Eosinophilic interleukin 5 (IL-5) transgenic mice: eosinophil activity and impaired clearance of Schistosoma mansoni

Eosinophilia is a feature common to many invasive helminth infections and eosinophils are often considered to be effector cells in immunity to helminths. This study examined the possible influence of constituitive eosinophilia on the clearance of Schistosoma mansoni infections in mice. Eosinophils from interleukin-5 transgenic mice exhibit normal ultrastructure and function with regard to phagocytosis and killing of bacteria and responses to chemotactic stimuli. IL-5 transgenics and non-transgenic littermates were immunized once or four (hyperimmunization) times with irradiated cercariae of S. mansoni . Animals were challenged percutaneously with unirradiated cercariae one month after their last exposure to irradiated parasites. One month after challenge transgenic animals, whether unimmunized, vaccinated or hypervaccinated, carried significantly more liver-stage parasites than non-transgenic animals. These results suggest that although eosinophils from IL-5 transgenic mice are functional for a number of key parameters, large numbers of eosinophils and/or high levels of IL-5 may in some way impair clearance of S. mansoni. A re-evaluation of the roles of eosinophils and IL-5 in infections with this and other parasites may therefore be warranted .     

Interleukin 18 (IL-18) in synergy with IL-2 induces lethal lung injury in mice: a potential role for cytokines, chemokines, and natural killer cells in the pathogenesis of interstitial pneumonia

Interleukin 18 (IL-18) was discovered as an interferon-gamma (IFN-gamma)-inducing factor and plays important roles in natural killer (NK) cell activation. IL-18 also induces proinflammatory cytokines; chemokines; helper T-cell 2 (T(H)2) cytokines (eg, IL-4, IL-13); and immunoglobulin E (Ig-E) and IgG1 production. The combination of IL-18 plus IL-2 or IL-12 up-regulates IFN-gamma gene expression and NK cytotoxicity and has synergistic antitumor activity in vivo and in vitro. Here it is reported that daily administration of IL-18 with IL-2, but not of IL-18 or IL-2 alone, induces lethal lung injury in normal mice, but not in IL-18 receptor alpha (IL-1 receptor-related protein)-deficient (IL-18 receptor alpha(-/-)) mice. Marked interstitial infiltration of lymphocytes, composed mainly of NK cells, was found in the lungs of IL-18/IL-2-treated mice. Increased cytokine and chemokine levels were observed in the sera and lungs of IL-18/IL-2-treated mice. Administration of IL-18/IL-2 was also lethal to mice treated with a metalloproteinase inhibitor, which inhibited tumor necrosis factor-alpha and Fas-ligand release. While IFN-gamma(-/-) mice were partially resistant to the treatment, IL-4(-/-), IL-13(-/-), IL-4/IL-13(-/-), and Stat6(-/-) mice were sensitive to IL-18/IL-2, indicating that these genes were not involved in the host response. The lethal effect by IL-18/IL-2 was completely eliminated in severe combined immunodeficient mice pretreated with antiasialo-GM1 antibody and normal mice pretreated with anti-NK1.1 but not with anti-CD4 or anti-CD8, monoclonal antibody. These results suggest that specific cytokines, chemokines, and NK cells are involved in the pathogenesis of interstitial pneumonia. These results suggest that the clinical use of this interleukin may result in unexpected physiological consequences.     

Hypertonic preconditioning prevents hepatocellular injury following ischemia/reperfusion in mice: a role for interleukin 10

Ischemia/reperfusion (I/R) of the liver occurs in many clinical scenarios including trauma, elective surgery, and transplantation. Events initiated by this process can lead to inflammation in the liver, culminating in local injury as well as distant organ dysfunction. Recent studies have suggested that hypertonic saline exerts anti-inflammatory effects, which may be beneficial in preventing organ injury. In the present study, we examine the effect of hypertonic saline on the development of liver inflammation following I/R in both rat and mouse models. Hypertonic pretreatment was shown to prevent liver enzyme release concomitant with a reduction in liver neutrophil sequestration. Hypertonic saline appeared to exert this effect by inhibiting liver tumor necrosis factor alpha (TNF-alpha) generation, an effect that culminated in reduced liver adhesion molecule expression. Hypertonic saline pretreatment was shown to augment liver interleukin 10 (IL-10) expression following I/R, as a potential mechanism underlying its anti-inflammatory effect. To examine the role of IL-10 in the protective effect of hypertonic saline on liver I/R injury, we used a murine model of I/R. In wild type mice, hypertonic pretreatment similarly prevented liver injury induced by I/R. However, in IL-10 knockout animals, hypertonic pretreatment was unable to prevent the liver enzyme release, TNF-alpha generation, or neutrophil sequestration induced by I/R. In conclusion, these findings define a novel mechanism responsible for the anti-inflammatory effects of hypertonic saline and also suggest a potential clinical role for hyperosmolar solutions in the prevention of liver injury associated with I/R.     

