transforming-growth-factor-beta and Schistosomiasis-mansoni

Pulmonary arterial hypertension (PAH) is a disease of the lung blood vessels that results in right heart failure. PAH is thought to occur in about 5% to 10% of patients with hepatosplenic schistosomiasis, particularly due to

Topics: Animals; Humans; Lung; Pulmonary Arterial Hypertension; Schistosoma mansoni; Schistosomiasis mansoni; Transforming Growth Factor beta; Vascular Remodeling

Schistosome parasites have co-evolved an intricate relationship with their human and snail hosts as well as a novel interplay between the adult male and female parasites. We review the role of the TGF-beta signaling pathway in parasite development, host-parasite interactions and male-female interactions. The data to date support multiple roles for the TGF-beta signaling pathway throughout schistosome development, in particular, in the tegument which is at the interface with the host and between the male and female schistosome, development of vitelline cells in female worms whose genes and development are regulated by a stimulus from the male schistosome and embryogenesis of the egg. The human ligand TGF-beta1 has been demonstrated to regulate the expression of a schistosome target gene that encodes a gynecophoric canal protein in the schistosome worm itself. Studies on signaling in schistosomes opens a new era for investigation of host-parasite and male-female interactions.

Topics: Animals; Female; Helminth Proteins; Host-Parasite Interactions; Humans; Life Cycle Stages; Ligands; Liver; Male; Protein Serine-Threonine Kinases; Reproduction; Schistosoma mansoni; Schistosomiasis mansoni; Sex Factors; Signal Transduction; Skin; Smad Proteins; Snails; Transforming Growth Factor beta

Transforming growth factor beta (TGF-beta) is an important regulator of inflammation, being proinflammatory at low concentrations and anti-inflammatory at high concentrations. As such, TGF-beta might be important in maintaining the balance between control and clearance of infectious organisms on the one hand and prevention of immune-mediated pathology on the other. In this article, Fakhereldin Omer, Jørgen Kurtzhals and Eleanor Riley review the immunoregulatory properties of TGF-beta in the context of parasitic infections. Data from murine malaria infections suggest that TGF-beta modifies the severity of the disease, and a number of potential protective mechanisms are discussed. Evidence is accumulating that TGF-beta is important for the regulation of other host-parasite interactions and that parasites might directly influence TGF-beta-dependent pathways via the synthesis of TGF-beta or TGF-beta-receptor homologues.

Topics: Animals; Chagas Disease; Genetic Variation; Host-Parasite Interactions; Humans; Leishmaniasis; Malaria; Mice; Mice, Inbred BALB C; Mice, Inbred C57BL; Plasmodium falciparum; Schistosoma mansoni; Schistosomiasis mansoni; Transforming Growth Factor beta; Trypanosoma cruzi

Schistosomiasis mansoni, a major cause of hepatic fibrosis in many developing countries, triggers a granulomatous inflammatory reaction in response to its eggs that lodge in the liver. The egg antigens are eliminated slowly, and the persistent granulomatous response leads to prolonged matrix synthesis and hepatic fibrosis. In mice, soluble egg antigens (SEA) induce interleukin 4 synthesis, promoting a dominant T helper type 2 lymphocyte accumulation with the release of additional cytokines (IL-5, IL-10), which not only suppress Th1 lymphocyte subset cytokines, but mediate the characteristic pathophysiology. Manipulation of the cytokine profile with antagonists or exogenous cytokine delivery alters the course of the hepatic inflammation and fibrosis. In the evolution of the granulomatous response to the S. mansoni eggs, transforming growth factor beta (TGF-beta) is also produced that may modulate inflammation and regulate fibrogenesis. In TGF-beta 1-gene targeted mutant mice that over-express TGF-beta 1 (TGF-beta 1 transgenics) or in which TGF-beta 1 has been inactivated (TGF-beta 1-/-; null mutation) or partially inactivated (TGF-beta 1+/-; null mutation heterozygotes), the altered production of TGF-beta 1 impacts on S. mansoni granuloma and hepatic fibrosis. In addition to the Th1/Th2 cytokine balance, modulation of TGF-beta 1 may change the outcome of chronic inflammatory fibrotic disease.

Topics: Animals; Granuloma; Liver Cirrhosis; Mice; Schistosomiasis mansoni; T-Lymphocytes; Transforming Growth Factor beta

The objective of the present study was to test the hypothesis that treatment of schistosomiasis mansoni with praziquantel can alter significantly the immune response of patients and generate a reversal of the level of fibrosis. Peripheral blood mononuclear cell (PBMC) samples were collected from, and abdominal ultrasound examinations conducted on, volunteers infected with Schistosoma mansoni and living in an area where the disease is endemic, both prior to and one year after treatment with praziquantel. Subjects were classified into groups according to the level of pathology (i.e., absent, incipient, moderate, or severe fibrosis). PBMCs were stimulated with schistosome soluble egg antigens (SEA), and the levels of production of the cytokines gamma interferon (IFN-gamma), tumor necrosis factor alpha, transforming growth factor beta, and interleukin-4 (IL-4), IL-10, and IL-13 were determined. The chemotherapy was effective in reducing morbidity, particularly for individuals presenting with severe fibrosis. When levels of cytokine production in posttreatment PBMC cultures stimulated by SEA were categorized as low or high, significant differences in the distribution of IL-13 levels between groups presenting with or not presenting with fibrosis were established. Comparison of pre- and posttreatment SEA-induced cytokine levels in individuals who had experienced no change in the grade of fibrosis following chemotherapy revealed that the level of IFN-gamma decreased in subjects with fibrosis whereas that of IL-10 decreased in individuals with and without fibrosis. The data suggest that chemotherapy is effective in reducing the morbidity of the disease and that the level of IL-13 may be a useful indicator of the persistence of fibrosis following treatment.

Topics: Adolescent; Adult; Aged; Aged, 80 and over; Animals; Anthelmintics; Brazil; Cytokines; Female; Humans; Interferon-gamma; Interleukin-10; Interleukin-13; Interleukin-4; Leukocytes, Mononuclear; Male; Middle Aged; Praziquantel; Schistosomiasis mansoni; Transforming Growth Factor beta; Ultrasonography; Young Adult

Schistosomiasis is still a major health problem affecting nearly 250 million people worldwide and causes approximately 280,000 deaths per year. The disease causes a serious granulomatous inflammatory response that produces significant mortality. Plumbagin reportedly displays anti-inflammatory, anti-fibrotic, antioxidant and anthelmintic properties. This study further elucidates these properties. Mice were infected with schistosomes and divided into five groups: non-infected untreated (C); infected untreated (IU); non-infected treated with plumbagin (P); infected treated with plumbagin (PI) and infected treated with praziquantel (PZ). Mice treated with 20 mg plumbagin/kg body weight showed reduction of 64.28% and 59.88% in male and female animals, respectively. Also, the number of eggs/g tissue was reduced 69.39%, 68.79% and 69.11% in liver, intestine and liver/intestine combined, respectively. Plumbagin alleviated schistosome-induced hepatosplenomegaly and reduced hepatic granuloma and liver collagen content by 62.5% and 35.26%, respectively while PZQ reduced hepatic granuloma and liver collagen content by 41.11% and 11.21%, respectively. Further, plumbagin treatment significantly (p < .001) reduced IL-4, IL-13, IL-17, IL-37, IFN-γ, TGF-β and TNF-α levels and significantly (p < .001) upregulated IL-10. Plumbagin treatment restored hepatic enzymes activity to nearly normal levels and induced an increase in catalase, SOD, GSH, total thiol and GST in liver tissue homogenate. NO and LPO content was, however, decreased. Moreover, serum IgG levels significantly increased. The present study is the first to report immunomodulatory and schistosomicidal activities of plumbagin in schistosomiasis.

