In this study, we analyzed the impact of IL-7/IL-7R signaling components on the generation, composition and function of circulating Treg. We hypothesized that an impairment of this learn more pathway might add to the aberrant T-cell homeostasis and Treg dysfunction associated with MS. Most resting lymphocytes express the IL-7 receptor, which is composed of the IL-7Rα-chain and the common cytokine γ-chain. Basal responsiveness of naïve subsets to IL-7 is important for their sustained survival and facilitates homeostatic cycling and differentiation of RTEs 10, 22. In consistence

with an essential role of IL-7/IL-7R signaling for the maintenance of naïve T cells, we provide evidence that the expression level of the IL-7Rα chain on Tconv is closely linked to the percentage of RTEs defined as CD31-coexpressing naïve T cells within the peripheral T-cell pool. This applies not only to conventional CD4+ T cells as described earlier 11, 12, but also to the Treg subset despite the distinctively lower overall levels of CD127 expressed on Treg, which together with intracellular FOXP3 expression and high surface expression of CD25 defines the Treg phenotype in humans 23–25. The reciprocal relation between IL-7Rα-MFIs on Tconv and plasma concentrations of

IL-7 detectable in our study underlines the tight balance between the components of this signaling pathway. Here, we show that the amount of IL-7Rα expressed on the surface of Tconv and check details Tconv subsets is significantly decreased in patients with MS. As an important finding, reduced IL-7Rα-MFIs in MS-derived Tconv strongly correlated with both reduced frequencies of RTE-Tconv and RTE-Treg and with reduced Treg-mediated inhibitory activities. Therefore, by determining the prevalences of circulating RTE-Treg, IL-7Rα expression appears to affect the suppressive capacity of total Treg, which is in line with previous studies demonstrating that proportions of RTE-Treg are critical for the function of total Treg 2, 3. A decline of IL-7Rα-MFIs was detectable

in approximately two-thirds of patients with MS, whereas 30% of patients showed HC-like levels of IL-7Rα together with normal RTE-frequencies and normal Treg functions. This observation is consistent with earlier findings of a minority of MS patients Rolziracetam exhibiting normal Treg homeostasis and suppressive properties 26. Of note, IL-7Rα expression on Tconv and RTE-Treg were decreased in HC donors of older age whereas age related effects were abolished in MS patients. This substantiates the assumption that immunosenescence might play a role in the development of this disorder 27. As a typical phenotypic feature of the Treg subset IL-7Rα expression is downregulated on circulating Treg 23–25. As expected, we found low levels of IL-7Rα on Treg and Treg subsets in all blood samples analyzed (data not shown). Thus, the MS-related reduction of IL-7Rα-MFIs on Tconv was not detectable in Treg.

Furthermore, FISH is not a stand-alone technique in the diagnostic setting, as culture is still used for antibiotic susceptibility testing. While traditionally the probes for FISH were based on single selleck products stranded DNA, another set of probes increasingly used in diagnostics are based on a polyamide ‘peptide’ backbone (Egholm et al., 1993; Bjarnsholt et al., 2008). PNA FISH probes abide by Watson/Crick

pairing but possess unique hybridization characteristics because of their uncharged chemical backbone, including rapid and stronger binding to complementary targets compared with traditional DNA probes. PNA probes can also be used with unfixed biological samples; however, only a limited number of probes are currently available, restricting the use of PNA FISH for the present. CLSM and FISH emphasize that demonstrating biofilm spatial organization is extremely important to: (1) identify whether the bacteria present are aggregated, (2) indicate a polymicrobial nature of a biofilm, (3) indicate the extent of biofilm on a surface that CFU may vastly underestimate, and (4) to show biofilm EPS that may comprise a greater

part of the biofilm than cells alone. On nonbiological, flat surfaces, biofilm spatial organization can best be measured by various parameters using image analysis software. The most common program is comstat that yields a number of spatial parameters including thickness, biovolume, BYL719 cost and roughness (Heydorn et al., 2000). Quantification of biofilm spatial organization is harder Branched chain aminotransferase however in clinical specimens that usually have a complicated and convoluted surface geometry, and currently is largely descriptive

