In contrast to naturally occurring CD4+CD25+ Tregs, DN T cells ha

In contrast to naturally occurring CD4+CD25+ Tregs, DN T cells have to be activated by antigen-presenting cells (APCs) to induce their regulatory

potential. The suppressive activity of DN T cells is neither mediated indirectly by modulation of APCs nor by competition for T-cell growth factors. Furthermore, DN T-cell-mediated suppression toward responder T cells is TCR dependent and requires novel protein synthesis. In contrast to murine MAPK Inhibitor Library research buy DN T cells, which eliminate effector T cells via Fas/FasL or perforin/granzyme, human DN T cells suppress proliferation of responder T cells by cell contact-dependent mechanisms. Taken together, our data indicate that human DN T cells exert strong immunosuppressive effects on both CD4+ and CD8+ T cells and may serve as a new therapeutic approach to treat autoimmunity and transplant rejection. Suppression of immune responses by Tregs is critical

for the induction and maintenance of self-tolerance. Tregs have been shown to be involved in downregulating immune responses Everolimus in autoimmunity, transplant rejection, graft-versus-host disease (GvHD), and tumor immunity 1–3. Numerous studies demonstrated that a variety of T-cell subsets possess immunoregulatory properties: the population of thymus-derived naturally occurring CD4+CD25+ forkhead box P3 (Foxp3)+ T cells is currently the most extensively investigated subset of Tregs and their role has been studied in a wide range Carnitine dehydrogenase of animal models and in humans 4–7. However, inducible Tregs such as T-regulatory type 1 (Tr1) cells,

T-helper 3 (Th3) cells, CD8+CD28− T cells, and TCR-αβ+ CD4−CD8− double-negative (DN) T cells are generated in the periphery and also show the ability to inhibit immune responses 8–11. In both mice and humans, about 1–5% of all peripheral T cells are of TCR-αβ+ DN phenotype 11, 12. These cells express a specific set of cell surface molecules and show a characteristic cytokine profile 11, 13. The group of L. Zhang was the first to identify and characterize the immunoregulatory function of DN T cells. They have demonstrated that murine DN T cells specifically eliminate activated anti-donor CD4+, CD8+ T cells and B cells 11, 13–15. Moreover, adoptive transfer of DN T cells prolongs skin and heart allograft survival in murine models 11, 13, 16–19. Others have shown that mouse DN T cells are highly potent in suppressing T-cell responses both in vitro and in vivo in an antigen-specific manner and therefore induce skin and islet allograft survival 20. Even now, the function and ontogeny of human DN T cells still remains elusive. Of interest, in a recent clinical report, an inverse linear relationship between the severity of GvHD and the frequency of DN T cells could be demonstrated in patients after allogeneic stem cell transplantation 21.

, 2003) Addition of DSF can activate an

extracellular en

, 2003). Addition of DSF can activate an

extracellular enzyme, single endo-beta-1,4-mannanase, which disrupts the extracellular polysaccharide xanthan and triggers the dispersion of the Xcc biofilms (Dow et al., 2003). A DSF structurally related short-chain fatty acid signalling molecule, cis-2-decenoic acid, was identified from P. aeruginosa cultures and found to induce the dispersion of established biofilms formed by many bacterial species, such as P. aeruginosa, E. coli, K. pneumoniae, P. mirabilis, Streptococcus pyogenes, Bacillus subtilis, S. aureus, and C. albicans (Davies & Marques, 2009). Barraud et al. (2006) reported that the anaerobic respiration processes are involved in P. aeruginosa biofilm dispersion, and nitric oxide (NO) can cause dispersion of P. aeruginosa ITF2357 price biofilms (Barraud et al., 2006). They further showed that the NO donor sodium nitroprusside efficiently disperses P. aeruginosa biofilms and greatly Anti-infection Compound Library cell assay enhances the activity of conventional antimicrobial compounds against P. aeruginosa biofilms. Ginseng extract was recently shown to disperse P. aeruginosa biofilms by facilitating twitching and swimming motility, which further enhance the activity of conventional antimicrobial compounds against P. aeruginosa biofilms (Wu et al., 2011a). 2-aminoimidazole-derived anti-biofilm agents are extensively studied and are shown to enhance the activity of conventional antibiotics against biofilms

