Search results for "Dendritic Cell"

Role of CD1A and HSP60 in the antitumoral response of oesophageal cancer

2011

Oesophageal cancer (OC) is one of the most common and severe forms of tumor. A wider knowledge of molecular mechanisms which lead to a normal epithelium becoming a neoplasm may reveal new strategies to improve treatment and outcome of this disease. In this review, we report recent findings concerning molecular events which take place during carcinogenesis of the oesophagus. In particular, we focus on the role of two molecules, CD1a and Hsp60, which are overexpressed in oesophageal and many other types of tumor. Both molecules may present tumor antigens and promote in situ the stimulation of an antitumoral immune activity. We suggest there is a synergistic action between these molecules. Fur…

Immunity and Aging

2016

In the elderly, many alterations of innate and acquired immunity have been described and viewed as deleterious, hence the term immunosenescence. Immunosenescence is a complex process involving multiple reorganizational and developmentally regulated changes, rather than simple unidirectional decline of complete immune function. On the other hand, some immunological parameters are commonly notably reduced in the elderly, and reciprocally good function is tightly correlated to health status. Whereas innate immunity is relatively well preserved in elderly, acquired immunity is more susceptible due to both the functional decline associated with the passage of time, and to antigen burden to which…

Dendritic cell-based immunotherapy of malignant melanoma: success and limitations.

2007

Dendritic cells (DC) are professional antigen-presenting cells in the immune system which are able to induce primary T-cell responses. Because of their central role in the initiation of immune responses, DC are an important tool for tumor-antigen-specific immunotherapy of cancer. DC vaccination using tumor-antigen-loaded DC has led to tumor regression in individual advanced-stage cancer patients. However, there is a discrepancy between strong and antigen-specific T cell responses in vaccinated cancer patients detectable ex vivo and only weak clinical responses. In most cases the immune system of advanced stage IV cancer patients allows only a temporary anti-tumor response and increasing evi…

Parvovirus H-1-Induced Tumor Cell Death Enhances Human Immune Response In Vitro via Increased Phagocytosis, Maturation, and Cross-Presentation by Den…

2005

Oncotropic and oncolytic viruses have attracted high attention as antitumor agents because they preferentially kill cancer cells in vitro and reduce the incidence of spontaneous, induced, or implanted animal tumors. Some autonomous parvoviruses (H-1, minute virus of mice) and derived recombinant vectors are currently under preclinical evaluation. Still not fully understood, their antitumor properties involve more than just tumor cell killing. Because wild-type parvovirus-mediated tumor cell lysates (TCLs) may trigger antigen-presenting cells (APCs) to augment the host immune repertoire, we analyzed phagocytosis, maturation, and crosspresentation of H-1-induced TCLs by human dendritic cells …

C1q Production by Bone Marrow Stromal Cells

2007

Wheat Amylase Trypsin Inhibitors as Nutritional Activators of Innate Immunity

2015

While the central role of an adaptive, T cell-mediated immune response to certain gluten peptides in celiac disease is well established, the innate immune response to wheat proteins remains less well defined. We identified wheat amylase trypsin inhibitors (ATIs), but not gluten, as major stimulators of innate immune cells (dendritic cells > macrophages > monocytes), while intestinal epithelial cells were nonresponsive. ATIs bind to and activate the CD14-MD2 toll-like receptor 4 (TLR4) complex. This activation occurs both in vitro and in vivo after oral ingestion of purified ATIs or gluten, which is usually enriched in ATIs. Wheat ATIs represent a family of up to 17 proteins with molec…

Neuronal nitric oxide synthase modulates maturation of human dendritic cells.

2010

AbstractDendritic cells (DCs) are the most potent APCs of the immune system. Understanding the intercellular and intracellular signaling processes that lead to DC maturation is critical for determining how these cells initiate T cell-mediated immune processes. NO synthesized by the inducible NO synthase (iNOS) is important for the function of murine DCs. In our study, we investigated the regulation of the arginine/NO-system in human monocyte-derived DCs. Maturation of DCs induced by inflammatory cytokines (IL-1β, TNF, IL-6, and PGE2) resulted in a pronounced expression of neuronal NOS (nNOS) but only minimal levels of iNOS and endothelial NOS were detected in human mature DCs. In addition, …

Phenotype and function of monocyte derived dendritic cells in chronic hepatitis B virus infection.

2004

The antiviral T cell failure of patients with chronic hepatitis B virus (HBV) infection was suggested to be caused by a T cell stimulation defect of dendritic cells (DC). To address this hypothesis, monocyte derived DC (MDDC) of patients with chronic or resolved acute HBV infection and healthy controls were studied phenotypically by FACS analyses and functionally by mixed lymphocyte reaction, ELISA, ELISpot and proliferation assays of MDDC cultures or co-cultures with an allogeneic HBc-specific Th cell clone. HBV infection of MDDC was studied by quantitative PCR. MDDC from HBV patients seemed to be infected by the HBV, showed a reduced surface expression of HLA DR and CD40 and exhibited a r…

Induction of tumor peptide-specific cytotoxic T cells under serum-free conditions by mature human dendritic cells

2000

Tumor vaccination strategies using antigen-pulsed dendritic cells (DC) are currently under development. We established an in vitro system using cultured DC from HLA-typed volunteers for the induction of tumor peptide-specific CD8+ T cells. The strength and specificity of the resulting CTL responses were investigated. For stimulation of syngeneic CD8+ T cells two well-defined DC populations were generated: CD1a+ immature DC cultured in the presence of GM-CSF and IL-4 and mature CD83+ DC generated by additional stimulation with a cytokine cocktail. Stimulations were performed under serum-free conditions and in the absence of exogenous cytokines. Analysis of T cell responses showed that mature…

Immature, but not inactive: the tolerogenic function of immature dendritic cells.

2002

The induction of antigen-specific T cell tolerance and its maintenance in the periphery is critical for the prevention of autoimmunity. Recent evidence shows that dendritic cells (DC) not only initiate T cell responses, but are also involved in silencing of T cell immune responses. The functional activities of DC are mainly dependent on their state of activation and differentiation, that is, terminally differentiated mature DC can efficiently induce the development of T effector cells, whereas immature DC are involved in maintenance of peripheral tolerance. The means by which immature DC maintain peripheral tolerance are not entirely clear, however, their functions include the induction of …