In the present study, we confirm these observations using IDO-KO mice and show that the suppression of AHR and specific IgE induced

by SIT treatment in wild-type mice is absent in IDO-KO mice. Apparently, loss of IDO changes the sensitivity to SIT-mediated suppression of asthmatic manifestations, but remains sensitive to the adjuvant effect of CTLA-4–Ig as CTLA-4–Ig co-administration restores the suppression of AHR and OVA-specific IgE responses in IDO-KO mice to the level observed in wild-type mice. The adjuvant effect of CTLA-4–Ig might also utilize other tolerogenic mechanisms such as activation of members of the forkhead https://www.selleckchem.com/products/rxdx-106-cep-40783.html box O (FoxO) family of transcription factors, or induction of nitric oxide synthesis

by so-called reverse signalling in DCs through B7 molecules. Interestingly, FoxO has been implicated in tolerance induction and it has been shown that CTLA-4–Ig induces tolerogenic effects by activating FoxO in DCs learn more [32, 36]. Moreover, it has been observed that induction of allograft tolerance by CTLA-4–Ig is dependent upon both IDO and nitric oxide [37]. More studies are needed to unravel the role of other pathways induced by reverse signalling in the adjuvant effect of CTLA-4–Ig towards SIT. Although we cannot yet exclude all reverse signalling pathways, it appears very likely that CTLA-4–Ig acts by blocking CD28-mediated T cell co-stimulation during SIT treatment. Antigen presentation in the absence of proper co-stimulation leads to T cell anergy or induction of inducible regulatory T cells (iTreg cells) [38]. Because we found that CTLA-4–Ig co-administration suppresses the frequency of both CD4+CD25+FoxP3+ Treg and CD4+ST2+ Th2 cells in blood, we speculate that the augmented suppression induced by CTLA-4–Ig is mediated by a FoxP3-negative Treg cell subset or the direct induction of anergy in Th2 cells. Alternatively, the reduced percentage of CD4+CD25+FoxP3+ T cells in the blood could be due to migration of these cells to the lymph

nodes, as has been seen in venom SIT in human [39]. After inhalation challenges, when SIT-induced tolerance suppresses the manifestation of experimental asthma, we observed no increased production Amobarbital of TGF-β or IL-10. In fact, at this time-point, we observed suppression of both Th1 (IFN-γ) and Th2 (IL-4, IL-5) cytokines in the lung tissue. This may indicate that co-administration of CTLA-4–Ig with SIT leads to an increased function of Treg cells which are capable of suppressing both Th1 and Th2 cell activity. Such an enhanced Treg cell function, however, appears to be independent of the production of the immunoregulatory cytokines TGF-β or IL-10, as their levels were not elevated. An alternative mode of action might entail suppression of Th1 and Th2 effector cells mediated by direct cell–cell contact [40].

3b) in terms of a low production of IL-4

and IL-5 and high secretion of IL-10. No correlation was observed for Aloxistatin mouse the individual donors between the levels of response to TG and TT (data not shown), indicating that the variability observed was restricted to TG, as the challenging antigen. To identify the source of IL-10 on day 1, PBMC were coated with bi-specific anti-CD45/anti-IL-10 beads before antigen stimulation to capture secreted cytokine at the cell surface. The CD4+ T cells and CD14-expressing monocytes were then examined by flow cytometry for the presence of released IL-10. Upon stimulation with TG, low IL-10 staining of most monocytes, indicated by a right shift of the cell profile, was consistently observed (Fig. 4a). On the other hand, IL-10 capture by CD4+ T cells was minimal (< 10 IL-10-bearing cells per 10 000 CD4+ T cells, Fig. 4b), consistent with a clonal response to the antigen. Counterstaining for memory and naive T cells, with anti-CD45RO

