Therefore, to address whether the lack of the two different class

Therefore, to address whether the lack of the two different classes of HRs have an intrinsic effect on cytokine production or differentiation of CD4+ T cells, we stimulated purified CD4+

T cells from the spleen and lymph nodes of naïve B6, H1H2RKO, and H3H4RKO mice with plate bound anti-CD3 and soluble anti-CD28 mAbs and screened the culture supernatants for IL-17, IFN-γ, IL-4, and IL-2 production by enzyme-linked immunosorbent assay (ELISA) at 24, 48, and 72 h. IL-17 was undetectable among the three strains. Interestingly, across the time points examined, LY294002 manufacturer CD4+ T cells from H3H4RKO mice produced significantly more IFN-γ compared with cells from H1H2RKO and B6 mice (Fig. 4A). In addition, IL-4 production by stimulated H1H2RKO CD4+ T cells was significantly

greater than that of CD4+ T cells from H3H4RKO and B6 mice, which was undetectable (Fig. 4B). Among the strains, we observed no significant difference in the production of IL-2 by CD4+ T cells (Fig. 4C). These results indicate that CD4+ T cells from H3H4RKO have an inherent bias toward IFN-γ production, while H1H2RKO are predisposed to produce IL-4. Therefore, the lack of H1R-H2R and H3R-H4R predisposes CD4+ T cells to differentiate into either Th2 or Th1 cells, respectively, and may account for the altered cytokine production and differences in disease severity seen among the strains of mice. The severity of EAE observed in H1H2RKO and H3H4RKO parallels NVP-AUY922 that of

the respective individual receptor knockout (KO) mice in that clinical EAE is less severe in both H1RKO and H2RKO mice and more severe in H3RKO and H4RKO mice. Similarly, EAE pathology was significantly less in H1R, H2R and H1H2RKO mice, whereas it was significantly greater in H3RKO, H4RKO, Edoxaban and H3H4RKO mice. The basis of this effect may be due to a compensatory upregulation of the remaining HRs in single HRKO, H1H2RKO, and H3H4RKO mice. With respect to T cells, we showed that HR expression is rapidly downregulated upon T-cell receptor activation, and HR signaling associated with CD4+ T-cell differentiation and effector functions occurs during initial activation [[31]]. Therefore, we compared HR expression in naïve CD4+ T cells of single HRKO, H1H2RKO and H3H4RKO mice by quantitative real-time polymerase chain reaction (qRT-PCR). H3R expression was undetectable in naïve CD4+ T cells from all single HRKO and H1H2RKO mice. Interestingly, in the absence of single HRs, the expression of the remaining HRs was increased above B6 levels in naïve CD4+ T cells (Fig. 5A). Moreover, H4R expression was increased in H1RKO, H2RKO, and H1H2RKO mice with H1RKO

Diameters were determined for n = 72 beads and were 136 µm (range

Diameters were determined for n = 72 beads and were 136 µm (range 74–205 µm) for LB and 40 µm (range 15–85 µm) for SB (Fig. 1a). Using the formula for sphere volume = 4/3 ×π×r3, the LB were found to have a mean volume of 1 317 000 µm3 compared to 34 000 µm3 for the SB, giving a ratio difference in volume of 38·7 between LB and SB. Using the formula for sphere surface area = 4 × p ×r2, the LB were found to have a surface area of 58 107 mm2 compared to 5027 mm2 for the SB, giving a ratio difference in surface area of 11·6 between selleck screening library LB and SB. Because both groups received the same amount of bacteria and alginate, this provides a larger total surface area of the SB of 3·3 (38·7/11·6 = 3·3).

In addition, the volume of alginate in the two bead suspensions was adjusted to ensure equal volumes of alginate in the two groups. At day 1 after challenge, a significantly higher number of CFUs was observed in the lungs of SB group compared to the LB group (P < 0·003) (Fig. 2). At days 3, 5 and 6 no significant differences in quantitative bacteriology were observed between the two groups. P. aeruginosa could be cultured from the majority of mice at all time-points (Fig. 2). Four mice from each group were killed 2 h after infection, and lungs examined for

number of CFUs to confirm that the infection dose was equal in the two groups. No significant differences were observed in CFUs 2 h after challenge (Fig. 2). As expected, a PMN-dominated AZD6244 inflammation was observed in all mice at day 1 after infection (Table 1). However, in the SB group the inflammation was located exclusively endobronchially, in contrast to a partially mixed localization in the LB group (Table 1). In the SB group this shifted

