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Node Cells (node + cell)
Kinds of Node Cells Terms modified by Node Cells Selected AbstractsSustained Inward Current and Pacemaker Activity of Mammalian Sinoatrial NodeJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 8 2002HENGGUI ZHANG Ph.D. Sustained Inward Current in the Sinoatrial Node.Introduction: A novel sustained inward Na+ current ist, which sensitive to Ca2+ -antagonists and potentiated by beta-adrenergic stimulation, has been described in pacemaker cells of rabbit, guinea pig, and rat sinoatrial node, as well as rabbit AV node. Although ist has been suggested to be an important pacemaker current, this has never been tested experimentally because of the lack of a specific blocker. In this study, we address the role of ist in the pacemaker activity of the sinoatrial node cell using computer models. Methods and Results: The newly developed models of Zhang et al. for peripheral and central rabbit sinoatrial node cells and models of Noble and Noble, Demir et al., Wilders et al., and Dokos et al. for typical rabbit sinoatrial node cells were modified to incorporate equations for ist. The conductance gst was chosen to give a current density-voltage relationship consistent with experimental data. In the models of Zhang et al. (periphery), Noble and Noble, and Dokos et al., in which ist was smaller or about the same amplitude as other inward currents, ist increased the pacemaking rate by 0.6%, 2.2%, and 0.8%, respectively. In the models of Zhang et al. (center), Demir et al., and Wilders et al., in which ist was larger than some other inward ionic currents, ist increased the pacemaking rate by 7%, 20%, and 14%, respectively. Conclusion: ist has the potential to be a regulator of pacemaker activity, although its importance will depend on the amplitude of ist relative to the amplitude of other inward currents involved in pacemaker activity. [source] Morphogenesis of the node and notochord: The cellular basis for the establishment and maintenance of left,right asymmetry in the mouseDEVELOPMENTAL DYNAMICS, Issue 12 2008Jeffrey D. Lee Abstract Establishment of left,right asymmetry in the mouse embryo depends on leftward laminar fluid flow in the node, which initiates a signaling cascade that is confined to the left side of the embryo. Leftward fluid flow depends on two cellular processes: motility of the cilia that generate the flow and morphogenesis of the node, the structure where the cilia reside. Here, we provide an overview of the current understanding and unresolved questions about the regulation of ciliary motility and node structure. Analysis of mouse mutants has shown that the motile cilia must have a specific structure and length, and that they must point posteriorly to generate the necessary leftward fluid flow. However, the precise structure of the motile cilia is not clear and the mechanisms that position cilia on node cells have not been defined. The mouse node is a teardrop-shaped pit at the distal tip of the early embryo, but the morphogenetic events that create the mature node from cells derived from the primitive streak are only beginning to be characterized. Recent live imaging experiments support earlier scanning electron microscopy (SEM) studies and show that node assembly is a multi-step process in which clusters of node precursors appear on the embryo surface as overlying endoderm cells are removed. We present additional SEM and confocal microscopy studies that help define the transition stages during node morphogenesis. After the initiation of left-sided signaling, the notochordal plate, which is contiguous with the node, generates a barrier at the embryonic midline that restricts the cascade of gene expression to the left side of the embryo. The field is now poised to dissect the genetic and cellular mechanisms that create and organize the specialized cells of the node and midline that are essential for left,right asymmetry. Developmental Dynamics 237:3464,3476, 2008. © 2008 Wiley-Liss, Inc. [source] The role of the ICOS/B7RP-1 T cell costimulatory pathway in murine experimental autoimmune uveoretinitisEUROPEAN JOURNAL OF IMMUNOLOGY, Issue 11 2006Yoshihiko Usui Abstract ICOS/B7RP-1 is a new member of the CD28/B7 family of costimulatory molecules and plays differential roles in autoimmune diseases. In this study, we examined the role of ICOS/B7RP-1 pathway in the pathogenesis of mouse experimental autoimmune uveoretinitis (EAU), an animal model of human autoimmune uveitis. ICOS expression was found on infiltrating CD4+ T cells in the region of the retina in EAU-induced mice. The anti-B7RP-1 monoclonal antibody (mAb)-treated or ICOS-deficient mice showed a substantial reduction of disease scores. Blockade of ICOS/B7RP-1 interaction during the effector phase ameliorated the disease, whereas its blockade during the induction phase exhibited no significant effect. Moreover, administration of anti-B7RP-1 mAb effectively ameliorated the disease induced by adoptive transfer of pathogenic T cells. The anti-B7RP-1 mAb treatment inhibited the expansion and/or effector function of pathogenic T cells, given that proliferative response and IFN-, production by lymph node cells were reduced upon restimulation with the antigen peptide in vitro. These results suggest that the ICOS/B7RP-1 interaction plays a critical role in the pathogenesis of uveitis. We also indicated that ICOS-mediated costimulation plays differential roles in EAU and experimental autoimmune encephalomyelitis, which is also a Th1 disease induced in the same manner as EAU. [source] Intraocular injection of tamoxifen-loaded nanoparticles: a new treatment of experimental autoimmune uveoretinitisEUROPEAN JOURNAL OF IMMUNOLOGY, Issue 12 2004Yvonne de Kozak Abstract In this study, we tested the efficiency of an intravitreal injection of tamoxifen, a non-steroidal estrogen receptor modulator, in retinal soluble antigen (S-Ag)-induced experimental autoimmune uveoretinitis (EAU). To increase the bioavailability of tamoxifen, we incorporated tamoxifen into polyethylene glycol (PEG)-coated nanoparticles (NP-PEG-TAM). The localization of the nanoparticles within the eye was investigated using fluorescent-labeled PEG-coated nanoparticles after injection into the vitreous cavity of rats with EAU. Some nanoparticles were distributed extracellularly