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Background: The NFAT family transcription factors play crucial roles in T cell functions. Recently, NFAT has been implicated in the production of an inflammatory cytokine, IL-17A; however, functional differences among NFAT members in IL-17A synthesis have not been elucidated. In this study, the relative contribution of NFAT1 and NFAT2 to IL-17A expression in human T cells was investigated. Methods: NFAT1 and NFAT2 were introduced in human cord blood CD4+ T cells by a lentiviral transduction system. Then, the expression of IL-17A mRNA was determined by quantitative real-time RT-PCR. The transient effects of NFAT1 and NFAT2 on IL-17A expression in Jurkat-Tag cells were also investigated. Results: Stimulation-induced expression of IL-17A in human CD4+ T cells was augmented by the introduction of NFAT1 and more vigorously, NFAT2. IL-17A expression in Jurkat-Tag cells was also enhanced by NFAT1, whereas it was not affected by NFAT2. Conclusion: NFAT1 and NFAT2 facilitated IL-17A expression in human T cells, though distinct mechanisms might be involved in these effects. Copyright © 2012 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

Background: Lacrimal gland enlargement (LGE) is one of the characteristics of Mikulicz's disease (MD). Recently, marked serum immunoglobulin (Ig)G4 elevation and infiltration of IgG4-positive plasma cells in the enlarged exocrine glands have been reported in MD patients. Moreover, we have reported that in patients with LGE and elevated serum IgG4 levels (IgG4-related LGE), T helper type 2 (Th2) cell-mediated immune responses are enhanced. Although prostaglandin D2 (PGD2) and its receptor CRTH2 (chemoattractant receptor-homologous molecule expressed on Th2 cells) have been shown to be involved in Th2 cell-related diseases such as bronchial asthma, their roles in IgG4-related diseases remain unknown. Aim: The aim of this study is to address the role of CD4+ T cells expressing CRTH2 (CRTH2+ CD4+ T cells) in IgG4-related LGE. Methods: We examined the expression of CCR4, CXCR3 and CRTH2 on peripheral blood CD4+ T cells in patients with IgG4-related LGE, in patients with bronchial asthma and in healthy controls. Results: The ratio of CCR4+ to CXCR3+ in CD45RO+ CD4+ T cells was increased in patients with IgG4-related LGE when compared to that in healthy controls, confirming that Th2 cells are predominant in patients with IgG4-related LGE. In addition, the frequency of CRTH2+ cells in CD4+ T cells was significantly increased in these patients, compared to healthy controls. Furthermore, although not statistically significant, the frequency of CRTH2+ cells in CD4+ T cells tended to correlate with the levels of serum IgE and the number of blood eosinophils in patients with IgG4-related LGE. Conclusion: CRTH2+ CD4+ T cells may be involved in the pathogenesis of IgG4-related LGE. Copyright © 2012 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

Background: Evans syndrome (ES) is a rare disorder characterized by combined autoimmune thrombocytopenia and autoimmune hemolytic anemia. Several studies have documented a number of B cell defects, whereas only limited information is currently available about the T cell subset. Methods: A wide panel of immunological analyses aiming specifically at a quantitative and qualitative evaluation of the T cell compartment was performed in an unusual case of ES. The peripheral distribution of the T cell subsets, the diversity of the T cell receptor (TCR) repertoires, the cytokine profile and the T cell apoptosis have been longitudinally evaluated. Results: On first investigation, flow-cytometric immunophenotyping showed a remarkable alteration of T cell homeostasis with deeply reduced CD4+ naive T cells and recent thymic emigrants. This was seen in association with increased levels of T cell activation and apoptosis. Consistently with these data the cytokine profile was characterized by high interferon-γ and low interleukin-2 levels. Staining for CD4 and CD25 molecules showed decreased percentages of circulating regulatory T cells according to the autoimmune nature of ES. Finally, restricted TCR repertoires were demonstrated by a skewed TCR β chain variable (TCRBV) gene usage as well as oligoclonal third complementarity- determining region (CDR3) profiles. A deterioration of the above-mentioned parameters and a worsening of the clinical condition were observed during the follow-up requiring more intensive treatments. Conclusion: The demonstration of multiple T cell defects, in addition to providing pathogenetic information, is likely to alter both acute treatment and outcome of ES. Copyright © 2007 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

