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Vitro Stimulation (vitro + stimulation)
Selected AbstractsLoss of FOXP3 expression in natural human CD4+CD25+ regulatory T cells upon repetitive in vitro stimulationEUROPEAN JOURNAL OF IMMUNOLOGY, Issue 4 2009Petra Hoffmann Abstract The adoptive transfer of CD4+CD25+ natural regulatory T cells (Treg) is a promising strategy for the treatment of autoimmune diseases and the prevention of alloresponses after transplantation. Clinical trials exploring this strategy require efficient in vitro expansion of this rare cell population. Protocols developed thus far rely on high-grade purification of Treg prior to culture initiation, a process still hampered by the lack of Treg cell-specific surface markers. Depletion of CD127+ cells was shown to separate activated conventional T cells from natural Treg cell populations allowing the isolation of highly enriched FOXP3+ cells with all functional and molecular characteristics of natural Treg. Here, we demonstrate that upon in vitro expansion, CpG methylation in a conserved region within the FOXP3 gene locus increased in CD4+CD25+CD127low Treg, correlating with loss of FOXP3 expression and emergence of pro-inflammatory cytokines. Further analysis identified CD45RA,FOXP3+ memory-type Treg as the main source of converting cells, whereas CD45RA+FOXP3+ Treg from the same donors showed no conversion within 3,wk of in vitro expansion. Thus, Treg cell lineage differentiation does not seem to represent a final fate decision, as natural Treg can lose their cell-type-specific characteristics after repetitive TCR stimulation. [source] Expression and function of NKG2D in CD4+ T cells specific for human cytomegalovirusEUROPEAN JOURNAL OF IMMUNOLOGY, Issue 12 2006Andrea Sáez-Borderías Abstract The human NKG2D killer lectin-like receptor (KLR) is coupled by the DAP10 adapter to phosphoinositide 3-kinase (PI3,K) and specifically interacts with different stress-inducible molecules (i.e. MICA, MICB, ULBP) displayed by some tumour and virus-infected cells. This KLR is commonly expressed by human NK cells as well as TCR,,+ and TCR,,+CD8+ T lymphocytes, but it has been also detected in CD4+ T cells from rheumatoid arthritis and cancer patients. In the present study, we analysed NKG2D expression in human cytomegalovirus (HCMV)-specific CD4+ T lymphocytes. In vitro stimulation of peripheral blood mononuclear cells (PBMC) from healthy seropositive individuals with HCMV promoted variable expansion of CD4+NKG2D+ T lymphocytes that coexpressed perforin. NKG2D was detected in CD28, and CD28dull subsets and was not systematically associated with the expression of other NK cell receptors (i.e. KIR, CD94/NKG2 and ILT2). Engagement of NKG2D with specific mAb synergized with TCR-dependent activation of CD4+ T cells, triggering proliferation and cytokine production (i.e. IFN-, and TNF-,). Altogether, the data support the notion that NKG2D functions as a prototypic costimulatory receptor in a subset of HCMV-specific CD4+ T lymphocytes and thus may have a role in the response against infected HLA class II+ cells displaying NKG2D ligands. [source] Expression of the NKG2D ligand UL16 binding protein-1 (ULBP-1) on dendritic cellsEUROPEAN JOURNAL OF IMMUNOLOGY, Issue 1 2006David Schrama Abstract Innate and adaptive immunity have not evolved separately. In this regard, the NKG2D molecule first identified on NK cells and classified as an activating NK cell receptor is also an important receptor for CD8+ T,cells. Functional analyses of human NKG2D and its ligands, i.e. UL16 binding proteins (ULBP) and MHC class I chain-related (MIC), have so far focused on immune cell-target cell situations because of the expression of NKG2D ligands on infected, stressed or transformed cells. Here, however, we address a possible function of NKG2D/ULBP-1 during the initiation of T cell responses. ULBP-1 can be detected on mature dendritic cells both in situ in the T cell areas of lymph nodes as well as in vitro after artificial maturation. FCM analysis further demonstrated that although NKG2D is expressed to some degree on all analyzed T cell subsets from peripheral blood, in vitro stimulation of T cells results in up-regulation of NKG2D on proliferating T cells. Using the sentinel lymph nodes of primary melanoma as a model for induction of defined T cell responses in vivo, we were able to demonstrate the expression of NKG2D on melanoma-associated antigen-specific T cells. Thus, our results suggest a role for NGK2D-ULBP-1 in the induction or reactivation of T cell responses. [source] Anti-tumor MHC class,Ia-unrestricted CD8 T,cell cytotoxicity elicited by the heat shock protein gp96EUROPEAN JOURNAL OF IMMUNOLOGY, Issue 9 2004Ana Goyos Abstract In Xenopus as in mammals, gp96 stimulates MHC-restricted cellular immunity against chaperoned minor histocompatibility (H) antigens (Ag). In adult Xenopus, gp96 also elicits peptide-specific effectors against MHC class,Ia-negative 15/0 tumors. To determine whether gp96 can generate functionally heterogeneous CD8+ effectors (CTL that kill MHC class,Ia+ minor,H-Ag-disparate lymphoblasts and MHC class,Ia, tumor targets), LG-6 isogenetic frogs were immunized with gp96 purified either from MHC-identical but minor,H-Ag-disparate LG-15 normal tissues or from the MHC class,Ia-negative 15/0 tumor line (derived from LG-15 frogs). LG-15 normal liver-derived gp96 did not induce detectable CD8+in vitro killing against 15/0 tumor cells. However, 15/0-derived gp96 did induce killing against both MHC class,Ia+ LG-15 lymphoblasts and the MHC class,Ia, 15/0 tumor, but not against another MHC class,Ia, tumor (B3B7) or against LG-6 lymphoblasts. Tumor killing was better when 15/0 rather than normal LG-15 irradiated stimulators