IL-10 down-regulates T cell activation by antigen-presenting liver sinusoidal endothelial cells through decreased antigen uptake via the mannose receptor and lowered surface expression of accessory molecules.

SUMMARYOur study demonstrates that antigen-presenting liver sinusoidal endothelial cells (LSEC) induce production of interferon-gamma (IFN-γ) from cloned Th1 CD4+ T cells. We show that LSEC used the mannose receptor for antigen uptake, which further strengthened the role of LSEC as antigen-presenting cell (APC) population in the liver. The ability of LSEC to activate cloned CD4+ T cells antigen-specifically was down-regulated by exogenous prostaglandin E2 (PGE2) and by IL-10. We identify two separate mechanisms by which IL-10 down-regulated T cell activation through LSEC. IL-10 decreased the constitutive surface expression of MHC class II as well as of the accessory molecules CD80 and CD86 …

Tolerance towards resident intestinal flora in mice is abrogated in experimental colitis and restored by treatment with interleukin-10 or antibodies to interleukin-12

There is now increasing evidence that hyperresponsiveness towards intestinal flora is a crucial event in the pathogenesis of inflammatory bowel disease (IBD). In support of this hypothesis, we recently described in humans that tolerance exists towards indigenous intestinal flora but is broken in active IBD lesions. In the present study, we have attempted to transfer this model into mice from different genetic backgrounds (BALB/c, SJL/J, C3H/HeJ). We found that mononuclear cells from spleen, small bowel and large bowel of mice do not proliferate, i.e. are tolerant when exposed to bacterial sonicates derived from autologous intestine (BsA) but do proliferate, i.e. are immune when exposed to b…

Antigen-presenting function and B7 expression of murine sinusoidal endothelial cells and Kupffer cells.

Abstract BACKGROUND & AIMS: Inflammatory liver disease as well as rejection of liver allografts are thought to be mediated by resident antigen- presenting cells in the liver. At the same time, in vivo antigen presentation in the liver appears to be a more tolerogenic than systemic antigen challenge. The aim of this study was to show and characterize the antigen-presenting capability of sinusoidal endothelial cells and Kupffer cells. METHODS: Purified murine sinusoidal endothelial cells and Kupffer cells were studied for their ability to serve as accessory cells and antigen-presenting cells by proliferation assays. They were also studied for their expression of interleukin 1 and the B7 costi…

Intrahepatic myeloid-cell aggregates enable local proliferation of CD8+T cells and successful immunotherapy against chronic viral liver infection

Chronic infection is difficult to overcome because of exhaustion or depletion of cytotoxic effector CD8(+) T cells (cytotoxic T lymphoytes (CTLs)). Here we report that signaling via Toll-like receptors (TLRs) induced intrahepatic aggregates of myeloid cells that enabled the population expansion of CTLs (iMATEs: 'intrahepatic myeloid-cell aggregates for T cell population expansion') without causing immunopathology. In the liver, CTL proliferation was restricted to iMATEs that were composed of inflammatory monocyte-derived CD11b(+) cells. Signaling via tumor-necrosis factor (TNF) caused iMATE formation that facilitated costimulation dependent on the receptor OX40 for expansion of the CTL popu…

T cell specificity and cross reactivity towards enterobacteria,Bacteroides,Bifidobacterium, and antigens from resident intestinal flora in humans

BACKGROUNDT cell responses to normal intestinal bacteria or their products may be important in the immunopathogenesis of chronic enterocolitis.AIMSTo investigate the T cell specificity and cross reactivity towards intestinal bacteria.PATIENTS/METHODST cell clones were isolated with phytohaemagglutinin from peripheral blood and biopsy specimens of inflamed and non-inflamed colon from five patients with inflammatory bowel disease (IBD) and two controls. T cell clones were restimulated with anaerobicBacteroides andBifidobacteria species, enterobacteria, and direct isolates of aerobic intestinal flora. T cell phenotype was analysed by single-cell immunocyte assay.RESULTSAnalysis of 96 T cell cl…

