Ouabain blocks Na+/K+-ATPase and was used as positive control for blocking the transporter. The other half was incubated with solution A. Subsequent plates were washed with 1 ml/well of solution A and incubated for 5 min with 0·6 ml/well of solution A supplemented with 1 µCi/ml 86RbCl LY2835219 clinical trial (370 MBq/mg Rb). Uptake was stopped by washing the cells twice

with 1 ml/well of ice-cold rinsing solution containing the following (in mM): 140 N-methylglucamine, 1·2 MgCl2, 3 NaCl2, 10 HEPES and 0·1% BSA at pH 7·4. Solubilized cells were traced by liquid scintillation counting. All chemicals were purchased from Sigma-Aldrich and culture media and their reagents from Invitrogen. Radioactive tracers were supplied by PerkinElmer AG. Statistical analysis.  Each experimental set-up was performed three times, each conducted in sextuplet.

Data of the three experiments were taken together and analysed (n = 18). Values are expressed as mean ± standard deviation (s.d.). Optical analysis of box-plots suggested normal distribution Poziotinib cost of data. Confirmation was performed using a Shapiro–Wilk test. The effects of sevoflurane were compared with the control group (PBS group) for K+- and Na+-influx and tested by analysis of variances for repeated measurements [one-way analysis of variance (anova)], including a Tukey–Kramer multiple comparison test. Graphpad Prism4® Graphpad Instat3® (GraphPad software, La Jolla, CA, USA) was used for statistical analyses. P-values <0·05 were considered statistically significant. Animal preparation.  After approval from the local animal care and use committee (Zürich, Switzerland), experiments were performed with pathogen-free, male Wistar rats (Charles River, Sulzfeld, Germany) (body weight 350–500 g). The rats were kept in standard cages at 22°C (12-h light/12-h dark). Food

and water were supplied ad libitum. Induction of anaesthesia and monitoring was performed as described previously [26]. Rats were tracheotomized. After insertion of a sterile metal cannula, animals were ventilated in parallel (Servo Farnesyltransferase Ventilator 300, Maquet, Solna, Sweden). Pressure-controlled ventilation was set with 30 breaths per minute, pressure was 3/14 cm H2O, inspiration to expiration ratio 1 : 2 and fractional inspired oxygen concentration (FiO2) was 100%. Arterial blood was analysed at 0, 2, 4, 6 and 8 h. Using 100% FiO2 during the whole experiment, the oxygen capability of the lung is represented by the oxygen tension (PaO2 in mmHg) in arterial blood gas samples (oxygenation index: PaO2/FiO2). Body temperature was controlled by rectal temperature measurement and corrected to 37°C by a heating lamp. Experimental design.  Rats were randomized into three different groups, using sealed envelopes: (a) propofol/PBS; (b) propofol/LPS and (c) sevoflurane/LPS (n = 6 in all groups).

In summary, our study demonstrates that human DN T cells exert a strong RG7422 molecular weight suppressive activity toward CD4+ and CD8+ T cells. Moreover, we showed that human DN T cells possess a number of important biological features that highly differ from naturally occurring CD4+CD25+ Tregs. First, DN T cells exert their suppressive activity exclusively after preactivation with APCs, whereas CD4+CD25+ Tregs arise in the thymus 23. Second, human DN T cells inhibit early T-cell activation by modulating TCR-signaling,

whereas initial T-cell activation is not suppressed by CD4+CD25+ Tregs 40, 41. Third, the regulatory function of DN T cells cannot be abolished by exogenous IL-2 or CD28 engagement 41, 42. Lastly, in contrast to naturally occurring CD4+CD25+ Tregs, both resting and APC-primed DN T cells do not express Foxp3. Taken together, our results demonstrate that human DN T cells are a new subset of inducible Tregs exerting a very potent suppressive Selleckchem Small molecule library activity toward cellular immune responses. Further understanding of the mechanisms involved in human DN T-cell suppression may have important implications for novel

immunotherapies. T cells were cultured in RPMI-1640 medium (Gibco, Karlsruhe, Germany) plus 10% human AB-serum (PAN Biotech, Aidenbach, Germany). The following recombinant human cytokines were used: 800 U/mL granulocyte-macrophage colony-stimulating factor (GM-CSF; Schering-Plough, Brussels, Belgium), 500 U/mL IL-2 (Proleukin,

