Moreover, selleck kinase inhibitor differences in the nature of cell stimuli has

been proposed as the reason for NETs consisting of either nuclear DNA [3], mitochondrial DNA [6] or a combination of both [16]. While the majority of reports of NET release involve the eventual rupture of the neutrophil plasma membrane [3,4,15], early S. aureus-stimulated NET release (5–60 min) has been reported to occur via a process akin to exocytosis without plasma membrane rupture [16]. Furthermore, NETs comprising only mitochondrial DNA are reported to originate from cells remaining viable [6]. Here we demonstrate, for the first time, the requirement of hypochlorous acid (HOCl) for NET release and a potential regulatory role for endogenous taurine in this process. In our studies, for NET stimulation, PMA was employed to stimulate PKC in place of the endogenous activator, diacylglycerol. PMA, which is known to stimulate NADPH oxidase generation of ROS in neutrophils, has also been reported to elicit dramatic NET release [3]. Although less physiologically relevant, PMA provides direct intracellular stimulation, removing the complication of multiple simultaneous signalling pathways and responses that are likely to be evoked in neutrophils

stimulated with more physiologically relevant receptor-mediated stimuli such as un-opsonized (Toll-like receptor; TLR) or opsonized (Fcγ-receptor) bacteria. In addition, this form of stimulation is consistent with many previously reported studies. RPMI-1640 was obtained from Biosera (Ringmer, UK), Percoll from LDE225 concentration GE Healthcare (Little Chalfont, UK), SYTOX green nucleic acid stain was obtained from Invitrogen (Paisley, UK), 96-well plates were from Corning (Lowell, MA, USA), InnoZyme Myeloperoxidase Activity Kit was from Calbiochem (Nottingham, UK), micrococcal nuclease was from Worthington Biochemical Corporation (Lakewood, NJ, USA) and tryptone soy agar and broth were from Oxoid (ThermoFisher Scientific, Basingstoke, UK). All other chemicals were purchased from Sigma (Gillingham, UK). Unless specified otherwise, all ex-vivo experiments were conducted using human neutrophils from medically healthy volunteers and were isolated from venous blood by discontinuous

Bay 11-7085 Percoll density gradient followed by ammonium chloride lysis of red blood cells, as described previously [19]. Patients with chronic granulomatous disease (CGD) were recruited from the Department of Immunology, Birmingham Heartlands Hospital, following informed consent (West Midlands Research Ethics Committee number 10/H/1208/48). Neutrophils (1 × 105) in RPMI-1640 were seeded into bovine serum albumin (BSA)-coated [1% in phosphate-buffered saline (PBS)] 96-well plates and allowed to settle for 30 min at 37°C in the presence of the inhibitors or enzymes being tested. Cells were stimulated with 25 nM PMA or 0·75 mM HOCl and incubated for 3 h at 37°C [2]. NET-DNA was quantified using a modified version of a previously published method [20–22].

In this study, 2 of 10 patients showed immunoreactivity against the flagellar hook protein, which may indicate that the C. concisus

flagellum is subject to phase variation and antigenic variation as is seen in C. jejuni and H. pylori (van der Woude & Baumler, 2004), making potential species-specific antigen detection using clinical serum samples even more difficult. Comparison of C. concisus ATP synthase F1 alpha Paclitaxel in vivo subunit with other Campylobacter species revealed high sequence identity (89–97% for C. curvus, C. rectus, C. lari, and C. jejuni), which corresponded with our experimental results. Using absorbed sera, OMP18 could not be detected by immunolabeling, indicating high cross-reactivity among

