The nuclear receptor PPARγ selectively inhibits Th17 differentiation in a T cell–intrinsic fashion and suppresses CNS autoimmunity
T helper cells secreting interleukin (IL)-17 (Th17 cells) play a crucial role in autoimmune diseases like multiple sclerosis (MS). Th17 differentiation, which is induced by a combination of transforming growth factor (TGF)-beta/IL-6 or IL-21, requires expression of the transcription factor retinoic acid receptor-related orphan receptor gamma t (ROR gamma t). We identify the nuclear receptor peroxisome proliferator-activated receptor gamma (PPAR gamma) as a key negative regulator of human and mouse Th17 differentiation. PPAR gamma activation in CD4(+) T cells selectively suppressed Th17 differentiation, but not differentiation into Th1, Th2, or regulatory T cells. Control of Th17 differentia…
Virally Infected Mouse Liver Endothelial Cells Trigger CD8+ T-Cell Immunity
Background & Aims Dendritic cell activation through ligation of pattern recognition receptors leading to full functional maturation causes induction of CD8 + T-cell immunity through increased delivery of costimulatory signals instead of tolerance. Here we investigate whether organ-resident antigen-presenting cells, such as liver sinusoidal endothelial cells (LSECs), also switch from tolerogenic to immunogenic CD8 + T-cell activation upon such stimulation. Methods Murine LSECs were isolated by immunomagnetic separation and analyzed for functional maturation upon triggering pattern recognition receptors or viral infection employing gene expression analysis and T cell coculture assays. In vivo…
Normal interleukin-12 production in individuals with antibodies toHelicobacter pylori
It is increasingly recognized that the inability of the immune system to clear H. pylori infection is caused by an inadequate immune response and is associated with chronic gastric inflammation. To further investigate the cellular immune response to H. pylori, we studied PBMC from 31 H. pylori antibody-negative and 16 H. pylori antibody-positive individuals for H. pylori-induced DNA synthesis, secretion of the Th1-type cytokine IFN-gamma and secretion of IL-12, a cytokine produced by bacteria-stimulated monocyte/macrophages and a potent inducer of antibacterial immune responses and Th1-type T cells. All experiments were performed using Y. enterocolitica 03 as control. Our results demonstrat…
Dynamic regulation of CD8 T cell tolerance induction by liver sinusoidal endothelial cells.
Abstract Cross-presentation of soluble Ag on MHC class I molecules to naive CD8 T cells by liver sinusoidal endothelial cells (LSECs) leads to induction of T cell tolerance that requires interaction between coinhibitory B7-H1 on LSECs and programmed cell death-1 on CD8 T cells. In this study, we investigate whether cross-presentation of high as well as low Ag concentrations allowed for LSEC-induced tolerance. Ag concentration directly correlated with the cross-presentation capacity of murine LSECs and thus strength of TCR stimulation. Although LSEC cross-presentation at low-Ag concentrations resulted in tolerance, they induced differentiation into effector T cells (CTL) at high-Ag concentra…
Effects of Th1 and Th2 cytokines on cytokine production and ICAM-1 expression on synovial fibroblasts
OBJECTIVES--To investigate the influence of the Th1 and Th2 lymphokines interleukins (IL)-4 and IL-13, interferon gamma (IFN gamma), and several monokines on the adhesion of mononuclear cells to synovial fibroblasts and intercellular adhesion molecule-1 (ICAM-1) expression and cytokine production of synovial fibroblasts in patients with osteoarthritis. METHODS--Synovial fibroblasts were isolated from patients with osteoarthritis and stimulated with IL-1 beta, IL-4, IL-6, IL-10, IL-12, IL-13, tumour necrosis factor alpha (TNF alpha), and IFN gamma. Subsequently, we determined the production of IL-1 alpha, IL-1 beta, IL-6, IL-10, IL-12, IFN alpha and TNF alpha, and the expression of ICAM-1 ly…
Sodium chloride is an ionic checkpoint for human TH2 cells and shapes the atopic skin microenvironment.
