The hierarchy of resistance to suppression described in this AIG

The hierarchy of resistance to suppression described in this AIG model has implications for the design

of Treg-based therapies in terms of which responses can be targeted effectively by Tregs, and which type of Tregs are most appropriate for the job. This was highlighted by a further study in this experimental system, which illustrated once again the additive effects of activation status and antigen specificity in determining the capacity of Tregs to modulate autoaggressive responses. Only antigen-specific (not polyclonal) iTreg can suppress the development of Th17-induced pathology in the gastritis model [96]. A similar pattern of responsiveness to Treg-induced suppression selleck chemicals has been observed in several other model systems. The ameliorative effect of all trans-retinoic acid treatment on the development of type 1 diabetes is dependent upon an expansion of FoxP3+

Tregs which suppress the generation of IFN-γ but not IL-17 responses [97]. We have found that Tregs isolated from the central nervous system (CNS) of mice with EAE suppress IFN-γ production efficiently by CNS-derived effector T cells in co-culture, but are unable to suppress their production of IL-17 [76]. Our own unpublished studies also suggest that polarized myelin-responsive Th17 populations are relatively resistant to Treg-mediated suppression of their proliferation in vitro, compared to their Th1 counterparts. GSK126 purchase Consistent data from human studies show that Th17 cells are resistant to Treg-mediated suppression at the level of proliferation [98], as well as cytokine production [99]. Extrapolation of these in vitro studies would suggest that Th17

cells might preferentially resist Treg-mediated control of their clonal expansion in vivo. As yet, this has not been Dimethyl sulfoxide tested formally. It therefore appears that Th1 responses are perhaps the most acutely sensitive to Treg-mediated suppression, while Th17 responses appear most resistant. The basis for differential sensitivity to regulation remains unclear. However, factors associated with Th17 responses (IL-6, IL-21, TNF-α and potentially IL-17 itself) impair the suppressive capacity of Tregs and may thus prevent suppression of Th17 responses selectively. Several studies have presented persuasive arguments that the suppressive function of Tregs must, at times, be subverted to allow inflammatory immune responses to effectively eliminate pathogens. Central to this hypothesis is the ability of the innate immune system to sense the presence of a pathogen via Toll-like receptor (TLR) signalling and respond by producing proinflammatory cytokines such as IL-6, which overcome Treg-mediated suppression [100]. IL-6 blockade has been shown to restrain the development of both Th1 and Th17 responses following immunization [101]. IL-6 influences the development and expansion of effector and Treg cell responses as well as Treg function, and this has been demonstrated most elegantly in the EAE model.

In the current study, for the first time, we demonstrated that le

In the current study, for the first time, we demonstrated that levamisole supplementation could also effectively improve the response rates of haemodialysis patients to tetanus vaccination. click here A high proportion of haemodialysis patients have been reported to have unprotective anti-tetanus antibody levels.[2, 14] Moreover, the response rates of these patients to Td vaccination have been reported to be significantly lower than healthy controls

because of impaired humoral and cellular immunity.[3-5] Because of this impaired seroconversion rate, it is recommended that haemodialysis patients should be monitored for antibody levels after tetanus vaccination and receive boosters if needed.[15] As shown in our study, levamisole could significantly enhance the response rate to tetanus vaccination in haemodialysis patients Ibrutinib clinical trial and may obviate the need for monitoring antibody levels after vaccination. Levamisole supplementation, in particular might be beneficial to haemodialysis patients who are unlikely to respond tetanus vaccination such as elderly, immunocompromised

or malnourished patients. However, our study had a small sample size and a short duration of follow-up. Because of these limitations, our results need to be confirmed in trials with larger sample sizes and longer durations of follow-up before any change in vaccination policy of haemodialysis patients could be made. Different protocols of levamisole therapy have been tried in the haemodialysis patients to enhance the seroconversion rate following HBV vaccination.