C. concisus, C. showae, C. jejuni, and C. ureolyticus (data not shown). However, this is not surprising in view of the overall conservation among Gram-negative bacteria of the functionally important peptidoglycan-associated lipoproteins (Burnens et al., 1995; Konkel et al., 1996). Indeed, immunoblot analysis with mono-specific anti-OMP18 antibodies has shown that similar proteins are expressed in many Campylobacter species (Burnens et al., 1995). Despite observing strong cross-reaction for OMP18, sequence comparison of C. concisus OMP18 with C. jejuni and H. pylori revealed 54% and 38% identity, respectively. Overall, the results indicated that many of the identified C. concisus antigens do not cross-react with PLX4032 molecular weight C. ureolyticus antigens; however, they do cross-react with C. jejuni antigens, with the cross-reaction with C. showae antigens being even Rutecarpine stronger. This finding is in line with the closer genetic relationship between C. concisus and C. showae as seen by

phylogenetic analyses (Man et al., 2010a). Other proteins of interest included ATP synthase alpha subunit, the hypothetical protein CCC13826_1437, and translation elongation factor Tu that reacted with sera from five, five and six patients, respectively. However, these proteins are highly conserved among other Campylobacter species, which correlated with their lack of reactivity when probed with absorbed sera. Interestingly, although their amino acid sequences were also highly conserved among Campylobacter species, the immunoreactivity of the outer membrane protein assembly complex YaeT protein (one patient), fumarate reductase flavoprotein subunit (two patients), hydrogenase-4 component I (one patient), and transketolase A (four patients) remained unaffected after serum absorption with the different bacteria. As these antigens reacted only with a small number of C. concisus-positive patients’ sera, the importance of these antigens requires further investigation. An outer membrane fibronectin-binding protein (56% similarity to C. jejuni NCTC 11168 CadF) was also identified to be immunoreactive in four of the C. concisus-positive CD patients.

Hence, IL-33 signalling via ST2, by inducing an IL-4-dependent immune response, may be a major pathogenic

factor in the exacerbation of ulcerative colitis. Ulcerative colitis (UC) is an inflammatory disease of the colon associated with recurring inflammation and the formation of ulcers.[1] This leads to clinical symptoms and signs including diarrhoea and serious complications, such as peritonitis and increased risk of colorectal cancer.[1] The aetiology of UC is largely unknown, which is the main reason why current GPCR & G Protein inhibitor therapeutic options are limited. Environmental and infectious disease factor-mediated barrier dysfunction and abnormal angiogenesis in gut epithelium are thought to play a critical role in the initiation and perpetuation of the disease.[1, 2] Dextran sulphate sodium (DSS) -induced colitis in mice is a well-established model for human UC.[3] Mice fed with DSS polymers develop disease similar to human UC, characterized by diarrhoea, colonic inflammation and ulceration. This is a result of direct toxic effects of DSS on the gut epithelial cells of the basal crypts.[3, 4] The induction of acute DSS-induced Buparlisib molecular weight colitis does not depend on lymphocytes;[4] therefore it is a particularly useful model

to study innate immune mechanisms of the intestinal epithelium in the pathogenesis of colitis. The pathogenesis of ulcerative colitis in humans and animal models is primarily associated with dysregulation of type II cytokines [interleukin-4 (IL-4), IL-5 and IL-13],[2, 5-7] whereas type I [interferon-γ (IFN-γ)], and pro-inflammatory [IL-1, IL-6, IL-17 and tumour necrosis factor-α (TNF-α)] check details cytokines may also contribute to the pathogenesis, probably in the chronic phase of UC.[2, 8-10] The early innate inflammatory

signal(s) that coordinate the engagement of these cytokines are unresolved although IL-33, a new member of the IL-1 family, is a potential candidate.[11] Interleukin-33 is a pleiotropic cytokine that signals via its receptor ST2 and can elicit different immune responses depending on context.[11, 12] It is expressed primarily in the epithelium and endothelium and can be released when cells sense inflammatory signals or undergo necrosis.[11, 12] The IL-33 receptor, ST2, is expressed by almost all innate cells but only by selected adaptive immune cells.[11-17] Interleukin-33 signalling via ST2 can induce both antigen-dependent and antigen-independent type II immune responses by directly activating a wide-range of innate immune cells including eosinophils, macrophages, nuocytes, mast cells or T helper type 2 (Th2) and IL-5+ Th cells in vitro and in vivo.[11-17] In addition, IL-33 can also promote Th1 and/or Th17 type responses in pro-inflammatory disorders in mice, by as yet undefined mechanisms.[18, 19] Increasing evidence suggests that IL-33 and ST2 play a pathogenic role in inflammatory bowel disease.