were used, but in vitro stimulation without prior in vivo immunization was ineffective. These data suggest that (1),15/0-derived gp96 chaperones minor,H-Ag shared with normal LG-15 lymphocytes and elicits MHC-restricted CTL, and (2),15/0-derived gp96, but not normal liver-derived gp96, generates CD8+ effectors that kill 15/0 tumor cells in the absence of MHC class,Ia expression. [source] The Toll-like receptor ligand MALP-2 stimulates dendritic cell maturation and modulates proteasome composition and activityEUROPEAN JOURNAL OF IMMUNOLOGY, Issue 3 2004Claudia Link Abstract A 2-kDa synthetic derivative of the macrophage-activating lipopeptide (MALP-2) from Mycoplasma fermentans is a potent inducer of monocytes/macrophages and improves the immunogenicity of antigens co-administered by systemic and mucosal routes. Dendritic cells (DC) are the most potent antigen-presenting cells, which are able to prime naive T cells in vivo. To elucidate the underlying mechanisms of MALP-2 adjuvanticity, we analyzed its activity on bone marrow-derived murine DC. In vitro stimulation of immature murine DC with MALP-2 resulted in the induction of maturation with up-regulated expression of MHC class II, costimulatory (CD80, CD86) and adhesion (CD40, CD54) molecules. MALP-2 also enhances the secretion of cytokines (IL-1,, IL-6 and IL-12), and increases DC stimulatory activity on naive and antigen-specific T cells. Further studies demonstrated that MALP-2 treatment of DC results in a dose-dependent shift from the protein pattern of proteasomes to immunoproteasomes (up-regulation of LMP2, LMP7 and MECL1), which correlates with an increased proteolytic activity. Thus, the adjuvanticity of MALP-2 can be mediated, at least in part, by the stimulation of DC maturation, which in turn leads to an improved antigen presentation. Therefore, MALP-2 is a promising molecule for the development of immune therapeutic or prophylactic interventions. [source] Detrimental role of endogenous nitric oxide in host defence against Sporothrix schenckiiIMMUNOLOGY, Issue 4 2008Karla Simone S. Fernandes Summary We earlier demonstrated that nitric oxide (NO) is a fungicidal molecule against Sporothrix schenckii in vitro. In the present study we used mice deficient in inducible nitric oxide synthase (iNOS,/,) and C57BL/6 wild-type (WT) mice treated with N,-nitro-arginine (Nitro-Arg-treated mice), an NOS inhibitor, both defective in the production of reactive nitrogen intermediates, to investigate the role of endogenous NO during systemic sporotrichosis. When inoculated with yeast cells of S. schenckii, WT mice presented T-cell suppression and high tissue fungal dissemination, succumbing to infection. Furthermore, susceptibility of mice seems to be related to apoptosis and high interleukin-10 and tumour necrosis factor-, production by spleen cells. In addition, fungicidal activity and NO production by interferon-, (IFN-,) and lipopolysaccharide-activated macrophages from WT mice were abolished after fungal infection. Strikingly, iNOS,/, and Nitro-Arg-treated mice presented fungal resistance, controlling fungal load in tissues and restoring T-cell activity, as well as producing high amounts of IFN-, Interestingly, macrophages from these groups of mice presented fungicidal activity after in vitro stimulation with higher doses of IFN-,. Herein, these results suggest that although NO was an essential mediator to the in vitro killing of S. schenckii by macrophages, the activation of NO system in vivo contributes to the immunosuppression and cytokine balance during early phases of infection with S. schenckii. [source] Increased expression of mRNA encoding interleukin (IL)-4 and its splice variant IL-4,2 in cells from contacts of Mycobacterium tuberculosis, in the absence of in vitro stimulationIMMUNOLOGY, Issue 4 2004Helen A. Fletcher Summary Expression of interleukin (IL)-4 is increased in tuberculosis and thought to be detrimental. We show here that in healthy contacts there is increased expression of its naturally occurring antagonist, IL-4delta2 (IL-4,2). We identified contacts by showing that their peripheral blood mononuclear cells (PBMC) released interferon (IFN)-, in response to the Mycobacterium tuberculosis -specific antigen 6 kDa early secretory antigenic target (ESAT-6). Fresh unstimulated PBMC from these contacts contained higher levels of mRNA encoding IL-4,2 (P=0·002) than did cells from ESAT-6 negative donors (noncontacts). These data indicate that contact with M. tuberculosis induces unusual, previously unrecognized, immunological events. We tentatively hypothesize that progression to active disease might depend upon the underlying ratio of IL-4 to IL-4,2. [source] Human autologous mixed lymphocyte reaction as an in vitro model for autoreactivity to apoptotic antigensIMMUNOLOGY, Issue 3 2002Mohammad R. Amel Kashipaz Summary Recent studies have indicated that cells undergoing apoptosis are the source of autoantigens which drive autoimmune responses in systemic lupus erythematosus (SLE). It has been recognized for many years that in vitro stimulation of T cells with irradiated major histocompatibility complex (MHC) class II-bearing autologous cells results in T-cell proliferation with immunological specificity and memory, namely the autologous mixed lymphocyte reaction (AMLR). The nature of the major stimulants in the AMLR is still unclear. We investigated whether apoptotic fragments from irradiated cells act as antigenic stimulators for AMLR or nucleohistone-primed T cells. T-cell proliferation in the primary AMLR was significantly suppressed by the presence of a caspase inhibitor Z-Val-Ala-Asp-CH2F (Z-VAD.fmk), indicating that apoptotic antigens released from irradiated autologous feeder cells act as stimulators of AMLR