bluuebunny/crossref_metadata_2025_split huggingface dataset:
Complement depletion aggravatesStaphylococcus aureussepticaemia and septic arthritis
Authors: SAKINIENE E , BREMELL T , TARKOWSKI A 
Published: March 2003

SUMMARYThe aim of the study was to assess the role of the complement system in Staphylococcus aureus arthritis and septicaemia. The murine model of haematogenously acquired septic arthritis was used, injecting intravenously toxic shock syndrome toxin-1 (TSST-1), producing S. aureus LS-1. Complement was depleted using cobra venom factor (CVF). Evaluation of arthritis was performed clinically and histopathologically. In addition, the effect of complement depletion on the phagocytic activity of leucocytes was assessed in vivo and in vitro. Six days after inoculation of S. aureus the prevalence of arthritis in decomplemented mice was three-fold higher than that in controls (91% versus 25%). The clinical severity of arthritis at the end of the experiment, expressed as arthritic index, was 7.3 and 1.9, respectively. These findings were confirmed by histological index of synovitis as well as of cartilage and/or bone destruction being significantly higher in decomplemented mice than in controls (9.8 ± 1.7 versus 4.9 ± 1.2, P &lt; 0.05; and 7.9 ± 1.7 versus 3.0 ± 0.9, P &lt; 0.05, respectively). Also, the septicaemia-induced mortality was clearly higher in decomplemented mice compared with the controls. CVF treatment significantly reduced in vivo polymorphonuclear cell-dependent inflammation induced by subcutaneous injection of olive oil and mirroring the capacity of polymorphonuclear cells (PMNC) to migrate and/or extravasate. Besides, the decomplementation procedure significantly impaired phagocytic activity of peripheral blood leucocytes in vitro, since the number of phagocytes being able to ingest bacteria decreased by 50% when the cells were maintained in decomplemented serum compared with those in intact serum. The conclusion is that complement depletion aggravates the clinical course of S. aureus arthritis and septicaemia, possibly by a combination of decreased migration/extravasation of PMNC and an impairment of phagocytosis.
Cyclooxygenase-1 and -2 are expressed by human T cells
Authors: PABLOS J L , SANTIAGO B , CARREIRA P E , GALINDO M , GOMEZ-REINO J J 
Published: March 2003

SUMMARYIn vitro, prostaglandins (PG) have strong inhibitory effects on T cell activation and proliferation and inhibitors of PG synthesis (NSAID) increase proliferation and activation of T cells. Although most studies have failed to demonstrate cyclooxygenase (COX) activity in lymphocytes, there is contradictory evidence on the synthesis of different PG. We have studied by reverse transcriptase-polymerase chain reaction (RT-PCR) and Western blot the expression of COX-1 and -2 mRNA and protein in resting and activated peripheral blood or Jurkat T cells. Cells were activated by T cell receptor triggering with OKT3 antibodies and activation confirmed by flow cytometric analysis of surface CD69. COX enzymatic activity was measured by determination of arachidonic acid (AA)-induced PG synthesis. Both peripheral blood and Jurkat T cells expressed COX-1 and -2 mRNA and protein. COX-1 was constitutively expressed and did not change after OKT3 stimulation. COX-2 was inducible upon OKT3-induced activation. In spite of the presence of COX mRNA and immunoreactive protein, AA-induced PG synthesis was not detected at the EIA detection (p m) level. The potential role of cyclooxygenases in T cells deserves further study, since no PG of the studied series seem to be synthesized by T cells.
Antibodies to adult human endothelial cells cross-react with oxidized low-density lipoprotein and β2-glycoprotein I (β2-GPI) in systemic lupus erythematosus
Authors: WU R , SVENUNGSSON E , GUNNARSSON I , HAEGERSTRAND-GILLIS C , ANDERSSON B , LUNDBERG I , ELINDER L S , FROSTEGÅRD J 
Published: March 2003