or qualitative in these samples – that is, data showing cells or clusters per unit area without a good method to quantify spatial dimensions. As comstat thresholding does not work well on tissue backgrounds, quantifying the biofilm involves a manual rendering of biofilm images in other software to resolve bacteria and laborious cell counting, particularly if NA probes are used because they stain host cell nuclei as well as bacterial DNA (Nistico et al., 2011). Resolving biofilm spatial organization is also made more difficult because of the spatial scales involved. For example to be able to resolve individual bacteria in an image, the field of view needs to be on the order of 100 μm2, while the specimen might be on the order of cm2 (1 million fields) for tissue or even 100s of cm2 (over 100 million fields) for large orthopedic implants making microscopic data from a small proportion of the sample often the only practical method to demonstrate biofilm in situ. Finally, because biofilms may also be extremely localized, it is difficult to quantify by averaging several images on the surface, because heterogeneity leads to extensive sample variability.

1E), suggesting a dysregulated expansion of donor TEFF cells in the absence of TREG cells. In order to examine kinetics of lymphocyte proliferation in TCR-β−/− recipient mice, cycling cells from secondary lymphoid tissues and LP were determined by intracellular Ki-67 expression at different time points during disease progression. Our results show a progressive

increase in frequencies and selleck compound absolute numbers of cycling lymphocytes in colitic mice (Fig. 1F), which was significantly decreased in all lymphoid organs examined, as well as in the LP, upon TREG-cell co-transfer (Fig. 1F and G). More importantly, the reduced absolute numbers of donor TEFF cells in mesLN compared with LP (Fig. 1G) suggests that TREG cells hamper the expansion and accumulation of pathogenic cells in the site of AZD6244 mouse tissue inflammation. Studies show that a prominent role for Th1, and in particular Th17, polarized immune responses in autoimmunity and IBD-like disorders in humans and in mouse models 44, 45. In particular,

IL-17-secreting T cells are found in lesions of patients with CD 4, 22, 25, and genome-wide association studies of CD and ulcerative colitis patients indicate the importance of Th17-promoting factors, including IL-23, in IBD 46, 47. We then sought to characterize the inflammatory nature of the mucosal inflammation. We observed a significant increase in IFN-γ IL-1β, IL-12 and IL-6 mRNA expression in colons of mice reconstituted with

CD4+CD25− TEFF cells alone, while CD4+CD25+ TREG cell-mediated protection from colitis correlated with higher levels of IL-4 and IL-10 mRNA expression (Fig. 2A). Moreover, we found a marked increase in frequencies and absolute numbers of IFN-γ- and IL-17-producing lymphocytes in secondary lymphoid tissues and LP of colitic mice (Fig. 2B–E), indicating that TREG cells potently Thiamet G suppress the priming and expansion of these cells in protected mice. Interestingly, our results reveal a temporal difference in the emergence of IFN-γ- and IL-17-producing cells. While IFN-γ was highly expressed in the absence of TREG cells in both perLN and mesLN (Fig. 2B), IL-17 secretion was more specific to the intestinal tissue (Fig. 2B and C). This is consistent with previous studies pointing to the mucosa as a privileged site for Th17-cell development due to elevated secretion of specific polarizing mediators such as IL-6 and TGF-β1 25. Moreover, while the frequency of IFN-γ-secreting CD4+ TEFF cells (≈40% of CD4+ T cells) in the inflammatory site remained unchanged during colitis development, the frequency of IL-17+ donor CD4+ TEFF cells steadily dropped from 35% at day 7 to 20% at day 21 (Fig. 2D and E), suggesting a role for different signals in the initial and progressive phases of T-cell-induced colitis in TCR-β−/− mice.