T cells. This inhibitory effect of Z-VAD was not caused by toxic effects, because the T-cell response to the mitogen phytohaemagglutinin (PHA) was not inhibited by Z-VAD. A nucleohistone preparation was shown to contain antigens that are important in the AMLR, as culture with nucleohistone (but not with thyroglobulin or hen-egg lysozyme) primed T cells to respond with secondary kinetics in a subsequent AMLR that was also suppressed by Z-VAD. Our data provide evidence that the AMLR constitutes a model for the evaluation of cellular and molecular mechanisms that may be relevant to the pathogenesis of SLE and similar autoimmune diseases. [source] Identification of SPARC as a candidate target antigen for immunotherapy of various cancersINTERNATIONAL JOURNAL OF CANCER, Issue 6 2010Mitsuhiro Inoue Abstract To establish efficient anticancer immunotherary, it is important to identify tumor-associated antigens (TAAs) directing the immune system to attack cancer. A genome-wide cDNA microarray analysis identified that secreted protein acidic and rich in cysteine (SPARC) gene is overexpressed in the gastric, pancreatic and colorectal cancer tissues but not in their noncancerous counterparts. This study attempted to identify HLA-A24 (A*2402)-restricted and SPARC-derived CTL epitopes. We previously identified H-2Kd -restricted and SPARC-derived CTL epitope peptides in BALB/c mice, of which H-2Kd -binding peptide motif is comparable with that of HLA-A24 binding peptides. By using these peptides, we tried to induce HLA-A24 (A*2402)-restricted and SPARC-reactive human CTLs and demonstrated an antitumor immune response. The SPARC-A24-1143,151 (DYIGPCKYI) and SPARC-A24-4225,234 (MYIFPVHWQF) peptides-reactive CTLs were successfully induced from peripheral blood mononuclear cells by in vitro stimulation with these two peptides in HLA-A24 (A*2402) positive healthy donors and cancer patients, and these CTLs exhibited cytotoxicity specific to cancer cells expressing both SPARC and HLA-A24 (A*2402). Furthermore, the adoptive transfer of the SPARC-specific CTLs could inhibit the tumor growth in nonobese diabetic/severe combined immunodeficient mice bearing human cancer cells expressing both HLA-A24 (A*2402) and SPARC. These findings suggest that SPARC is a potentially useful target candidate for cancer immunotherapy. [source] Immunogenicity and effect of a virosomal influenza vaccine on viral replication and T-cell activation in HIV-infected children receiving highly active antiretroviral therapy,JOURNAL OF MEDICAL VIROLOGY, Issue 4 2006Elisabetta Tanzi Abstract In order to evaluate the immunogenicity and the effect of a virosomal influenza vaccine on viral replication and T-cell activation in HIV-infected children receiving highly active antiretroviral therapy (HAART), 29 children infected with HIV-1 vertically (19 primed with a previous influenza vaccination and 10 who were not been immunized against influenza) were immunized with an intramuscular virosome-adjuvanted influenza vaccine. According to the European Agency for Evaluation of Medical Products (EMEA) criteria, the immunogenicity of the vaccine was adequate against all three influenza strains (A H1N1, A H3N2, and B) in the primed children, and against A H1N1 and A H3N2 in the unprimed children. After in vitro stimulation with vaccine antigens, the IFN-, levels in the peripheral blood mononuclear cells cultures increased significantly from a baseline level of 103.0,±,229.8 pg/ml to a 30-day level of 390.7,±,606.3 pg/ml (P,<,0.05), with concentrations significantly higher (P,<,0.05) in the primed children than in the unprimed children. No increase in plasma HIV-1 RNA or HIV-1 proviral DNA was observed in either subgroup, and the immunophenotype analyses demonstrated that the CD4+ cell counts and percentages, the CD4/CD8 ratio and activated lymphocytes remained stable in either group from baseline to 1 month after each vaccine dose. This study showed that the virosomal influenza vaccine does seem to be immunogenic in the majority of HIV-infected children receiving HAART and does not induce viral replication or T-cell activation. Given the possible influenza-related complications in children infected with HIV, these results support the use of this influenza vaccine in such patients. J. Med. Virol. 78:440,445, 2006. © 2006 Wiley-Liss, Inc. [source] Ethanol Exposure Impairs LPS-Induced Pulmonary LIX Expression: Alveolar Epithelial Cell Dysfunction as a Consequence of Acute IntoxicationALCOHOLISM, Issue 2 2009James E. Walker Jr Background:, Alcohol intoxication impairs innate immune responses to bacterial pneumonia, including neutrophil influx. Lipopolysaccharide (LPS)-induced chemokine (LIX or CXCL5) is a recently described chemokine produced by type-II alveolar epithelial (AE2) cells which facilitates neutrophil recruitment. The effect of acute alcohol intoxication on AE2 cell expression of LIX is unknown. Methods:, C57BL/6 mice were given an intraperitoneal (i.p.) injection of ethanol (4 g/kg) or saline 30 minutes prior to intratracheal (i.t.) injection with 10 ,g Escherichia coli LPS. In vitro stimulation of primary AE2 cells or murine AE2 cell line MLE-12 was performed with LPS and tumor necrosis factor-alpha (TNF-,). Results:, LIX protein is readily detectable in the lung but not in plasma following LPS administration, demonstrating "compartmentalization" of this chemokine during pulmonary challenge. In contrast to the CXC chemokines keratinocyte-derived chemokine and macrophage inflammatory protein-2, which are abundantly expressed in both lung tissue and alveolar macrophages, LIX expression is largely confined to the lung parenchyma. Compared to controls, intoxicated animals show a decrease in LIX and neutrophil number in bronchoalveolar