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FOXP3 Expression (foxp3 + expression)
Selected AbstractsFOXP3 Expression in Human Kidney Transplant Biopsies Is Associated with Rejection and Time Post Transplant but Not with Favorable OutcomesAMERICAN JOURNAL OF TRANSPLANTATION, Issue 7 2008S. Bunnag Expression of the transcription factor forkhead box P3 (FOXP3) in transplant biopsies is of interest due to its role in a population of regulatory T cells. We analyzed FOXP3 mRNA expression using RT-PCR in 83 renal transplant biopsies for cause in relationship to histopathology, clinical findings and expression of pathogenesis-based transcript sets assessed by microarrays. FOXP3 mRNA was higher in rejection (T-cell and antibody-mediated) than nonrejection. Surprisingly, some native kidney controls also expressed FOXP3 mRNA. Immunostaining for FOXP3 was consistent with RT-PCR, showing interstitial FOXP3+ lymphocytes, even in some native kidney controls. FOXP3 expression correlated with interstitial inflammation, tubulitis, interstitial fibrosis, tubular atrophy, C4d positivity, longer time posttransplant, younger donors, class II panel reactive antibody >20% and transcript sets reflecting inflammation and injury, but unlike these features was time dependent. In multivariate analysis, higher FOXP3 mRNA was independently associated with rejection, T-cell-associated transcripts, younger donor age and longer time posttransplant. FOXP3 expression did not correlate with favorable graft outcomes, even when the analysis was restricted to biopsies with rejection. Thus FOXP3 mRNA expression is a time-dependent feature of inflammatory infiltrates in renal tissue. We hypothesize that time-dependent entry of FOXP3-positive cells represents a mechanism for stabilizing inflammatory sites. [source] Multiple functions of human T cells generated by experimental malaria challengeEUROPEAN JOURNAL OF IMMUNOLOGY, Issue 11 2009Stephen M. Todryk Abstract Protective immunity generated following malaria infection may be comprised of Ab or T cells against malaria Ag of different stages; however, the short-lived immunity that is observed suggests deficiency in immune memory or regulatory activity. In this study, cellular immune responses were investigated in individuals receiving Plasmodium falciparum sporozoite challenge by the natural (mosquito bite) route as part of a malaria vaccine efficacy trial. Parasitemia, monitored by blood film microscopy and PCR, was subsequently cleared with drugs. All individuals demonstrated stable IFN-,, IL-2 and IL-4 ex vivo ELISPOT effector responses against P. falciparum -infected RBC (iRBC) Ag, 28 and 90,days after challenge. However, infected RBC-specific central memory responses, as measured by IFN-, cultured ELISPOT, were low and unstable over time, despite CD4+ T cells being highly proliferative by CFSE dilution, and showed an inverse relationship to parasite density. In support of the observation of poor memory, co-culture experiments showed reduced responses to common recall Ag, indicating malaria-specific regulatory activity. This activity could not be accounted for by the expression of IL-10, TGF-,, FOXP3 or CTLA-4, but proliferating T cells expressed high levels of CD95, indicating a pro-apoptotic phenotype. Lastly, there was an inverse relationship between FOXP3 expression, when measured 10 days after challenge, and ex vivo IFN-, measured more than 100 days later. This study shows that malaria infection elicits specific Th1 and Th2 effector cells, but concomitant weak central memory and regulatory activity, which may help to explain the short-lived immunity observed. [source] Human natural Treg microRNA signature: Role of microRNA-31 and microRNA-21 in FOXP3 expressionEUROPEAN JOURNAL OF IMMUNOLOGY, Issue 6 2009Redouane Rouas Abstract Treg are the main mediators of dominant tolerance. Their mechanisms of action and applications are subjects of considerable debate currently. However, a human microRNA (miR) Treg signature has not been described yet. We investigated human natural Treg and identified a signature composed of five miR (21, 31, 125a, 181c and 374). Among those, two were considerably under-expressed (miR-31 and miR-125a). We identified a functional target sequence for miR-31 in the 3, untranslated region (3, UTR) of FOXP3 mRNA. Using lentiviral transduction of fresh cord blood T cells, we demonstrated that miR-31 and miR-21 had an effect on FOXP3 expression levels. We showed that miR-31 negatively regulates FOXP3 expression by binding directly to its potential target site in the 3, UTR of FOXP3 mRNA. We next demonstrated that miR-21 acted as a positive, though indirect, regulator of FOXP3 expression. Transduction of the remaining three miR had no direct effect on FOXP3 expression or on the phenotype and will remain the subject of future investigations. In conclusion, not only have we identified and validated a miR signature for human natural Treg, but also unveiled some of the mechanisms by which this signature was related to the control of FOXP3 expression in these cells. [source] Loss of FOXP3 expression in natural human CD4+CD25+ regulatory T cells upon repetitive in vitro stimulationEUROPEAN JOURNAL OF IMMUNOLOGY, Issue 4 2009Petra Hoffmann Abstract The adoptive transfer of CD4+CD25+ natural regulatory T cells (Treg) is a promising strategy for the treatment of autoimmune diseases and the prevention of alloresponses after transplantation. Clinical trials exploring this strategy require efficient in vitro expansion of this rare cell population. Protocols developed thus far rely on high-grade purification of Treg prior to culture initiation, a process still hampered by the lack of Treg cell-specific surface markers. Depletion of CD127+ cells was shown to separate activated conventional T cells from natural Treg cell populations allowing the isolation of highly enriched FOXP3+ cells with all functional and molecular characteristics of natural Treg. Here, we demonstrate that upon in vitro expansion, CpG methylation in a conserved region within the FOXP3 gene locus increased in CD4+CD25+CD127low Treg, correlating with loss of FOXP3 expression and emergence of pro-inflammatory cytokines. Further analysis identified CD45RA,FOXP3+ memory-type Treg as the main source of converting cells, whereas CD45RA+FOXP3+ Treg from the same donors showed no conversion within 3,wk of in vitro expansion. Thus, Treg cell lineage differentiation does not seem to represent a final fate decision, as natural Treg can lose their cell-type-specific characteristics after repetitive TCR stimulation. [source] Naturally Occurring Regulatory T cells (CD4+, CD25high, FOXP3+) in the Antrum and Cardia are Associated with Higher H. pylori Colonization and Increased Gene Expression of TGF-,1HELICOBACTER, Issue 4 2008Arne Kandulski Abstract Background:Helicobacter pylori causes gastric inflammation. Despite the