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Glucan phosphate has been shown to enhance antimicrobial immunity in a variety of experimental models. However, the mechanisms by which glucans enhance resistance to infection remain largely unknown. Interferon-gamma (IFN-gamma) is a key regulator of both innate and acquired immunity. Suppression of IFN-gamma production is a prominent feature of the altered immune response that follows major trauma or sepsis. The present studies were designed to determine the effect of glucan phosphate on IFN-gamma expression in normal mice and endotoxin [lipopolysaccharide (LPS)]-tolerant mice. The model of LPS tolerance was used because it results in patterns of cytokine expression similar to those commonly observed following severe trauma or sepsis. Glucan treatment potentiated LPS-induced IFN-gamma expression in control mice. The induction of LPS tolerance resulted in marked suppression of LPS-induced IFN-gamma production. However, co-administration of glucan with LPS, during the tolerance induction phase, attenuated the LPS-tolerant response. Interleukin-12 (IL-12) and IL-18 are important mediators of LPS-induced IFN-gamma production. LPS-induced IL-12 p40 mRNA expression was increased in the spleens of glucan-treated mice compared with controls. Induction of LPS tolerance caused marked suppression of IL-12 production, a response that was attenuated by glucan treatment. IL-18 was constitutively expressed in both control and LPS-tolerant mice, and LPS-induced serum levels of IL-18 were increased in mice treated with glucan. T cells isolated from glucan-treated mice exhibited increased IFN-gamma expression in response to IL-12 and IL-18, as well as increased expression of the IL-12 and IL-18 receptors. The ability of glucan to potentiate IFN-gamma expression in control mice provides a potential mechanism by which glucan enhances antimicrobial immunity. The ability of glucan to attenuate suppressed IFN-gamma expression in LPS-tolerant mice denotes its potential benefit for the treatment of trauma and sepsis-induced immunosuppression.

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Endotoxin (lipopolysaccharide [LPS]) tolerance is a state of altered immunity characterized, in part, by suppression of LPS-induced gamma interferon (IFN-gamma) expression. However, the cellular mediators regulating LPS-induced production of IFN-gamma in normal mice and the effect of LPS tolerance on these mediators has not been well characterized. Our studies show that macrophage dysfunction is the primary factor causing suppressed IFN-gamma expression in LPS-tolerant mice. Specifically, LPS-tolerant macrophages have a markedly impaired ability to induce IFN-gamma secretion by T cells and NK cells obtained from either control or LPS-tolerant mice. However, T cells and NK cells isolated from LPS-tolerant mice produce normal levels of IFN-gamma when cocultured with control macrophages or exogenous IFN-gamma-inducing factors. Assessment of important IFN-gamma-regulating factors showed that interleukin-12 (IL-12) and costimulatory signals provided by IL-15, IL-18, and CD86 are largely responsible for LPS-induced IFN-gamma expression in control mice. IL-10 is an inhibitor of IFN-gamma production in both the control and LPS-tolerant groups. Expression of IL-12 and the IL-12 receptor beta1 (IL-12Rbeta1) and IL-12Rbeta2 subunits are suppressed in the spleens of LPS-tolerant mice. LPS-tolerant splenocytes also exhibit decreased production of IL-15 and IL-15Ralpha. However, expression of IL-18 and the B7 proteins CD80 and CD86 are unchanged or increased compared to controls after induction of LPS tolerance. CD28, a major receptor for B7 proteins, is also increased in the spleens of LPS-tolerant mice. Expression of the inhibitory cytokine IL-10 and the IL-10R are sustained after induction of LPS tolerance. These data show that suppression of IFN-gamma production in LPS-tolerant mice is largely due to macrophage dysfunction and provide insight into the cellular alterations that occur in LPS tolerance. This study also better defines the factors that mediate LPS-induced IFN-gamma production in normal mice.

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An ion-exchange chromatographic fraction of Taenia hydatigena metacestode was evaluated for use in the immunodiagnosis of ovine cysticercosis. Analysis of the fraction by sodium dodecyl sulphate--polyacrylamide gel electrophoresis revealed the presence of a 68 KDa protein. Antibodies against the isolated protein were detected in 7 out of 10 experimentally infected lambs. The diagnostic potential of the 68 KDa protein was further confirmed by testing sera from naturally infected post-mortem positive (PM+) and from apparently healthy groups of animals. Eighty % and 8% of animals were found positive by enzyme-linked immunosorbent assay (ELISA) in the groups of PM+ and apparently non-infected lambs, respectively.

