concanavalin-a and Dermatitis--Contact

Artemisinin (Art) is a sesquiterpene trioxane lactone from Artemisia annua L., which has been shown to affect immune responses. However, the underlying mechanism remains elusive. In this study, we examined the anti-inflammatory and immunomodulatory effects of Art in a mouse model of contact hypersensitivity (CHS), a T-cell-mediated cutaneous inflammatory reaction. The data showed that topical administration of Art could suppress CHS response and Con A-induced T cell proliferation effectively. Further experiments indicated that Art induced the generation of regulatory T cells (Tregs) and impaired the phosphorylation of AKT, associated with the up-regulation of p38 MAPK activation. Moreover, Art also exerted a strikingly inhibitory effect on IL-17 production, and diminished the level of IL-6 paralleled with an enhancement of TGF-β, which effects were coupled with a significant reduction of STAT3 activation. These data reveal that Art could effectively block CHS response in mice by inducing the generation of Tregs and suppressing the development of Th17, indicating the potential of Art to be applied as an effective therapeutic agent for treating immune-related diseases.

Topics: Animals; Anti-Inflammatory Agents; Artemisinins; Concanavalin A; Cytokines; Dermatitis, Contact; Dinitrofluorobenzene; Disease Models, Animal; Female; Immunologic Factors; Irritants; Lymph Nodes; Mice; Mice, Inbred BALB C; Mitogens; Organ Size; Phytotherapy; Spleen; T-Lymphocytes, Regulatory; Th17 Cells

In the present study, we aimed to investigate the immunosuppressive activity of jaceosidin, a flavone isolated from Artemisia vestita, on T lymphocytes both in vitro and in vivo, and further explore its potential molecular mechanism. Jaceosidin exerted a significant inhibition on the T cell proliferation and activation induced by concanavalin A (Con A) in a concentration-dependent manner and it also inhibited the secretion of the proinflammatory cytokines such as IL-2, TNF-α and IFN-γ of activated T cells. Further study showed that jaceosidin down-regulated STAT1 activation and T-bet expression in activated T cells. Moreover, in order to investigate the immunosuppressive effect of jaceosidin in vivo, the picryl chloride (PCl)-induced ear contact dermatitis model was performed on BALB/c mice. Jaceosidin significantly ameliorated PCl-induced ear swelling in a dose-dependent manner, which was due to its inhibition of the STAT1/T-bet signaling pathway. In summary, these findings suggest that jaceosidin exerts its immunosuppressive effect both in vitro and in vivo through inhibiting T cell proliferation and activation, which is closely associated with its potent down-regulation of the IFN-γ/STAT1/T-bet signaling pathway.

Topics: Animals; Antigens, CD; Antigens, Differentiation, T-Lymphocyte; Cell Proliferation; Concanavalin A; Cytokines; Dermatitis, Contact; Down-Regulation; Female; Flavonoids; Immunosuppressive Agents; Interferon-gamma; Interleukin-2 Receptor alpha Subunit; Lectins, C-Type; Mice; Mice, Inbred BALB C; Signal Transduction; STAT1 Transcription Factor; T-Box Domain Proteins; T-Lymphocytes; Trinitrobenzenesulfonic Acid

To determine how estrogen exacerbates allergies, the effects of 17beta-estradiol (E2) on lymphocyte proliferation were investigated. BALB/c mice were ovariectomized, administered 3.2 microg E2, and sensitized with 50 microL 4-ethoxymethylene-2-phenyl-2-oxazolin-5-one. After 7 days, their spleens were excised and flow cytometrically analyzed. The CD8(+)CD45RA(-)CCR7(-) cell-to-CD8(+) cell ratio in the spleen was greater in the E2-administered mice than in the controls. Splenocytes were cultured under concanavalin A stimulation, with or without E2. After 4 days, the above ratio was greater in the case of E2-treated splenocytes. E2 increases the number of effector memory CD8(+) lymphocytes during sensitization in contact hypersensitivity.