SUMMARYCardiovascular manifestations are common in systemic lupus erythematosus (SLE). Oxidized low-density lipoprotein (oxLDL) is implicated in cardiovascular disease, especially atherosclerosis, and cross-reacts with antibodies to cardiolipin (aCL). β2-GPI is a plasma protein participating in the coagulating cascade, and is also cofactor for aCL, and some aCL have been shown to be directed against β2-GPI and/or complexes between β2-GPI and phospholipids. Lysophosphatidylcholine (LPC) is a phospholipid present both in oxLDL and in damaged endothelium, and we recently showed that LPC is involved in the antigenicity of oxLDL. Antibodies to endothelial cells (aEC) correlate with disease activity in SLE and vasculitis, and we recently showed that aEC are enhanced in cardiovascular diseases such as borderline hypertension and early atherosclerosis. aEC were determined using EC from adult V. Saphena Magna. Antibody levels were determined by ELISA. aEC of IgG type were enhanced in 184 patients with SLE compared with 85 healthy controls. There was a close correlation between aoxLDL, aCL, aLPC, aβ2-GPI and aEC. Binding of sera to EC was competitively inhibited by β2-GPI, LPC and oxLDL. Taken together, the data indicate that EC share antigenic epitopes with β2-GPI and with oxLDL, especially LPC. Phospholipids in EC membranes may thus be antigenic epitopes. β2-GPI may bind to these phospholipids, and become an autoantigen. LPC is formed by oxidation of phospholipids and/or proinflammatory factors leading to activation of phospholipase A2, and the findings indicate the potential role of both lipid oxidation and phospholipase A2 in SLE.
Alzheimer's β-amyloid peptides can activate the early components of complement classical pathway in a C1q-independent manner
Authors: BERGAMASCHINI L , CANZIANI S , BOTTASSO B , CUGNO M , BRAIDOTTI P , AGOSTONI A 
Published: March 2003

SUMMARYβ-Amyloid (β-A) accumulates in the brain of patients with Alzheimer's disease (AD) and is presumably involved in the pathogenesis of this disease, on account of its neurotoxicity and complement-activating ability. Although assembly of β-A in particular aggregates seems to be crucial, soluble non-fibrillar β-A may also be involved. Non-fibrillar β-A does not bind C1q, so we investigated alternative mechanisms of β-A-dependent complement activation in vitro. On incubation with normal human plasma, non-fibrillar β-A 1-42, and truncated peptide 1–28, induced dose-dependent activation of C1s and C4, sparing C3, as assessed by densitometric analysis of immunostained membrane after SDS–PAGE and Western blotting. The mechanism of C4 activation was not dependent on C1q, because non-fibrillar β-A can still activate C1s and C4 in plasma genetically deficient in C1q (C1qd). In Factor XII-deficient plasma (F.XIId) the amount of cleaved C4 was about 5–10% less that in C1qd and in normal EDTA plasma; the reconstitution of F.XIId plasma with physiologic concentrations of F.XII resulted in an increased (8–15%) β-A-dependent cleavage of C4. Thus our results indicate that the C1q-independent activation of C1 and C4 can be partially mediated by the activation products of contact system. Since the activation of contact system and of C4 leads to generation of several humoral inflammatory peptides, non-fibrillar β-A might play a role in initiating the early inflammatory reactions leading to a multistep cascade contributing to neuronal and clinical dysfunction of AD brain.
Are anti-neutrophil cytoplasmic antibodies (ANCA) clinically useful in inflammatory bowel disease (IBD)?
Authors: ROOZENDAAL C , KALLENBERG C G M 
Published: March 2003

SUMMARYSince the first detection of ANCA in IBD, numerous studies have dealt with their prevalence, antigenic specificities, clinical significance, pathophysiological role, and their induction. This review summarizes the information obtained from those studies and shows that ANCA are not directly useful as diagnostic and prognostic factors in IBD. ANCA were detected in 50–85% of patients with ulcerative colitis (UC) and 10–20% of patients with Crohn's disease (CD). Multiple target antigens are recognized by these autoantibodies, including both cytoplasmic and nuclear proteins. A pathophysiological role for ANCA in IBD is far from clear. On the one hand, it is suggested that ANCA are genetic markers of susceptibility for IBD, and on the other hand, the induction of ANCA in those diseases may just be an epiphenomenon of chronic inflammation. We discuss recent evidence that ANCA may be induced by a break-through of tolerance towards bacterial antigens.
Presence of circulating abnormal CD34+ progenitors in adult Langerhans cell histiocytosis
Authors: MISERY L , ROUGIER N , CRESTANI B , FAURE M , CLAUDY A , SCHMITT D , VINCENT C 
Published: March 2003