Novartis Pharma, Nuernberg, Germany), 500 U/mL IL-4, 5 ng/mL transforming growth factor-β1 (TGF-β; both from Tebu, Offenbach, Germany), 10 ng/mL IL-1β, 1000 U/mL IL-6, 10 ng/mL tumor necrosis factor (TNF) (all from PromoCell, Heidelberg, Germany), and 1 μg/mL prostaglandin E2 (Alexis Biochemicals, Loerrach, Germany). Preparation of TCGF was described previously 43. PBMC were separated by density gradient centrifugation (Biocoll, Biochrom, Berlin, Germany) from leukapheresis products obtained from healthy volunteers. Informed consent was provided according to the Declaration of Helsinki. CD4+, CD8+, and DN T cells were isolated from PBMC via magnetic separation according to the manufacturer’s instructions (Miltenyi Arachidonate 15-lipoxygenase Biotec, Bergisch-Gladbach, Germany). Viability and purity of the T cells were monitored by flow cytometry. CD4+CD25+ Tregs were isolated from PBMC by sorting CD4+CD25+high T cells with a MoFlo cell sorter (Beckman Coulter, Krefeld, Germany). Cells were analyzed for Foxp3 expression and used for functional assays if a purity of >95% Foxp3+ cells could be documented. Naive and memory T cells were isolated from CD4+ T cells by depletion of CD45RO+ or CD45RA+ cells using MicroBeads (Miltenyi Biotec). DC were generated from leukapheresis products as described previously 44.

(2006). Three of nine auxiliary loci ETR-B, Mtub29 and Mtub34 (Supply et al., 2006) were not included in this study because they were previously shown to be monomorphic in ST125 strains

(Valcheva et al., 2008b). The amplicons were evaluated on 1.5% standard agarose gels using a 100-bp DNA ladder (GE Healthcare). The H37Rv strain was run as an additional control of the performance of the method. Size Compound Library datasheet analysis of the PCR fragments in 1.5% agarose gels and assignment of the VNTR alleles were carried out using totallab tl100 software (Nonlinear Dynamics Ltd, UK) and by comparison with correspondence tables kindly provided by Philip Supply. Some PCR reactions were repeated and allele scoring was performed by an independent analysis by two technicians. Analysis of the IS6110 element specific for the LAM genetic family was performed as described previously (Marais et al., 2006). In brief,

a 205-bp band indicates a LAM strain due to the presence of an IS6110 element BGB324 order in a specific site in the genome, whereas a 141-bp band indicates a non-LAM strain lacking the IS6110 element in this site. To minimize the risk of laboratory cross-contamination during PCR amplification, each procedure (preparation of the PCR mixes, the addition of the DNA, the PCR amplification and the electrophoretic fractionation) was conducted in physically separated rooms. Negative controls (water) were included to control for reagent contamination. Cepharanthine NJ and UPGMA trees were built using the paup 4.0 package (Swofford, 2002) and minimum spanning tree – using the PARS program of the phylip 3.6 package (Felsenstein, 2004). At present, the mechanism of evolution of VNTR loci in M. tuberculosis

is not completely understood; for this reason, similar to other studies, VNTR alleles were treated as categorical variables, i.e. any change in a locus (gain or loss of any number of repeats) was considered equally probable. The search for historical links between the areas targeted in this work was carried out by searching Google (http://www.google.com/), Entrez Pubmed (http://www.ncbi.nlm.nih.gov/sites/entrez) and the History Cooperative (http://www.historycooperative.org/) search resources using the keywords ‘human migration,’‘tuberculosis,’‘history,’‘phylogeography,’‘coevolution’ as well as relevant geographic names used alone and in combination. This was followed by further sorting and mining of the large body of the retrieved information, and, if necessary, an additional search using more specific keywords covering bilateral relations between particular regions and countries. Although this method is neither exhaustive nor quite systematic, a quantitative approach to comprehensively study large events in human history still does not exist, to the best of our knowledge.

