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ID PMID Title PublicationDate abstract
9301522 Differential functional effects of a humanized anti-CD4 antibody on resting and activated 1997 Jul A fully humanized immunoglobulin G1 (IgG1) anti-CD4 monoclonal antibody is currently being evaluated in phase I/II clinical trials for rheumatoid arthritis. In order to understand the mode of action of this antibody in vivo, we have carried out a detailed functional analysis in vitro of the effects of this antibody on T-cell activation. The anti-CD4 antibody was found to inhibit both antigen-specific responses involving recognition of human leucocyte antigen (HLA) class II and processed antigenic peptides as well as non-class II dependent responses via anti-CD3 antibodies. The antibody did not cause total blockade of T-cell proliferation, but rather induced a shift in the dose-response curve, decreasing the sensitivity of cells to antigen or anti-CD3-mediated stimulation. The antibody appears to allow at least a partial early signal into the T cell as it does not inhibit the increase in tyrosine phosphorylation induced by anti-CD3 antibodies. A comparison of the intact antibody with that of either the F(ab')2 fragment or an engineered non-Fc receptor (FcR) binding form revealed that the intact antibody was the most effective at inhibiting proliferation of resting peripheral blood CD4+ T cells. However, this difference was only apparent when excess antibody was removed from culture prior to antigen or anti-CD3 mediated stimulation. The intact antibody induced both CD4 down-modulation and increases in CD4-associated tyrosine phosphorylation of resting CD4+ T cells, which were not seen with the non-FcR binding versions, which may account for the enhanced potency of the intact antibody at inhibiting T-cell activation. Interestingly, the anti-CD4 antibody induced a differential effect on activated CD4+ T cell clones compared with resting CD4+ T cells with respect to degree of CD4 cross-linking required to induce functional effects in the T cell. Both intact and non-FcR binding antibodies were equally effective at inhibiting T-cell proliferation of activated T-cell clones. In addition CD4 down-modulation and increased CD4-associated tyrosine phosphorylation were observed with T-cell clones in the absence of secondary cross-linking. Such observations may be of relevance when studying the effects of the antibody at sites of inflammation, where there will be CD4+ T cells of differing activation states as well as varying numbers of FcR positive cells.
9177931 Serum content of the C-propeptide of the cartilage molecule type II collagen in children. 1997 May OBJECTIVE: The C-propeptide of cartilage type II procollagen, together with the N-propeptide, are removed from newly synthesized procollagen during collagen fibril assembly in cartilage matrix. The presence and content of the C-propeptide reflect the synthesis of this molecule. Recently, we showed that serum levels of the C-propeptide are increased in adults with rheumatoid arthritis, pointing to increased synthesis of this molecule. In this study we examined its content in the sera of children to determine whether it changes during development. METHODS: Sera were obtained from 44 premature infants (cord blood), 75 children (0-18 years), 14 young adults (18-22 years) and 47 adults (35-60 years). The concentration of serum C-propeptide of type II procollagen was determined by a solution phase competitive inhibition radioimmunoassay which uses a polyclonal antiserum specific for the bovine and human C-propeptide. RESULTS: Compared with adults, concentrations of the C-propeptide of type II procollagen were significantly elevated in children of ages 0-14 years. Concentrations were constant until 10 years of age (premature infants: 14.5 +/- 1.4 ng/ml, mean +/- SE; 0-10 years: 13.6 +/- 1 ng/ml). In children of ages 10-14 years, during which the pubertal growth spurt is ordinarily observed, the mean concentration increased (10-14 years: 21.6 +/- 0.7 ng/ml) although not significantly due to the variation between individuals. Concentrations at all ages younger than 14 were significantly greater than those in older adolescents ages 14-18 (6.3 +/- 0.7 ng/ml), young adults (8.4 +/- 2.0 ng/ml) and adults (5.7 +/- 0.4 ng/ml). Serum concentrations did not show significant differences with respect to sex, but varied from child to child at any given age. CONCLUSIONS: The measurement of this circulating C-propeptide may be of use in studying the biochemical and physiological bases of changes in cartilage turnover in children, and abnormalities thereof.