Induction of cytokine production in naive CD4+ T cells by antigen-presenting murine liver sinusoidal endothelial cells but failure to induce differentiation toward Th1 cells☆, ☆☆

Abstract Background & Aims: Murine liver sinusoidal endothelial cells (LSECs) constitutively express accessory molecules and can present antigen to memory Th1 CD4+ T cells. Using a T-cell receptor transgenic mouse line, we addressed the question whether LSECs can prime naive CD4+ T cells. Methods: Purified LSECs were investigated for their ability to induce activation and differentiation of naive CD4+ T cells in comparison with bone marrow–derived antigen-presenting cells and macrovascular endothelial cells. Activation of T cells was determined by cytokine production. LSECs were further studied for expression of interleukin (IL)-12 by reverse-transcription polymerase chain reaction, and the…

Elevated serum E-selectin in patients with liver metastases of colorectal cancer

E-selectin, an endothelial cell adhesion molecule, mediates the initial step of leucocyte adhesion to activated vascular endothelium. The soluble isoform of E-selectin promotes angiogenesis in rat cornea. In the present study, we investigated whether leucocyte adhesion and angiogenesis are also involved in tumour progression and metastasis of colorectal cancer. Therefore, we determined the level of circulating soluble E-selectin in serum samples of 38 patients with colorectal cancer; 20 patients with non-metastatic and 18 patients with metastatic disease. Median levels of soluble E-selectin were found to be significantly higher in metastatic tumour disease (88.7 ng/ml, range 25-203 ng/ml) t…

Sustained elimination of hepatitis B virus from serum induced in a patient with chronic hepatitis B and advanced human immunodeficiency virus infection

A 48-year-old male patient was admitted with acquired immunodeficiency syndrome (stage III, Centers for Disease Control 1993) and viremic hepatitis B. Blood CD4 count was 15/microliters. Discontinuation of prednisolone, previously prescribed by the patient's family practitioner because of elevated liver enzymes, resulted in severe hepatitis (alanine aminotransferase > 300U/l). Administration of interferon-alpha (9 x 10(6) U s.c. 3 x weekly) was initiated. Serum markers of viral replication disappeared, and aminotransferase levels returned to normal within a few weeks. The patient's serum was found negative for HBsAg after 3 months. Immunohistochemical analysis of liver biopsies before and d…

Liver-primed memory T cells generated under noninflammatory conditions provide anti-infectious immunity.

SummaryDevelopment of CD8+ T cell (CTL) immunity or tolerance is linked to the conditions during T cell priming. Dendritic cells (DCs) matured during inflammation generate effector/memory T cells, whereas immature DCs cause T cell deletion/anergy. We identify a third outcome of T cell priming in absence of inflammation enabled by cross-presenting liver sinusoidal endothelial cells. Such priming generated memory T cells that were spared from deletion by immature DCs. Similar to central memory T cells, liver-primed T cells differentiated into effector CTLs upon antigen re-encounter on matured DCs even after prolonged absence of antigen. Their reactivation required combinatorial signaling thro…

Akutes Lungenversagen bei Malaria tropica in der Schwangerschaft: Erfolgreiche Behandlung durch extrakorporale CO2-Elimination

Eine 32jahrige Schwangere (26. Schwangerschaftswoche) erkrankte am 6. Tag nach der Ruckkehr von einem Indonesienaufenthalt mit Fieber bis 42°C, hamolytischer Anamie (Hamoglobin 7,6 g/dl) und Thrombozytopenie (7000/µl). Es wurde eine Malaria diagnostiziert; eine Prophylaxe hatte sie nicht durchgefuhrt. Unter antiparasitarer Chemotherapie mit Chloroquin, Chinin und Pyrimethamin kam es zur Elimination der Parasiten (Makrogametozyten von Plasmodium falciparum) aus dem peripheren Blut. Im weiteren Verlauf entwickelte sich jedoch ein progredientes Lungenversagen und eine therapierefraktare Pneumonie, die zu einem »adult respiratory distress syndrome« (ARDS; Morel-Stadium 4) fuhrten. Bei drohendem…

