Sonja Ortler

Publications of Sonja Ortler

• The role of dendritic cells in CNS autoimmunity.

  Authors: Alla L Zozulya, Benjamin D Clarkson, Sonja Ortler, Zsuzsanna Fabry, Heinz Wiendl

  Journal of molecular medicine (Berlin, Germany). 03/2010; 88(6):535-44.

  Multiple sclerosis (MS) is a chronic immune-mediated, central nervous system (CNS) demyelinating disease. Clinical and histopathological features suggest an inflammatory etiology involving residentMultiple sclerosis (MS) is a chronic immune-mediated, central nervous system (CNS) demyelinating disease. Clinical and histopathological features suggest an inflammatory etiology involving resident CNS innate cells as well as invading adaptive immune cells. Encephalitogenic myelin-reactive T cells have been implicated in the initiation of an inflammatory cascade, eventually resulting in demyelination and axonal damage (the histological hallmarks of MS). Dendritic cells (DC) have recently emerged as key modulators of this immunopathological cascade, as supported by studies in humans and experimental disease models. In one such model, experimental autoimmune encephalomyelitis (EAE), CNS microvessel-associated DC have been shown to be essential for local antigen recognition by myelin-reactive T cells. Moreover, the functional state and compartmental distribution of DC derived from CNS and associated lymphatics seem to be limiting factors in both the induction and effector phases of EAE. Moreover, DC modulate and balance the recruitment of encephalitogenic and regulatory T cells into CNS tissue. This capacity is critically influenced by DC surface expression of co-stimulatory or co-inhibitory molecules. The fact that DC accumulate in the CNS before T cells and can direct T-cell responses suggests that they are key determinants of CNS autoimmune outcomes. Here we provide a comprehensive review of recent advances in our understanding of CNS-derived DC and their relevance to neuroinflammation.

• Deficiency of the negative immune regulator B7-H1 enhances inflammation and neuropathic pain after chronic constriction injury of mouse sciatic nerve.

  Authors: Nurcan Uçeyler, Kerstin Göbel, Sven G Meuth, Sonja Ortler, Guido Stoll, Claudia Sommer, Heinz Wiendl, Christoph Kleinschnitz

  Experimental neurology. 03/2010; 222(1):153-60.

  Peripheral nerve injury induces a profound local inflammatory response that involves T cells and macrophages and augments the generation of neuropathic pain. The mechanisms underlying immune cellPeripheral nerve injury induces a profound local inflammatory response that involves T cells and macrophages and augments the generation of neuropathic pain. The mechanisms underlying immune cell activation or inhibition in the peripheral nervous system, however, are unknown. The co-inhibitory molecule B7-H1 (PD-L1, CD274) attenuates immune cell proliferation and cytokine production and protects from inflammation-induced tissue damage. We analyzed the temporal gene expression profile of B7-H1 and different cytokines after chronic constriction injury (CCI) of the sciatic nerve, a lesion paradigm inducing neuropathic pain, by quantitative real-time polymerase chain reaction and immunohistochemistry in B7-H1(-/-) mice and wild-type (WT) controls. B7-H1 mRNA was markedly induced in WT nerves after CCI, and macrophages could be identified as major B7-H1 source. The proinflammatory mediators tumor necrosis factor alpha (TNFalpha) and monocyte chemoattractant protein-1 (MCP-1) displayed a strong, but transient expression in degenerating nerves on day 1 after CCI in WT mice, while a biphasic expression peak on day 1 and day 28 was found in B7-H1(-/-) mice. Overall, TNFalpha and MCP-1 levels in B7-H1-deficient nerves dramatically exceeded those in WT controls. In contrast, induction of the anti-inflammatory cytokine interleukin(IL)-10 was restricted to WT nerves. The observation that B7-H1 deficiency enhances inflammation upon CCI was further corroborated by immunohistochemistry showing increased numbers of T cells and macrophages in injured nerves from B7-H1(-/-) mice. Interestingly, mechanical hyperalgesia was more pronounced in the absence of B7-H1. Our study identifies B7-H1 as an important suppressor of the inflammatory response and neuropathic pain occurring after peripheral nerve injury.

• B7-H1-deficiency enhances the potential of tolerogenic dendritic cells by activating CD1d-restricted type II NKT cells.