induction of H. pylori -specific B- and T cells, the immune response is not sufficient to clear the infection. Regulatory T cells (Treg cells) suppress the activation and proliferation of antigen-specific T cells and mediate immunologic tolerance. FOXP3 was shown to be expressed in a subset of Treg cells known as ,naturally occurring Treg cells'. These cells have not been sufficiently studied in context to H. pylori -induced inflammation in human gastric mucosa. Materials and methods: The study included 76 patients stratified according to the presence of H. pylori. Gene expression levels of FOXP3, transforming growth factor (TGF)-,1, and interleukin-10 were analyzed by quantitative real-time polymerase chain reaction in biopsies from gastric antrum, corpus, and cardia. FOXP3 expression was also analyzed by immunohistochemistry. Differences in expression levels were analyzed by comprehensive statistical analyses and correlated with clinical and histomorphologic parameters. Results:H. pylori -positive patients revealed a 19- to 25-fold induction of FOXP3 transcript levels in antrum and cardia (p < .02). FOXP3 transcript levels correlated positively with inflammation (p < .04) and TGF-,1 transcript levels (p < .001). Furthermore, a positive correlation between FOXP3+ Treg cells and H. pylori colonization was demonstrated. Conclusion: This study demonstrates that H. pylori -induced gastritis is associated with a recruitment of naturally occurring FOXP3+ Treg cells that correlates with the degree of bacterial colonization and mucosal TGF-,1 expression. Together, these data support the hypothesis that naturally FOXP3+ Treg cells play a role in the lifelong persistence of H. pylori infection in humans. [source] Anti tumour necrosis-, therapy increases the number of FOXP3+ regulatory T cells in children affected by Crohn's diseaseIMMUNOLOGY, Issue 2 2008Ida Ricciardelli Summary Crohn's disease (CD) is a chronic inflammatory disease of the gastrointestinal tract. Its pathogenesis is not completely understood, though the prevailing model is that the intestinal flora drives a strong intestinal T helper 1 (Th1)/Th17 type immune response and inflammation in the genetically susceptible host. This leads to overly aggressive T-cell responses to normal bacteria causing tissue damage. Intestinal homeostasis and maintenance of tolerance to harmless antigens in the intestine has been shown to be maintained by CD4+ CD25+ T regulatory cells (Treg) in animal models of inflammatory bowel diseases. Here we investigated whether Infliximab, a chimeric monoclonal antibody directed against tumour necrosis factor (TNF)-, shown to be highly effective in the treatment of CD, has any effect on mucosal CD4+ CD25+ (FOXP3+) Tregs. Colonic mucosal biopsies from children with active Crohn's disease treated in vivo with Infliximab and controls were analysed to determine FOXP3 expression by immunofluorescence and reverse transcription,polymerase chain reaction. We observed that FOXP3+ T cells were significantly reduced in mucosa of CD patients with active disease compared with controls and restored to normal following Infliximab treatment. The frequency of FOXP3+ cells and mRNA expression was significantly increased in CD mucosa from patients treated in vivo with Infliximab compared with CD patients treated with conventional therapies. In conclusion, we show that Infliximab treatment does not solely neutralize soluble TNF-,, but also affects activation and possibly expansion of mucosal regulatory T cells. We suggest that anti TNF-, immunotherapy can also restore mucosal homeostasis in Crohn's disease. [source] Expression and functional characterization of FOXP3+CD4+ regulatory T cells in ulcerative colitis,INFLAMMATORY BOWEL DISEASES, Issue 2 2007Qi T. Yu BS Abstract Background: CD4+CD25+ regulatory T cells (TR) can prevent or treat experimental murine colitis but little is known about their potential role in human inflammatory bowel disease (IBD). FOXP3 is a transcription factor that plays a critical role in the development and function of CD4+CD25+ TR. The aim of this study was to examine the presence and functional characteristics of TR cells in colonic lymphoid tissues in patients with ulcerative colitis (UC). Methods: FOXP3 expression was assessed by flow cytometry, immunohistochemistry, and reverse-transcriptase polymerase chain reaction (RT-PCR). Functional characterization of CD4+CD25+ cells was analyzed by suppression of proliferation and secretion of cytokines by cocultured effector CD4+CD25, T cells. Results: FOXP3+CD4+ T cells are increased in the lamina propria (LP) of inflamed and noninflamed areas of UC colon compared to normal colon. CD4+CD25+ T cells in UC mesenteric lymph nodes (MLN) express FOXP3 mRNA and protein and suppress the proliferation of autologous MLN CD4+CD25, T cells. The suppressor activity of MLN CD4+CD25+ T cells is cell contact-dependent but cytokine-independent. In addition, CD4+CD25+ T cells potently suppress the production of both Th1 (IFN-,, IL-2) and Th2 (IL-5, IL-13) cytokines by cocultured CD4+CD25, T cells. FOXP3+ cells localized in the T-cell-rich areas of MLN and occasionally present in the follicles. Conclusions: There is an expansion of FOXP3+CD4+ T cells in mucosal lymphoid tissues in UC. CD4+CD25+ isolated from UC MLN express FOXP3 and display features of TR cells in spite of active mucosal inflammation. These data suggest that their suppressor activity may be abrogated in vivo or they are unable to counterbalance the chronic mucosal inflammation in UC. (Inflamm Bowel Dis 2007) [source] Maternal allergic disease does not affect the phenotype of T and B cells or the immune response to allergens in neonatesALLERGY, Issue 7 2010E. Rindsjö To cite this article: Rindsjö E, Joerink M, Johansson C, Bremme K, Malmström V, Scheynius A. Maternal allergic disease does not affect the phenotype of T and B cells or the immune response to allergens in neonates. Allergy 2010; 65: 822,830. Abstract Background:, It is hypothesized that the in utero environment in allergic mothers can affect the neonatal immune responses. The aim of this study was to analyse the effect of maternal allergic disease on cord blood mononuclear cell (CBMC) phenotype and proliferative responses upon allergen stimulation. Methods:, Peripheral blood mononuclear cells (PBMC) from 12 allergic and 14 nonallergic mothers and CBMC from their children were analysed. In the mothers, we determined cell proliferation, production of IL-4 and expression of FOXP3 in response to allergen stimulation. In the children, we evaluated cell proliferation and FOXP3 expression following allergen stimulation. Furthermore, expression of different homing markers on T cells and regulatory T cells and maturity of the T cells and B cell subsets were evaluated directly ex vivo. Results:, The timothy- and birch-allergic mothers responded with increased proliferation