and anti-CD45RA, respectively, revealed that TG induced IL-10 production in a significant proportion of CD4+ memory T cells (3·1 ± 1·7 per 10 000 CD4+ T cells, P < 0·01, MLN0128 Fig. 4c), whereas the numbers of cells producing IL-10 in response to TT and KLH were non-significant (0·38 ± 0·52 and 0·52 ± 0·43 cells per 10 000 CD4+ T cells, respectively). The corresponding numbers of naive CD4+ T cells producing IL-10 upon stimulation with TG, TT and KLH were 1·1 ± 0·61, 0·21 ± 0·37 and 1·8 ± 1·1 cells per 10 000 CD4+ T cells, respectively (Fig. 4d), and, as such, were non-significant. To address the question Farnesyltransferase of whether TG-specific memory T cells were orchestrating the monocyte IL-10 response to TG, PBMC were depleted of CD3+ T cells or CD14+ monocytes (as appropriate control) and then stimulated with

either TG or TT. The IL-10 and TNF-α responses were examined at day 1 after stimulation. Depletion with the anti-CD3 beads removed 99·2 ± 0·4% of the T cells from the PBMC with quantitative recovery (116 ± 20%) of the monocytes, while CD14 depletion almost completely removed the monocytes (98·7 ± 2·4%), with a non-significant reduction (43·5 ± 22·5%) in the size of the T-cell population. Monocyte depletion abrogated TNF-α production, following TG stimulation, and markedly diminished (though only with borderline significance, P < 0·06) TNF-α secretion in response to TT (Fig. 5a). By contrast, T-cell depletion resulted in only non-significant reductions in TNF-α production upon stimulation with either antigen (Fig. 5a). Similarly, virtual ablation of IL-10 synthesis was observed upon CD14+ cell depletion, irrespective of the challenging antigen (Fig. 5b), confirming that monocytes were primarily responsible for this cytokine’s production on day 1. On the other hand, the effect of T-cell depletion on IL-10 production differed markedly for the two antigens. While TG-stimulated secretion of IL-10 was drastically reduced (P < 0·002) (Fig.

A large numbers of endocrine cells are dispersed among the epithelial click here cells of gut mucosa and react to changes in gut contents by releasing hormones that are, in general, targeted to other parts of the digestive system [1]. There are at least 14 different populations of enteric endocrine cells scattered throughout GI epithelia [2]. Enteric endocrine cells release various biologically active compounds such as gastrin, secretin, stomatostatin, cholecystokinin, chromogranins (Cgs) and serotonin (5-hydroxytryptamine: 5-HT) [3–5]. The hormones released from the enteric endocrine cells are important enteric mucosal signalling

molecules influencing gut physiology (motor and secretory function). Alteration of endocrine cell function, particularly in the context of 5-HT, has been shown to be associated in a number of GI diseases including inflammatory bowel disease (IBD), coeliac

disease, enteric infections, colon carcinoma and functional https://www.selleckchem.com/products/gsk1120212-jtp-74057.html disorders such as irritable bowel syndrome (IBS) [6–14]. The association between alteration in the production of gut hormones from enteric endocrine cells and various GI diseases emphasizes highly the significance of these hormones in intestinal homeostasis. Due to the strategic location of enteric endocrine cells in gut mucosa, interaction between immune and endocrine systems is very likely to play an important role in immune activation in relation to gut pathology and pathophysiology in various GI disorders, including IBD. This paper reviews information on the role of two major hormones of the GI tract, namely 5-HT and Cgs, in immune activation in the context of gut inflammation and highlights its implications in understanding the pathology and pathophysiology of inflammatory disorders of the gut. Enterochromaffin (EC) cells are the best-characterized GI endocrine cells, which are dispersed throughout the GI mucosa and are the main source of biogenic amine 5-HT in gut [5,15]. EC cells have specialized microvilli that project into the lumen, and contain enzymes and transporters

known to be present in the apical parts of the enterocytes [16]. EC cells function as sensors for the gut PAK5 contents and respond to luminal stimuli directly via these transporters and/or indirectly by mediators from the surrounding cells [16]. The GI tract contains about 95% of the body’s 5-HT, and EC cells are its main source [15,17]. 5-HT is also found in enteric neurones, but the 5-HT amount present in enteric neurones appears very small in comparison to that present in EC cells (approximately 90% of 5-HT in EC cells and 10% in enteric neurones) [17]. EC cells release 5-HT in a regulated and calcium-dependent manner in response to various mechanical and chemical stimuli, including bacterial toxins [3–5]. EC cells synthesize 5-HT from its precursor l-tryptophan. Tryptophan hydroxylase (TPH) catalyzes the rate-limiting step in the synthesis of 5-HT from tryptophan and has been detected prominently in EC cells [18].