11308397 Identification of a novel common genetic risk factor for lumbar disk disease. 2001 Apr 11 CONTEXT: Lumbar disk disease (LDD) is one of the most common musculoskeletal diseases, with a prevalence of about 5%. A tryptophan (Trp) allele (Trp2) was recently discovered in the COL9A2 gene that is associated with dominantly inherited LDD but is only present in about 4% of Finnish patients with LDD. OBJECTIVE: To determine if other collagen IX gene sequence variations play a role in the pathogenesis of LDD. DESIGN AND SETTING: Case-control study conducted from February 1997 to May 1998 at university hospitals in Finland. PARTICIPANTS: A total of 171 individuals with LDD (evaluated clinically and by magnetic resonance imaging or computed tomography) and 321 controls without LDD (186 healthy individuals, 83 patients with primary osteoarthritis, 31 with rheumatoid arthritis, and 21 with chondrodysplasias). MAIN OUTCOME MEASURES: Frequencies of sequence variations covering the entire coding sequences and exon boundaries of the collagen IX genes, COL9A1, COL9A2, and COL9A3, which code for the alpha1, alpha2, and alpha3 chains of the protein, detected by conformation-sensitive gel electrophoresis and confirmed by sequencing, compared between individuals with and without LDD. RESULTS: Mutation analysis of all 3 collagen IX genes resulted in identification of an Arg103-->Trp (arginine-->tryptophan) substitution in the alpha3 chain (Trp3 allele). The frequency of the Trp3 allele was 12.2% in LDD cases, excluding 7 individuals who were carriers of the previously identified Gln326-->Trp (glutamine-->tryptophan) substitution in the alpha2 chain (Trp2 allele), and was 4.7% among controls. The difference in the frequency was statistically significant (P =.000013). Presence of at least 1 Trp3 allele increases risk of LDD about 3-fold. CONCLUSION: This study led to the identification of a novel common genetic risk factor for LDD, confirming that genetic risk factors likely play a significant role in LDD.
10687887 Vegan proteins may reduce risk of cancer, obesity, and cardiovascular disease by promoting 1999 Dec Amino acids modulate the secretion of both insulin and glucagon; the composition of dietary protein therefore has the potential to influence the balance of glucagon and insulin activity. Soy protein, as well as many other vegan proteins, are higher in non-essential amino acids than most animal-derived food proteins, and as a result should preferentially favor glucagon production. Acting on hepatocytes, glucagon promotes (and insulin inhibits) cAMP-dependent mechanisms that down-regulate lipogenic enzymes and cholesterol synthesis, while up-regulating hepatic LDL receptors and production of the IGF-I antagonist IGFBP-1. The insulin-sensitizing properties of many vegan diets--high in fiber, low in saturated fat--should amplify these effects by down-regulating insulin secretion. Additionally, the relatively low essential amino acid content of some vegan diets may decrease hepatic IGF-I synthesis. Thus, diets featuring vegan proteins can be expected to lower elevated serum lipid levels, promote weight loss, and decrease circulating IGF-I activity. The latter effect should impede cancer induction (as is seen in animal studies with soy protein), lessen neutrophil-mediated inflammatory damage, and slow growth and maturation in children. In fact, vegans tend to have low serum lipids, lean physiques, shorter stature, later puberty, and decreased risk for certain prominent 'Western' cancers; a vegan diet has documented clinical efficacy in rheumatoid arthritis. Low-fat vegan diets may be especially protective in regard to cancers linked to insulin resistance--namely, breast and colon cancer--as well as prostate cancer; conversely, the high IGF-I activity associated with heavy ingestion of animal products may be largely responsible for the epidemic of 'Western' cancers in wealthy societies. Increased phytochemical intake is also likely to contribute to the reduction of cancer risk in vegans. Regression of coronary stenoses has been documented during low-fat vegan diets coupled with exercise training; such regimens also tend to markedly improve diabetic control and lower elevated blood pressure. Risk of many other degenerative disorders may be decreased in vegans, although reduced growth factor activity may be responsible for an increased risk of hemorrhagic stroke. By altering the glucagon/insulin balance, it is conceivable that supplemental intakes of key non-essential amino acids could enable omnivores to enjoy some of the health advantages of a vegan diet. An unnecessarily high intake of essential amino acids--either in the absolute sense or relative to total dietary protein--may prove to be as grave a risk factor for 'Western' degenerative diseases as is excessive fat intake.
