2) PD-1/PD

2). Selleckchem Bioactive Compound Library Both surface expression measurement as well as real-time analysis of lung-derived CD11c+MHC class II+ DC confirmed the presence of various FcγR and revealed high RNA-levels of FcγRII and readily detectable mRNA of FcγRI and FcγRIII (Fig. 2). Similarly, all splenic DC subpopulations showed expression of the FcγR tested, with CD4−CD8− DC having slightly lower expression of FcγRI (Fig. 2A). Pulmonary macrophages expressed all tested FcγR on their surface (Fig. 2E). We hypothesized that increased antigen uptake by DC through FcγR could potentially lead to increased MHC class II-mediated T-cell proliferation, thereby facilitating allergic airway inflammation.

To compare whether OVA and anti-OVA IgG immune complexes (OVA-IC) influences antigen presentation by DC subsets in vitro, OVA and anti-OVA IgG were mixed at increasing ratios (from 4:1 to 1:4) and IC-formation confirmed using gel electrophoresis and mass spectrometry (data not shown). A ratio of 1:4 (OVA:anti-OVA IgG) led to readily detectable OVA-IC.

Hence, we used 25 μg/mL OVA or the same amount of OVA in immune-complexed form (OVA:anti-OVA IgG, 1:4) to pulse sorted spleen-derived DC subsets. The cells Ponatinib were then co-cultured with CFSE-labeled OT-II cells and antigen presentation was assessed by measuring T-cell proliferation, visualized as a progressive dilution of the CFSE fluorescent marker. CD4+CD8− DC and CD8−CD4− DC, but not CD8+CD4− DC, led to significantly increased T-cell proliferation

when pulsed with OVA-IC, as compared to OVA alone. This effect was completely abrogated when DC deficient for FcR γ-chain where used indicating the specificity of this effect (Fig. 3A and B). Similarly, experiments using low-endotoxin OVA (EndoGrade™ OVA) in combination with anti-OVA IgG revealed significantly augmented T-cell stimulation by splenic DC. Alternatively, splenic DC from TLR4-deficient Morin Hydrate mice likewise led to a highly significant increase in T-cell proliferation when pulsed with OVA-IC as compared to OVA alone, suggesting no considerable contribution of LPS-contamination of OVA (data not shown). In order to better define the relevance of our observation for allergic airway hyperresponsiveness, we then purified CD11c+MHCII+ DC from the lungs of the respective mice, pulsed the cells with OVA or IC and then used them to stimulate CFSE-labeled OT-II cells. Again, T-cell proliferation doubled when using lung DC from B6 mice, in a manner similar to splenic DC, but no such effect was observed when FcγR-deficient lung DC were used (Fig. 3A). Exposure of sorted CD11c+MHCII+ lung DC to OVA-IC led to IL-6 and TNF-α secretion (Fig. 3C) and up-regulation of the co-stimulatory molecule CD86 on BM-derived DC (BMDC) (Fig. 3D).

Plates blocked with PBS containing 10% FBS before 50 μL supernata

Plates blocked with PBS containing 10% FBS before 50 μL supernatants were added, and the incubated overnight at 4°C. After extensive washing, plates were incubated with a biotinylated anti-IFN-γ detection antibody. Plates were developed using avidin-peroxidase and 2-2′-azino-bis(3-ethyl-benzthiazoline-6-sulfonic acid) substrate (Sigma-Aldrich). OD405 was measured, and cytokine levels determined against a recombinant protein standard. All antibodies were purchased form BD Pharmingen. IFN-γ–producing cells were enumerated from splenocyte