They have been assayed with moderate success in different therapeutic settings to treat colorectal carcinoma [29], melanoma [20], gastric [30], bladder [31], ovarian, and breast cancer [32-34]. Viral dsRNA is normally recognized by TLR3 and RLRs in a cell-type and pathogen-type specific manner. TLR3 has been shown to be expressed on human Anti-infection Compound Library lung carcinoma cells [35] and in lung epithelial cells [36]. Besides, functional expression of TLR3 has been detected in

human prostate cancer cell lines and in murine models of prostate cancer [37-39]. Also, it has been published that TLR3 is intracellularly localized in melanoma cells, where it can deliver proapoptotic and antiproliferative signaling. Poly IC activates the TLR3 pathway leading to suppression of the viability of melanoma cells [20, 40]. The murine melanoma B16 cells have also

been reported to respond to poly AU [29]. We chose the human lung carcinoma cell line A549, the human prostate carcinoma cell line DU145, and the murine melanoma cell line B16 because they were all reported to express TLR3 and to respond to dsRNA therapy. However, the fact that the levels of IFN-β induction upon poly I:C or poly A:U stimulation were capable of improving DC function had not been reported MLN8237 purchase before. dsRNA from engulfed apoptotic infected cells is recognized by TLR3 in endosomes, triggering a MyD88-independent response whereas activation of RLRs by viral dsRNA occurs in cytosol and engages a different set of molecular adaptors [1-3]. However, triggering any of these receptors before ends in activation of the transcription factors IRF3 and NF-κB and the production of type I IFNs and pro-inflammatory cytokines. A549 cells and DU145 cells (data not shown) upregulate the expression levels of both TLR3 and RLRs. DU145 and A549 human cancer cells respond to dsRNA analogs, inducing an important IFN response and pro-inflammatory cytokines. Phosphorylation of IRF3 was readily observed as well as phosphorylation of STAT1 24 h after the initial stimulus. The latter indicates that type I IFNs are acting in an autocrine fashion on tumor

cells, as previously described [8, 9]. Interestingly, the expression of type I IFN receptor has been shown in different epithelial tumors but not in sarcomas, lymphomas, and endocrine tumors [41]. We cannot exclude the possibility of a heterogeneous expression of IFNAR among the tumor cell population, which could promote an in vivo selection of tumor cells refractory to type I IFN stimulation. Our results show that IFN-β produced by dsRNA-activated tumor cells can also act in a paracrine fashion, as determined by the presence of pSTAT1 after incubation of MoDCs and BMDCs with dsRNA-CM (Fig. 2 and Supporting Information Fig. 1). PIC-CM by itself was capable of inducing the upregulation of CXCL10 mRNA, CD40, and CD86 expression levels on MoDCs, but not the secretion of IL-12p70.

“
“Hookworms are one of the most

prevalent parasites of humans in developing countries, but we know relatively little about the immune response generated to hookworm infection. This can be attributed to a lack of permissive animal models and a relatively small research community compared with those of the more high-profile parasitic diseases. However, recently, research has emerged on the development of vaccines to control hookworm infection and the use of hookworm to treat autoimmune and allergic disorders, contributing to a greater understanding of the strategies used by hookworms to modulate the host’s immune response. A substantial body of research on the immunobiology of hookworms originates from Australia, so this review will summarize the current status of the field with a particular emphasis on research carried out ‘down under’. learn more Hookworms are one of the most common