significantly to a mixed localization or exclusively parenchymal localization on days 2/3 after challenge (P < 0·005, Table 1), and in general was paralleled by a more peripheral presence of the bacteria in the alveoli of the SB group. For the SB group, a significantly faster resolution of inflammation at days 5/6 compared to the LB group was observed (P < 0·03, Table 1). For both groups together, a significant increase in degree of inflammation from day 1 to days 2/3 was observed (P < 0·01, Table 1). However, the difference between the two groups for this observation did not reach significance. Ergoloid The area of the biofilm-like structures identified by Alcian blue staining were significantly smaller in the SB group compared to the LB group at day 1 and days 2/3 (P < 0·001, Figs 3 and 4). In accordance, the area of the airways in which biofilm-like structures were identified were significantly smaller in the SB group compared to the LB group at days 2/3 (P < 0·002, Figs 3 and 4). The number of identified biofilm-like structures was 137 in the LB group versus 308 in the SB group. PNA-FISH and DAPI staining confirmed the presence of P. aeruginosa in the biofilm-like structures (Fig. 5).

It could, therefore, be hypothesized

that P gingivalis m

It could, therefore, be hypothesized

that P. gingivalis modulate T-cell development and function in ways that promotes Th17-mediated inflammation ZD1839 cost over a Th1-dependent cell-mediated immune response, which is thought to promote clearance of P. gingivalis [60]. Numerous Th17 cells can be observed in periodontitis lesions [93] and can function as an osteoclastogenic subset that links T-cell activation to inflammatory bone loss [98, 99]. On the other hand, Th1 cells are thought to play a protective role in periodontitis [100], although some studies have attributed destructive effects to Th1 cells [101]. Overall, more research is warranted to better understand the roles of T-cell subsets in periodontitis and the biological relevance of their modulation by P. gingivalis in the context of its role as a keystone pathogen. In inflammatory conditions associated with bacterial communities, traditional concepts of pathogen selleck chemical and commensal have become obsolete. This is well illustrated by periodontal disease where P. gingivalis can remain quiescent for long periods of time before (and after)

expressing pathogenicity through manipulation of the host response and disruption of homeostasis. Conversely, organisms usually considered commensals, such as S. gordonii, can act as accessory pathogens and elevate the pathogenicity of P. gingivalis. Commensal organisms can also act as pathobionts, i.e. following homeostasis breakdown and initiation of inflammation, these commensals-turned pathogens can propagate and amplify destructive periodontal inflammation. In this regard, a recent study identified a bacterium (designated NI1060) in the murine oral cavity that selectively accumulates in damaged periodontal tissue and causes inflammatory

bone loss by activating the intracellular PRR Nod1 [102]. NI1060 appears to thrive Dichloromethane dehalogenase under inflammatory conditions, apparently because it can readily procure nutrients derived from tissue breakdown in an inflammatory environment. NI1060, moreover, contributes to the exacerbation of inflammation by inducing neutrophil-specific chemokines, thereby augmenting neutrophil infiltration in the periodontal tissue [102]. Other commensals (NI440 and NI968) dominate exclusively in healthy sites and do not behave as periodontal pathobionts [102]. The notion that there are pathobionts that can opportunistically contribute to periodontitis is consistent with recent metagenomic studies showing a strong association of previously underappreciated bacteria (including the gram-positive Filifactor alocis and Peptostreptococcus stomatis and other species from the genera Prevotella, Megasphaera, Selenomonas, and Desulfobulbus) with periodontitis [8, 103, 104]. Moreover, as the bacterial biomass increases with increasing periodontal inflammation, the ecological shift from health to disease involves the emergence of newly dominant community members as opposed to the appearance of novel species [8].