throughout the ocular tissues, others were concentrated in resident ocular cells and in infiltrating macrophages. Whereas the injection of free tamoxifen did not alter the course of EAU, injection of NP-PEG-TAM performed 1,2,days before the expected onset of the disease in controls resulted in significant inhibition of EAU. NP-PEG-TAM injection significantly reduced EAU compared to injection of NP-PEG-TAM with 17,-estradiol (E2), suggesting that tamoxifen is acting as a partial antagonist to E2. Diminished infiltration by MHC class,II+ inflammatory cells and low expression of TNF-,, IL-1,, and RANTES mRNA were noted in eyes of NP-PEG-TAM-treated rats. Intravitreal injection of NP-PEG-TAM decreased S-Ag lymphocyte proliferation, IFN-, production by inguinal lymph node cells, and specific delayed-type hypersensitivity indicative of a reduced Th1-type response. It increased the anti-S-Ag IgG1 isotype indicating an antibody class switch to Th2 response. These data suggest that NP-PEG-TAM inhibition of EAU could result from a form of immune deviation. Tamoxifen-loaded nanoparticles may represent a new option for the treatment of experimental uveitis. [source] Notch1 expression on T,cells is not required for CD4+ T,helper differentiationEUROPEAN JOURNAL OF IMMUNOLOGY, Issue 6 2004Fabienne Tacchini-Cottier Abstract Notch1 proteins are involved in binary cell fate decisions. To determine the role of Notch1 in the differentiation of CD4+ Th1 versus Th2 cells, we have compared T,helper polarization in vitro in naive CD4+ T,cells isolated from mice in which the N1 gene is specifically inactivated in all mature T,cells. Following activation, Notch1-deficient CD4+ T,cells transcribed and secreted IFN-, under Th1 conditions and IL-4 under Th2 conditions at levels similar to that of control CD4+ T,cells. These results show that Notch1 is dispensable for the development of Th1 and Th2 phenotypes in vitro. The requirement for Notch1 in Th1 differentiation in vivo was analyzed following inoculation of Leishmania major in mice with a T,cell-specific inactivation of the Notch1 gene. Following infection, these mice controlled parasite growth at the site of infection and healed their lesions. The mice developed a protective Th1 immune response characterized by high levels of IFN-, mRNA and protein and low levels of IL-4 mRNA with no IL-4 protein in their lymph node cells. Taken together, these results indicate that Notch1 is not critically involved in CD4+ T,helper,1 differentiation and in resolution of lesions following infection with L.,major. [source] Characterization of CC-chemokine receptor 7 expression on murine T cells in lymphoid tissuesIMMUNOLOGY, Issue 2 2003Olle Bjorkdahl Summary Expression of the lymph node homing and CC-chemokine receptor 7 (CCR7), with L-selectin (CD62L), has been shown to divide human memory T cells into two functionally distinct subsets. We generated a polyclonal antibody against murine CCR7 and used this antibody to study CCR7 expression on murine T-cell subsets. Using flow cytometric staining of T cells for visualisation expression of CCR7 in association with CD62L and CD44, a major population of CD4 or CD8 T cells expressing CCR7 were found to be CD62Lhigh CD44low, which would suggest a naïve cell phenotype. By analogy with human studies, memory cells could be subdivided into CCR7high CD62Lhigh CD44high (central memory) and CCR7low CD62Llow CD44high (effector memory). The proportions of these populations were different in lymph node, blood and spleen. Functional, short-term in vitro polyclonal stimulation of blood, spleen and lymph node cells from naive mice demonstrated that CCR7high CD4 T cells produced predominantly interleukin (IL)-2, whereas CCR7low CD4 T cells produced both IL-2 and interferon-, (IFN-,). However, in contrast to previously published reports, the CCR7high CD8 T-cell subpopulation produced both IFN-, and IL-2. Analysis of effector T cells, induced by immunization in vivo, showed that a proportion of activated naïve CD4 T cells down-regulated CCR7 only after multiple cell divisions, and this coincided with the down-regulation of CD62L and production of IL-4 and IFN-,. Finally, analysis of effector T cells during the phase of maximal clonal expansion of secondary immune responses in vivo indicated that the vast majority of both IL-2- and IFN-,-producing cells are CCR7low, while few cytokine-expressing CCR7high T cells were detected. Our results support the hypothesis, developed from studies with human cells, that CCR7 may separate functionally different murine memory T-cell subpopulations, but indicate additional complexity in that CCR7high CD8 T cells also may produce IFN-,. [source] Targeting TGF-,1 by employing a vaccine ameliorates fibrosis in a mouse model of chronic colitisINFLAMMATORY BOWEL DISEASES, Issue 6 2010Yanbing Ma MSc Abstract Background: Intestinal fibrosis and stricture formation are major complications of inflammatory bowel disease (IBD), for which there are currently few effective treatments. We sought to investigate whether targeting transforming growth factor-beta1 (TGF-,1), a key profibrotic mediator, with a peptide-based virus-like particle vaccine would be effective in suppressing intestinal fibrosis by using a mouse model of 2,4,6-trinitrobenzene sulfonic acid (TNBS)-induced chronic colitis. Methods: The vaccine was prepared by inserting a peptide derived from mouse TGF-,1 into a carrier hepatitis B core antigen using gene recombination methods. Chronic colitis was induced in BALB/c mice by 8 weekly TNBS administrations. Mice were subcutaneously injected with vaccine, carrier, or phosphate-buffered saline (PBS) in 2 separate studies: either before or after acute inflammatory responses commenced. Results: Sera from vaccinated mice exhibited significantly elevated levels of TGF-,1-specific immunoglobulin G (IgG), which inhibited TGF-,1-induced luciferase production in mink lung epithelial cells. In the chronic colitis model, mice receiving vaccine showed improved body weight gain and significantly reduced colonic collagen deposition. Hematoxylin and eosin staining and semiquantitative scoring indicated that vaccination even ameliorated colonic inflammation. Cytokine profile analysis revealed that levels of TGF-,1, interleukin (IL)-17, and IL-23 in vaccinated mouse colon tissues were decreased, and that percentages