reported that urinary TFF3 (uTFF3) levels were reduced, and urinary albumin levels increased in response to renal tubular injury in mice. In this study, we determined whether uTFF3 is an efficient biomarker in patients with early staegs of diabetic nephropathy. Methods: Spot urine samples were obtained from 79 male and 64 female type 2 diabetic patients (n = 143) in Okayama University Hospital. The levels of uTFF1, uTFF2, and uTFF3 were measured quantitatively by specific ELISAs to analyze the correlation between uTFF1, uTFF2, uTFF3 and various clinical parameters. Results: The level of uTFF3 significantly

increased in diabetic patients with microalbuminuria compared to those with normoalbuminuria (p = 0.0139). In contrast to the level of uTFF3, the level of uTFF1 or uTFF2 did not significantly elevate in diabetic patients with microalbuminuria RAD001 price Napabucasin cost compared to those with normoalbuminuria. Conclusion: These data indicate that the excretion of uTFF3 is selectively associated with microalbuminuria

in patients with diabetes mellitus. Further studies are necessary to elucidate whether the selective elevation of uTFF3 in association with microalbuminuria can predict the progression of diabetic nephropathy. WAN YIGANG1, SUN WEI2, HUANG YANRU3, MAO ZHIMIN3, CHEN HAOLI3, MENG XIANJIE3, TU YUE3 1Department of Traditional Chinese Medicine, Nanjing Drum Tower Hospital, The Affiliated Hospital of Nanjing University Medical School;

2Department of Nephrology, Jiangsu Provincial Hospital of Chinese Medicine, Affiliated Hospital Dynein of Nanjing University of Chinese Medicine; 3Department of Graduate School, Nanjing University of Chinese Medicine Introduction: Abelmoschus manihot (AM), a natural phytomedicine in China has been proved clinically effective in improving glomerularsclerosis (GS) in early diabetic nephropathy (DN) patients. However, therapeutic mechanisms involved in vivo are still unclear. Accumulating evidences demonstrate activation of mTOR plays a critical role in pathologic forms of hypertrophy and proliferation in kidneys under high-glucose condition other than classical TGF-beta1/Smad pathway. Hyperglycemia increases mTOR activity by combined actions of Akt activation and AMPK inhibition. This study thereby aimed to investigate effects and mechanisms of AM on GS through regulating Akt/mTOR/AMPK and/or TGF-beta1/Smad signaling activities in streptozotocin (STZ)-induced nephropathy rats. Methods: Rats were randomly divided into 3 groups, Sham-operated group, AM-treated group and Vehicle given group, and sacrificed at weeks 8 after induction of DN induced by 2 consecutive intraperitoneal injections of STZ at 30 mg/kg dose with an interval of 1 week following unilateral nephrectomy. Daily oral administration of AM and vehicle (saline) was started after the second injection of STZ until the day of sacrifice.

Yet another monocyte subpopulation of interest is the CD14+CD16+ circulating pool of cells

which is associated with acute or chronic inflammation [31, 32]. In our cohort, we found that patients with APS I had significantly less CD14+CD16+ cells than healthy blood donors (P = 0.028) (Table S2, Fig. 4). APS I is characterized by high titres of a broad spectrum of autoantibodies and increased immunoglobin levels. However, the frequencies of regular B cells and CD5+ B cells were unchanged in patients with APS I in comparison with healthy individuals (Table S2). The frequency learn more of NK cells (CD3−CD56+) was not significantly different between patients with APS I, relatives and controls. We further calculated the relative amount of subgroups of these cells. We first looked at NK cells expressing CD62L. This molecule mediates lymphocyte homing to high endothelial venules of peripheral lymphoid tissue and leucocyte rolling on activated endothelium at inflammatory sites [33]. Hence, obtaining information on the expression of this website CD62L on patient NK cells can indicate whether the migration of these cells is normal. However,