Sali et al.[12] reported that supplementing the HBV vaccination with 100 mg of levamisole after each haemodialysis session for 6 months was not superior to the placebo in enhancing the serconversion rate. However, Kayatas[8] found that supplementing the HBV vaccine with 80 mg of levamisole after each haemodialysis session for 4 months was significantly more effective in enhancing seroconversion rate compared with Dolutegravir chemical structure the placebo. Argani et al.[10] reported that the seroconversion rate in the patients who received HBV vaccination supplemented with daily 100 mg dose of levamisole for 6 days before and 6 days after vaccination was higher than the controls. Similarly, in our study, this 12-day protocol of levamisole supplementation was found to be more effective than placebo in enhancing the seroconversion rate following tetanus vaccination. The 12-day protocol of levamisole supplementation of vaccines is less costly and easier to follow. However, the efficacy of these different protocols for enhancing seroconversion following vaccination in haemodialysis patients should be further evaluated in larger studies. In our study, four patients (two from the levamisole and two from the placebo group) who were seropositive at 1 month post-vaccination became seronegative at 6 months.

All viruses belong to the Ad5 serotype On day 7, cultured DC wer

All viruses belong to the Ad5 serotype. On day 7, cultured DC were harvested, replaced at 1 × 106 cells/ml in serum-free RPMI 1640, and infected with adenoviruses at different multiplicities of infection (MOI) for 2 h (10, 25, 50, 100, and 200 MOI). Three hours later, complete RPMI 1640 were restored, and cells were cultured for another 2 days. DC were then washed

twice with complete medium before experiments. For pulsing with donor antigens, BN spleen cell lysate that was prepared by repeat freezing (5 min in dry ice–ethanol bath) and thawing (10 min in 37 °C warm bath) for 5 times, and added at 1/5 of DC/spleen cell (used to prepare lysate) ratio for the last 48 h of DC culture. Then, cells Tipifarnib in vivo were harvested, analysed by flow cytometer, and used as stimulators for mixed leucocyte reaction (MLR). Uninfected and Adv-0-DC served as control. To analyse gene check details expression of IKK2dn, RNA from AdV-0-DC and Adv-IKK2dn-DC was treated with DNase and reversely transcribed to cDNA. For IKK2dn polymerase chain reaction (PCR) analysis, the following primers were used: sense, 5′-GGCCTTTGAGTGCATCAC-3′ and antisense, 5′-CTCTAGGTCGTCCAGCGT-3′. All samples were run in triplicate. To assess the overall cDNA content, glyceraldehyde phosphate dehydrogenase (GAPDH) served as a housekeeping gene control. The following pair of primers was used for GAPDH: sense, 5′-GGAAGGTGAAGGTCGGAGTC-3′ and antisense, 5′-GTAGAGGCAGGGATGATGTTC-3′; The PCR was performed in a GeneAmp PCR System

2700 (Applied Biosystems Inc, Foster City, CA, USA) thermal cycler by 30 cycles of denaturization (94 °C, 30 s), annealing (55 °C, 30 s), and extension (72 °C, 1 min). Flow cytometry.  Expression of DC surface antigens was analysed by EPICS ELITE flow cytometer (Beckman-Coulter, Olopatadine Fullerton, CA, USA). Cell staining was performed as previously reported [16]; briefly, cells were stained with FITC or PE-conjugated mouse monoclonal antibodies anti-rat MHC class II, CD80 or CD86 after blocking non-specific binding with 10% vol/vol normal serum. FITC- or

PE-conjugated isotype-matched irrelevant mAbs were used as negative controls (all from Serotec Corp). Mixed lymphocyte reaction.  To maintain immature condition of DC, 7-day-cultured Lewis DC were infected with 25-100 MOI of AdV-IKK2dn. Adv-0-infected DC were used as control. To determine the antigen-presenting capacity of DC in vitro, MLR was performed with mitomycin C (MMC, 25 mg/ml for 30 min)-inactivated DC from different MOI groups as stimulators and nylon wool-purified Lewis or NB splenic T cells as responders. In Lewis T cell as responder cell experiments, Lewis DC pulsed with BN spleen cell lysate were used as stimulators, and DC not pulsed with alloantigen were used as control. The stimulator used was 3 × 102, 1 × 103, 3 × 103, and 1 × 104. Cultures were established in triplicate in 96-well round-bottom microculture plates (200 ul/well with 1 × 106 T cells) and maintained in complete medium for 72 h in 5% CO2 at 37 °C. MTT (0.