  Authors: Carolin Brandl, Sonja Ortler, Thomas Herrmann, Susanna Cardell, Manfred B Lutz, Heinz Wiendl

  PloS one. 01/2010; 5(5):e10800.

  Dendritic cells (DC) can act tolerogenic at a semi-mature stage by induction of protective CD4(+) T cell and NKT cell responses. Here we studied the role of the co-inhibitory molecule B7-H1 (PD-L1,Dendritic cells (DC) can act tolerogenic at a semi-mature stage by induction of protective CD4(+) T cell and NKT cell responses. Here we studied the role of the co-inhibitory molecule B7-H1 (PD-L1, CD274) on semi-mature DC that were generated from bone marrow (BM) cells of B7-H1(-/-) mice and applied to the model of Experimental Autoimmune Encephalomyelitis (EAE). Injections of B7-H1-deficient DC showed increased EAE protection as compared to wild type (WT)-DC. Injections of B7-H1(-/-) TNF-DC induced higher release of peptide-specific IL-10 and IL-13 after restimulation in vitro together with elevated serum cytokines IL-4 and IL-13 produced by NKT cells, and reduced IL-17 and IFN-gamma production in the CNS. Experiments in CD1d(-/-) and Jalpha281(-/-) mice as well as with type I and II NKT cell lines indicated that only type II NKT cells but not type I NKT cells (invariant NKT cells) could be stimulated by an endogenous CD1d-ligand on DC and were responsible for the increased serum cytokine production in the absence of B7-H1. Together, our data indicate that BM-DC express an endogenous CD1d ligand and B7-H1 to ihibit type II but not type I NKT cells. In the absence of B7-H1 on these DC their tolerogenic potential to stimulate tolerogenic CD4(+) and NKT cell responses is enhanced.

• Accelerated Course of Experimental Autoimmune Encephalomyelitis in PD-1-Deficient Central Nervous System Myelin Mutants.

  Authors: Antje Kroner, Nicholas Schwab, Chi Wang Ip, Sonja Ortler, Kerstin Göbel, Klaus-Armin Nave, Mathias Mäurer, Rudolf Martini, Heinz Wiendl

  The American journal of pathology. 06/2009;

  It is assumed that the onset and course of autoimmune inflammatory central nervous system (CNS) disorders (eg, multiple sclerosis) are influenced by factors that afflict immune regulation as well asIt is assumed that the onset and course of autoimmune inflammatory central nervous system (CNS) disorders (eg, multiple sclerosis) are influenced by factors that afflict immune regulation as well as CNS vulnerability. We challenged this concept experimentally by investigating how genetic alterations that affect myelin (primary oligodendrocyte damage in PLPtg mice) and/or T-cell regulation (deficiency of PD-1) influence both the onset and course of an experimental autoimmune CNS inflammatory disease [MOG35-55-induced experimental autoimmune encephalomyelitis (EAE)]. We observed that double pathology was associated with a significantly earlier onset of disease, a slight increase in the neurological score, an increase in the number of infiltrating cells, and enhanced axonal degeneration compared with wild-type mice and the respective, single mutant controls. Double-mutant PLPtg/PD-1(-/-) mice showed an increased production of interferon-gamma by CNS immune cells at the peak of disease. Neither PD-1 deficiency nor oligodendropathy led to detectable spread of antigenic MHC class I- or class II-restricted epitopes during EAE. However, absence of PD-1 clearly increased the propensity of T lymphocytes to expand, and the number of clonal expansions reliably reflected the severity of the EAE disease course. Our data show that the interplay between immune dysregulation and myelinopathy results in a stable exacerbation of actively induced autoimmune CNS inflammation, suggesting that the combination of several pathological issues contributes significantly to disease susceptibility or relapses in human disease.

• The level of B7 homologue 1 expression on brain DC is decisive for CD8 Treg cell recruitment into the CNS during EAE.