Topics: Animals; CD8-Positive T-Lymphocytes; Cell Proliferation; Cells, Cultured; Concanavalin A; Dermatitis, Contact; Endocrine Disruptors; Estradiol; Female; Flow Cytometry; Immunologic Memory; Lymphocyte Count; Mice; Mice, Inbred BALB C; Ovariectomy; Spleen

Although reactive oxygen species (ROS) have long been considered to play pathogenic roles in various disorders, this classic view is now being challenged by the recent discovery of their physiological roles in cellular signaling. To determine the immunological consequence of pharmacological disruption of endogenous redox regulation, we used a selenium-containing antioxidant compound ebselen known to modulate both thioredoxin and glutaredoxin pathways. Ebselen at 5-20 micro M inhibited Con A-induced proliferation and cytokine production by the HDK-1 T cell line as well as the LPS-triggered cytokine production by XS52 dendritic cell (DC) line. Working with the in vitro-reconstituted Ag presentation system composed of bone marrow-derived DC, CD4(+) T cells purified from DO11.10 TCR-transgenic mice and OVA peptide (serving as Ag), we observed that 1) both T cells and DC elevate intracellular oxidation states upon Ag-specific interaction; 2) ebselen significantly inhibits ROS production in both populations; and 3) ebselen at 5-20 micro M inhibits DC-induced proliferation and cytokine production by T cells as well as T cell-induced cytokine production by DC. Thus, Ag-specific, bidirectional DC-T cell communication can be blocked by interfering with the redox regulation pathways. Allergic contact hypersensitivity responses in BALB/c mice to oxazolone, but not irritant contact hypersensitivity responses to croton oil, were suppressed significantly by postchallenge treatment with oral administrations of ebselen (100 mg/kg per day). These results provide both conceptual and technical frameworks for studying ROS-dependent regulation of DC-T cell communication during Ag presentation and for testing the potential utility of antioxidants for the treatment of immunological disease.

Topics: Allergens; Animals; Anti-Inflammatory Agents, Non-Steroidal; Antigen Presentation; Azoles; Clone Cells; Concanavalin A; Dendritic Cells; Dermatitis, Contact; Epitopes, T-Lymphocyte; Female; Irritants; Isoindoles; Lipopolysaccharides; Lymphocyte Activation; Mice; Mice, Inbred BALB C; Mice, Transgenic; Organoselenium Compounds; Oxazolone; Reactive Oxygen Species; Th1 Cells

Several studies have demonstrated that dietary nucleotides play a role in maintaining T-cell dependent immunity. In this work, we investigated the effects of nucleotide supplementation of a nucleotide-free diet (NFD) on some immunity parameters in BALB/c mice. Twenty day old mice were maintained on diets for 30 days prior to use in experiments. The addition of nucleotide mixtures to NFD resulted in an increase in the response of hemolytic IgG-forming cells induced by previous immunization with sheep erythrocytes. When NFD was supplemented with single nucleotides, AMP, GMP, or UMP increased the IgG response, whereas CMP and IMP were without effect. GMP was the only nucleotide that increased the hemolytic IgM-forming cell response. Neither the contact hypersensitivity response to dinitrofluorobenzene nor the time of death after transplantation of a syngenic lymphoma was modified by nucleotide addition to NFD. The in vitro proliferative response of splenocytes to LPS was not affected by nucleotide supplementation of NFD, but the ConA-driven proliferative response was increased in mice fed NFD supplemented with nucleotide mixtures or with UMP. These data show that dietary mononucleotides stimulated at least some T-cell dependent immunity mechanisms. Moreover, these stimulatory effects may be obtained by supplementing a nucleotide-free diet with a mixture in which mononucleotides are at the same levels as in murine breast milk.