Carnitine palmitoyltransferase II (Richards & Melander, 2008; Richards et al., 2008; Rogers et al., 2010; Rogers et al., 2011). Agents targeting the EPS components are frequently

reported to induce biofilm dispersion. Bacillus licheniformis secretes an extracellular DNase (NucB) that rapidly disperses the biofilms formed by both Gram-positive and Gram-negative bacteria (Nijland et al., 2010). D-amino acids treatment was shown to cause the release of amyloid fibers that link cells in biofilms at nanomolar concentrations and disperse biofilms formed by S. aureus and P. aeruginosa (Kolodkin-Gal et al., 2010). Johansson et al. (2008) screened combinatorial libraries of multivalent fucosyl-peptide dendrimers and identified high-affinity ligands of the fucose-specific lectin (LecB) of P. aeruginosa (Johansson et al., 2008). They showed these dendrimers can completely disperse biofilms formed by the wild-type strain and several clinical P. aeruginosa isolates. There is an urgent need to develop novel strategies to control biofilms in industrial and clinical settings. A wide range of promising approaches have been evaluated in different biofilm model systems. However, dealing with natural biofilms formed by multi-species is more complicated than the biofilms formed by single-species in our model systems since the mechanisms of multi-species biofilm formation is not well investigated. More reliable techniques for investigating biofilms and better model systems for evaluating control strategies are still required.

Interestingly, upon 45 min

Interestingly, upon 45 min Stem Cells antagonist coincubation of the T-cell with their APC the major axis of the synapse was 12 μm in the depicted control siRNA-treated T cell, whereas only 6.8 μm were observed in the LPL knock-down T-cell (Fig. 6A). To evaluate the whole population of T-cell/APC couples, we set a cutoff for an enlarged contact zone. Thus, a contact zone was counted as increased if the major axis exceeded 9.5 μm, i.e. a 5% increment over the average T-cell diameter of 9 μm. Such

an enlarged contact zone was found in 62% of T-cell/APC couples with control siRNA-treated T cells. A significantly reduced number of LPL knock-down T cells (37%) displayed such an enlarged contact zone (Fig. 6A and B). This reduced size of the contact zone is not due to a reduced size of the LPL knock-down T cells, since the mean diameters of LPL knock-down and control siRNA-treated T cells were equal (Fig. 6A and C). Kinetic evaluations showed

that the observed difference in the size of the contact zone was only apparent after longer time points. If short-term interactions were evaluated (<30 min), there was hardly any difference in LPL knock-down or control T cells (Fig. 6D). This reflects the kinetics of the reduced LFA-1 enrichment in LPL knock-down T cells (Fig. 5G). To analyze whether only LFA-1 macrocluster formation was reduced in LPL knock-down T cells or if they had a general diminished cluster formation within the IS, we evaluated the size of the CD3 macroclusters. In control T cells, the size of the CD3-macroclusters PD98059 chemical structure got smaller over time, which was in line with the fact that Cetuximab in vitro CD3 coalesce and modulate in the cSMAC. LPL knock-down T cells already started with a slightly smaller CD3 macrocluster, but ended up with the same size of CD3 macrocluster as control T cells upon 45 min

(Fig. 6E). Since LPL knock-down T cells ended up with a contact zone of a smaller size, the CD3 macroclusters by trend covered a bigger proportion of the contact zone in LPL knock-down T cells (Fig. 6F). Taken together, the reduced size of the contact zone seemed to be the result of a reduced LFA-1 accumulation, which may impar T-cell spreading on their APC. In line with that assumption, the area of CCL21-stimulated T cells on immobilized ICAM-1 was also reduced in LPL knock-down T cells (Supporting Information Fig. 6) 29. Due to the profound effects of an LPL knock-down on the T-cell/APC contact zone we analyzed whether calcium influx and adhesion on APC was also disturbed. Thus, TLV was performed for 240 min with fluo-4-labeled LPL knock-down or control T cells and superantigen-loaded APC (Fig. 7A and Supporting Information Movies 1 and 2). These experiments showed that both LPL knock-down and control T cells were able to induce a calcium influx. However, the calcium signal was more persistent in control T cells as compared to the LPL knock-down T cells.