of IL-17-expressing CD4+ lymphocytes in mesenteric lymph node cells were reduced. Furthermore, Smad3 phosphorylation, a key event in TGF-, signaling, was decreased in colonic tissue in vaccinated mice. Conclusions: This TGF-,1 peptide-based vaccine, which suppressed excessive TGF-,1 bioactivity, may prevent the development of intestinal fibrosis and associated complications, presenting a novel approach in the treatment of IBD. (Inflamm Bowel Dis 2010) [source] Lactobacillus plantarum 299V in the treatment and prevention of spontaneous colitis in interleukin-10-deficient miceINFLAMMATORY BOWEL DISEASES, Issue 2 2002Michael Schultz Abstract Interleukin (IL)-10-deficient (IL-10,/,) mice develop colitis under specific pathogen-free (SPF) conditions and remain disease free if kept sterile (germ free [GF]). We used four different protocols that varied the time-points of oral administration of Lactobacillus plantarum 299v (L. plantarum) relative to colonization with SPF bacteria to determine whether L. plantarum could prevent and treat colitis induced by SPF bacteria in IL-10,/, mice and evaluated the effect of this probiotic organism on mucosal immune activation. Assessment of colitis included blinded histologic scores, measurements of secreted colonic immunoglobulin isotypes, IL-12 (p40 subunit), and interferon (IFN)-, production by anti-CD3-stimulated mesenteric lymph node cells. Treating SPF IL-10,/, mice with L. plantarum attenuated previously established colonic inflammation as manifested by decreased mucosal IL-12, IFN-,, and immunoglobulin G2a levels. Colonizing GF animals with L. plantarum and SPF flora simultaneously had no protective effects. Gnotobiotic IL-10,/, mice monoassociated with L. plantarum exhibited mild immune system activation but no colitis. Pretreatment of GF mice by colonization with L. plantarum, then exposure to SPF flora and continued probiotic therapy significantly decreased histologic colitis scores. These results demonstrate that L. plantarum can attenuate immune-mediated colitis and suggest a potential therapeutic role for this agent in clinical inflammatory bowel diseases. [source] Resolution of skeletal muscle inflammation in mdx dystrophic mouse is accompanied by increased immunoglobulin and interferon-, productionINTERNATIONAL JOURNAL OF EXPERIMENTAL PATHOLOGY, Issue 3 2002Jussara Lagrota-Candido Summary. Mdx mouse, the animal model of Duchenne muscular dystrophy, develops an X-linked recessive inflammatory myopathy with an apparent sustained capacity for muscle regeneration. We analysed whether changes in the skeletal muscle during myonecrosis and regeneration would correlate with functional alterations in peripheral lymphoid tissues. Here we show that during the height of myonecrosis, mdx mice display marked atrophy of peripheral lymph nodes and extensive muscle inflammation. In contrast, enlargement of draining lymph nodes with accumulation of CD4+ CD44+, CD4+ CD25+, CD8+ CD44+ T lymphocytes and type-2 B cells was consistently observed during amelioration of the muscle lesion. In addition, regeneration of the muscular tissue was accompanied by concomitant increase of immunoglobulin-secreting cells in regional lymph nodes and bone marrow. Double immunolabelling analysis revealed intense B cell proliferation and formation of germinal centre in the follicles of dystrophic regional lymph nodes. Furthermore, lymph node cells produced large amounts of IFN-, but not IL-4, IL-6 or IL-10 after in vitro mitogen stimulation with Concanavalin A. As these alterations occurred mainly during the recovery period, we suggested that local activation of the immune system could be an influence which mitigates the myonecrosis of muscular tissue in the mdx dystrophic mouse. [source] Popliteal lymph node assay: facts and perspectivesJOURNAL OF APPLIED TOXICOLOGY, Issue 6 2005Guillaume Ravel Abstract The popliteal lymph node assay (PLNA) derives from the hypothesis that some supposedly immunemediated adverse effects induced by certain pharmaceuticals involve a mechanism resembling a graft-versus-host reaction. The injection of many but not all of these compounds into the footpad of mice or rats produces an increase in the weight and/or cellularity of the popliteal lymph node in the treated limb (direct PLNA). Some of the compounds known to cause these adverse effects in humans, however, failed to induce a positive PLNA response, leading to refinements of the technique to include pretreatment with enzyme inducers, depletion of CD4+ T cells or additional endpoints such as histological examination, lymphocyte subset analysis and cytokine fingerprinting. Alternative approaches have been used to improve further the predictability of the assay. In the secondary PLNA, the test compound is injected twice in order to illicit a greater secondary response, thus suggesting a memory-specific T cell response. In the adoptive PLNA, popliteal lymph node cells from treated mice are injected into the footpad of naive mice; a marked response to a subsequent footpad challenge demonstrates the involvement of T cells. Finally, the reporter antigens TNP-Ficoll and TNP-ovalbumin are used to differentiate compounds that induce responses involving neo-antigen help or co-stimulatory signals (modified PLNA). The PLNA is increasingly considered as a tool for detection of the potential to induce both sensitization and autoimmune reactions. A major current limitation is validation. A small inter-laboratory validation study of the direct PLNA found consistent results. No such study has been performed using an alternative protocol. Other issues include selection of the optimal protocol for an improved prediction of sensitization vs autoimmunity, and the elimination of false-positive responses due to primary irritation. Finally, a better understanding of underlying mechanisms is essential to determine the most relevant endpoints. The confusion resulting from use of the PLNA to predict autoimmune-like reactions as well as sensitization should be clarified. Interestingly, most drugs that were positive in the direct PLNA are also known to cause drug hypersensitivity syndrome in treated patients. This observation is expected to open new avenues of research. Copyright © 2005 John Wiley & Sons, Ltd. [source] Methods for the identi,cation of chemical respiratory allergens in rodents: comparisons of