Topics: Animals; B-Lymphocytes; Cells, Cultured; Concanavalin A; Dermatitis, Contact; Dinitrofluorobenzene; Erythrocytes; Female; Food, Fortified; Immunoglobulin G; Lipopolysaccharides; Lymphocyte Activation; Lymphoma; Mice; Mice, Inbred BALB C; Nucleotides; Sheep; Transplantation, Isogeneic

We investigated the in vivo selective anti-inflammatory effect of L-156,602, which was first identified as a preferential delayed-type hypersensitivity-suppressant in our screening program and first reported to be a C5a antagonist. The agent most profoundly suppressed footpad edema 4 h after elicitation by concanavalin A (con A) and also caused a significantly impaired response after a further 20 h. Footpad edema induced by either serotonin, carrageenan or zymosan was not much influenced by the agent. Although the dominant cell population that migrated in response to con A and zymosan 4 h after elicitation was neutrophils, L-156,602 specifically prevented the con-A-induced migration of neutrophils, suggesting a distinct mechanism of neutrophil recruitment between con A and zymosan-induced inflammation. The agent also reduced the contact-sensitivity response, especially in host mice sensitized with a moderate dose of picryl chloride and almost completely suppressed the infiltration of mononuclear leukocytes and neutrophils into the site of inflammation. These selective effects of L-156,602 on inflammatory reactions appeared to be not merely via C5a antagonism.

Topics: Animals; Anti-Inflammatory Agents, Non-Steroidal; Antibiotics, Antineoplastic; Carrageenan; Complement C5a; Concanavalin A; Dermatitis, Contact; Edema; Female; Hindlimb; Mice; Mice, Inbred DBA; Neutrophils; Peptides, Cyclic; Picryl Chloride; Serotonin; Specific Pathogen-Free Organisms; Zymosan

Lymphocyte transformation tests were performed on peripheral blood taken from individuals with a history of contact dermatitis who also presented with a positive patch test to nickel sulphate, and from individuals with no history of contact dermatitis. The results implied that nickel leached out from metallic orthodontic appliances in sufficient amounts and of a chemical nature adequate to stimulate proliferation of lymphocytes from some of the nickel-sensitive subjects.

Topics: Analysis of Variance; Cells, Cultured; Concanavalin A; Corrosion; Dermatitis, Contact; Humans; Lymphocyte Activation; Nickel; Orthodontic Appliances; Pilot Projects; Spectrophotometry, Atomic; T-Lymphocytes

Primary antibody and cutaneous hypersensitivity responses to BSA revealed differences between two lines of chickens that had been selected during 12 generations for either high (H) or low (L) antibody responses to SRBC. Levels of total and IgM BSA-binding antibodies at Day 8 postsensitization were significantly lower in the L line than in the H line and in a randombred control (C) line that originated from the same parental stock as the selected lines. Both the early and the late classical wing-web responses to BSA were absent in the L line. In contrast, peripheral blood leukocytes from all three lines proliferated equally well in vitro in the presence of BSA. Line by treatment effects were found for mitogen-induced lymphoproliferation in vitro. Peripheral blood leukocytes obtained from BSA-sensitized H line chickens exhibited lower proliferative responses to concanavalin A than peripheral blood leukocytes from C and L line chickens. These results suggest that differences in immune responses in vivo between the present chicken lines are expressed as antibody (-mediated immune) responses to T cell-dependent antigens. The similarity in immune responses to BSA of the H and C lines after 12 generations of divergent selection indicate that selection for an enhanced immune response to one (multiantigenic) antigen (SRBC) may not necessarily implicate improvement of immunity to another antigen (BSA).

Topics: Animals; Antibodies; Chickens; Concanavalin A; Dermatitis, Contact; Erythrocytes; Female; Genotype; Immunity, Cellular; Injections, Subcutaneous; Major Histocompatibility Complex; Selection, Genetic; Serum Albumin, Bovine; Sheep

