bluuebunny/crossref_metadata_2025_split huggingface dataset:
Modulation of immune dysfunction during murine leukaemia retrovirus infection of old mice by dehyroepiandrosterone sulphate (DHEAS)
Authors: ARAGHI‐NIKNAM M. , LIANG B. , ZHANG Z. , ARDESTANI S. K. , WATSON R. R. 
Published: October 2004

SUMMARYAgeing, leukaemia and acquired immune deficiency syndrome (AIDS) are conditions with dysregulated cytokine production. As dehydroepiandrosterone sulphate (DHEAS) restored normal cytokine production in old mice its effects on retrovirally infected old mice were investigated. Retrovirus infection and ageing‐induced immune dysfunction. Murine retrovirus‐infected old C57BL/6 female mice consumed 0·22 or 0·44 μg of DHEAS/mouse/day beginning 2 weeks postinfection for 10 weeks. DHEAS largely prevented the retrovirus‐induced reduction in T‐cell and B‐cell mitogenesis. DHEAS supplement prevented loss of cytokines [interleukin‐2 (IL‐2) and interferon‐γ] secretion by mitogen‐stimulated splenocytes representing T helper 1 (Th1) cell phenotypes. It also suppressed the retrovirus‐induced, excessive production of cytokines (IL‐6 and IL‐10) by Th2 cells. The highest dose of DHEAS reduced IL‐6 production by splenocytes from uninfected old mice by 75% while increasing their IL‐2 secretion by nearly 50%. Thus immune dysfunction induced by ageing, even when exacerbated by murine retrovirus infection, was largely prevented by DHEAS.
Involvement of Stat3 in interleukin‐6‐induced IgM production in a human B‐cell line
Authors: FARIS M. , KOKOT N. , STAHL N. , NEL A. E. 
Published: October 2004

SUMMARYInterleukin‐6 (IL‐6) is an important B‐cell growth and differentiation factor. IL‐6 treatment of the human lymphoblastoid cell line, SKW6.4, leads to increased IgM production. We have previously shown that IL‐6 induces activation of JAK1 and JAK2 in human B cell lines. A chimeric IL‐6 receptor, comprised of the intracellular tail of the IL‐6 receptor subunit gp130 fused to the extracellular domain of the epidermal growth factor (EGF) receptor, was stably transfected into SKW6.4 cells. EGF treatment induced IgM production in cells transfected with an intact gp130 cytoplasmic tail, but not in untransfected cells or cells transfected with a cytoplasmic tail lacking all four signal transducers and activators of transcription (Stat) binding sites. Moreover, EGF treatment induced Stat3 phosphorylation in cells transfected with the intact chimeric EGF–gp130 receptor along with induction of DNA‐mobility shift of a classical interferon‐γ‐activated site. To define further the relation between Stat3 activation and enhanced IgM production, we determined the effect of chimeric gp130 on the transcriptional activation of a genetic element linked to immunoglobulin production, namely the immunoglobulin heavy chain enhancer (IgH‐enhancer). Parental as well as transfected SKW6.4 cells were transiently transfected with an IgH‐enhancer–luciferase construct. The transcriptional activity of the IgH–luciferase construct was induced upon ligation of the full‐length chimeric receptor but not by truncated gp130 receptors. Moreover, the gp130‐induced activity of this reporter gene was abrogated by Stat3EE, a mutant Stat3 incapable of binding DNA. These results indicate that IL‐6‐induced B‐cell differentiation, as measured by IgM production, may be controlled by Stat3 proteins.
Tumour necrosis factor‐α up‐regulates decay‐accelerating factor gene expression in human intestinal epithelial cells
Authors: ANDOH A. , FUJIYAMA Y. , SUMIYOSHI K. , SAKUMOTO H. , OKABE H. , BAMBA T. 
Published: October 2004