The role of PGE2 in mediating MSC suppressive effects on Th17 dif

The role of PGE2 in mediating MSC suppressive effects on Th17 differentiation DNA/RNA Synthesis inhibitor cultures was confirmed by addition of specific antagonists and agonists for candidate PGE2 receptors. IL-17A secretion by CD4+ T cells re-purified from MSC/Th17 co-cultures was restored to the

same level as that of control Th17 cultures by the highly selective EP4 receptor antagonist L-161,982 (Fig. 6C). Similarly, EP4 antagonism reversed the inhibition by MSCs of CD25 up-regulation on CD4+ T cells (data not shown). That this observation was specifically attributable to PGE2 produced by MSCs during co-culture was confirmed by transfer of conditioned media from FACS-sorted co-culture populations and relevant controls to fresh Th17 cultures in the presence or absence of EP4 antagonist (Supplementary Figs. S5, S6 and S7B). In this case, only medium conditioned by MSCs sorted from Th17/MCS co-cultures transferred a

Th17 suppressive effect that was reversible by EP4 antagonism. Experiments carried out with antagonists of the EP1 and EP2 receptors (SC-51322 and AH 6809 respectively) yielded negative results (data not shown). As further evidence of a specific role for PGE2/EP4, the EP4 agonist L-902,688-mediated dose-dependent inhibition of the primary induction of Th17 cells (Fig. 6D). Up to this point, the experiments were carried out exclusively with primary naïve and/or memory CD4+ T cells undergoing activation in vitro under PD98059 solubility dmso short-term Th17-skewing conditions. Making use of a unilateral ureteral obstruction (UUO) model in which we have previously reported intra-renal accumulation of effector-memory phenotype Th17 cells 22, it was determined

whether MSCs exert a mechanistically-similar Orotidine 5′-phosphate decarboxylase suppressive effect on the re-activation of committed Th17 cells from an area of ongoing tissue inflammation. As shown in Fig. 7A, B6 mice underwent UUO for 72 h following which CD45+ cells were enriched from obstructed and contralateral (non-obstructed) kidneys and briefly stimulated through the T-cell receptor in the absence or presence of MSCs. In-line with our previous findings 22, anti-CD3ε-stimulation was associated with robust secretion of IL-17A by cells from obstructed kidneys (Fig. 7B). The presence of MSCs was associated with dose-dependent reduction in IL-17A concentration following either 24 or 48 h culture periods. Qualitatively similar results were observed in a total of seven similar experiments with median proportionate inhibition of IL-17A production being 56% (range 19–69%) at MSC:CD45+ cell ratio of 1:20. As we have previously reported 22, IL-17A secretion was absent from stimulated cultures of CD45+ cells from non-obstructed kidneys (data not shown). The suppressive effect of MSCs was reversed by indomethacin (Fig. 7C). Thus, naturally occurring effector-memory Th17 cells undergoing activation through the T-cell receptor signalling complex are amenable to suppression by MSCs via a similar COX-2-dependent mechanism.