SUMMARYLangerhans cell histiocytosis (LCH) is related to the proliferation of cells, which are similar to Langerhans cells (LC) but possess many abnormal characteristics. Lesions are widespread and this fact suggests that LCH cells or their precursors are present in the blood of patients. In five adult patients, we have isolated and cultured CD34+ blood progenitors of dendritic cells. We studied their phenotype by flow cytometry and their functional properties in mixed culture with heterologous lymphocytes and with autologous lymphocytes in the presence of tri-nitro-phenyl antigen (TNP). The amount of CD34+ precursors was dramatically higher than controls but a high mortality occurred during the in vitro differentiation. The phenotype of surviving cells was similar to LC phenotype (CD1a+, CD83+, Lag+) but some of them expressed CD2. These cells were able to induce T cell proliferation in mixed culture. They could not initiate primary response to TNP, except in a patient treated with thalidomide. In our hands, these CD34+ cells may be precursors of LCH cells.
Sodium butyrate blocks interferon-gamma (IFN-γ)-induced biosynthesis of MHC class III gene products (complement C4 and factor B) in human fetal intestinal epithelial cells
Authors: Kitamura K , Andoh A , Inoue T , Amakata Y , Hodohara K , Fujiyama Y , Bamba T 
Published: March 2003

SUMMARYHuman intestinal epithelial cells have been established as local sites for complement biosynthesis. In this study, we investigated the effects of IFN-γ and sodium butyrate on biosynthesis of MHC class III gene products (complement C4 and factor B) in the human fetal intestinal epithelial cell line INT-407. IFN-γ induced a dose- and time-dependent increase in C4 and factor B secretion. However, sodium butyrate dose-dependently inhibited IFN-γ-induced C4 and factor B secretion. These effects were also observed at the mRNA level. Immunoblotting indicated that IFN-γ induced a rapid activation of Stat1α, and fluorescence immunohistochemistry detected a translocation of Stat1α into the nucleus within 1 h. However, the translocation of Stat1α was not affected by the addition of sodium butyrate. Nuclear run-on assay indicated that IFN-γ induced a weak increase in the transcription rate of factor B gene, and sodium butyrate did not affect this response. IFN-γ and sodium butyrate induced a counter-regulatory effect on C4 and factor B secretion: IFN-γ acted as a potent inducer, but sodium butyrate potently abrogated these responses. These are mainly regulated through the post-transcriptional mechanism.
Onchocerciasis modulates the immune response to mycobacterial antigens
Authors: Stewart G R , Boussinesq M , Coulson T , Elson L , Nutman T , Bradley J E 
Published: March 2003

SUMMARYChronic helminth infection induces a type-2 cellular immune response. In contrast to this, mycobacterial infections commonly induce a type-1 immune response which is considered protective. Type-2 responses and diminished type-1 responses to mycobacteria have been previously correlated with active infection states such as pulmonary tuberculosis and lepromatous leprosy. The present study examines the immune responses of children exposed to both the helminth parasite Onchocerca volvulus and the mycobacterial infections, Mycobacterium tuberculosis and M. leprae. Proliferation of peripheral blood mononuclear cells (PBMC) and production of IL-4 in response to both helminth and mycobacterial antigen (PPD) decreased dramatically with increasing microfilarial (MF) density. Although interferon-gamma (IFN-γ) production strongly correlated with cellular proliferation, it was surprisingly not related to MF density for either antigen. IL-4 production in response to helminth antigen and PPD increased with ascending children's age. IFN-γ and cellular proliferation to PPD were not related to age, but in response to helminth antigen were significantly higher in children of age 9–12 years than children of either the younger age group (5–8 years) or the older group (13–16 years). Thus, there was a MF density-related down-regulation of cellular responsiveness and age-related skewing toward type 2 which was paralleled in response to both the helminth antigen and PPD. This parasite-induced immunomodulation of the response to mycobacteria correlates with a previous report of doubled incidence of lepromatous leprosy in onchocerciasis hyperendemic regions. Moreover, this demonstration that helminth infection in humans can modulate the immune response to a concurrent infection or immunological challenge is of critical importance to future vaccination strategies.
Analysis of the secretion pattern of monocyte chemotactic protein-1 (MCP-1) and transforming growth factor-beta 2 (TGF-β2) by human retinal pigment epithelial cells
Authors: Holtkamp G M , De Vos A F , Peek R , Kijlsta A 
Published: March 2003