Topics: Animals; Anthelmintics; Anti-Inflammatory Agents; Antioxidants; Catalase; Female; Granuloma; Immunoglobulin G; Interleukin-10; Interleukin-13; Interleukin-17; Interleukin-4; Liver; Male; Mice; Naphthoquinones; Praziquantel; Schistosoma mansoni; Schistosomiasis; Schistosomiasis mansoni; Schistosomicides; Sulfhydryl Compounds; Superoxide Dismutase; Transforming Growth Factor beta; Tumor Necrosis Factor-alpha

Tyrphostin "AG1024" is an insulin growth factor-1 receptor (IGF-1R) inhibitor that displayed an effect on the viability of larval and mature schistosomes in vitro. We sought to investigate the possible in vivo role of AG1024 as a potential new anti-Schistosoma drug against immature and adult stages of Schistosoma mansoni and its effect on the degree of hepatic fibrosis and insulin pathway.. The study included a control non-infected group and 5 groups of S. manosoni-infected CD-1 albino mice (20 mice each) assigned to treatment as follows: vehicle-treated, early AG1024, 30μg/100μl DMSO, IP for 10days started 30days post-infection (dpi), early praziquantel (PZQ), 500mg/kg orally for 2days (30dpi), late AG1024 (60dpi), and late PZQ (60dpi). All mice were sacrificed 12 weeks post-infection. Parasitological, chemical and histopathological parameters were studied. Immunohistochemistry of TGF-β and GLUT4 in liver sections was done to further evaluate the effect of AG1024 on the degree of hepatic fibrosis and insulin signaling pathway, respectively.. Early administration of AG1024 (30dpi) resulted in significant reduction of hepatic and intestinal tissue egg count with a reduction of 79.99% and 89.1% respectively. Late administration of AG1024 (60dpi) led to 77.78% reduction of intestinal eggs count; however, hepatic egg count wasn't reduced significantly. No reduction in worm burden was recorded for both administration regimens. Both regimens lead to significant decrease of both ALT and AST, mean hepatic granuloma diameter but an increase in fibrosis percentage (65.2% and 55% respectively). Both early and late treatment with AG1024 showed a significant increment of TGF-β expression by 71.4% and 39.3%, respectively (p<0.0001) compared to PZQ-treated and infected non-treated groups. Hepatic GLUT4 expression was significantly decreased compared to infected non-treated group (p<0.001) and the corresponding PZQ-treated group.. Early AG1024 administration induced more significant results compared to early PZQ with a promising activity against egg production and subsequent reduction of tissue egg load rather than direct schistosomicidal effect; however, it induced granuloma fibrosis, TGF-β expression, and disrupted the insulin signaling pathway.

Topics: Animals; Antigens, Helminth; Body Weight; Female; Glucose Transporter Type 4; Homeostasis; Insulin Resistance; Liver; Mice; Organ Size; Praziquantel; Receptor, IGF Type 1; Schistosoma mansoni; Schistosomiasis mansoni; Schistosomicides; Transforming Growth Factor beta; Tyrphostins

Hepatic Stellate Cells (HSCs) play a crucial role in pathogenesis of liver inflammation and fibrosis. During chronic liver injury, HSCs lose vitamin A and transform into myofibroblastic cells. In schistosomal granulomas, these activated HSCs are called GR-HSCs. Schistosomal-triggered hepatic fibrogenesis has TGF-β as the most potent fibrogenic stimulus, that also controls gene expression of the angiogenic molecule VEGF in HSCs. COX-dependent production of prostaglandins (PGs) also play role in angiogenic processes. Besides angiogenic roles, prostanoids control immunomodulation of Schistosoma mansoni infection. Specifically, schistosoma-derived PGD2 has emerged as a key parasite regulator of immune defense evasion, while no role is still established to host PGD2. Therefore, the aim of this work is to investigate the ability of GR-HSCs to synthesize COX-derived PGD2 and a potential role of this prostanoid in VEGF production by GR-HSCs in vitro. Here, we confirmed that GR-HSCs express COX-2, which displayed perinuclear localization. While unstimulated GR-HSCs produce basal levels of PGD2, TGF-β stimulation besides increasing COX2- mRNA levels, enhanced synthesis/secretion of PGD2 in GR-HSCs supernatant. Moreover, GR-HSCs-derived PGD2 mediate VEGF production by TGF-β-stimulated GR-HSCs, since the pre-treatment with HQL-79, an inhibitor of hematopoietic PGD synthase inhibited both PGD2 synthesis and VEGF secretion by TGF-β-stimulated GR-HSCs. All together, our findings show an autocrine/paracrine activity of GR-HSCs-derived PGD2 on TGF-β-induced VEGF production by GR-HSCs, unveiling a role for PGD2 as important regulator of HSCs activation in hepatic granulomas from schistosome infected mice.

Topics: Animals; Cell Communication; Cells, Cultured; Cyclooxygenase 2; Granuloma; Hepatic Stellate Cells; In Vitro Techniques; Liver; Male; Mice; Piperidines; Prostaglandin D2; Schistosomiasis mansoni; Transforming Growth Factor beta; Vascular Endothelial Growth Factor A

The etiology of schistosomiasis-associated pulmonary arterial hypertension (PAH), a major cause of PAH worldwide, is poorly understood. Schistosoma mansoni exposure results in prototypical type-2 inflammation. Furthermore, transforming growth factor (TGF)-β signaling is required for experimental pulmonary hypertension (PH) caused by Schistosoma exposure.. We hypothesized type-2 inflammation driven by IL-4 and IL-13 is necessary for Schistosoma-induced TGF-β-dependent vascular remodeling.. Wild-type, IL-4(-/-), IL-13(-/-), and IL-4(-/-)IL-13(-/-) mice (C57BL6/J background) were intraperitoneally sensitized and intravenously challenged with S. mansoni eggs to induce experimental PH. Right ventricular catheterization was then performed, followed by quantitative analysis of the lung tissue. Lung tissue from patients with schistosomiasis-associated and connective tissue disease-associated PAH was also systematically analyzed.. Mice with experimental Schistosoma-induced PH had evidence of increased IL-4 and IL-13 signaling. IL-4(-/-)IL-13(-/-) mice, but not single knockout IL-4(-/-) or IL-13(-/-) mice, were protected from Schistosoma-induced PH, with decreased right ventricular pressures, pulmonary vascular remodeling, and right ventricular hypertrophy. IL-4(-/-)IL-13(-/-) mice had less pulmonary vascular phospho-signal transducer and activator of transcription 6 (STAT6) and phospho-Smad2/3 activity, potentially caused by decreased TGF-β activation by macrophages. In vivo treatment with a STAT6 inhibitor and IL-4(-/-)IL-13(-/-) bone marrow transplantation also protected against Schistosoma-PH. Lung tissue from patients with schistosomiasis-associated and connective tissue disease-associated PAH had evidence of type-2 inflammation.. Combined IL-4 and IL-13 deficiency is required for protection against TGF-β-induced pulmonary vascular disease after Schistosoma exposure, and targeted inhibition of this pathway is a potential novel therapeutic approach for patients with schistosomiasis-associated PAH.