16 In the current study, AFLP was found to be useful for discrimi

16 In the current study, AFLP was found to be useful for discrimination between inter- and intrapatient isolates. Moreover, GSK126 in vivo all isolates could be identified down to the species

level according to the current taxonomic status. A majority of patients were exclusively colonised by one AFLP genotype. Only one genotype was shared between two patients. The colonisation of CF patients by multiple AFLP genotypes was already reported previously [37] but this study was performed in 2002, well before the recent taxonomical changes. Therefore, from the present perspective, we cannot appraise if intra- or interspecific variations were detected. Defontaine et al.37 state multiple colonisations with up to three different genotypes, comprising one predominant genotype associated with up to two accompanying genotypes. Exceptionally, in our study, we found patients colonised with up to five different genotypes over a period of up to 5 years, with re-appearing genotypes. Therefore,

it is very likely that those patients are colonised with multiple S. prolificans genotypes. Our data mirror that CF patients can be chronically colonised with a specific genotype or multiple genotypes for prolonged periods of time (several years). Co-colonisation by multiple genotypes, also in non-CF patients, has been recognised before for other fungal species, such as A. fumigatus and A. flavus.36,38,39 If multiple colonisation turns into multiple infections by different genotypes of one species, this might have an impact on disease outcome, check details as we found that different Scedosporium isolates from the same patient (Table 1) can vary considerably in their AFSP. In particular, when patients are colonised by two or more Megestrol Acetate isolates with different susceptibility patterns, this may result in an overestimation of MIC values. This situation is exemplified in this study for instance in patient 13 where one clinical sample contained an MICA-susceptible, as well as MICA-resistant isolate of the same species. Apparently,

also patient 1 was colonised at the same time with two isolates of the same species, but with different AFSPs. For this reason, clinical specimens should be carefully analysed for the possible presence of multiple strains expressing variable antifungal susceptibilities. Overseeing such mixed infections due to S. prolificans may in part explain the therapy refractive nature of S. prolificans. In conclusion, we found that S. prolificans represents the most prevalent Scedosporium species in the respiratory tract of CF patients and immunocompromised patients in Northern Spain. In CF patients, P. boydii or S. prolificans were exclusively found as respiratory colonisers. All patients were colonised over years exclusively with isolates affiliated to one Scedosporium species, but to multiple AFLP genotypes carrying variable AFSP.

TP53 missense mutations were detected in three of the p53 overexp

TP53 missense mutations were detected in three of the p53 overexpressed oligodendroglial tumors studied. Our results suggest that 1p loss is almost specific to oligodendroglial tumors. Although the prediction of 1p status based solely on the morphologic features seems to be difficult, the immunohistochemistry for p53 is a useful tool in that p53 overexpression is closely related to the 1p-intact status in oligodendroglial tumors. “
“Autophagy is a dynamic process of protein degradation.

Induction of autophagy by temozolomide (TMZ) has been noted in glioma cell lines. Twenty-eight specimens, obtained from 14 patients before and after TMZ treatment, were analyzed to investigate whether induction of autophagy could be detected learn more in surgical specimens by immunohistochemical analysis. Macroautophagy was monitored by immunohistochemical analysis employing anti-light chain 3 isoform B (LC3B) and anti-lysosome-associated membrane protein 1 (LAMP1) antibodies; chaperone-mediated autophagy was monitored by anti-LAMP2A antibody immunostaining. Furthermore, detection of LC3B protein by Western blotting was performed on six specimens obtained from the preserved

frozen tissues of three patients. All specimens showed dot-like staining for each immunostain in the cytoplasm of glioma cells, indicating induction of autophagy. LC3B, LAMP1 and LAMP2A immunostains were semiquantitatively scored from 1 to 3 points. Combination Saracatinib solubility dmso of the three scores after TMZ treatment (6.4 ± 1.2) showed a significant increase (P = 0.020) compared to pre-treatment scores (5.2 ± 1.5). Western blotting for LC3B showed increased LC3B-I and LC3B-II expression after TMZ treatment. The present study proved that autophagy monitoring by immunohistochemical