Background: Previously reported increased lymphocyte proliferative responses in cow’s milk allergy (CMA) may have been influenced by the lipopolysaccharides (LPS) which contaminate most commercial cow’s milk protein (CMPs). Moreover, peripheral blood mononuclear cells (PBMC) contain both B cells, CD45RA+ naïve T cells, CD25+ regulatory T cells (Tregs) in addition to antigen-specific CD45RA– memory T cells. Methods: PBMC from clinically reactive and tolerised patients with IgE- and non-IgE-mediated CMA were depleted of CD45RA+ T cells and putative CD25+ Tregs. The proliferative index to LPS-depleted α-, β- and κ-casein and β-lactoglobulin was compared in the memory T-cell-enriched, Treg-depleted PBMC and in bulk PBMC. Results: Clinically reactive IgE-mediated CMA patients had increased responses to caseins only. Tolerised patients, particularly those with atopic dermatitis, had decreased responses to κ-casein which were restored after Treg depletion. Interleukin-4 and interferon-γ were generally not detected in the culture supernatants. No differences were seen between reactive and tolerant delayed non-IgE-mediated CMA patients. Conclusions: Proliferative responses to α-, β- and κ-caseins (but not β-lactoglobulin) were observed in clinically reactive IgE-mediated CMA patients only. A markedly decreased proliferative response to κ-casein in tolerised IgE-mediated CMA patients with atopic dermatitis, which was abrogated by Treg depletion, suggested a role for κ-casein in tolerance induction. Non-IgE-mediated CMA patients had no increased proliferative response to any milk proteins. Copyright © 2007 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

Background: Previously reported increased lymphocyte proliferative responses in cow’s milk allergy (CMA) may have been influenced by the lipopolysaccharides (LPS) which contaminate most commercial cow’s milk protein (CMPs). Moreover, peripheral blood mononuclear cells (PBMC) contain both B cells, CD45RA+ naïve T cells, CD25+ regulatory T cells (Tregs) in addition to antigen-specific CD45RA– memory T cells. Methods: PBMC from clinically reactive and tolerised patients with IgE- and non-IgE-mediated CMA were depleted of CD45RA+ T cells and putative CD25+ Tregs. The proliferative index to LPS-depleted α-, β- and κ-casein and β-lactoglobulin was compared in the memory T-cell-enriched, Treg-depleted PBMC and in bulk PBMC. Results: Clinically reactive IgE-mediated CMA patients had increased responses to caseins only. Tolerised patients, particularly those with atopic dermatitis, had decreased responses to κ-casein which were restored after Treg depletion. Interleukin-4 and interferon-γ were generally not detected in the culture supernatants. No differences were seen between reactive and tolerant delayed non-IgE-mediated CMA patients. Conclusions: Proliferative responses to α-, β- and κ-caseins (but not β-lactoglobulin) were observed in clinically reactive IgE-mediated CMA patients only. A markedly decreased proliferative response to κ-casein in tolerised IgE-mediated CMA patients with atopic dermatitis, which was abrogated by Treg depletion, suggested a role for κ-casein in tolerance induction. Non-IgE-mediated CMA patients had no increased proliferative response to any milk proteins. Copyright © 2007 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