Topics: Animals; Bone Marrow Transplantation; Cell Adhesion Molecules; Humans; Hypertension, Pulmonary; Inflammation; Intercellular Signaling Peptides and Proteins; Interleukin-13; Interleukin-4; Interleukin-4 Receptor alpha Subunit; Macrophages; Mice; Mice, Inbred C57BL; Mice, Knockout; Phosphorylation; Schistosoma mansoni; Schistosomiasis mansoni; Smad2 Protein; Smad3 Protein; STAT6 Transcription Factor; Th1 Cells; Th17 Cells; Transforming Growth Factor beta; Vascular Remodeling

It is suggested that interleukin (IL)-13 and transforming growth factor (TGF)-beta play a role in the pulmonary vascular changes found in animal models of schistosomiasis. The aim of this study was to assess and compare the serum levels of total TGF-beta and IL-13 of patients with schistosomiasis with pulmonary arterial hypertension (PAH) and patients with schistosomiasis without PAH.. 34 patients from the schistosomiasis outpatient clinic of the Hospital das Clinicas, Recife, Pernambuco, Brazil, without PAH assessed by echocardiography and 34 patients from the Reference Centre of Pulmonary Hypertension of Pronto Socorro Cardiológico de Pernambuco, Recife, Brazil with PAH, confirmed by right heart catheterization, were enrolled on the study. Both groups presented with schistosomal periportal fibrosis after abdominal ultrasound. Serum levels of TGF-beta1 and IL-13 were determined by ELISA. Student t test to independent samples, Mann-Whitney test to nonparametric variables, Pearson correlation test for correlation analyses and Fisher Chi-squared test to compare categorical analyses were used.. The median value of TGF-beta1 was significantly higher in patients with PAH (22496.9 pg/ml, interquartile range [IR] 15936.7 - 32087.8) than in patients without PAH (13629.9 pg/ml, IR: 10192.2- 22193.8) (p = 0.006). There was no difference in the median value of IL-13 in the group with Sch-PAH compared to patients without Sch-PAH (p > 0.05).. Our results suggest that TGF-beta possibly plays a role in the pathogenesis of schistosomiasis-associated PAH.

Topics: Adult; Animals; Brazil; Female; Humans; Hypertension, Pulmonary; Interleukin-13; Male; Middle Aged; Schistosomiasis; Schistosomiasis mansoni; Transforming Growth Factor beta; Transforming Growth Factor beta1

Topics: Animals; Humans; Hypertension, Pulmonary; Schistosoma mansoni; Schistosomiasis mansoni; Signal Transduction; Transforming Growth Factor beta

The pathogenic mechanisms underlying pulmonary arterial hypertension resulting from schistosomiasis, one of the most common causes of pulmonary hypertension worldwide, remain unknown. We hypothesized that transforming growth factor-β (TGF-β) signaling as a consequence of Th2 inflammation is critical for the pathogenesis of this disease.. Mice sensitized and subsequently challenged with Schistosoma mansoni eggs developed pulmonary hypertension associated with an increase in right ventricular systolic pressure, thickening of the pulmonary artery media, and right ventricular hypertrophy. Rho-kinase-dependent vasoconstriction accounted for ≈60% of the increase in right ventricular systolic pressure. The pulmonary vascular remodeling and pulmonary hypertension were dependent on increased TGF-β signaling, as pharmacological blockade of the TGF-β ligand and receptor, and mice lacking Smad3 were significantly protected from Schistosoma-induced pulmonary hypertension. Blockade of TGF-β signaling also led to a decrease in interleukin-4 and interleukin-13 concentrations, which drive the Th2 responses characteristic of schistosomiasis lung pathology. Lungs of patients with schistosomiasis-associated pulmonary arterial hypertension have evidence of TGF-β signaling in their remodeled pulmonary arteries.. Experimental S mansoni-induced pulmonary vascular disease relies on canonical TGF-β signaling.

Topics: Animals; Disease Models, Animal; Humans; Hypertension, Pulmonary; Mice; Mice, 129 Strain; Mice, Inbred BALB C; Mice, Inbred C57BL; Mice, Inbred ICR; Mice, Transgenic; Pulmonary Circulation; Schistosoma mansoni; Schistosomiasis mansoni; Signal Transduction; Transforming Growth Factor beta; Vasoconstriction

This study investigates the possible use of pentoxifylline (PTX), with antifibrotic and anti-inflammatory properties, as adjuvant in treatment of schistosomal liver fibrosis through determination of some profibrogenic cytokines, oxidative stress and collagen deposition. Animals were classified into seven groups: normal control (i), Schistosoma mansoni-infected untreated (ii), infected treated with praziquantel (PZQ) curative, 1000mg/kg (iii) or sub curative, 200mg/kg dose (iv), infected treated with PTX alone (10mg/kg/day; 5days/wk) for 8weeks starting from the 2nd to the 10th week post infection (v), or in addition to curative (vi) or sub curative dose of PZQ (vii). Serum transforming growth factor-β1 (TGF-β1), tumor necrosis factor-α (TNF-α), matrix metalloproteinases-2 (MMP-2) and hepatic hydroxyproline (Hyp) content, glutathione related antioxidant enzymes and malondialdehyde (MDA) were determined. Results showed that S. mansoni infection produced remarkable elevations in the serum levels of TGF-β1, TNF-α, MMP-2 and the hepatic contents of Hyp, glutathione reductase (GR), MDA with significant reduction in reduced glutathione (GSH), glutathione peroxidase (GPx), glutathione-S-transferase (GST) and superoxide dismutase (SOD) when compared with their corresponding normal controls. Treatment of infected mice with PTX in addition to PZQ curative rather than its sub curative dose produced the best results evidenced by complete normalization in the previously mentioned serum and hepatic parameters.. PTX could attenuate liver fibrosis in early stages of S. mansoni infection through downregulation of profibrogenic cytokines, oxidative stress and collagen deposition.

Topics: Animals; Collagen; Cytokines; Down-Regulation; Drug Therapy, Combination; Free Radical Scavengers; Hydroxyproline; Lipid Peroxidation; Liver; Male; Matrix Metalloproteinase 2; Mice; Oxidative Stress; Pentoxifylline; Praziquantel; Random Allocation; Schistosomiasis mansoni; Schistosomicides; Transforming Growth Factor beta; Tumor Necrosis Factor-alpha

Schistosomiasis mansoni is a widespread parasitic infection that may lead to several serious complications, such as hepatic periportal fibrosis and portal hypertension, mainly due to deposition of schistosome eggs in the tissues. However, people in endemic areas infrequently exhibit severe pathology and complications; this may be explained, in part, by modulation of the disease in indigenous populations by in utero exposure to the parasite. This study investigated the differences between mice born to Schistosoma mansoni-infected mothers and those born to non-infected ones in subsequent postnatal schistosomal infections. We found that the intensity of infection, evidenced by hepatic egg load, was much reduced in mice born to infected mothers. No difference was found as regards total and Schistosoma-specific immunoglobulin levels except for total IgG. The levels of gene expression of two regulatory cytokines, namely interleukin-12 (IL-12) and transforming growth factor beta (TGF-beta) were found to be significantly increased in prenatally exposed animals. Moreover, liver fibrosis was significantly decreased in animals born to infected mothers as revealed by histopathological and histochemical examination as well as by immunohistochemical identification of activated hepatic stellate cells (HSCs) using antibody against glial fibrillary acidic protein (GFAP). In conclusion, congenital exposure to S. mansoni seems to ameliorate the immunopathological changes in future postnatal infections.