2B bottom and data not shown), i e have the same phenotype of B-

2B bottom and data not shown), i.e. have the same phenotype of B-1 cells in the spleen (Supporting Information Fig. 1). Importantly, these spontaneous natural IgM-secreting cells are thus distinct from a recently described BM IgMloIgDhi B cell subset that is induced following T-independent responses to blood-borne pathogens to secrete IgM 42. Our phenotype-based functional analysis strongly suggested the presence of spontaneous IgM secreting B-1 cells in the BM. To confirm this, we generated Ig-allotype chimeric mice that harbor B-1 and B-2 cells of different allotypes, Igh-a and Igh-b respectively

25, 26, 43, 44. Using Ig-allotype BIBW2992 mouse and isotype-specific monoclonal antibodies, even low frequencies of B-1 (Igh-a) cells can be identified in these chimeras without having to rely on surface markers that might change upon activation

and/or differentiation of B-1 cells. Flow cytometric analysis of these mice demonstrated the presence of B-1 cells in PerC, spleen and the BM (Fig. 3A). BM B-1 cells (Igh-a) were CD19hiCD43+, i.e. identical to the population of spontaneous IgM-secreting cells in BALB/c mouse BM (Fig. 3A and Fig. 2B). Comparative analysis of B-1 cells in PerC, spleen and BM showed similar phenotypic profiles of splenic and BM B-1 cells and consistent differences of these two populations compared with PerC B-1 cells. Spleen and BM B-1 cells were larger compared with resting B-2 cells but smaller than B-1 cells in the PerC. CD43 was expressed homogeneously on B-1 cells in BM Plasmin and spleen (Fig. 3B) and CD11b was not expressed by

these cells (25 and data not shown). In contrast, PerC B-1 cells showed a bimodal expression pattern of CD43 and most expressed CD11b (Fig. 3B and data not shown). B-2 cells lacked both markers completely, at least in steady state (25, 30, 45 and Fig. 3B). Independent of their tissue location, all B-1 cells expressed higher levels of CD19 than B-2 cells and B-1 cells in all tissues were heterogeneous with regard to surface expression of CD5 (Fig. 3B), with the majority (> 80%) expressing measurable levels of CD5. B-1 (Igh-a) cell frequencies in the BM were about 6-fold lower compared with those found in the spleen (0.44±0.13% and 2.33±0.58% among live cells respectively) and >100-fold lower than in the peritoneal cavity (Fig. 3C). We identified similar frequencies of IgM+CD43+CD5+/− B cells in the BM of BALB/c mice (Supporting Information Fig.1). Given the total number of BM cells received per femur (mean of 4.59×107/cells per BALB/c mouse; n=8) and a calculated number of total BM cells (one femur =12.7% of total BM cells 46, i.e. 3.61×108/mouse), we can calculate the total number of BM B-1 cells to be roughly 1.6×106/mouse. A very similar number is found in the spleen: 1.8×106 (mean of 7.74×107 total cells/mouse; n = 9; and 2.33% B-1 cells) and half of the number found in the peritoneal cavity: 3.

cruzi, an event that is not uncommon [1, 3] (Fig  4A) Antibody t

cruzi, an event that is not uncommon [1, 3] (Fig. 4A). Antibody titre to the three OSI906 Trk receptors decreased sharply six months afterwards, when the patient was shifting to the chronic phase, and became undetectable 15-16 years after the start of the accidental infection (Fig. 4A), while the patient remains asymptomatic. The patient continues to be infected with T. cruzi and thus with Chagas’ infection because of the high antibody titres to the parasite >15 years after the onset of infection

(Fig. 4B). This illustrates that a Trk-Ab-seropositive patient in the acute phase can be converted to Trk-Ab-seronegative, consistent with 100% patients bearing acute Chagas’ disease Trk autoantibodies and with some patients (∼20%)

converting to Trk-Ab-seronegative when progressing to the chronic phase of the disease. In sum, our results show that individuals acutely infected with T. cruzi produce autoantibodies specific to TrkA, TrkB and TrkC, the tyrosine kinase receptors of the neurotrophins NGF, BDNF and NT-3 that regulate development and repair selleck compound of central and peripheral nervous system [9, 16]. They were elicited by patients as young as a 4-year-old child and as aged as a 66 year-old adult and, thus, by an age-independent process. Given that acute infection starts after the parasite gains access to humans and lasts only a few months, the Trk autoantibodies should arise relatively soon after T. cruzi infection.