lavage fluid following LPS challenge. Ethanol inhibits LIX at the transcriptional level. In vitro studies show that LPS and TNF-, are synergistic in inducing LIX by either primary AE2 or MLE-12 cells. Acute ethanol exposure potently and dose-dependently inhibits LIX expression by AE2 cells. Activation of nuclear factor-,B is critical to LIX expression in MLE-12 cells, and acute ethanol treatment interferes with early activation of this pathway as evidenced by impairing phosphorylation of p65 (RelA). Inhibition of p38 mitogen-activated protein kinase signaling, but not ERK1/2 activity, in MLE-12 cells by acute alcohol is likely an important cause of decreased LIX expression during challenge. Conclusions:, These data demonstrate direct suppression of AE2 cell innate immune function by ethanol and add to our understanding of the mechanisms by which acute intoxication impairs the lung's response to microbial challenge. [source] Dissection of a functional interaction between the DNA translocase, FtsK, and the XerD recombinaseMOLECULAR MICROBIOLOGY, Issue 6 2006James Yates Summary Successful bacterial circular chromosome segregation requires that any dimeric chromosomes, which arise by crossing over during homologous recombination, are converted to monomers. Resolution of dimers to monomers requires the action of the XerCD site-specific recombinase at dif in the chromosome replication terminus region. This reaction requires the DNA translocase, FtsKC, which activates dimer resolution by catalysing an ATP hydrolysis-dependent switch in the catalytic state of the nucleoprotein recombination complex. We show that a 62-amino-acid fragment of FtsKC interacts directly with the XerD C-terminus in order to stimulate the cleavage by XerD of BSN, a dif-DNA suicide substrate containing a nick in the ,bottom' strand. The resulting recombinase,DNA covalent complex can undergo strand exchange with intact duplex dif in the absence of ATP. FtsKC -mediated stimulation of BSN cleavage by XerD requires synaptic complex formation. Mutational impairment of the XerD,FtsKC interaction leads to reduction in the in vitro stimulation of BSN cleavage by XerD and a concomitant deficiency in the resolution of chromosomal dimers at dif in vivo, although other XerD functions are not affected. [source] Activation by malaria antigens renders mononuclear cells susceptible to HIV infection and re-activates replication of endogenous HIV in cells from HIV-infected adultsPARASITE IMMUNOLOGY, Issue 5 2004K. Froebel SUMMARY We have tested the hypothesis that activation of T cells by exposure to malaria antigens facilitates both de novo HIV infection and viral reactivation and replication. PBMC from malaria-naďve HIV-uninfected European donors could be productively infected with HIV following in vitro stimulation with a lysate of Plasmodium falciparum schizonts and PBMC from malaria-naďve and malaria-exposed (semi-immune) HIV-positive adults were induced to produce higher levels of virus after stimulation with the same malaria extract. These findings suggest that effective malaria control measures might con-tribute to reducing the spread of HIV and extending the life span of HIV-infected individuals living in malaria endemic areas. [source] ORIGINAL ARTICLE: Women with Pre-Eclampsia Have an Altered NKG2A and NKG2C Receptor Expression on Peripheral Blood Natural Killer CellsAMERICAN JOURNAL OF REPRODUCTIVE IMMUNOLOGY, Issue 3 2009Nora Bachmayer Problem, Preeclampsia, a pregnancy disorder, is associated with exaggerated inflammation and increased serum monokines. Uterine natural killer (NK) cells are implicated in preeclampsia pathology, but little is known regarding peripheral NK cells in the disease. Method of Study, We examined blood NK cells at delivery in women with preeclampsia, in healthy pregnant women and in healthy non-pregnant blood donors as a reference. Results, Although the percentages of both NKG2A- and NKG2C-positive NK cells were normal in preeclamptic women, the levels of NKG2A and NKG2C on NK cells were significantly up-regulated in these women. In vitro stimulation of PBMCs from healthy pregnant women and blood donors with monokines resulted in increased percentage of NKG2A+ NK cells and increased NKG2A levels, while levels of NKG2C were decreased. Conclusions, Our results suggest that the peripheral NK-cell pool is skewed in preeclampsia and possibly under the influence of monokines like interleukin (IL)-15 and IL-12. [source] CD4+CD25+FOXP3+ Regulatory T Cells Increase De Novo in Kidney Transplant Patients After Immunodepletion with Campath-1HAMERICAN JOURNAL OF TRANSPLANTATION, Issue 4 2008D. D. Bloom Campath-1H (Alemtuzumab) is an effective immunodepletion agent used in renal transplantation. To evaluate its influence on T lymphocytes during repletion, we analyzed peripheral blood from Campath-1H-treated renal allograft recipients for the presence of FOXP3+ regulatory T (Treg) cells. Flow cytometry demonstrated that CD4+CD25+FOXP3+ lymphocytes increased significantly within the CD4+ T-cell population, skewing Treg/Teff (T effector) ratios for up to several years. In contrast, Treg levels in patients treated with anti-CD25 (Basiliximab) and maintained on CsA demonstrated a sustained decrease. The increase in Tregs in Campath-1H treated patients developed independent of maintenance immunosuppression. Importantly, the increase in Tregs was not fully explained by their homeostatic proliferation, increased thymic output, or Treg sparing, suggesting de novo generation/expansion. Consistent with this, in vitro stimulation of PBMCs with Campath-1H, with or without anti-CD3, activation led to an increase in CD4+CD25+FOXP3+ cells that had suppressive capabilities. Together, these data suggest that Campath-1H