SUMMARYThe increased expression of decay‐accelerating factor (DAF) has been detected in intestinal epithelial cells at the inflamed mucosa. In this study, we examined the effects of tumour necrosis factor (TNF)‐α on DAF expression in three intestinal epithelial cell lines. DAF mRNA expression was evaluated by Northern blot analysis, and DAF protein expression was analysed by biotin labelling and immunoprecipitation. TNF‐α induced a marked increase in DAF mRNA and protein expression in HT‐29, T84 and Caco‐2 cells. In HT‐29 cells, the effects of TNF‐a on DAF mRNA accumulation were observed in a dose‐dependent manner; DAF mRNA accumulation reached a maximum at 3–6 hr, and then gradually decreased. These effects of TNF‐α required de novo protein synthesis. Messenger RNA stability studies suggested that TNF‐α partially regulated DAF gene expression by a posttranscriptional mechanism. Moreover, the combination of TNF‐α and interleukin (IL)‐4 induced an additive increase in DAF mRNA accumulation in HT‐29 and T84 cells. In human intestinal epithelial cells, TNF‐α acts as a potent inducer of DAF mRNA expression, indicating an important role for TNF‐α in the regulation of DAF expression at the inflamed mucosa.
Flexibility in T‐cell receptor ligand repertoires depends on MHC and T‐cell receptor clonotype
Authors: GELUK A. , VAN MEIJGAARDEN K. E. , OTTENHOFF T. H. M. 
Published: October 2004

SUMMARYT‐cell receptors (TCR) recognize peptides complexed to self‐major histocompatibility complex (MHC) molecules. Recognition of peptide/MHC ligands by the TCR is highly peptide specific. However, certain TCRs can also recognize sequence‐related and ‐unrelated (‘mimicry’) epitopes presented by homologous MHC molecules. Using two human, human leucocyte antigen‐DR1 (HLA‐DR1)‐restricted T‐cell clones specific for HA p307–319, we identified several diverse combinations of peptide‐MHC complexes that are functionally equivalent in their ability to trigger T‐cell stimulation. These findings demonstrate that a single TCR can productively interact with different peptides complexed to self‐ as well as non‐self‐MHC molecules. This extended reactivity is human leucocyte antigen (HLA) allele and TCR clonotype dependent, as the peptide repertoire recognized depends on the presenting HLA‐DR molecule and varies among different TCRs that both recognize the HA p307–319/DR1 complex. Importantly, certain peptide analogues can completely change the HLA‐restriction pattern of the TCR: T‐cell recognition of the wild‐type peptide that was absent in the context of a non‐self HLA‐DR molecule, was restored by complementing substitutions in altered peptide ligands, that could not be presented by the original restriction element. This mechanism may play an important role in allorecognition.
The antigen receptor complex on cord B lymphocytes
Authors: MACARDLE P. J. , WEEDON H. , FUSCO M. , NOBBS S. , RIDINGS J. , FLEGO L. , ROBERTON D. M. , ZOLA H. 
Published: October 2004

SUMMARYThe neonatal immune system responds to a restricted range of antigens, producing largely IgM antibody of low affinity. Comparison of the components of the B‐cell antigen receptor complex shows significantly elevated membrane levels of IgM in neonatal B cells, compared with adult cells. CD79, which acts as the signal transducer for membrane immunoglobulin, is elevated in parallel with IgM, while IgD is elevated to a lesser degree. CD19, CD21, CD22 and CD81, which are all involved in transmitting activation signals when immunoglobulin is engaged, are not elevated. CD32, which is involved in negative regulation of activation, is present at reduced levels on cord B cells. The elevation of B‐cell membrane IgM persists during infancy. Neonatal B cells respond in vitro to interleukin‐4 (IL‐4) by further elevation of membrane IgM levels. The elevated level of membrane IgM may make neonatal B cells easier to trigger by low concentrations of antigen, but in vitro activation and immunoglobulin modulation experiments did not show significant differences between cord and adult B‐cell responses to anti‐IgM.
Apoptosis in a Fas‐resistant, T‐cell receptor‐sensitive human leukaemic T‐cell clone
Authors: DELEHANTY L. L. , PAYNE J. A. , FARROW S. N. , BROWN R. , CHAMPION B. R. 
Published: October 2004