Role of sinusoidal endothelial cells of the liver in concanavalin A-induced hepatic injury in mice

CD4+ T lymphocytes have been identified as being responsible for organ damage in the murine model of experimental liver injury induced by intravenous injection of concanavalin A (Con A). Liver sinusoidal endothelial cells (SEC) and Kupffer's cells (KC) are among the first cells that come into contact with lymphocytes in the liver sinusoid. We aimed to investigate the respective role of these cell populations in the initial steps of T-cell-mediated liver injury in Con A-induced hepatitis. By electron microscopy, we could show that intravenously applied Con A bound predominantly to SEC but not to KC. KC depletion by gadolinium chloride treatment of mice did not result in protection from liver…

Sodium chloride is an ionic checkpoint for human Th2 cell responses and shapes the atopic skin microenvironment

One sentence summarySodium is an ionic checkpoint for the induction and amplification of human Th2 cell responses and shapes the atopic skin microenvironment, where it could serve as a novel therapeutic target for Th2 mediated diseases.AbstractThere has been a strong increase in the incidence of allergic diseases over the last 50 years. Environmental factors most likely account for this phenomenon. However, the nature of these factors and the mode of action by which they induce the type 2 immune deviation, which is characteristic of atopic diseases, remains unclear. It has previously been reported that dietary sodium chloride promotes the polarization of Th17 cells with implications for aut…

Viral and host factors in the prediction of response to interferon-alpha therapy in chronic hepatitis C after long-term follow-up.

Acute infection with hepatitis C virus (HCV) develops into a chronic hepatitis in about 50-70% of patients. Treatment of these patients with interferon-alpha (IFN-alpha) results in a sustained long-term response in only 15-20% but causes numerous unwanted side-effects in a higher percentage of patients. The aim of our study was to define host or viral parameters that would allow identification of responders and non-responders to IFN-alpha prior to the onset of treatment. We studied a group of 87 patients suffering from chronic hepatitis C who were treated with IFN-alpha. After long-term follow-up, 18 patients (21%) showed a sustained response to IFN-alpha therapy (normalization of serum tra…

HIV und Schwangerschaft: Risiken der Übertragung und therapeutische Möglichkeiten

Die Rate der vertikalen Ubertragung von HIV im Rahmen einer Schwangerschaft liegt in Europa bei etwa 14% aller HIV-infizierten Schwangeren. Risikofaktoren sind: 1. Virusmenge gemessen an p-24-Antigenamie und Hohe der HIV-RNA-Serumkonzentrationen, 2. Abfall der CD4-Lymphozyten unter 600/µl, 3. Chorioamnionitis und 4. Zeitintervall zwischen Blasensprung und Entbindung. Stillen und vaginale Entbindung erhohen die HIV-Infektionsrate des Kindes. Durch antiretrovirale Therapie mit Azidothymidin (Retrovir®) in einer Dosis von 500 mg/Tag wird die vertikale Ubertragung um 67% reduziert. Teratogene oder mutagene Nebenwirkungen sind bisher nicht nachgewiesen worden. Die Progression der HlV-Infektion d…

Semiquantitative assessment of pre-core stop-codon mutant and wildtype hepatitis B virus during the course of chronic hepatitis B using a new PCR-based assay

In most patients with chronic hepatitis B positive for antibodies (anti-HBe) to HBe antigen (HBeAg), a pre-core mutant hepatitis B virus (HBV) with a point-mutation at nt. 1896 can be isolated. Clinical significance of the mutant virus in chronic hepatitis B is not proven yet, and screening of large numbers of sera during different clinical courses of numerous patients is necessary. We therefore aimed to develop a fast and reliable assay, that allows to discriminate wildtype from nt. 1896 G-->A mutant HBV and to determine the ratio of mutant and wildtype HBV in patients' sera. A mutation specific polymerase chain reaction (ms PCR) with new primers served to distinguish nt. 1896 G-->A mutant…

Involvement of B cells in Non-Alcoholic Steatohepatitis (NASH)