Topics: Animals; Antibodies, Helminth; Antibody Specificity; Female; Glial Fibrillary Acidic Protein; Hepatic Stellate Cells; Immunoglobulin G; Interleukin-12; Liver; Liver Cirrhosis; Maternal-Fetal Exchange; Mice; Pregnancy; Pregnancy Complications, Parasitic; Schistosoma mansoni; Schistosomiasis mansoni; Transforming Growth Factor beta

Eggs of Schistosoma mansoni trapped in human liver can lead to fibrosis. Since liver fibrosis requires activation of hepatic stellate cells (HSC) from a quiescent to a myofibroblastic phenotype, we investigated the effects of S. mansoni eggs on this process using in vitro co-cultures with human HSC and evaluated established biomarkers for activation and fibrosis. HSC demonstrate significantly reduced expression of alpha-smooth muscle actin (p<0.001), connective tissue growth factor (p<0.01) and type I collagen (p<0.001) but significantly increased expression of peroxisome proliferator-activated receptor-gamma (p<0.01). Morphologically, HSC exhibited elongated fine cellular processes and reduced size, increased accumulation of lipid droplets and reduced expression and organization of alpha-smooth muscle actin and F-actin stress fibres. Additionally, schistosome eggs prevented the HSC fibrogenic response to exogenous transforming growth factor-beta. In summary, schistosome eggs blocked fibrogenesis in HSC, a finding which may have implications for our understanding of the fibrotic pathology in S. mansoni infections.

Topics: Animals; Cell Line; Fluorescent Antibody Technique, Indirect; Hepatic Stellate Cells; Host-Parasite Interactions; Humans; Liver; Liver Cirrhosis; Male; Mice; Mice, Inbred C57BL; Microscopy, Phase-Contrast; Phenotype; Polymerase Chain Reaction; PPAR gamma; Schistosoma mansoni; Schistosomiasis mansoni; Transforming Growth Factor beta

We have shown that Schistosoma mansoni egg soluble antigen (SEA) prevents diabetes in the nonobese diabetic (NOD) mouse inducing functional changes in antigen presenting cells (APCs) and expanding T helper (Th) 2 and regulatory T cell (Treg) responses. A Th2 response to S. mansoni infection or its antigens is key to both the establishment of tolerance and successfully reproduction in the host. More recently we demonstrated that SEA treatment upregulates bioactive TGFbeta on T cells with consequent expansion of Foxp3+ Tregs, and these cells might be important in SEA-mediated diabetes prevention together with Th2 cells. In this study we profile further the phenotypic changes that SEA induces on APCs, with particular attention to cytokine expression and markers of macrophage alternative activation. Our studies suggest that TGFbeta from T cells is important not just for Treg expansion but also for the successful Th2 response to SEA, and therefore, for diabetes prevention in the NOD mouse.

Topics: Adaptive Immunity; Animals; Antigens, Helminth; Cell Proliferation; Cytokines; Dendritic Cells; Diabetes Mellitus, Type 1; Female; Forkhead Transcription Factors; Host-Parasite Interactions; Immunity, Innate; Macrophages; Mice; Mice, Inbred NOD; Models, Immunological; Phenotype; Schistosoma mansoni; Schistosomiasis mansoni; Statistics, Nonparametric; T-Lymphocytes, Regulatory; Th2 Cells; Transforming Growth Factor beta

Discovery of the T-helper (Th) 17 cell lineage and functions in immune responses of mouse and man prompted us to investigate the role of transforming growth factor-beta (TGF-beta) and interleukin (IL)-17 in innate resistance to murine schistosomiasis mansoni. Schistosoma mansoni-infected BALB/c and C57BL/6 mice were administered with recombinant TGF-beta or mouse monoclonal antibody to TGF-beta to evaluate the impact of this cytokine on host immune responses against lung-stage schistosomula, and subsequent effects on adult worm parameters. Developing schistosomula elicited increase in peripheral blood mononuclear cells (PBMC) mRNA expression and/or plasma levels of IL-4, IL-17, and interferon-gamma (IFN-gamma), cytokines known to antagonize each other, resulting in impaired Th1/Th2, and Th17 immune responses and parasite evasion. Mice treated with TGF-beta showed elevated PBMC mRNA expression of IL-6, IL-17, TGF-beta, and TNF-alpha mRNA and increased IL-23 and IL-17 or TGF-beta plasma levels, associated with significantly (P<0.02-<0.0001) lower S. mansoni adult worm burden compared to controls in both mouse strains, thus suggesting that TGF-beta led to heightened Th17 responses that mediated resistance to the infection. Mice treated with antibody to TGF-beta showed increase in PBMC mRNA expression and plasma levels of IL-4, IL-12p70, and IFN-gamma, and significantly (P<0.02 and <0.0001) reduced worm burden and liver worm egg counts than untreated mice, indicating that Th1/Th2 immune responses were potentiated, resulting in significant innate resistance to schistosomiasis. The implications of these observations for schistosome immune evasion and vaccination were discussed.

Topics: Animals; Antibodies, Helminth; Cell Lineage; Female; Gene Expression Regulation; Immunity, Innate; Interleukin-17; Mice; Mice, Inbred BALB C; Mice, Inbred C57BL; RNA, Messenger; Schistosomiasis mansoni; T-Lymphocyte Subsets; T-Lymphocytes, Helper-Inducer; Transforming Growth Factor beta

To investigate the potential of bone marrow mononuclear cells (BM-MCs) in the regeneration of hepatic lesions induced by Schistosoma mansoni (S.mansoni) chronic infection.. Female mice chronically infected with S.mansoni were treated with BM-MCs obtained from male green fluorescent protein (GFP) transgenic mice by intravenous or intralobular injections. Control mice received injections of saline in similar conditions. Enzyme-linked immunosorbent assay (ELISA) assay for transforming growth factor-beta (TGF-beta), polymerase chain reaction (PCR) for GFP DNA, immunofluorescence and morphometric studies were performed.. Transplanted GFP(+) cells migrated to granuloma areas and reduced the percentage of liver fibrosis. The presence of donor-derived cells was confirmed by fluorescence in situ hybridization (FISH) analysis for detection of cells bearing Y chromosome and by PCR analysis for detection of GFP DNA. The levels of TGF-beta, a cytokine associated with fibrosis deposition, in liver fragments of mice submitted to therapy were reduced. The number of oval cells in liver sections of S.mansoni-infected mice increased 3-4 fold after transplantation. A partial recovery in albumin expression, which is decreased upon infection with S.mansoni, was found in livers of infected mice after cellular therapy.. In conclusion, transplanted BMCs migrate to and reduce the damage of chronic fibrotic liver lesions caused by S.mansoni.