10674961 Characterization of bone resorbing activity in gingival crevicular fluid from patients wit 2000 Jan BACKGROUND: In attempts to elucidate factors stimulating bone resorption in patients with different inflammatory diseases in the vicinity of the skeleton, e.g., peridontal disease and rheumatoid arthritis, we are investigating the presence of bone-resorbing activity in a variety of inflammatory exudates. The aim of the present study was to characterize the bone-resorbing activity present in patients with periodontitis. METHODS: Bone-resorbing activity was assessed in gingival crevicular fluids (GCFs) collected from patients with periodontitis and from patients with no signs of gingivitis. Bone-resorbing activity was evaluated by analyzing the capacity of GCFs to stimulate the release of minerals and the breakdown of bone matrix proteins in cultured neonatal mouse calvariae. The concentrations of IL-1alpha, IL-1beta and PGE2 were determined with ELISA and RIA techniques, respectively. RESULTS: GCF eluates from 24 different healthy sites caused a 1.23+/-0.05 fold stimulation of 45Ca release, whereas GCF eluates from 45 different diseased (periodontitis) sites caused a 2.46+/-0.10 fold stimulation. The effect on 45Ca release was time- and concentration-dependent, inhibited by 3 different osteoclast inhibitors and associated with enhanced release of 3H from [3H]-proline-labelled bones. The activity in GCF causing enhanced 45Ca release was unaffected, or in some samples partially reduced, by ultrafiltration using a filter with a molecular weight cut-off of 3000 Daltons. The bone-resorbing activity was temperature sensitive (+90degrees C, 10 min). The concentrations of prostaglandin E2 (PGE2) in the diluted GCF eluates, used in the bone resorption bioassay, were too low to be responsible for the release of 45Ca. Antisera specifically neutralizing human IL-1a inhibited the stimulatory effect of GCF pooled from several diseased sites. The specific, recombinant human IL-1 receptor antagonist completely inhibited the effect of pooled GCFs. GCF eluates from diseased sites contained human IL-1alpha and IL-1beta at concentrations of 1838+/-294 pg/ml and 512+/-91 pg/ml, respectively. CONCLUSIONS: These data show that GCF contains activity(ies) stimulating osteoclastic bone resorption in vitro. The factor primarily responsible for this activity seems to be IL-1alpha, but IL-1alpha is not the sole activator of bone resorption in GCF.
10543949 Crystal structure of the stromelysin catalytic domain at 2.0 A resolution: inhibitor-induc 1999 Oct 29 Matrix metalloproteinases are believed to play an important role in pathological conditions such as osteoarthritis, rheumatoid arthritis and tumor invasion. Stromelysin is a zinc-dependent proteinase and a member of the matrix metalloproteinase family. We have solved the crystal structure of an active uninhibited form of truncated stromelysin and a complex with a hydroxamate-based inhibitor. The catalytic domain of the enzyme of residues 83-255 is an active fragment. Two crystallographically independent molecules, A and B, associate as a dimer in the crystals. There are three alpha-helices and one twisted, five-strand beta-sheet in each molecule, as well as one catalytic Zn, one structural Zn and three structural Ca ions. The active site of stromelysin is located in a large, hydrophobic cleft. In particular, the S1' specificity site is a deep and highly hydrophobic cavity. The structure of a hydroxamate-phosphinamide-type inhibitor-bound stromelysin complex, formed by diffusion soaking, has been solved as part of our structure-based design strategy. The most important feature we observed is an inhibitor-induced conformational change in the S1' cavity which is triggered by Tyr223. In the uninhibited enzyme structure, Tyr223 completely covers the S1' cavity, while in the complex, the P1' group of the inhibitor displaces the Tyr223 in order to fit into the S1' cavity. Furthermore, the displacement of Tyr223 induces a major conformational change of the entire loop from residue 222 to residue 231. This finding provides direct evidence that Tyr223 plays the role of gatekeeper of the S1' cavity. Another important intermolecular interaction occurs at the active sit of molecule A, in which the C-terminal tail (residues 251-255) from molecule B inserts. The C-terminal tail interacts extensively with the active site of molecule A, and the last residue (Thr255) coordinated to the catalytic zinc as the fourth ligand, much like a product inhibitor would. The inhibitor-induced conformational change and the intermolecular C-terminal-zinc coordination are significant in understanding the structure-activity relationships of the enzyme.
9854452 Anti-inflammatory actions of glucocorticoids: molecular mechanisms. 1998 Jun 1. Glucocorticoids are widely used for the suppression of inflammation in chronic inflammatory diseases such as asthma, rheumatoid arthritis, inflammatory bowel disease and autoimmune diseases, all of which are associated with increased expression of inflammatory genes. The molecular mechanisms involved in this anti-inflammatory action of glucocorticoids is discussed, particularly in asthma, which accounts for the highest clinical use of these agents. 2. Glucocorticoids bind to glucocorticoid receptors in the cytoplasm which then dimerize and translocate to the nucleus, where they bind to glucocorticoid response elements (GRE) on glucocorticoid-responsive genes, resulting in increased transcription. Glucocorticoids may increase the transcription of genes coding for anti-inflammatory proteins, including lipocortin-1, interleukin-10, interleukin-1 receptor antagonist and neutral endopeptidase, but this is unlikely to account for all of the widespread anti-inflammatory actions of glucocorticoids. 3. The most striking effect of glucocorticoids is to inhibit the expression of multiple inflammatory genes (cytokines, enzymes, receptors and adhesion molecules). This cannot be due to a direct interaction between glucocorticoid receptors and GRE, as these binding sites are absent from the promoter regions of most inflammatory genes. It is more likely to be due to a direct inhibitory interaction between activated glucocorticoid receptors and activated transcription factors, such as nuclear factor-kappa B and activator protein-1, which regulate the inflammatory gene expression. 4. It is increasingly recognized that glucocorticoids change the chromatin structure. Glucocorticoid receptors also interact with CREB-binding protein (CBP), which acts as a co-activator of transcription, binding several other transcription factors that compete for binding sites on this molecule. Increased transcription is associated with uncoiling of DNA wound around histone and this is secondary to acetylation of the histone residues by the enzymic action of CBP. Glucocorticoids may lead to deacetylation of histone, resulting in tighter coiling of DNA and reduced access of transcription factors to their binding sites, thereby suppressing gene expression. 5. Rarely patients with chronic inflammatory diseases fail to respond to glucocorticoids, although endocrine function of steroids is preserved. This may be due to excessive formation of activator protein-1 at the inflammatory site, which consumes activated glucocorticoid receptors so that they are not available for suppressing inflammatory genes. 6. This new understanding of glucocorticoid mechanisms may lead to the development of novel steroids with less risk of side effects (which are due to the endocrine and metabolic actions of steroids). 'Dissociated' steroids which are more active in transrepression (interaction with transcription factors) than transactivation (GRE binding) have now been developed. Some of the transcription factors that are inhibited by glucocorticoid, such as nuclear factor-kappa B, are also targets for novel anti-inflammatory therapies.
