CD25 Foxp3 Research Articles

T regulatory cell phenotypes in peripheral blood and bronchoalveolar lavage from non-asthmatic and asthmatic subjects.

An unresolved issue in T regulatory cells' cell biology is the lack of consensus on phenotypic markers that accurately define the natural Treg (nTreg) population. To examine nTreg frequency and functional capacity in healthy controls and their frequency in asthmatic subjects using three different phenotypic strategies. We hypothesized that phenotypically different nTreg are quantitatively and functionally different. Thirty-four healthy, non-asthmatic and 17 asthmatic subjects were studied. Three nTreg phenotypes were defined as follows: nTreg1 (CD4(+) CD25(+) Foxp3(+) ), nTreg2 (CD4(+) CD25(+) CD127(low) Foxp3(+) ), and nTreg3 (CD4(+) CD25(high) Foxp3(+) ). The flow cytometric determination of nTreg frequency in peripheral blood (PB) and bronchoalveolar lavage (BAL) was performed using fluorescently labelled antibodies. Peripheral blood nTreg functional capacity was assessed using a CFSE-based suppression assay. There was a significantly lower frequency of PB nTreg3 compared to nTreg2 and nTreg1 (P<0.05). Both nTreg2 and nTreg3 had a significantly greater suppressive capacity than nTreg1 at T responder (Tresp) to nTreg ratios of 16:1 up to 1:1 (P<0.01). Asthmatics exhibited a significantly lower PB nTreg3 and nTreg1 frequency than healthy controls (P<0.05). There were no differences between healthy controls and asthmatic subjects when comparing BAL nTreg frequency. Phenotypically different nTreg subsets are quantitatively and functionally different and are variably observed in asthma. The CD4(+) CD25(high) Foxp3(+) phenotype was the least frequent, but demonstrated the greatest suppression, and was significantly lower in PB of asthmatic subjects. Consequently, it is imperative that nTreg phenotypes be clearly defined and that the interpretation of their frequency and function be phenotype specific.

Up-regulated S100 calcium binding protein A8 in Plasmodium-infected patients correlates with CD4(+)CD25(+)Foxp3 regulatory T cell generation.

BackgroundThe pro-inflammatory S100 calcium binding protein A8 (S100A8) is elevated in the serum of patients with Plasmodium falciparum malaria, but its function in Plasmodium vivax malaria is not yet clear. This function was investigated in P. vivax-infected patients in this study.MethodsThe level of S100A8 in the serum was measured with ELISA. Full amino acids of S100A8 were synthesized to verify the functions for maturation of immature dendritic cell (iDC) and evaluation of CD4+CD25+Foxp3+ regulatory T (Treg) generation by mature DC (mDC).ResultsA higher amount of S100A8 was detected in vivax-infected patients (141.2 ± 61.849 ng/ml, n = 40) compared with normal control group (48.1 ± 27.384 ng/ml, n = 40). The level of S100A8 did not coincide with that of anti-malarial antibody measured by indirect fluorescent antibody test (IFAT) using parasite-infected red blood cells as antigen. Programmed death-ligand 1 (PD-L1) was up-regulated on the surface of iDCs following treatment with synthetic S100A8, not with synthetic MSP-1, AMA-1 and CSP, as compared to the expression seen for non-treated iDCs. The addition of red blood cells of infected patients to iDCs also elevated their surface expression of CD86. However, the serum levels of S100A8 decreased with increase in parasitaemia. DCs matured by sera containing S100A8 generated Treg cells from naïve T cells. The ratio of Treg cells generated was inversely proportional to the concentration of S100A8 in sera.ConclusionsTreg cells suppress the activity of cytotoxic T cells, which kill malaria parasites; therefore, the up-regulation of S100A8 in malaria patients may contribute to pathogen immune escape or tolerance.

Decreased T Follicular Regulatory Cell/T Follicular Helper Cell (TFH) in Simian Immunodeficiency Virus-Infected Rhesus Macaques May Contribute to Accumulation of TFH in Chronic Infection.