SUMMARYThe Fas (CD95) antigen plays a key role in regulating T‐cell activation and survival. We have generated a Fas‐resistant subclone of the human T‐cell leukaemia line, H9, which is still able to undergo apoptosis in response to T‐cell receptor ligation. Molecular analyses revealed that resistance to Fas‐mediated apoptosis was due to a heterozygous mutation in the death domain of the Fas gene which generates a stop codon, and thus encodes a truncated Fas molecule. Fas ligation was able to induce apoptosis in the presence of cycloheximide, indicating that the mutant Fas molecule retained some signalling capability, which is death‐domain independent. These cells will provide a useful tool for dissecting the complexities of Fas signalling pathways.
Mouse hepatitis viral infection induces an extrathymic differentiation of the specific intrahepatic αβ‐TCRintermediate LFA‐1high T‐cell population
Authors: LAMONTAGNE L. , MASSICOTTE E. , PAGE C. 
Published: October 2004

SUMMARYMouse hepatitis virus type 3 (MHV3), a coronavirus, is an excellent model for the study of thymic and extrathymic T‐cell subpopulation disorders induced during viral hepatitis. It was recently reported that, in addition to the intrathymic T‐cell diVerentiation pathway, an extrathymic differentiation pathway of αβ‐T‐cell receptor (TCR) T lymphocytes exists in the liver, and becomes important under pathological situations such as autoimmune diseases, malignancies or hepatic bacterial infections. In the present study, we compared the phenotypes of resident hepatic, splenic or thymic T‐cell subpopulations during the acute viral hepatitis induced by MHV3 in susceptible C57BL/6 mice. The number of liver‐resident mononuclear cells (MNC) increased during the viral infection, while cellularity decreased. Single positive (SP) CD4+ cells strongly increased in both the liver and thymus, while double positive (DP) (CD4+CD8+) cells, present in the liver and thymus of mock‐infected mice, decreased in C57BL/6 mice during the viral infection. A shift of αβ‐TCRintermediate T cells toward αβ‐TCRhigh was evidenced in the liver and thymus of infected mice, but not in the spleen. The few αβ‐TCRint double negative (DN) (CD4‐CD8‐) cells also decreased following viral infection. αβ‐TCRint or high lymphocytes expressing high levels of leucocyte function antigen‐1 (LFA‐1) increased in the liver of MHV3‐infected mice. In addition, liver‐resident T cells expressed strongly the CD44 (Pgp‐1) activation marker, suggesting that they were either activated or antigen experienced during the viral infection. No significant change in T‐cell subpopulations was detected in the spleen, suggesting that MHV3 infection could induce an early in situ differentiation of resident hepatic T cells rather than a recruitment of lymphocytes from peripheral lymphoid organs.
Suppression of murine thyroiditis via blockade of the CD40–CD40L interaction
Authors: CARAYANNIOTIS G. , MASTERS S. R. , NOELLE R. J. 
Published: October 2004