Topics: Albumins; Animals; Bone Marrow Cells; Bone Marrow Transplantation; Cell Differentiation; Cell Movement; Cell Proliferation; Chronic Disease; Female; Green Fluorescent Proteins; Hepatocytes; Liver; Liver Cirrhosis, Experimental; Liver Regeneration; Male; Mice; Mice, Inbred C57BL; Mice, Transgenic; Schistosoma mansoni; Schistosomiasis mansoni; Transforming Growth Factor beta

The propensity of a range of parasitic helminths to stimulate a Th2 or regulatory cell-biased response has been proposed to reduce the severity of experimental inflammatory bowel disease. We examined whether infection with Schistosoma mansoni, a trematode parasite, altered the susceptibility of mice to colitis induced by dextran sodium sulfate (DSS). Mice infected with schistosome worms were refractory to DSS-induced colitis. Egg-laying schistosome infections or injection of eggs did not render mice resistant to colitis induced by DSS. Schistosome worm infections prevent colitis by a novel mechanism dependent on macrophages, and not by simple modulation of Th2 responses, or via induction of regulatory CD4+ or CD25+ cells, IL-10, or TGF-beta. Infected mice had marked infiltration of macrophages (F4/80+CD11b+CD11c(-)) into the colon lamina propria and protection from DSS-induced colitis was shown to be macrophage dependent. Resistance from colitis was not due to alternatively activated macrophages. Transfer of colon lamina propria F4/80+ macrophages isolated from worm-infected mice induced significant protection from colitis in recipient mice treated with DSS. Therefore, we propose a new mechanism whereby a parasitic worm suppresses DSS-induced colitis via a novel colon-infiltrating macrophage population.

Topics: Animals; Colitis; Dextran Sulfate; Immune Tolerance; Interleukin-10; Macrophages; Mice; Mice, Inbred Strains; Models, Animal; Mucous Membrane; Ovum; Schistosoma mansoni; Schistosomiasis mansoni; T-Lymphocytes, Regulatory; Th2 Cells; Transforming Growth Factor beta

Over 200 million people have, and another 600 million are at risk of contracting, schistosomiasis, one of the major neglected tropical diseases. Transmission of this infection, which is caused by helminth parasites of the genus Schistosoma, depends upon the release of parasite eggs from the human host. However, approximately 50% of eggs produced by schistosomes fail to reach the external environment, but instead become trapped in host tissues where pathological changes caused by the immune responses to secreted egg antigens precipitate disease. Despite the central importance of egg production in transmission and disease, relatively little is understood of the molecular processes underlying the development of this key life stage in schistosomes. Here, we describe a novel parasite-encoded TGF-beta superfamily member, Schistosoma mansoni Inhibin/Activin (SmInAct), which is key to this process. In situ hybridization localizes SmInAct expression to the reproductive tissues of the adult female, and real-time RT-PCR analyses indicate that SmInAct is abundantly expressed in ovipositing females and the eggs they produce. Based on real-time RT-PCR analyses, SmInAct transcription continues, albeit at a reduced level, both in adult worms isolated from single-sex infections, where reproduction is absent, and in parasites from IL-7R(-/-) mice, in which viable egg production is severely compromised. Nevertheless, Western analyses demonstrate that SmInAct protein is undetectable in parasites from single-sex infections and from infections of IL-7R(-/-) mice, suggesting that SmInAct expression is tightly linked to the reproductive potential of the worms. A crucial role for SmInAct in successful embryogenesis is indicated by the finding that RNA interference-mediated knockdown of SmInAct expression in eggs aborts their development. Our results demonstrate that TGF-beta signaling plays a major role in the embryogenesis of a metazoan parasite, and have implications for the development of new strategies for the treatment and prevention of an important and neglected human disease.

Topics: Amino Acid Sequence; Animals; Blotting, Western; Cloning, Molecular; Embryonic Development; Female; Gene Expression Regulation, Developmental; Helminth Proteins; In Situ Hybridization; Male; Mice; Mice, Knockout; Molecular Sequence Data; Rabbits; Reverse Transcriptase Polymerase Chain Reaction; RNA, Small Interfering; Schistosoma mansoni; Schistosomiasis mansoni; Sequence Homology, Amino Acid; Signal Transduction; Transforming Growth Factor beta

Volunteers living in an area where schistosomiasis mansoni is endemic were subjected to ultrasound examination and classified into groups according to the levels of fibrosis diagnosed, namely, absence of indications of fibrosis (group 0), incipient fibrosis (group 1), and moderate/severe fibrosis (group 2). Peripheral blood mononuclear cells (PBMC) collected from the volunteers were stimulated with soluble antigens from adult schistosomes or from schistosome eggs, and the production of the cytokines gamma interferon, tumor necrosis factor alpha, transforming growth factor beta (TGF-beta), interleukin-4 (IL-4), IL-10, and IL-13 was determined. Potential associations of the level of fibrosis with age, sex, intensity of infection, and cytokine production were investigated between the three groups. Univariate analysis identified associations of age (>50), gender (male), and absence of eggs/g of feces with moderate/severe fibrosis and an association of intensity of infection (>100 eggs) with incipient fibrosis. When cytokine production in PBMC cultures stimulated by soluble egg antigens was categorized as low or high, significant differences in the distribution of IL-13 levels were established between groups 0 and 2. No significant differences were detected between the groups in the cytokines produced by PBMC cultures stimulated with soluble antigens from adult schistosomes. When all variables were tested in multivariate analyses, only IL-13 was strongly associated with fibrosis (odds ratio = 5.8; 95% confidence interval [CI] = 1.1 to 30.5). While high levels of TGF-beta appeared to be associated with protection against fibrosis, the strength of the association was low.

Topics: Adolescent; Adult; Aged; Aged, 80 and over; Animals; Cells, Cultured; Chronic Disease; Cytokines; Female; Humans; Interleukin-13; Leukocytes, Mononuclear; Liver Cirrhosis; Liver Diseases, Parasitic; Lymphocyte Activation; Male; Middle Aged; Parasite Egg Count; Portal System; Schistosoma mansoni; Schistosomiasis mansoni; Transforming Growth Factor beta

Schistosomiasis mansoni is a major helminthic disease of the tropics characterised by chronic hepatic and intestinal granulomatous inflammation and fibrosis. The fibrotic response is regulated by the amount of collagen deposited in the tissues and the degradation of that collagen by matrix metalloproteinases (MMP). In the murine model of the disease, although hepatic granuloma formation and the ensuing fibrosis have been thoroughly examined, there is a dearth of information on the intestinal fibrotic process. The expression of fibrosis-related genes in the colons of chronically infected mice has therefore been investigated. Compared with that seen in uninfected mice, the expression of the genes coding for collagen of types I, III and IV was upregulated. Similarly, the messages for MMP-2, MMP-3 and MMP-8 were elevated, indicating the potential for collagen degradation. The genes for two tissue inhibitors of metalloproteinases (TIMP), TIMP-1 and TIMP-4, were, however, expressed at higher levels than those coding for the MMP. As a corollary, expression of the genes coding for three fibrogenic cytokines, transforming growth factor-beta, tumour necrosis factor and interleukin-4, was elevated. These data indicate that an imbalance in MMP:TIMP expression and enhanced levels of the messages for fibrogenic cytokines underlie the mechanism(s) of the colonic fibrosis seen in mice chronically infected with Schistosoma mansoni.