9754553 Fas (CD95)-transduced signal preferentially stimulates lupus peripheral T lymphocytes. 1998 Sep Fas (CD95) is a cell surface receptor whose biological function in circulating peripheral T cells is not well understood. To address the question of abnormal T cell sensitivity to Fas stimulation in systemic lupus erythematosus (SLE), we studied Fas-transduced stimulation and apoptosis in peripheral blood T cells from patients with SLE and normal control. Immobilized anti-Fas monoclonal antibodies (mAb) (imCH-11; IgM type) significantly stimulated SLE T cell proliferation compared to T cells from normal donors and patients with rheumatoid arthritis (p < 0.003 and p < 0.005, respectively). The soluble form of CH-11 and other immobilized anti-Fas mAb (UB-2, ZB-4; IgG type) failed to stimulate lupus T cells while immobilized human Fas ligand did. Furthermore, imCH-11 induced IL-2 and IL-6 mRNA expression. However, imCH-11 activation failed to induce expression of the T cell activation surface molecules CD25 and CD69. Addition of exogenous ceramide, a second messenger for Fas-mediated apoptosis signaling, also induced T cell proliferation in SLE and normal controls. Moreover, fumonisin B1, a specific ceramide synthase inhibitor, and caspase inhibitors markedly suppressed imCH-11 induced T cell proliferation, suggesting that the ceramide pathway may be involved in Fas-transduced stimulation signals in SLE T cells. These results show that SLE T cells have an alteration in the Fas signal transduction pathway leading to cell proliferation. This defect may be important in Fas-mediated peripheral immune homeostasis.
9442926 An increase in the carbohydrate moiety of alpha 2-macroglobulin is associated with systemi 1997 Dec Using lectin blots in conjunction with peptide mapping, alpha 2-macroglobulin micropurified from systemic lupus erythematosus (SLE) patients was shown to become abnormally glycosylated suggesting the occurrence of complex glycosylation in this pathological condition. To confirm there is indeed a quantitative increase in specific monosaccharides in this protein; alpha 2-macroglobulin was micropurified from a battery of 37 serum samples which included 6 normal donors (3 male and 3 female), 23 SLE patients, 6 rheumatoid arthritis patients, 1 mixed connective tissue disease patient, and 1 Sjogren's syndrome patient; for carbohydrate analysis. It was noted that the concentration of total monosaccharides in alpha 2-macroglobulin micropurified from serum samples of SLE patients is significantly higher than normal donors with a mean +/- SD of 188 +/- 410 micrograms/mg protein (SLE, n = 23) versus 14.5 +/- 4 micrograms/mg protein (normal, n = 6) even though there was a high variation in the level of monosaccharides among the SLE patients. An increase in oligosaccharides in alpha 2-macroglobulin from SLE patients compared to normal subjects was confirmed by concanavalin A (Con A) blots using peptide fragments derived from the micropurified protein. Since the interaction of peptide fragments derived from alpha 2-macroglobulin with Con A requires the presence of mannose and/or glucose residues, we have also examined if there are any correlations between the levels of mannose and glucose in alpha 2-macroglobulin and SLE. The concentration of mannose (38 +/- 60 micrograms/mg protein) in alpha 2-macroglobulin derived from SLE patients was significantly higher than normal donors (mannose, 4.8 +/- 1 micrograms/mg protein) however, the concentration of glucose in alpha 2-macroglobulin derived from SLE patients when compared to normal donors was not statistically significant, 18 +/- 20 micrograms/mg protein in SLE versus 2 +/- 0.5 micrograms/mg protein in normal donors due to high variation between samples. Also, the concentration of galactose in alpha 2-macroglobulin from SLE patients was significantly higher than normal donors (45.7 +/- 173 micrograms/mg protein versus 0.13 +/- 0.03 microgram/mg protein). These results illustrate quantification of carbohydrate in selected glycoproteins such as alpha 2-macroglobulin may be a novel and alternative clinical marker for SLE.