no differences in CD62L+ NK cells were found between the groups. CD16+ and CD16− NK cell subsets differ in their cytokine production capacity and so also in their role in immune regulation [34]. Patients with APS I expressed less CD16 in our study, although the results did not reach statistical significance (Table S2). Thirty-seven patients with APS I and 35 close relatives (the mutational status of AIRE was not known for all relatives)

were analysed for serum autoantibodies against several proteins known to be targeted in patients with APS I. All patients had antibodies against IFN-ω, and most of them also had antibodies many against one or more of the other included antigens. No relatives were found to exhibit autoantibodies against autoantigens found in APS I (Table 1). We have conducted a broad immunophenotyping study of relatively large cohorts of patients with APS I and relatives. Analysis of our patients with APS I revealed a few cellular abnormalities, some of which are novel. However, the distinctive changes in blood immune cell composition in patients with APS I were not observed in their family members. Norwegian patients with APS I exhibited reduced relative numbers of Tregs. These cells are known to be crucial for avoiding pathological autoimmunity. Mutations in FoxP3 cause the immune dysregulation, polyendocrinopathy, enteropathy, X-linked (IPEX) syndrome which is characterized by development of multiple autoimmune disorders in affected individuals. Aberrations in function of Tregs or their decreased numbers have been found in several autoimmune conditions, including early onset type 1 diabetes, APS II and in patients with the common variable immunodeficiency syndrome with autoimmunity [35–37].

11) in the NOD1-deficient animals when compared to WT controls. These data suggest that NOD1 deficiency impairs recruitment of inflammatory

cells to the lung during Lp infection. We next measured levels of cytokines and chemokines to examine the mechanism of NOD1-mediated protection. Cytokine levels from lung homogenates from WT, Nod1−/−, and Nod2−/− animals were measured for TNFα, IL-1β, IL-6, KC, IL-18, and MCP-1 to determine if there were significant differences in WT compared to Nod1−/− and Nod2−/− animals (Fig. 5). At 4 h, there was significantly decreased production of IL-1β (WT 1.00±0.06 versus NOD1 0.68±0.06 (mean±SEM)), KC (WT 1.00±0.12 versus NOD1 0.72±0.05), and trend toward decreased TNFα (WT 1.00±0.07 versus NOD1 0.78±0.09, p=0.06) in the Nod1−/− animals, when compared to WT controls (Fig. 5A, C, and G). In contrast, at 4 h, there was no change in IL-6, Palbociclib solubility dmso IL-18, or MCP-1 levels in the Nod1−/− animals (Fig. 5B, H, and I). At 24 h, Nod1−/− animals exhibited significantly increased levels of IL-6 production (WT 1.00±0.06 versus NOD1 1.35±0.13) compared to WT controls and a trend toward increased TNFα production (WT 1.00±0.08 versus NOD1 1.36±0.19, p=0.06). The only significant change seen in the Nod2−/− animals compared to WT controls at 4 h was a significantly increased production of IL-6 selleck kinase inhibitor (WT 1.00±0.36 versus NOD2 1.49±0.66) and

MCP-1 (WT 1.00±0.12 versus NOD2 2.04±0.49). In addition, significant increases were seen in Nod2−/− animals compared to WT in IL-1β (WT 1.00±0.19 versus NOD2 1.49±0.43), IL-6 production (WT 1.00±0.11 versus NOD2 Pyruvate dehydrogenase lipoamide kinase isozyme 1 1.49±0.20), and MCP-1 production (WT 1.00±0.10 versus NOD2 1.55±0.21) at 24 h (Fig. 5E, F, and L). In addition, IFN-γ was analyzed at the 24-h, 72-h and 10-day time points and only minimal production was seen in lung homogenates (our unpublished observations). The levels of IFN-γ were not different when comparing WT, Nod1−/−, and Nod2−/− mice. These data demonstrate