Recovery of hematopoietic colony-forming cells in irradiated mice pretreated with interleukin 1 (IL-1)

Data in this report determined the effect of a single injection of recombinant interleukin 1 alpha (rIL-1) prior to irradiation of B6D2F1 mice on the recovery of colony-forming cells (CFC) at early and late times after sublethal and lethal doses of radiation. Injection of rIL-1 promoted an earlier recovery of mature cells in the blood and CFC in the bone marrow and spleen. For example, 8 days after 6.5 Gy irradiation, the number of CFU-E (colony-forming units-erythroid), BFU-E (burst-forming units-erythroid), and GM-CFC (granulocyte-macrophage colony-forming cells) per femur was approximately 1.5-fold higher in rIL-1-injected mice than in saline-injected mice. Also, 5, 9, and 12 days after irradiation, the number of both day 8 and day 12 CFU-S (colony-forming units-spleen) was almost twofold greater in bone marrow from rIL-1-injected mice. The earlier recovery of CFU-S in rIL-1-injected mice was not associated with an increase in the number of CFU-S that survived immediately after irradiation. Also, 7 months after irradiation, the number of CFU-S per femur of both saline- and rIL-1-injected mice was still less than 50% of normal values. Data in this report demonstrate that a single injection of rIL-1 prior to irradiation accelerates early hematopoietic recovery in irradiated mice, but does not prevent expression of radiation-induced frontend damage or long-term damage to hematopoietic tissues.     

Partial impairment of interleukin-12 (IL-12) and IL-18 signaling in Tyk2-deficient mice

Tyk2 is activated in response to interleukin-12 (IL-12) and is essential for IL-12-induced T-cell function, including interferon-gamma (IFN-gamma) production and Th1 cell differentiation. Because IL-12 is a stimulatory factor for natural killer (NK) cell-mediated cytotoxicity, we examined whether tyk2 is required for IL-12-induced NK cell activity. IL-12-induced NK cell activity in cells from tyk2-deficient mice was drastically reduced compared to that in cells from wild-type mice. IL-18 shares its biologic functions with IL-12. However, the molecular mechanism of IL-18 signaling, which activates an IL-1 receptor-associated kinase and nuclear translocation of nuclear factor-kappaB, is different from that of IL-12. We next examined whether biologic functions induced by IL-18 are affected by the absence of tyk2. NK cell activity and IFN-gamma production induced by IL-18 were reduced by the absence of tyk2. Moreover, the synergistic effect of IL-12 and IL-18 for the production of IFN-gamma was also abrogated by the absence of tyk2. This was partially due to the absence of any up-regulation of the IL-18 receptor treated with IL-12, and it might suggest the presence of the cross-talk between Jak-Stat and mitogen-activated protein kinase pathways in cytokine signaling.     

Reduction of monocrotaline-induced hepatic injury by deleted variant of hepatocyte growth factor (dHGF) in rats

BACKGROUND: Monocrotaline is a hepatotoxic agent which exerts predominant toxicity to central veins and centrilobular sinusoids. In this study, we investigated the effects of deleted variant of hepatocyte growth factor (dHGF) on monocrotaline-induced hepatic injury in rats. METHODS: 100 mg/kg monocrotaline was gavaged to male rats twice with a 4-days' interval. Treatment of dHGF was started 4 days before the initial administration of monocrotaline and 500 microg/kg was intravenously injected twice daily for 11 days. RESULTS: Monocrotaline induced severe damage of central veins and destruction of central zone of hepatic lobules concurrent with derangement of blood levels of total protein, albumin, alanine-aminotransferase, total bilirubin, direct bilirubin, and hepaplastin time. dHGF reduced the structural and blood-chemical abnormalities induced by monocrotaline. CONCLUSIONS: These results suggest that dHGF prevented and repaired the monocrotaline-induced hepatic injury, and could have therapeutic potency in hepatic failure with sever centrilobular destruction.     

Serum gamma-interferon-inducing factor (IL-18) and IL-10 levels in patients with acute hepatitis and fulminant hepatic failure