9427551 Coding sequence, exon-intron structure and chromosomal localization of murine TNF-stimulat 1997 Nov 20 Tumor necrosis factor stimulated gene-6 (TSG-6) has been previously shown to be induced in vitro in several cell types by proinflammatory cytokines, and in vivo in pathological conditions such as rheumatoid arthritis. In this study, we report the complete coding sequence for the mouse TSG-6 protein, and the exon intron structure and the chromosomal localization of the gene. We have identified a 1605 nt cDNA sequence from mouse cumulus cell oocyte complexes (COCs) induced to expand in vivo. The sequence contains an open reading frame of 825 nt that codes for the 275 amino acid TSG-6 protein. The gene contains six exons separated by 1.1-5.8 kb introns and has been localized to the murine chromosome 2 by linkage analysis. Comparative reverse transcription-polymerase chain reaction studies have revealed that TSG-6 mRNA is specifically expressed after COC expansion induced in vivo, identifying the first non-pathological process in which TSG-6 may play an important role. Since TSG-6 binds to hyaluronan and interacts with inter-alpha-trypsin inhibitor (IalphaI), molecules that are essential for matrix formation by COCs, this protein may have a structural role in the matrix or may enhance the antiproteolytic effect of IalphaI to protect the matrix from degradation.
9422508 The peroxisome proliferator-activated receptor-gamma is a negative regulator of macrophage 1998 Jan 1 The peroxisome proliferator-activated receptor-gamma (PPAR-gamma) is a member of the nuclear receptor superfamily of ligand-dependent transcription factors that is predominantly expressed in adipose tissue, adrenal gland and spleen. PPAR-gamma has been demonstrated to regulate adipocyte differentiation and glucose homeostasis in response to several structurally distinct compounds, including thiazolidinediones and fibrates. Naturally occurring compounds such as fatty acids and the prostaglandin D2 metabolite 15-deoxy-delta prostaglandin J2 (15d-PGJ2) bind to PPAR-gamma and stimulate transcription of target genes. Prostaglandin D2 metabolites have not yet been identified in adipose tissue, but are major products of arachidonic-acid metabolism in macrophages, raising the possibility that they might serve as endogenous PPAR-gamma ligands in this cell type. Here we show that PPAR-gamma is markedly upregulated in activated macrophages and inhibits the expression of the inducible nitric oxide synthase, gelatinase B and scavenger receptor A genes in response to 15d-PGJ2 and synthetic PPAR-gamma ligands. PPAR-gamma inhibits gene expression in part by antagonizing the activities of the transcription factors AP-1, STAT and NF-kappaB. These observations suggest that PPAR-gamma and locally produced prostaglandin D2 metabolites are involved in the regulation of inflammatory responses, and raise the possibility that synthetic PPAR-gamma ligands may be of therapeutic value in human diseases such as atherosclerosis and rheumatoid arthritis in which activated macrophages exert pathogenic effects.
9227169 Methotrexate in patients with moderate systemic lupus erythematosus (exclusion of renal an 1997 Jun OBJECTIVES: Methotrexate (MTX) has been used in several autoimmune diseases. Apart from its use in rheumatoid arthritis, MTX has been assessed in small studies in patients with vasculitis, uveitis, and inflammatory bowel disease. The aim of this study was to evaluate the efficacy of MTX in a particular group of patients with systemic lupus erythematosus (SLE). PATIENTS: In an open prospective study 22 patients fulfilling the ACR criteria for SLE were included. Patients had one or more of the following manifestations; active non-destructive polyarthritis, dermatitis, vasculitis of the skin, pleuritis. All patients had been treated with corticosteroids for at least six months without achieving remission. Sixteen patients were taking antimalarial drugs in addition to corticosteroids, which were stopped at the beginning of the trial. Patients with renal and central nervous involvement were excluded from the study. All patients received MTX orally at a dose of 15 mg/week over six months. Corticosteroids were continued. As additional medication only indomethacin up to 100 mg/day was permitted if used before the start of the study. The outcome was evaluated using the SLE disease activity index (SLEDAI). RESULTS: Disease activity was evaluated after six months of MTX treatment. All patients completed the study period. The SLEDAI decreased significantly from mean (SD) 12.2 (3.99) to 4 (3.75) (p = 0.001). The prednisolone dose was reduced from a mean (SD) of 17.4 (12.8) at the beginning to 8.8 (5.36) mg/day at the end point of the study (p = 0.01). MTX was well tolerated. Four patients complained of general malaise. Two patients had transient increases in liver enzymes. In no case did MTX have to be stopped. CONCLUSIONS: In an open prospective study methotrexate was used in SLE patients with particular clinical characteristics. MTX was shown to be effective in reducing disease activity and sparing the dose of corticosteroids. Further controlled studies are necessary.