Propanil is a herbicide that is used extensively in rice farming to kill weeds without damaging the rice plant. The immunotoxic effects of acute exposure to propanil were determined in adult C57Bl/6 female mice exposed intraperitoneally to propanil at doses of 0, 10, 25, 50, 100, 200, or 400 mg/kg body wt. One week following exposure, the immune competency of the animals was assessed. Contact hypersensitivity response (CHR), blastogenic response to T- and B-cell-specific mitogens, and mixed lymphocyte reaction (MLR) were significantly depressed only in propanil-treated animals at 400 mg/kg. However, the number of splenic antibody-producing cells was also significantly depressed in a dose-dependent manner at the lower doses of 50, 100, and 200 mg/kg. In addition, a significant reduction in the thymus weight and an increase in absolute and relative spleen weight were also measured in animals treated with 200 and 400 mg/kg. The increase in spleen weight also showed a concomitant rise in spleen cellularity. These data indicate that propanil has a dose-dependent immunotoxic effect on the adult mouse that affects primarily the humoral response.

Topics: Anilides; Animals; Body Weight; Concanavalin A; Dermatitis, Contact; Female; Immunity; Mice; Mice, Inbred C57BL; Organ Size; Propanil; Spleen

Twenty patients with malignant melanoma were treated with cyclophosphamide (100, 300 or 500 mg/m2 i.v.) in pilot studies to determine whether such treatment affected suppressor-cell activity. Delayed hypersensitivity to dinitrochlorobenzene and other recall antigens, the serological response to primary immunization with pneumococcal or influenza virus antigens, and the serological response to melanoma antigens were found to be normal and were not changed by cyclophosphamide (Cy) treatment. In vitro assays for production of antibodies against sheep red blood cell (SRBC) antigens, reactivity in the mixed lymphocyte culture reaction, and induction of suppressor cells by Concanavalin-A (Con-A) yielded abnormal results as a consequence of increased suppressor-cell activity in eleven, three, and nine patients, but no concordance was seen between results with the three assays prior to treatment. After treatment with Cy, the results of these tests became normal in seven, three, and seven of the patients with previously abnormal results, independent of the dose given. Examining all patients as a group, a statistically significant effect was seen after treatment with Cy on days 14 and 21 in the assay for the production of antibodies against SRBC, and days 7, 14, 21, 28, and 35 in the assay for Con-A-induced suppressor cells. The decrease in suppressor-cell activity was largely restricted to patients who showed increased suppressor-cell activity prior to treatment with Cy. Our results suggest that increased suppressor-cell activity in patients with malignant melanoma does not affect immune reactions generally but is selective, and that the anti-suppressor-cell effect of Cy is restricted to reactions with increased suppressor-cell activity to start. Based on these results, attempts at increasing the immune response to melanoma antigen vaccines administered between 7 and 35 days after treatment with Cy seem justified.

Topics: Antibody Formation; Concanavalin A; Cyclophosphamide; Dermatitis, Contact; Humans; Hypersensitivity, Delayed; Lymphocyte Activation; Lymphocyte Culture Test, Mixed; Melanoma; Phytohemagglutinins; T-Lymphocytes, Regulatory

Peptides derived from fibrinogen, known from earlier studies to inhibit the stimulation of lymphocytes in vitro and to suppress the humoral immune response in vivo, were investigated for their effect on cell-mediated immune reactivity in mice. An unfractioned mixture of peptides with molecular weights under 3,500 injected intraperitoneally at repeated intervals suppressed the contact hypersensitivity to oxazolone but did not influence the skin inflammatory reaction to croton oil. Local injections of peptides had a stronger effect on contact hypersensitivity. Four 200 micrograms local injections of peptides prior to sensitization abolished the increase in lymph node weight and the uptake of 125I-iododeoxyuridine in the draining lymph node after sensitization. Three previously isolated peptides with vasoactive effects inhibited Con A-stimulated incorporation of 3H-thymidine into spleen cells. The first, a pentapeptide (Ala-Arg-Pro-Ala-Lys), and the second, an undecapeptide (Ser-Glu-Leu-Gln-Lys-Val-Pro-Pro-Glu-Trp-Lys) both with an enhancing effect on microvascular permeability, were more potent than the third, a pentapeptide with slight vasoconstrictive properties (Thr-Ser-Glu-Val-Lys). Cell viability was not altered, as measured by trypan blue exclusion and the release of 86Rb. Accumulating evidence indicates that peptides derived from fibrin may be of importance as modulators of cellular immunoreactivity in a number of clinical conditions.