promotes an increase in peripheral Tregs and may act as an intrinsic generator of Tregs in vivo. [source] Caspase 1,independent activation of interleukin-1, in neutrophil-predominant inflammationARTHRITIS & RHEUMATISM, Issue 12 2009Monica Guma Objective Interleukin-1, (IL-1,) is a key cytokine linked to the pathogenesis of acute arthritis. Caspase 1, neutrophil elastase, and chymase all process proIL-1, to its biologically active form. This study was undertaken to examine the potential contributions of each of these proteases in experimental models of inflammatory arthritis. Methods Caspase 1,deficient (Casp1,/,) and wild-type (WT) mice were tested for their response to arthritogenic K/BxN serum transfer for induction of arthritis or injection of monosodium urate monohydrate (MSU) crystals for induction of peritonitis. All mice were prophylactically treated with inhibitors of neutrophil elastase or chymase. Arthritic paws were tested for the presence of IL-1, protein by enzyme-linked immunosorbent assay and Western blotting. Neutrophils and mast cells from WT and mutant mice were tested for their ability to secrete IL-1, after in vitro stimulation, in the presence of protease inhibitors. Results Casp1,/, and WT mice developed paw swelling to the same extent in the K/BxN serum transfer,induced arthritis model. MSU crystal injection into Casp1,/, mice also resulted in neutrophil influx and production of measurable peritoneal IL-1, protein. Both of these responses were attenuated with neutrophil elastase inhibitors. K/BxN serum transfer,induced arthritis was also reduced by treatment with a chymase inhibitor. Casp1,/, neutrophils and mast cells, when exposed to MSU crystals, secreted similar amounts of IL-1, protein upon in vitro stimulation with lipopolysaccharide, albeit at lower levels than that secreted by WT cells. Elastase and chymase inhibitors reduced the amount of IL-1, released by these cells. Conclusion The production of IL-1, by neutrophils and mast cells is not exclusively dependent on caspase 1, and other proteases can compensate for the loss of caspase 1 in vivo. These pathways might therefore compromise the caspase 1,targeted therapies in neutrophil-predominant arthritis. [source] Different amplifying mechanisms of interleukin-17 and interferon-, in Fc, receptor,mediated cartilage destruction in murine immune complex,mediated arthritisARTHRITIS & RHEUMATISM, Issue 2 2009Lilyanne C. Grevers Objective Previously, we reported that interferon-, (IFN,) aggravates cartilage destruction in immune complex (IC),mediated arthritis via up-regulation of activating Fc, receptors (Fc,R). Recently, we found that interleukin-17 (IL-17) also aggravates cartilage destruction in arthritis models in which ICs are involved, but the underlying mechanism remains unknown. This study was undertaken to determine the role of IL-17 in Fc,R-mediated cartilage destruction in IC-mediated arthritis and to compare its effect with that of IFN,. Methods IC-mediated arthritis was passively induced in ,-chain,/, mice, which lack functional activating Fc,R, and in wild-type controls. AdIL-17 or a control vector was injected into the knee joints 1 day prior to induction of IC-mediated arthritis. Knee joints were isolated for histologic analysis, and synovium samples were obtained for reverse transcriptase,polymerase chain reaction (RT-PCR). Macrophage (RAW 264.7) cell lines and polymorphonuclear cell (PMN; 32Dcl3) lines were stimulated with IFN, or IL-17 for analysis of Fc,R expression using RT-PCR and fluorescence-activated cell sorting. Results IL-17 overexpression prior to induction of IC-mediated arthritis significantly aggravated cartilage destruction and inflammation, characterized by a massive influx of PMNs, which adhered to the cartilage surface. Although IL-17 overexpression increased Fc,R messenger RNA levels in the synovium, in vitro stimulation of macrophages and PMNs revealed that, in contrast to IFN,, IL-17 did not directly regulate Fc,R expression. Despite similar inflammation in AdIL-17,enhanced IC-mediated arthritis in ,-chain,/, mice and wild-type controls, severe cartilage destruction and PMN adherence were completely absent in ,-chain,/, mice. Conclusion Our findings indicate that IL-17,mediated aggravation of cartilage destruction in IC-mediated arthritis is Fc,R dependent. However, in contrast to IFN,, which directly up-regulates Fc,R expression on macrophages and PMNs, IL-17 enhances cartilage destruction by increasing the local amount of Fc,R-bearing neutrophils. [source] CTLA-4 (CD152) controls homeostasis and suppressive capacity of regulatory T cells in miceARTHRITIS & RHEUMATISM, Issue 1 2009Paula Kolar Objective CD4+CD25+ regulatory T cells (known as Treg cells) suppress unwanted and autoreactive T cell responses. Treg cells express the costimulatory molecule CTLA-4 intracellularly, but the mechanisms by which Treg cells exploit CTLA-4 signaling remain unclear. The present study was undertaken to investigate the role of CTLA-4 in controlling the homeostasis and suppressive function of Treg cells. Methods Murine Treg cells were analyzed by flow cytometry for coexpression of CTLA-4 and typical Treg cell,expressed molecules, and the influence of CTLA-4 on T cell proliferation, suppression, and apoptosis was investigated by in vitro assays. To analyze the importance of CTLA-4 in Treg cell,mediated suppression in vivo, wild-type Treg cells were transferred into CTLA-4,deficient mice displaying lymphoproliferation, and survival was monitored over time. Results A strong correlation between expression of forkhead box P3 and ex vivo expression of CTLA-4 in Treg cells was observed. Inhibition of CTLA-4 signaling in Treg cells during in vitro stimulation increased cell cycling and led