Our results thus provide a novel mechanistic basis reconciling previous opposite observations in the field of infections and T1D. In addition, our finding that stimulation through

TLR2 constitutes a well-suited means to expand CD4+CD25+ Tregs while ameliorating their tolerogenic function in T1D opens new possibilities for therapy of this disease and possibly other autoimmune disorders. NOD/ShiLtJ mice, and WT or TLR2−/− C57BL/6J (B6) mice were purchased from the Jackson Laboratory. C57BL/6-RIP-GP (B6 RIP-GP) transgenic mice were described previously 5, 6. For infection, a single dose of 104 PFU LCMV Armstrong 53b was given selleck kinase inhibitor intraperitoneally. Blood glucose was monitored using OneTouch Ultra system (LifeScan), and mice exhibiting values greater than 300 mg/dL were considered diabetic. Animal work in all studies was approved by the LIAI Animal Care Committee. All injections were performed intraperitoneally in 200 μL volume. Tregs, DCs, and mouse anti-mouse TLR2 mAb (Invivogen) were injected in PBS, and P3C (EMC Microcollections) was injected in DMEM (Invitrogen). Pancreas was collected and snap-frozen at the indicated time point after treatment. Frozen sections were stained with hematoxylin and eosin, and insulitis was scored blinded, as follows: (0) no insulitis, (1) peri-insulitis with no islet destruction, (2) severe peri-insulitis and some infiltrating insulitis, (3)

infiltrating insulitis MK-8669 chemical structure and some islet destruction, (4) infiltrating insulits and extensive islet destruction (or islet destroyed). Cells were stained with fluorescently labeled mAbs (BD Biosciences, eBioscience, BioLegend, Caltag) as described previously 12. Janus kinase (JAK) Samples were processed on a LSRII or FACScalibur (BD Biosciences) and results analyzed using FlowJo (Tree Star). Non-specific binding was blocked using unlabeled anti-FcγR

(BD Biosciences). Intracellular Foxp3 expression was assessed using a Foxp3 detection kit (eBioscience). For intracellular staining of cytokines, CD4+CD25+ T cells were stimulated with PMA and ionomycin (10 ng/mL and 0.5 μg/mL, respectively) or anti-CD3 (5 μg/mL) in Brefeldin A (Sigma-Aldrich) buffer prior to mAb staining. Female mice were euthanized 21 days after P3C treatment or LCMV infection, at which point virus was cleared from lymphoid tissue (data not shown). Cell suspensions were prepared from pooled spleens, mesenteric, inguinal, and pancreatic LN of 10–25 mice per group, and CD4+CD25+ T cells were purified as described previously 12. Briefly, CD4+ T cells negatively selected by magnetic separation using sheep anti-rat Dynabeads (Dynal) were stained with biotinylated anti-CD25 mAb, and CD4+CD25+ cells were purified by magnetic separation using anti-streptavidin MACS microbeads (Miltenyi Biotec). Cell purity was measured by flow cytometry and always greater than 95%.

6C). Nevertheless, splenocytes from mice injected with DCs matured with the VSGs significantly downregulated IL-17 production comparable to the T-cell cytokine profile of TNF-DC-treated animals. Mice treated with MiTat-matured DCs, however, selleck products were not able to block the nonprotective IFN-γ production as TNF-DC-treated animals, but in addition, retained high production of the disease-preventing cytokines IL-13 and IL-10 (Fig. 6C). Moreover, repetitive injections of differentially

matured DCs did not alter the frequencies of FoxP3-expressing Treg cells in spleens of EAE-diseased mice (Supporting Information Fig. 5D). This suggests that semi-mature DCs regulate EAE by protective mechanisms other than CD25+ FoxP3+ Treg-cell induction. In sum, the partial DC maturation stages were all equally effective in creating a protective Th2/Tr1-cell environment, which was able to block the Th1/Th17-cell mediated EAE. In this study, we showed that similar partial maturation stages of DCs can be achieved with the proinflammatory cytokine TNF and the T. brucei antigens selleck chemicals mfVSG and MiTat1.5 sVSG. Our data further indicate that low concentrations of pathogen-derived

TLR-mediated stimuli program DCs similarly to the inflammatory cytokine TNF for the differentiation toward an inflammatory, semi-mature DC phenotype. These partial DC maturation stages were able to induce Th2-cell priming in vitro and in vivo and induced only quantitative differences in the extent of Th2-cell differentiation. Moreover, these Th2-cell signatures did not differ in their intrinsic quality to heal autoimmune diseases such as EAE and had no influence on allergic asthma. These data have important implications for the understanding of parasitic immune

evasion, the design of vaccines and provide further insights how DC maturation signatures critically contribute to the differentiation of defined Th-cell subsets. The stimulus LPS triggers DC maturation through TLR4 ligation and directs Th-cell differentiation toward Th1-cells. Less is known which PRRs drive Th2-cell associated immune responses. Recent reports suggest that house dust mite allergens initiate asthmatic ROS1 inflammation by signaling through the TLR4 receptor complex in part by LPS contamination 45, 46. Our data show that the T. brucei antigen MiTat1.5 sVSG-conditioned DCs to produce IL-6 and IL-1β, which is dependent on TLR4 and the adaptor molecule MyD88. A novel TLR4-mediated signaling pathway was identified in which TLR4 stimuli trigger a rapid increase in intracellular cAMP followed by translocation of the transcription factor CREB and IL-6 production 47. Further investigation is needed to address whether MiTat1.5 sVSG activation of DCs is accompanied with an intracellular cAMP rise and CREB transcription factor translocation. The T. brucei AnTat1.