Topics: Animals; Chronic Disease; Collagen; Colon; Colonic Diseases; Cytokines; Disease Models, Animal; Female; Fibrosis; Genes, Helminth; Granuloma; Ileum; Interleukin-4; Matrix Metalloproteinases; Mice; Mice, Inbred CBA; Schistosomiasis mansoni; Tissue Inhibitor of Metalloproteinases; Transforming Growth Factor beta; Tumor Necrosis Factor-alpha; Up-Regulation

Schistosomiasis mansoni disseminated worm eggs in mice and humans induce granulomatous inflammations and cumulative fibrosis causing morbidity and possibly mortality. In this study, intrahepatic and I.V. injections of a double-stranded oligodeoxynucleotide decoy containing the TGF-beta regulatory element found in the distal promoter of the COL1A1 gene into worm-infected mice suppressed TGF-beta1, COL1A1, tissue inhibitor of metalloproteinase-1, and decreased COL3A1 mRNAs to a lesser extent. Sequence comparisons within the mouse genome found homologous sequences within the COL3A1, TGF-beta1, and TIMP-1 5' flanking regions. Cold competition gel mobility shift assays using these homologous sequences with 5' and 3' flanking regions found in the natural COL1A1 gene showed competition. Competitive gel mobility assays in a separate experiment showed no competition using a 5-base mutated or scrambled sequence. Explanted liver granulomas from saline-injected mice incorporated 10.45 +/- 1.7% (3)H-proline into newly synthesized collagen, whereas decoy-treated mice showed no collagen synthesis. Compared with the saline control schistosomiasis mice phosphorothioate double-stranded oligodeoxynucleotide treatment decreased total liver collagen content (i.e. hydroxy-4-proline) by 34%. This novel molecular approach has the potential to be employed as a novel antifibrotic treatment modality.

Topics: Animals; Collagen; Collagen Type I; Collagen Type I, alpha 1 Chain; Consensus Sequence; DNA; Female; Fibroblasts; Granuloma; Hydroxyproline; Liver; Liver Cirrhosis; Liver Diseases; Mice; Mice, Inbred C57BL; Mutation; Myocytes, Smooth Muscle; Oligodeoxyribonucleotides; Oligonucleotides; Schistosomiasis mansoni; Sequence Homology, Nucleic Acid; Signal Transduction; Tissue Inhibitor of Metalloproteinase-1; Transfection; Transforming Growth Factor beta

Fibrosis is a characteristic feature in the pathogenesis of a wide spectrum of diseases. Recently, it was suggested that IL-13-dependent fibrosis develops through a TGF-beta1 and matrix metalloproteinase-9-dependent (MMP-9) mechanism. However, the significance of this pathway in a natural disorder of fibrosis was not investigated. In this study, we examined the role of TGF-beta in IL-13-dependent liver fibrosis caused by Schistosoma mansoni infection. Infected IL-13-/- mice showed an almost complete abrogation of fibrosis despite continued and undiminished production of TGF-beta1. Although MMP-9 activity was implicated in the IL-13 pathway, MMP-9-/- mice displayed no reduction in fibrosis, even when chronically infected. To directly test the requirement for TGF-beta, studies were also performed with neutralizing anti-TGF-beta Abs, soluble antagonists (soluble TGF-betaR-Fc), and Tg mice (Smad3-/- and TGF-betaRII-Fc Tg) that have disruptions in all or part of the TGF-beta signaling cascade. In all cases, fibrosis developed normally and with kinetics similar to wild-type mice. Production of IL-13 was also unaffected. Finally, several genes, including interstitial collagens, several MMPs, and tissue inhibitors of metalloprotease-1 were up-regulated in TGF-beta1-/- mice by IL-13, demonstrating that IL-13 activates the fibrogenic machinery directly. Together, these studies provide unequivocal evidence of a pathway of fibrogenesis that is IL-13 dependent but TGF-beta1 independent, illustrating the importance of targeting IL-13 directly in the treatment of infection-induced fibrosis.

Topics: Animals; Cells, Cultured; Chronic Disease; DNA-Binding Proteins; Extracellular Matrix; Female; Fibrosis; Gene Expression Regulation; Interleukin-13; Liver; Liver Cirrhosis; Matrix Metalloproteinase 9; Mice; Mice, Inbred BALB C; Mice, Inbred C57BL; Mice, Knockout; Schistosomiasis mansoni; Signal Transduction; Smad3 Protein; Trans-Activators; Transforming Growth Factor beta; Transforming Growth Factor beta1; Wound Healing

Controversy persists pertaining to the role of CCR4 ligands, namely CCL17 (or thymus and activation regulated chemokine; TARC) and CCL22 (or macrophage-derived chemokine; MDC), in Th2-type cytokine-dominated responses in the lung. Accordingly, the present study addressed the relative role of each of these CC chemokines during an evolving pulmonary granulomatous response elicited by the intrapulmonary embolization of live Schistosoma mansoni eggs into S. mansoni-sensitized mice. CCL22 protein expression peaked at day 4, but CCL17 levels were not increased significantly at any time after egg challenge. CCR4 transcript and protein expression were highest at day 8 after egg embolization and CCR4 protein was prominently expressed in macrophages surrounding S. mansoni eggs. Systemic immunoneutralization of CCL22 from the time of egg injection into S. mansoni-sensitized mice for 8 days significantly decreased CCR4 protein expression, the eosinophil content, the overall size of the egg granuloma, and its hydroxyproline content. Whole lung levels of interferon-gamma were also significantly increased at day 8 in anti-CCL22-treated mice. The systemic immunoneutralization of CCL17 had a lesser effect on all of the granuloma parameters listed above, but this antibody treatment significantly decreased granuloma hydroxyproline content to a greater extent than the anti-CCL22 antibody treatment. In addition, the immunoneutralization of CCL17 significantly increased whole lung levels of interleukin (IL)-4, IL-5, IL-13, transforming growth factor-beta, IL-12, and tumor necrosis factor-alpha at day 8 after egg infusion. Thus, these studies demonstrate a major role for CCL22 and a lesser role for CCL17 during an evolving S. mansoni egg granuloma in the lung.

Topics: Animals; Chemokine CCL17; Chemokine CCL22; Chemokines, CC; Disease Models, Animal; Enzyme-Linked Immunosorbent Assay; Granuloma, Respiratory Tract; Immunohistochemistry; Interferon-gamma; Interleukins; Lung; Mice; Ovum; Receptors, CCR4; Receptors, Chemokine; Reverse Transcriptase Polymerase Chain Reaction; Schistosoma mansoni; Schistosomiasis mansoni; Transforming Growth Factor beta; Tumor Necrosis Factor-alpha

Leptin, a product of the obese (ob) gene is present in activated stellate cells. This study investigated whether leptin is essential for the development of hepatic fibrosis caused by various agents.. Control and ob/ob mice were infected with Schistosoma mansoni or were administered chronic carbon tetrachloride to cause hepatic fibrosis.. Fibrosis developed in both ob/ob and control mice. However, the amount of histologically detectable fibrosis and the increase in liver hydroxyproline content was significantly greater in both models of fibrosis for treated controls than for treated ob/ob mice. Fibrosis was associated with higher secretion of TGFbeta1 from spleen cells of treated control than treated ob/ob mice. Chronic leptin administration in ob/ob mice infected with Schistosoma mansoni resulted in an increase in the amount of fibrosis caused by Schistosoma mansoni, eliminating any significant differences in the amount of fibrosis between infected ob/ob mice and control mice. It also eliminated any significant difference in TGFbeta1 secretion between the infected ob/ob and infected control mice.. This study shows that leptin deficiency decreases but does not eliminate hepatic fibrosis produced by Schistosoma mansoni and carbon tetrachloride administration. The effect of leptin in potentiating fibrogenesis is most likely mediated by TGFbeta1.