cytokine pro,ling with induced changes in serum IgEJOURNAL OF APPLIED TOXICOLOGY, Issue 4 2003R. J. Dearman Abstract No validated or widely recognized test methods are currently available for the prospective identi,cation of chemicals with the potential to cause respiratory allergy. The cellular and molecular mechanisms that result in the induction of chemical sensitization of the respiratory tract are unclear, although there is evidence for the selective development of T helper 2 (Th2)-type responses and, in some cases, the production of IgE antibody. We have therefore examined the utility of cytokine pro,ling using BALB/c mice, together with the measurement of induced increases in the total serum concentration of IgE in the Brown Norway (BN) rat, as markers for the prospective identi,cation of chemical respiratory allergens. Responses provoked by the reference respiratory allergen trimellitic anhydride (TMA) have been compared with those stimulated by the respiratory sensitizing diisocyanates toluene diisocyanate (TDI) and hexamethylene diisocyanate (HDI) and by the acid anhydride hexahydrophthalic anhydride (HHPA). Topical exposure of BN rats to TMA, TDI and HHPA each provoked marked immune activation (increases in lymph node cellularity and proliferation). However, only treatment with TMA stimulated vigorous increases in the total serum concentration of IgE. In contrast, exposure to HHPA, TDI or HDI failed to provoke signi,cant changes in serum IgE concentration or induced only transient and relatively weak increases in serum IgE levels. In parallel experiments using BALB/c strain mice, however, topical application of all four chemical respiratory allergens provoked a marked Th2-type cytokine secretion pro,le in draining lymph node cells. These data suggest that the measurement of induced changes in serum IgE is not suf,ciently sensitive for the robust identi,cation of chemical respiratory allergens. Furthermore, irrespective of the reasons for variations in TMA-induced IgE production among BN rats, doubts remain regarding the utility of these animals for the characterization of immune responses to chemical allergens. Cytokine pro,ling using the BALB/c strain mouse apparently provides a more robust method for the hazard assessment of chemical respiratory allergens. Copyright © 2003 John Wiley & Sons, Ltd. [source] One-Dimensional Rabbit Sinoatrial Node Models:JOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 2003Benefits, Limitations Introduction: Cardiac multicellular modeling has traditionally focused on ventricular electromechanics. More recently, models of the atria have started to emerge, and there is much interest in addressing sinoatrial node structure and function. Methods and Results: We implemented a variety of one-dimensional sinoatrial models consisting of descriptions of central, transitional, and peripheral sinoatrial node cells, as well as rabbit or human atrial cells. These one-dimensional models were implemented using CMISS on an SGI® Origin® 2000 supercomputer. Intercellular coupling parameters recorded in experimental studies on sinoatrial node and atrial cell-pairs under-represent the electrotonic interactions that any cardiomyocyte would have in a multidimensional setting. Unsurprisingly, cell-to-cell coupling had to be scaled-up (by a factor of 5) in order to obtain a stable leading pacemaker site in the sinoatrial node center. Further critical parameters include the gradual increase in intercellular coupling from sinoatrial node center to periphery, and the presence of electrotonic interaction with atrial cells. Interestingly, the electrotonic effect of the atrium on sinoatrial node periphery is best described as opposing depolarization, rather than necessarily hyperpolarizing, as often assumed. Conclusion: Multicellular one-dimensional models of sinoatrial node and atrium can provide useful insight into the origin and spread of normal cardiac excitation. They require larger than "physiologic" intercellular conductivities in order to make up for a lack of "anatomical" spatial scaling. Multicellular models for more in-depth quantitative studies will require more realistic anatomico-physiologic properties. (J Cardiovasc Electrophysiol, Vol. 14, pp. S121-S132, October 2003, Suppl.) [source] Sustained Inward Current and Pacemaker Activity of Mammalian Sinoatrial NodeJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 8 2002HENGGUI ZHANG Ph.D. Sustained Inward Current in the Sinoatrial Node.Introduction: A novel sustained inward Na+ current ist, which sensitive to Ca2+ -antagonists and potentiated by beta-adrenergic stimulation, has been described in pacemaker cells of rabbit, guinea pig, and rat sinoatrial node, as well as rabbit AV node. Although ist has been suggested to be an important pacemaker current, this has never been tested experimentally because of the lack of a specific blocker. In this study, we address the role of ist in the pacemaker activity of the sinoatrial node cell using computer models. Methods and Results: The newly developed models of Zhang et al. for peripheral and central rabbit sinoatrial node cells and models of Noble and Noble, Demir et al., Wilders et al., and Dokos et al. for typical rabbit sinoatrial node cells were modified to incorporate equations for ist. The conductance gst was chosen to give a current density-voltage relationship consistent with experimental data. In the models of Zhang et al. (periphery), Noble and Noble, and Dokos et al., in which ist was smaller or about the same amplitude as other inward currents, ist increased the pacemaking rate by 0.6%, 2.2%, and 0.8%, respectively. In the models of Zhang et al. (center), Demir et al., and Wilders et al., in which ist was larger than some other inward ionic currents, ist increased the pacemaking rate by 7%, 20%, and 14%, respectively. Conclusion: ist has the potential to be a regulator of pacemaker activity, although its importance will depend on the amplitude of ist relative to the amplitude of other inward currents involved in pacemaker activity. [source] Suppression of immune responses to ,-lactoglobulin in mice by the oral administration of peptides representing dominant T cell epitopesJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 3 2008Koko Mizumachi Abstract BACKGROUND: The significance of oral tolerance in the treatment of adverse