Kinase Inhibitor Library mouse populations isolated from immunized mice by cellular ELISPOT assay 47. Briefly, splenocytes (5×106 cells/mL) were cultured for 48 h in 24-well plates either with B5, B1 (10 μg/mL) or medium alone. Millititer HA nitrocellulose plates (Millipore) were coated overnight at 4°C with anti–IFN-γ. After blocking coated plates, antigen-stimulated cells were added at graded concentrations for 24 h at 37°C. Atezolizumab The wells were then incubated with biotin-conjugated anti–IFN-γmAb followed by incubation with avidin peroxidase (Vector Laboratories). Spots were developed by the addition of 3-amino-9-ethylcarbazole substrate (Sigma-Aldrich) and counted using a computerized image analysis system (Ligh-tools Research) and the image analyzer program, NIH Image 1.61. Immature BM-derived DC (1×106) were pulsed with 1×106 apoptotic (Ap-T) or untreated (T) T cells, peptide (20 μg/mL) or PBS for 8–12 h. In most experiments

DC were enriched by positive selection using anti-CD11c microbeads (Miltenyi) 3-mercaptopyruvate sulfurtransferase and treated with activation modulators (for example, LPS (Sigma)) for 4–12 h CD11c+. DC were disabled (irradiated (3000 rad) or glutaraldehyde-fixed) and incubated with T responder cells (2×104/well) for the duration of the assay at 37°C in 5% CO2. For experiments analyzing the effect of antigen processing/presentation blockade, inhibitors

were first added to BM-derived DC for duration of 2 h – Concanamycin A (10–100 nM). DC were then washed and pulsed with peptide or apoptotic T cells for a total of 8 h (the final 4 h in the presence of LPS (1 μg/mL)). DC were positively selected using anti-CD11c microbeads (Miltenyi), and glutaraldehyde-fixed, before co-culturing with responder T cells. For IFN-γ secretion analysis, supernatants were harvested at 48 h. T-cell proliferation was measured by 3H-thymidine incorporation at 72 h. The desired number T cells were incubated in complete medium 4–12 h at 37°C in 5% CO2 in the presence of 5 μg/ml anti-Fas antibody (BD Pharmingen). To determine apoptosis induction 1×105 T cells in 100 μL buffer were stained with 10 μL/mL Annexin V FITC (BD Pharmingen). By flow cytometry apoptosis induction was confirmed using two parameters: (i) an anti-clockwise shift of the T-cell population in the forward versus side scatter dot plot, and (ii) a significant right shift of the peak on the FL1 histogram axis – indicating Annexin V staining.

[25, 26] Candida spp , especially C albicans, are able to produc

[25, 26] Candida spp., especially C. albicans, are able to produce and secrete various hydrolytic enzymes, particularly proteinases, lipases and phospholipases.[21] Shimizu et al. [27] and Abu-Elteen et al. [28] demonstrated the relevance of proteinases, hyaluronidases, condroitinases and phospholipases as virulence–related factors, reporting that secretory strains of Candida spp. showed an increased ability to invade tissues compared to non-secretory strains. According to Costa et al. [29], the activity of

proteinases and phospholipases is directly related to the promotion and establishment of infection. According to studies by Noumi et al. [30], hydrolytic enzymes and adhesins produced by C. albicans present themselves as the largest factor check details associated with virulence, a fact previously suggested by Neugnot et al. [31]. Secreted aspartic proteinase (Sap) was first described in 1965 and was named Candida acid proteinase due to its optimal activity at acidic pH ranges and

because it was primarily found in yeast of the genus Candida.[32, 33] Sap may be considered www.selleckchem.com/products/Adrucil(Fluorouracil).html the most important hydrolytic enzyme among the virulence-associated factors of Candida spp.[34] Saps are believed to contribute to the adhesion and invasion of host tissues through the degradation or distortion of cell surface structures or the destruction of cells and molecules of the immune system, to avoid or resist microbicidal attack.[35, 36] Saps have a broad substrate specificity and are able to degrade a variety of human proteins such as albumin, haemoglobin, keratin, collagen, laminin, fibronectin, mucin and almost all immunoglobulins, including immunoglobulin A, which is resistant to the majority of bacterial proteinases.[37]

