RIBAVIRIN

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POSTERS P123 HGF INDUCES EXPRESSION AND MODULATES TNFa-INDUCED EXPRESSION OF THE CXCR2 LIGANDS CXCL1–3 IN PRIMARY MURINE HEPATOCYTES J. Knievel, D. Ha...

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POSTERS P123 HGF INDUCES EXPRESSION AND MODULATES TNFa-INDUCED EXPRESSION OF THE CXCR2 LIGANDS CXCL1–3 IN PRIMARY MURINE HEPATOCYTES J. Knievel, D. Haussinger, ¨ J.G. Bode. Department of Gastroenterology, Hepatology and Infectious Diseases, University Hospital, HeinrichHeine University, Duesseldorf, Germany E-mail: [email protected] Background and Aims: The functions of the liver are safeguarded by its extraordinary capacity to regenerate. Orchestration of this complex process requires the recruitment of inflammatory cells such as neutrophils and macrophages and the induction of a controlled inflammatory response together with the release of growth factors. Recruitment of the different cell populations and the reestablishment of the functional cellular organization is largely governed by factors such as chemokines, which are key mediators of chemotactic cell movement. The present study analyses the impact of HGF and TNFa on expression and regulation of CXCR2 ligands, which are major chemoatractants for neutrophils, in primary mouse hepatocytes and assesses the impact of hepatocyte-derived chemokines on the migration of neutrophils. Methods: Primary murine hepatocytes were isolated and after respective treatment analyzed by rtPCR and ELISA for chemokine expression. Migration was measured using a 3 mm chemotaxis assay. Results: HGF induces mRNA expression and release of the CXCR2 ligands CXCL1, CXCL2 and CXCL3 in hepatocytes, but not in macrophages and enhances TNFa-induced expression of these chemokines. The induction of all three chemokines requires activation of the PI3-kinase while the regulation downstream of PI3K is specific for each chemokine. Notably, only combined treatment of hepatocytes with both, TNFa and HGF enables hepatocytes to induce migration of neutrophils, which requires activation of CXCR2. Conclusions: These data indicate that in hepatocytes both, TNFa and HGF are required to induce a chemokine response that is able to mediate migratory activity in neutrophils. P124 MATRIX METALLOPROTEINASE (MMP)-DEPENDENT SHEDDING REDUCES NK CELL FcgRIIIa EXPRESSION IN CHRONIC HCV INFECTION WITHOUT AFFECTING THE EFFICIENCY OF ANTIBODY-DEPENDENT CELLULAR CYTOTOXICITY B. Oliviero1 , S. Mantovani1 , A. Zanaboni1 , M.U. Mondelli1,2 . 1 Department of Infectious Diseases, Fondazione IRCCS Policlinico San Matteo, 2 Department of Internal Medicine, University of Pavia, Pavia, Italy E-mail: [email protected] Background and Aims: CD16 (FcgRIIIa) is a potent NK cell activating receptor that mediates Ab-dependent cell-mediated cytotoxicity (ADCC). Reduced NK CD16 expression, leading to impairment of ADCC, has been linked to increased disease severity in chronic viral infections. We evaluated CD16 expression on NK cells in patients with chronic HCV infection (HCVp) to understand regulatory mechanisms and their significance in ADCC efficiency. Methods: NK cell surface CD16 expression and mRNA levels were examined in HCVp (n = 53) and healthy donors (HD, n = 38) by flow cytometry and RT-PCR, respectively. To determine the effects of HCV on CD16 expression, PBMC and purified NK cells were exposed to culture-derived HCV (HCVcc)-infected Huh 7.5 cells before and after MMP inhibition or Galectin (Gal)-9 blockade, both of which are known to modulate CD16 on NK cells. ADCC was evaluated using trastuzumab-coated HER2+ target cells. Results: Ex vivo NK cell CD16 expression and mRNA levels were lower in HCVp compared with HD (p < 0.0001 and p = 0.018, respectively). Following exposure to HCVcc-infected cells, HD