and/or IL-4 production towards timothy and birch extract, respectively, when compared to nonallergic mothers. This could not be explained by impairment of FOXP3+ regulatory T cells in the allergic mothers. CBMC proliferation and FOXP3 expression in response to allergens were not affected by the allergic status of the mother. Also, phenotype of T cells, FOXP3+ regulatory T cells and B cells was not affected by the allergic status of the mother. Conclusion:, Our results suggest that maternal allergic disease has no effect on the neonatal response to allergens or the phenotype of neonatal lymphocytes. The factors studied here could, however, still affect later development of allergy. [source] Allergen provocation increases TH2-cytokines and FOXP3 expression in the asthmatic lungALLERGY, Issue 3 2010S. Thunberg To cite this article: Thunberg S, Gafvelin G, Nord M, Grönneberg R, Grunewald J, Eklund A, van Hage M. Allergen provocation increases TH2-cytokines and FOXP3 expression in the asthmatic lung. Allergy 2010; 65: 311,318. Abstract Background:, Allergic asthma is caused by allergen-specific IgE and T-helper cell (Th) type 2 responses towards airborne allergens. The objective of this study was to investigate local and systemic regulatory mechanisms in the early asthmatic response to bronchial allergen provocation. Methods:, Birch pollen-allergic patients with mild asthma (n = 13) and healthy nonallergic controls (n = 14) were subjected to bronchoalveolar lavage (BAL) and blood sampling. On patients BAL was performed twice: without preceding provocation (,before samples') and 24 h after bronchial provocation with birch pollen allergen. Lymphocytes in BAL and peripheral blood mononuclear cells (PBMCs) were phenotyped by multi-colour flow cytometry and cytokines measured by cytometric bead array. Proliferation and secreted cytokines were analysed in allergen-stimulated PBMCs, CD25+ depleted PBMCs and PBMCs with IL-10 neutralizing antibodies. Results:, The numbers of CD69+ and FOXP3+ lymphocytes were higher in BAL after compared with before allergen provocation in asthmatic patients. Moreover, allergen provocation increased expression of FOXP3 in CD4+CD25bright cells. The cytokine profile in BAL fluid from asthmatics revealed higher levels of IL-5, compared with the controls, and an increase in IL-5, IL-6, IL-9 and IL-10 after allergen provocation. Pollen allergen stimulated PBMC cultures from asthmatic patients produced elevated levels of IL-5 and IL-13 compared with the controls, which were not affected by depletion of CD25+ cells or IL-10 neutralization. Conclusion:, Despite an increase in CD4+CD25bright cells expressing high levels of FOXP3 in response to bronchial allergen provocation, asthmatic patients exhibit enhanced levels of Th2 cytokines in the lung, which may indicate an inability among infiltrating cells to suppress Th2 responses. [source] Decreased FOXP3 protein expression in patients with asthmaALLERGY, Issue 10 2009S. Provoost Background:, T-regulatory cells (Treg) are important in balancing immune responses and maintaining peripheral tolerance. Current evidence suggests that asthma is characterized by a relative deficiency in Treg, allowing T helper 2 cells to expand. In this study, we aimed to evaluate circulating Treg, defined by the protein FOXP3, in both control subjects and patients with stable asthma. Methods:, Peripheral blood mononuclear cells (PBMC) of control (n = 14) and asthmatic patients (n = 29) were labeled for CD4, CD25, and intracellular FOXP3 and analyzed using flow cytometry. In CD3/CD28 stimulated PBMC, the effects of dexamethasone on the transcription factors T-bet, GATA-3, FOXP3, and RORc2 and representative cytokines were studied. Results:, In control subjects and asthmatic patients, numbers of peripheral blood CD4+CD25high and CD4+CD25highFOXP3+ T-cells were similar. However, FOXP3 protein expression within CD4+CD25high T-cells was significantly decreased in asthmatic patients. There was a tendency for increased FOXP3 expression within CD4+CD25high T-cells in glucocorticosteroid-treated patients when compared to steroid-naive asthmatic patients. In stimulated PBMC, dexamethasone treatment increased the anti-/proinflammatory transcription ratios of FOXP3/GATA-3, FOXP3/T-bet, and FOXP3/RORc2. Conclusion:, Asthmatic patients have decreased FOXP3 protein expression within their CD4+CD25high Treg. Our findings also suggest that treatment with inhaled glucocorticosteroids in asthmatics might increase this FOXP3 protein expression within the CD4+CD25high T-cell population. [source] Clinical outcome and IL-17, IL-23, IL-27 and FOXP3 expression in peripheral blood mononuclear cells of pollen-allergic children during sublingual immunotherapyPEDIATRIC ALLERGY AND IMMUNOLOGY, Issue 1-Part-II 2010Kaisa Nieminen Nieminen K, Valovirta E, Savolainen J. Clinical outcome and IL-17, IL-23, IL-27 and FOXP3 expression in peripheral blood mononuclear cells of pollen-allergic children during sublingual immunotherapy. Pediatr Allergy Immunol 2010: 21: e174,e184. © 2009 John Wiley & Sons A/S Induction of allergen-specific, tolerogenic, IL-10 and/or TGF-,-producing T-regulatory (Treg) cells that express transcription factor FOXP3 is considered as one of the key mechanisms of allergen-specific immunotherapy. However, little is known of the induction of FOXP3 expression in children during sublingual immunotherapy (SLIT). Recently, also, a novel subgroup of T-helper (Th) cells, the Th17 cells, secreting predominantly IL-17 (IL-17A), was identified. The expressions of IL-17 or the Th17-regulating cytokines IL-23 and IL-27 during SLIT are currently completely unexplored. This randomized, placebo-controlled dose-response study was performed to analyze the effects of SLIT on FOXP3, IL-17, IL-23, and IL-27 expressions in peripheral blood mononuclear cells (PBMC) of children with allergic rhinitis and their associations with clinical outcome. Thirty children were included: ten received SLIT with a glycerinated mixture of birch, hazel and alder with a cumulative weekly dose of 24,000 SQ-U, 10 with dose 200,000 SQ-U/wk, and ten received placebo. Cytokine and FOXP3 mRNA expressions in allergen-, purified protein derivative-stimulated and non-stimulated PBMC were determined at 0, 1 and 2 yr of SLIT by real-time RT-PCR (TaqMan®). Symptoms and medications were recorded using diary cards. Allergen-induced IL-17 mRNA expression was significantly increased in the study subjects with elevated combined Symptom Medication Score (SMS) after 2 yr. There was also a significant positive correlation between the allergen-induced IL-17 and SMS in whole study group (r = 0.38, p = 0.039) and especially the 200,000 SQ-U dose-treated group (r = 0.74, p = 0.027) at 2 yr. Allergen-induced FOXP3 mRNA expression was significantly increased in the 200,000 SQ-U dose-treated children after two study years as compared with