BACKGROUND AND AIMS: The aim was to determine the role of T-helper (Th)1/Th2 cytokine responses in the clinical outcome of patients with acute liver injury. METHODS: The serum levels of the cytokines, interleukin (IL)-18, gamma-interferon (IFN-gamma), IL-10 and IL-4 were measured in 20 fulminant hepatic failure (FHF), 18 acute hepatitis (AH), 30 chronic viral hepatitis and 20 liver cirrhosis (LC) patients. Thirteen cases were from the intensive care unit (ICU) and there were 21 healthy volunteers. Immunohistochemical staining of liver biopsies for IL-18 expression was also performed. RESULTS: Serum IL-18 levels in patients with FHF were significantly more elevated than in patients with other liver diseases, ICU cases and healthy volunteers. Furthermore, serum IFN-gamma levels in patients with FHF were also significantly higher than in patients with chronic viral hepatitis, LC and healthy volunteers. We found a positive correlation between the levels of IL-18 and IFN-gamma. However, no relationship was observed between these and clinical outcome. In immunohistochemical staining, CD68+ macrophage cells and IL-18-positive cells were observed in portal zones. Elevated serum IL-10 levels were restricted to patients presenting with FHF, and were significantly higher in surviving cases (P < 0.01). Furthermore, serum IL-10 levels, but not IL-4 levels, were inversely correlated with serum total bilirubin concentrations (P = 0.045) and the death rate (p) outlined in Japan (P = 0.030). CONCLUSION: These results suggest that IL-18 and IFN-gamma are involved in the pathogenesis of acute hepatic injury in humans, and that, in particular, elevated serum levels of IL-10 may be predictive of improved outcomes for these patients.     

Serum from patients with fulminant hepatic failure causes hepatocyte detachment and apoptosis by a beta(1)-integrin pathway

Hepatocyte transplantation is restricted by the impaired ability of hepatocytes to engraft and survive in the damaged liver. Understanding the mechanisms that control this process will permit the development of strategies to improve engraftment. We studied changes in liver matrix during acute injury and delineated the mechanisms that perturb the successful adhesion and engraftment of hepatocytes. Collagen IV expression was increased in sinusoidal endothelium and portal tracts of fulminant hepatic failure explants, whereas there were minimal changes in the expression of fibronectin, tenascin, and laminin. Using an in vitro model of cellular adhesion, hepatocytes were cultured on collagen-coated plates and exposed to serum from patients with liver injury to ascertain their subsequent adhesion and survival. There was a rapid, temporally progressive decrease in the adhesive properties of hepatocytes exposed to such serum that occurred within 4 hours of exposure. Loss of activity of the beta1-integrin receptor, which controls adhesion to collagen, was seen to precede this loss of adhesive ability. Addition of the beta1-integrin activating antibody (TS2/16) to cells cultured with liver injury serum significantly increased their adhesion to collagen, and prevented significant apoptosis. In conclusion, we have identified an important mechanism that underpins the failure of infused hepatocytes to engraft and survive in liver injury. Pretreating cells with an activating antibody can improve their engraftment and survival, indicating that serum from patients with liver injury exerts a defined nontoxic biological effect. This finding has important implications in the future of cellular transplantation for liver and other organ diseases.     

Leptin-deficient (ob/ob) mice are protected from T cell-mediated hepatotoxicity: role of tumor necrosis factor alpha and IL-18

The role of leptin was investigated in two models of T cell-mediated hepatitis: the administration of Con A or of Pseudomonas aeruginosa exotoxin A (PEA). In both models, leptin-deficient (ob/ob) mice were protected from liver damage and showed lower induction of tumor necrosis factor (TNF) alpha and IL-18 compared with their lean littermates. Neutralization of TNF-alpha reduced induction of IL-18 by either Con A (70% reduction) or PEA (40% reduction). Pretreatment of lean mice with either soluble TNF receptors or with an anti-IL-18 antiserum significantly reduced Con A- and PEA-induced liver damage. The simultaneous neutralization of TNF-alpha and IL-18 fully protected the mice against liver toxicity. However, neutralization of either IL-18 or TNF-alpha did not inhibit Con A-induced production of IFN-gamma. Thymus atrophy and alterations in the number of circulating lymphocytes and monocytes were observed in ob/ob mice. Exogenous leptin replacement restored the responsiveness of ob/ob mice to Con A and normalized their lymphocyte and monocyte populations. These results demonstrate that leptin deficiency leads to reduced production of TNF-alpha and IL-18 associated with reduced T cell-mediated hepatotoxicity. In addition, both TNF-alpha and IL-18 appear to be essential mediators of T cell-mediated liver injury.     

The hepatic sympathetic nerve plays a critical role in preventing Fas induced liver injury in mice