9013945 Fc(gamma) receptor cross-linking induces peripheral blood mononuclear cell monocyte chemoa 1997 Feb 1 Immune complexes activate cells by cross-linking leukocyte surface Fc(gamma)Rs. Diseases associated with immune complex deposition, such as rheumatoid arthritis, glomerulonephritis, or idiopathic pulmonary fibrosis, are characterized by compartmentalized monocyte infiltration. The factors that recruit monocytes to these compartments are not well characterized; however, monocyte chemoattractant protein-1 (MCP-1) has been found in areas of tissue injury. To account for these observations we hypothesized that PBMC Fc(gamma)R cross-linking may induce MCP-1 synthesis, which stimulates further monocyte recruitment. To test this hypothesis, PBMC were incubated on increasing concentrations of immobilized human IgG, a stimulus for Fc(gamma)R cross-linking. Immunoreactive MCP-1 was produced in a dose-dependent manner (p < 0.0001). MCP-1 was specifically induced by Fc(gamma)R cross-linking, since immobilized F(ab')2 fragments of human IgG did not activate MCP-1 production. This effect was reproduced by directly cross-linking PBMC Fc(gamma)RIII, but not by cross-linking Fc(gamma)RI or Fc(gamma)RII. PBMC-derived MCP-1 stimulated monocyte chemotaxis that was inhibited by a neutralizing anti-MCP-1 Ab. MCP-1 levels correlated with increased PBMC mRNA expression. Interestingly, Fc(gamma)R cross-linking with either immobilized IgG or anti-Fc(gamma)RIII induced more MCP-1 release from PBMC than from autologous monocytes (p = 0.02). Lymphocytes, the main cell type found in PBMC preparations, did not independently produce a significant amount of MCP-1, but when incubated on immobilized IgG or anti-Fc(gamma)RIII secreted a soluble factor(s) that induced monocyte MCP-1 production. These data suggest that cross-linking PBMC Fc(gamma)R induces the production of bioactive MCP-1. This occurs in part at the level of gene transcription and involves a cooperative interaction between monocytes and lymphocytes.
10616011 Chondroprogenitor cells of synovial tissue. 1999 Dec OBJECTIVE: To assess the chondrogenic potential of cells within the synovium. METHODS: Explants of synovium taken from various sites in the joint were embedded in agarose and cultured with transforming growth factor beta1 (TGFbeta1) to assess their chondrogenic potential. Isolated synovial cells were also tested for their chondrogenic potential by culturing them as aggregates in a chemically defined medium with TGFbeta1. Cartilage formation was determined with histologic staining and immunohistochemistry. The osteochondral potential of the isolated cells was also assessed after subcutaneous implantation of the cells, loaded into porous calcium phosphate ceramic cubes, in athymic mice. RESULTS: A total of 48 synovial explants were cultured in agarose with TGFbeta1. The formation of cartilage was observed in the outer region of 21 explants, and type II collagen was localized in that region by immunohistochemistry. A larger percentage of TGFbeta1+ explants from the inner synovium sites formed cartilage compared with those from the outer synovium sites. Chondrogenesis occurred in aggregates incubated with TGFbeta1 as early as day 7, and by day 14, all TGFbeta1+ aggregates demonstrated chondrogenesis. In contrast with the results of the in vitro aggregate assay for chondrogenesis, no formation of cartilage or bone was evident in any section containing synovial cell-loaded ceramic cubes that were harvested at either 3 or 6 weeks after implantation subcutaneously in athymic mice. CONCLUSION: Synovial explants and isolated synovial cells will undergo chondrogenesis when cultured in the presence of TGFbeta1. The data indicate a possible synovial origin for the chondrocytic cells found in rheumatoid pannus. Furthermore, these data are consistent with the clinical findings of synovial chondrogenesis leading to synovial chondromatosis.