to enhanced activation-induced cell death (AICD), which was mediated by CD95/CD95 ligand,induced activation of caspases. Blockade of CTLA-4 signaling resulted in impairment of the suppressive capacity of Treg cells. Despite these effects, high amounts of Treg cells persisted in CTLA-4,deficient mice. Results of transfer experiments in CTLA-4,deficient mice showed that the mice had a significantly prolonged lifespan when CTLA-4,competent Treg cells were injected. Conclusion Expression of CTLA-4 on Treg cells serves to control T cell proliferation, to confer resistance against AICD, and to maintain the suppressive function of Treg cells. [source] Macrophage migration inhibitory factor promoter polymorphisms and the clinical expression of sclerodermaARTHRITIS & RHEUMATISM, Issue 11 2006Sou-Pan Wu Objective To investigate the potential association between functional polymorphisms in the gene for the innate mediator, macrophage migration inhibitory factor (MIF), and the clinical expression of systemic sclerosis (SSc). Methods Genomic DNA samples and clinical data were collected from the Scleroderma Family Registry and DNA Repository at the University of Texas Health Science Center at Houston. A total of 740 subjects were studied; 203 of them had diffuse cutaneous SSc (dcSSc), 283 had limited cutaneous SSc (lcSSc), and the remaining 254 healthy subjects served as controls. Association analyses were performed on the whole data set and on patient and sex subsets. Significant relationships were determined between clinical variables and MIF polymorphisms for each disease subtype in the studied groups. Results The frequency of the ,173*C MIF allele, which was previously reported to be associated with high production of MIF, was lower in the lcSSc group (12.6%) than in the dcSSc (19.2%) or control (18.5%) groups (P = 0.010 and P = 0.011, respectively). Haplotype analysis for 2 closely linked polymorphisms in the MIF promoter showed that in white subjects with lcSSc or dcSSc, the lcSSc population had a significantly lower representation of the high-expression MIF haplotype defined by ,173*C and ,794 with 7 CATT repeats (C7) (P = 0.015, odds ratio 1.94 [95% confidence interval 1.14,3.32]). Fibroblasts encoding the C7 MIF haplotype were observed to produce more MIF upon in vitro stimulation than those with a non-C7 haplotype. Conclusion Functional promoter polymorphisms in the MIF gene affect the clinical presentation of SSc. The proinflammatory haplotype defined by C7 is underrepresented in patients with lcSSc. [source] Abnormal differentiation of memory T cells in systemic lupus erythematosusARTHRITIS & RHEUMATISM, Issue 7 2006Ruth D. Fritsch Objective The chemokine receptor CCR7 and the tumor necrosis factor receptor family member CD27 define 3 distinct, progressively more differentiated maturational stages of CD4 memory subpopulations in healthy individuals: the CCR7+,CD27+, the CCR7,, CD27+, and the CCR7,,CD27, populations. The goal of this study was to examine maturational disturbances in CD4 T cell differentiation in systemic lupus erythematosus (SLE), using these phenotypic markers. Methods Phenotypic analysis by flow cytometry, in vitro stimulation experiments, telomere length measurement, and determination of inducible telomerase were carried out. Results In SLE patients, significant increases of CCR7,,CD27, and CCR7,,CD27+ and a reduction of CCR7+,CD27+ CD4 memory T cells were found. In vitro stimulation of SLE T cells showed a stepwise differentiation from naive to CCR7+,CD27+ to CCR7,,CD27+ to CCR7,,CD27,; telomere length and inducible telomerase decreased in these subsets in the same progressive sequence. The in vitro proliferative response of these populations progressively declined as their susceptibility to apoptosis increased. Interestingly, a significant reduction in inducible telomerase was noted in SLE naive and CCR7+,CD27+ CD4+ memory T cells. Additionally, SLE CCR7,,CD27+ and CCR7,, CD27, CD4 memory T cells proliferated poorly in response to in vitro stimulation and underwent significantly more apoptosis than their normal counterparts. Finally, expression of CXCR4 was significantly reduced in all SLE subsets compared with normal. Conclusion Together these data indicate an increased degree of in vivo T cell stimulation in SLE, resulting in the accumulation of terminally differentiated memory T cells with a decreased proliferative capacity and an increased tendency to undergo apoptosis upon stimulation. [source] Down-regulation of the nonspecific and antigen-specific T cell cytokine response in ankylosing spondylitis during treatment with infliximabARTHRITIS & RHEUMATISM, Issue 3 2003Jianxiang Zou Objective Treatment of active ankylosing spondylitis (AS) with the monoclonal tumor necrosis factor , (TNF,) antibody infliximab is highly clinically effective. This study was undertaken to investigate the precise mechanism of action of anti-TNF, treatment in AS. Methods Cytokine expression of CD4+ and CD8+ T cells was investigated before and 6 and 12 weeks after the start of treatment in 10 patients treated with infliximab, and before and after 6 weeks of treatment and 6 weeks after placebo was switched to infliximab in 10 patients treated initially with placebo. Peripheral blood mononuclear cells (PBMCs) were stimulated for 6 hours either nonspecifically with phorbol myristate acetate (PMA)/ionomycin or antigen specifically with a pool of 46 overlapping 18-mer peptides derived from the G1 domain of aggrecan. Cells were stained for T cell surface markers CD4 and CD8 and for the intracellular cytokines interferon-, (IFN,), TNF,, interleukin-4 (IL-4), and IL-10. Positive cells were quantified by flow cytometry. For monocyte-derived cytokines, PBMCs were stimulated with