PBMC and purified NK cells significantly down-modulated CD16 (p < 0.001) which was variably influenced by Gal-9 blockade and reproducibly, though not completely, restored by inhibition of MMPs, which regulate CD16 shedding. ADCC was increased in HCVp compared with HD independently of CD16 expression. Conclusions: HCV down-modulates NK CD16 expression in vitro and in vivo predominantly, but not exclusively, via MMP-dependent shedding. Reduced NK CD16 expression had no negative effect on ADCC in HCVp suggesting that the described polarization of NK cells toward cytotoxicity overwhelms reduced FcgRIIIa expression. P125 ROLE OF SIALIC-ACID-BINDING IMMUNOGLOBULIN-LIKE LECTIN-7 (SIGLEC-7) AS BIOMARKER OF LIVER DISEASE SEVERITY IN CHRONIC HCV INFECTION S. Varchetta1 , D. Mele1 , A. Lombardi2 , M.C. Leoni2 , M. Spreafico3 , D. Prati3 , M.U. Mondelli1,2 . 1 Department of Infectious Diseases, Fondazione IRCCS Policlinico San Matteo, 2 Department of Internal Medicine, University of Pavia, Pavia, 3 Department of Transfusion Medicine and Hematology, Ospedale A. Manzoni, Lecco, Italy E-mail: [email protected] Background and Aims: Siglec-7 (S7) is a NK cell inhibitory receptor that recognizes pathogens expressing sialylated surface glycans and is associated with NK phenotypic and functional abnormalities in HIV-1 infection. We asked whether S7 could bind HCV E2 protein and whether NK-expressed and serum S7 (sS7) correlated with clinical parameters and/or identified dysfunctional NK subsets. Methods: S7 binding to HCVE2 was assessed by flow cytometry using a S7 chimeric protein and HCVE2-conjugated beads. NKexpressed and serum S7 were evaluated in patients with chronic HCV infection (HCVp, n = 169) and healthy donors (HD, n = 167) by flow cytometry and ELISA, respectively. Degranulation and cytokine secretion was determined in S7+ and S7− NK cells after co-culture with K562 cells. Results: S7 exhibited strong binding to HCVE2. The proportion of S7-expressing NK was significantly reduced and, conversely, sS7 levels were increased in HCVp compared with HD (p = 0.002 and p < 0.0001, respectively). ROC analysis of sS7 as predictor of HCV infection showed a AUC of 0.84 (95% C.I. 0.80–0.89) with specificity and sensitivity of 82.2% and 78.4% (c/o 1,450 pg/ml). There was a positive correlation between sS7 and serum AST (p < 0.0001), ALT (p = 0.0002) and liver stiffness by transient elastography (p = 0.01) suggesting a role for S7 in liver injury in HCV infection. S7 negative NK cells produced less TNFa in HCVp than in HD (p = 0.03), identifying the existence of a dysfunctional NK subset. Conclusions: HCV binds and modulates S7, likely shed from NK cells in HCVp. Serum S7 emerges as a potentially useful biomarker of liver disease severity in chronic hepatitis C. P126 INCREASED FREQUENCY OF CD8 T CELL RESPONSES TO T CELL APOPTOSIS-DERIVED ANTIGENS IN CHRONICALLY-HCV INFECTED INDIVIDUALS NON-RESPONDING TO PEG-IFNa/RIBAVIRIN H. Martini1 , A. Citro1 , C. Martire1 , D. Accapezzato1 , E.N. Cavallari2 , G. Labbadia1 , G. D’Ettorre2 , V. Vullo2 , V. Barnaba1 . 1 Dipartimento di Medicina Interna e Specialit` a Mediche, 2 Infectious Diseases Department, Sapienza University of Rome, Rome, Italy E-mail: [email protected] Background and Aims: We previously showed that T cell apoptosis determine the generation of caspase-cleaved peptides, which can be cross-presented to specific autoreactive CD8+ T cells. This event participates to immune activation in chronic infections. Here, we investigate the biological role of self-apoptotic-specific-CD8+ T cells in chronic HCV patients treated with Peg-IFNa/Ribavirin. Methods: We enumerate both HCV- and self-apoptotic-CD8+ T cells from PBMCs of patients and donors by MHC-class I

Journal of Hepatology 2014 vol. 60 | S67–S214

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POSTERS dextramers complexed with the relevant peptides. We analyzed cytokine production in dextramer+ CD8+ T cells in response to peptide stimulation by intracellular staining. We characterized dextramer+ CD8+ T cell phenotype with surface and nuclear markers. Results: Patients had higher dextramer+ CD8+ T cell frequencies compared with donors at all times. No difference in dextramer+ CD8+ T cell frequencies was observed at baseline among non-responders (NR), rapid-virological-responders (RVR) and early-virologicalresponders/delayed-virological-responders (EVR/DVR). However, following 4 and 24 weeks of therapy, self-apoptotic-specific CD8+ T cells significantly increased only in NR, whereas they remained stable overtime in EVR/DVR and RVR. IFN-g production by selfapoptotic-CD8+ T cells was lower in NR compared with EVR/DVR and RVR. Conversely, PD1 expression was higher in NR compared with the other groups. The frequency of the self-apoptotic-specific CD8+ T effector memory cells was directly correlated with HCV viral load, whereas self-apoptotic-specific-CD8+ T CD45RA+ effector memory were directly correlated with liver inflammation (Ishak grading). Conclusions: Altogether, these data suggest a possible involvement of self-apoptotic-specific-CD8+ T cells in the progression of chronic HCV infection in NR. P127 CD4+ REGULATORY T CELLS (TREGS) MODULATE INTERACTIONS BETWEEN NK CELLS AND HEPATIC STELLATE CELLS (HSC) IN HEPATITIS C B. Langhans, A.W. Alwan, E.-M. Althausen, B. Kramer, ¨ A. Glassner, ¨ M. Eisenhardt, J. Nattermann, C.P. Strassburg, U. Spengler. Department of Internal Medicine I, University of Bonn, Bonn, Germany E-mail: [email protected] Background and Aims: NK cells regulate liver fibrosis by killing activated hepatic stellate cells (HSC). NK cell function is modified by immune cells and/or soluble factors. In hepatitis C CD4+ regulatory T cells (Tregs) inhibit immune effector cells and also release profibrogenic cytokines such as IL-8. Here, we analyzed if CD4+ Tregs or their cytokines can directly modify the interactions between NK cells and HSC. Methods: NK cells were co-cultured with Tregs from chronic hepatitis C and healthy controls, respectively. NK cell activation was determined by a flowcytometric degranulation assay (CD107a expression). NK cell/HSC interactions were also studied in HSC pretreated with recombinant IL-8, TGF-b1 or IL-10 (0.1–100 ng/ml). Results: Tregs suppressed NK cell activation during HSC co-culture by approximately 30% in a contact-dependent manner, which was blocked by CTLA-4 antibodies (p = 0.0004), but was not mediated by IL-8 or TGF-b1. NK cell degranulation was significantly further reduced in co-cultures with HSC, that had been pre-treated with IL-8 or TGF-b1, as compared to untreated HSC (p < 0.005 each). This additional inhibitory effect corresponded to down-regulation of NK cell activating ligands MIC-A/B (IL-8 exposure) or HLA class I (TGF-b1 exposure) on the pre-treated HSC. Conclusions: Our studies demonstrate that Tregs reduce the cytolytic activity of NK cells against HSC. Recognition of HSC by NK cells is further altered by IL-8 and/or TGF-b1 from Tregs, which down-regulate ligands for activating NK cell receptors on HSC. Thus, Tregs in hepatitis C modify importantly the interactions between NK cells and HSC and alter control of hepatic fibrogenic activity.