staining of surgical specimens was feasible. These results suggest that autophagy is induced Chloroambucil by TMZ. “
“J. Attems, K. Jellinger, D. R. Thal and W. Van Nostrand (2011) Neuropathology and Applied Neurobiology37, 75–93 Sporadic cerebral amyloid angiopathy Cerebral amyloid angiopathy (CAA) may result from focal to widespread amyloid-β protein (Aβ) deposition within leptomeningeal and intracortical cerebral blood vessels. In addition, pericapillary Aβ refers to Aβ depositions in the glia limitans and adjacent neuropil, whereas in capillary CAA Aβ depositions are present in the capillary wall. CAA may cause lobar intracerebral haemorrhages and microbleeds. Hypoperfusion and reduced vascular autoregulation due to CAA might cause infarcts and white matter lesions. CAA thus causes vascular lesions that potentially lead to (vascular) dementia and may further contribute to dementia by impeding the clearance of solutes out of the brain and transport of nutrients across the blood brain barrier. Severe CAA is an independent risk factor for cognitive decline. The clinical diagnosis of CAA is based on the assessment of associated cerebrovascular lesions.

We recently reported that mast cells bearing mutations in three t

We recently reported that mast cells bearing mutations in three tyrosine residues (Y219F/Y225F/Y229F)

of the ITAM of the FcεRI β-chain (FcRβ) failed to degranulate upon cross-linking of FcεRI with low-dose antigen 18. In this context, FcRβ-ITAM positively controls FcεRI-mediated mast cell degranulation. In the present study, to elucidate underlying mechanisms of degranulation elicited by costimulation with low-dose antigen and adenosine, we employed FcRβ-ITAM mutant cells. The findings of the present study indicate indispensable roles of FcRβ-ITAM in the regulation of synergistic degranulation response upon costimulation with low-dose antigen and adenosine, possibly reflecting in Fluorouracil manufacturer vivo allergic reactions. First, we examined amplifying effects of adenosine on release of β-hexosaminidase, one of the intragranullar enzymes, from BM-derived C59 wnt mouse mast cells (BMMC) in response to FcεRI stimulation. As shown in Fig. 1A, adenosine increased β-hexosaminidase release from BMMC sensitized with anti-TNP IgE (IgE-3), when the dose of TNP-BSA was so low (0.1 ng/mL) as

to fail to induce degranulation by cross-linking of FcεRI. Next, we examined the enhancing effects of adenosine on degranulation elicited by a well-known house dust mite allergen, dermatophagoides farinae (Derf) in BMMC sensitized with Non-specific serine/threonine protein kinase anti-Derf IgE. Figure 1B shows that adenosine increased release of β-hexosaminidase upon engagement of FcεRI with IgE and extracts of Derf, indicating that adenosine efficiently increases the degranulation

response even when the dose of synthetic antigen or natural allergen was as low as threshold. To elucidate the physiological relevance of Ca2+ influx for degranulation response synergistically induced by low-dose antigen (0.1 ng/mL) and adenosine, we examined β-hexosaminidase release under Ca2+-saturated or Ca2+-free conditions. Degranulation assay was performed in Ca2+-free medium containing 1 mM EGTA for complete depletion of extracellular Ca2+ and 10 μM 1,2-bis(o-aminophenoxy)ethane-N,N,N′,N′-tetraacetic acid-tetra (acetoxymethyl) Ester; (BAPTA-AM) was employed as a chelator of intracellular Ca2+. Under extracellular Ca2+-free conditions, β-hexosaminidase was not released from BMMC stimulated with low-dose antigen and adenosine (Fig. 2A), indicating that Ca2+ influx is indispensable for the synergistic degranulation response. Thus, we next evaluated the effects of adenosine on the mobilization of intracellular calcium ([Ca2+]i) in response to antigen stimulation. Figure 2B shows that adenosine greatly amplified [Ca2+]i mobilization, when added to IgE-loaded mast cells together with low dose of antigen.