immune reactions such as allergic and autoimmune diseases has been noted. In the present study, peptides that could effectively induce oral tolerance to bovine ,-lactoglobulin (BLG), a milk allergen, were investigated in a murine model. RESULTS: The oral administration of peptides corresponding to the T cell epitope regions of BLG, i.e. p42,56, p62,76 and p139,154, apparently down-regulated T cell proliferation to BLG. The in vitro cytokine production by the lymph node cells from the peptide-fed mice cultured in the presence of the antigen was also analysed. It was found that p62,76 and p139,154 feeding suppressed the production of both Th1 and Th2 types. Interestingly, p139,154 feeding suppressed both T cell and antibody responses to BLG. Additionally, p139,154 feeding diminished BLG-specific IgE and IgG1 antibody responses. CONCLUSION: The unique tolerogen peptide p139,154 that could suppress both T and B cell responses to BLG in a murine model was identified. These findings can be useful for the selection of an optimum tolerogenic peptide to prevent and treat milk and other food allergies. Copyright © 2007 Society of Chemical Industry [source] Influence of a cocoa-enriched diet on specific immune response in ovalbumin-sensitized ratsMOLECULAR NUTRITION & FOOD RESEARCH (FORMERLY NAHRUNG/FOOD), Issue 3 2009Teresa Pérez-Berezo Abstract Previous studies in young rats have reported the impact of 3 weeks of high cocoa intake on healthy immune status. The present article describes the effects of a longer-term cocoa-enriched diet (9 weeks) on the specific immune response to ovalbumin (OVA) in adult Wistar rats. At 4 weeks after immunization, control rats produced anti-OVA antibodies, which, according their amount and isotype, were arranged as follows: IgG1 > IgG2a > IgM > IgG2b > IgG2c. Both cocoa diets studied (4% and 10%) down-modulated OVA-specific antibody levels of IgG1 (main subclass associated with the Th2 immune response in rats), IgG2a, IgG2c and IgM isotypes. Conversely, cocoa-fed rats presented equal or higher levels of anti-OVA IgG2b antibodies (subclass linked to the Th1 response). Spleen and lymph node cells from OVA-immunized control and cocoa-fed animals proliferated similarly under OVA stimulation. However, spleen cells from cocoa-fed animals showed decreased interleukin-4 secretion (main Th2 cytokine), and lymph node cells from the same rats displayed higher interferon-, secretion (main Th1 cytokine). These changes were accompanied by a reduction in the number of anti-OVA IgG-secreting cells in spleen. In conclusion, cocoa diets induced attenuation of antibody synthesis that may be attributable to specific down-regulation of the Th2 immune response. [source] Isolates of Trichuris muris elicit different adaptive immune responses in their murine hostPARASITE IMMUNOLOGY, Issue 3 2005C. E. Johnston SUMMARY The J and S isolates of Trichuris muris have different infection profiles in C57BL/6 mice; J worms are expelled, S worms survive to chronicity. Building on this, the ability of the J and S isolates to survive, and the quality of the immune response induced was explored in three different strains of mouse. The resistant BALB/c mouse mounted a strong Th2 response against both isolates, which were quickly expelled. The susceptible AKR host mounted a Th1 response and retained both isolates. Despite equivalent worm exposure, mesenteric lymph node cells from AKR mice infected with the S isolate produced significantly higher levels of IL-12 and the intestinal mastocytosis was reduced. IgG1 and IgG2a from S-infected AKR mice recognized low molecular weight antigens not recognized by J-infected mice. Differential expulsion kinetics was observed in the slower-responding C57BL/6 strain; J worms were expelled but S isolate worms were retained. Survival of the S isolate was again associated with elevated IL-12 and decreased Th2 responses. In resistant mouse strains, the outcome of infection is thus dominantly influenced by host genetics. However, in the slower-responding host, isolate-derived factors may play a role in shaping the quality of the adaptive immune response, thus influencing parasite survival. [source] Th2 polarization of the immune response of BALB/c mice to Ixodes ricinus instars, importance of several antigens in activation of specific Th2 subpopulationsPARASITE IMMUNOLOGY, Issue 2 2001Naceur Mejri BALB/c mice were infested with Ixodes ricinus larvae, nymphs or adults. Expression of IL-4 and IFN-, mRNA in axillary and brachial draining lymph node cells were measured by competitive quantitative reverse transcription-polymerase chain reaction 9 days after the beginning of primary-infestation. IL-4 mRNA was always higher than that of IFN-, mRNA for all tick instars. Moreover, IL-4 mRNA expression progressively increased during nymphal primary-infestation with a high burst of expression 7 days after the beginning of infestation. No evolution of IFN-, mRNA expression was detected. Draining lymph node cells of infested BALB/c produced higher level of IL-4 than IFN-, following in vitro restimulation with adult tick saliva, salivary gland extract (SGE) or with five selected different chromatographic fractions of SGE. Anti-tick IgG1 antibodies but no IgG2a were detected in BALB/c pluri-infested with I. ricinus nymphs, which confirmed the Th2 polarization of the immune response. [source] Gender differences in transcriptional regulation of IL-5 expression by bronchial lymph node cells in a mouse model of asthmaRESPIROLOGY, Issue 4 2010Kana WADA ABSTRACT Background and objective: The severity of asthma after puberty is higher in women than in men. Increased numbers of eosinophils in the airways of female mice after antigen challenge was associated with increased levels of T helper (Th)2 cytokines at the site of inflammation, and in human and mouse studies, the profile of cytokines produced by immune cells from women showed greater Th2 predominance. The aim of this study was to investigate gender differences in the development of Th2 immune responses. Methods: Male and female C57BL/6 mice were sensitized with ovalbumin. Cells prepared from bronchial lymph nodes were cultured in the absence or presence of ovalbumin. Cytokine concentrations in the culture supernatants were measured, and IL-5 and GATA-binding protein 3 (GATA-3) gene expression were evaluated. T-cell