T follicular helper cells (TFH) are critical for the development and maintenance of germinal center (GC) and humoral immune responses. During chronic HIV/SIV infection, TFH accumulate, possibly as a result of Ag persistence. The HIV/SIV-associated TFH expansion may also reflect lack of regulation by suppressive follicular regulatory CD4(+) T cells (TFR). TFR are natural regulatory T cells (TREG) that migrate into the follicle and, similar to TFH, upregulate CXCR5, Bcl-6, and PD1. In this study, we identified TFR as CD4(+)CD25(+)FOXP3(+)CXCR5(+)PD1(hi)Bcl-6(+) within lymph nodes of rhesus macaques (RM) and confirmed their localization within the GC by immunohistochemistry. RNA sequencing showed that TFR exhibit a distinct transcriptional profile with shared features of both TFH and TREG, including intermediate expression of FOXP3, Bcl-6, PRDM1, IL-10, and IL-21. In healthy, SIV-uninfected RM, we observed a negative correlation between frequencies of TFR and both TFH and GC B cells, as well as levels of CD4(+) T cell proliferation. Post SIV infection, the TFR/TFH ratio was reduced with no change in the frequency of TREG or TFR within the total CD4(+) T cell pool. Finally, we examined whether higher levels of direct virus infection of TFR were responsible for their relative depletion post SIV infection. We found that TFH, TFR, and TREG sorted from SIV-infected RM harbor comparable levels of cell-associated viral DNA. Our data suggest that TFR may contribute to the regulation and proliferation of TFH and GC B cells in vivo and that a decreased TFR/TFH ratio in chronic SIV infection may lead to unchecked expansion of both TFH and GC B cells.

Enrichment of regulatory T-cells in blood of patients with multidrug-resistant tuberculosis.

To measure the percentage of regulatory T-cells (Treg) and the expression of signalling molecules in these cells from the peripheral blood of patients with multidrug-resistant tuberculosis (MDR-TB). Patients with drug-susceptible tuberculosis (S-TB), MDR-TB and healthy controls (HCs) were recruited into the study. Levels of CD4(+)CD25(+)Foxp3(+) Treg cells from peripheral blood, and programmed death-1 (PD-1), cytotoxic T lymphocyte-associated antigen-4 (CTLA-4) and inducible costimulatory (ICOS) molecule expression in the cells were measured using flow cytometry. Suppression mediated by Treg cells was assessed in carboxyfluorescein succinimidyl ester (CFSE) based suppression assays with autologous CD4(+)CD25(-) T-effector (Teff) cells. Presence of Mycobacterium tuberculosis resulted in a higher proportion of Treg cells in S-TB patients than in HCs, and even higher levels in MDR-TB patients. Moreover, Treg cells in MDR-TB patients constitutively expressed high-level PD-1, CTLA-4 and ICOS. In addition, when cultured with activated CD4(+)CD25(-) Teff cells, Treg cells potently suppressed proliferation of Teff cells. The high level of Treg cells found in the peripheral blood of tuberculosis patients may partly explain the poor immune response against M. tuberculosis, and could be a marker of MDR-TB.

Immune modulation of T regulatory cells and IgE responses in horses vaccinated with West Nile virus vaccine combined with a CpG ODN

Hypersensitivity reactions, such as hives or fatal anaphylactic shock, in response to vaccination constitute a health hazard for horses that develop allergies to vaccine components. In such horses vaccination with viral vaccines stimulates an IgE response to non-target antigens. Viral vaccines share contaminating non-target proteins, such as bovine serum albumin (BSA); these antigens can stimulate IgE production with each exposure. We hypothesized that the addition of a CpG oligodeoxynucleotide (ODN) administered in conjunction with a West Nile virus vaccine would decrease the IgE response; through up-regulation of T regulatory cells and T helper 1 cells thus decreasing the potential to induce a type 1 hypersensitivity response. Thirty adult horses were injected with either CpG ODN or control GpC ODN with a killed WNV vaccine. T regulatory cell numbers and BSA specific IgE concentrations were determined pre and post vaccination. Multicolor flow cytometry was used to evaluate expression of CD4, CD25, and intracellular Foxp3 on PBMCs. Serum concentrations of BSA specific IgE were determined by ELISA. Cell culture supernatants from BSA re-stimulated lymphocytes were evaluated for concentrations of IL-2, IL-4, IL-10, and IFN-γ. The inclusion of the CpG ODN significantly increased the differentiation of T regulatory cells in response to antigen in vitro and in vivo. A significant inverse correlation was found between T regulatory cell numbers and serum BSA specific IgE concentrations. These results suggest that we can provide a safer alternate vaccination strategy, particularly for horses that have demonstrated a pro-allergic phenotype.