SUMMARYRetinal pigment epithelial (RPE) cells, situated between the neurosensory retina and the vascularized choroid, form part of the blood–eye barrier and are important for homeostasis of the outer retina. These cells are able to produce a variety of cytokines which may play a role in the maintenance of the immunosuppressive milieu inside the eye and in intraocular inflammatory responses. In the present study, we investigated whether RPE cells secreted the anti-inflammatory cytokine TGF-β2 and the proinflammatory cytokine MCP-1 in a polarized manner. Monolayers of human donor RPE cells were cultured on transwell filters. Secretion of TGF-β2 and MCP-1 at either the apical or basal side of the RPE cell monolayers, that were not treated or stimulated with IL-1β (200 U/ml), was analysed by ELISA. All three cell lines examined had a different TGF-β2 secretion pattern. In two of the three donor RPE cell lines tested, TGF-β2 secretion was polarized, but not in the same direction. TGF-β2 secretion was not up-regulated by stimulation with IL-1β. In contrast, IL-1β strongly induced MCP-1 secretion preferentially into the basal compartment of all RPE monolayers tested. These data indicate that human RPE cells are able to secrete TGF-β2 and MCP-1 in a polarized fashion. Our results suggest that MCP-1 can be secreted by RPE cells in the direction of choroidal vessels during inflammatory responses in the posterior part of the eye, which may limit damage to the neurosensory retina.
Externalization of tropomyosin isoform 5 in colon epithelial cells
Authors: Kesari K V , Yoshizaki N , Geng X , Lin J J-C , Das K M 
Published: March 2003

SUMMARYUlcerative colitis (UC) is associated with autoantibody response to a cytoskeletal protein, human tropomyosin (hTM) isoform-5 (hTM5). Because hTM5 is an intracellular protein, it may remain inaccessible to the autoantibodies. Therefore, we have investigated the possibility of externalization of hTM5 in colon epithelial cells. Freshly isolated colonic and small intestinal epithelial cells and LS-180 colon cancer cell line were examined for surface expression of hTM5 by flow cytometric analysis using hTM isoform-specific MoAbs. The extracellular release of hTM5 was determined by Western blot and radioimmunoprecipitation analyses. Physical association of hTM5 with a membrane-associated colon epithelial protein (CEP) was examined by co-immunoprecipitation of hTM5 with anti-CEP MoAb, and CEP with anti-hTM5 MoAb. Cell surface expression of hTM5 was observed in colonic epithelial and LS-180 cells but not in small intestinal epithelial cells. LS-180 cells spontaneously released hTM5 as well as CEP into the culture medium that was significantly stimulated by a calcium ionophore, A23187, but inhibited by phorbol-12-myristate-13-acetate, monensin and methylamine. Co-immunoprecipitation experiments revealed that hTM5 forms a complex with CEP. We conclude that hTM5 is externalized in colon but not in small intestinal epithelial cells. The physical association of hTM5 with CEP suggests a possible chaperone function of CEP in the transport of hTM5, a putative target autoantigen in UC.
Molecular determinants of polyreactive antibody binding: HCDR3 and cyclic peptides
Authors: Deng Y-J , Notkins A L 
Published: March 2003

SUMMARYHuman monoclonal antibody 63 (mAb63) is an IgM/λ polyreactive antibody that binds to multiple self and non-self antigens. The molecular basis of polyreactivity is still unclear. The present study was initiated to prepare a recombinant Fab of mAb63 and use it to study the determinants involved in polyreactivity. The baculovirus system was employed to express large amounts of mAb63 Fab in Sf9 cells. Our experiments showed that infected Sf9 cells secreted a soluble 50-kD Fab heterodimer that bound to multiple self and non-self antigens. The antigen-binding activity of mAb63 Fab was inhibited by both homologous and heterologous antigens. To study in more detail the molecular determinants involved in polyreactivity, the heavy chain complementarity-determining region 3 (HCDR3), which is known to play a key role in the binding of monoreactive antibodies to antigens, was subjected to site-directed mutagenesis. A single substitution, alanine for arginine, at position 100A resulted in complete loss of antigen-binding activity. The 19 amino acids comprising the HCDR3 of mAb63 were then synthesized and a cyclic peptide prepared. The cyclic peptide showed the same antigen-binding pattern as the parental mAb63 and the recombinant mAb63 Fab. A five amino acid motif (RFLEW), present in the HCDR3 of mAb63, was found by searching the GenBank in three of 50 other human polyreactive antibodies, but in none of nearly 2500 human antibodies thought to be monoreactive. It is concluded that HCDR3 plays a major role in polyreactivity and that in some cases cyclic peptides comprising the HCDR3, by themselves, may be polyreactive.
Interferon-alpha (IFN-α) stimulates anti-melanoma cytotoxic T lymphocyte (CTL) generation in mixed lymphocyte tumour cultures (MLTC)
Authors: Palmer K J , Harries M , Gore M E , Collins M K L 
Published: March 2003