This was dramatically demonstrated in a patient with Chagas’ disease accidentally infected in a laboratory, as high titres of antibodies were evident less than two months after the accident (Fig. 4A). The Trk autoantibodies from patients with acute Chagas’ disease bear characteristics of antibodies produced in acute disease or after primary immunization (IgM and IgA isotype and low avidity). Unravelling the immunochemistry and biology of these neurotrophin receptor Interleukin-3 receptor autoantibodies is of great interest because one of the autoantigens – TrkA – serves as a vehicle for T. cruzi, via its trans-sialidase/neurotrophic factor, to promote neuron survival [11] and to invade cells [10], while another autoantigen – TrkC – is used to induce survival and differentiation of neurons and Schwann cells [12]. ATA isolated from sera of patients in the indeterminate phase of Chagas’ disease compete with T. cruzi for Trk binding and inhibit infection in vitro and in vivo [13]. Consequently, ATA could modulate Chagas’ disease progression by reducing tissue parasitism in chronically infected individuals. In view of the present findings, ATA could play a role in the dramatic decline in tissue parasitism when patients progress from acute to chronic disease. This work was supported by NIH Grants NS40574 and NS42960.

In another knockout approach, selective attenuation of the CS-E m

In another knockout approach, selective attenuation of the CS-E motif via siRNA targeting significantly reduces CSPG-mediated inhibition of

neurones in vitro [210]. Accordingly, neutralizing CS-E inhibition with a function blocking antibody led to increased regeneration following optic nerve crush [189]. Based on observations of collagenous scar deposition, early enzymatic attempts at matrix modification included hyaluronidase, trypsin and elastase application to the transected spinal cord which, although initially reported to promote recovery [211], lacked benefit in further studies selleck chemicals and also caused vascular haemorrhage as a result of blood vessel basement membrane degradation [212–214]. The ECM has Buparlisib purchase endogenous remodelling enzymes. Matrix metalloproteinases (MMPs) are a family of 24 (MMP 1-28) zinc- and calcium-dependent endopeptidases. They are divided into collagenases (MMP-1, -8, -13, -18), gelatinases (MMP-2 and -9), stromelysins (MMP-3, -10, -11), and membrane-type MMPs (MMP-14, -15, -16, -17, -24, -25) and other

MMPs. Generally they have three domains, an N-terminal propeptide domain, an internal catalytic (metalloproteinase) domain and a C-terminal haemopexin (haem binding) domain [215]. Collectively they can cleave all protein components of the ECM as well as other substrates including growth factors, cell adhesion molecules and receptors [216]. Their activity is highly regulated by steps within synthesis, post-translational modifications, release as inactive zymogens and inhibition by endogenous tissue inhibitors of metalloproteinases (TIMPs). The profile of almost all of the MMPs has been investigated after spinal cord injury (reviewed extensively in [217]) at an mRNA and protein level. Acutely, blockade of MMP-mediated BBB breakdown and leucocyte extravasation is thought to be of potential therapeutic benefit [218–220] and subsequent neuroimmunomodulatory effects of MMP-9 caudal to the lesion have been implicated [221]. MMP-9 knockout mice also have reduced motor

deficits following traumatic brain injury [222]. Baricitinib In their traditional role as modulators of the ECM, some MMPs limit the formation of an inhibitory glial scar and degrade proteoglycans. For example, MMP-2 is known to degrade neurocan and versican and MMP-3 additionally degrades Tn-C, brevican, NG2 and phosphacan [223,224]. Accordingly, MMP-2 knockout mice have increased CSPG immunoreactivity, fewer serotonergic fibres caudal to the injury site, and significantly reduced motor recovery compared with wild-type mice following spinal contusion [225]. Fibroblasts genetically modified to secrete MMP-3 and transplanted following rat spinal contusion resulted in improved locomotor recovery compared with control fibroblasts, but not compared with other control groups [226].

One startling statistic computed by Haith (1980) is that the aver

One startling statistic computed by Haith (1980) is that the average 2-month-old infant has sampled its visual environment with over 250,000 fixations (looking

times between saccades) since birth. Despite the logical advantage of the foregoing constraints—which surely must assist in dealing with Problem 2—it is nevertheless the case that laboratory demonstrations of statistical learning are highly simplified compared to what an infant is actually confronted with in the natural environment. Thus, we should be concerned that such demonstrations are little more than proof of concept that under ideal conditions a statistical-learning Raf inhibition mechanism can solve certain tasks. But does this mechanism “scale up” to more natural and complex learning tasks? There are two answers to this question, at least

for studies of statistical selleck learning in the language domain. First, a variety of corpus analyses (Frank, Goldwater, Griffiths, & Tenenbaum, 2010; Swingley, 2005) have shown that, to a first approximation, the same types of statistical information manipulated in the laboratory are present in real language input to infants. Yet in real corpora, these statistical cues are less reliable, and thus, one worries that no one cue alone is sufficient. It is important to note, for historical purposes, that initial claims about statistical learning made precisely this point: “Although experience with speech in the real world is unlikely to be as concentrated Florfenicol as it was in these studies, infants in more natural settings presumably benefit from other types of cues correlated with statistical information (p. 1928)” (Saffran et al.,