subsets were analysed using specific surface markers. Results: The concentrations of IL-4, IL-5, IL-13 and IL-10, but not interferon-, or transforming growth factor-,1, were higher in cell supernatants from female mice than in those from male mice. IL-5 and GATA-3 gene expressions were higher in cells from women than in cells from men. The numbers of CD3+CD4+T1/ST2+ cells, but not CD3+CD4+ or CD4+CD25+ cells, were significantly higher in cells from women than in cells from men. Conclusions: Greater antigen-induced Th2 cytokine production by bronchial lymph node cells from female mice was associated with enhanced Th2 cell differentiation and increased expression of the Th2-specific transcription factor, GATA-3. [source] Vascular endothelial growth factor receptor tyrosine kinase inhibitor PTK787/ZK 222584 inhibits both the induction and elicitation phases of contact hypersensitivityTHE JOURNAL OF DERMATOLOGY, Issue 7 2007Aisaku YAMAMOTO ABSTRACT Vascular endothelial growth factor (VEGF) and its endothelial cell receptors (VEGFR) have been shown to be involved in the pathogenesis of the contact hypersensitivity (CHS) reaction. Previous studies have demonstrated that anti-VEGFR-2 antibody significantly suppresses the elicitation phase of CHS but does not affect the induction phase. PTK787/ZK 222584 (1-[4-chloroanilino]-4-[4-pyridylmethyl] phthalazine succinate; PTK/ZK) is a potent inhibitor of VEGFR tyrosine kinases. To test the effect of PTK/ZK on the induction and elicitation phases of CHS separately, we used an established method of CHS assay-sensitization and challenge in BALB/c mice. Either 50 mg/kg/day PTK/ZK or vehicle serving as a control was administered orally in the induction or elicitation phases separately. In the afferent phase, flow cytometry of skin-draining lymph node cells revealed that the migration of Langerhans cells was suppressed in the mice treated with PTK/ZK at sensitization. The degrees of ear swelling at 24 and 48 h were significantly diminished in mice treated with PTK/ZK at sensitization (P < 0.05). In the efferent phase, the degrees of ear swelling at 24 h (P < 0.01) and 48 h (P < 0.05), ear blood flow at 24 and 48 h (P < 0.01), and production of VEGF in the epidermis at 24 h (P < 0.05) were significantly suppressed in mice treated with PTK/ZK at elicitation. These findings and previous demonstrations suggest that both VEGF R-1 and VEGF R-2 are needed during the induction phase, and that VEGFR-2 has a pivotal role in the elicitation phase of the CHS reaction. [source] Neural precursors attenuate autoimmune encephalomyelitis by peripheral immunosuppressionANNALS OF NEUROLOGY, Issue 3 2007Ofira Einstein MSc Objective Intracerebroventricular or intravenous (IV) injection of neural precursor cells (NPCs) attenuates experimental autoimmune encephalomyelitis (EAE), the animal model of multiple sclerosis. Although stem cell therapy was introduced initially for cell replacement, we examine here whether NPCs possess immunomodulatory effects. Methods We examined the effects of systemic administration of NPCs on central nervous system (CNS) inflammation in EAE and the interactions between NPCs and T cells in vitro and in vivo. Results IV NPC therapy decreased significantly CNS inflammation and tissue injury and attenuated the clinical severity of EAE. IV-injected NPCs could not be found in the CNS but were detected in lymphoid organs. Coculture experiments showed that NPCs inhibited the activation and proliferation of lymph node,derived T cells in response to CNS-derived antigens and to nonspecific polyclonal stimuli. The relevance of NPC/lymph node cell interactions in vivo was further demonstrated when lymph node cells obtained from IV NPC-treated mice exhibited poor encephalitogenicity on transfer to naive mice and caused a markedly milder EAE compared with those obtained from nontreated mice. Interpretation IV administration of neural precursors inhibits EAE by a peripheral immunosuppressive effect. Our findings suggest a profound bystander inhibitory effect of NPCs on T-cell activation and proliferation in the lymph nodes, leading to amelioration of EAE. Ann Neurol 2006 [source] Inhibition of synovial hyperplasia, rheumatoid T cell activation, and experimental arthritis in mice by sulforaphane, a naturally occurring isothiocyanateARTHRITIS & RHEUMATISM, Issue 1 2010Jin-Sun Kong Objective To investigate whether sulforaphane (SFN), an isothiocyanate derived from cruciferous vegetables such as broccoli, regulates synoviocyte hyperplasia and T cell activation in rheumatoid arthritis (RA). Methods Synoviocyte survival was assessed by MTT assay. The levels of Bcl-2, Bax, p53, and pAkt were determined by Western blot analysis. Cytokine concentrations in culture supernatants from mononuclear cells were analyzed by enzyme-linked immunosorbent assay. The in vivo effects of SFN were examined in mice with experimentally induced arthritis. Results SFN induced synoviocyte apoptosis by modulating the expression of Bcl-2/Bax, p53, and pAkt. In addition, nonapoptotic doses of SFN inhibited T cell proliferation and the production of interleukin-17 (IL-17) and tumor necrosis factor , (TNF,) by RA CD4+ T cells stimulated with anti-CD3 antibody. Anti-CD3 antibody,induced increases in the expression of retinoic acid,related orphan receptor ,t and T-bet were also repressed by SFN. Moreover, the intraperitoneal administration of SFN to mice suppressed the clinical severity of arthritis induced by injection of type II collagen (CII), the anti-CII antibody levels, and the T cell responses to CII. The production of IL-17, TNF,, IL-6, and interferon-, by lymph node cells and spleen cells from these mice was markedly reduced by treatment with SFN. Anti-CII antibody,induced arthritis in mice was also alleviated by SFN injection. Conclusion SFN was found to inhibit synovial hyperplasia, activated T cell proliferation, and the production of IL-17 and TNF, by rheumatoid T cells in vitro. The antiarthritic and immune regulatory effects of SFN, which were confirmed in vivo, suggest that SFN may offer a possible treatment option for RA. [source] Treatment of experimental arthritis by inducing immune tolerance with human adipose-derived mesenchymal stem cellsARTHRITIS & RHEUMATISM, Issue 4 2009Manuel A. González Objective Rheumatoid arthritis (RA) is a chronic autoimmune disease caused