concanavalin-a and Dermatitis--Allergic-Contact

An immunosuppressant agent with negligible or acceptable toxicity may provide a better therapeutic strategy for treatment of allergic contact dermatitis. We identified a natural cyclopeptide, roseotoxin B, that effectively suppressed cell proliferation and the production of proinflammatory cytokines in activated T cells but exhibited little naive T-cell toxicity at concentrations of 0.3-1 μmol/L. In addition, roseotoxin B inhibited the activation of AKT and signal transducer and activator of transcription-3, suppressed cell cycle-related signaling, caused G0/G1 phase arrest, reduced ribosomal protein-S3 (RPS3)-dependent NF-κB-mediated IL-2 production, and increased autophagy in activated T cells. Furthermore, picryl chloride-induced allergic contact dermatitis was significantly ameliorated by roseotoxin B in mice. The effects of roseotoxin B were inhibited in LC3-knockout mice, indicating that roseotoxin B acts in an autophagy-dependent manner in T-cell-mediated skin diseases. Overall, this study showed a mechanism for roseotoxin B-induced autophagic cell death and provided a unique perspective on autophagy-mediated down-regulation of NF-κB signaling in activated T cells. The unique anti-inflammatory mechanism of roseotoxin B against activated T lymphocytes in allergic contact dermatitis suggests that it could be a potential target for the treatment of immune-related skin diseases.

Topics: Animals; Anti-Inflammatory Agents; Autophagy; Cell Cycle; Cell Proliferation; Concanavalin A; Cytokines; Depsipeptides; Dermatitis, Allergic Contact; Female; Inflammation; Lymphocyte Activation; Mice; Mice, Inbred C57BL; Mice, Knockout; NF-kappa B; Picryl Chloride; Ribosomal Proteins; Signal Transduction; Skin; STAT3 Transcription Factor; T-Lymphocytes

Sceptridium ternatum (ST) is a medicinal herb used in folk remedies for the treatment of various disorders such as pertussis, allergic asthma, abdominalgia, diarrhea, and external use for wound healing. However, the biological and pharmacological activities of ST are not fully clarified besides anti-asthmatic effect.. We studied a Sceptridium ternatum ethanol extract (ST) with respect to its anti-inflammatory and immune regulatory activities in lipopolysaccharide (LPS)-stimulated RAW 264.7 cells, concanavalin A (conA)-stimulated BALB/c mice splenocytes, and a 2,4-dinitrochlorobenzene (DNCB)-induced allergic contact dermatitis (ACD) mouse model.. RAW 264.7 cells were pretreated with ST for 1h and then stimulated with LPS. To determine the anti-inflammatory effects of ST, the production of nitric oxide (NO), interleukin (IL)-1β, IL-6, and tumor necrosis factor-α (TNF-α) were measured using an enzyme-linked immunosorbent assay (ELISA). To determine its anti-allergic effects, splenocytes from BALB/c mice were incubated and stimulated with conA in the absence or presence of ST for 48h. The production of IL-4 and interferon (IFN)-γ in culture supernatants were evaluated by ELISA. To test the effects of ST on ACD, 100μL of 1% DNCB was applied to the dorsal skin of BALB/c mice for 2 weeks, and ST was administered 2 h before DNCB application. The thicknesses of the epidermis and dermis were determined by skin histological analysis. Serum immunoglobulin (Ig) E levels, the production of IL-1β, IL-4, and IL-6 in dorsal skin tissue, and T helper (Th) 2 cytokines production of CD4(+) T cells were analyzed by ELISA. The expression of nuclear transcription factor-κB (NF-κB) both in vitro and in vivo was determined via immunoblotting.. In RAW 264.7 cells, ST inhibited LPS-induced inflammation mediator production and NF-κB expression. ST upregulated IFN-γ production and downregulated IL-4 production in conA-stimulated splenocytes. ST application reduced the thicknesses of the epidermis and dermis by decreasing serum IgE level and the expressions of IL-1β, IL-4, IL-6, and NF-κB in the dorsal skin of the DNCB-induced ACD model mice. Furthermore, ST treated group showed reduction of the Th2 cytokines production in activated CD4(+) T cells.. These findings not only indicate that application of ST reduced skin thickening by regulating Th 2-type allergic responses and inhibiting expression of inflammatory mediators in a DNCB-induced ACD mouse model, but also suggest that Sceptridium ternatum is a natural option for the treatment of skin inflammation.