The imbalance between Tregs, Th17 cells and inflammatory cytokines among renal transplant recipients.

BackgroundA significant barrier to organ transplantation is the cellular rejection that occurs and mediated by antibodies, T cells, and innate immune cells. This study was aimed to determine the number of CD4+CD25+Foxp3+ Treg, CD4+IFN-γ−IL-17+ Th17, CD4+IFN-γ+IL-17− Th1 and CD4+IFN-γ+IL-17+ Th1/17 cells in renal transplant recipients (RTR).MethodsRenal transplantation was performed for a total of 35 patients with end-stage renal failure. The number of CD4+CD25+Foxp3+ Treg, CD4+IFN-γ−IL-17+ Th17, CD4+IFN-γ+IL-17− Th1 and CD4+IFN-γ+IL-17+ Th1/17 cells, and the serum level of IFN-γ, TNF-α, IL-2, IL-4, IL-6, IL-10, and IL-17 were measured in pre- and post-transplant patients and 10 healthy controls (HC) using flow cytometry and Cytometric Bead Array (CBA). The association between the number of different subsets of CD4+ T-cells and clinical parameters were analyzed among the pre- and post-transplant patients, and the healthy controls.ResultsThe number of CD4+IFN-γ−IL-17+ Th17, CD4+IFN-γ+IL-17− Th1 and CD4+IFN-γ+IL-17+ Th1/17 cells were significantly increased in patients with End-Stage Renal Failure (ESRF) compared to the HC. Stratification analysis indicated that AMR (Acute antibody mediated acute rejection), AR (acute rejection) and CR (chronic rejection) groups displayed greater number of CD4+IFN-γ−IL-17+ Th17, CD4+IFN-γ+IL-17− Th1 and CD4+IFN-γ+IL-17+ Th1/17 cells as well as high level of serum IL-2, IFN-γ, TNF-α and IL-17. But, the AMR, AR and CR groups have shown lower level of CD4+CD25+Foxp3+ T cells and serum IL-10 compared to transplant stable (TS) patients. Moreover, the number of Tregs were negatively correlated with the number of Th17 cells in RTR patients. The number of Tregs and Th17 cells were positively correlated with the eGFR and serum creatinine values, respectively.ConclusionThe imbalance between different types of CD4+ T cells and dysregulated inflammatory cytokines may contribute towards renal transplantation rejection.

High proportions of regulatory T cells in PBSC grafts predict improved survival after allogeneic haematopoietic SCT

Regulatory T cells (Tregs) modulate immune responses and improve survival in murine transplant models. However, whether the Treg content of allogeneic cell grafts influences the outcome in human haematopoietic stem cell (HSC) transplantation is not well established. In a prospective study of 94 adult allogeneic PBSC transplants (60% unrelated; 85% reduced intensity conditioning), the median Treg (CD3+CD4+CD25+FOXP3+CD127dim/−) dose transplanted was 4.7 × 106/kg, with Tregs accounting for a median of 2.96% of CD4+ T cells. Patients transplanted with grafts containing a Treg/CD4+ T-cell ratio above the median had a 3-year overall survival of 75%, compared with 49% in those receiving grafts with a Treg/CD4+ T-cell ratio below the median (P=0.02), with a 3-year non-relapse mortality of 13% and 35%, respectively (P=0.02). In multivariate analysis, a high graft Treg/CD4+ T-cell ratio was an independent predictor of lower non-relapse mortality (hazard ratio (HR), 0.30; P=0.02), improved overall survival (HR, 0.45; P=0.03) and improved sustained neutrophil (HR, 0.52; P=0.002), platelet (HR, 0.51; P<0.001) and lymphocyte (HR, 0.54; P=0.009) recovery. These data support the hypothesis that the proportion of Tregs in allogeneic HSC grafts influences clinical outcome and suggest that Treg therapies could improve allogeneic HSC transplantation.