parasites of humans, with around 740 million people infected worldwide. Although they cause little mortality, heavy infections can cause iron-deficiency anaemia, growth retardation and low birth weight (1). Hookworms are most prevalent in South America, sub-Saharan Africa and East Asia; however, up until the second half of the 20th century, they were also common in the southern states of USA, Europe (2) and Australia, where they still affect some remote aboriginal communities (3). The two major anthropophilic hookworm species are Necator americanus Dorsomorphin chemical structure and Ancylostoma duodenale. The more common parasite, on which the majority of studies have consequently been carried out, is N. americanus. Hookworms are soil-transmitted helminths: infective larvae burrow through the skin and are activated in the process, after which they migrate through the heart and lungs to the gut, where they mature to adults, feed on host blood and produce eggs which are deposited in the faeces. Deposited eggs then develop to infective larvae, completing the life cycle (1). The host Vasopressin Receptor must therefore mount an immune response against a number of different parasite

stages during a hookworm infection, and the parasite in turn has a number of opportunities to manipulate the host immune system. We will not dwell on the life cycle of the parasite in this review – for more detail, see (4). The immunology of human hookworm infection has not received as much focus as that of other helminth parasites of humans, such as schistosomes and filariae. The reasons for this include the relatively low mortality caused by hookworms, the difficulty/expense in maintaining the life cycle in a suitable animal model and the inability of any of the major species of hookworms to reach maturity in mice. This has especially been a problem in Australia where the best laboratory model, the hamster, is not permitted to be maintained in the country because of quarantine regulations. Consequently, Australian hookworm research has focussed on human immunology, and especially experimental or zoonotic human infections.

We evaluated the clinicopathological

factors between the progression and the non-progression groups. Systolic, diastolic, and mean blood pressures were significantly higher in the progression group. Degree of hematuria was not associated with CKD progression. Segmental glomerulosclerosis and tubular atrophy/interstitial fibrosis characterized advanced risk for CKD progression. CKD selleck chemicals stage did not progress in cases of mild pathological activity without ACEI/ARB. The baseline renal function, proteinuria, hypertension, the degree of mesangial and endocapillary hypercellularity, and values of IgA at biopsy were not associated with CKD progression during the three year follow-up. Proteinuria and hematuria decreased, and serum albumin increased significantly due to treatment regardless of CKD progression. Conclusion: We can protect renal function by adequate treatment at least for a three year follow-up period after

biopsy, despite high disease activity of IgAN indicated by proteinuria, hematuria, decrease of estimated GFR, and active pathological findings. Further follow-up must be needed to detect predictors associated with long-term renal prognosis. Suzuki Keisuke, Miura Naoto, Imai Hirokazu Aichi Medical University School of Medicine Background: This retrospective study was designed to estimate the clinical remission (CR) rate of tonsillectomy plus steroid pulse (TSP) therapy in patients with IgA nephropathy. Methods: Based on 292 of 302 patients with IgA nephropathy treated at 11 Japanese hospitals, we constructed Selleckchem AZD4547 heat maps of the CR rate at 1 year after TSP with the estimated glomerular filtration rate (eGFR), grade of hematuria, pathological grade, number TCL of years from diagnosis until TSP, and age at diagnosis on the vertical axis and the daily amount of urinary protein on the horizontal axis. Results: The first heat map of eGFR and urinary protein showed that the CR rate was 71 % in patients with eGFR greater than 30 ml/min/1.73 m2 and 0.3–1.09 g/day of urinary protein. However, the CR rate in patients with more than 1.50 g/day of urinary protein was approximately 30 %. The

second heat map of grade of hematuria and urinary protein revealed that the CR rate is 72 % in patients with more than 1? hematuria and 0.3–1.09 g/day of urinary protein; however, it was 28.6 % in patients with no hematuria. The third heat map of pathological grade and urinary protein demonstrated that the highest CR rate was 83 % in patients with pathological grade I or II disease and less than 1.09 g/day of urinary protein, as opposed to 22 % in patients with pathological grade III or IV disease and more than 2.0 g/day of urinary protein. The fourth heat map of the number of years from diagnosis until TSP and urinary protein revealed that the former did not influence the CR rate in patients with less than 1.09 g/day of urinary protein. However, in patients with more than 1.