SUMMARYThe CD40 ligand (gp39) is transiently expressed on activated CD4+ T cells and mediates cognate helper function by interacting with CD40 on B cells. Increasing evidence suggests, however, critical involvement of gp39 not only in antibody‐mediated responses but also in the development of effector T cells. Here, we have investigated the effect of in vivo gp39 blockade on the induction of murine experimental autoimmune thyroiditis (EAT), a T‐cell‐mediated disease. Over a 5‐week period, EAT was induced in SJL mice with thyroglobulin (Tg) and adjuvant. Concomitantly, mice received intraperitoneal (i.p.) injections of MR1, a gp39‐specific hamster monoclonal antibody (mAb), at 4‐day intervals. Control mice were challenged with Tg but received equivalent doses of hamster immunoglobulin (HIg). It was observed that the control mice developed severe thyroiditis whereas the MR1‐treated mice exhibited very low levels of infiltration that were mostly focal in nature. Blockade of gp39 was effective since the Tg‐specific IgG titres were low or undetectable in all MR1‐treated animals compared with the controls. In addition, upon restimulation with Tg in vitro, lymph node cells (LNC) from Tg‐primed, MR1‐treated mice proliferated less strongly and secreted significantly lower amounts of interleukin‐2 (IL‐2) and interferon‐γ (IFN‐γ) than LNC from untreated or HIg‐treated controls. These results strongly suggest that in vivo blockade of gp39 suppresses EAT by inhibiting the priming of inflammatory Tg‐specific T‐helper type 1 cells.
Demonstration of cytoplasmic CD32 (FcγRII) within human lymphocytes following microwave treatment
Authors: SANDILANDS G. P. , BURNETT E. R. , MACPHERSON S. A. , DOWNIE I. , MORE I. A. R. , MACSWEEN R. N. M. 
Published: October 2004

SUMMARYWe have recently described a cytoplasmic form of CD32 (FcγRII) within the vast majority of normal human peripheral blood lymphocytes (PBL) including T cells. The function of cytoplasmic CD32 is not known. These flow cytometric studies were conducted using single cell suspensions of PBL that had been prefixed and permeabilized using methanol/triton‐X‐100. In this study we have attempted to visualize cytoplasmic CD32 by immunocytochemistry using normal PBL processed in various ways and have also looked for CD32 within tissue lymphocytes. Weak cytoplasmic CD32 staining was observed in paraffin sections of normal lymphocytes but only when sections were microwave treated. The intensity of staining for CD32 did however, appear to be much stronger within infiltrating lymphocytes found in autoimmune diseases or in rejecting allografts: an observation that suggests that up‐regulation of cytoplasmic CD32 may occur when T cells become activated in vivo. Microwave treatment of PBL suspensions was shown to disrupt the outer cell membrane, thus effectively permeabilizing the cell and allowing for the detection of cytoplasmic components, like CD32, by flow cytometry. Microwave treatment may, therefore, afford an alternative method for cell permeabilization and may prove to be a useful method for the study of cytoplasmic molecules in cell suspensions and in paraffin‐embedded tissues.
Pentoxifylline in vivo and in vitro down‐regulates the expression of the intercellular adhesion molecule‐1 in monocytes
Authors: NEUNER P. , KLOSNER G. , POURMOJIB M. , KNOBLER R. , SCHWARZ T. 
Published: October 2004

SUMMARYSince pentoxifylline (PTX) was recently recognized as a substance with antiinflammatory capacities, we studied the in vivo and in vitro effect of PTX on the expression of the intercellular adhesion molecule‐1 (ICAM‐1) on human monocytes. For this purpose four healthy volunteers were treated with PTX (5×400 mg/day) for 2 days. Monocytes were isolated before and after PTX treatment and ICAM‐1 expression was investigated. As shown by fluorescence‐activated cell sorter (FACS) analysis, cultured monocytes isolated after oral application of PTX expressed significantly decreased amounts of ICAM‐1 when compared with monocytes collected prior to oral PTX application. Northern blot analysis revealed reduced amounts of ICAM‐1 mRNA in monocytes derived from volunteers after oral PTX treatment in comparison with monocytes isolated before oral PTX administration. Similarly, in monocytes treated with PTX (200 μg/ml) in vitro ICAM‐1 was found decreased both at the protein and mRNA level in comparison with untreated cells. The inhibitory effect of PTX on ICAM‐1 expression in monocytes could be reversed by the addition of exogenous tumour necrosis factor‐α (TNF‐α; 200 U/ml) suggesting that ICAM‐1 down‐regulation is mediated secondary to TNF‐α suppression by PTX. The specific role of TNF‐α in mediating ICAM‐1 expression in cultured monocytes could be confirmed by the finding that a neutralizing anti‐TNF‐α antibody partially down‐regulated ICAM‐1 expression. The observed suppressive in vivo and in vitro effects of PTX on ICAM‐1 expression in monocytes may contribute to the recently described antiinflammatory effects of PTX, e.g. in sepsis or allergic contact dermatitis.
Modulatory effect of interleukin‐10 on the production of platelet‐activating factor and superoxide anions by human leucocytes
Authors: BUSSOLATI B. , MARIANO F. , MONTRUCCHIO G. , PICCOLI G. , CAMUSSI G. 
Published: October 2004