Topics: Animals; CD4-Positive T-Lymphocytes; Concanavalin A; Cytokines; Dermatitis, Allergic Contact; Dermis; Disease Models, Animal; Epidermis; Female; Hyperplasia; Immunoglobulin E; Interferon-gamma; Interleukin-1; Interleukin-1beta; Interleukin-6; Lipopolysaccharides; Mice; Mice, Inbred BALB C; NF-kappa B; Nitric Oxide; Phytotherapy; Plant Extracts; RAW 264.7 Cells; Spleen; Th2 Cells; Tracheophyta; Tumor Necrosis Factor-alpha

To evaluate the effect of panaxynol (PAN) on delayed type hypersensitivity and possible mechanism.. Allergic contact dermatitis (ACD) was induced by DNCB as a delayed type hypersensitivity (DTH) model to observe effect of PAN on auricle inflammation including pathological injury. Proliferation of T lymphocytes was induced by ConA and measured by MTf method. IFN-gamma secretion of splenocyte induced by ConA was detected by ELISA.. The swelling degree of auricle and pathological injury in ACD mice was reduced significantly by treated with PAN in induction phase. Proliferation of T lymphocytes induced by ConA in vitro was inhibited significantly by PAN, By contrast, no detectable effect was observed in resting splenocyte. IFN-y induced by ConA in splenocytes was inhibited markedly by PAN from 10 micromol x L(-1) and from 6 h.. The results showed that DTH was inhibited by PAN mainly in induction phase and this effect may be related with the inhibition on T lymphocytes proliferation and secretion of IFN-gamma.

Topics: Animals; Cell Proliferation; Concanavalin A; Dermatitis, Allergic Contact; Diynes; Fatty Alcohols; Female; Interferon-gamma; Male; Mice; Mice, Inbred ICR; Spleen; T-Lymphocytes

Previously, we demonstrated the inhibitory effects of Si-Ni-San, a traditional Chinese prescription, on picryl chloride-induced ear contact sensitivity (PCl-CS). This study aimed to evaluate the role of the four major constituents contained in the prescription (saikosaponins, paeoniflorin, naringin and glycyrrhizin) in the inhibitory effect. When administered during the induction phase, saikosaponin a and glycyrrhizin showed significant inhibitory effects, while paeoniflorin and naringin did not. These components in Si-Ni-San also inhibited the activation and proliferation of T lymphocytes as well as the production of cytokines such as tumour necrosis factor-alpha and interferon-gamma to different extents. Saikosaponin a and paeoniflorin dose-dependently reduced the splenocyte adhesion to type I collagen, while glycyrrhizin only showed a slight tendency. Furthermore, treatment with glycyrrhizin or saikosaponin a, rather than paeoniflorin or naringin, moderately inhibited the matrix metalloproteinase (MMP)-2 activity of the splenocytes from PCl-CS mice, and the combination of all four components showed a strong inhibition against MMP-2. Moreover, the components markedly decreased the serum level of nitric oxide in PCl-sensitized mice. The results indicated that saikosaponin a and glycyrrhizin may be the major contributors in the alleviation effect of Si-Ni-San on contact sensitivity, and paeoniflorin and naringin may exhibit a co-operative effect.