lipopolysaccharide (LPS) for 18 hours and TNF, and IL-10 in the supernatant were measured by enzyme-linked immunosorbent assay. Results Compared with baseline, infliximab treatment induced a significant decrease at 12 weeks in the number of CD4+ and CD8+ T cells that were positive for IFN, and TNF, upon PMA/ionomycin stimulation (P = 0.005). A significant reduction had already begun to occur at 6 weeks. No change in the percent IFN, or TNF, positivity among CD4+ and CD8+ subpopulations was observed after 6 weeks in patients treated with placebo. However, when these patients began infliximab treatment after 6 weeks of receiving placebo, there was a similar significant decrease in IFN, and TNF, production by CD4+ and CD8+ T cells (P < 0.05). Furthermore, infliximab treatment induced a significant reduction in the number of IFN,+ and TNF,+ CD8+ T cells (P = 0.005 at week 6 and week 12) after antigen-specific in vitro stimulation with G1-derived peptides. Between-group analysis showed that the change in the expression of IFN, and TNF, in both CD4+ and CD8+ T cells was significantly different between the infliximab and placebo groups (P = 0.001 for all variables). There was no change in the number of IL-10+ or IL-4+ T cells during treatment. No significant change in the production of TNF, and IL-10 upon in vitro stimulation of PBMCs with LPS was detectable during infliximab treatment. Conclusion Infliximab down-regulates both IFN, and TNF, secreted by T cells but does not induce a change in cytokines produced by monocytes during 3 months of treatment. This is likely to be a relevant mechanism for the clinical efficacy of this therapy. [source] Local inflammatory response in choriodecidua induced by Ureaplasma urealyticumBJOG : AN INTERNATIONAL JOURNAL OF OBSTETRICS & GYNAECOLOGY, Issue 11 2007R Aaltonen Ureaplasma urealyticum is the bacterial species most often connected with preterm birth, although it often colonises the amniotic fluid without any adverse effects. The induction of preterm labour seems to depend on whether the bacteria produce an inflammatory reaction. In vitro stimulation of choriodecidual tissue with high amounts of U.urealyticum or with lipopolysaccharide induced a qualitatively similar inflammatory response detected by the production of tumour necrosis factor alpha, followed by secretion of anti-inflammatory cytokine interleukin-10 and of prostaglandin E2. Lower quantities of bacteria failed to induce any response. [source] Mitoxantrone treatment in multiple sclerosis induces TH2-type cytokinesACTA NEUROLOGICA SCANDINAVICA, Issue 4 2010A. Vogelgesang Vogelgesang A, Rosenberg S, Skrzipek S, Bröker BM, Dressel A. Mitoxantrone treatment in multiple sclerosis induces TH2-type cytokines. Acta Neurol Scand: 2010: 122: 237,243. © 2009 The Authors Journal compilation © 2009 Blackwell Munksgaard. Objectives,,, Mitoxantrone is a cytotoxic drug with immune modulatory properties used in the treatment of progressive forms of multiple sclerosis (MS). We explored the effect of mitoxantrone treatment in MS patients on cytokine patterns induced in peripheral blood mononuclear cells (PBMC) and T-cell subsets ex vivo. Materials and methods,,, Blood was obtained before mitoxantrone infusion and 6, 12 and 18 days thereafter. Proliferation and prototypic TH1-, TH17- and TH2-type cytokines were determined following in vitro stimulation of PBMC, CD4+ and CD8+ T cells. In addition, a patient cohort receiving its first mitoxantrone treatment was cross-sectionally compared with a cohort of patients with more than 1 year of treatment. Results,,, Mitoxantrone treatment increased the ex vivo production of the TH2 cytokines interleukin-4 (IL-4; P < 0.05) and IL-5 (P < 0.001) in phytohemagglutinin-stimulated CD4+ T cells within 18 days of treatment. The cross-sectional study revealed that long-term treatment with mitoxantrone increased the inducibility of IL-4 and IL-5 secretion by PBMCs and CD4+ T cells even further. No significant changes were observed for interferon-,, tumour necrosis factor-,, IL-17 and IL-10. Mitoxantrone did not alter the proliferative capacity of ex vivo -stimulated T cells. Conclusion,,, Mitoxantrone treatment in MS enhances the inducibility of TH2-type cytokines, which may contribute to its beneficial effects in MS. [source] Analysis of CD8 T-cell response by IFN, ELISPOT and H-2Ld/ pRL1a tetramer assays in pRL1a multiple antigen peptide-immunized and RL male 1-bearing BALB/ c and (BALB/c×C57BL/6) F1 miceCANCER SCIENCE, Issue 3 2004Itsuro Takada We previously identified an H-2Ld -binding peptide pRL1a (IPGLPLSL) on RL male 1 that is predominantly recognized by cytotoxic T-lymphocytes (CTLs). MAP is a multibranched lysine core with antigenic peptides. Immunization of BALB/c mice with pRL1a MAP effectively induced pRL1a CTLs. Here, we demonstrate the presence of pRL1a-recognizing CD8+ T-cells in pRL1a MAP-immunized and RL male 1-bearing BALB/c and (BALB/ cxC57BL/6)F1 mice by using IFN, ELISPOT and H-2Ld/pRL1a tetramer assays. A few IFN, ELISPOTs and no tetramer-positive cells were detected ex vivo in spleen cells from BALB/c mice immunized with pRL1a MAP. After a single in vitro stimulation with RL male 1, 432 and 741 IFN, ELISPOTs/105 cells were detected and tetramer-positive CD8+ T-cells occurred at relative frequencies of 5.7% and 30.8% in splenic CD8+ T-cells from mice that had been doubly and triply immunized, respectively, against pRL1a MAP. Tetramer-positive cells displayed two distinct cell populations, CD62Llow and CD62Lhigh. Secondary in vitro stimulation expanded CD62Lhigh cells more efficiently than CD62Llow cells. Furthermore, a higher frequency of IFN,-producing and tetramer-positive CD8+ T-cells was detected ex vivo in RL male 1-bearing semi-allogeneic (BALB/cxC57BL/6)F1 than in BALB/c mice on day 14 after tumor inoculation. [source] Selective expansion of CD16highCCR2, subpopulation of circulating monocytes with preferential production of haem oxygenase (HO)-1 in response to acute inflammationCLINICAL & EXPERIMENTAL IMMUNOLOGY, Issue 3 2005K. Mizuno Summary Monocytes are composed of two distinct subpopulations in the peripheral blood as determined by their surface antigen expressions, profiles of cytokine production and functional roles played in vivo. We attempted to delineate the unique functional roles played by a minor CD16highCCR2, subpopulation of circulating monocytes. They produced significant levels of interleukin (IL)-6 and tumour necrosis factor (TNF)-,, but very low levels of IL-10 upon in vitro stimulation. Characteristic profiles of cytokine production were confirmed by stimulating purified subpopulations of monocytes after cell sorting. It was noteworthy that freshly isolated CD16highCCR2, monocyte subpopulations produced significant levels of haem oxygenase (HO)-1, whereas the major CD16lowCCR2+ subpopulation produced little. These results were contrary to the generally accepted notion that the CD16highCCR2, monocyte subpopulation plays a predominantly proinflammatory role in vivo. The CD16highCCR2, subpopulation increased in Kawasaki disease and influenza virus infection. In accord with this, HO-1 mRNA expression by mononuclear cells was significantly increased in these illnesses. These results indicate that CD16highCCR2, subpopulations are of a distinct lineage from CD16lowCCR2+ monocytes. More importantly, they may represent a monocyte subpopulation with a unique functional role to regulate inflammation by producing HO-1 in steady state in vivo. [source] Resistance/susceptibility to Echinococcus multilocularis infection and cytokine profile in humans.CLINICAL & EXPERIMENTAL IMMUNOLOGY, Issue 3 2000Differences have been shown between HLA characteristics of patients with different courses of alveolar echinococcosis (AE). Notably the HLA B8, DR3, DQ2 haplotype was associated with more severe forms of this granulomatous parasitic disease. We compared IL-10, IL-5, interferon-gamma (IFN- ,) and tumour necrosis factor (TNF) secretion by peripheral blood mononuclear cells (PBMC) isolated from eight HLA-DR3+, DQ2+, B8+ AE patients and from 10 HLA-DR3,, DQ2,, B8, patients after non-specific mitogenic and specific Echinococcus multilocularis antigenic in vitro stimulation. PBMC from seven HLA-DR3+, DQ2+, B8+ healthy subjects and nine HLA-DR3,, DQ2,, B8, subjects were also studied as controls. PBMC from AE patients with HLA DR3+, DQ2+ haplotype secreted higher levels of IL-10 without any stimulation and after specific antigenic stimulation than did patients without this haplotype. Higher levels of IL-5 and IFN- , were also produced by these patients' PBMC after stimulation with non-purified parasitic antigenic preparations; however, the specific alkaline phosphatase antigen extracted from E. multilocularis induced only Th2-type cytokine secretion. A spontaneous secretion of TNF by HLA DR3+, DQ2+ B8+ AE patients was also found. These results suggest that HLA characteristics of the host can influence immune-mediated mechanisms, and thus the course of AE in humans; specific antigenic components of E. multilocularis could contribute to the preferential Th2-type cytokine production favoured by the genetic background of the host. [source] The kinetics of CD154 (CD40L) expression in peripheral blood mononuclear cells of healthy subjects in liver allograft recipients and X-linked hyper-IgM syndromeCLINICAL TRANSPLANTATION, Issue 6 2000A Bartlett The costimulatory pathways play a key role in T cell activation during allograft rejection (AR). Inhibition of the T cell costimulatory molecule CD154 (CD40 ligand) has been effective in producing long-term allograft survival in rodents and non-human primates. The role of the CD40-CD154 pathway in human orthotopic liver transplantation (OLT) has not been examined. Aim: To describe the patterns of CD154, CD69 and CD152 (CTLA4) expression in OLT recipients and to determine their temporal relationship to AR. Methods: Peripheral blood mononuclear cells (PBMCs) were isolated from 15 OLT allograft recipients just prior to and for seven consecutive days postoperatively. Gene and protein expression of CD154, CD69 and CD154 were examined by reverse transcription-polymerase chain reaction (RT-PCR) and flow cytometry (FC), respectively. Results: FC failed to demonstrate an up-regulation of CD154 and CD152 protein expression during the first postoperative week. Intracellular FC did not increase the sensitivity. There was an increased level of CD3+CD8+ T cells expressing CD69 at the time of rejection compared to that on day 0. RT-PCR demonstrated a sporadic expression of CD154 and CD69 mRNA, with no correlation to episodes of acute cellular rejection. In vitro stimulation of PBMCs revealed an impaired up-regulation of CD154 in patients receiving conventional immunosuppression compared to healthy controls. The assays were validated using positive and negative controls, including a family with X-linked hyper-IgM syndrome. Conclusion: We found no evidence of spontaneous CD154 gene or protein expression in PBMCs associated with acute rejection episodes following OLT. Immunosuppression resulted in impaired responses to ex vivo stimulation. Lymphocyte costimulatory pathways play a critical role in mediating acute allograft rejection. However, we found no evidence of spontaneous CD154 gene or protein expression in PBMCs associated with acute rejection episodes following OLT. Furthermore, stimulation in vitro resulted in less up-regulation of CD154 than for healthy controls. [source] | |||||||||||||||||||||||||