SUMMARYWe observed that human monocytes (MO) and polymorphonuclear neutrophils (PMN) stimulated by lipopolysaccharide (LPS) produce platelet‐activating factor (PAF) in a pattern characterized by an early and a delayed peak of synthesis. The early peak of PAF synthesis was due to a direct stimulation of these cells through mCD14 receptor as it was inhibited by anti‐CD14 monoclonal antibody. The delayed and sustained peak of PAF synthesis was dependent on protein synthesis and cytokine production as shown by the inhibitory effect of cycloheximide on both MO and PMN, and of anti‐tumour necrosis factor‐α (anti‐TNF‐α) and of anti‐interleukin‐8 (anti‐IL‐8) neutralizing antibodies on MO and PMN respectively. IL‐10 completely prevented this second, cytokine‐dependent peak of PAF synthesis. In contrast, IL‐10 markedly enhanced the first peak of PAF synthesis both in MO and PMN. Moreover, IL‐10 was shown to modulate the production of superoxide anions (O‐2) on both MO and PMN. As suggested by previous studies, IL‐10 inhibited the delayed production of O‐2. In the present study, we observed that IL‐10 directly stimulated an early production of O‐2. In addition, IL‐10 enhanced the synthesis of O‐2 by MO and PMN challenged with LPS. The IL‐10‐induced O‐2 production was dependent, at least in part, from its effect on PAF synthesis, as it was inhibited by the PAF receptor antagonist WEB 2170. These results suggest that IL‐10 may upregulate the early synthesis of PAF and O‐2 triggered by direct LPS stimulation, whereas it may downregulate the delayed production of these mediators.
The β1 integrin, very late activation antigen‐4 on human neutrophils can contribute to neutrophil migration through connective tissue fibroblast barriers
Authors: GAO J.‐X. , ISSEKUTZ A. C. 
Published: October 2004

SUMMARYPolymorphonuclear leucocyte (PMNL) accumulation in extravascular tissues and inflammatory exudates is dependent on their migration through blood vessel endothelium and then through connective tissue. Previously we utilized a barrier of human synovial and dermal fibroblasts (HSF or HDF) grown on microporous filters, as a model of PMNL migration through connective tissue. Those studies showed that β2 (CD18) and the β1 integrins, very late activation antigen‐5 (VLA‐5) and VLA‐6, in part mediate this PMNL migration. Here we report that VLA‐4, which can also be expressed at low levels on activated PMNL, is also involved in PMNL migration induced by C5a through fibroblast (HSF and HDF) barriers, because monoclonal antibody (mAb) to VLA‐4 significantly inhibited (by 20–30%) PMNL migration. Blocking the function of CD18, VLA‐5 or VLA‐6 was not required for detection of the VLA‐4‐mediated migration. Combination treatment with mAb to VLA‐4 and with mAb to VLA‐5 or to VLA‐6 further inhibited PMNL migration, irrespective of whether CD11/CD18 mechanisms were blocked with anti‐CD18 mAb or not. Treatment of PMNL with a peptide based on the VLA‐4‐binding domain in the CS‐1 fragment of fibronectin, but not a control peptide, inhibited PMNL migration to a comparable extent to treatment with mAb to VLA‐4. A low level of VLA‐4 was expressed on C5a‐activated PMNL, detected by immunofluorescence flow cytometry. These results suggest that VLA‐4 can be mobilized by human peripheral blood PMNL and can, in addition to VLA‐5, VLA‐6 and CD11/CD18 integrins, mediate PMNL migration through connective tissue. This is in marked contrast to PMNL transendothelial migration, where β1 integrins appear to play no significant role.
Cellular redox status influences both cytotoxic and NF‐κB activation in natural killer cells
Authors: VALLE BLAZQUEZ M. , LUQUE I. , COLLANTES E. , ARANDA E. , SOLANA R. , PEÑA J. , MUÑOZ E. 
Published: October 2004