Background: Limiting allergen exposure in the sensitization phase has been proposed as a means of primary prevention of asthma, but its effectiveness is debated. Hypothesis: Primary prevention of asthma is more effective in limiting asthma symptoms in young guinea pigs compared with adults, whether males or females. Methods: The following experimental groups were used: young/young, sensitized and challenged before sexual maturity; young/adult, sensitized young and challenged after sexual maturity; adult/adult, sensitized and challenged after sexual maturity. Males and females were sensitized intraperitoneally with varying doses of ovalbumin (OVA) and challenged intratracheally with a constant OVA dose. Cellular infiltration into lung and lavage fluid as well as airway hyperresponsiveness to intravenous methacholine was determined 24 h later. Results: In unsensitized animals, density of resident inflammatory cells as well as baseline pulmonary function differed with age and sex. Maximum OVA-induced eosinophilia in females occurred at a lower sensitizing dose of OVA than in males, and the slopes of the dose-response relationship differed significantly between sexes. Young females had more pronounced increases in eosinophils compared with some adult treatment groups. The concentrations of OVA-specific antibodies were not directly related to differences in cellular infiltration. Airway hyperresponsiveness to methacholine challenge was observed in all treatment groups. Conclusion: Young animals require major reductions in allergen exposure compared with adults to effectively limit airway inflammation in primary prevention. Heterogeneity of asthma symptoms seen with age and sex suggests that primary prevention by limiting allergen exposure or treatment with anti-inflammatory or bronchodilator drugs may be more effective strategies for specific age and gender populations. Copyright © 2006 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

Background: Mast cells are key effector cells in the early-phase allergic inflammation and in diverse immunological and pathological processes. Sopoongsan (SPS), a traditional Korean medicine, has been used as therapeutics for allergic diseases such as atopic dermatitis (AD). The precise effect in experimental models of SPS, how-ever, remains unknown. In this report, we investigated the effect of SPS on mast cell-mediated anaphylactic reactions and cytokine production in in vivo and in vitro murine models. Methods: Compound 48/80-induced histamine and ear swelling were measured with the various concentrations of SPS. The amount of dye was determined colorimetrically after antidinitrophenyl IgE antibody-induced passive cutaneous anaphylaxis reaction. Secretion of tumor necrosis factor-α (TNF-α), interleukin-8 (IL-8) and IL-6 in supernatants from HMC-1 cells was measured by a sandwich enzyme-linked immunosorbent assay. The expression level of nuclearfactor (NF)-κB/Rel A in the nucleus and the activation of mitogen-activated protein kinases (MAPKs) were examined by Western blot analysis. Results: SPS inhibited the degranulation and histamine release from the rat peritoneal mast cells activated by compound 48/80. Compound 48/80-induced ear swelling was significantly reduced. SPS also showed an inhibitory effect of passive cutaneous anaphylaxis reaction. Significantly reduced levels (p < 0.05) of TNF-α, IL-8 and IL-6 were observed in the human mast cell line with SPS and SPS components. In addition, SPS inhibited an increase of NF-κB and extracellular signal-regulated kinase ½ activity. Conclusions: These findings suggest that SPS has an inhibitory effect on atopic allergic reaction and this might be useful for the clinical application to treat allergic diseases such as AD. [ABSTRACT FROM AUTHOR]