Topics: Animals; Capillary Permeability; Cells, Cultured; Concanavalin A; Dermatitis, Contact; Fibrinogen; Humans; Hypersensitivity, Delayed; Immunity, Cellular; Immunosuppressive Agents; Lymphocytes; Mice; Molecular Weight; Oxazolone; Peptides; Spleen; Thymidine

1-Chloro-2,4-dinitrobenzene (DNCB) contact sensitivity and other T lymphocyte functions were studied in thymectomized and non-thymectomized patients with myasthenia gravis. The ability to develop contact sensitivity was reduced in patients with myasthenia gravis and was further reduced after thymectomy. Memory lymphocyte function, as measured by skin tests with common microbial antigens, was intact. A positive phytohemagglutinin (PHA) skin test was found mainly in those patients who also developed contact sensitivity to DNCB. The number of rosette-forming T cells in the peripheral blood as well as mitogen stimulation with PHA was found to be normal in thymectomized as well as non-thymectomized patients. In the thymectomized group, mitogen stimulation with concanavalin A and staphylococcal protein A was also within the normal range, while increased stimulation was obtained with pokeweed mitogen (PWM) and purified protein derivative (PPD). No alteration in mixed lymphocyte culture reactivity or immunoglobulin levels was obtained compared with healthy blood donors. On the basis of these results, it is concluded that non-thymectomized as well as thymectomized patients with myasthenia gravis may have a defective subpopulation of T cells possibly residing in the TH1-positive population. Furthermore, the increased lymphocyte stimulation obtained with PPD and PWM may indicate a reduction of suppressor cell activity after thymectomy.

Topics: Adolescent; Adult; Aging; Cholinesterase Inhibitors; Concanavalin A; Dermatitis, Contact; Dinitrochlorobenzene; Female; Humans; Male; Middle Aged; Myasthenia Gravis; Phytohemagglutinins; Pokeweed Mitogens; Skin Tests; Staphylococcal Protein A; T-Lymphocytes; Thymectomy; Tuberculin

An in vitro lymphocyte transformation test (LTT) was performed in 8 patients with nickel contact dermatitis and in 4 control persons. The mitogenic response was of the same magnitude before patch testing, after patch testing and after oral challenge with nickel. When purified protein derivative (PPD) was used as the antigen, there was no difference between the LTT response of patients and controls before and after patch testing. After oral challenge with nickel, however, the patients' responses to PPD were significantly increased when compared with the responses after patch testing. The responses of the controls were unchanged. The LTT levels of the patients were approximately the same before and after patch testing, but were markedly increased after oral challenge.

Topics: Administration, Oral; Allergens; Antigens; Concanavalin A; Dermatitis, Contact; Humans; Lymphocyte Activation; Nickel; Patch Tests; Phytohemagglutinins; Pokeweed Mitogens

Patients with psoriasis were found to have less intensive experimental DNCB sensitization and decreased lymphocyte response to nonspecific mitogens, PHA, Con A, and PWM. E rosette formation was defective only in active psoriasis, in contrast to normal T and B cell counts. A reduction in DNCB hypersensitivity development and the percentage of E rosette forming lymphocytes were related to disease activity, but not to extention of skin lesions. The defect of E rosette function appeared to be transitional and completely disappeared in the remission. Abnormalities in CMI in psoriasis were found to be related at least partially to the existence in patients sera of a factor inhibiting normal T lymphocyte function. The study provides no evidence for the presence of primary CMI defect in psoriasis.

Topics: B-Lymphocytes; Concanavalin A; Dermatitis, Contact; Humans; Immunity, Cellular; Immunosuppression Therapy; Leukocyte Count; Psoriasis; Rosette Formation; T-Lymphocytes