SUMMARYIFN-α administration after primary tumour resection improves the survival of melanoma patients at high risk of relapse. To investigate whether this response might be due to stimulation of anti-tumour immunity, the effect of IFN-α on anti-melanoma CTL generation in MLTC was measured. IFN-α increased both allogeneic and autologous anti-melanoma CTL generation from peripheral blood lymphocytes stimulated with irradiated primary melanoma cultures. IFN-α up-regulated MHC class I expression on primary melanoma cultures, whereas IFN-γ up-regulated both MHC class I and II expression. However, the effect of IFN-α on anti-melanoma CTL generation was often more potent than that of IFN-γ, equalling the effect of the optimal combination of IL-2 and IL-12. Pre-treatment of primary melanoma cultures with IFN-γ was sufficient for CTL generation in MLTC, whereas IFN-α needed to be present during the MLTC. While direct anti-proliferative effects of IFN-α on some tumour cells have been described, IFN-α did not inhibit proliferation of primary melanoma cultures. These results suggest that the clinical effects of IFN-α in melanoma patients may be immune-mediated.
Effect of IL-5, glucocorticoid, and Fas ligation on Bcl-2 homologue expression and caspase activation in circulating human eosinophils
Authors: Zangrilli J , Robertson N , Shetty A , Wu J , Hastie A , Fish J E , Litwack G , Peters S P 
Published: March 2003

SUMMARY
IL-5 is a potent eosinophil viability-enhancing factor that has been strongly implicated in the pathogenesis of IgE-mediated inflammation in vivo. Recently published data have suggested that IL-5 (and related cytokines) may act by altering the expression of the anti-apoptotic regulator Bcl-2 or its homologues, but this is controversial. The behaviour of the recently described pro-apoptotic cysteine proteases (caspases) in eosinophils after IL-5 treatment has not been explored. We examined the effect of IL-5 on the expression of four major Bcl-2 homologues, as well as on the expression/activation of key members of the caspase cell death cascade in cultured circulating human eosinophils. The effect of relevant inducers of eosinophil apoptosis (glucocorticoid and Fas ligation) on these regulatory proteins was also examined. We observed baseline expression of the anti-apoptotic Mcl-1 and pro-apoptotic Bax proteins in immunoblots of eosinophil lysates, but not Bcl-x, Bcl-2. IL-5 treatment had the effect of maintaining this basal level of expression over time without altering the balance of Bcl-2 homologues. The (upstream) caspase 8 and (downstream) caspase 3 proenzymes were detected in eosinophils at baseline, and were processed during spontaneous and stimulated eosinophil death. IL-5 completely blocked caspase processing in spontaneous and dexamethasone-induced cell death, and significantly slowed processing during Fas ligation. Our data do not support the theory that IL-5 acts by altering the balance of anti-apoptotic and pro-apoptotic Bcl-2 homologues, but suggest that it may act by regulating activation of the caspase cell death cascade.
Immunohistochemical study of lymphoid tissues in adjuvant arthritis (AA) by image analysis; relationship with synovial lesions
Authors: Carol M , Pelegrí C , Castellote C , Franch A , Castell M 
Published: March 2003

SUMMARYThe aim of this study was to examine leucocyte populations in lymphoid organs during AA and to ascertain the relationship with lesions in synovial joints. Popliteal lymph nodes, spleen and knee synovial membranes were removed from both healthy and AA rats at intervals of 3–4 days over a 3-week period. Cryostat sections were stained with MoAbs directed against lymphocyte and macrophage subpopulations, and studied by image analysis. Throughout the arthritic period, high numbers of ED1+ and ED3+ macrophages were seen in both lymphoid compartments and intercellular adhesion molecule-1 (ICAM-1) expression also increased in some zones of lymph nodes and spleen. The percentages of CD4+ and CD8+ cells rose in the splenic zones studied but fell in the lymph node cortex. Very few natural killer (NK) cells were found in lymphoid tissues, but the number rose after AA induction. In synovia from AA rats, ED2+ macrophages proliferated but α/β T cell infiltration was only occasionally observed, accompanied by ED1+ cells and ICAM-1 expression. In conclusion, synovitis developing after AA induction seems to be caused directly by macrophages and indirectly by lymphocytes placed both in popliteal lymph nodes and spleen.