baseline (p = 0.016) and placebo-treated children (p = 0.028). The changes in FOXP3 mRNA expression positively correlated with IL-10 and TGF-, mRNAs during SLIT in whole study population. Increased allergen-induced IL-17 responses during SLIT are associated with elevated SMS. Increased tolerogenic, allergen-specific Treg responses are also observed in children during SLIT. [source] FOXP3 Expression in Human Kidney Transplant Biopsies Is Associated with Rejection and Time Post Transplant but Not with Favorable OutcomesAMERICAN JOURNAL OF TRANSPLANTATION, Issue 7 2008S. Bunnag Expression of the transcription factor forkhead box P3 (FOXP3) in transplant biopsies is of interest due to its role in a population of regulatory T cells. We analyzed FOXP3 mRNA expression using RT-PCR in 83 renal transplant biopsies for cause in relationship to histopathology, clinical findings and expression of pathogenesis-based transcript sets assessed by microarrays. FOXP3 mRNA was higher in rejection (T-cell and antibody-mediated) than nonrejection. Surprisingly, some native kidney controls also expressed FOXP3 mRNA. Immunostaining for FOXP3 was consistent with RT-PCR, showing interstitial FOXP3+ lymphocytes, even in some native kidney controls. FOXP3 expression correlated with interstitial inflammation, tubulitis, interstitial fibrosis, tubular atrophy, C4d positivity, longer time posttransplant, younger donors, class II panel reactive antibody >20% and transcript sets reflecting inflammation and injury, but unlike these features was time dependent. In multivariate analysis, higher FOXP3 mRNA was independently associated with rejection, T-cell-associated transcripts, younger donor age and longer time posttransplant. FOXP3 expression did not correlate with favorable graft outcomes, even when the analysis was restricted to biopsies with rejection. Thus FOXP3 mRNA expression is a time-dependent feature of inflammatory infiltrates in renal tissue. We hypothesize that time-dependent entry of FOXP3-positive cells represents a mechanism for stabilizing inflammatory sites. [source] Human epithelial ovarian carcinoma cell-derived cytokines cooperatively induce activated CD4+CD25,CD45RA+ naïve T cells to express forkhead box protein 3 and exhibit suppressive ability in vitroCANCER SCIENCE, Issue 11 2009Xiaofeng Zhao Regulatory T cells play an important role in tumor escape from host antitumor immunity. Increased frequencies of CD4+CD25+ regulatory T cells have been documented in the tumor sites, malignant effusions, and peripheral blood of patients with ovarian carcinoma. However, the mechanism involved remains unclear. In the present study, we collected high-purity human CD4+CD25,CD45RA+ naïve T cells by microbead cell separation. These cells did not express FOXP3 by single-cell analysis, and few cells expressed FOXP3 when they were activated with anti-CD3/CD28 dual signal. However, more cells expressed FOXP3 when the supernatant of human epithelial ovarian carcinoma cell culture was added, yet not the supernatant of normal human ovarian surface epithelia cell culture. Neutralization assays revealed that neutralizing antibody against transforming growth factor , (TGF-,), interleukin-10, and interleukin-4 did not abrogate elevated FOXP3 expression induced by carcinoma cell culture supernatant, whereas neutralizing leukemia inhibitory factor (LIF) partially abrogated FOXP3 expression, but LIF alone could not increase FOXP3 expression in activated naïve T cells. Further, an in vitro coculture suppression assay showed that these cells could suppress the proliferation of autologous CD4+CD25,CD45RA, T cells. In summary, our findings show that ovarian carcinoma cells are able to induce expression of FOXP3 and exhibit suppressive ability in activated naïve T cells by producing soluble substances, and multiple cytokines involve in the induction of FOXP3 expression. (Cancer Sci 2009) [source] Validated protocol for FoxP3 reveals increased expression in type 1 diabetes patients,CYTOMETRY, Issue 2 2009Jean Grant Abstract Background FoxP3 has become a key identifier of regulatory T cells. Investigators have used a variety of antibodies and methods for detecting FoxP3 by flow cytometry. To standardize FoxP3 antibody staining for use in clinical trial samples, we tested various antibodies from different vendors, cell preparation protocols and fix/perm reagents, and cell isolation procedures. Using this optimized staining protocol, we evaluated clinical specimens from patients with multiple sclerosis (MS) or type 1 diabetes. Methods FoxP3 antibodies from eBioscience (236A/E7 and PCH101) and BioLegend (206D) were evaluated along with their respective methods and fix/perm reagents for preparation and staining of FoxP3 for flow cytometry. Fresh washed blood and frozen or fresh PBMC were evaluated. Upon optimization of the protocol, clinical samples (frozen PBMC) from patients with MS or type 1 diabetes and healthy control donors were evaluated with the BioLegend antibody. Results Clone 206D from BioLegend yielded optimal staining and the fix/perm reagents from both eBioscience and BioLegend were comparable. Data were also comparable between cells separated by Ficoll (fresh or frozen) and washed blood samples, allowing this protocol to be applicable to different types of samples. We validated this protocol using clinical samples and saw a significant increase in FoxP3 expression in the patients with type 1 diabetes but not in the MS. Conclusions The results from this study will allow the assessment of FoxP3 by flow cytometry on samples from clinical sites that are analyzed in real time on fresh blood or frozen PBMC. © 2008 Clinical Cytometry Society [source] Cell contact interaction between adipose-derived stromal cells and allo-activated T lymphocytesEUROPEAN JOURNAL OF IMMUNOLOGY, Issue 12 2009Monique E. Quaedackers Abstract Mesenchymal stromal cells regulate immune cell function via the secretion of soluble factors. Cell membrane interactions between these cell types may play an additional role. Here, we demonstrate that subpopulations of allo-activated T cells are capable of binding to human adipose-derived stromal cells (ASC). The bound T-cell population contained CD8+ T cells and was enriched for CD4,CD8, T cells, whereas the proportion of CD4+ T cells was decreased compared with the non-bound T-cell population. Bound CD4+ T cells had high proliferative activity and increased CD25 and FoxP3 expression. However, they also expressed CD127, excluding regulatory T-cell function. In CD8+ T cells, IL-2 sensitivity, as determined by the analysis of phosphorylated STAT5, was lower in the presence of ASC and even lower in bound cells. In contrast, IL-2-induced phosphorylated STAT5 levels were higher in bound CD4+ T cells than in non-bound CD4+ T cells. Additionally, pro-proliferative TGF-, signalling via endoglin and SMAD1/5/8 phosphorylation was detected