  Authors: Alla L Zozulya, Sonja Ortler, Zsuzsanna Fabry, Matyas Sandor, Heinz Wiendl

  European journal of immunology. 06/2009;

  DC in the CNS have emerged as the major rate-limiting factor for immune invasion and subsequent neuroinflammation during EAE. The mechanism of how this is regulated by brain-localized DC remainsDC in the CNS have emerged as the major rate-limiting factor for immune invasion and subsequent neuroinflammation during EAE. The mechanism of how this is regulated by brain-localized DC remains unknown. Here, we describe the ability of brain-localized DC expressing B7-H1 molecules to recruit CD8(+) T cells to the site of inflammation. Using intracerebral microinjections of B7-homologue 1-deficient DC(,) we demonstrate a substantial brain infiltration of CD8(+) T cells displaying a regulatory phenotype (CD122(+)) and function, resulting in a decrease of EAE peak clinical values. The recruitment of regulatory-type CD8(+) T cells into the CNS and the role of brain DC expressing B7-homologue 1 molecules in this process open up the possibility of DC-targeted therapeutic manipulation of neuroinflammatory diseases.

• Intracerebral dendritic cells critically modulate encephalitogenic versus regulatory immune responses in the CNS.

  Authors: Alla L Zozulya, Sonja Ortler, Jangeun Lee, Christian Weidenfeller, Matyas Sandor, Heinz Wiendl, Zsuzsanna Fabry

  The Journal of neuroscience : the official journal of the Society for Neuroscience. 02/2009; 29(1):140-52.

  Dendritic cells (DCs) appear in higher numbers within the CNS as a consequence of inflammation associated with autoimmune disorders, such as multiple sclerosis, but the contribution of these cells toDendritic cells (DCs) appear in higher numbers within the CNS as a consequence of inflammation associated with autoimmune disorders, such as multiple sclerosis, but the contribution of these cells to the outcome of disease is not yet clear. Here, we show that stimulatory or tolerogenic functional states of intracerebral DCs regulate the systemic activation of neuroantigen-specific T cells, the recruitment of these cells into the CNS and the onset and progression of experimental autoimmune encephalomyelitis (EAE). Intracerebral microinjection of stimulatory DCs exacerbated the onset and clinical course of EAE, accompanied with an early T-cell infiltration and a decreased proportion of regulatory FoxP3-expressing cells in the brain. In contrast, the intracerebral microinjection of DCs modified by tumor necrosis factor alpha induced their tolerogenic functional state and delayed or prevented EAE onset. This triggered the generation of interleukin 10 (IL-10)-producing neuroantigen-specific lymphocytes in the periphery and restricted IL-17 production in the CNS. Our findings suggest that DCs are a rate-limiting factor for neuroinflammation.

• B7-H1 restricts neuroantigen-specific T cell responses and confines inflammatory CNS damage: implications for the lesion pathogenesis of multiple sclerosis.

  Authors: Sonja Ortler, Christoph Leder, Michel Mittelbronn, Alla L Zozulya, Percy A Knolle, Lieping Chen, Antje Kroner, Heinz Wiendl

  European journal of immunology. 07/2008; 38(6):1734-44.

  The co-inhibitory B7-homologue 1 (B7-H1/PD-L1) influences adaptive immune responses and has been proposed to contribute to the mechanisms maintaining peripheral tolerance and limiting inflammatoryThe co-inhibitory B7-homologue 1 (B7-H1/PD-L1) influences adaptive immune responses and has been proposed to contribute to the mechanisms maintaining peripheral tolerance and limiting inflammatory damage in parenchymal organs. To understand the B7-H1/PD1 pathway in CNS inflammation, we analyzed adaptive immune responses in myelin oligodendrocyte glycoprotein (MOG)(35-55)-induced EAE and assessed the expression of B7-H1 in human CNS tissue. B7-H1(-/-) mice exhibited an accelerated disease onset and significantly exacerbated EAE severity, although absence of B7-H1 had no influence on MOG antibody production. Peripheral MOG-specific IFN-gamma/IL-17 T cell responses occurred earlier and enhanced in B7-H1(-/-) mice, but ceased more rapidly. In the CNS, however, significantly higher numbers of activated neuroantigen-specific T cells persisted during all stages of EAE. Experiments showing a direct inhibitory role of APC-derived B7-H1 on the activation of MOG-specific effector cells support the assumption that parenchymal B7-H1 is pivotal for delineating T cell fate in the target organ. Compatible with this concept, our data investigating human brain tissue specimens show a strong up-regulation of B7-H1 in lesions of multiple sclerosis. Our findings demonstrate the critical importance of B7-H1 as an immune-inhibitory molecule capable of down-regulating T cell responses thus contributing to the confinement of immunopathological damage.