10477582 Role of the costimulatory molecule CD28 in the development of lupus in MRL/lpr mice. 1999 Sep 15 MRL/Mpj-lpr/lpr (MRL/lpr) mice develop autoimmune disorders, including lymphoproliferation, glomerulonephritis, autoantibody production, and hypergammaglobulinemia. To investigate the role of the costimulatory molecule CD28 in the development of these disorders, MRL/lpr mice lacking CD28 were generated by gene targeting. Compared with CD28+/+ MRL/lpr mice, CD28-/- MRL/lpr mice showed decreased lymphadenopathy but increased splenomegaly associated with the expansion of abnormal B220+ TCRalphabeta+ T cells. Although levels of IgM Abs were unchanged in CD28-/- MRL/lpr mice, the production of anti-DNA IgG Abs and IgG rheumatoid factors were suppressed. IgG deposition in the glomeruli was markedly decreased, and the development of glomerulonephritis was significantly retarded. Furthermore, renal vasculitis and arthritis were absent in CD28-/- MRL/lpr mice. These results indicate that, although CD28 is not required for the generation of the abnormal T cell population in MRL/lpr mice, it does play an important role in the development of autoimmune disease in these animals.
11255860 [Extrahepatic manifestations in hepatitis C. Are they overlooked?]. 2001 Feb 10 BACKGROUND: There are accumulating documentation of autoimmune mediated extrahepatic manifestations of hepatitis C virus infection. The virus is hepatotrophic and lymphotrophic. It mutates frequently with subsequent inadequate immune response and chronic stimulation of T and B cells. This may be one explanation for the increased frequency of the autoimmune diseases associated with hepatitis C virus infection. MATERIAL AND METHODS: In this review of the literature published in the period of 1990 to 2000, we present the most common extrahepatic manifestations of the hepatitis C virus infection. RESULTS: Mixed cryoglobulinaemia, membranoproliferative glomerulonephritis and membranous glomerulonephritis are highly associated with hepatitis C infection. Other autoimmune diseases may also be associated with hepatitis C infection, but further documentation is necessary. INTERPRETATION: Extrahepatic manifestations of hepatitis C virus infection are associated with several autoimmune diseases. When diagnosing an autoimmune disease, a test for a coinfection of hepatitis C is highly recommended. Antiviral therapy with interferon may in some cases reduce the activity of the autoimmune disease.
10604234 Retroviruses in autoimmune liver disease: genetic or environmental agents? 1999 Retroviruses have been implicated in the pathogenesis of several human autoimmune conditions including Sjögren's syndrome, primary biliary cirrhosis, immune mediated diabetes, and multiple sclerosis. The human intracisternal A type particle derived from Sjögren's syndrome patients' salivary glands was the first retrovirus to be isolated from a human autoimmune disorder but the agent has yet to be cloned. In primary biliary cirrhosis patients, virus like particles have been observed by electron microscopy in biliary epithelium, endogenous retroviral sequences have been cloned from liver samples, and antibody reactivity to the human intracisternal A type particle has been observed in the majority of patients tested. However, there is no evidence to link the endogenous retroviral sequences in primary biliary cirrhosis patients to the retroviral antibody reactivity or virus like particles. In other patients with liver disease, reactivity to the human intracisternal A type particle was observed in a small but significant proportion of patients with hepatitis C virus infection. If the intracisternal A type particle is an endogenous retrovirus, it is interesting to speculate that hepatitis C virus infection may modulate the endogenous retroviral expression, as chronic hepatitis C has been linked with the development of Sjögren's syndrome. Furthermore, many patients with chronic hepatitis C virus infection have reactivity to an autoantigen of unknown significance known as GOR that has protein sequence homology with both hepatitis C virus nucleocapsid protein as well as HTLV-1 gag. This may be an another example of an endogenous retroviral protein acting as an autoantigen in liver disease patients. At this time, there is little evidence to suggest that endogenous retroviruses are infectious agents that cause autoimmune disease but they may be implicated as either genetic elements or antigens. Further studies will be required to characterize the role that both exogenous and endogenous retroviruses play in the pathogenesis of autoimmune liver diseases.
9858432 Excessive synthesis of matrix metalloproteinases in exocrine tissues of NOD mouse models f 1998 Dec OBJECTIVE: Matrix metalloproteinases (MMP) and their substrates, components of the extracellular matrix, regulate environmental signals for cellular differentiation and tissue function. Changes in the levels of these enzymes may influence cell survival as well as pathology involving ectopic apoptosis. Using the non-obese diabetic (NOD) mouse model for Sjögren's syndrome, we evaluated the synthesis and expression of MMP in the exocrine target tissues of autoimmunity. METHODS: NOD, immunodeficient NOD-scid, and nondiabetic NOD.B10.H2b mice were evaluated for MMP activity in their saliva and exocrine gland lysates by gelatin zymography and reverse transcriptase-polymerase chain reaction (RT-PCR). In addition, changes in protein content of saliva and gland lysates were determined by specific Western blot and by enzymatic activity of amylase and cysteine proteases. Mice continuously treated with the MMP inhibitor GM6001 were evaluated from 7 to 20 weeks of age for the contribution of MMP activity to development of these hallmark biochemical markers of Sjogren's syndrome-like disease of NOD mice. RESULTS: Gelatin zymography of whole saliva and gland lysates indicated the presence of increased proteolytic activity, corresponding to proteins with a molecular mass ranging from 50 to 95 kDa, in the saliva of older (> 20 weeks of age) NOD mice as well as NOD.B10.H2b and NOD-scid mice compared to BALB/c controls. Elevated steady state levels of mRNA transcripts for the gelatinases MMP-2 and MMP-9 were detected in total RNA extracted from parotid and submandibular glands by RT-PCR. Despite prophylactic injection of the broad spectrum MMP inhibitor GM6001 into mice beginning at 7 weeks of age and continuing to 20 weeks, development of the autoimmune exocrinopathy was neither stopped nor retarded. CONCLUSION: These observations suggest that excessive MMP activity is associated with autoimmune Sjögren's syndrome-like disease in NOD mice. However, a possible contribution by increased MMP activity in initiation and progression of this autoimmune disease is yet to be elucidated.