Also, significantly more ITP patients harboured ORF SNPs (34·5%) compared to healthy controls (18·0%; P = 0·009). Further investigations demonstrated that FCGR2C harbouring an ORF encodes a surface expressed FcγRIIc on natural killer (NK) cells (Fig. 5). Furthermore, NK cells

with FcγRIIc can mediate antibody-dependent cellular cytotoxicity (ADCC) to antibody-coated targets, demonstrating that FcγRIIc acts as an activating IgG receptor. IVIG-induced anaphylaxis in a patient with CVID has been shown to be probably related to variation in FCGR genes (Kuijpers, unpublished data). A Caucasian female was diagnosed with CVID. She had recurrent infections and chronic Giardia lamblia-related diarrhoea. After the start of IVIG, the patient complained of abdominal pain, a generalized rash, tachypnoea and tachycardia with a fall in blood pressure, followed by chills and fever. IVIG see more infusion was stopped and anti-histamines (clemastin, 2 mg), Metformin steroids (DAF, 25 mg) and NaCl 0·9% (500 ml) were administered intravenously. Blood cultures remained sterile, concentrations of serum tryptase and complement activation products

were not increased; however, elevated elastase was detected. IgG–anti-IgA complexes are not always clinically relevant and are no longer tested for routinely prior to infusion. In this case, due to the anaphylaxis, preinfusion serum samples were analysed and showed the presence of anti-IgA antibodies of the IgG1 subclass. Investigation of FCGR2 revealed a novel splice variant in exon 6 of FcγRIIa that is characterized by normal mRNA and protein expression, and represents a potential gain-of-function variant through elongation of the cytoplasmic tail. The expression of this splice variant has been found in eight individuals, including one patient with CVID, three with vasculitis of whom one developed insulin-dependent diabetes type 1 and in one healthy control. FcγRIIa-mediated hyper-reactivity may be proposed as a mechanism to explain severe anaphylactic reaction to IVIG. More CVID patient serum samples are required to fully characterize the clinical response. Thus, FCGR2C represents a gene with variable expression that is highly relevant for immunity, probably contributing

to susceptibility and severity of infections and autoimmune disease. A balance between inhibitory (FcγRIIb) and activating FcγRs (FcγRIIa, FcγRIIcorf, FcγRIIIa, FcγRIIIb) is important for immune Florfenicol reactivity. High-dose IVIG treatment is thought to exert an immunomodulatory effect by numerous mechanisms, including engagement of the inhibitory FcγRIIb receptor and/or by saturation of the neonatal Fc receptor, FcRn. FcRn is a human leucocyte antigen (HLA) class I-related receptor that transports IgG antibodies within and across a diverse array of different cell types. Through this transport, FcRn serves multiple roles throughout adult life that extend well beyond its previously defined function of transcytosing IgG molecules from mother to offspring.

The increased T cell activation

and CD146 expression in our sSS patients was not explained by unique features with regard to disease activity, serology or severity of immunosuppression, compared to the other patient groups (Supporting information, Table S1). T cell hyperactivity Navitoclax mouse may be inherently greater in sSS, or more difficult to control with drugs, relating possibly to more extensive organ involvement than would be present in pSS, for example. However, other clinical variables, rather than their diagnosis of sSS, might have been critical. In any case, combinatorial analysis of T cell activation markers and CD146 could aid differentiation between patient subgroups on a clinical spectrum of CTD. Future studies will show whether this might identify subpopulations of CTD patients who would benefit from more aggressive therapy, or from targeting Th17 cells specifically. Effector lymphocyte subsets are recruited to inflammatory sites by several mechanisms. T cell recruitment by CCL21 and its receptor, CCR7, promotes ectopic lymphoneogenesis at inflammatory lesions in subsets of patients with Sjögren’s syndrome and SLE [38-40]. Another pathway recruits effector T cells via other, proinflammatory chemokines and their receptors,

including CCR5 [41]. The Cell Cycle inhibitor correlation between CD146 and CCR5 on T cells suggests that CD146 participates in the latter pathway, and this may be exaggerated in our sSS patients. This is consistent with increased CD146 expression by tissue-infiltrating T cells (see Introduction). One study reported that the frequency of circulating CD146+ apoptotic cells was elevated in SLE, correlating with endothelial dysfunction, a known risk factor for atherogenesis and cardiovascular morbidity [42]. Endothelial