4E). These data indicate that the overall number of responding T cells is constant between WT and CGD, but that the inflammatory signal amplitude (i.e. IFN-γ) is increased within individual T cells in proportion to the CGD-associated increase in NO production within APCs. To directly test whether CGD APCs drive increased T-cell-dependent abscess formation in CGD, splenocytes were harvested from WT and CGD animals and depleted of both neutrophils

and T cells. The remaining cells (B cells, macrophages, and DCs; data not shown) were adoptively transferred into WT animals selleck chemical and then each animal was challenged with a seven-fold dilution of the GlyAg and SCC inoculum, which generated an abscess in 0–10% of WT animals (see Fig. 1A). We found that when WT APCs were transferred into the WT animals, 1 out of 8 mice developed an abscess, as before. In contrast, 75% of the WT animals receiving CGD APCs developed an abscess click here (Fig. 4F). These findings demonstrate that CGD APCs are sufficient to transfer the CGD phenotype characterized by increased GlyAg-induced abscess formation. Based on our findings, attenuation of NO production in the first 24 h post challenge should reduce T-cell activation and abscess incidence in CGD. We therefore performed in vitro T-cell activation experiments with CGD cells with and without the specific iNOS inhibitor 1400W.

We found that 1400W reduced the amount of IFN-γ produced by up to 50% as compared with mock-treated cultures (Fig. 5A). Next, BCKDHB WT and CGD animals were challenged with a four-fold dilution of the standard inoculum and compared with another group of CGD animals also treated 0 and 6 h post challenge with 0.5 mg 1400W. Twenty-four hours later, peritoneal lavage fluid was collected and analyzed for NO production. We found a large increase in NO production in CGD animals over

WT (Fig. 5B), reflecting increased iNOS expression (Fig. 3). In addition, 1400W did not eliminate NO production, but reduced NO levels to that seen in WT animals (Fig. 5B). Reducing NO production to WT levels in already immunocompromised CGD mice could result in the inability to clear bacterial challenge, thus we examined bacterial clearance in CGD animals treated with 1400W. Mice were challenged with 106 live B. fragilis, a leading cause of peritonitis associated with intestinal leakage 30, 31, and were treated with 0.5 mg 1400W or PBS vehicle at 0, 6, and 24 h post inoculation. All mice maintained body weight (Fig. 5C and D) and no overt change in activity levels was seen over a 10-day period. On day 8, one mouse in each group was sacrificed and blood agar plates were streaked with tissue samples of blood, liver, spleen, and peritoneal lavage and incubated under anaerobic conditions for 48 h. No bacterial growth was detected from any tissue sample from the PBS or 1400W treated mice (not shown), indicating that 1400W had no deleterious effect on the ability to clear B. fragilis.

Figure 1B shows the number of rolling leukocytes in the post-sinusoidal GDC0068 venules of mice receiving sham or endotoxin treatment, and resuscitation with either saline, AGP, or HAS. No significant differences in this parameter were observed, either between sham and LPS-treated mice receiving the same resuscitation fluid or different fluids. A different picture was found with respect to leukocyte adhesion to the post-sinusoidal venules;

as shown in Figure 1C, LPS administration, significantly elevated adherence by greater than 10-fold in saline-treated animals relative to sham. HAS treatment did not diminish this increased adherence. In contrast, mice receiving LPS and fluid resuscitation with AGP exhibited no statistically significant elevation in leukocyte adhesion in the venules compared to sham, and the number of adherent leukocytes was significantly less than in the case of the saline- or HAS-resuscitated mice. In contrast, as shown in Figure 1D, significantly increased leukocyte adhesion in the sinusoids in response to LPS and relative to sham treatments was seen in the case of all three resuscitation fluids. Sinusoidal flow (Figure 1E) was essentially unaffected by sham treatment