1% BSA and incubated with equal volume of 1 25 μM CFSE (Molecular

1% BSA and incubated with equal volume of 1.25 μM CFSE (Molecular Probes Europe, Leiden, The Netherlands) for 10 min at room temperature. Unbound dye was quenched by the addition of equal volume of RPMI+10% FBS and 15 min incubation at 37°C. CFSE-labeled CbT cells were washed twice in RPMI+10% FBS and plated at 5×104 cells/well in 96-well round-bottom plate (Corning, Corning, NY, USA). mDC incubated for 24 h with isotype-matched control mAb (MOPC-21), anti-CD300e (UP-H2) mAb or stimulated with LPS at 100 ng/mL were collected and plated over the CbT at ratios

(CbT:mDC) 10:1; 20:1; 40:1; 80:1 and 160:1. After 4 days samples were examined by flow cytometry for sequential dilution of CFSE fluorescence and analyzed using FlowJo software GSI-IX datasheet (Three Star). FlowJo Proliferation Platform was used to analyzed CbT-cell proliferation expressing BAY 80-6946 the results as “% divided” that is defined as the percentage of CbT cells in the starting population that divided (assuming that no cells died in culture). Statistical analysis was performed using either the Student’s t-test or the non-parametric Kolmogorov–Smirnov test. This work was supported

by a grant from Plan Nacional de I+D (SAF2007-61814) and Red Heracles, Ministerio de Ciencia e Innovación (MICINN). TB is supported by a fellowship from MICINN. BPC is supported by grant FI 07/00054 and FEB by contract CES 07/015 both from Instituto de Salud Carlos III. The authors thank Marta Donini (University of Verona, Verona, Italy) for technical advice in monocyte manipulation and Dr. Oscar Fornas (University Pompeu Fabra, Barcelona, Spain) for advice in flow cytometry analysis. They are very grateful to Marco A. Fernández (Germans Trias and Pujol Health Sciences Research Institute, Badalona, Spain) for the support in mDC isolation.

They thank Gemma Heredia (University Pompeu Fabra, Barcelona, Spain) for technical support in checking the specificity of UP-H mAb on CD300 transfectants. They also thank blood donors for their contribution. Conflict of interest: The authors declare no financial or commercial conflict of interest. “
“The obligate intracellular bacterium PRKACG Parachlamydia acanthamoebae is a potential human pathogen, but the host range of the bacteria remains unknown. Hence, the growth of P. acanthamoebae Bn9 in protozoa (Tetrahymena, Acanthamoeba, Dictyostelium) and mammalian cells (HEp-2, Vero, THP-1, PMA-stimulated THP-1, Jurkat) was assessed using an AIU assay which had been previously established by the current authors. P. acanthamoebae grew in Acanthamoeba but not in the other cell types. The growth was also confirmed using DAPI staining, FISH and TEM. These results indicate that the host range of P. acanthamoebae is limited. Parachlamydia acanthamoebae is an environmental chlamydia of the order Chlamydiales. It is an obligate intracellular bacterium that is widely distributed in the natural environment, including in rivers and soil (1).

All models included a random effect at the individual level to ac

All models included a random effect at the individual level to account for the within-individual correlation of titre measurements at different time points. Geographical clustering of parasite prevalence, antibody prevalence or age-adjusted antibody density was assessed as described previously [18, 19] using satscan software on binary (Bernouilli model) or continuous (normal model) variables (, Accessed 2 February 2012). A total of 509 individuals

were enrolled in the longitudinal study; 249 children ≤5 years of age, 126 children between 6 and 10 years of age and 134 adults who were ≥20 years (Table 1). The overall P. falciparum parasite prevalence by microscopy at enrolment was 38·1% (194/509). Microscopic P. falciparum parasite prevalence was significantly higher in children SB203580 6–10 years of age compared with younger children (P = 0·002) and lowest in adults (P < 0·001); parasite density in parasitaemic individuals decreased with age (test for trend between age groups, P = 0·012). Baseline P. falciparum parasite prevalence by PCR was 57·1% (284/493) and showed the same age-pattern as microscopically detectable parasite carriage, that is, higher in children 6–10 years compared with younger children (P < 0·001) and lowest in adults (P = 0·002). As expected, given that all participants were given curative antimalarial therapy at enrolment, P. falciparum