cells were enumerated by staining for CD146, but lymphocytes were not excluded. However, circulating endothelial cells (defined by CD146 and other endothelial Cyclin-dependent kinase 3 antigens and absence of leukocyte markers [43]) are vastly outnumbered by CD146+ lymphocytes, which might have confounded these results [7] (Supporting information, Fig. S10). The possibility remained that CD146 might identify a pro-atherogenic T cell subset. However, we observed no increase in the frequency of CD146+ T cells in SLE, even though atherosclerosis is accelerated in this disease [12, 44, 45]; nor did we find unusual patterns of CD146 expression on T cells in HDs with a history of CVD. T cells in atherosclerotic plaque are CD4+CD28–, and an increased frequency of such cells in blood correlates with atherosclerosis [18, 46], yet we found no correlation of CD28 down-regulation with CD146 expression. T cells in atherosclerotic plaque express CCR5 [47-50], and this marker was associated weakly with CD146 expression; however, CCR5 also directs homing to other inflamed tissues and to the gastrointestinal tract.

Ralph Steinmann was awarded one half of the Nobel Prize “for his discovery of the DC and its role in adaptive immunity,” since he unraveled their professional antigen-presenting function that shapes adaptive immune reactivity and tolerance. Jules Hoffmann and Bruce Beutler shared the other half

of this Nobel Prize for their discoveries MK2206 on how Toll (in flies) and TLRs (in mammals) activate innate immunity. Here, I have discussed my view of innate immunity’s path to the Nobel Prize, and pointed out the evolving paradigm shifts in how we have viewed immunity over the past century. Obviously, the Nobel Prize decision highlighted the biological importance of the initial discoveries, but these discoveries now impact tremendously on our understanding of age-related autoinflammatory diseases, intestinal function, and the putative interdependence of the gut’s microbiota and adaptive immunity. We all look forward to this century’s discoveries. The author declares no financial or commercial conflict of interest. “
“Citation Winger EE, Reed JL. Low circulating CD4+ CD25+ Foxp3+ T regulatory cell levels predict Small molecule library supplier miscarriage risk in newly pregnant women with a history of failure. Am J Reprod

Immunol 2011; 66: 320–328 Problem  The purpose of this study was to determine whether quantification of peripheral blood Treg cell levels could be used as an indicator of miscarriage risk in newly pregnant women with a history of immunologic reproductive failure. Method of Study  Fifty-four pregnant women with Isotretinoin a history of immunologic infertility and/or pregnancy loss were retrospectively evaluated (mean age: 36.7 ± 4.9 years, 2.8 ± 2.5 previous miscarriages; 1.5 ± 1.9 previous IVF failures). Twenty-three of these women experienced another first trimester miscarriage, and 31 of these women continued their current

pregnancies past 12 weeks (‘pregnancy success’). The following immunologic parameters were assessed in the first trimester: NK cell 50:1 cytotoxicity, CD56+ 16+ CD3− (NK), CD56+ CD3+ (NKT), TNFα/IL-10, IFNγ/IL-10, CD4+ CD25−Foxp3+, total CD4+ Foxp3+ (CD4+ CD25+ Foxp3 plus CD25− Foxp3+), and CD4+ CD25+ Foxp3+ levels. Results  Patients with successful ongoing pregnancies experienced a mean (CD4+ CD25+ Foxp3+) ‘Treg’ level of 0.72 ± 0.52%, while those that miscarried in the first trimester experienced a mean Treg level of 0.37 ± 0.29% (P = 0.005). Markers not significantly different between the loss and success groups were NK 50:1 cytotoxicity (P = 0.63), CD56+ 16+ 3+ NK cells (P = 0.63), CD56+ 3+  NKT (P = 0.30), TNFα+IL-10+(P = 0.13), IFNg+IL-10+ (P = 0.63), and CD4+ 25− Foxp3+ cells (P = 0.10), although total CD4+ Foxp3+ levels remained significant (P = 0.02) and CD4+ 25+ Foxp3+ showed the most significant difference (P = 0.005). Mean day of blood draw was 49.2 ± 36.1 days pregnant (median 39.0 days). In addition, patients with a low Treg level (<0.