Different automated immunostaining systems showed similar results

Different automated immunostaining systems showed similar results. 21 of 186 samples had nuclear accumulation in ≥5% of cells, 17 samples showed <5% ß-catenin positive nuclei. None of these 17 cases had CTNNB1 mutations, but 18 of 21 cases with ≥5% accumulation did, identifying these 18 cases as Wnt-subgroup medulloblastomas. 15 of 18 mutated cases showed monosomy 6, 3 had balanced chromosome 6. On the contrary, none of the CTNNB1 wildtype tumors had monosomy 6. Standard neuropathological evaluation of medulloblastoma samples should include

IHC of ß-catenin because tumors with high nuclear accumulation of ß-catenin most probably belong to the Wnt subgroup of medulloblastomas. Still, IHC alone may be insufficient to detect all Wnt cases. Similarly, chromosome 6 aberrations were not present in all CTNNB1-mutated cases. Therefore, we conclude that sequencing analysis

of CTNNB1 exon RAD001 supplier 3 in combination with ß-catenin IHC (possibly as pre-screening method) is a feasible and cost-efficient way for the determination Pifithrin-�� research buy of Wnt medulloblastomas. “
“Pineal parenchymal tumors (PPTs) are rare neoplasms which occupy less than 1% of primary CNS tumors. Because of their rare incidence, previous reports on PPTs are limited in number and the useful molecular markers for deciding histological grading and even selecting chemotherapy are undetermined. In this study, we conducted immunohistochemical

analysis of 12 PPT specimens, especially for expression of O6-methylguanine DNA methyltransferase (MGMT) to assess whether temozolomide (TMZ) could serve as a possible alternative therapy for PPTs. We analyzed 12 PPTs, consisting of three pineocytomas, six PPTs of intermediate differentiation (PPTIDs), and three pineoblastomas. 2-hydroxyphytanoyl-CoA lyase Immunohistochemical analysis was performed using antibodies against MGMT, synaptophysin, neurofilament protein (NF), p53, and neuronal nuclear antigen (NeuN). Immunohistochemically, 11 out of 12 cases were positive for MGMT. The mean MIB-1 labeling index was less than 1% in pineocytoma, 3.5% in PPTID, and 10.5% in pineoblastoma. All 12 cases were positive for synaptophysin and 11 cases, except one PPTID case, showed positive for NF. Nuclear staining of NeuN was negative in all cases although cytoplasmic staining of NeuN was observed in five cases. No case was positive for p53. Eleven out of 12 cases of PPTs demonstrated MGMT expression, suggesting chemoresistancy to TMZ treatment. This is the first report showing MGMT expression in PPTs. In addition, MIB-1 labeling index correlated with WHO grade, although the immunoreactivity of synaptophysin, NF, NeuN and p53 did not correlate with the histological grade. “
“A. Morancho, L. García-Bonilla, V. Barceló, D. Giralt, M. Campos-Martorell, S. Garcia, J. Montaner and A.

aeruginosa and S aureus grown in a flow-chamber system We demon

aeruginosa and S. aureus grown in a flow-chamber system. We demonstrated how adaptive mutations in regulator genes of P. aeruginosa affect interactions between P. aeruginosa and S. aureus in co-culture biofilms. Pseudomonas aeruginosa

wild-type PAO1 (Holloway & Morgan, 1986), P. aeruginosa mucA mutant (Hentzer et al., 2001), DMXAA research buy P. aeruginosa rpoN mutant (Webb et al., 2003), P. aeruginosa pilA mutant (Klausen et al., 2003b), P. aeruginosa pilH mutant (Barken et al., 2008), P. aeruginosa pqsA mutant (D’Argenio et al., 2002), S. aureus MN8 (Yarwood et al., 2004), S. aureus ISP479 (Toledo-Arana et al., 2005) and S. aureus 15981 (Toledo-Arana et al., 2005) were kindly provided by the cited authors and used in the present study. The pDA2 plasmid (An et al., 2006) was used Selleckchem PD98059 to complement the pilA mutant. Fluorescence-tagged strains were constructed by the insertion of a mini-Tn7-eGFP-Gmr cassette as described (Koch et al., 2001; Klausen et al., 2003b). Escherichia coli strains MT102 and DH5α were used for standard DNA manipulations. Luria–Bertani medium (Bertani, 1951) was used to cultivate E. coli strains. A modified FAB medium (Qin et al., 2007) supplemented with 0.3 mM glucose and 3% of Tryptic Soy Broth (TSB, BD Diagnostics) was used for biofilm cultivation. Selective media were supplemented with ampicillin (100 mg L−1), gentamicin (60 mg L−1) or carbenicillin