Basically, these enzymes are involved in the digestion of proteins by providing nitrogen to aid the survival of fungal cells.[38] At first glance, they appear to be acquiring nutrients; however, Saps may have developed other functions related to virulence such as degrading structural proteins Acesulfame Potassium and proteins of the immune system.[20, 21] In C. albicans, the production of Sap is encoded by a family of 10 SAP genes that are grouped into six subgroups or subfamilies: SAP1-3, SAP4-6, SAP7, SAP8, SAP9 and SAP10.[39-41] Gene transcription generates isoenzymes, named due to conformational and structural similarities among them.[40, 41] Sap1–Sap3 share 67% genetic identity and Sap4–Sap6 share as much as 89% identity. Sap1–Sap3 and Sap4–Sap6 are closely clustered. Sap7 only shares 20–27% identity with the other Sap proteins and is externally positioned. Sap8 is related to the clusters formed by Sap1–Sap3 and Sap4–Sap6. Sap9 and Sap10 differ from the other Sap1–8 isoenzymes and constitute a distinct group (Fig. 1).[42-44] All members of the family of Sap proteins possess four cysteine residues and two conserved aspartate residues.

Microglia are unique among the major cell types of the central ne

Microglia are unique among the major cell types of the central nervous system (CNS) in being not derived from the neuroectoderm. Ultimately derived from myeloid precursors, they are representatives of the monocyte/macrophage series of cells, and can be regarded as the resident cells of the innate immune system in the CNS. ‘Neuroinflammation’, in the form of activation Selleck GS-1101 of microglia, is an almost ubiquitous feature of diseases of the CNS. Is neuroinflammation simply a reaction to tissue damage and disease or, alternatively, is it an integral component of CNS disease,

promoting neuronal and synaptic damage and important in pathogenesis? Consideration of organs other than the brain certainly tells us that chronic inflammation is harmful, causing tissue damage and fibrosis. Examples include inflammation of synovial joints resulting in arthropathy and damaging chronic inflammation of the liver, pancreas, gastrointestinal tract and lungs. Early proponents of the concept that neuroinflammation

is important in the pathogenesis of neurodegenerative diseases such as Alzheimer’s disease (AD) include Griffin and McGeer in the 1980s. Initially, such views were controversial and met with considerable scepticism but in subsequent years, as new evidence emerged, the role selleck compound of neuroinflammation in AD has been given serious consideration by many others. An important stage was in the 1990s when epidemiological studies of use of non-steroidal anti-inflammatory drugs began to provide evidence of a role for neuroinflammation in the pathogenesis of AD. More recently, this concept has been given

further support by genome-wide association studies of AD demonstrating that variation in genes encoding several inflammation-related proteins influences risk of AD development. In this special issue of Neuropathology and Applied Neurobiology, we are privileged to have reviews written by international leaders in the field of neuroinflammation to provide an update and new insights into the role of microglial activation in ageing and in neurodegenerative disease. In the first review, we set the scene in describing how in the normal however CNS microglia appear quiescent and downregulated, and how they become activated in disease states. Evidence mainly from in vitro and rodent studies indicates that microglia can exist in different activation states, prompted by different stimuli and with different functional consequences. We discuss to what extent these different activation states can be identified in the human brain, and raise the question as to whether manipulation of the microglial state of activation may in future be of therapeutic use. In the second review, Diana Norden and Jonathan Godbout discuss evidence of alterations of microglia in the ageing process, rendering them primed or sensitized to react to stimuli and with the balance of cytokine expression biased towards a pro-inflammatory state.

5, containing 1 19 mg/mL 5-Bromo-4-chloro-3-indolyl phosphate (BC

5, containing 1.19 mg/mL 5-Bromo-4-chloro-3-indolyl phosphate (BCIP, Sigma), 0,4 mg/mL Nitro

blue tetrazolium (NBT, Sigma) and 0.24 mg/mL levamisole (Sigma). The reaction was stopped by 15 minutes of incubation in 1 mM Tris-Hcl, 0.1 mM EDTA, pH 8. Sections were finally mounted in Permount (Fisher Scientific) and observed by light microscopy. The specific antibodies used were, three MABs (40E2, 40E10, 41B12), which were used as supernatant culture. The polyclonal antibody against penaeidin (25) was used at a concentration of 3 μg/mL of Tris buffer. The WSSV detection kit (DiagXotics) was used according to manufacturer’s instructions. Although some shrimp exhibited an initial WSSV infection, the number and level of shrimp displaying selleck WSD lesions