BACKGROUND: Although previous studies have shown that the hepatic sympathetic nerve controls various physiological functions in the liver, the role of this nerve in liver injury has yet to be clarified. AIMS: The purpose of this study was to elucidate the role of this nerve, based on our newly developed technique for selectively removing the activities of the hepatic sympathetic nerve.Subjects and METHODS: Male C57BL/6 mice were operated on for hepatic sympathetic denervation. Thereafter, mice were intravenously administered 0.25 or 0.35 microg/g weight of the Fas agonist antibody, Jo-2, after which mortality by fulminant hepatitis was evaluated. Apoptosis in the liver was also examined by both terminal deoxynucleotidyl transferase mediated dUTP nick end labelling and caspase-3 assay. RESULTS: Mortality in sympathectomised mice was significantly higher than that in sham operated mice following administration of Jo-2. This result was also supported by apoptosis data in which sympathectomised livers exhibited a significant elevation in the number of apoptotic hepatocytes and caspase-3 activity after Jo-2 treatment compared with sham operated livers. Moreover, pretreatment with norepinephrine dose dependently inhibited the hepatic sympathectomy induced increase in mortality after Jo-2 injection. Antiapoptotic protein levels of FLICE inhibitory protein, Bcl-xL, and Bcl-2 in the liver were significantly lower in sympathectomised mice at one and two hours following Jo-2 treatment than in sham operated animals. In addition, interleukin 6 supplementation dose dependently suppressed the hepatic sympathectomy induced increase in mortality after Jo-2 treatment. CONCLUSIONS: These results suggest that norepinephrine released from the hepatic sympathetic nerve plays a critical role in protecting the liver from Fas mediated fulminant hepatitis, possibly via mechanisms including antiapoptotic proteins and interleukin 6.     

Riboflavin supplementation does not attenuate hyperoxic lung injury in transgenic (spc-mt)hGR mice

The aims of this study were to test the hypothesis that mice expressing mitochondrially targeted human glutathione reductase (GR) driven by a surfactant protein C promoter ((spc-mt)hGR) are functionally riboflavin deficient and that this deficiency exacerbates hyperoxic lung injury. The authors further hypothesized that dietary supplementation with riboflavin (FADH) will improve the bioactivity of GR, thus enhancing resistance to hyperoxic lung injury. Transgenic (mt-spc)hGR mice and their nontransgenic littermates were fed control or riboflavin-supplemented diets upon weaning. At 6 weeks of age the mice were exposed to either room air (RA) or >95% O(2) for up to 84 hours. GR activities (with and without exogenous FADH) and GR protein levels were measured in lung tissue homogenates. Glutathione (GSH) and glutathione disulfide (GSSG) concentrations were assayed to identify changes in GR activity in vivo. Lung injury was assessed by right lung to body weight ratios and bronchoalveolar lavage protein concentrations. The data showed that enhanced GR activity in the mitochondria of lung type II cells does not protect adult mice from hyperoxic lung injury. Furthermore, the addition of riboflavin to the diets of (spc-mt)hGR mice neither enhances GR activities nor offers protection from hyperoxic lung injury. The results indicated that modulation of mitochondrial GR activity in lung type II cells is not an effective therapy to minimize hyperoxic lung injury.     

热休克蛋白70-HBcAg(18～27)蛋白复合物对乙型肝炎病毒转基因小鼠的免疫研究

目的研究结核杆菌热休克蛋白(HSP)70-HBcAg(18～27))蛋白复合物对HBV转基因小鼠免疫应答的影响。方法体外构建HSP70-HBcAg(18～27)蛋白复合物,以HBV转基因小鼠为实验对象,进行体内免疫学功能研究。结果HSP70-HBcAg(18～27)蛋白复合物使HBV转基因小鼠外周血及脾中CD4~ T淋巴细胞和CD8~ T淋巴细胞大量增殖,诱导较强的抗原特异性CTL应答,并活化自然杀伤细胞、树突状细胞参与应答反应。结论HSP70-HBcAg(18～27)蛋白复合物具有免疫原性,能够增强转基因鼠细胞免疫应答能力,有望作为蛋白疫苗用于慢性乙型肝炎的免疫治疗。     

Levels of interleukin (IL)-6, IL-8, and IL-1 receptor antagonist in the hepatic vein following liver surgery

BACKGROUND/AIMS: The liver produces various cytokines, but local changes in the concentrations of these reaction products after liver surgery are unknown. We investigated the local changes of interleukin-6, interleukin-8 and interleukin-1 receptor antagonist after liver surgery. METHODOLOGY: We determined levels of interleukin-6, interleukin-8, and interleukin-1 receptor antagonist in the hepatic vein and radial artery after liver resection in 13 patients. These cytokine levels in the portal vein were also measured in 6 patients. RESULTS: Interleukin-6, interleukin-8, and interleukin-1 receptor antagonist levels were significantly increased during liver surgery (P < 0.05). The level of interleukin-6 was significantly lower in the hepatic vein than in the radial artery as well as in the portal vein at the end of the operation (P < 0.05, < 0.03). The level of interleukin-8 and interleukin-1 receptor antagonist was significantly higher in the hepatic vein than in the artery (P < 0.05). CONCLUSIONS: Interleukin-6 may be taken up by the liver after liver surgery, and the difference between hepatic venous and peripheral arterial interleukin-6 levels may be an indicator of liver regeneration after liver resection. Interleukin-8 and interleukin-1 receptor antagonist appear to be produced in the remaining liver.