in bound CD4+ T cells. Even after prolonged co-culture with ASC, the activated phenotype of bound CD4+ T cells persisted. In conclusion, these results demonstrate that the binding of lymphocytes to ASC represents an immunomodulatory mechanism in which CD8+ T cells are inhibited in their responsiveness to pro-inflammatory stimuli and reactive CD4+ T cells are depleted from the immune response. [source] T-bet protects against exacerbation of schistosome egg-induced immunopathology by regulating Th17-mediated inflammationEUROPEAN JOURNAL OF IMMUNOLOGY, Issue 9 2009Laura I. Rutitzky Abstract C57BL/6 mice infected with Schistosoma mansoni naturally develop mild CD4+ T-cell-mediated immunopathology characterized by small hepatic granulomas around parasite eggs. However, immunization with soluble egg Ag in CFA markedly exacerbates the lesions by inducing a potent proinflammatory environment with high levels of IFN-, and IL-17, which are signature cytokines of distinct Th1- versus Th17-cell lineages. To determine the relative role of these subsets in disease exacerbation, we examined mice deficient in T-bet (T-bet,/,), which is required for Th1 differentiation and IFN-, production. We now report that immunization with soluble egg Ag in CFA caused a significantly greater enhancement of egg-induced hepatic immunopathology in T-bet,/, mice compared with WT controls, and analysis of their granulomas disclosed a higher proportion of activated DC and CD4+ T cells, as well as a marked influx of neutrophils. The absence of IFN-, in the T-bet,/, mice correlated with a marked increase in IL-23p19, IL-17 and TNF-, in granulomas and MLN. In contrast, T-bet,/, mice had lower levels of IL-4, IL-5 and IL-10 and a reduction in FIZZ1 and FoxP3 expression, suggesting diminished regulatory activity, respectively, by alternatively activated macrophages and Treg. These findings demonstrate that T-bet-dependent signaling negatively regulates Th17-mediated immunopathology in severe schistosomiasis. [source] Estrogen-mediated immunomodulation involves reduced activation of effector T cells, potentiation of treg cells, and enhanced expression of the PD-1 costimulatory pathwayJOURNAL OF NEUROSCIENCE RESEARCH, Issue 2 2006Magdalena J. Polanczyk Abstract Estrogen (E2)-induced immunomodulation involves dual effects on antigen-presenting cells (APC) and CD4+CD25+ regulatory T cells (Treg) but not a direct effect on effector T cells. In this report, we further investigated the effects of E2 on APC and Treg function. We found that E2 treatment in vivo strongly reduced recovery of APC from the peritoneal cavity and inhibited induction of the inflammatory cytokines interleukin (IL)-12 and interferon-, but enhanced secretion of IL-10. Moreover, E2-conditioned bone marrow-derived dendritic cells (BM-DC) could both enhance Treg activity and directly inhibit responder T cells in the absence of Treg cells. We examined whether this E2-induced inhibitory activity of BM-DC might involve costimulation through the recently described PD-1 pathway. Both E2 and pregnancy markedly enhanced PD-1 expression in several types of APC, including macrophages, B cells, and especially dendritic cells (DC). Similarly to E2-induced enhancement of FoxP3 expression and experimental autoimmune encephalomyelitis protection, E2-induced enhancement of PD-1+ cells was also mediated through estrogen receptor alpha (Esr1) in DC and macrophages but not in B cells. Based on antibody inhibition studies, PD-1 interaction with its ligands, PDL-1 and especially PDL-2, could mediate either positive or negative regulatory signaling in both mature and immature E2-conditioned DC, depending, respectively, on a relatively high (10:1) or low (1:1) ratio of T cells:BM-DC. These novel findings indicate that E2-induced immunomodulation is mediated in part through potentiation in BM-DC of the PD-1 costimulatory pathway. © 2006 Wiley-Liss, Inc. [source] Tumor necrosis factor , blockade exacerbates murine psoriasis-like disease by enhancing Th17 function and decreasing expansion of Treg cellsARTHRITIS & RHEUMATISM, Issue 2 2010Hak-Ling Ma Objective Patients with psoriasis and psoriatic arthritis respond well to tumor necrosis factor , (TNF,) blockers in general; however, there is now mounting evidence that a small cohort of patients with rheumatoid arthritis who receive TNF, blockers develop psoriasis. This study was undertaken to explore the mechanisms underlying TNF, blockade,induced exacerbation of skin inflammation in murine psoriasis-like skin disease. Methods Skin inflammation was induced in BALB/c scid/scid mice after they received CD4+CD45RBhighCD25, (naive CD4) T cells from donor mice. These mice were treated with either anti,interleukin-12 (anti,IL-12)/23p40 antibody or murine TNFRII-Fc fusion protein and were examined for signs of disease, including histologic features, various cytokine levels in the serum, and cytokine or FoxP3 transcripts in the affected skin and draining lymph node (LN) cells. In a separate study, naive CD4+ T cells were differentiated into Th1 or Th17 lineages with anti-CD3/28 magnetic beads and appropriate cytokines in the presence or absence of TNF,. Cytokine gene expression from these differentiated cells was also determined. Results Neutralization of TNF, exacerbated skin inflammation and markedly enhanced the expression of the proinflammatory cytokines IL-1,, IL-6, IL-17, IL-21, and IL-22 but suppressed FoxP3 expression in the skin and reduced the number of FoxP3-positive Treg cells in the draining LNs. TNF, also demonstrated a divergent role during priming and reactivation of naive T cells. Conclusion These results reveal a novel immunoregulatory role of TNF, on Th17 and Treg cells in some individuals, which may account for the exacerbation of skin inflammation in some patients who receive anti-TNF treatments. [source] Dysfunctional CD4+,CD25+ regulatory T cells in untreated active systemic lupus erythematosus secondary to interferon-,,producing antigen-presenting cellsARTHRITIS & RHEUMATISM, Issue 3 2008Bing Yan Objective To explore whether there are extrinsic factors that impair the suppressive function of CD4+,CD25+ regulatory T cells in patients with untreated active systemic lupus erythematosus (SLE). Methods We studied 15 patients with untreated active SLE, 10 patients with SLE in remission, and 15 healthy control subjects. Percentages of CD4+,CD25+,FoxP3+ Treg cells and levels of forkhead box P3 (FoxP3) protein were analyzed by flow cytometry. Expression of messenger RNA (mRNA) for FoxP3 in purified Treg cell populations was assessed by real-time polymerase chain reaction analysis. Experiments examining Treg cell function in SLE were designed to distinguish primary from secondary T cell dysfunction. Levels of interferon-, (IFN,) in supernatants from the function assays were determined with an IFN-stimulated response element,luciferase reporter