increased after induced infection from an index of 0.15 ± 0.66 to 1.3 ± 0.50 (24). The animals used to perform this study were selected on the basis of presence of LOS in the LO (24). Following the classification made by Hasson et al. (7), before infection the main type were A LOS, but after 24 hr the number of LOS increased and B LOS appeared, and 72 hr after infection B LOS were the total LOS type (100%). These animals exhibited in addition an increase of infiltrated hemocytes in tissues (24). Immunostaining with the five Cabozantinib solubility dmso antibodies used in this study was observed in the LO. Signals of hemocytes were detected in the lumen and stromal matrix of tubules as well as in hemal sinuses. Immunostaining Olopatadine also showed hemocyte degranulation in the stromal matrix and the tubule walls. Concerning LOS, we detected immunolabeling restricted to cytoplasmic vesicles with MABs 40E10, 41B12 and antipeneidin antibody. Positive staining for WSSV was observed in infected cells, in the outer tubule walls and vesicles of some LOS (Table 1 and 2). Before WSSV infection, the immunolabeling

was restricted to some infected cells of the epithelium and tegumental glands, but no immunolabeling was detected, either in the LO or LOS (Table 1). After the infection, the antibody against WSSV labeled the infected cells in several tissues, mainly epithelium and connective tissue. In the lymphoid organ this antibody strongly labeled the outer wall of tubules and some vesicles in the spheroids (Fig. 1a,b). Before the induced infection, staining for SGH was observed in some tubules of LO, and a well defined labeling of exocyted α2-macroglobulin was detected in the external stromal matrix with the MAB 41B12 (Table 1). After the induced infection, strong staining for SGH, and degranulated material was detected in the internal and external stromal matrix of tubules with the MAB 40E10 (Fig. 2a). LGH immunostained with the 40E2 MAB were mainly presented in the lumen, stromal matrix and hemal sinuses of LO. A low labeling was also observed in the fibrous material of outer tubule walls of LO (Fig. 2b).

Initiation of dialysis in patients with RIFLE F and AKIN 3 should

Initiation of dialysis in patients with RIFLE F and AKIN 3 should always be considered. “
“Aim:  The clinical course and outcome of patients with haemorrhagic fever with renal syndrome (HFRS) caused by Puumala (PUUV) and Dobrava viruses (DOBV) were analyzed and

whether it left long-term consequences on kidney function after 10 years was evaluated. Methods:  Cross-sectional studies were conducted to test the kidney function and blood pressure of HFRS-affected patients and to follow them up 10 years after. Eighty-two PUUV- and 53 DOBV-induced HFRS patients and 14 and 31 participants 10 years after having contracted PUUV- and DOBV-related diseases, respectively were evaluated. Results:  PLX-4720 ic50 Serum creatinine concentrations were 279.5 and 410 mcmol/L in PUUV and DOBV groups, respectively (P = 0.005). There were six and 13 anuric (P < 0.05), none and seven dialysis-dependant (P < 0.05), and nine and 18 hypotensive patients (P < 0.05) in PUUV and DOBV groups, respectively. After 10 years, glomerular filtration rates were 122.1 ± 11.1 and 104.7 ± 20.2 mL/min (P < 0.05) in PUUV and DOBV groups, respectively. Conclusion:  During the acute phase, DOBV causes more severe renal impairment than PUUV infection. After 10 years follow up, renal function was found within normal limits, although after DOBV infection glomerular

filtration rate (GFR) was significantly lower than after PUUV infection. “
“Haemoglobin this website (Hb) variability is associated with poor survival in patients with chronic kidney disease. Association of Hb variability after kidney transplantation with patients’ and graft survival has not been adequetly studied. This retrospective study used registry data to examine the association Vitamin B12 between Hb variability in the early post-transplant period (first 6 months) and graft survival after kidney transplantatin. Kaplan–Meier and Cox regression analyses were used for univariate and multivariate associations between mortality, death censored graft survival