Rabbit monoclonal Ab against GAPDH was obtained from Cell Signaling Technology NVP-BGJ398 in vivo (Danvers, MA). Western blotting of lung homogenates was performed as described previously [[46, 47]]. RNA was extracted from lung homogenates and cells with Trizol (Invitrogen Life Technologies, Carlsbad, CA) according to the manufacturer’s instructions. Reverse transcription was performed using 1.5 μg of RNA and cDNA was amplified using gene-specific primers [[48, 49]]. The results were normalized with GAPDH. MPO assay was performed as described previously (15). Samples were homogenized in 50 mM hexadecyltrimethylammonium bromide

(HTAB) and assayed as previously described [[45, 50]]. H2DCF dye (Molecular Probes) does not normally Selleckchem Ku0059436 fluoresce under resting conditions, but emits green fluorescence upon reaction with superoxide inside cells. Cells were treated as above and equal amounts of dye added [[16]]. This assay measures color change of MTT upon reduction by enzymes to assess the viability of cells. After infection of MLE-12 cells with K. pneumoniae, MTT dye was added at a final concentration of 1 μg/mL as described previously [[47]]. We used LipofectAmine2000 to transfect cells at 60% confluency and achieved high efficiency in transfection [[22, 51]]. The yellow fluorescent protein (YFP)-Cav-1, YFP-Cav-1Δ51-169 dominant negative (DN) plasmids were generated as described previously [[18]].

MLE-12 cells were infected with K. pneumoniae at MOI 10:1 for 1 h and the free bacteria were removed by washing three times with PBS. The surface bacteria were killed by incubation with 100 μg/mL polymyxin B for 1 h and intracellular bacteria were enumerated to determine CFU. Transfection with cav1 DN plasmid did not affect survival of MLE-12 cells prior to incubation with K. pneumoniae. WP1066 (a novel STAT5 inhibitor from Sigma) was dissolved in 1% DMSO solution and used at a final concentration of 2 μM in culture medium. No adverse effect of the vehicle control was observed in the assays. The differences

in outcomes between cav1 KO and WT control animals after K. pneumoniae infection were calculated by Kaplan–Meier survival curve comparisons, and the Idoxuridine p values were derived from a log-rank test. Most experiments were performed three times in triplicate. Comparison of experimental groups with controls was done with one-way ANOVA (Tukey’s post-hoc) [[16, 52]]. This project was supported by NIH ES014690, Flight Attendant Medical Research Institute (FAMRI, 103007), and American Heart Association Scientist Development Grant (MW); and by NIH 5R01HL092905-04 and 3R01HL092905-02S1 (HG). We thank S. Rolling of UND imaging core for help with confocal imaging. The authors declare that they have no competing financial interests. Disclaimer: Supplementary materials have been peer-reviewed but not copyedited.

IL-4−/− mice (von der Weid et al., 1994) that had been backcrossed with C57BL/6 mice at least 10 times were purchased from The Jackson Laboratory (Bar Harbor, ME). IFN-γ+/− and IL-4+/− mice were generated by mating the IFN-γ−/− mice and IL-4−/− mice with C57BL/6J WT mice. All mice were housed and bred in the Animal Unit of the Kobe University School of Medicine in a specific pathogen-free facility under an approved experimental

protocol. Six-week-old C57BL/6J WT (n=20 : 10 for the mice at 6 weeks after infection and 10 for the mice at 12 weeks after infection), IFN-γ+/− (n=5), IFN-γ−/− (n=5), IL-4+/− (n=5), and IL-4−/− (n=5) mice were infected with H. suis, which was originally obtained from a Cynomolgus monkey Palbociclib datasheet and was genetically identified as ‘H. heilmannii’ type 1 using its 16S rRNA and urease gene sequences in previous reports (O’Rourke et al., 2004b; Nakamura et al., 2007). Helicobacter suis was maintained in the stomachs of C57BL/6J AZD6244 order WT mice, because this bacterium