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Subsequent to the binding of insulin to the insulin receptor (IR), present at the cell surface of all the tissues studied so far, conformational change in IR leads to the activation of IR tyrosine kinase. However, the transducer of the signal from IR to its effector(s) is poorly understood, at best. Although GTP-binding proteins (G-proteins) have been implicated in insulin's metabolic actions, a G-protein that directly interacts with IR has not been identified. In the present study, a novel 66 kDa GTP-binding protein, Gir, has been isolated and characterized. IR and Gir from human placental membrane bound to insulin-Sepharose column. GTP as well as GDP (1 mM) eluted Gir from the column and acetate buffer (pH 5.0) eluted both IR and Gir. Both IR and Gir, thus eluted, absorbed on the anti-IR-Sepharose column and GTP eluted Gir. Antibodies against synthetic peptides from GTP-binding and ADP-ribosylation domains of Gz alpha and Gi-3 alpha, respectively, cross-reacted with Gir at various stages of purification. Insulin-activated IR tyrosine kinase phosphorylated Gir which was immunoprecipitated by both the antisera. These studies indicate that IR is complexed with Gir, which could be one of the G-proteins implicated in insulin's signal transduction.

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A novel 66 kDa GTP-binding protein, designated Gir, has been partially purified along with insulin receptor (IR) from human placenta. This protein binds 8-azido-GTP, is ADP-ribosylated by pertussis toxin, phosphorylated by IR tyrosine kinase and cross-reacts with antibodies against synthetic peptides from the GTP-binding domain of Gz alpha(P960). Phosphorylation of IR-beta subunit and Gir by IR tyrosine kinase was almost completely inhibited by 100 microM GTP gamma S, > 75% by 50 microM and 20-30% by 1 microM, while GDP at these concentrations had no significant effect on the phosphorylation. IR tyrosine kinase phosphorylated Gir at the tyrosine residues. These studies indicate regulation of IR tyrosine kinase activity by guanosine phosphates and involvement of Gir in insulin action.

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A 66 kDa GTP-binding protein, Gir, and insulin receptor (IR) were copurified from human placental membrane by DEAE-Sephacel and Wheat Germ Agglutinin (WGA)-Sepharose affinity chromatography. The WGA-fraction containing IR and Gir (IR-Gir-fraction) was phosphorylated (95 kDa IR-beta and 66 kDa Gir) by IR-tyrosine kinase using [32P]ATP or photolabeled with [32P]8-azido-GTP (mainly 66 kDa), and was cross-linked with a bifunctional reagent, bis-[sulfosuccinimidyl] suberate (BS3). The Gir cross-linked with putative subunit(s) to form a 110 kDa complex. Phosphorylation as well as 8-azido-GTP binding to Gir was not affected by cross-linking indicating that like other G-Proteins, Gir may also have subunits and that cross-linking of Gir with its putative subunits(s) does not block GTP-binding and phosphorylation sites.

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The efficacy of Mebendazole and Niclosamide was studied in two groups of 24 and 38 cases, respectively of patients suffering from taeniasis. Mebendazole with dose schedule of 200 and 300 mg twice daily for 3 consecutive days showed a cure rate of 71.42% and 92.30%, whereas Niclosamide at the dose rate of 200mg per patient was 94.76% effective. Flubendazole showed a cure rate of 66.66% only. Mebendazole and Niclosamide possess high taeniacidal activity, ability to reduce the clinical symptoms of taeniasis without any side effects. Niclosamide with high activity and excellent tolerance, is a drug of choice for the treatment of taeniasis in single dose treatment while for hymenolepsiasis it needs extended course.

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The possibility of safe immunization of chicks at an appropriate age with a double-dose irradiated Ascaridia galli vaccine given orally at two weeks interval was explored. Chicks immunized at 7 or 10 days of age were not affected adversely since they did not develop any clinical signs and there was no worm establishment after challenge infection. Immunization also elicited detectable circulating antibody titres, with IHA and the conglutinating complement absorption test having a tendency to be enhanced after the booster dose.

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Growth and cell-mediated immune (CMI) responses were studied in 7-day-old chicks given orally 1000 irradiated (12.5 kR) or normal infective eggs of Ascaridia galli. Chicks immunised with irradiated eggs showed normal weight gains. CMI responses, as assessed by dinitrofluorobenzene (DNFB)-induced contact and delayed hypersensitivity reactions, were enhanced in the immunised group as compared with healthy controls, suggesting stimulation of CMI responses due to irradiation of A. galli eggs. CMI as well as growth responses were, however, found to be depressed in the birds administered normal infective eggs of A. galli. The present study highlights the role of the CMI response in protection against A. galli infection.

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