an early impaired production of proinflammatory cytokines KC and IL-1β seen in the absence of NOD1 protein and a later increase in proinflammatory markers (IL-1β, IL-6, and MCP-1) in Nod2−/− and (IL-6) Nod1−/− animals. Our data herein suggest that both NOD1 and NOD2 can detect Lp, but only NOD1 regulates in vivo bacterial clearance at 72 h. In addition, NOD1-deficient animals display early decreases in PMN recruitment to the alveolar space of the lung at 4 and 24 h and NOD2-deficient animals display a significant increase in PMN recruitment at 24 h. NOD1- and NOD2-deficient mice also show altered pulmonary inflammatory cell infiltration and cytokine responses to Legionella. In our aerosolized animal model, we identified higher Lp CFU in Nod1−/− mice compared to WT controls. Delayed bacterial clearance of Lp has been a characteristic of other knockout systems.

Remarkably, the finding that PstS1 stimulates memory T cells specific for TT, suggests the potential exploitation of PstS1 immunomodulatory properties in other infections. Although effects on other APCs cannot be excluded, our study shows that the immunomodulatory properties of PstS1 are linked to its ability to activate DCs in vitro and in vivo. In particular, PstS1 promoted

the expression of IL-6, IL-1β, and, to a minor extent, IL-23. These cytokines were recently reported to drive a fine balance of CD4+ T-cell differentiation in the effector phase of the immune response to Candida albicans and Staphylococcus aureus [44]. Of interest, other cytokines pivotal for the homeostasis of memory T cells, such as IL-7

and IL-15 for CD8+ T cells [45], or IL-12p40 for Th1 Small molecule library solubility dmso response [46], were INCB024360 cell line not modulated by PstS1 (data not shown). The ability to stimulate DCs was peculiar to PstS1, since other immunodominant Mtb Ags such as Ag85B, Esat-6, or HBHA were unable to activate DCs (Fig. 4 and data not shown) and it was directed preferentially toward CD8α− DCs. The two major DC subsets of mouse spleen, CD8α+ and CD8α−, trigger distinct T-cell responses against pathogens. While CD8α+ DCs are thought to be specialized in antiviral response due to their unique cross-priming ability, CD8α− DCs have been involved in CD4+ T-cell immunity, particularly during bacterial infections [47]. CD8α− DCs efficiently induce CD4+ next T-cell responses through in vivo targeting of Ag via C-type lectin receptors, such as dectin-1 and DCIR-2 [30, 48]. The preferential ability of CD8α− DCs to prime CD4+ T-cell responses has been correlated with their superior capacity to process Ags via MHC class II molecules [30]. Accordingly, we report that PstS1 endowed CD8α− DCs with a strong ability to simulate CD4+ T cells. In particular, CD8α− DCs stimulated by PstS1 were found to produce much higher amounts of IL-6, IL-1β, and IL-23 with respect

to CD8α+ DCs. Moreover, PstS1-pulsed CD8α− DCs were far superior at inducing IFN-γ, IL-17, and IL-22 release by Ag85B-specific memory T cells, compared with CD8α+ DCs. The mechanisms by which PstS1 activates DCs remain to be established. Our data on DCs deficient for TLR2, the main PRR recognized by Mtb components, suggest that this receptor is dispensable. We envisage that the TLR2-independent pathway of DC maturation induced by PstS1 strongly differs from that triggered by the Mtb Ags Rv0577, Rv1196, Rv0978c, and Rv0754, which all recognize TLR2 and induce maturation of DCs leading to either Th1 or Th2 polarization, but not to IL-17 secretion by memory CD4+ T cells [14-18].