in saline, AGP, or HAS treatment groups, but declined L-NAME HCl significantly BMS-777607 order in response to LPS in saline and HAS-treated mice. In contrast, AGP treatment eliminated the reduction in flowing sinusoids observed with the other two resuscitation fluids. AGP elicited similar anti-inflammatory effects in the CLP model as it did in the endotoxemic mice. As shown in Figure 2B, no statistically significant differences were noted in the flux of rolling leukocytes among the four groups of mice. In contrast,

the 9.2-fold elevation of leukocyte adhesion in the saline-treated CLP mice (compared to sham-operated animals) was significantly reduced, to 4.3-fold, by AGP fluid administration, although the AGP treatment did not reduce leukocyte adherence down to baseline levels (see Figure 2C). In the sinusoids, a more pronounced anti-inflammatory effect of AGP was apparent in CLP than in endotoxemia, in that AGP resuscitation eliminated the CLP-associated increase in leukocyte adhesion that was observed relative to sham controls in the saline-treated cohort (see Figure 2D). As shown in Figure 2E, saline resuscitation failed to prevent an approximately 25% reduction in the number of flowing sinusoids in CLP versus sham-operated mice, but AGP fluid resuscitation significantly protected sinusoidal flow and eliminated CLP-associated sinusoidal blockage.

). Anti-thyroid antibodies (thyroglobulin and thyroid selleck chemical peroxidase) were analysed using a commercial ELISA kit (Orgentec Diagnostika

GmbH). Anti-neutrophil cytoplasmatic antibodies were detected by indirect immunofluorescence using ethanol/(formalin)-fixed human neutrophil slides (Inova Diagnostics, Inc.). Complement 4 (C4) levels were analysed using BN Prospec System (Dade Behring Marburg GmbH, Marburg, Germany). Human C1 inactivator levels were analysed using radial immunodiffusion (Binding Site Group Ltd, Birmingham, UK). Peripheral blood mononuclear cells (PBMCs) were isolated on Lymphoprep (Axis-Shield, Oslo, Norway). B lymphocytes were isolated by negative selection using the B cell isolation kit II for magnetic affinity cell sorting (MACS) system (Miltenyi Biotec, Bergisch Gladbach, Germany),

according to the manufacturer’s instructions, achieving >95% purity determined by flow cytometry. B cell activation phenotype was performed using three-colour flow cytometry. Freshly isolated B cells were incubated in the dark for 20 min with saturating concentrations of fluorochrome-labelled monoclonal SB203580 price antibodies. The cells were labelled with directly conjugated mouse monoclonal IgG antibody to CD19 FITC and CD27 phycoerythrin (PE)-cyanin 5 (Cy5) and directly conjugated mouse monoclonal IgG antibody to either CD21, CD40, CD86, CD69, CD5 or major histocompatibility complex class II (MHC-II) antibodies (PE, Immunotech, Beckman Coulter Co., Marseille, France). For detection of intracellular TLR-9 expression in memory

B cells, isolated B Phosphatidylinositol diacylglycerol-lyase cells were stained with anti- CD19-FITC and anti-CD27-PC5 (Immunotech). In addition, these cells were fixed and permeabilized with a cell permeabilization kit (Caltag Laboratories, An Der Grub, Austria) and stained for the detection of intracellular TLR-9 using PE-conjugated anti-TLR-9 monoclonal antibodies (R&D Systems, Minneapolis, MN, USA). Expression of these markers was carried out with a fluorescence activated cell sorter (FACS) using FC-500 software (Beckman Coulter). All markers were expressed with mean flow cytometry intensity (MFI). Results were shown as mean ± s.d. Protein phosphorylation in lymphocytes is a mechanism that controls signal transduction and protein activity and can modulate cellular proliferation, survival, differentiation, function and motility. Therefore, in order to further analyse the activation status of B cells by total phosphotyrosine, we performed Western blotting. Briefly, isolated B cells were lysed and proteins were separated by sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) and transferred to nitrocellulose extra blotting membrane (Sartorius AG, Göttingen, Germany).