Topics: Animals; Carbon Tetrachloride; Cytokines; Drug Administration Schedule; Leptin; Liver; Liver Cirrhosis, Experimental; Male; Mice; Mice, Inbred C57BL; Mice, Inbred Strains; Obesity; Schistosomiasis mansoni; Spleen; Transforming Growth Factor beta; Transforming Growth Factor beta1

Hepatocellular carcinoma is associated with liver fibrosis. Murine schistosomiasis infection offers a model to study hepatic fibrogenesis. Single-stranded phosphorothiate oligodeoxynucleotides containing the TGF-beta regulatory element have been shown to regulate the transcription of this gene and effectively inhibit collagen synthesis in primary fibroblasts isolated from schistosomiasis-induced hepatic granulomas. While the single-stranded oligos did not decrease collagen and non-collagen protein synthesis below control levels, their double-stranded modified and unmodified counterparts did. Competitive cold oligodeoxynucleotide gel mobility shift analysis using control fibroblast nuclear extract demonstrated that the single-stranded oligos diminished binding of the TGF-beta activator protein to the TGF-beta regulatory element while the double-stranded oligos totally inhibited this binding. TGF-beta element containing single-stranded phosphorothioate oligodeoxynucleotides and their double-stranded counterparts may be successful therapeutic agents to inhibit hepatic fibrogenesis and associated hepatocellular carcinoma.

Topics: Animals; Collagen; Female; Fibroblasts; Granuloma; Liver Cirrhosis; Liver Diseases; Liver Neoplasms; Mice; Mice, Inbred CBA; Oligodeoxyribonucleotides; Rats; Schistosomiasis mansoni; Transforming Growth Factor beta; Wound Healing

In Schistosoma mansoni infection, CD4 T cells specific for parasite egg antigens mediate perioval granuloma formation in the liver and intestines. Mice of the CBA strain develop a severe form of disease and a significant proportion of their CD4 T cell response is directed against the major egg antigen Sm-p40 and its immunodominant T cell epitope peptide 234-246. Here, we show that intranasal (i.n.) treatment of infected CBA mice with a fusion protein of the cholera toxin B subunit (CTB) with peptide 234-246 (CTB::pep) results in significant down-modulation of hepatic granulomatous inflammation and fibrosis. Moreover, egg antigen-stimulated dispersed hepatic granuloma cells, as well as mesenteric lymph node CD4 T cells from the CTB::pep-treated mice, produced significantly more transforming growth factor (TGF)-beta than that produced by treated or untreated controls. The data demonstrate that i.n. administration of a single immunodominant peptide conjugated to CTB can lead to down-regulation of the hepatic immunopathology associated with schistosomiasis, and that this down-regulation is, at least in part, mediated by TGF-beta.

Topics: Administration, Intranasal; Animals; Antigens, Helminth; CD4-Positive T-Lymphocytes; Cholera Toxin; Granuloma; Helminth Proteins; Immunodominant Epitopes; Mice; Mice, Inbred CBA; Peptide Fragments; Schistosoma mansoni; Schistosomiasis mansoni; Snails; Transforming Growth Factor beta

Interleukin-10 (IL-10) and transforming growth factor-beta (TGF-beta) regulate CD4+ T cell interferon-gamma (IFN-gamma) secretion in schistosome granulomas. The role of IL-12 was determined using C57BL/6 and CBA mice. C57BL/6 IL-4-/- granuloma cells were stimulated to produce IFN-gamma when cultured with IL-10 or TGF-beta neutralizing monoclonal antibody. In comparison, C57BL/6 wild-type (WT) control granuloma cells produced less IFN-gamma. IL-12, IL-18, and soluble egg antigen stimulated IFN-gamma release from C57BL/6 IL-4-/- and WT mice. IFN-gamma production in C57 IL-4-/- and WT granulomas was IL-12 dependent, because IL-12 blockade partly abrogated IFN-gamma secretion after stimulation. All granuloma cells released IL-12 (p70 and p40), and IL-12 production remained constant after anti-TGF-beta, anti-IL-10, recombinant IL-18, or antigen stimulation. C57 WT and IL-4-/- mouse granuloma cells expressed IL-12 receptor (IL-12R) beta1-subunit mRNA but little beta2 mRNA. TGF-beta or IL-10 blockade did not influence beta1 or beta2 mRNA expression. CBA mouse dispersed granuloma cells released no measurable IFN-gamma, produced IL-12 p70 and little p40, and expressed IL-12R beta2 and little beta1 mRNA. In T helper 2 (Th2) granulomas of C57BL/6 WT and IL-4-/- mice, cells produce IL-12 (for IFN-gamma production) and IL-10 and TGF-beta modulate IFN-gamma secretion via mechanisms independent of IL-12 and IL-12R mRNA regulation. We found substantial differences in control of granuloma IFN-gamma production and IL-12 circuitry in C57BL/6 and CBA mice.

Topics: Animals; Cells, Cultured; Granuloma, Foreign-Body; Interferon-gamma; Interleukin-10; Interleukin-12; Liver; Mice; Mice, Inbred C57BL; Mice, Inbred CBA; Mice, Knockout; Ovum; Receptors, Interleukin; Receptors, Interleukin-12; Recombinant Proteins; Schistosomiasis mansoni; Spleen; Th2 Cells; Transforming Growth Factor beta

We previously observed that Schistosoma mansoni-infected mice were deficient in their ability to mount a CTL response to unrelated viral antigens and to clear a vaccinia viral infection. Here, we explore the mechanism of that deficiency. Mixing experiments showed that splenocytes from S. mansoni-infected mice actively suppress stimulation in vitro of both viral-peptide specific CTL in spleen cells from virus-infected mice, and allospecific CTL. The mechanism of suppression involves at least in part a soluble factor, in that it can occur across a 0.4-microm membrane which prohibits direct cell contact. However, the inhibition is not alleviated by blocking with antibodies to IL-4, IL-10 or TGF-beta. Fractionation of the splenocyte population from S. mansoni-infected mice shows that the suppression is mediated by a non-B, non-T cell that expresses CD16 and Mac-1, but not FcepsilonR or NK1.1. This represents a novel suppressor population that is distinct from the FcepsilonRI(+) populations of non-B, non-T cells in the spleens of S. mansoni-infected mice that provide a major source of IL-4 in these animals. Similar cells in schistosome-infected humans could affect susceptibility to other infections or responsiveness to vaccines.