and the composite outcome of both, in 752 patients after kidney transplantation. Hb values were collected each month during the first 6 months after transplantation, and Hb variavility was calculated using the residual standard deviation method. The highest quartile of Hb variability was associated with inferior graft and patients’ survival in univariate (hazard ratio (HR) 2.18; 95% confidence interval (CI) 1.51 to 3.13; P < 0.001) and multivariate models (HR 1.5; 95% CI 1.029 to 2.18; P = 0.035). This association was mainly due to increased death censored graft failure in the high variability group (HR 2.75; 95% CI 1.73 to 4.38; P < 0.001) and (HR 1.67; 95% CI 1.023 to 2.74; P = 0.04) in the univariate and multivariate models, respectively. There was no association between Hb variability and the risk of death (HR 1.51; 95% CI 0.88 to 2.57; P = 0.132).

Both of these hospitals are major central referral centers to whi

Both of these hospitals are major central referral centers to which many patients from other areas of Iran are referred. In all, 183 immunocompromised patients were included in this study. Eligibility criteria NVP-BGJ398 were immunosuppression

due to HIV infection (with decreased white cell counts), hematological malignancies and use of immunosuppressive drugs after solid organ transplant or for treatment of chronic or intractable hematologic diseases. The ethics committee of Baqiyatallah University of Medical Sciences approved the study protocol. After informed written consent had been obtained, the study nurse administered a comprehensive questionnaire to each patient. This author-compiled checklist included items on patient variables including age, sex and weight; sociodemographic and intra-familial factors; location of dwelling; occupation; number of household members with diarrhea; zoonotic factors including exposure to pets and farm animals; and environmental factors including source of drinking water and exposure AZD8055 in vitro to lake, river or swimming pools. Clinical characteristics including diarrhea, weight loss, vomiting, abdominal pain and nausea, presence of concomitant microbial infections, antiretroviral use and laboratory characteristics including CD4 + T-cell counts were recorded. This checklist was filled out

by a physician who confirmed patient’s symptoms by physical examination and so on. Diarrhea was defined as three or more watery or loose stools in a 24-hour period. Diarrhea that persisted for more than two weeks was considered chronic; otherwise, it was classified as acute. Weight loss was considered significant when referred patients lost more than 10% of their baseline body weight during their hospitalization. Three fecal samples were collected at two days intervals from each patient and placed in a disposable plastic cup. The samples were taken immediately to the laboratory and stored at −20°C until analysis. The fecal specimens were concentrated using a sucrose solution with a specific gravity of 1.200 at a centrifuge speed of 800

×g for 10 mins. All samples were stained by the modified Ziehl-Neelsen method and examined under Metalloexopeptidase bright field microscopy. A sample was considered Cryptosporidium positive if typical oocysts 4–6 μm in diameter were visible. Fecal samples were subjected to six cycles of freeze–thaw in liquid nitrogen and a 95°C water bath to rupture the oocysts. DNA was isolated from aliquots of frozen stool using the QIAamp DNA stool minikit (Qiagen, Gaithersburg, MD, USA) according to the manufacturer’s instructions. A two-step nested PCR protocol was used to amplify the 18S rRNA gene (830 bp). The fragment of the 18S rRNA gene was amplified by PCR using the following primers: 5′-TTCTAGAGCTAATACATGCG-3′ and 5′-CCCATTTCCTTCGAAACAGGA-3′ for primary PCR and 5′-GGAAGGGTTGTATTTATTAGATAAAG-3′ and 5′-AAGGAGTAAGGAACAACCTCCA-3′ for secondary PCR.