The Role of Iodine and Selenium in Autoimmune Thyroiditis.

Iodine and selenium (Se) are both essential elements to thyroid hormone economy, while they represent key players in the development of autoimmune thyroiditis.Chronic high iodine intake has been associated in various studies with increased frequency of autoimmune thyroiditis. In susceptible individuals, iodine excess increases intra-thyroid infiltrating Th17 cells and inhibits T regulatory (TREG) cells development, while it triggers an abnormal expression of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) in thyrocytes, thus inducing apoptosis and parenchymal destruction. As was shown in a mouse model, high iodine supply leads to changes in the immunogenicity of the thyroglobulin molecule, upregulation of vascular intercellular adhesion molecule-1 (ICAM-1), and reactive oxygen species (ROS) generation in the thyrocytes. Serum Se levels were found decreased in Hashimoto thyroiditis and especially in Graves' disease as well as in thyroid-associated ophthalmopathy patients, the levels being related to the pathogenesis and outcome. Selenium is strongly involved, via the variable selenoproteins, in antioxidant, redox, and anti-inflammatory processes. Selenium enhances CD4+/CD25 FOXP3 and T regulatory cells activity while suppressing cytokine secretion, thus preventing apoptosis of the follicular cells and providing protection from thyroiditis. Selenium supplementation may be useful in autoimmune thyroid diseases, though, while usually well-tolerated, it should not be universally recommended, and it is also likely to be helpful for those with low Se status and autoimmunity. Broadly speaking, the achievement and maintenance of "selenostasis" as well as adequate urinary iodine excretion are mandatory to control disease, while, putatively, they may additionally be critical to preventing disease.

Double-Negative αβ T Cells Are Early Responders to AKI and Are Found in Human Kidney.

Ischemia-reperfusion injury (IRI) is a major cause of AKI, and previous studies established important roles for conventional CD4(+) T cells, natural killer T cells, and CD4(+)CD25(+)FoxP3(+) Tregs in AKI pathogenesis. We recently identified CD4(-)CD8(-) (double-negative; DN) T cells as an important subset of αβ T cell receptor-positive cells residing in mouse kidney. However, little is known about the pathophysiologic functions of kidney DN T cells. In this study, we phenotypically and functionally characterized murine kidney DN T cells in the steady state and in response to IRI. Unlike CD4(+) and CD8(+) T cells, DN T cells in the steady state expressed high levels of CD69, CD28, and CD40L; differentially expressed IL-27 and IL-10 anti-inflammatory cytokines; spontaneously proliferated at a very high rate; and suppressed in vitro proliferation of activated CD4(+) T cells. Within the first 3-24 hours after IRI, kidney DN T cells expanded significantly and upregulated expression of IL-10. In adoptive transfer experiments, DN T cells significantly protected recipients from AKI by an IL-10-dependent mechanism. DN T cells also made up a large fraction of the T cell compartment in human kidneys. Our results indicate that DN T cells are an important subset of the resident αβ(+) T cell population in the mammalian kidney and are early responders to AKI that have anti-inflammatory properties.

Foxp3-modified bone marrow mesenchymal stem cells promotes liver allograft tolerance through the generation of regulatory T cells in rats.

BackgroundThe transcription factor forkhead box P3 (Foxp3) is a master regulatory gene necessary for the development and function of CD4+CD25+ regulatory T cells (Tregs). Mesenchymal stem cells (MSC) have recently emerged as promising candidates for cell-based immunosuppression/tolerance induction protocols. Thus, we hypothesized that MSC-based Foxp3 gene therapy would improve immunosuppressive capacity of MSC and induce donor-specific allograft tolerance in rat’s liver allograft model.MethodsThe present study utilized a lentivirus vector to overexpress the therapeutic gene Foxp3 on MSC. In vivo, Injections of 2 × 106 MSC, FUGW-MSC or Foxp3-MSC into the portal vein were carried out immediately after liver transplantation.ResultsSuccessful gene transfer of Foxp3 in MSC was achieved by lentivirus carrying Foxp3 and Foxp3-MSC engraftment in liver allograft was confirmed by fluorescence microscopy. Foxp3-MSC treatment significantly inhibited the proliferation of allogeneic ACI CD4+ T cells to splenocytes (SC) from the same donor strain or third-party BN rat compared with MSC. Foxp3-MSC suppressive effect on the proliferation of CD4+ T cells is contact dependent and associated with Programmed death ligand 1(PD-L1) upregulation in MSC. Co-culture of CD4+ T cells with Foxp3-MSC results in a shift towards a Tregs phenotype. More importantly, Foxp3-MSC monotherapy achieved donor-specific liver allograft tolerance and generated a state of CD4+CD25+Foxp3+ Tregs-dependent tolerance.ConclusionFoxp3-engineered MSC therapy seems to be a promising and attractive cell therapy approach for inducing immunosuppression or transplant tolerance.