1996). Laboratory studies that eliminate all potentially useful cues except one serve the purpose of showing that the sole cue present in the input is sufficient for learning. But such studies cannot confirm that in the natural environment, where many cues are correlated, any given cue plays a necessary role in learning. The second answer to the “scale up” question is to conduct laboratory experiments in which two or more cues are presented in combination to see which one “wins” or how each cue is “weighted” in the statistical-learning process. Early work that followed this strategy suggested that statistical cues “trump” prosodic cues (Thiessen & Saffran, 2003), at least at the level of lexical prosody (i.e., whether 2-syllable words have a strong-weak or a weak-strong stress pattern). The reason that lexical prosody might take a back seat to statistics is that prosody is language-specific, whereas syllable statistics, at least in most languages, are not. Yet there are other levels of prosody that are language-general and so could reasonably serve as universal constraints on which statistics are computed.

, 2004; Mattson, Riley, Gramling, Delis, & Jones, 1998; Russell,

, 2004; Mattson, Riley, Gramling, Delis, & Jones, 1998; Russell, Czarnecki, Cowan, McPherson, & Mudar, 1991). The differences in the findings relating to the spontaneous and elicited play measures illustrate the difficulty in determining which alcohol-exposed infants are adversely affected. Given that the effect of prenatal alcohol on spontaneous play was not significant after adjustment for the HOME and SES, the data suggest that infant play observed casually by a clinician will not be relevant for assessing

fetal alcohol-related impairment, whereas a direct assessment BMN 673 cell line of the infant’s capacity to imitate symbolic play behavior modeled by the examiner might well be highly informative. Identification of neurobehavioral biomarkers is particularly important in infancy when the facial dysmorphology is difficult to distinguish to facilitate determination of affected infants most in need of early intervention. A limitation of human fetal alcohol exposure studies is they that are by necessity correlational, and all possible confounding variables can not be controlled. However, replication of previous findings relating prenatal alcohol exposure to symbolic play in infants in two Erismodegib independent, cross-culturally distinct populations suggest that

this is a robust finding. The alcohol information in this study relies on self-report from the mothers. The self-reports based on timeline follow-back interviews enabled us to examine

continuous measures of alcohol exposure, which were prospectively obtained during pregnancy by trained interviewers, an approach that we have previously Monoiodotyrosine shown to be more valid than retrospective self-report in predicting neurobehavioral outcomes (Jacobson et al., 2002). The validity of the self-report was further confirmed by findings showing significant correlations between maternal self-report of drinking during pregnancy and fatty acid ethyl esters of alcohol in meconium specimens obtained from a subsample of newborns from this cohort (Bearer et al., 2003). Diagnoses of FAS at 5 years also showed a dose-dependent relation between the maternal reports obtained during pregnancy and the subsequent severity of the diagnosis (Jacobson et al., 2008), thereby further strengthening the validity of the maternal self-report measure. In this cohort of infants from an urban socioeconomically disadvantaged community in Cape Town characterized by heavy prenatal alcohol use, it is of particular interest that competence in symbolic play was associated independently with both alcohol exposure in utero and quality of parenting. These data suggest that even infants whose symbolic play development is adversely affected by prenatal exposure may benefit from input from a responsive caregiver who uses play materials to provide appropriate stimulation.

7,25 The recognition

of cells by the immune system when u

7,25 The recognition

of cells by the immune system when undergoing redox stress is not well buy AG-014699 defined. Our data suggest that cells undergoing a redox stress that leads to a lowering in the levels of intracellular glutathione may begin to display MHC class I dimers on their cell surface. Such alterations in cellular glutathione levels have been reported to occur during T-cell activation26,27 and also during apoptosis.17,18,28 A more extensive study monitoring both MHC class I dimer formation and the level of glutathione in cells undergoing a variety of stimuli would, we consider, be of some worth. Furthermore, distinguishing whether both apoptotic and necrotic cell death pathways induce dimers would also be informative, alongside other pathological states such as viral infection, PF-02341066 manufacturer and many others that induce inflammatory responses and the production of reactive oxygen species. This would allow a pattern of conditions to be catalogued under which MHC class I dimer formation is induced. Although various MHC class I dimers have been reported in the literature, their potential biological role remains enigmatic.8,13 Of significant note, however, are the observations that Ig-MHC class I dimers can act to tolerize T cells.29 In this study, Kourilsky and colleagues used a soluble H2-Kd molecule dimerized with a cross-linking antibody to demonstrate

that an antigen-specific T-cell hybridoma was initially activated, followed by a state of unresponsiveness. It has also been demonstrated that antigen-specific occupancy of just one of the two peptide-binding grooves in an