by loss of immunologic self tolerance and characterized by chronic joint inflammation. Adult mesenchymal stem cells (MSCs) were recently found to suppress effector T cell responses and to have beneficial effects in various immune disorders. The purpose of this study was to examine a new therapeutic strategy for RA based on the administration of human adipose-derived MSCs (AD-MSCs). Methods DBA/1 mice with collagen-induced arthritis were treated with human AD-MSCs after disease onset, and clinical scores were determined. Inflammatory response was determined by measuring the levels of different mediators of inflammation in the joints and serum. The Th1-mediated autoreactive response was evaluated by determining the proliferative response and cytokine profile of draining lymph node cells stimulated with the autoantigen. The number of Treg cells and the suppressive capacity on self-reactive Th1 cells were also determined. Results Systemic infusion of human AD-MSCs significantly reduced the incidence and severity of experimental arthritis. This therapeutic effect was mediated by down-regulating the 2 deleterious disease components: the Th1-driven autoimmune and inflammatory responses. Human AD-MSCs decreased the production of various inflammatory cytokines and chemokines, decreased antigen-specific Th1/Th17 cell expansion, and induced the production of antiinflammatory interleukin-10 in lymph nodes and joints. Human AD-MSCs also induced de novo generation of antigen-specific CD4+CD25+FoxP3+ Treg cells with the capacity to suppress self-reactive T effector responses. Conclusion Human AD-MSCs emerge as key regulators of immune tolerance by inducing the generation/activation of Treg cells and are thus attractive candidates for a cell-based therapy for RA. [source] Promotion of the local differentiation of murine Th17 cells by synovial macrophages during acute inflammatory arthritisARTHRITIS & RHEUMATISM, Issue 12 2008Paul J. Egan Objective To examine the generation of proinflammatory Th17 cells at the site of tissue inflammation and in draining lymph nodes using an interleukin-17 (IL-17),dependent model of acute inflammatory arthritis. Methods Arthritis was elicited in mice by intraarticular injection of methylated bovine serum albumin (mBSA) into the knee and subcutaneous injection of IL-1,. Anti,IL-17 or control antibodies were administered during arthritis induction. Cytokine expression was evaluated by intracellular cytokine staining of synovial lymphocytes, by polymerase chain reaction analysis of RNA extracted from lymph node cells, and by enzyme-linked immunosorbent assay of cell culture supernatants. Th17 differentiation of naive CD4+ T cells was assessed in cocultures with macrophages from arthritic mice. Results Anti,IL-17 antibody administered during acute arthritis markedly reduced disease, indicating that the model is IL-17 dependent. IL-17 messenger RNA (mRNA), but not protein, was detected in draining lymph node CD4+ T cells and preceded joint inflammation. In addition, mRNA for Th17 cell,stimulatory cytokines (transforming growth factor ,, IL-6) and Th17 cell,inhibitory cytokines (interferon-,, IL-4) was detected in lymph nodes following injection of mBSA and IL-1,. Th17 cells were clearly identified in the inflamed synovium at the peak of disease. Synovial macrophages supported Th17 cell generation from naive CD4+ T cell precursors stimulated via CD3 in vitro and produced high levels of IL-6. In contrast, peritoneal macrophages failed to induce Th17 cell differentiation and produced less IL-6. Conclusion These results suggest that Th17 cell differentiation is initiated in draining lymph nodes but that IL-17,producing cells are restricted to the inflamed synovium, being generated in response to local cytokines produced by inflammatory macrophages. [source] Acceleration of the onset of collagen-induced arthritis by a deficiency of platelet endothelial cell adhesion molecule 1ARTHRITIS & RHEUMATISM, Issue 11 2003Yoshifumi Tada Objective Platelet endothelial cell adhesion molecule 1 (PECAM-1; CD31) is a member of the immunoglobulin superfamily that is expressed in platelets, leukocytes, and endothelial cells. PECAM-1 has been shown to play a role in transendothelial migration of leukocytes and contains immunoreceptor tyrosine-based inhibitory motifs in its cytoplasmic tail and inhibits cellular responses. We examined the role of PECAM-1 in the development of collagen-induced arthritis (CIA). Methods CIA was induced in PECAM-1,deficient DBA/1 mice. The incidence of arthritis and the arthritis index were examined. Anti,type II collagen (anti-CII) antibody levels and interferon-, (IFN,) production by lymph node cells and spleen cells were determined. Lymphocytes from arthritic PECAM-1,deficient and wild-type mice were labeled with dye, transferred to arthritic PECAM-1+/, mice, and cell migration to inflamed joints was examined. Results PECAM-1,deficient mice showed accelerated onset of arthritis and increased severity only during the early phase. Anti-CII antibody levels were also increased during the early phase. IFN, production by lymph node cells and spleen cells from PECAM-1,deficient mice in response to CII was higher than that in wild-type mice. Lymphocytes from arthritic PECAM-1,deficient mice showed accelerated migration to inflamed joints, but not lymph nodes or spleen. The development of anti-CII antibody,induced arthritis was similar in PECAM-1,deficient and wild-type mice. Conclusion These results indicate that PECAM-1 negatively regulates humoral and cell-mediated immune responses and lymphocyte migration into joints and, consequently, the development of CIA. In addition, the role of PECAM-1 in the transendothelial migration of leukocytes appears to be redundant in this model. [source] Peptide-induced suppression of collagen-induced arthritis in HLA,DR1 transgenic miceARTHRITIS & RHEUMATISM, Issue 12 2002Linda K. Myers Objective To identify peptides capable of altering the immune response to type II collagen (CII) in the context of HLA,DR. Methods Immunizing mice transgenic for the human HLA,DRB1*0101 immune response gene with CII elicits an arthritis (collagen-induced arthritis [CIA]) that resembles rheumatoid arthritis. We have previously identified an immunodominant determinant of CII, CII (263,270), recognized by T cells in the context of DR1. To