(200 mg L−1). Biofilms were grown in flow chambers

with individual channel dimensions of 1 × 4 × 40 mm at 37 °C. The flow system was assembled and prepared as described previously (Sternberg & Tolker-Nielsen, 2006). Overnight cultures of P. aeruginosa and S. aureus were diluted to an OD600 nm of 0.001. The flow chambers were inoculated by injecting 350 μL of monospecies diluted cultures or P. aeruginosa–S. aureus 1 : 1 mixed-species diluted cultures into each flow channel with a small syringe. After inoculation, flow channels were left without flow for 1 h, after which medium flow (0.2 mm s−1) was started using a Watson Marlow 205S peristaltic pump. For DNase I treatment, biofilm medium was supplemented with 20 μg mL−1 bovine DNase I (Sigma) from the beginning of cultivation. All microscopic observations and image acquisitions were performed using a Zeiss LSM 510 confocal laser scanning microscope (Carl Zeiss, Jena, Lck Germany) equipped with detectors and filter sets for monitoring of green and red fluorescence from general nucleic acid staining SYTO 9 (Invitrogen) and gram-positive specific staining hexidium iodide (Invitrogen) (Mason et al., 1998), respectively. BacLite Live/Dead viability stain (Molecular Probes, Eugene, OR) was used to visualize dead and live cells in co-culture biofilms. Images were obtained using a × 40/1.3 objective. Simulated three-dimensional images and sections were generated using the imaris software package (Bitplane AG, Zürich, Switzerland).

The sequences of these genes were identical in the parental strai

The sequences of these genes were identical in the parental strains of 18A and PAO1 and their dispersal isolates (data not shown). Mutations may be mediated by other genes, such as the recombinase systems encoded by xerD and sss (Martinez-Granero et al., 2005), or through the action of lytic phage, the appearance of which correlates with the appearance of variants from biofilms of P. aeruginosa (Webb et al.,

2004; Rice et al., 2009). Alternatively, variant formation may be the result of growth phase–dependent expression of DNA repair systems, as is the case for low-level expression of the methyl-directed mismatch repair genes during stationary-phase growth in E. coli (Feng et al., 1996). The mutation frequency of the biofilm population decreased for both strains 18A and PAO1 during

the period when the biofilm biomass selleck products was increasing the fastest. It would therefore be of particular interest to quantify the expression of repair and recombination genes Dabrafenib at different stages of biofilm development. Similarly, sequencing of the genes encoding AHL synthetases (lasI and rhlI) and their cognate receptors (lasR and rhlR), as well as regulatory genes such as mvaT and vfr that are known to influence QS, revealed no mutations between the variants and the parent (data not shown). Therefore, changes in the expression of those genes and the subsequent production of AHL signals must be the result of mutations elsewhere in the genome. It has been shown that low protease production in clinical isolates could be complemented by overexpressing regulatory genes, and therefore, it is possible that the mutations lie in regulatory regions rather than in the genes encoding AHL synthesis or elastase production (Tingpej et al., 2007). In summary, the PAK6 results presented here show that increased diversification occurs in P. aeruginosa when it grows as a biofilm rather than planktonically. This was shown for both a representative CF chronic infection isolate and

the laboratory strain PAO1. Longitudinal studies of CF isolates from chronically colonised individuals have suggested that infecting strains evolve to a chronic infection phenotype characterised by the loss of acute virulence determinants (Smith et al., 2006a; Rau et al., 2010). Acute infection phenotypes are, however, seen during exacerbations of disease. Here, we have shown that some clinical strain variants regain hallmarks of an acute infection isolate when grown as a biofilm in vitro but not when grown as a planktonic culture. We propose that by perpetuating this cycle and leading to diversification in traits that may enhance survival in differing niches, biofilm growth increases in vivo survival and persistence resulting in intractable infection.

9 Unfortunately, the measurement of UPC cannot be standardized be

9 Unfortunately, the measurement of UPC cannot be standardized because urine protein is composed of variable proportions of albumin and other proteins.18 Dip-stick proteinuria correlates poorly with ACR,22,23 while PCR correlates reasonably well with ACR.24 Proteinuria of 0.5 g/day or more usually signifies macroalbuminuria.1,4 However, there have been no studies on the direct comparison between proteinuria and albuminuria in CKD in terms of utilities (biomarker, surrogate end-point and cost-effectiveness). Thus, any comparison between proteinuria and albuminuria in CKD is subject to problems inherent in indirect comparisons.25 Proteinuria and