11302869 Glandular and extraglandular expression of costimulatory molecules in patients with Sjögr 2001 May OBJECTIVES: To investigate the expression and regulation of CD80, CD86, and CD28 costimulatory molecules in sialoadenitis and interstitial nephritis in patients with Sjögren's syndrome (SS). METHODS: Expression of CD80, CD86, and CD28 molecules was studied by immunohistochemical staining of lip biopsy specimens obtained from patients who had sialoadenitis associated with SS, and renal biopsy specimens obtained from patients who had interstitial nephritis associated with SS. To elucidate the mechanism of de novo expression of CD80 and CD86 antigens, their induction by cytokines in human salivary duct cell line (HSG) and renal cortical epithelial cells (HRCE) by cell enzyme linked immunosorbent assay (ELISA) was quantitatively investigated. RESULTS: In patients with severe sialoadenitis, CD80 and CD86 were strongly expressed on ductal epithelial cells. In contrast, these antigens were not found in the minor salivary glands of normal subjects or of patients with mild sialoadenitis. Some infiltrating cells expressed CD28. In patients who had interstitial nephritis associated with SS, some tubular epithelial cells expressed CD86 but not the CD80 antigen. Unstimulated HSG cells did not express CD80 or CD86. Interferon gamma (IFNgamma) consistently up regulated levels of CD80 and CD86. In contrast, tumour necrosis factor alpha (TNFalpha), interleukin 1beta (IL1beta), IL2, and IL4 had no effect on either CD80 or CD86 levels. Unstimulated HRCE did not express CD80 or CD86. IFNgamma consistently up regulated CD86 expression. No CD80 expression was found on tubular cells. TNFalpha, IL1beta, IL2, and IL4 had no discernible effects. CONCLUSIONS: Salivary ductal cells in patients with SS can express CD80 and CD86 costimulatory molecules in response to IFNgamma. Tubular epithelial cells in patients who have interstitial nephritis associated with SS express only CD86 molecules. In patients with SS, salivary ductal cells and tubular epithelial cells may activate infiltrating CD28 positive T lymphocytes by presenting antigens to T cells, potentially leading to tissue destruction.
10025916 Expression of B7 costimulatory molecules by salivary gland epithelial cells in patients wi 1999 Feb OBJECTIVE: To investigate the expression of B7 costimulatory molecules in the lymphoepithelial lesions of salivary gland (SG) biopsy tissues and in SG epithelial cell lines derived from patients with Sjögren's syndrome (SS). METHODS: B7.1 and B7.2 protein expression was studied by immunohistochemistry in minor SGs obtained from 11 patients with SS and 10 disease control patients with nonspecific sialadenitis and in cultured SG epithelial cell lines obtained from minor SGs from 15 SS patients and 15 control patients. B7.1 and B7.2 messenger RNA (mRNA) expression by SG epithelial cell lines was examined by reverse transcription-polymerase chain reaction (RT-PCR). RESULTS: In biopsy tissues from SS patients, but not control patients, ductal and acinar epithelial cells showed increased expression of both B7.1 and B7.2. Intense spontaneous B7.1 protein expression (as well as HLA-ABC, but not B7.2 or HLA-DR) was also found in 73% of SG epithelial cell lines from SS patients versus 13% of those from control patients (P < 0.01). Interferon-y treatment induced, or up-regulated, B7.1, B7.2, and HLA-DR expression in all SG epithelial cell lines tested. B7.1 and B7.2 expression by SG epithelial cell lines was also verified at the mRNA level by RT-PCR. CONCLUSION: Human SG epithelia are intrinsically capable of expressing B7 proteins upon activation. In SS patients, the expression of B7 molecules by SG epithelial tissues and by SG epithelial cell lines indicates the activated status of SG epithelial cells in this disorder and, possibly, their capacity for presenting antigens to T cells.