J Dtsch Dermatol Ges
November 2005
Three patients presented with anaphylactic reactions to soy drink. Cross-reactivity of soy protein with birch pollen allergens was identified as the cause for their severe reactions. Because of the rising popularity of soy products and the large number of birch pollen allergic patients, allergologists will be increasingly confronted with these reactions in future.
View Article and Find Full Text PDFTumor-stroma interactions play a decisive role in the growth and metastasis of solid tumors, and involve signalling either by soluble mediators or direct cell-cell interaction. Here, we report the isolation and characterisation of a novel cDNA (MEL4B3), which is induced in cultured dermal fibroblasts exposed to supernatants of melanoma cell lines. MEL4B3 shares high homology with two predicted cDNA sequences for which no activity has so far been described.
View Article and Find Full Text PDFThe expression of the alphavbeta3 integrin (CD51/CD61) on human melanoma cells has been shown to be associated most closely with tumor progression and metastases formation in melanoma. Here, we demonstrated a specific interaction of the alphavbeta3 integrin on melanoma cells with the human Thy-1, an inducible cell adhesion molecule expressed on the cell surface of activated endothelial cells (EC). The interaction was shown by the binding of purified Thy-1 protein to alpha(V)beta(3) transfected cells, to alphavbeta3-expressing melanoma cells and to purified alpha(V)beta(3) integrin.
View Article and Find Full Text PDFOsteopontin (OPN) has been shown to have T helper 1 (Th1) cytokine functions in cell-mediated immunity. Deficiency of OPN is linked to a reduced Th1 immune response in autoimmunity, infectious disease, and delayed-type allergy. Dendritic cells (DCs) are central for the induction of T-cell-mediated immunity, when initially flexible DCs are instructed by priming signals and tissue-derived factors to adopt Th1, Th2, or regulatory T-cell-inducing phenotypes.
View Article and Find Full Text PDFHyperforin, a natural product of St. John's wort (Hypericum perforatum L.), has a number of pharmacological activities, including antidepressive and antibacterial properties.
View Article and Find Full Text PDFThe interplay between dendritic cells (DC) and T cells is a dynamic process critically depending on DC maturation. Ca(2+) influx is one of the initial events occurring during DC/T cell contacts. To determine how DC maturation influences DC/T cell contacts, time-lapse video microscopy was established using TCR-transgenic CD8(+) T cells from P14 mice.
View Article and Find Full Text PDFOne of the unusual properties of chemically reactive haptens is their capacity to simultaneously generate immunogenic determinants for hapten-specific CD8(+) and CD4(+) T cells. Surprisingly, however, a clear dominance of CD8(+) effector T cells is observed in murine contact hypersensitivity to various haptens and upon T cell priming with hapten-modified APCs in vitro. In this study we show that trinitrophenyl-specific CD8(+) T cells actively prevent CD4(+) T cell priming in vitro.
View Article and Find Full Text PDFUVB radiation has been shown to induce T cell tolerance most likely via modulation of the function of antigen-presenting cells like dendritic cells (DC), which are therefore of interest for vaccination therapy. Since little is known about the effects of UVB-irradiated dendritic cells (UVB-DC) on CD8(+) T cells, which are the dominant effectors in various allergic and autoimmune diseases, we have investigated the potential of low dose UVB (100-200 J per m(2)) irradiated bone marrow-derived dendritic cells to induce tolerance in murine CD8(+) T cells specific for the contact allergen trinitrophenyl (TNP) or for a viral peptide. In contrast to the previously reported successful tolerization of primed CD4(+) Th1 cells, neither naïve CD8(+) T cells nor CD8(+) Tc1 effector cells or established CD8(+) T cell clones could be tolerized by TNP-modified or peptide-pulsed UVB-DC in vitro or in vivo.
View Article and Find Full Text PDFTissues must quickly recognize injury to respond to the rapid pace of microbial growth. In skin, dermal microvascular endothelial cells must also react to danger signals from the surrounding tissue and immediately participate by initiating the wound repair process. Components of the extracellular matrix such as hyaluronan are rapidly broken down into smaller molecular weight oligosaccharides in a wound, and these can activate a variety of biological processes.
View Article and Find Full Text PDFThe effector/memory T cell pool branches in homing subsets selectively trafficking to organs such as gut or skin. Little is known about the critical factors in the generation of skin-homing CD8+ T cells, although they are crucial effectors in skin-restricted immune responses such as contact hypersensitivity and melanoma defense. In this study, we show that intracutaneous, but not i.
