC preparations, limited tumor target antigens, and the essential need to initiate trials in immunocompromised patients with advanced disease, have all contributed to limited outcomes. The use of fully activated DCs, loaded with multiple, immunoge...

Dendritic cells (DCs) are professional APCs that have a unique capacity to initiate primary immune responses, including tolerogenic responses. We have genetically engineered bone marrow-derived DCs to express the immunosuppressive cytokine IL-10 and tested the ability of these cells to control experimental asthma. A single intratracheal injection of OVA-pulsed IL-10-transduced DCs (OVA-IL-10-DCs) to naive mice before OVA sensitization and challenge prevented all of the cardinal features of airway allergy, namely, eosinophilic airway inflammation, airway hyperreac...

Tumour immunotherapy has become a treatment modality for cancer, harnessing the immune system to recognize and eradicate tumour cells specifically. It is based on the expression of tumour associated antigens (TAA) by the tumour cells and aims at the induction of TAA-specific effector T cell responses, whilst overruling various mechanisms that can hamper the anti-tumour immune response, e.g. regulatory T cells (Treg). (Re-) activation of effector T cells requires the completion of a carefully orchestrated series of specific steps. Particularly important is the pro...

B and T lymphocytes are the mediators of immunity, but their function is under the control of dendritic cells. Dendritic cells in the periphery capture and process antigens, express lymphocyte co-stimulatory molecules, migrate to lymphoid organs and secrete cytokines to initiate immune responses. They not only activate lymphocytes, they also tolerize T cells to antigens that are innate to the body (self-antigens), thereby minimizing autoimmune reactions. Once a neglected cell type, dendritic cells can now be readily obtained in sufficient quantities to allow mole...

Dendritic cells (DC) are professional antigen-presenting cells that are used in vaccine approaches to cancer. Classically, mature monocyte-derived DC are generated in vitro in the presence of interleukin (IL)-4, granulocyte macrophage-colony stimulating factor, and inflammatory cytokines (G4-DC). Recently, it has been described that DC can also be generated in the presence of IL-3 and interferon (IFN)-beta and that these DC are efficiently matured using polyriboinosinic polyribocytidylic acid (I3-DC). In this study, a series of in vitro experiments was performed ...

Dendritic cell (DC) activation is a prerequisite for T cell priming. During infection, activation can ensue from signaling via pattern-recognition receptors after contact with pathogens or infected cells. Alternatively, it has been proposed that DCs can be activated indirectly by signals produced by infected tissues. To address the contribution of tissue-derived signals, we measured DC activation in a model in which radioresistant cells can or cannot respond to lipopolysaccharide (LPS). We report that recognition of LPS by the radioresistant compartment is suffici...

Much effort has been made over the last decade to use dendritic cells (DCs) in vaccines to induce specific antitumor immune responses. However, the great hope provided by in vitro and in vivo preclinical investigations was not translated to the clinic in terms of clinical efficacy. Thus, one of the challenges resides in optimizing DC-based therapy to give maximum clinical efficacy while using manufacturing processes that enable quality control and scale-up of consistent products. In this article, we review DC biology and the DC-based clinical trials performed to ...