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 Selleckchem H 89 vivo allergic reactions. First, we examined amplifying effects of adenosine on release of β-hexosaminidase, one of the intragranullar enzymes, from BM-derived AZD2014 ic50 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 CYTH4 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.

[94-96] The repertoire of CD1d-presented self-antigen is responsive to an APC activation state. Staining with tetramerized iNKT TCR, and comparison of the repertoire of CD1d-associated

self-GSL in resting and LPS (TLR4)-stimulated myeloid DC, shows that TLR stimulation of DC causes an increase in presentation of iNKT-activating CD1d ligands.[30, 37] Triggering of TLR4 and TLR7 or TLR9 on DC activates iNKT cells, and this activation requires APC synthesis of charged β-linked GSL.[29] In inflammation, www.selleckchem.com/products/r428.html APC levels of lysophosphatidylcholine increase, though lysophosphatidylcholine is only a weak activator of iNKT cells.[41] A more important role is indicated for β-GlcCer. It is synthesized in response to TLR agonists, and inhibition of this synthesis impairs iNKT responses to DC cultured with bacteria. Further, bacterial infection of mice leads to accumulation of β-GlcCer at sites of E. coli or Streptococcus pneumoniae infection.[11]

In mice, TLR stimulation PD0325901 chemical structure of DC inhibits α-galactosidase A, which normally degrades lysosomal self-antigens to prevent full iNKT activation, though this mechanism is unlikely to be important in humans.[97, 98] CD1d and DC-dependent but TLR-independent activation of iNKT cells has been reported in responses to fungi including Aspergillus and Candida.[99] Fungal cell wall β-1,3-glucans bind pattern recognition receptors on APC to stimulate IL-12 release, which activates RVX-208 autoreactive iNKT cells. Invariant NKT cells also form part of the response to helminths, though the mechanism remains partly delineated. There is a requirement for CD1d, and for schistosome egg recognition by DC, though neither IL-12 nor TLR signalling is necessary.[100] Activation of iNKT cells in mouse cytomegalovirus infection is antigen-independent, relying on APC-derived IL-12.[101-103] In this context, iNKT cells behave as innate lymphocytes, amplifying the

immune response, a capacity that widens the range of pathogen defences in which they could be involved. The APC-derived cytokines have also been demonstrated to drive antigen-independent iNKT activation in a model of E. coli infection.[104] Priming of iNKT cells to be more responsive to IL-12 in the absence of foreign antigen 85 suggests that there is a hierarchy of activation stimuli for iNKT cells. For example, in response to Salmonella typhimurium, IL-12 amplifies a weak response to self-antigen,[24, 5] and DC from patients with advanced cancer are better able to activate iNKT cells if supplemented with IL-12.[105] If exogenous antigen, self-antigen and IL-12 are all present, which is the most important in activating iNKT cells? Many studies exploring iNKT-cell activation use hybridoma cell lines, which may lack the ability to respond to both antigen and cytokine signals. To address this, Brigl et al.

In our study, we have shown that the numbers of myeloid and plasmacytoid DCs in patients with SLE are the same as in previous reports. Furthermore, the same decrease of myeloid

and plasmacytoid DCs were observed in patients with SLE-merged secondary SS. Meanwhile, there were no significant differences in the number of myeloid and plasmacytoid DCs among SSc-merged secondary SS patients and RA-merged secondary SS patients, as well as SSc and RA patients. However, we found a direct correlation between the number of myeloid DCs and the time from the onset of Sicca syndrome in patients of secondary SS. A similar correlation was also observed in patients with primary SS. We also found a negative correlation between the number of blood myeloid DCs and the frequency of tissue-infiltrated DCs in both primary and secondary SS. Furthermore, in contrast to the early phase of primary SS, in the Antiinfection Compound Library cell line minor salivary glands of primary later-phase SS patients the mature DCs disappeared. These findings suggest that the reduction of myeloid DCs is a common finding in the early stage of https://www.selleckchem.com/products/ulixertinib-bvd-523-vrt752271.html Sicca syndrome and that myeloid DCs contribute to the critical and pathogenic roles of Sicca syndrome of SS. In this study we hypothesized