parasite prevalence decreased during the study in all age groups (Figure 1). During the last cross-sectional survey, none of the adults had microscopically detectable infections, but 14·2% (16/113) had submicroscopic P. falciparum infections. We found no evidence for geographical clustering of parasite carriage at any time point (data not shown). We evaluated the prevalence and titre of antibodies against P. falciparum AMA-1,MSP-119, MSP-2,

and CSP and against An. gambiae salivary protein gSG6. The baseline prevalence of antibodies to MSP-119, MSP2 and CSP all increased with increasing age group (P < 0·001). Prevalence of anti-AMA-1 antibodies showed an initial increase and then decrease with age; antibody prevalence was higher in 6- to 10-year-old children compared with younger children (P < 0·001) and compared with adults (P = 0·005). Phosphatidylinositol diacylglycerol-lyase Antibody titre increased with increasing age group for MSP-119, MSP-2 and CSP (P ≤ 0·009; Figure 2, Table 1). AMA-1 antibody titre was again higher in 6- to 10-year-old children compared with younger children (P < 0·001) and adults (P < 0·001). Baseline anti-gSG6 antibody prevalence showed a borderline significant increase with age (P = 0·053); antibody titre increased significantly with age (P = 0·004). We found no evidence for geographical clustering of the prevalence or age-adjusted titre of antibodies against any of the antigens at any time point (data not shown).

3), indicating that in these coculture assays, inhibition of resp

3), indicating that in these coculture assays, inhibition of responder cell proliferation by CD8+CD39+ T cells is not the result of cytotoxicity. In this study, we describe for the first time the expression of, and a functional role for, CD39 on human pathogen activated CD8+ Treg cells. CD8+CD39+ T cells from

PPD-responsive individuals specifically co-expressed the known classical Treg-cell markers CD25, Foxp3, LAG-3, and CCL4. To assess if CD39 expression was merely a marker of CD8+ Treg cells or was directly involved in the CD8+CD39+ T cell’s suppressive activity, we purified CD8+CD39+ T cells, and showed that they were Ridaforolimus mouse strongly enriched for suppressive activity and the expression of Treg markers, and that both the chemical CD39 antagonist, ARL, as well as a blocking anti-CD39 antibody were able to partly inhibit Nutlin 3a the suppressive activity of CD8+CD39+ T cells. Altogether these data indicate that CD39 is a marker for regulatory CD8+ T cells

and that CD39 contributes functionally to the suppression mediated by human CD8+CD39+ T cells. Both ARL as well as the blocking anti-CD39 antibody only partly inhibited suppressive activity, indicating that also other mechanisms may contribute to suppression. We previously demonstrated the expression of LAG-3 and the functional involvement of CCL4 in immune regulation by BCG-activated CD8+ Treg cells. In the current study, ≥43% of CD8+CD39+ T cells also expressed CCL4, while we did not find any expression of IL-10 on these T cells. CD8+ Treg cells have been described in human Mycobacterium-infected LNs [8] and lepromatous lesions [9, 10], demonstrating that CD8+ Treg cells are present at the site of disease and suggesting a potential role for these cells in disease pathogenesis. In line with our previous studies showing that BCG activated CD8+ Treg cells in PPD-responsive individuals, but not in donors

that Sulfite dehydrogenase did not recognize PPD in vitro [10], also in the current study CD8+CD39+ Treg cells were confined to PPD responders, suggesting that these cells originated from preexistent antigen-specific memory T cells. We have previously hypothesized that Treg cells could contribute to the relative failure of BCG vaccination in conferring protection against pulmonary TB in adults [6]. In TB, recent results have suggested a role for Th17 cells both in protection and pathology. IL-17 producing CD4+ T cells in the lung, induced by BCG vaccination, were associated with protective immunity to TB in mice [2, 38]; interestingly, in human tuberculous pleural effusions, the number of CD4+CD39+ Treg cells was inversely related to the number of Th17 cells, and CD39+ Treg cells suppressed the differentiation of naïve CD4+ cells into Th17 cells [39]. Frequencies of CD4+CD39+ T cells correlated negatively with IL17A responses in stimulated PBMCs after MVA85A vaccination [40].