albuminuria are good biomarkers (Table 1) because they predict clinical end-points (CV events, renal events or mortality) see more in both diabetic and non-diabetic patients.2,3 However, there must be three general lines of evidence to support the acceptance of a biomarker to be a surrogate end-point: biological plausibility, epidemiological data and RCT.3 Despite ample evidence in biological plausibility and epidemiological data, there are limitations in RCT regarding the validity of proteinuria or albuminuria as a surrogate end-point.3 For example, a secondary analysis (but not a primary analysis) of

the Modification of Diet in Renal Disease (MDRD) study indicated that a low BP target slows the GFR decline only in patients with proteinuria of 3 g/day or more.26 Similarly, a secondary analysis of the Prevention find more of Renal and Vascular End-stage Disease Intervention Trial (PREVEND-IT) found that BP lowering decreases CV events only

in patients with higher albuminuria levels.27 The Ongoing Telmisartan Alone and in Combination with Ramipril Global End-point Trial (ONTARGET) study even found that combined ACEI and ARB therapies decrease ACR while increasing renal outcome.3 Moreover, there has only been one renoprotective RCT with proteinuria as a treatment target to show that a reduction in proteinuria by titrated ACEI decreases tuclazepam renal end-points.28 Unfortunately, there have been no RCT with head-to-head comparisons between proteinuria and albuminuria.2 However, a change between normoalbuminuria and macroalbuminuria may be a surrogate for the development or remission of early diabetic nephropathy (Table 1).3 The remission of nephrotic proteinuria is a surrogate for the remission of GFR decline (Table 1).3 Moreover, ACEI- or ARB-induced change in proteinuria or albuminuria is a surrogate for changes in CKD progression in patients with mild to moderate proteinuria (Table 1).3 A randomized trial comparing screening for proteinuria and albuminuria is the best evidence of cost-effectiveness, but modelling is an alternative.29 However, most modelling approaches estimate effectiveness from traditional RCT, which are designed for testing efficacy and are not suitable for cost-effectiveness studies.

We saw no significant decline in PUFA levels related to immunizat

We saw no significant decline in PUFA levels related to immunization or challenge in the DTH model, except for arachidonic acid in the control group, even though footpad swelling in individual animals

correlated positively with reductions in serum EPA levels during the challenge phase. Evidently, the Th1-mediated inflammation did not consume the same amounts of fatty acids as the Th2-mediated inflammation. This could be explained by the difference in the size of the organs assessed in the two models – paws in the DTH model compared with the entire respiratory system in the airway model. Another possibility is that Th2-driven inflammation consumes large amounts of fatty acids because eosinophils are versatile producers of products from unsaturated fatty acids [24]. Further, we observed a reduction of high throughput screening compounds PUFA levels concomitant with immunization with a Th2-promoting adjuvant (alum), but not alongside Roxadustat cost immunization with a Th1-promoting adjuvant (Freund’s complete adjuvant). Th1 immunity was actually accomplished by an increase in serum arachidonic acid and DHA levels after immunization. The consumption of PUFAs during the Th2- but not the Th1-sensitization phase opens

the possibility that lipid mediators formed from PUFAs participate in producing the outcome of the interaction between the antigen-presenting cell and the naive T cell, in a way leading to Th2 cell maturation. The mechanisms can only be speculated upon and need further investigation. PUFAs affect gene transcription factors [25], production of prostaglandins and related mediators and affect thrombocyte activation and coagulation, processes that are linked intimately to inflammation Methisazone and immunity [26]. In conclusion, our results demonstrate clearly the complexity of the immunomodulatory effects of PUFAs and point to the importance of a clear definition of the type of immune reaction involved before testing PUFA supplementation as a preventive or disease-modulatory treatment. PUFA supplementation could probably be of significance to patients suffering from Th1-mediated

food allergies. However, at present we cannot draw conclusions concerning effects of PUFA supplementation on patients suffering from allergies that are complex mixtures of Th1 and Th2 immune reactions. This work was supported by the Swedish Research Council for Environmental, Agricultural Sciences and Spatial Planning (FORMAS), Food and Health Concept Center, Swedish Nutrition Foundation and Swedish Research Council, Gothenburg, Sweden. The authors declare no financial or commercial conflicts of interest. “
“Department of Clinical Research, Hamdard University, New Delhi, India In T-cell-mediated autoimmune diseases of the CNS, apoptosis of Fas+ T cells by FasL contributes to resolution of disease. However, the apoptosis-inducing cell population still remains to be identified.