Topics: Animals; Antigens; B-Lymphocytes; Cell Adhesion; Female; Humans; Immune Tolerance; Immunophenotyping; Interleukin-10; Interleukin-4; Mice; Mice, Inbred BALB C; Schistosoma mansoni; Schistosomiasis mansoni; Spleen; Suppressor Factors, Immunologic; T-Lymphocytes, Cytotoxic; Transforming Growth Factor beta; Vaccinia virus

Recently, we observed that repeated Schistosoma mansoni infection and treatment boost Th2-associated cytokines and TGF-beta production in baboons. Other studies have shown that some chronically infected baboons develop hepatic fibrosis. Because TGF-beta, IL-2, and IL-4 have been shown to participate in development of fibrosis in murine schistosomiasis, the present study examined whether repeated exposure stimulates hepatic fibrosis in olive baboons. To test this hypothesis, animals were exposed to similar numbers of S. mansoni cercariae given once or repeatedly. After 19 wk of infection, animals were cured with praziquantel and reinfected once or multiple times. Hepatic granulomatous inflammation and fibrosis were assessed from serial liver biopsies taken at weeks 6, 9, and 16 after reinfection and egg Ag (schistosome egg Ag)-specific cytokine production by PBMC were measured simultaneously. Periportal fibroblast infiltration and extracellular matrix deposition (fibrosis), angiogenesis, and biliary duct hyperplasia developed in some animals. The presence and amount of fibrosis directly correlated with the frequency of exposure. Fibrosis was not associated with adult worm or tissue egg burden. The amount of fibrosis correlated with increased schistosome egg Ag-driven TGF-beta at 6, 9, and 16 wk postinfection (rs = 0.9, 0.8, and 0.54, respectively, all p < 0.01) and IL-4 production (p = 0.02) at 16 wk postinfection and not IFN-gamma, IL-2, IL-5, or IL-10. These data suggest that repeated exposure is a risk factor for periportal fibrosis by a mechanism that primes lymphocytes to produce increased levels of profibrotic molecules that include TGF-beta and IL-4.

Topics: Animals; Antigens, Helminth; Dose-Response Relationship, Immunologic; Interleukin-4; Leukocytes, Mononuclear; Liver Cirrhosis, Experimental; Liver Diseases, Parasitic; Male; Ovum; Papio; Risk Factors; Schistosoma mansoni; Schistosomiasis mansoni; Severity of Illness Index; Time Factors; Transforming Growth Factor beta

In an attempt to elucidate further the immunopathological pathways that underlie fibrogenesis induced by Schistosoma mansoni, we have studied the distribution of basement membrane compounds, heparan sulphate proteoglycans (HSPG) and the fibrogenic cytokine transforming growth factor (TGF)-beta in two models of experimental schistosomiasis mansoni (experimental murine infection and synchronous granulomas induced by injection of egg-antigen-coupled beads into the caecal vein). Deposition of the basement membrane proteins type IV collagen, laminin and entactin in schistosomal granulomas was seen 3 days after the implantation of egg-antigen-coupled beads in the liver and persisted over time (32 days). Up-regulation of the membrane-bound HSPG syndecan-1 was observed in the schistosomal granuloma. These syndecan-1-immunoreactive cells represented a distinct subpopulation of granuloma cells; they were different from both mature, unstimulated B-cells (CD40-positive) and endothelial cells (CD105-positive). Deposition of the matrix HSPG perlecan within the granuloma was most prominent 8-16 days after injection. TGF-beta expression was observed in acute (8 weeks) and chronically (13 weeks) infected mice, mainly at the periphery of the schistosomal granuloma and on Kupffer cells in the liver parenchyma. From these observations, we infer that schistosomal fibrosis is composed of various groups of matrix components and that TGF-beta, which is secreted by granuloma cells, is one of the fibrogenic mediators in schistosomal fibrogenesis.

Topics: Animals; Basement Membrane; Fibrosis; Granuloma; Heparan Sulfate Proteoglycans; Liver Diseases, Parasitic; Male; Mice; Schistosomiasis mansoni; Transforming Growth Factor beta

C57BL/6 mice immunized intradermally (i.d.) with bacillus Calmette Guerin (BCG) plus killed skin-stage schistosomula are protected against subsequent infection with Schistosoma mansoni, whereas immunization by i.v. or i.m. routes is not protective. Moreover, previous immunization via the nonprotective i.v. route interfered with the ability to subsequently induce protection by i.d. vaccination, suggesting that inhibitory responses are invoked. Given the evidence that activated macrophages (M phi) play a role as effector cells in protection against schistosomiasis, we investigated the ability of spleen cells from protected and nonprotected immunized mice to produce M phi activating and deactivating cytokines. Exposure to supernatant fluids (SNs) from Ag stimulated spleen cells of i.d., but not i.v. or i.m., immunized mice activated inflammatory M phi for in vitro killing of schistosome larvae, through a mechanism dependent on both IFN gamma and TNF-alpha. No evidence was observed for the preferential induction of the M phi activating Th1 cytokines IFN-gamma and IL-2 in i.d. immunized mice, nor did spleen cells from nonprotected animals produce higher levels of the Th2 associated cytokines IL-4 and IL-10, which are known to prevent M phi activation. TGF-beta was, however, detected in SNs from unprotected mice. Moreover, the M phi inhibitory activity detected in these SNs was heat stable and neutralized by anti-TGF-beta Abs, suggesting that production of TGF-beta is at least partially responsible for the failure of i.m. and i.v. immunized mice to develop immunity to S. mansoni. Thus, the induction of down-regulatory cytokines may be an important factor limiting the efficacy of certain vaccination protocols.

Topics: Animals; BCG Vaccine; Cells, Cultured; Culture Media, Conditioned; Cytokines; Down-Regulation; Female; Injections, Intradermal; Injections, Intramuscular; Injections, Intravenous; Macrophages; Mice; Mice, Inbred C57BL; Schistosomiasis mansoni; Spleen; Th1 Cells; Transforming Growth Factor beta; Vaccination

The study of Schistosoma-induced hepatic fibrosis in murine Schistosoma mansoni infection has elucidated the nature of hepatic fibrosis in humans. In the present study, fibrogenic gene expression was determined in murine S. mansoni infection during primary infection, after chemotherapy with praziquantel, and during secondary infection.. Both histomorphometric analysis and Northern blot profiles were performed.. Histomorphometric analysis of granulomatous inflammation showed smaller hepatic fibrotic granulomata after chemotherapy and during secondary infection. Albumin gene expression remained relatively constant throughout primary infection, chemotherapy, and secondary infection. Fibronectin gene expression in primary infection was comparable with the level observed in noninfected mice and was reduced by chemotherapy. Reinfection resulted in augmented expression levels equal to primary infection levels. Osteonectin gene expression was active in primary infection, was reduced by chemotherapy, and was actively reexpressed in secondary infection. Interstitial matrix macromolecules, types I and III collagen, and basement membrane collagen showed high levels of gene expression in primary infection, were virtually terminated by chemotherapy, and were reexpressed on reinfection. The gene expression of transforming growth factor beta 1, a major, fibrogenic cytokine, paralleled collagen expression.. Chemotherapy of schistosomiasis initiated a dramatic decrease in steady-state messenger RNA levels of major proteins associated with fibrosis; reinfection resulted in a reexpression of these genes.

Topics: Animals; Extracellular Matrix Proteins; Female; Fibrosis; Gene Expression; Liver; Mice; Mice, Inbred Strains; Praziquantel; Schistosomiasis mansoni; Transforming Growth Factor beta