• Modulation of T-effector function by imatinib at the level of cytokine secretion.

  Authors: Christoph Leder, Sonja Ortler, Ruth Seggewiss, Hermann Einsele, Heinz Wiendl

  Experimental hematology. 09/2007; 35(8):1266-71.

  OBJECTIVE: Recently, evidence was provided, that the selective tyrosine kinase inhibitor imatinib mesylate (imatinib) has immunomodulatory or suppressive effects. However, the discussion aboutOBJECTIVE: Recently, evidence was provided, that the selective tyrosine kinase inhibitor imatinib mesylate (imatinib) has immunomodulatory or suppressive effects. However, the discussion about imatinib's influence on immune cells is still controversial. The aim of this study was to clarify the effect of imatinib on CD8+ and CD4+ T-cell effector functions. MATERIALS AND METHODS: For analyzing T-cell effector functions T-cell receptor-transgenic ovalbumin-specific CD8+ T cells and in vivo primed CD4+ Th1 cells were used. T-cell effector functions were analyzed on the level of antigen responsiveness by intracellular cytokine staining, by measuring cytokine secretion in an interferon-gamma (IFN-gamma) enzyme-linked immunosorbent assay and by detecting cytotoxicity using the fluorescein-activated cell sorting-based fluorometric assessment of T-lymphocyte antigen-specific lysis assay. RESULTS: It was demonstrated that imatinib inhibits antigen-specific IFN-gamma secretion of both CD4+ and CD8+ T-effector cells at therapeutically relevant concentrations, while T cells remain responsive. The decrease of IFN-gamma production was not due to the loss of T-cell viability. Further, it was shown that the effector T cells are modulated rather than suppressed, because the cytolytic functions of CD8+ cytotoxic T cells were not altered. Residual cytolytic activity in the presence of imatinib was not due to FasL interaction. CONCLUSIONS: These experiments provide evidence for a therapeutically relevant modulation of T-cell effector functions by imatinib. This might open a possible applicability of imatinib in various autoimmune and inflammatory diseases, including multiple sclerosis and rheumatoid arthritis.

• Deficiency of the negative immune regulator B7-H1 enhances inflammation and neuropathic pain after chronic constriction injury of mouse sciatic nerve

  Authors: Nurcan Üçeyler, Kerstin Göbel, Sven G. Meuth, Sonja Ortler, Guido Stoll, Claudia Sommer, Heinz Wiendl, Christoph Kleinschnitz

  Experimental Neurology.

  Peripheral nerve injury induces a profound local inflammatory response that involves T cells and macrophages and augments the generation of neuropathic pain. The mechanisms underlying immune cellPeripheral nerve injury induces a profound local inflammatory response that involves T cells and macrophages and augments the generation of neuropathic pain. The mechanisms underlying immune cell activation or inhibition in the peripheral nervous system, however, are unknown. The co-inhibitory molecule B7-H1 (PD-L1, CD274) attenuates immune cell proliferation and cytokine production and protects from inflammation-induced tissue damage. We analyzed the temporal gene expression profile of B7-H1 and different cytokines after chronic constriction injury (CCI) of the sciatic nerve, a lesion paradigm inducing neuropathic pain, by quantitative real-time polymerase chain reaction and immunohistochemistry in B7-H1−/− mice and wild-type (WT) controls. B7-H1 mRNA was markedly induced in WT nerves after CCI, and macrophages could be identified as major B7-H1 source. The proinflammatory mediators tumor necrosis factor alpha (TNFα) and monocyte chemoattractant protein-1 (MCP-1) displayed a strong, but transient expression in degenerating nerves on day 1 after CCI in WT mice, while a biphasic expression peak on day 1 and day 28 was found in B7-H1−/− mice. Overall, TNFα and MCP-1 levels in B7-H1-deficient nerves dramatically exceeded those in WT controls. In contrast, induction of the anti-inflammatory cytokine interleukin(IL)-10 was restricted to WT nerves. The observation that B7-H1 deficiency enhances inflammation upon CCI was further corroborated by immunohistochemistry showing increased numbers of T cells and macrophages in injured nerves from B7-H1−/− mice. Interestingly, mechanical hyperalgesia was more pronounced in the absence of B7-H1. Our study identifies B7-H1 as an important suppressor of the inflammatory response and neuropathic pain occurring after peripheral nerve injury.