assay. Results The percentage of CD4+,CD25+, FoxP3+ cells in peripheral blood was significantly increased in SLE patients as compared with controls (mean ± SEM 9.11 ± 0.73% versus 4.78 ± 0.43%; P < 0.0001). We found no difference in FoxP3 expression at either the mRNA or protein level in any CD4+,CD25+ T cell subset from SLE patients as compared with controls. Antigen-presenting cells (APCs) from SLE patients were responsible for decreased Treg cell activity and could also render dysfunctional Treg cells from healthy control subjects. CD4+,CD25+ Treg cells from SLE patients exhibited normal suppressive activity when cultured with APCs from healthy controls. A partial Treg cell blockade effect was induced by the high levels of IFN, derived from SLE patient APCs. Conclusion We suggest that blockade of Treg cell,mediated suppression by IFN,-producing APCs in SLE patients may contribute to a pathogenic loss of peripheral tolerance in this disease. [source] DNA methylation controls Foxp3 gene expressionEUROPEAN JOURNAL OF IMMUNOLOGY, Issue 6 2008Julia Abstract Compelling evidence suggests that Foxp3-expressing CD25+CD4+ regulatory T cells (Treg) are generated within the thymus as a separate lineage. However, Foxp3+CD4+ Treg can also be generated de novo in a TGF-,-dependent process from naive T cells by TCR triggering. Recently, we have shown that naturally occurring, but not in vitro TGF-,-induced Foxp3+ Treg display stable Foxp3 expression that was associated with selective demethylation of an evolutionarily conserved element within the Foxp3 locus named TSDR (Treg-specific demethylated region). Here, we report that inhibition of DNA methylation by azacytidine, even in absence of exogenous TGF-,, not only promoted de novo induction of Foxp3 expression during priming, but also conferred stability of Foxp3 expression upon restimulation. Most notably, such stable Foxp3 expression was found only for cells displaying enhanced TSDR demethylation. In contrast, in vitro TSDR methylation diminished its transcriptional activity. Foxp3+ Treg generated in vivo by DEC-205-mediated targeting of agonist ligands to dendritic cells showed long-term survival in the absence of the inducing antigen and exhibited efficient TSDR demethylation. Together, our data suggest that TSDR is an important methylation-sensitive element regulating Foxp3 expression and demonstrate that epigenetic imprinting in this region is critical for establishment of a stable Treg lineage. Supporting Information for this article is available at www.wiley-vch.de/contents/jc_2040/2008/38105_s.pdf [source] ICER/CREM-mediated transcriptional attenuation of IL-2 and its role in suppression by regulatory T cellsEUROPEAN JOURNAL OF IMMUNOLOGY, Issue 4 2007Josef Bodor Dr. Abstract Here, we report that inducible cAMP early repressor/cAMP response element modulator (ICER/CREM) is induced early in CD25+CD4+ regulatory T cell (TR) assays mainly in activated Foxp3, effector T cells and this induction correlates with sharp decrease in number of IL-2-expressing T cells. Importantly, RNAi targeting of ICER/CREM in responder CD25,CD4+ T cells antagonizes TR -mediated suppression. Moreover, forced expression of Foxp3 in naive CD25, T cells induces constitutive expression of ICER/CREM in T cells with a regulatory phenotype. Foxp3 facilitates expression of ICER/CREM both in Foxp3 transductants as well as CD25, responder T cells suggesting that induction of TR function in suppression assays may utilize contact-dependent interaction. Indeed, CTLA-4 blockade or use of B7-deficient CD25, responder T cells prevents ICER/CREM accumulation and leads to the rescue of IL-2 expression. Therefore, we propose that CTLA-4 binding to B7 ligands expressed on activated ligand-bearing Foxp3, effector T cells results in ICER/CREM-mediated transcriptional attenuation of IL-2. Collectively, these data suggest that Foxp3 expression in TR cells imposes suppression in contact-dependent fashion by induction of constitutive ICER/CREM expression in activated CD25+ Foxp3, T cell effectors thus preventing them from producing IL-2. [source] Ex vivo expanded cord blood CD4 T lymphocytes exhibit a distinct expression profile of cytokine-related genes from those of peripheral blood originIMMUNOLOGY, Issue 3 2009Yoshitaka Miyagawa Summary With an increase in the importance of umbilical cord blood (CB) as an alternative source of haematopoietic progenitors for allogenic transplantation, donor lymphocyte infusion (DLI) with donor CB-derived activated CD4+ T cells in the unrelated CB transplantation setting is expected to be of increased usefulness as a direct approach for improving post-transplant immune function. To clarify the characteristics of activated CD4+ T cells derived from CB, we investigated their mRNA expression profiles and compared them with those of peripheral blood (PB)-derived activated CD4+ T cells. Based on the results of a DNA microarray analysis and quantitative real-time reverse transcriptase,polymerase chain reaction (RT-PCR), a relatively high level of forkhead box protein 3 (Foxp3) gene expression and a relatively low level of interleukin (IL)-17 gene expression were revealed to be significant features of the gene expression profile of CB-derived activated CD4+ T cells. Flow cytometric analysis further revealed protein expression of Foxp3 in a portion of CB-derived activated CD4+ T cells. The low level of retinoic acid receptor-related orphan receptor , isoform t (ROR,t) gene expression in CB-derived activated CD4+ T cells was speculated to be responsible for the low level of IL-17 gene expression. Our data indicate a difference in gene expression between CD4+ T cells from CB and those from PB. The findings of Foxp3 expression, a characteristic of regulatory T cells, and a low level of IL-17 gene expression suggest that CB-derived CD4+ T cells may be a more appropriate source for DLI. [source] Distinct regulatory roles of transforming growth factor-, and interleukin-4 in the development and maintenance of natural and induced CD4+ CD25+ Foxp3+ regulatory T cellsIMMUNOLOGY, Issue 1pt2 2009Jana Prochazkova Summary The development and function of CD4+ CD25+ Foxp3+ regulatory T cells (Tregs) are strictly regulated by cytokines. Here we show that transforming growth factor-, (TGF-,) and interleukin-4 (IL-4) play a crucial and antagonistic role in the development of Tregs. Additionally, these cytokines also have distinct effects on the maintenance of natural (nTregs) and antigen-induced (iTregs) Tregs. Using double-staining and tracking of proliferation of purified and carboxyflourescein succinimidyl ester (CFSE)-labelled mouse T-cell subpopulations we demonstrated that CD4+ CD25+ Foxp3+ iTregs develop upon alloantigenic stimulation in the presence of TGF-, exclusively from CD4+ CD25, Foxp3, precursors. Both the induction of Foxp3 expression and Treg proliferation were prevented when the cells