Immunomodulation of host-protective immune response by regulating Foxp3 expression and Treg function in Leishmania-infected BALB/c mice: critical role of IRF1.

Visceral leishmaniasis (VL), caused by a protozoan parasite Leishmania donovani, is still a threat to mankind due to treatment failure, drug resistance and coinfection with HIV. The limitations of first-line drugs have led to the development of new strategies to combat this dreaded disease. Recently, we have shown the immunomodulatory property of Ara-LAM, a TLR2 ligand, against leishmanial pathogenesis. In this study, we have extended our study to the effect of Ara-LAM on regulatory T cells in a murine model of VL. We observed that Ara-LAM-treated infected BALB/c mice showed a strong host-protective Th1 immune response due to reduced IL-10 and TGF-β production, along with marked decrease in CD4(+) CD25(+) Foxp3(+) GITR(+) CTLA4(+) regulatory T cell (Treg) generation and activation. The reduction in Foxp3 expression was due to effective modulation of TGF-β-induced SMAD signaling in Treg cells by Ara-LAM. Moreover, we demonstrated that Ara-LAM-induced IRF1 expression in the Treg cells, which negatively regulated foxp3 gene transcription, resulting in the reduced immunosuppressive activity of Treg cells. Interestingly, irf1 gene knockdown completely abrogated the effect of Ara-LAM on Treg cells. Thus, these findings provide detailed mechanistic insight into Ara-LAM-mediated modulation of Treg cells, which might be helpful in combating VL.

T Lymphocyte-Specific Activation of Nrf2 Protects from AKI.

T lymphocytes are established mediators of ischemia reperfusion (IR)-induced AKI, but traditional immune principles do not explain their mechanism of early action in the absence of alloantigen. Nrf2 is a transcription factor that is crucial for cytoprotective gene expression and is generally thought to have a key role in dampening IR-induced AKI through protective effects on epithelial cells. We proposed an alternative hypothesis that augmentation of Nrf2 in T cells is essential to mitigate oxidative stress during IR-induced AKI. We therefore generated mice with genetically amplified levels of Nrf2 specifically in T cells and examined the effect on antioxidant gene expression, T cell activation, cytokine production, and IR-induced AKI. T cell-specific augmentation of Nrf2 significantly increased baseline antioxidant gene expression. These mice had a high frequency of intrarenal CD25(+)Foxp3(+) regulatory T cells and decreased frequencies of CD11b(+)CD11c(+) and F4/80(+) cells. Intracellular levels of TNF-α, IFN-γ, and IL-17 were significantly lower in CD4(+) T cells with high Nrf2 expression. Mice with increased T cell expression of Nrf2 were significantly protected from functional and histologic consequences of AKI. Furthermore, adoptive transfer of high-Nrf2 T cells protected wild-type mice from IR injury and significantly improved their survival. These data demonstrate that T cell-specific activation of Nrf2 protects from IR-induced AKI, revealing a novel mechanism of tissue protection during acute injury responses.

CD4(+)CD25(-)Foxp3(+) T cells play a role in tuberculous hydrothorax rather than malignant hydrothorax.