However, the time of onset and whether the appearance of such shu

However, the time of onset and whether the appearance of such shunts varies between uncomplicated and complicated pregnancies are, to the best of our knowledge, not known. The circulatory pattern shows heterogeneity among mammals; for example each mouse placenta is supplied by distinct arterial inputs from the main uterine and uterine branch of the ovarian arteries that do not mix prior to their entry into the placenta [64]. A simplified drawing of the uterine arterial pattern in humans

and rodents is shown for reference in Figure 2. In primates and rodents, the two uterine arteries may not contribute equally to PF-02341066 mw uteroplacental blood flow, with the predominance of one uterine artery over the other varying in normal vs. complicated human pregnancy [63, 32, 7]. In women, uterine artery diameter rises linearly through the first 16 weeks of pregnancy [17], doubling by mid-gestation and increasing cross-sectional area fourfold. Because extravillous trophoblasts plug the spiral artery lumens before the 10th week of gestation, the increase in uterine artery diameter begins well before trophoblast-mediated

reductions in downstream vascular resistance selleck chemicals llc occur. The presence of arteriovenous anastomoses may be contributory to the early rise in uterine artery blood flow, although to our knowledge serial studies documenting their time course have not been done. Nonetheless, the increase in uterine artery diameter appears to be the major factor raising uteroplacental blood flow during the first half of gestation, with the blood-flow rise during the second half of pregnancy being due to greater flow during diastole, increased flow velocity throughout the cardiac cycle, and a continued increase

in vessel diameter [61, 17, 6, 30, 78]. Of interest, the rise in uterine artery blood flow fails to keep up with the much faster increases in fetal weight late in gestation [66], suggesting that Endonuclease uterine arteriovenous oxygen extraction is increased to maintain oxygen delivery. The increase in uterine artery diameter occurs through a combination of vascular remodeling and vasodilation. The remodeling reflects both cellular hyperplasia and hypertrophy (at least of vascular smooth muscle [13, 1]) and varies among species, as DNA synthesis peaks at mid-gestation in the intima and media in the guinea pig, whereas it occurs later in gestation in the rat [13, 31].

On the other hand, allowing pathogen persistence by dampening imm

On the other hand, allowing pathogen persistence by dampening immune activation may also be beneficial when immune-mediated collateral damage to the host outweighs injury caused by pathogen persistence. In this regard, Treg cells play important roles in counterbalancing immune effectors during persistent infection. This was first described 10 years ago for Leishmania major infection, where immune suppression

by CD25+ CD4+ Treg cells was found to promote pathogen persistence in the skin after intra-dermal infection.11 More recently, these findings have been recapitulated for other persistent infections using more refined strategies that allow Treg-cell manipulation based on Foxp3 expression. For example, the ablation of Foxp3+ cells based on selective expression of the Thy1.1 MAPK Inhibitor Library molecular weight congenic marker in mixed bone marrow chimera mice before pulmonary infection with Mycobacterium tuberculosis stimulates more robust effector CD4+ T-cell interferon-γ production and reduced pathogen burden at the site of infection.58 Similarly, Foxp3+ Treg cells provide a similar protective role in a model

of typhoid fever caused by persistent Salmonella Sirolimus order infection in Nramp1-resistant mice.59 At early time-points following infection when the activation of effector T cells is blunted and progressively increasing Salmonella bacterial burden occurs, Treg-cell ablation in Foxp3DTR mice accelerates

the activation of effector T cells with significant reductions in recoverable bacteria.59 In turn, at later time-points during persistent Salmonella infection when effector T cells are already activated and progressive reductions in pathogen burden naturally occur, the impacts of Foxp3+ cell ablation are marginalized with only modest incremental augmentation of effector T-cell activation and no significant changes in pathogen burden.59 Hence, Foxp3+ Treg cells blunt effector T-cell activation that impedes pathogen eradication, and the significance of Treg-cell-mediated immune suppression can shift and dictate the tempo of some persistent Cepharanthine infections. Although these results suggest that Treg cells play detrimental roles in host defence by preventing pathogen eradication, the reduced susceptibility against secondary infection related to low-level pathogen persistence for other pathogens (e.g. Leishmania and Plasmodium) illustrates that Treg cells may in fact provide protection against more severe disseminated infection with potentially fatal consequences.30,60,61 It will be interesting to investigate if these Treg-cell-mediated protective activities against secondary infection are more broadly applicable for other pathogens that cause persistent infection.