TNF-α decreases the Ca2+ permeation and increases the basal level of [Ca2+]cyto after a Ca2+ pulse (P < 0.04); affecting calcium regulation in a way that is time and concentration dependent. TNF-α effect was partially prevented by the addition of an antioxidant (butylated hydroxytoluene) (P < 0.03). Tumor necrosis factor-α decreases membrane permeability to Ca2+ and affects Ca2+ regulation in sperm cells in vitro, probably via lipid peroxidation, which may explain the decrease in sperm fertilizing capacity during inflammatory and infectious processes. "
“Centre

d’Immunologie Marseille-Luminy (CIML), Parc Scientifique de Luminy, 13288 Marseille, France Monash Immunology and Stem Cell Laboratories (MISCL), Monash University, Clayton, selleck inhibitor Victoria 3800, Australia The human butyrophilin (BTN) 3 or CD277 molecules

belong to the B7 family members and are expressed in various immune cells such as T and NK cells. Here, we show that Napabucasin CD277 triggering considerably enhances TCR-induced cytokine production and cell proliferation, even when another co-stimulatory molecule, CD28, is engaged. These CD277-induced additive functional effects are in accordance with the detection of early T-cell activation events such as TCR-induced cell signaling being increased upon CD277 engagement. However, we found that CD277 triggering is not involved in CD16- or NKp46-induced NK cell activation. BTN3/CD277 comprises three structurally related members, BTN3A1, BTN3A2 and BTN3A3. CD277 antibodies recognize all isoforms and we describe a differential expression of BTN3 isoforms between T and NK cells that could explain differential CD277 functions between T and NK cells. Our results show that, while T cells express all BTN3/CD277 transcripts, NK cells express mostly BTN3A2, which lacks the B30.2 intracellular domain. Furthermore, NKp30-induced cytokine production is decreased by the specific engagement of BTN3A2, but not by BTN3A1 triggering. Thus, we provide new insights into the CD277 co-stimulatory pathway that may differentially participate in the regulation Dynein of various cell-mediated immune responses. The human

butyrophilin (BTN) 3 (also known as CD277) molecules belong to the B7 family members and are expressed in various immune cells such as T cells and NK cells 1. The molecules comprise three structurally related members, BTN3A1, BTN3A2 and BTN3A3 2, 3. Structurally, the BTNs are composed of an extracellular IgV-like domain, followed by an IgC-like domain and a heptad repeated sequence 2–7. Some BTNs harbor an intracellular domain of 166 amino acids, named B30.2, presumably involved in intracellular signal transduction, notably the BTN implied in the regulation of superoxide concentrations 8, 9. BTN3A1, BTN3A2 and BTN3A3 exhibit 95% identity and form a mono-phylogenetic group along with the B7/BTN-related members 1. However, only BTN3A1 and BTN3A3 display the B30.

Primers and probes were used as previously described [31–33]. The methods,

primers and probes used for the quantification of coronavirus [34], poliovirus [35] and influenza A [36] were used as previously described. Morbillivirus was quantified using forward primer 5′- CGT TGA CCC TGA CGT TAG CA -3′, reverse primer 5′- GCG AAG GTA AGG CCA GAT TG- 3′ and the probe sequence was 5′- GTC CTC AGT AGT ATG CAT TGC AA- 3. All viruses were inactivated AZD1152-HQPA purchase at 2500 rad and stored at −70 °C before use. Bacterial strains.  The bacterial strains were isolated from stool samples of Swedish infants obtained at 3 days–8 weeks of age. Staphylococci were isolated on staphylococcus agar and identified as Staphlococcus

aureus using the coagulase test. A S. aureus isolate that produced enterotoxin A and toxic shock syndrome toxin-1 (TSST-1), but not enterotoxins B, C or D, was learn more tested for enterotoxin production using the SET-RPLA kit, and for TSST-1 using the TST-RPLA kit (both kits from Oxoid, Hampshire, UK). Escherichia coli was isolated on Drigalski agar (Media Department, Gothenburg University, Sweden) and was identified using the API20E biotyping system (bioMérieux Industry, Marcy l’Etoile, France). B. bifidus was isolated on Beerens agar (Media Department) selleck and identified by genus-specific PCR. Lactobacillus rhamnosus was isolated on Rogosa agar (BD Diagnostics), and Clostridium difficile was isolated from alcohol-treated samples and identified using the RAPID ID 32A system (bioMérieux Industry). Prior to use in cell culture, all strains were counted in a microscope and inactivated by exposure to UV-light for 20–30 min. Inactivation was confirmed by negative viable counts and the bacteria