• Die Bedeutung koinhibitorischer Signale in der ZNS Immunregulation: die Rolle des B7-Homologs B7-H1 (PD-L1)

  Authors: Sonja Ortler

  Das koinhibitorische Molekül B7-H1 beeinflusst adaptive Immunantworten und ist vermutlich an den Mechanismen zur Aufrechterhaltung peripherer Toleranz und der Limitierung inflammatorischen SchadensDas koinhibitorische Molekül B7-H1 beeinflusst adaptive Immunantworten und ist vermutlich an den Mechanismen zur Aufrechterhaltung peripherer Toleranz und der Limitierung inflammatorischen Schadens beteiligt. Zusätzlich kommt DZ eine entscheidende Bedeutung in der Entwicklung, Aufrechterhaltung und Regulation ZNS-spezifischer Autoimmunität und Inflammationsprozessen zu. Um den B7-H1/PD-1-Signalweg eingehender zu untersuchen, wurden adaptive Immunantworten und die Zielorgan-spezifische Infiltration im Modell der MOG35-55-induzierten EAE analysiert, einem Tiermodell der MS, das durch neurologische Schädigungen und progressive Paralyse bedingt durch die inflammatorische Demyelinisierung im ZNS charakterisiert ist. Im Vergleich zu Wildtyptieren zeigten B7-H1-/- Mäuse einen beschleunigten Krankheitsbeginn und eine signifikante Steigerung des Schweregrads der EAE. Periphere MOG35-55-spezifische IFNg-/IL-17-Immunzellantworten traten in B7-H1-/- Mäusen verfrüht und verstärkt auf, klangen allerdings auch schneller ab. Im ZNS persistierte jedoch eine signifikant höhere Anzahl aktivierter, Neuroantigen-spezifischer T-Zellen während allen Phasen der EAE, wobei diese Zellen ebenfalls größere Mengen proinflammatorischer Zytokine sezernieren konnten. Experimente mit APZ-assoziiertem B7-H1, die einen direkten inhibitorischen Effekt auf die Aktivierung und Proliferation MOG35-55-spezifischer Effektorzellen zeigten, unterstützen die Hypothese, dass parenchymale Expression von B7-H1 ausschlaggebend für das Schicksal von T-Zellen im Zielorgan ist. B7-H1 stellt damit ein Schlüsselmolekül für die Kontrolle parenchymaler Immunreaktionen dar. Nachdem die Relevanz von B7-H1 auf APZ in vitro bewiesen werden konnte, wurde der Einfluss von B7-H1 auf systemisch oder intrazerebral injizierten DZ mit immunogenem oder tolerogenem Phänotyp untersucht. Intravenöse Applikation von tolerogenen B7-H1-/- DZ resultierte in einer besseren Protektion gegen EAE, und dieser Effekt war von einer gesteigerten Produktion Tr1-/Th2-typischer Zytokine sowie einer verstärkten Sekretion von IL-4 und IL-13 durch CD1d-restringierte T-Zellen in der Peripherie begleitet. Die Anzahl Neuroantigen-spezifischer T-Zellen, die proinflammatorische Zytokine sezernierten, war dementsprechend sowohl in der Peripherie als auch im ZNS reduziert. In diesem Zusammenhang konnte für B7-H1 eine wesentliche Beteiligung an der Inhibition der Aktivierung antigen-spezifischer, regulatorischer T-Zellen und CD1d-restringierter T-Zellen gefunden werden. Bei der Injektion intrazerebraler DZ bewirkten tolerogene DZ im Vergleich zu immunogenen DZ eine Reduktion der ZNS-Infiltration mit CD4+ T-Zellen in der frühen Phase der Erkrankung. Außerdem konnte eine Veränderung des intrazerebralen Zytokinmilieus von IFNg/IL-17 exprimierenden enzephalitogenen T-Zellen zu IL-10+ regulatorischen T-Zellen gezeigt werden. B7-H1-Defizienz auf APZ verstärkte diesen Effekt und führte dadurch in den Mäusen zur partiellen Protektion gegen klinische Symptome der EAE. Zusätzlich wurde die Beteiligung von B7-H1 an der Rekrutierung und ZNS-lokalisierten Induktion der Proliferation CD8+ regulatorischer T-Zellen durch DZ beschrieben. Unabhängig vom Phänotyp der DZ wurde eine bereits in der frühen Phase vorhandene und dauerhaft expandierende Population von CD8+ T-Zellen im ZNS DZ[B7-H1-/-]-injizierter Mäuse gefunden. Diese Zellen konnten in vitro die