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P128 HEPATOCYTES INDUCE A MACROPHAGE PHENOTYPE THAT IS CHARACTERIZED BY EXPRESSION OF A MARKER PROFILE INDICATING M2 MACROPHAGES AND FUNCTIONAL PROPERTIES OF REGULATORY MACROPHAGES S. Wolf, D. Haussinger, ¨ J.G. Bode. Department of Gastroenterology, Hepatology and Infectious Diseases, University Hospital, HeinrichHeine University, D¨ usseldorf, Germany E-mail: [email protected] Background and Aims: Macrophages display a remarkable plasticity enabling them to comply with their different functions. Under homeostatic conditions the liver comprises about 80% of all resident tissue macrophages of the body and it is likely that hepatocytes contribute to the distinctions of these macrophages. This impact of hepatocytes on macrophage differentiation and function probably is mainly mediated via paracrine acting mediators, since these cells are anatomically separated through the sinusoidal endothelial cell layer and the space of Disse. ´ The influence of hepatocytes on macrophages and the underlying communication network is largely unknown and objective of the present study. Methods: A trans-well based co-culture model was developed using highly purified primary murine hepatocytes embedded in a sandwich collagen layer and bone marrow derived macrophages separated by a membrane that allows mediator exchange but no direct cell–cell contact. Results: Evidence is provided that hepatocytes drive macrophage differentiation towards a phenotype characterized by up-regulation of markers such as CD206 indicating so termed wound healing type macrophages but also by properties of regulatory macrophages, which are mainly defined by enhanced IL-10 and decreased IL-12 production in response to LPS. The study further indicates that, although macrophages are required to mediate the main part of the response of hepatocytes towards LPS, hepatocytes are also able to directly respond towards LPS with the expression of a several genes. Conclusions: Hepatocytes and macrophages are subjected to a reciprocal intercellular communication network that defines macrophage differentiation and function as well as the response of hepatocytes towards inflammatory challenges. P129 HEPATITIS C VIRUS MEK1- AND TC-PTP-DEPENDENTLY CONVERTS EPIDERMAL GROWTH FACTOR (EGF) INTO A POTENT INDUCTOR OF CXCR2 LIGAND EXPRESSION 1 1 C. Gropper ¨ , N. Triller1 , S. Eisenburger ¨ , R. Bartenschlager2 , 1 1 1 D. Haussinger ¨ , J.G. Bode . Department of Gastroenterology, Hepatology and Infectious Diseases, University Hospital, HeinrichHeine University, D¨ usseldorf, 2 Department of Infectious Diseases, Molecular Virology, University of Heidelberg, Heidelberg, Germany E-mail: [email protected] Background and Aims: To establish persistent infection the hepatitis C virus (HCV) must have evolved strategies to escape antiviral and innate immunity and to influence the inflammatory response. Since chemokines are important determinants of the constitution of immune cells it is not surprising that during infection HCV engages in the regulation of their expression. However, the interference of HCV with regulation of chemokine expression is incompletely understood. The present study analyses the impact of HCV on the ability of growth factors such as EGF to induce chemokine production in its host cell. Methods: Huh7 cells either infected with the HCV cc strain JC1 or harbouring the HCV1 subgenomic replicon were used and the impact of HCV on cellular signalling and gene expression was investigated employing targeted gene knockdown by siRNA, rtPCR and Immunoblot-analysis.

Journal of Hepatology 2014 vol. 60 | S67–S214