has not been successfully cultivated in our laboratory. C57BL/6J mice were used as donors of bacterium at 3–6 months after H. suis infection. Gastric mucosa was carefully scraped from a stomach using cover glass and homogenized in 1 mL of phosphate-buffered saline. Then, 0.2 mL of gastric mucosal homogenate containing the gastric mucus and mucosa of the infected mice was orally administrated to each mouse. Six-week-old C57BL/6J WT (n=20 : 10 for the mice at 6 weeks after infection and 10 for the mice at 12 weeks after infection) were used as the control animals. Helicobacter suis infection was confirmed with PCR using DNA samples extracted from gastric mucosal homogenates and primers for HHLO 16S rRNA

gene; i.e. 5′-AAGTCGAACGATGAAGCCTA-3′ and 5′-ATTTGGTATTAATCACCATTTC-3′ (Chisholm & Owen, 2003). A control experiment was performed using DNA samples extracted from gastric mucosal homogenates or H. pylori ATCC43504 and primers for H. pylori 16S rRNA gene; i.e. 5′-TGCGAAGTGGAGCCAATCTT-3′ and 5′-GGAACGTATTCACCGCAACA-3′. Six or 12 weeks after H. suis inoculation, infected WT mice were sacrificed by cervical dislocation under anesthesia. Thiamet G Tribromo ethanol was used as an anesthetic agent, and 1.5 mg per mouse of tribromo ethanol was intraperitoneally injected. The stomachs were resected and opened at the outer curvature. The stomachs were then sliced longitudinally from the esophagus to the duodenum. Half of the stomach was embedded in paraffin wax; one quarter of the stomach was used for DNA and RNA extraction, as described below, and the remaining specimen was frozen in OCT. Compound (Sakura Finetek, Tokyo, Japan). Twelve weeks after H. suis infection, the stomachs of IFN-γ+/−, IFN-γ−/−, IL-4+/−, and IL-4−/− mice were resected and prepared as described above. The paraffin-embedded tissues were longitudinally sliced into three specimens and stained with hematoxylin and eosin (H&E).

Comparison between groups this website in bDNA assays was carried out using Student’s t-test after checking the normal distribution of values with Normal QQ plots test and the variance within groups with the F-test. It is of note that for SV2C values, the MTS1A group showed a much higher variance than the other groups, did not approximate a Gaussian distribution and rather assumed a bimodal pattern (see Figure 1). The analysis of covariation between dynorphin, ZnT3 and SV2C IR scores and SV2C mRNA levels was performed using the Spearman rank correlation test. Correlation was considered significant for two-tailed P-value < 0.05. Statistical analysis was carried out using the

R-cran statistical software (R Core Team [34]) (Table 3). Quantitative mRNA data on the expression of SV2A, SV2B and SV2C are shown in Figure 1 and individual

values are given in supplementary Table S1. Experiments have been carried out in triplicate and graphs show the mean value of the three experiments. SV2A and SV2B expression was globally decreased in cases of MTS and gliosis, reflecting the overall synaptic loss. All comparisons between TLE groups and controls reach statistical significance with P-values ≤ 0.05 check details (see Figure 1). SV2C mRNA was globally increased in the group of MTS1A, and this increase was statistically significant using Student’s t-test. The MTS1A group appeared heterogeneous however, with five cases showing high levels of SV2C (NC1, NC6, NC26, NC28 and NC33) while the other 13 showed mild or no SV2C increase. There was an excellent agreement between mRNA quantification and IR data indicating that overexpression of SV2C occurs at both mRNA and protein level (see text below and Table 3). The five cases that were positive by both methods have been labelled with colours in Figure 1. We used immunohistochemistry to identify the distribution pattern of