SUMMARYThe role of cellular redox status in both cytotoxic activity and NF‐κ B activation in natural killer (NK) cells was investigated. The results indicate that stimulation of NK cells, either freshly isolated from peripheral blood lymphocytes (PBL) or long‐term cultured NK clones, with specific cell targets results in an increased binding activity of NF‐κB and AP‐1 transcription factors measured by gel retardation. Pretreatment of NK cells with the antioxidant pyrrolidine dithiocarbarmate (PDTC) leads to the inhibition of NF‐κB activation but the AP‐1 binding to DNA was superinduced. The inhibition of NF‐κB by PDTC paralleled with an inhibition of spontaneous cytotoxicity mediated by NK cells. Moreover, the inhibitors of serine proteases, N‐α‐tosyl‐l‐lysine chloromethyl ketone and N‐α‐tosyl‐l‐phenylalanine chloromethyl ketone, also blocked the cytolytic activity of NK cells against the sensitive target K562. In contrast, NK activity was not affected by pretreatment of the effector cells with the proteasome inhibitor N‐acetyl‐leu‐leu‐norleucinal which selectively inhibits NF‐κB activation. Altogether, these results support the hypothesis that the activation of NK cells involved transcriptional and post‐transcriptional events, and that reactive intermediates may play an important role in the molecular processes related with the generation of a cytotoxic response by NK cells.
Effectiveness of interferon beta treatment in relapsing‐remitting multiple sclerosis: an Italian cohort study
Authors: Russo Pierluigi , Paolillo Andrea , Caprino Luciano , Bastianello Stefano , Bramanti Placido 
Published: October 2004

AbstractRationale, aims and objectives  Randomized clinical trials (RCTs) have provided evidence for the efficacy of interferon beta (IFNβ) in the treatment of relapsing‐remitting multiple sclerosis (RRMS). The aim of this study was to evaluate the effectiveness of IFNβ treatment in clinical practice.Methods  This was a national, multicentre, observational study of patients with confirmed RRMS. Demographic, clinical and therapeutic data were retrospectively collected for each patient enrolled in the study.Results  The study cohort consisted of 427 patients exposed to and 245 never exposed to IFNβ treatment during the study period (for a total 2297 patient‐years of follow‐up). Among the exposed patients, 215 were initially untreated and then began IFNβ later in the follow‐up period; 137 of these patients were exposed to IFNβ for more than 2 years. In these patients, IFNβ treatment reduced the mean relapse rate by 24.2%[95% confidence interval (CI): 5.8–42.5%]. For 640 of the 672 patients enrolled in the study, it was possible to calculate the area under the disability/time curve compared to that present at baseline. A total of 117 (18.3%) patients displayed disability progression. Adjustment of the disability progression rates for potential confounders and/or for propensity scores by Poisson regression model resulted in relative risks for patients exposed to IFNβ treatment compared to those never exposed to IFNβ of 0.87 (95% CI: 0.56–1.34) after an exposure of ≤ 2 years, and of 0.35 (95% CI: 0.21–0.60) after an exposure of > 2 years.Conclusions  These findings suggest that the evidence from RCTs on the treatment of RRMS with IFNβ has been effectively translated into routine clinical practice.