View Article and Find Full Text PDFActivated dendritic epidermal Langerhans cells and metastatic tumour cells share many properties. Both cell types can invade the surrounding tissue, enter the lymphatic system and travel to regional lymph nodes. We have recently shown that fragments of the extracellular matrix component hyaluronan, which are typically produced at sites of inflammation, can activate dendritic cells.
View Article and Find Full Text PDFLow dose UVB irradiation of dendritic cells (DC) dose-dependently decreases their allostimulatory capacity and inhibits alloreactive T cell proliferation. The reduction of the stimulatory capacity is not associated with a perturbation of CD28 costimulation. To examine the underlying mechanism, cell cycle analysis of T cells from cocultures with UVB-irradiated DC (UVB-DC) was performed, revealing no cell cycle arrest, but an increased number of apoptotic T cells in sub-G(0) phase.
View Article and Find Full Text PDFBackground: Recent investigations suggest an anti-inflammatory and antibacterial effect of hyperforin, which is a major constituent of Hypericum perforatum L. (Saint John's wort).
Objective: In the present half-side comparison study we assessed the efficacy of a cream containing Hypericum: extract standardised to 1.
For psoriasis therapy, topical derivatives of vitamin D3 represent a versatile option: they can be used either alone or in combination with other agents such as topical corticosteroids. In this two-phase parallel-group study, the naturally occurring vitamin D3 analogue, calcitriol, was compared with the vitamin D analogue calcipotriol in 125 patients with chronic plaque-type psoriasis. The proposed treatment regimen was an initial bitherapy for 2 or 4 weeks, with clobetasol propionate 0.
View Article and Find Full Text PDFCD44 is a multifunctional adhesion molecule that has been shown to be a costimulatory factor for T-cell activation in vitro and in vivo. The aim of the present study was to expand these findings by characterizing the role of CD44 during dendritic cell (DC) antigen presentation to naive, resting T cells. Certain monoclonal antibodies (mAbs) directed against all CD44 isoforms (pan CD44), or against the epitope encoded by the alternatively spliced exon v4 (CD44v4), dose-dependently inhibited the capacity of murine DC to induce proliferation of naive alloreactive T cells.
View Article and Find Full Text PDFChemical haptens induce a variety of allergic immune reactions by induction of hapten-specific T cells. Contact sensitizers such as the hapten trinitrochlorobenzene (TNCB) elicit an allergic response, which is confined to the area of antigen exposure. Despite this localized allergic response, we show here that the trinitrophenyl (TNP)-specific immune response is characterized by a rapid induction of CD8+ Tc1 type cytotoxic effector cells already after a single allergen contact which can be detected in all secondary lymphoid organs tested.
View Article and Find Full Text PDFHypericin from St John's wort (Hypericum perforatum L.) is a photosensitizing agent that may cause a severe photodermatitis when higher amounts of St John's wort are ingested by animals. Although Hypericum extracts are widely used in the treatment of depressive disorders, only a little information on the photosensitizing capacity of St John's wort in humans is available.
View Article and Find Full Text PDFPseudohypericin (PH) and hypericin (H) are photosensitizing plant pigments from Hypericum perforatum. H displays cytotoxic and apoptosis-inducing effects in neoplastic cell lines. Here, we have assessed the phototoxic and apoptosis-inducing capacity of PH compared to H in a cell culture model with human leukemic lymphoma cells (Jurkat).
View Article and Find Full Text PDFHyperforin is a plant derived antibiotic from St. John's wort. Here we describe a novel activity of hyperforin, namely its ability to inhibit the growth of tumour cells by induction of apoptosis.
View Article and Find Full Text PDFLow molecular weight fragmentation products of the polysaccharide of Hyaluronic acid (sHA) produced during inflammation have been shown to be potent activators of immunocompetent cells such as dendritic cells (DCs) and macrophages. Here we report that sHA induces maturation of DCs via the Toll-like receptor (TLR)-4, a receptor complex associated with innate immunity and host defense against bacterial infection. Bone marrow-derived DCs from C3H/HeJ and C57BL/10ScCr mice carrying mutant TLR-4 alleles were nonresponsive to sHA-induced phenotypic and functional maturation.
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