were stimulated in the presence of IL-4. By contrast, nTregs did not proliferate in the presence of the antigen and TGF-,, and partially lost their Foxp3 expression. IL-4 not only prevented the development of iTregs, but also down-regulated the level of Foxp3 mRNA and decreased the number of Foxp3+ cells in a population of iTregs. Further analyses proved that IL-4 decreased the expression of Foxp3 only in a population of iTregs, whereas it substantially supported the survival of nTregs. Functional experiments showed that Tregs induced in the presence of alloantigen and TGF-, inhibited, on a per-cell basis, cell proliferation comparably to nTregs, and their suppressive capacity was not modulated by IL-4. These data suggest that TGF-, and IL-4 differentially regulate the development of Tregs and distinctly sustain Foxp3 expression and the number of nTregs and iTregs, but have no influence on the suppressive activity of Tregs on a per-cell basis. [source] Neuropilin-1 expression identifies a subset of regulatory T cells in human lymph nodes that is modulated by preoperative chemoradiation therapy in cervical cancerIMMUNOLOGY, Issue 1 2008Alessandra Battaglia Summary We examined the phenotype and function of CD4+ T cells expressing the semaphorin III receptor neuropilin-1 (Nrp1) in human lymph nodes and peripheral blood. In lymph nodes, Nrp1 identified a small regulatory CD4+ CD25high T-cell subpopulation (Nrp1+ Treg) that expressed higher levels of Forkhead box P3 (Foxp3) message and protein than Nrp1, Treg, and various molecular markers of activated Treg, i.e. CD45RO, human leucocyte antigen (HLA)-DR and glucocorticoid-induced tumour necrosis factor receptor (GITR). Similarly to conventional Treg, Nrp1+ Treg proliferated poorly in vitro, and exerted contact-dependent in vitro suppression of T-cell proliferation and cytokine secretion. However, Nrp1+ Treg were more efficient than Nrp1, Treg at inducing suppression. Nrp1 was also expressed on a small subpopulation of CD25int and CD25, CD4+ T cells that expressed more Foxp3, CD45RO, HLA-DR and GITR than their Nrp1, counterparts. In contrast, in peripheral blood Nrp1 identified a minor CD4+ T-cell subset that did not display the phenotypic features of Treg lacking Foxp3 expression and marginally expressing CD25. Hence, the function of Nrp1+ CD4+ T cells seemingly depends on their anatomical location. In a previous report, we proposed that Treg may curb the anti-tumour T-cell response in cervical cancer. We show here that Treg and Nrp1+ Treg levels dropped in the tumour-draining lymph nodes of patients with cervical cancer following preoperative chemoradiotherapy in a direct relationship with the reduction of tumour mass, suggesting that suppressor cell elimination facilitated the generation of T cells mediating the destruction of the neoplastic cells left behind after cytotoxic therapy. [source] The functional insufficiency of human CD4+CD25high T-regulatory cells in allergic asthma is subjected to TNF-, modulationALLERGY, Issue 1 2008Y.-L. Lin Background:, Natural CD4+CD25highFoxp3+ regulatory T (nTreg) cells are important in maintaining immunologic tolerance, but their role in the pathogenesis of allergic asthma is unclear. We studied the function of nTreg cells in allergic asthmatic children and assessed the factors which may relate to the functional insufficiency of nTreg cells. Methods:, The percentage of CD4+CD25high Treg cells, the expression of Foxp3, and the cell-induced suppressive activity of nTreg cells isolated from nonatopic controls, allergic asthmatics, and allergen-specific immunotherapy (AIT)-treated asthmatic patients were studied. Results:, Although the percentage of nTreg in peripheral blood mononuclear cells was increased, the expression of Foxp3 and its cell-induced suppressive activity were significantly lower in Dermatophagoides pteronyssinus (Der p)-sensitive asthmatic children when compared to nonatopic controls. In contrast, the expression of Foxp3 and the functional activity of nTreg cells were reversed in allergic asthmatics who received AIT. The addition of recombinant tumor necrosis factor (TNF)-, directly downregulated Foxp3 expression and abrogated the cell-induced suppressive function of Treg cells. The anti-TNF-, reagent, etanercept, restored the functional activity and Foxp3 expression of CD4+CD25high Treg derived from allergic asthmatics. Conclusions:, The functional insufficiency of nTreg cells in patients with allergic asthma may be related to the enhanced production of TNF-, and its effect on the Foxp3 expression. These results may explain, in part, the effectiveness of anti-TNF-, therapy in the treatment of allergic asthma. [source] Induction of IL-10+ CD4+ CD25+ regulatory T cells with decreased NF-,B expression during immunotherapyPEDIATRIC ALLERGY AND IMMUNOLOGY, Issue 1-Part-II 2010Yi-Giien Tsai Tsai Y-G, Chiou Y-L, Chien J-W, Wu H-P, Lin C-Y. Induction of IL-10+ CD4+ CD25+ regulatory T cells with decreased NF-,B expression during immunotherapy. Pediatr Allergy Immunol 2010: 21: e166,e173. © 2009 The Authors Journal compilation © 2009 Blackwell Munksgaard MyD88 is a major toll-like receptor (TLR) adaptor to activate NF-,B, which acts as a mater switch for allergic inflammation disease. Sterile hust dust extracts have been reported with TLR-dependent immunostimulatory activities. The aim of this study was to evaluate whether Dermatophagoides pteronyssinus (Der p) immunotherapy may increase IL-10+ CD4+ CD25+ T cells with modulating MyD88 signaling proteins, to decrease NF-,B expression. Peripheral blood mononuclear cells were isolated from patients before and after 1 yr of Der p immunotherapy, and also from matched control subjects. After 2 days of Der p-2 stimulation, intracellular IL-10 and Foxp3 expression of CD4+ CD25+ T cells were measured by flow-cytometry. The expression of IL-1 receptor-associated kinase (IRAK)-1 in cytoplasm and IFN-regulator factor-3 (IRF-3) with NF-,B/p65 in nuclei was determined by Western-blot analysis. Patients undergoing immunotherapy produced more soluble CD14, IL-10, and TGF-, that correlated with FEV1improvement (p < 0.05). In the immunotherapy group, the number of Foxp3+ CD4+ Treg cells increased more than the baseline status (25.06 ± 4.19 vs. 16.08 ± 3.54, p < 0.05). Additionally, increased IL-10 production with decreased IRAK-1 and NF-,B/p65 nuclear translocation was observed in sorted-purified Treg cells. IL-10+ CD4+ CD25+ Treg cells may respond to Der p-2 and down-regulate NF-,B/p65 expression to maintain immune tolerance during immunotherapy. [source] Rapamycin-Conditioned Donor Dendritic Cells Differentiate CD4+CD25+Foxp3+ T Cells In Vitro with TGF-,1 for Islet TransplantationAMERICAN JOURNAL OF TRANSPLANTATION, Issue 8 2010K. L. Pothoven Dendritic cells (DCs) conditioned with the mammalian target of rapamycin (mTOR) inhibitor rapamycin have been previously shown to