were stored at −70 °C until use. Purification of cells.  Cord blood was obtained from unselected healthy infants. Buffy coats were obtained from the blood central at Sahlgrenska University Hospital. Cells were isolated by density gradient centrifugation over Ficoll–Paque (GE Healthcare Bio-sciences AB, Uppsala, Sweden). Fresh pDC and mDC were isolated from cord and adult blood using the pDC isolation kit CD304 (BDCA-4) (purity: 79–92%) and the mDC isolation kit CD1c (BDCA-1) (purity: 85–96%), both from Miltenyi Biotec (Auburn, CA, USA). The mean yield for pDC and mDC were 0.34% (range: 0.14–0.6%) and 1.1% (range: 0.42–1.45%), respectively. CD4+ T cells were isolated from cord and adult blood using the Dynal CD4+ isolation kit (Invitrogen Dynal AS, Oslo, Norway) (purity: >95%). All separations were carried out according to the manufacturer′s instructions. Mixed lymphocyte reaction.

It is interesting that the 7/16-5 TCR is expressed on CD8+ T cells as well as CD4+ T cells although both CD4+ and CD8+ T cells are specific for p120–140 in the context of MHC class II molecules (I-Ab). It is possible that the 7/16-5 TCR may also recognize

a self-peptide in the context of MHC class I molecules in the thymus with sufficient affinity to be selected on MHC class I. To address this question, we bred 7/16-5 × HBeAg dbl-Tg mice on a MHC class I negative background. While HBeAg × 7/16-5 dbl-Tg mice on a MHC class I KO background do not produce mature CD8+ T cells in the periphery, selleck products HBeAg-specific DN T cells are produced, and are, therefore, not dependent on MHC class I or CD8 expression. Endogenous TCR-α chains also do not affect the presence of DN T cells in the periphery. At present, we have no direct evidence to address whether this see more DN Treg cell population is unique to this model or not. The frequency of this population is low in situ in 7/16-5 × HBeAg dbl-Tg mice and their presence in other systems may be difficult to detect. The 7/16-5 × HBeAg dbl-Tg mice may be a useful model for low-affinity self-reactive T cells that escape deletion in the thymus and are quiescent in the periphery until activated (i.e. tissue injury, mimicked here by high concentrations of peptide in

vitro or in vivo). Most dbl-Tg mice are models of high-affinity self-reactive T cells, which are largely deleted in vivo. It is anticipated that further characterization of this low-affinity DN Treg cell population may yield a phenotypic marker that would allow identification in other systems. Recent publications have suggested that Treg cells may contribute to impaired immune function in an HBV-Tg mouse model 44 and in patients

with chronic HBV.45–47 Furthermore, in one study, in which the T-cell PRKACG response to HBcAg was studied, an increase in Treg cell frequency and function was observed in HBeAg-positive patients compared with HBeAg-negative patients, suggesting a role for HBeAg.46 Previous studies of Treg cells in either an HBV-Tg mouse model or HBV-infected patients have concentrated exclusively on CD25+ Treg cells or cTreg cells. The HBeAg-specific DN Treg cells observed in the 7/16-5 × HBeAg dbl-Tg mouse model may serve as a useful tool to study functional characteristics of HBeAg-specific Treg cells in general such as clonal expansion and mechanisms of suppression, which may have implications for viral persistence during natural HBV infection. We thank David Chambers and Jonna Barrie for operating the Salk Institute Flow Cytometry facility, Darrell Peterson (Virginia Commonwealth University) for providing recombinant HBcAg and Frank Chisari (The Scripps Research Institute) for providing HBc/HBeAg-Tg mice. This work was supported by the National Institutes of Health grants AI 20720-28, and AI 049730-08. The authors have no conflicts of interests to declare.