Indirect allorecognition (i e involving recipient APCs) and dire

Indirect allorecognition (i.e. involving recipient APCs) and direct allorecognition (i.e. involving donor APCs) occur in chronic and acute rejection, respectively 15. Thus, to analyze allograft-derived donor APCs in acute rejection process, we transplanted WT and CalpTG skin allografts onto BALB/C mice and examined the skin allograft survival. The survival of the C57BL/6 skin allograft was not affected by the presence of the transgene under these conditions (10 d for allografts derived from both WT and CalpTG donors;

n=5 and 6, respectively). To further assess whether the defective recruitment of T cells in CalpTG recipients was explained by a direct effect of calpastatin transgene in T cells, we transplanted BALB/C skin allografts onto recipient mice lacking T cells (RAG-1−/− mice) and reconstituted

with either WT or CalpTG spleen lymphocytes. At EPZ-6438 price day 8, allograft infiltration by CD3+ cells was significantly reduced after adoptive transfer of lymphocytes from CalpTG as compared with WT mice (59.6±15.0 versus 508.8±102.6 cells/high power field (HPF); n=4; p<0.004). Thus, calpastatin transgene expression in lymphocytes is sufficient to limit markedly GDC-0973 research buy skin allograft infiltration by these cells. Prior to gain insight onto how calpastatin transgene might affect T-cell recruitment, we verified the ability of calpastatin transgene to limit calpain activity in T cells. As assessed by measuring the calpain-specific cleavage of fluorescent 7-Amino-4-methylcoumarin (AMC) (Fig. 3A) and by measuring the 145/150-kDa spectrin BDP expression by Western Phospholipase D1 blotting (Fig. 3B), calpastatin excess had no effect on calpain activity in resting T cells, but limited TCR-dependent calpain activation in

T cells exposed to αCD3 mAb. These data are consistent with a model in which calpains and calpastatin are not co-localized within the cell at rest. Calpastatin diffusion after calcium-related cell stimulation allows calpastatin to interact with calpains, thereby modulating its activity 13. Given that the calpain activity is involved in the activation of NF-κB and NFATc1 6, 9, two pathways leading to the generation of effector T cells 16, the nuclear expression of these transcription factors was also determined in T cells from WT and CalpTG. As shown in Fig. 3C and D, αCD3 mAb-induced nuclear translocation of NF-κB and NFATc1 was not modified by calpastatin transgene expression. These data suggest that the activation of NF-κB and NFATc1 is not essential for the control of T-cell recruitment by calpastatin transgene. Failure of T-cell recruitment into skin allograft is potentially explained by sequestration of circulating T cells into secondary lymphoid tissues and/or impairment in T-cell adhesion, migration and proliferation. We first determined by flow cytometry the number of CD3+ cells in spleen and graft-draining lymph nodes, 8 days after skin transplantation.

Bcl6 can efficiently repress the expression of Blimp-1 and subseq

Bcl6 can efficiently repress the expression of Blimp-1 and subsequent plasma cell differentiation ([8, 54, 61, 62], J. Alinikula, K.-P. Nera, S. Junttila and O. Lassila, unpublished

observations). The repression can occur directly by interfering with the function of Blimp-1-inducing STAT3 [62] and independently by binding to Blimp-1 intronic sequences [61, 63]. Additionally, Bcl6 may repress Blimp-1 via regulating the other repressors of Blimp-1, such as Bach2 (J. Alinikula, K.-P. Nera, S. Junttila and O. Lassila unpublished observations). Thus, the function of Bcl6 is to prevent the Selleckchem ABT888 premature differentiation of plasma cells to allow effective Ig SHM and CSR during the GC response (Fig. 3). In addition to inducing the activators of plasma cell differentiation, the repressors of plasma cell differentiation Pax5, MITF, Bach2 and Bcl6 [8, 28, 61, 62, 64, 65] need to be suppressed (Fig. 3). The downregulation of Pax5, a central factor for the commitment and maintenance of B cell phenotype [66], is crucial for the plasma cell differentiation [9]. Pax5 expression can efficiently prevent the differentiation of antibody-secreting plasma cells and the expression of Blimp-1 [9, 28, 67–69]. Pax5 also represses

the expression of Z-IETD-FMK manufacturer several genes associated with immunoglobulin secretion, such as Ig J-chain [70–72] and Xbp1 [8, 9, 35], and inhibits high-level transcription of Ig loci [73]. Inactivation of Pax5 gene in DT40 B cells induces plasma cell transcription programme and Ig secretion [8]. Conditional inactivation of Pax5 in mature B cells induces also a similar phenotype [28]. The downregulation of Pax5 is one of the initiating mechanisms of plasma cell differentiation in GCs. The evidence for this