5%), whereas

only one out of 27 strains isolated in Japan belonged to classical serotypes, though this strain (O142:H6) was isolated from someone who had traveled to the Philippines. The strains which were isolated in Japan were distributed in O153 and O157 serogroups. There were no common serotypes between those from Thailand and Japan. We previously Ganetespib cell line reported 5 HMA-bfpA types (34). In this study, we identified a new type, HMA-bfpA type 6 (Fig. 1). All the strains of this type were isolates from Thailand (Table 2). Most strains isolated in Japan were bfpA types 1, 4 and 5, while, those isolated in Thailand were bfpA type 2, 3 and 6. Several serotypes could be assigned to each bfpA type. The perA genes were classified as 8 HMA-types (Table 2). Most strains isolated in Japan were perA types A and B, whereas those isolated in Thailand were perA types C to H. Although perA variation was more complex than bfpA variation, each perA genotype corresponded

to a main bfpA type. Amplicons of the bfpA gene (including new HMA-type) and perA gene were sequenced. PCR amplification was performed with whole coding region primers (Table 1). Figure Palbociclib manufacturer 5 shows the phylogenetic tree of the perA sequences of our strains and those reported by Lacher et al. (29). The perA genotypes were clustered into four major groups, α, β, γ and δ, as described (29). Most of the isolates from Japan were in the β cluster. In this study, the new perA sequence types, β3.2, β3.3 and β3.4 were identified (Fig. 2). HMA typing produced similar results

to those of sequence typing in the polymorphism analysis on bfpA and perA. All except 4 strains showed autoaggregation (Table 2). Since aggregates of various sizes were observed, we defined the extent of autoaggregation according mafosfamide to 4 categories (+++ to –) (Fig. 3b). Those in category +++ (n= 30) were huge aggregates clearly visible with the naked eye, category ++ (n = 4) aggregates of medium thickness, and category + (n= 17) small, weak aggregates (Fig. 3b). Particle measurements were also carried out on the autoaggregates in each category and a different peak was observed for each one (Fig. 3a). When morphological changes were investigated by scanning electron microscopy, we observed microcolony structures at 3 hr post inoculation. Microcolonies in category +++ were intricately intertwined, whereas in category +, they were barely visible (Fig. 3c). The rate of aggregation was quantitated by measuring the turbidity with reference to the E2348/69 strain using the representative strain of each category (Fig. 3e). Significant differences were observed among categories (P < 0.02). Adherence to HEp-2 cells has been used to identify EPEC (5, 38). In this regard, LA is a qualitative adherence pattern consisting of compact microcolonies on the surface of epithelial cells.

In addition, we used calreticulin as an adjuvant, and others have demonstrated that calreticulin increases CD8 T cell responses. In conclusion, our current data demonstrate that adenoviral vectors expressing fusion proteins consisting of CRT and ESAT-6 promote a specific immune response but do not protect against TB challenge. SCEG received a PhD scholarship from the National Council of Science and Technology (CONACYT) of México. This work was supported in part by a grant to RMDOL from PAICYT, UANL and CONACYT of https://www.selleckchem.com/products/NVP-AUY922.html México. Funding for the mouse studies research was provided by

NIH, NIAID NO1-AI-40091. “
“An adequate effector response against pathogens and its subsequent inactivation after pathogen clearance are critical for the maintenance of immune homeostasis. This process involves an initial phase of T-cell effector (Teff) activation followed by the expansion of regulatory T cells buy PF-02341066 (Tregs), a unique cell population that limits Teff functions. However, significant questions remain unanswered about the mechanisms that regulate the balance between these cell populations. Using an in vitro system to mimic T-cell activation in human peripheral blood mononuclear cells (PBMC), we analysed the patterns of Treg and Teff activation, with special attention

to the role of type I interferon (IFN-I). Interestingly, we found that IFN-α, either exogenously added or endogenously induced, suppressed the generation of CD4+ FoxP3HI IFN-γNeg activated Tregs (aTregs) while simultaneously promoting propagation of CD4+ FoxP3Low/Neg IFN-γPos activated Teffs (aTeffs). We also showed that IFN-α-mediated inhibition of interleukin (IL)-2 production may play an essential role in IFN-α-induced

suppression of aTregs. In order to test our findings in a disease state with chronically elevated IFN-α, we investigated systemic lupus erythematosus (SLE). Plasma from patients with SLE was found to contain IFN-I activity that suppressed aTreg generation. Furthermore, anti-CD3 activated SLE PBMCs exhibited preferential expansion of aTeffs with a very limited increase in aTreg numbers. TCL Together, these observations support a model whereby a transient production of IFN-α (such as is seen in an early antiviral response) may promote CD4 effector functions by delaying aTreg generation, but a chronic elevation of IFN-α may tip the aTeff:aTreg balance towards aTeffs and autoimmunity. Regulatory T cells (Tregs) are a distinct thymically derived or inducible subset of T cells with unique abilities to suppress immune responses and to maintain immunological unresponsiveness to self-antigens.1 The absence of Tregs in knock-out or antibody depletion mouse models leads to systemic autoimmunity.