BackgroundFoxp3+ T cells regulate inflammation and tumorigenesis. However, little is known about the role of different subsets of Foxp3+ T cells in malignant or tuberculous hydrothorax.MethodsThe numbers of CD4+CD25+Foxp3+, CD4+CD25−Foxp3+ T cells and the levels of some inflammatory cytokines in patients with tuberculous hydrothorax, malignant hydrothorax, and healthy controls (HCs) were examined by flow cytometry and ELISA. The potential association between the numbers of different subsets of Foxp3 + T cells and the values of clinical measures were analyzed.ResultsThe numbers of peripheral blood CD4+CD25+Foxp3+ T cells were greater in malignant hydrothorax patients than in HCs, but fewer than those of hydrothorax in patients. The percentages of circulating IL-10+ or LAP+ CD4+CD25+Foxp3+ T cells were higher than in the hydrothorax in patients with malignant hydrothorax. The numbers of circulating CD4+CD25−Foxp3+ T cells were significantly fewer in patients with tuberculous hydrothorax than in HCs, and both the numbers of circulating CD4+CD25+Foxp3+ and CD4+CD25−Foxp3+ T cells were significantly fewer than in the hydrothorax in patients. Significantly higher percentages of circulating IL-10+ or LAP+ CD4+CD25+Foxp3+ and CD4+CD25−Foxp3+ T cells were detected in tuberculous hydrothorax patients. The numbers of CD4+CD25+Foxp3+ and CD4+CD25−Foxp3+ T cells were associated with hydrothorax adenosine deaminase (ADA) levels in tuberculous hydrothorax patients, while CD4+CD25+Foxp3+ T cells were associated with carcino-embryonic antigen (CEA) in malignant hydrothorax patients. The concentrations of serum IL-6 and TGF-β in the patients were significantly higher than that in the HCs, but lower than that in the corresponding hydrothorax. A similar pattern of IL-10 was observed in different groups, except that there was no significant difference in the levels of serum IL-10 between the tuberculous hydrothorax patients and HCs.ConclusionsCD4+CD25−Foxp3+ T cells, which have lower inhibitory function than CD4+CD25+Foxp3+ T cells, may play a role in tuberculous hydrothorax.

Impairment of dendritic cell function and induction of CD4(+)CD25(+)Foxp3(+) T cells by excretory-secretory products: a potential mechanism of immune evasion adopted by Echinococcus granulosus.

BackgroundCystic echinococcosis, caused by infection with Echinococcus granulosus, is one of the most widespread zoonotic helminth diseases. Modulation of host responses is an important strategy used by helminth parasites to promote infection. To better understand the mechanisms adopted by E. granulosus to escape host immune responses, we investigated the effects of excretory–secretory products (ES) and adult worm antigen (AWA) derived from adult E. granulosus on murine bone marrow-derived dendritic cells (BMDC).ResultsCompared with lipopolysaccharide (LPS), AWA, but not ES, induced BMDC maturation or stimulated BMDC cytokine production and co-stimulatory molecule expression (CD40, CD80 and MHC class II). Furthermore, ES-treated BMDCs pulsed with ovalbumin exhibited reduced co-stimulatory molecule expression in comparison with untreated BMDC, even in the presence of the strong Th1 inducer, CpG. Moreover, we detected the effects of ES-treated DC on T cell activation by an in vitro T cell priming assay. We observed that ES-treated BMDC co-cultured with DO11.10 transgenic CD4+ T cells induced the generation of CD4+CD25+Foxp3+ T cells. In addition, in contrast to AWA-treated BMDCs, which had markedly induced IFN-γ secretion and reduced of IL-4 levels in co-cultured T cells, ES-treated BMDCs did not modify their capacity to stimulate IFN-γ or IL-4 production by T cells.ConclusionsWe conclude that ES of adult E. granulosus inhibited DC function, impaired the development of Th1 cells induced by CpG, and induced CD4+CD25+Foxp3+ regulatory T cells in an IL-10-independent manner.

Role of Regulatory T Cells (Treg) and the Treg Effector Molecule Fibrinogen-like Protein 2 in Alloimmunity and Autoimmunity.