that preferential trafficking of myeloid DCs into salivary or lachrymal glands play essential roles in the pathogenesis of Sicca syndrome of primary and secondary SS by initiating Th1 immune responses. It has been reported that in patients in the later phase of SS, the percentage of infiltrating B cells within the salivary glands is increasing [24–26], suggesting that cell interaction between DCs and helper T cells is no longer required. Further detailed studies will be required to determine which antigens trigger DC-mediated immune responses in the salivary glands of SS patients. Our data

raise the possibility that the infiltration of myeloid DCs within salivary glands has been caused by the early onset of SS; meanwhile, retaining inflammation may require another mechanism in the later phase of SS. This work was supported by a Grant-in-Aid for Scientific Carbohydrate Research (C) (subject 11670466) from the Japan Society for the Promotion of Science. None of the authors have any conflict of interest with the subject matter or materials discussed in the manuscript. “
“Glucocorticoid (GC) is often given when preterm delivery is expected. This treatment is successful in stimulating the development of the fetal lung. However, reports and related research regarding the prolonged effects of prenatal GC on the development of immunity are very limited. Some data, derived from infants whose mothers were given immunosuppressants during pregnancy for the treatment of autoimmune disorders, suggest that prenatal exposure to GC may have only a limited effect on the development of the immune system. What is unknown is whether the immune modulation effects of prenatal GC might appear at a later childhood stage and beyond.

monocytogenes (Longhi et al., 2008). Biofilm formation by S. epidermidis and S. aureus requires surface protein (Aap and SasG) that contain sequence repeats known as G5 domain (Rohde et al., 2005; Corrigan et al., 2007; Geoghegan et al.,

2010). Dimerization of the G5 domains in the presence of Zn2+ is essential for these proteins to function as intercellular adhesin (Conrady et al., 2008). Zn2+ chelation Kinase Inhibitor Library research buy was shown to specifically prevent biofilm formation by S. epidermidis and methicillin-resistant S. aureus, which was proposed as a potential approach for combating biofilm-related infections (Conrady et al., 2008). Antiparasitic drug nitazoxanide and its active metabolite, tizoxanide, were reported to inhibit S. epidermidis biofilm formation possibly by targeting the zinc-dependent adhesin Aap (Tchouaffi-Nana et al., 2010). Polysaccharide intercellular adhesin (PIA) synthesized by the icaADBC operon of Staphylococci is one of the best understood EPS components and is essential for Staphylococci biofilm Atezolizumab supplier development. Thus the ica genes represent potential targets for biofilm inhibitors.

Oduwole et al. (2010) reported that the antibacterial agent povidone-iodine at sub-inhibitory concentrations has anti-biofilm activity against S. epidermidis by activating the icaR transcriptional repressor in S. epidermidis and reducing the transcription of the icaADBC operon (Oduwole et al., 2010). More recently, the organosulfur compound from garlic, allicin, was shown to inhibit PIA biosynthesis and biofilm development by S. epidermidis (Cruz-Villalon & Perez-Giraldo, 2011). Sulfhydryl compounds such as dithiothreitol, beta-mercaptoethanol or cysteine were also shown to reduce S. aureus biofilm formation

by inhibiting PIA biosynthesis 3-mercaptopyruvate sulfurtransferase probably through metabolic interventions (Wu et al., 2011a, b). Biofilm formation involves many ‘social’ activities including those of quorum sensing, iron siderophore and biosurfactant production (Davies et al., 1998; Davey et al., 2003; Banin et al., 2005; Alhede et al., 2009). Interference of these group activities can affect biofilm architecture and antibiotic resistance. Quorum sensing is widely used by microorganisms to coordinate communal behaviours such as bioluminescence, swarming and production of virulence (Rasmussen et al., 2000; DeLisa et al., 2001; Miller et al., 2002). Quorum sensing regulation is achieved by synthesizing and releasing small signal molecules by many denoted autoinducers (AIs), a word inspired from their positive feedback effect on expression of bioluminescense. The structures of AIs and their receptors have been extensively characterized (Shaw et al., 1997; Vannini et al., 2002; Bottomley et al., 2007).