expand naturally existing regulatory T cells (nTregs). This work addresses whether rapamycin-conditioned donor DCs could effectively induce CD4+CD25+Foxp3+ Tregs (iTregs) in cell cultures with alloantigen specificities, and whether such in vitro- differentiated CD4+CD25+Foxp3+ iTregs could effectively control acute rejection in allogeneic islet transplantation. We found that donor BALB/c bone marrow-derived DCs (BMDCs) pharmacologically modified by the mTOR inhibitor rapamycin had significantly enhanced ability to induce CD4+CD25+Foxp3+ iTregs of recipient origin (C57BL/6 (B6)) in vitro under Treg driving conditions compared to unmodified BMDCs. These in vitro- induced CD4+CD25+Foxp3+ iTregs exerted donor-specific suppression in vitro, and prolonged allogeneic islet graft survival in vivo in RAG,/- hosts upon coadoptive transfer with T-effector cells. The CD4+CD25+Foxp3+ iTregs expanded and preferentially maintained Foxp3 expression in the graft draining lymph nodes. Finally, the CD4+CD25+Foxp3+ iTregs were further able to induce endogenous naïve T cells to convert to CD4+CD25+Foxp3+ T cells. We conclude that rapamycin-conditioned donor BMDCs can be exploited for efficient in vitro differentiation of donor antigen-specific CD4+CD25+Foxp3+ iTregs. Such in vitro- generated donor-specific CD4+CD25+Foxp3+ iTregs are able to effectively control allogeneic islet graft rejection. [source] Glucocorticoids increase CD4+CD25high cell percentage and Foxp3 expression in patients with multiple sclerosisACTA NEUROLOGICA SCANDINAVICA, Issue 4 2009M. Braitch Objectives,,, To determine whether percentages of CD4+CD25high T cells (a group of regulatory T cells, Treg) differ in patients with multiple sclerosis (MS) in relapse vs remission after glucocorticoid treatment and whether treatment for relapses changes Treg population and the expression of Foxp3, a key Treg-associated molecule. Materials and methods,,, Peripheral blood mononuclear cells (PBMC) were obtained from 20 patients with MS during relapse, just before and 2 days after starting steroid treatment (i.v. methylprednisolone 1 g/day for 3 days) and then 6 weeks after treatment. CD4+CD25hi cells were analysed by using flow cytometry. Cytokines were measured by using an ELISA and Foxp3, CD3 and CD25 expression by using quantitative real-time PCR. Results,,, The percentage of CD4+CD25hi cells, plasma IL-10 and Foxp3/CD3 ratio increased 48 h after methylprednisolone initiation and returned to baseline values by 6 weeks post-treatment. Conclusions,,, Results suggest that glucocorticoids increase Treg cell functional molecules and percentages. This may be a mechanism whereby steroids expedite recovery from MS relapses. [source] Seasonal changes in suppressive capacity of CD4+ CD25+ T cells from patients with hayfever are allergen-specific and may result in part from expansion of effector T cells among the CD25+ populationCLINICAL & EXPERIMENTAL ALLERGY, Issue 11 2009A. E. Anderson Summary Background Suppression of allergen-stimulated peripheral blood CD4+ CD25, effector T cells by CD4+ CD25+ regulatory T cells obtained from subjects with allergic rhinoconjunctivitis is reduced during the pollen season when compared with out of season. Objective We examined possible explanations for this effect of seasonal pollen exposure on suppression of allergen responses. Methods CD4+ CD25, and CD4+ CD25+ T cells were isolated from blood obtained from 44 volunteers with allergic rhinoconjunctivitis during and out of the UK grass pollen season. Co-cultures were performed with grass pollen extract and house dust mite (HDM) to examine allergen specificity. The frequency of IL-5 and IL-10 producing cells was determined by ELISPOT and the expression of T cell activation markers and the CD25+ regulatory T cell-associated transcription factor Foxp3 were examined. Lactic acid stripping of IgE was used to determine IgE dependence of T cell responses. Results The seasonal reduction in suppression by CD4+ CD25+ T cells was confirmed and was shown to be allergen specific because suppression of HDM-stimulated cultures was not affected significantly. The CD4+ CD25+ population contained IL-5 and IL-10 producing cells but increases in their frequencies with seasonal pollen exposure were not significant. Both activation marker and Foxp3 expression increased during the pollen season. IgE stripping reduced CD4+ and CD4+ CD25, T cell responses to allergen, but had no effect on suppression by CD4+ CD25+ T cells. Conclusion The seasonal reduction in suppression of grass pollen-stimulated effector T cells by CD4+ CD25+ T cells is allergen specific and cannot be explained by increased IgE-facilitated allergen presentation. We suggest that changes in the proportion of effector to regulatory T cells among the CD25+ population isolated may partially explain these findings, and that trafficking to the site of allergic disease may reduce allergen-specific regulatory T cell numbers in peripheral blood. [source] Regulatory T cells and asthmaCLINICAL & EXPERIMENTAL ALLERGY, Issue 9 2009D. S. Robinson Airway inflammation in asthma is characterized by activation of T helper type-2 (Th2) T cells, IgE production and eosinophilia. In many cases, this process is related to an inappropriate T cell response to environmental allergens, and other T cell-dependent pathways may also be involved (such as Th17). Regulatory T cells (Tregs) are T cells that suppress potentially harmful immune responses. Two major subsets of Treg are CD25hi, Foxp3+Tregs and IL-10-producing Tregs. There is evidence that the numbers or function of both subsets may be deficient in patients with atopic allergic disease. Recent work has extended these findings into the airway in asthma where Foxp3 expression was reduced and CD25hi Treg-suppressive function was deficient. In animal models of allergic airways disease, Tregs can suppress established airway inflammation and airway hyperresponsiveness, and protocols to enhance the development, recruitment and function of Tregs have been described. Together with studies of patients and in vitro studies of human T cells, these investigations are defining potential interventions to enhance Treg function in the airway in asthma. Existing therapies including corticosteroids and allergen immunotherapy act on Tregs, in part to increase IL-10 production, while vitamin D3 and long-acting ,-agonists enhance IL-10 Treg function. Other possibilities may be enhancement of Treg function via histamine or prostanoid receptors, or by blocking pro-inflammatory pathways that prevent suppression by Tregs (activation of Toll-like receptors, or production of cytokines such as IL-6 and TNF-,). As Tregs can also suppress the potentially beneficial immune response important for controlling infections and cancer, a therapeutic intervention should target allergen- or site-specific regulation. [source] | ||||||||||||||||||||||||||||