Background: Recently, recombinant hypoallergenic derivatives of the major birch pollen allergen, Bet v 1, were used to treat birch-pollen-allergic patients in a double-blind, placebo-controlled, multi-centre immunotherapy study. The aim of this study was to evaluate the effects of vaccination with aluminium-hydroxide-adsorbed recombinant Bet v 1 derivatives versus placebo on T-cell, cytokine and antibody responses in a subgroup of patients. Methods: Blood was drawn from patients of the Swedish centre (n = 27; rBet v 1 fragments: n = 10; rBet v 1 trimer: n = 8, and placebo-aluminium hydroxide: n = 9) before the start and after completion of the treatment. PBMC were stimulated with rBet v 1 and analysed for cytokine (IL-4, IL-5, IL-10, IL-12, IL-13 and IFN-γ)-secreting cells by ELISpot. Bet v 1-specific antibody levels in serum (IgG1–4, IgE and IgA) were measured by ELISA. Skin prick tests with defined Bet v 1 concentrations were performed before and 10–11 months after the beginning of the study. Results: Bet v 1-specific IgG levels, consisting of IgG1, IgG2 and IgG4, were significantly increased after treatment with recombinant allergen derivatives. Treatment with rBet v 1 trimer led to a significant (p < 0.05) reduction of Bet v 1-reactive IL-5- and IL-13-producing cells, reflecting a reduced Th2 response. In addition, a decreased number of Bet v 1-reactive IL-4 producing (p = 0.07) and an increase of IL-12-producing (p = 0.06) cells was noted in the trimer-treated patients. In contrast to placebo, active treatment resulted in significantly reduced immediate-type skin reactions to Bet v 1 even 10–11 months after treatment. Conclusion: Vaccination with recombinant hypoallergenic Bet v 1 derivatives induces a Bet v 1-specific IgG response and leads to reduced skin reactivity in allergic patients. A reduction of Bet v 1-specific Th2 responses was observed in trimer-treated patients, which may reflect the intrinsic property of this allergen derivative. Copyright © 2005 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

Anergy, tolerance and active suppression may not be independent events, but rather involve similar mechanisms and cell types in immune regulation. Induction of allergen-specific regulatory/suppressor T cells (TReg) seems essential for the maintenance of a healthy immune response to allergens. Allergen-specific immunotherapy can induce specific TReg cells that abolish allergen-induced proliferation of T helper 1 (Th1) and Th2 cells, as well as their cytokine production. TReg cells utilize multiple suppressive mechanisms, interleukin-10 (IL-10) and transforming growth factor-β (TGF-β) as secreted cytokines and CTLA-4, PD-1, mTGF-β, mIL-10, TGF-βR and IL-10R as surface molecules. An important aspect of TReg cells is the regulation of antibody isotypes and suppression of proinflammatory cells. IL-10 and TGF-β secreted by TReg cells skew production of IgE towards the noninflammatory isotypes, IgG4 and IgA, respectively. Furthermore, TReg cells may directly or indirectly suppress effector cells of allergic inflammation such as basophils and eosinophils. In conclusion, induction of antigen-specific TReg cells may redirect an inappropriate immune response against allergen or autoantigens with the help of a broad range of suppressor mechanisms. Copyright © 2004 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

The development of new blood vessels, i.e. angiogenesis, is a rate-limiting step in the development of tumors since tumor growth is generally limited to 1–2 mm3 in the absence of a blood supply. Thus, the inhibition of tumor growth by attacking the tumor’s vascular supply offers a primary target for antiangiogenic intervention by DNA-based vaccines. Here, we describe two novel orally delivered DNA vaccines which suppress tumor angiogenesis and induce a robust cell-mediated immune response that provides for long-lived protection against melanoma, colon, breast and non-small-cell lung carcinoma in mouse model systems. These vaccines, which are delivered by attenuated Salmonella typhimurium to secondary lymphoid organs, are directed against such targets as vascular endothelial growth factor receptor 2 (FLK-1) and transcription factor Fos-related antigen 1 (Fra-1). Both vaccines break peripheral T cell tolerance against these self-antigens and induce a robust T cell-mediated immune response leading to suppression of tumor angiogenesis and resulting in effective suppression of tumor growth and metastases. Such research efforts may open up new possibilities for the rational design of future DNA vaccines effective for the prevention and treatment of cancer. Copyright © 2004 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