Proliferation MOG35-55-spezifischer CD4+ T-Zellen supprimieren und wirkten so mutmaßlich an der Abmilderung der EAE mit. Zusammengefasst zeigen die Ergebnisse dieser Arbeit die entscheidende Bedeutung von B7 H1 auf DZ als immuninhibitorisches Molekül, das sowohl enzephalitogene als auch regulatorische T-Zell-Antworten moduliert und damit zur Limitation von Immunantworten beiträgt. The coinhibitory B7-H1 molecule influences adaptive immune responses and has been proposed to contribute to the mechanisms maintaining peripheral tolerance and limiting inflammatory damage in parenchymal organs. Additionally, DC emerge as crucial immune cell population during development, maintenance and regulation of CNS-specific autoimmunity and inflammation. To further explore the B7-H1/PD1 pathway in CNS autoimmune inflammation, adaptive immune responses and target organ infiltration were analysed in MOG35-55-induced EAE, an animal model of MS characterized by neurological impairment and progressive paralysis resulting from inflammatory demyelination in the CNS. In comparison to wildtype mice B7 H1-/- mice exhibited an accelerated disease onset and significantly exacerbated EAE severity. Peripheral MOG35-55-specific IFNg/IL-17 T cell responses occurred earlier and enhanced in B7-H1-/- mice, but ceased more rapidly. In the CNS, however, significantly higher numbers of activated neuroantigen-specific T cells persisted during all stages of EAE and were able to secrete higher amounts of proinflammatory cytokines. Experiments showing a direct inhibitory role of APC-derived B7-H1 on the activation and proliferation of MOG35-55-specific effector cells support the assumption that parenchymal B7 H1 is pivotal for delineating T cell fate in the target organ. Therefore, B7-H1 represents a key molecule in the control of parenchymal immune reactions. Having shown the critical relevance of B7-H1 on APC in vitro, the influence of B7-H1 expression on systemically or intracerebrally injected DC displaying an immunogenic or tolerogenic phenotype was investigated. Intravenous application of tolerogenic B7-H1-/- DC resulted in a more efficient protection from EAE, accompanied by an increased peripheral production of Tr1/Th2 cytokines and a pronounced secretion of IL-4 and IL-13 by CD1d-restricted T cells. In accordance, numbers of neuroantigen-specific T cells secreting proinflammatory cytokines were reduced both in the periphery and in the CNS. Here, a substantial contribution of B7-H1 to inhibition of activation of antigen-specific, regulatory T cells and CD1d-restricted T cells could be found. Using intracerebral DC injections, a reduction of early CNS CD4+ T cell infiltration was shown for tolerogenic DC compared to immunogenic DC. Furthermore, alteration of the intracerebral cytokine milieu containing IFNg+/IL-17+ encephalitogenic T cells to IL 10+ regulatory T cells was demonstrated. B7-H1 deficiency on DC enhanced this effect, thereby mediating partial protection of mice from clinical signs of EAE. Additionally, involvement of B7-H1 expression on the ability of DC to recruit and induce proliferation of CD8 regulatory T cells locally in the CNS was described. Regardless of DC phenotype, an early and consistently expanding population of CD8+ T cells was observed in the CNS of DC[B7-H1-/-]-injected mice, which was able to suppress proliferation of MOG35-55-specific CD4+ T cells in vitro and thus probably contributes to EAE amelioration in vivo. Taken together, the findings of this study demonstrate the critical importance of DC-derived B7-H1 as an immune-inhibitory molecule capable of modulating both encephalitogenic and regulatory T cell responses thus contributing to the confinement of immune responses.