CD4+CD25+Foxp3+ regulatory T cells (Treg) are critical to the maintenance of immune tolerance. Treg are known to utilize a number of molecular pathways to control immune responses and maintain immune homeostasis. Fibrinogen-like protein 2 (FGL2) has been identified by a number of investigators as an important immunosuppressive effector of Treg, which exerts its immunoregulatory activity by binding to inhibitory FcγRIIB receptors expressed on antigen-presenting cells including dendritic cells, endothelial cells, and B cells. More recently, it has been suggested that FGL2 accounts for the immunosuppressive activity of a highly suppressive subset of Treg that express T cell immunoreceptor with Ig and ITIM domains (TIGIT). Here we discuss the important role of Treg and FGL2 in preventing alloimmune and autoimmune disease. The FGL2–FcγRIIB pathway is also known to be utilized by viruses and tumor cells to evade immune surveillance. Moving forward, therapies based on modulation of the FGL2–FcγRIIB pathway hold promise for the treatment of a wide variety of conditions ranging from autoimmunity to cancer.

Interleukin‐6 controls uterine Th9 cells and CD8+ T regulatory cells to accelerate parturition in mice

Interleukin-6 (IL6) is a determinant of the timing of parturition and birth in mice. We previously demonstrated that genetic IL6 deficiency delays parturition by ~24 h, and this is restored by administration of exogenous IL6. In this study, we have investigated whether IL6 influences the number or phenotypes of T cells or other leukocytes in uterine decidual tissue at the maternal-fetal interface. In late gestation, decidual leukocytes in Il6 null mutant (Il6(-/-)) mice exhibit an altered profile, characterized by reduced numbers of cells expressing the monocyte/macrophage marker F4/80 or the T-cell marker CD4, increased cells expressing the natural killer (NK) cell marker CD49b or the dendritic cell marker CD11c, but no change in cells expressing the neutrophil marker Ly6G. These changes are specific to late pregnancy, as similar differences in decidual leukocytes were not evident in mid-gestation Il6(-/-) mice. The IL6-regulated changes in decidual NK and dendritic cells appear secondary to local recruitment, as no comparable changes occurred in peripheral blood of Il6(-/-) mice. When exogenous IL6 was administered to restore normal timing of parturition, a partial reversal of the altered leukocyte profile was observed, with a 10% increase in the proportion of decidual CD4(+) T cells, a notable 60% increase in CD8(+) T cells including CD8(+)CD25(+)Foxp3(+) regulatory T cells and a 60% reduction in CD4(+)IL9(+) Th9 cells. Together these findings suggest that IL6-controlled accumulation of decidual CD4(+) T cells and CD8(+) regulatory T cells, with an associated decline in decidual Th9 cells, is instrumental for progressing parturition in mice.

Nebulized fluticasone propionate, a viable alternative to systemic route in the management of childhood moderate asthma attack: A double-blind, double-dummy study

BackgroundIn this study, we compared the clinical and immunological efficacy of nebulized corticosteroid (CS) to systemic route during treatment of moderate asthma attack in children. MethodsIn this randomized, placebo-controlled, double-blind, double-dummy, prospective study, 81 children aged 12 months to 16 years experiencing asthma attack randomized into two treatment groups to receive, either; nebulized fluticasone propionate (n = 39, 2000 mcg/day) or oral methylprednisolone (n = 41, 1 mg/kg/day). Pulmonary index scores (PIS) were assessed at admission and at 1st, 4th, 8th, 12th, 24th, 48th hours, as well as, on day 7 and peak expiratory flow (PEF) at baseline and at the 7th day. Daily symptom and medication scores were recorded for all subjects. Immunological studies included phytohemagglutinin induced peripheral blood mononuclear cells culture supernatant for cytokine responses and CD4(+) CD25(+) FOXP3(+) T regulatory cell (T reg) percentage at baseline and day 7. ResultsThe changes in PIS and PEF were similar in both treatment groups, with a significant improvement in both values at the 7th day, when compared to baseline. In both groups, significant reductions in symptom and medication scores were observed during the treatment period with no significant difference between the groups. At day 7 of intervention, phytohemagglutinin induced IL-4 level was significantly decreased only in the nebulized group compared to baseline (p = 0.01). Evaluation of cytokine responses by means of fold increase (stimulated (S)/unstimulated (US) ratio) revealed a significant reduction in IL-4, IL-5 and IL-17 only in nebulized group (p = 0.01, 0.01, 0.02; respectively). The fold increase value of IL-5 was significantly lower at 7th day in nebulized group when compared to systemic one (p = 0.02). At 7th day, although in both treatment groups the percentage of T reg cells was suppressed, it remained significantly higher in the nebule one when compared to systemic route (p = 0.04). ConclusionIn the management of moderate acute asthma attack, nebulized CS (2000 mcg daily) was found to be as effective as systemic route with regard to clinical improvement. In addition, immunological parameters were more in favor of nebulized route which may imply a salutary effect of local CS usage.