Isoconazole MHC class I dimer can have an effect on T cells,30 which may allow not only the HLA-B dimers we show here, but also the HLA-A-B dimers we describe in Fig. 2 to have some biological activity. Hence, the MHC class I dimers detected on apoptotic cells, and also on exosomes,15 may be capable of providing signal, including tolerogenic signals to immune cells. Similarly, tumour cells undergoing apoptosis, or releasing exosomes containing tumour-associated or tumour-specific antigens may influence T-cell behaviour. Of further interest is the possible recognition of MHC class I dimers by members of the NK cell receptor family. It has been shown that a disulphide-linked engineered version of the KIR2DL1 receptor has an increased affinity for HLA-C,31 and that KIR molecules can form an array of dimers and multimers in a zinc-dependent interaction.32 Hence interactions between dimers of both ligands and receptors may occur, potentially inducing extra stability for the generation of either inhibitory or activatory signals. As indicated above, defining the various conditions under which such dimers form would allow the design of experiments to directly study their potential influence on immune responses.

This led to the upregulation of IFN-stimulated genes known to enh

This led to the upregulation of IFN-stimulated genes known to enhance host resistance to virus infection [8-12]. “K” ODN also upregulate the expression of IL-6, which contributes to the activation of multiple pro-inflammatory genes check details and the subsequent shift from

innate to adaptive immunity [8-12]. The current study was designed to identify the key signaling pathway(s) responsible for the upregulation of IFN-β and IL-6, as these would provide important insights into the pattern of “K” ODN mediated activation of human pDCs. Previous efforts to examine the signaling cascade(s) triggered by the interaction of TLR9 with CpG DNA focused primarily on murine myeloid DCs (mDCs), monocytes, and macrophages [13]. Studies examining the regulation of IL-6 by “K” ODN in mice documented a role for interferon regulatory factor-5 (IRF-5) and the binding of the NF-κB transcription factors p50/p65/c-Rel to the IL-6 promoter [14, 15], while IRF-1 was identified as a key mediator of IFN-β induction by “K” ODN [16]. Yet, there is reason to question whether those findings are applicable to human pDC, as there are fundamental differences in the signaling cascades utilized by mDCs versus pDCs and mice versus humans [2, 13, 17-20]. The rarity of pDCs in human peripheral blood (they constitute only 0.2–0.5% of the PBMC pool) and ease with which they become activated during the purification process

complicates their use [6, 7]. Thus, studies of human pDCs were supplemented by analyses of the human CAL-1 pDC-like cell line to provide novel insights into the regulation of TLR9-mediated activation of human pDCs. CAL-1 cells express TLR9 and mirror the response of primary human selleckchem pDCs to CpG ODN, as reflected by similar patterns of cytokine induction [12, 21, 22]. siRNA knockdown studies identified the transcription factors IRF-5 and NF-κB p50 as key early regulators of both IL-6 and IFN-β gene expression in CAL-1 cells. Proximity ligation assays (PLAs) demonstrated Monoiodotyrosine that IRF-5 and NF-κB p50 but not p65 significantly co-localized within the nucleus of these cells within 30

min of stimulation, consistent with these factors cooperatively mediating gene expression. In contrast to data derived from murine studies, IRF-8 was identified as a negative regulator of IFN-β and IL-6 expression, indicating that IRF-5 and IRF-8 compete to control gene expression following “K” ODN stimulation in human pDCs. This work also demonstrates that endogenous IRF-5 and IRF-7 are associated with MyD88 in resting CAL-1 cells but stimulation with “K” ODN leads to the activation only of IRF-5. As IRF-5 and IRF-8 variants are associated with autoimmune diseases such as lupus [23-28], these findings are relevant to our understanding of the pharmacologic effects of “K” ODN and the role of TLR9 ligation under physiologic, pathologic, and therapeutic conditions. CAL-1 cells share many phenotypic and functional properties of human pDCs [12, 21, 22].