comes from the experiments where Blimp-1 gene was engineered to harbour a GFP reporter gene [20]. This model was used to discover a population of GC cells called preplasmablasts that have downregulated the expression of Pax5 but not yet induced the expression of Blimp-1 [27] suggesting that B cell properties Tenoxicam are not lost only after the induction of Blimp-1 but rather precede the Blimp-1 expression. Pax5 can also directly repress the Blimp-1 expression [67]. In line with these results, inactivation of Pax5 in DT40 cells leads to spontaneous differentiation to plasma cells [8]. The mechanism for physiological suppression of Pax5 expression in GCs is however currently unknown. The Pax5-deficient DT40 cells have, however, also lost their Bcl6 expression [8] warranting the possibility that Pax5 deletion induces plasma cell differentiation via upregulation of Blimp-1 after losing Bcl6-mediated Blimp-1 repression. Indeed, Bcl6 expression in Pax5 deficient cells can repress Blimp-1 [8], but not vice versa: enforced Pax5 expression in Bcl6-deficient cells cannot repress Blimp-1 (J. Alinikula, K.-P. Nera, S. Junttila and O.

In this review we will discuss evidence

In this review we will discuss evidence selleck monoclonal humanized antibody from both animal models and patients suggesting that Treg therapy would be beneficial in the context of inflammatory bowel disease (IBD). We will examine the role of T-cell versus Treg dysfunction in IBD and discuss the putative antigens that could be potential targets of antigen-directed Treg therapy. Finally, the challenges

of using Treg therapy in IBD will be discussed, with a specific emphasis on the role that the microbiota may play in the outcome of this treatment. As Treg therapy becomes a bedside reality in the field of transplantation, there is great hope that it will soon also be deployed in the setting of IBD and ultimately prove more effective than see more the current non-specific immunosuppressive therapies. T regulatory cells (Tregs) play a critical role in maintaining immune homeostasis and limiting autoimmune responses by modulating cells of both the innate and adaptive immune systems. Considered the primary mediators of peripheral tolerance, Tregs regulate self-reactive lymphocytes via a number of mechanisms including secretion of inhibitory cytokines such as interleukin-10 (IL-10) and transforming growth factor-β (TGF-β), granzyme-mediated cytolysis, CTLA-4 expression, metabolic disruption and dendritic cell targeting (reviewed in refs. 1–3). Classically defined Tregs are found within the CD4+ T-cell pool and are identified

by their constitutive expression of FoxP3, and, often, the IL-2 receptor α-chain (CD25).4 Numerous studies have shown that FoxP3-expressing Tregs can be divided into two distinct subsets: naturally occurring Tregs (nTregs) which develop in the thymus via central tolerance mechanisms and peripherally induced Tregs (iTregs) which differentiate from naive T cells when self or non-self antigen is encountered in the periphery under tolerogenic conditions.5,6 A third distinct subset of Tregs, referred to as type 1 regulatory (Tr1) cells, do not constitutively express

FoxP3 and are induced in the periphery in the presence of IL-10 and/or specialized subsets Fludarabine cell line of antigen-presenting cells.7 In contrast to FoxP3+ Tregs, there is currently no known lineage-defining transcription factor for Tr1 cells, and they are identified solely on the basis of their cytokine production profile (IL-10+ IL-4− interferon-γlow) as well as their IL-10-dependent suppression of immune responses.7 Because of their potent, antigen-specific suppressive capacity, both FoxP3+ Tregs and Tr1 cells may be promising candidates for immune therapy in a variety of chronic inflammatory diseases, including inflammatory bowel disease (IBD). The hope is that boosting this natural mechanism of tolerance will offer a replacement for the broad-spectrum immunosuppressive drugs that are often ineffective and carry the risk of promoting cancer or infections. Pioneering studies by Powrie et al.