The Essential Role of Circulating Thyroglobulin in Maintaining Dominance of Natural Regulatory T Cell Function to Prevent Autoimmune Thyroiditis.

Several key findings from the late 1960s to mid-1970s regarding thyroid hormone metabolism and circulating thyroglobulin composition converged with studies pertaining to the role of T lymphocytes in autoimmune thyroiditis. These studies cemented the foundation for subsequent investigations into the existence and antigenic specificity of thymus-derived natural regulatory T cells (nTregs). These nTregs prevented the development of autoimmune thyroiditis, despite the ever-present genetic predisposition, autoantigen (thyroglobulin), and thyroglobulin-reactive T cells. Guided by the hypothalamus-pituitary-thyroid axis as a fixed set-point regulator in thyroid hormone metabolism, we used a murine model and compared at key junctures the capacity of circulating thyroglobulin level (raised by thyroid-stimulating hormone or exogenous thyroglobulin administration) to strengthen self-tolerance and resist autoimmune thyroiditis. The findings clearly demonstrated an essential role for raised circulating thyroglobulin levels in maintaining the dominance of nTreg function and inhibiting thyroid autoimmunity. Subsequent identification of thyroglobulin-specific nTregs as CD4(+)CD25(+)Foxp3(+) in the early 2000s enabled the examination of probable mechanisms of nTreg function. We observed that whenever nTreg function was perturbed by immunotherapeutic measures, opportunistic autoimmune disorders invariably surfaced. This review highlights the step-wise progression of applying insights from endocrinologic and immunologic studies to advance our understanding of the clonal balance between natural regulatory and autoreactive T cells. Moreover, we focus on how tilting the balance in favor of maintaining peripheral tolerance could be achieved. Thus, murine autoimmune thyroiditis has served as a unique model capable of closely simulating natural physiologic conditions.

Effects of combinatorial in vitro stimulation with glucocorticoids and vitamin D3 on the expression of Foxp3 in CD4+ T cells of healthy individuals

Glucocorticoid (GC) resistance (GR) poses a serious clinical problem affecting a proportion of asthmatic patients. Thus the efforts aimed at exploring therapeutic methods allowing for overcoming GR are still warranted. To date, vitamin D3 was found to exert certain effects indicating that it can potentially supplement the effects of GC therapy in asthmatic patients. Here we wished to investigate whether treatment with GC and/or vitamin D3 can modulate the expression of one of crucial immunomodulatory molecules accounting for suppressive actions of natural regulatory T cells (Treg cells), namely forkhead box P3 (FoxP3). We demonstrated here that 24h in vitro stimulation with either GC or vit. D3 (alone or in combination) did not significantly affect neither frequencies of CD4+FoxP3+ T cells or the levels of expression of FoxP3 within CD4+ T cells derived from healthy individuals. Therefore we hypothesize that anti-inflammatory actions of both GC and vit. D3 do not seem to be directly related to changes in the expression of FoxP3 in CD4+ T cells.

Factors of Suppression of Immune Response in Patients with Pulmonary Tuberculosis and Eosinophilia.

We studied possible mechanisms of immunosuppression mediated by regulatory T cells that promotes suppression of antigen-specific immune response to Mycobacterium tuberculosis in patients with pulmonary tuberculosis and eosinophilia. It was shown that the number of CD4(+)CD25(+)Foxp3(+) regulatory T cells with immunosuppressive activity (Treg) increased in the peripheral blood of patients with disseminated destructive forms of pulmonary tuberculosis with multiple resistance of the causative agent to antituberculosis substances and eosinophilia. These changes were accompanied by imbalance in secretion of Treg-associated cytokines (in vitro) manifested in hyperproduction of TGFβ and IL-10 and decreased production of IL-2.