Background: The aim of this study was to analyze cellular and cytokine interactions governing the development of synovial tissue outgrowth in patients with rheumatoid arthritis (RA). Methods: A single–cell suspension of dissociated synovial tissues of RA patients was cultured for a long period to develop tissue outgrowth. The resulting tissue outgrowth was characterized by immunohistochemical staining and ELISA. Results: The tissue outgrowth developed in vitro included various cell types, such as macrophage–like synovial cells, fibroblast–like synovial cells and lymphocytes. Even after prolonged cultivation, synovial cells devoid of infiltrating T lymphocytes did not form tissue outgrowth. The outgrowth contained CD3+ cells, LeuM3 (CD14)+ cells and HLA–DR+ cells. The T cells expressed lymphocyte function–associated antigen (LFA)–1 and CD2, and the synovial cells expressed intracellular adhesion molecule (ICAM)–1 and LFA–3, suggesting possible interactions via LFA–1/ICAM–1 and CD2/LFA–3. Production of T–cell derived IFN–γ and IL–17 and synovial–cell–derived fibroblast growth factor (FGF)–1 and IL–15 was confirmed in the tissue outgrowth as well as in RA synovial tissue. These cell types stimulate each other by secreting cytokines, leading to the secretion of proinflammatory cytokines and matrix metalloproteinase (MMP)–1 by the tissue outgrowth and proliferation of both lymphocytes and synovial cells. Conclusion: This study emphasizes the importance of cellular interactions between T cells and synovial cells, via adhesion molecules and the secretion of cytokines with stimulatory activity towards other cell types, for the hyperactivity of RA synovial cells. [ABSTRACT FROM AUTHOR]

The aim of this study was to compare the effects of IL–4, IL–12 and IFN–γ on the production of T helper–1 (Th1) and T helper–2 (Th2)–type cytokines from human peripheral blood 'naive' CD45RA and 'memory' CD45RO CD4 T cells. CD45RA or CD45RO CD4 T cells were cultured for 4 days with phorbol myristate acetate (PMA) and ionomycin and either IL–4, IFN–γ or IL–12 and their ability to proliferate and secrete IFN–γ and IL–4 determined. Purified CD45RO CD4 T cells stimulated with PMA and ionomycin secreted higher levels of IL–4 and IFN–γ, as measured by ELISA, than CD45RA CD4 T cells which secreted little IL–4 or IFN–γ. However, CD45RA and CD45RO CD4 T cells proliferated to the same extent and IL–4, IFN–γ and IL–12 had no effect on this. IL–12 and IFN–γ had no effect on the amount of IL–4 secreted by PMA and ionomycin–stimulated CD45RO CD4 T cells, but culture with IL–4 enhanced IL–4 production 7–fold. IL–12 increased the amount of IFN–γ produced by CD45RO CD4 T cells 2– to 3–fold. Small amounts of IFN–γ production were induced in CD4 CD45RA T cells by IL–12 and IFN–γ. These results indicate: (1) that CD45RA cells cannot make significant amounts of IL–4 under the conditions used, (2) that CD45RO cells can produce both Th1 and Th2 cytokines immediately upon restimulation, (3) that IL–12 favours Th1 cytokine production in both CD45RA and CD45RO CD4 T cells, and (4) that IFN–γ favours IFN–γ production in CD45RA but not CD45RO cells. [ABSTRACT FROM AUTHOR]

In this study we first investigated the cellular immune responses in mice with chronic liver injury induced by delayed-type hypersensitivity to picryl chloride (PCl). A continuous reduction, after week 3 of liver injury, was observed in the level of PCl-induced contact sensitivity but not in sheep red blood cell-induced footpad reaction, suggesting the presence of PCl-specific suppression. When spleen cells from mice whose liver had been injured for 1 week were systemically transferred into syngeneic recipients with the liver injury, the elevation in serum lactic dehydrogenase and the decrease in alkaline phosphatase and albumin levels in recipient mice were significantly exacerbated. However, when the liver damage in the donor mouse was allowed to proceed for 3, 5 or 7 weeks, biochemical changes in recipients were reduced to near normal levels. A flow-cytometric assay demonstrated that the number of CD4+ T cells in both spleen cells and liver nonparenchymal cells decreased dramatically during the late phase of liver injury, while CD8+ counts did not. These findings suggest that CD4+ and CD8+ T lymphocytes may contribute to the positive and negative regulation, respectively, of the early and late phases in the chronic development of liver injury. [ABSTRACT FROM AUTHOR]