produce synthetic peptides with the potential of disrupting the DR1-restricted immune response, synthetic analog peptides were developed that contain site-directed substitutions in critical positions. These peptides were used to treat CIA in DR1 transgenic mice. Results An analog peptide, CII (256,276, N263, D266), that inhibited T cell responses in vitro, was identified. When DR1 mice were coimmunized with CII and CII (256,276, N263, D266), the incidence and severity of arthritis were greatly reduced, as was the antibody response to CII. Moreover, CII (256,276, N263, D266) was effective in down-regulating the immune responses to CII and arthritis, even when administered 2 weeks following immunization with CII. Spleen and lymph node cells from CII-immunized mice cultured with CII (256,276, N263, D266) in vitro produced increased amounts of interleukin-4 (IL-4) compared with cells cultured with the wild-type peptide, CII (256,276). Furthermore, CII (256,276, N263, D266) was incapable of preventing arthritis in DR1 IL-4,/, mice (genetically deficient in IL-4). Conclusion These data establish that CII (256,276, N263, D266) is a potent suppressor of the DR-mediated immune response to CII. Its effect is mediated, at least in part, by IL-4. These experiments represent the first description of an analog peptide of CII recognized by T cells in the context of a human major histocompatibility complex molecule that can suppress autoimmune arthritis. [source] Novel function of DUSP14/MKP6 (dual specific phosphatase 14) as a nonspecific regulatory molecule for delayed-type hypersensitivityBRITISH JOURNAL OF DERMATOLOGY, Issue 5 2007Y. Nakano Summary Background, Nonspecific unresponsive states of delayed-type hypersensitivity (DTH) to unrelated antigens are induced in mice by a single administration of hapten. In these studies, we found a unique regulatory mechanism of contact hypersensitivity (CHS) mediated by nonspecific suppressor factor (NSF) induced by the intravenous injection of hapten-conjugated syngeneic spleen cells. NSF is a , 45-kDa protein released from the macrophage-like suppressor cells and binds selectively to dendritic cells (DCs). Moreover, NSF-treated DCs release a second , 20-kDa NSF (NSFint). Objectives, To try and identify NSF and characterize its function. Methods, The suppressor activity was evaluated by inhibition of the passive transfer of CHS by the effector cells sensitized with hapten and the antigen-presenting cell (APC) activity of hapten-primed draining lymph node cells (DLNCs) to induce CHS. NSF-containing supernatants obtained from the culture of spleen cells from mice that had been injected intravenously with oxazolone-conjugated syngeneic spleen cells 7 days before were prepared and purified with a Green A dye-affinity column, DEAE column and Sephacryl S-200 column. Then, samples of molecular mass of , 45 kDa were separated by native-PAGE (polyacrylamide gel electrophoresis) and nonreducing sodium dodecyl sulphate (SDS)-PAGE. After confirming the suppressor activity of proteins of , 45 kDa separated by native-PAGE, samples were separated by nonreducing SDS-PAGE, transferred onto polyvinylidene difluoride membranes and analysed using matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry. Results, Proteins of , 45 kDa eluted from a Sephacryl S-200 column and the slice of native-PAGE gel exhibited the strong suppressor activity. Analyses using MALDI-TOF mass spectrometry and MASCOT algorithm of the protein bands around 45 kDa separated by nonreducing SDS-PAGE identified NSF as a 22·5-kDa protein, dual specific phosphatase 14/MAP-kinase phophatase-6 (DUSP14/MKP6), which functions as a negative regulator of the MAP-kinase signalling. Western blot analyses revealed that recombinant DUSP14 (rDUSP14) exists as the mixture of 22·5-kDa monomer and 45-kDa dimer under nonreducing conditions, and monomers under reducing conditions. Treatment with rDUSP14 at 4 °C for 2 h suppressed the ability of effector cells to transfer CHS dose dependently and the APC function of DLNCs to induce CHS. Epicutaneous application of rDUSP14 immediately after challenge inhibited the subsequent CHS expression. rDUSP14 was bound specifically by major histocompatibility complex class II (Ia)-positive spleen cells (presumably DCs). The suppressor activity of NSF was neutralized by anti-DUSP14 monoclonal antibody. Expression of DUSP14 mRNA in the spleen was upregulated parallel to the unresponsive state induced by hapten-conjugated cells. NSF, NSFint and rDUSP14 exhibited the phosphatase activity towards p -nitrophenyl phosphate in vitro as alkaline phosphatase. Conclusions, These studies indicate for the first time that NSF is a dimer of DUSP14 secreted by macrophage-like suppressor cells by stimulation with hapten-conjugated cells and exerts a regulatory function on CHS through DCs as a secreted phosphatase. [source] Endothelial stimulation by small lymphocytic lymphoma correlates with secreted levels of basic fibroblastic growth factorBRITISH JOURNAL OF HAEMATOLOGY, Issue 5 2003Lisa Rimsza Summary. Lymph nodes (LN) involved with small lympho- cytic lymphoma (SLL) reportedly contain increased numbers of microvessels that may constitute a therapeutic target in this disease. We investigated the secretion of the angiogenic growth factor, basic fibroblastic growth factor (bFGF), from primary tissue cultures of 15 LN with SLL and 10 reactive LN. bFGF was detected from the resulting conditioned media (CM) in 13/15 SLL samples (mean 92 ± 30, range 5,420 pg/ml) but was undetectable in CM from all reactive lymph nodes. CM was also used in a 72-h human umbilical vein endothelial cell (HUVEC) proliferation assay. HUVEC proliferation increased in the presence of SLL CM (70 ± 17%, range ,4,194%), proportional to secreted levels of bFGF (R2 = 0·95), and was reversed by depleting bFGF from CM. Previous SLL studies have examined either patient serum samples or paraffin-embedded lymph node tissue sections. This is the first study to examine the secretion of an angiogenic growth factor from primary cultures of lymph node cells. Our results indicate that bFGF is probably the primary mediator responsible for increased angiogenesis in involved nodes. These findings may be pertinent to future investigation into the mechanisms of increased angiogenesis in SLL. [source] | ||||||||||||||||||||||||||||