SV2 isoforms in controls and TLE cases. In autopsy controls, SV2A and SV2B IR was seen in all subfields of the hippocampus and closely matched the pattern of synaptophysin, as expected for a selective presynaptic staining (Figure 2b–d) [19, 35]. It is of note that SV2B IR was consistently weaker than SV2A BCKDHB and synaptophysin, particularly in the CA4 and CA3 areas. Most often no staining for SV2C was seen throughout the hippocampus (Figures 2e and 3a). Only in rare cases, there was a faint staining confined to synapse aggregates in CA4. These results suggest that, while SV2A and SV2B are widely distributed, SV2c expression, when present, is restricted to the axonal projections of neurones from the granular cell layer of the dentate gyrus (GCL), the so-called mossy fibre pathway targeting CA3 and CA4 pyramidal neurones [36, 37]. We compared SV2C with dynorphin IR, as this opioid peptide is expressed in mossy fibres [22]. As expected, in controls dynorphin IR was seen in GCL, in the innermost portion of the molecular layer, in the hilus (CA4) and in the stratum lucidum (CA3) (Figure 3b).

[1] Donor-derived T cells are considered the main effector cells mediating acute GVHD because they recognize MHC disparities (allo-antigen) between the donor and recipient, which are presented by antigen-presenting cells (APC). T-cell activation in response to allo-antigen Selleckchem CHIR-99021 requires two stimulatory signals.[1] The primary signal is delivered through the T-cell receptor (TCR), which recognizes antigens on MHC molecules. This signal is necessary but not sufficient to induce full T-cell activation, which also requires co-stimulation that drives T cells to proliferate and produce cytokines. The co-stimulation signal is mediated by a number of ligand–receptor pairs expressed

on APC and T cells, and is a composite or net effect of stimulatory and inhibitory signals mediated between these two

cells. The inhibitory TCR include cytotoxic T-lymphocyte antigen-4 (CTLA-4),[2] programmed cell death-1 (PD-1)[3] and B- and T-lymphocyte attenuator selleck chemicals (BTLA).[4] Studies using experimental models of acute GVHD have shown that co-stimulatory molecules play a pivotal role in initiating acute GVHD.[5] By contrast, much less is known about co-inhibitory pathways in this process, better understanding of which would make them useful therapeutic targets. Recently, we discovered a new co-inhibitory pathway composed of DC-HIL on APC and syndecan-4 (SD-4) on activated T cells.[6, 7] DC-HIL is a highly-glycosylated type I transmembrane receptor (95 000–120 000 molecular weight) expressed constitutively by many APC sub-sets including

macrophages, monocytes, epidermal Langerhans cells, CD11c+ CD4+ lymphoid dendritic cells (DC), CD11c+ CD8+ myeloid DC and CD11c+ PDCA-1+ plasmacytoid DC.[8] It is also known as glycoprotein nmb (Gpnmb),[9] osteoactivin[10] and haematopoietic growth factor-inducible neurokinin-1 type (HGFIN).[11] DC-HIL binds to heparan sulphate-like structures on SD-4 expressed by activated (but not resting) T cells, 5-Fluoracil and their binding inhibits strongly the anti-CD3 response of T cells, resulting in cessation of interleukin-2 (IL-2) production and prevention of T-cell entry into the cell cycle.[6, 12] Consistent with a previous finding that SD-4 is expressed primarily by effector/memory (but not recently activated) T cells,[13] infusion of DC-HIL or SD-4 soluble receptor during the elicitation (but not sensitization) phase of contact hypersensitivity effectively blocked the inhibitory function of the endogenous DC-HIL/SD-4 pathway, thereby enhancing ear-swelling responses in this experimental model.[7] Conversely, depletion of SD-4+ T cells by infusion of toxin-conjugated DC-HIL inhibited elicitation (but not sensitization) of contact hypersensitivity.[13] These findings support the concept that binding of DC-HIL to SD-4 inhibits pre-primed T-cell responses. To determine whether SD-4 is the sole T-cell ligand of DC-HIL and whether its negative regulatory role applies to acute GVHD, we took advantage of SD-4 knockout (KO) mice.