Search results for "Lymphocyte activation"
showing 10 items of 414 documents
CD4(+) and CD8(+) anergic T cells induced by interleukin-10-treated human dendritic cells display antigen-specific suppressor activity.
2002
Interleukin-10 (IL-10)–treated dendritic cells (DCs) induce an alloantigen- or peptide-specific anergy in various CD4+ and CD8+ T-cell populations. In the present study, we analyzed whether these anergic T cells are able to regulate antigen-specific immunity. Coculture experiments revealed that alloantigen-specific anergic CD4+ and CD8+ T cells suppressed proliferation of syngeneic T cells in a dose-dependent manner. The same effect was observed when the hemagglutinin-specific CD4+T-cell clone HA1.7 or tyrosinase-specific CD8+ T cells were cocultured with anergic T cells of the same specificity. Anergic T cells did not induce an antigen-independent bystander inhibition. Suppression was depe…
Interleukin 1α Promotes Th1 Differentiation and Inhibits Disease Progression in Leishmania major–susceptible BALB/c Mice
2003
Protective immunity against pathogens such as Leishmania major is mediated by interleukin (IL)-12–dependent Th1-immunity. We have shown previously that skin-dendritic cells (DCs) from both resistant C57BL/6 and susceptible BALB/c mice release IL-12 when infected with L. major, and infected BALB/c DCs effectively vaccinate against leishmaniasis. To determine if cytokines other than IL-12 might influence disease outcome, we surveyed DCs from both strains for production of a variety of cytokines. Skin-DCs produced significantly less IL-1α in response to lipopolysaccharide/interferon γ or L. major when expanded from BALB/c as compared with C57BL/6 mice. In addition, IL-1α mRNA accumulation in l…
Ci8 short, a novel LPS-induced peptide from the ascidian Ciona intestinalis,modulates responses of the human immune system
2017
The selective modulation of immunity is an emerging concept driven by the vast advances in our understanding of this crucial host defense system. Invertebrates have raised researchers’ interest as potential sources of new bioactive molecules owing to their antibacterial, anticancer and immunomodulatory activities. A LipoPolySaccharide (LPS) challenge in the ascidian Ciona intestinalis generates the transcript, Ci8 short, with cisregulatory elements in the 3′ UTR region that are essential for shaping innate immune responses. The derived amino acidic sequence in silico analysis showed specific binding to human Major Histocompatibility Complex (MHC) Class I and Class II alleles. The role of Ci…
Glycoprotein 96-activated dendritic cells induce a CD8-biased T cell response.
2005
Heat shock proteins (Hsps) are able to induce protective immune responses against pathogens and tumors after injection into immunocompetent hosts. The activation of components of the adaptive immune system, including cytotoxic T lymphocytes specific for pathogen- or tumor-derived peptides, is crucial for the establishment of immuno- protection. Hsps acquire these peptides during intracellular protein degradation and when released during necrotic cell death, facilitate their uptake and Minor Histocompatibility Complex (MHC)-restricted representation by professional antigen-presenting cells (APCs). In addition, the interaction of Hsps with APCs, including the Endoplasmatic Reticulum (ER)-resi…
Blue light irradiation suppresses dendritic cells activationin vitro
2013
Blue light is a UV-free irradiation suitable for treating chronic skin inflammation, for example, atopic dermatitis, psoriasis, and hand- and foot eczema. However, a better understanding of the mode of action is still missing. For this reason, we investigated whether dendritic cells (DC) are directly affected by blue light irradiation in vitro. Here, we report that irradiation neither induced apoptosis nor maturation of monocyte-derived and myeloid DC. However, subsequent DC maturation upon LPS/IFNγ stimulation was impaired in a dose-dependent manner as assessed by maturation markers and cytokine release. Moreover, the potential of this DC to induce cytokine secretion from allogeneic CD4 T …
Induction of regulatory T cells by leflunomide in a murine model of contact allergen sensitivity.
2006
Allergic contact dermatitis and contact hypersensitivity (CHS) are characterized by allergen-specific activation of CD8 + and CD4 + T cells and the production of cytokines resulting in an inflammatory response and tissue damage. We show here that the immunosuppressive compound leflunomide ( N -[4-trifluoro-methylphenyl]-5-methylisoxazol-4 carboxamide, HWA 486) (LF) inhibited the contact allergic response induced in mice by epicutaneous application of the haptens dinitrofluorobenzene (DNFB) and oxazolone. The extent of ear swelling remained significantly reduced following repeated challenge with DNFB for up to 18 weeks. LF and DNFB had to be applied simultaneously for inhibition to occur. Th…
Co-activation of naive CD4+ T cells and bone marrow-derived mast cells results in the development of Th2 cells
1995
Activation of naive dense CD4+ T cells by plate-bound anti-CD3 antibodies favors the development of Th1 cells which, upon re-stimulation, produce significant amounts of IFN-gamma but no IL-4. However, co-activation of such naive T cells in the presence of IgE [anti-dinitrophenyl (DNP)]-loaded bone marrow-derived mast cells (BMMC) on plates coated with anti-CD3 antibodies and DNP-BSA led to the development of IL-4-producing Th2 cells. The same result could be observed if irradiated (800 rad) BMMC were applied as co-stimulators. Moreover, BMMC could be replaced by the supernatant of IgE-activated BMMC suggesting that a soluble mediator, presumably IL-4, was responsible for this effect. This a…
Potential involvement of IL-9 and Th9 cells in the pathogenesis of rheumatoid arthritis
2015
Objective IL-9 has been shown to be upregulated before the clinical onset of articular disease in RA. The exact role of IL-9 and Th9 cells in RA, however, has not yet been adequately studied. The aim of this study was to evaluate the expression of IL-9 and IL-9-expressing cells in RA patients. Methods IL-9, IL-9R, PU.1, IL-9, thymic stromal lymphopoietin (TSLP), IL-4 and TGF-β expression was assessed by real-time-PCR in the synovial tissues of RA and OA patients. IL-9, IL-9R, IL-4, TSLP and TGF-β were also investigated by immunohistochemistry. Peripheral CD4(+) T cell subsets were studied by flow cytometry analysis before and after incubation with citrullinated peptides. Results IL-9 was ov…
Prospective Study of the Evolution of Blood Lymphoid Immune Parameters during Dacarbazine Chemotherapy in Metastatic and Locally Advanced Melanoma Pa…
2014
BackgroundThe importance of immune responses in the control of melanoma growth is well known. However, the implication of these antitumor immune responses in the efficacy of dacarbazine, a cytotoxic drug classically used in the treatment of melanoma, remains poorly understood in humans.MethodsIn this prospective observational study, we performed an immunomonitoring of eleven metastatic or locally advanced patients treated with dacarbazine as a first line of treatment. We assessed by flow cytometry lymphoid populations and their activation state; we also isolated NK cells to perform in vitro cytotoxicity tests.ResultsWe found that chemotherapy induces lymphopenia and that a significantly hig…
Cellular and humoral immune responses against autoreactive T cells in multiple sclerosis patients after T cell vaccination.
1999
Myelin basic protein (MBP)-reactive T cells may play an important role in the autoimmune pathogenesis of multiple sclerosis (MS). MBP-reactive T cells can be specifically targeted by T cell vaccination, a procedure whereby MS patients are immunized with attenuated autologous MBP reactive T cells. T cell vaccination induces immune responses to the vaccine cells together with a depletion of MBP reactive T cells. Forty-nine MS patients were treated with T cell vaccination in an extended phase I trial to study the safety, immune responses and clinical effects of T cell vaccination. In the present paper the immune responses towards the vaccine cells were characterized. Substantial long-term in v…