Topics: Animals; Benzoates; Bridged-Ring Compounds; Cell Adhesion; Cells, Cultured; Concanavalin A; Dermatitis, Allergic Contact; Dose-Response Relationship, Drug; Drugs, Chinese Herbal; Female; Flavanones; Glucosides; Glycyrrhizic Acid; Immunosuppressive Agents; Interferon-gamma; Lymphocyte Activation; Lymphocytes; Matrix Metalloproteinase 2; Mice; Mice, Inbred BALB C; Mice, Inbred C57BL; Mice, Inbred ICR; Monoterpenes; Nitric Oxide; Oleanolic Acid; Picryl Chloride; RNA, Messenger; Saponins; Spleen

Endocytotic activation of epidermal Langerhans cells (LC) by immunogenic haptens is an early event during development of allergic contact dermatitis. In this work a fast and objective flow-cytometric assay for predictive in vitro testing of contact sensitizers by monitoring their influence on endocytotic mechanisms in murine LC was developed. Epidermal cell suspensions were labelled with a monoclonal antibody directed to MHC class II molecules and pH-sensitive fluorochrome-coupled second-step reagents. For untreated LC a significant quenching of fluorescence intensity by internalization of the MHC-antibody complexes into acidic compartments was noticed. Similar results were obtained in the presence of irritants, the lectin concanavalin A and the phorbol ester phorbol 12-myristate 13-acetate. In contrast stimulation with several well-defined sensitizing compounds resulted in partial conservation of the fluorescence intensity due to the internalization of the labelled complexes into less acidic compartments. Monitoring this modulation of endocytosis is an effective in vitro method to test for properties typical for moderate and strong contact sensitizers. It will help to assess the risk of unknown chemicals to act as haptens and should be useful for restriction of animal experimentation in this field.

Topics: Animals; Concanavalin A; Dermatitis, Allergic Contact; Endocytosis; Female; Flow Cytometry; Fluorescent Dyes; Histocompatibility Antigens Class II; Immunologic Tests; Irritants; Langerhans Cells; Male; Mice; Mice, Inbred BALB C; Phorbol 12,13-Dibutyrate

In order to define the influence of contact allergens on the fluid-phase endocytosis (FPE) of soluble molecules of murine epidermal Langerhans cells (LC), we studied the internalization of FITC-labeled bovine serum albumin (FITC-BSA), TRITC-labeled dextrane (TRITC-DEX) as well as horseradish peroxidase by LC. A 3-parameter flow-cytometric technique was performed for quantification of internalized FITC-BSA in LC using quantum red-labeled reagents for detection of Ia-antigen expression by LC and propidium iodide for exclusion of dead cells from analysis. A temperature-dependent rapid accumulation of FITC-BSA was noticed in time-course studies reaching a plateau between 1 and 2 h of in vitro culture at 37 degrees C. The quantity of FPE under stimulation with phorbol 12-myristate 13-acetate (PMA), concanavalin A (Con A), staphylococcal enterotoxin B (SEB) and contact sensitizers (DNFB, Kathon CG, K2Cr2O7) as well as the irritant SLS was determined. Treatment of LC with PMA and Con A resulted in a significant increase of total FITC-BSA uptake. The contact sensitizers as well as SEB and SLS failed to mediate augmented fluid-phase endocytosis. By use of the pH-insensitive soluble marker, TRITC-DEX and a microscope photometer for evaluation these findings could be confirmed. This excluded any artificial influence of differences in pH values in endocytotic compartments which might have influenced the fluorescence intensity of the pH-sensitive fluorochrome FITC. For qualitative analysis of FPE, the intracellular distribution of internalized horseradish peroxidase in LC was studied. An aggregated pattern became apparent in untreated LC and did not change under stimulation with any of the substances used.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Animals; Carcinogens; Concanavalin A; Dermatitis, Allergic Contact; Dinitrofluorobenzene; Female; Fluorescein-5-isothiocyanate; Langerhans Cells; Male; Mice; Mice, Inbred BALB C; Pinocytosis; Rhodamines; Serum Albumin, Bovine; Tetradecanoylphorbol Acetate