The incidence of allergic diseases has increased over the past 50 years, likely due to environmental factors. However, the nature of these factors and the mode of action by which they induce the type 2 immune deviation characteristic of atopic diseases remain unclear. It has previously been reported that dietary sodium chloride promotes the polarization of T helper 17 (T(H)17) cells with implications for autoimmune diseases such as multiple sclerosis. Here, we demonstrate that sodium chloride also potently promotes T(H)2 cell responses on multiple regulatory levels. Sodium chloride enhanced interleukin-4 (IL-4) and IL-13 production while suppressing interferon-gamma (IFN-gamma) production i…
Regulation of endotoxin-induced IL-6 production in liver sinusoidal endothelial cells and Kupffer cells by IL-10
SUMMARY Sinusoidal endothelial cells and Kupffer cells are the first cell populations in the liver that come into contact with gut-derived endotoxin in portal blood. Although endotoxin concentrations as high as 1 ng/ml are physiologically present in portal blood, no local inflammation is seen. We show that the proinflammatory cytokine IL-6, which is central to the development of inflammatory reactions in the liver, is produced by sinusoidal endothelial cells and Kupffer cells in response to low concentrations of endotoxin (100 pg/ml to 1 ng/ml). The anti-inflammatory cytokine IL-10 down-regulated endotoxin-induced IL-6 release in endothelial and Kupffer cells. Importantly, Kupffer cells sec…
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…
MHC class II genes influence the susceptibility to chronic active hepatitis C
Chronic hepatitis C develops in more than 70% of hepatitis C virus infected subjects. Viral factors influence the disease course, but little is known about the importance of host factors.Frequencies of major histocompatibility complex (MHC) class I and class II antigens were analyzed in two groups of patients with chronic hepatitis C virus infection and in control subjects. MHC class I typing was done by standard microlymphocytotoxicity assays. DRB1 and DQA1 genotyping was done by PCR based typing methods.DRB1*0301 was found in 26 of 75 patients with chronic hepatitis C virus infection (34.7%) and in 12 of 101 control subjects (11.9%) (relative risk 3.9; p0.001). Homozygosity for this allel…
Interleukin-10 expression is autoregulated at the transcriptional level in human and murine kupffer cells
Interleukin 10 (IL-10) is known to downregulate immune responses. The regulation of IL-10 gene expression therefore determines the outcome of local immune reactions. We investigated time course and downregulation of IL-10 production in primary Kupffer's cells (KC), which are known to secrete IL-10 in response to endotoxin challenge. Human and murine KC were isolated by centrifugal elutriation and investigated for IL-10 gene expression by a two-step amplification procedure (reverse transcriptase-polymerase chain reaction [PCR] followed by T7-polymerase chain reaction). We show that IL-10 messenger ribonucleic acid (mRNA) showed a >450 fold increase in KC 2 hours after endotoxin challenge. IL…
Ligase Chain Reaction (LCR®) assay for semi-quantitative detection of HBV DNA in mononuclear leukocytes of patients with chronic hepatitis B
Summary. A ligase chain reaction (LCR®)-based approach to detect hepatitis B virus (HBV) DNA in peripheral blood mononuclear cells (PBMC) is described. Using this new amplification technique, we determined semi-quantitatively the amount of a short HBV S-gene fragment in PBMC lysates of 25 patients with different forms of chronic hepatitis (group A (n= 8), hepatitis B s antigen (HBsAg)+/hepatitis B e antigen (HBeAg)+; group B (n= 9), HBsAg+/HBeAg-; group C (n= 8), HBsAg-/HBeAg-). The LCR results were compared with the findings obtained with polymerase chain reaction (PCR) amplification of three distinct HBV gene regions (preS1/2, S and C) and related to the serological profiles of the patien…
T cells expressing a chimeric antigen receptor that binds hepatitis B virus envelope proteins control virus replication in mice.
Background & Aims Antiviral agents suppress hepatitis B virus (HBV) replication but do not clear the infection. A strong effector T-cell response is required to eradicate HBV, but this does not occur in patients with chronic infection. T cells might be directed toward virus-infected cells by expressing HBV-specific receptors and thereby clear HBV and help to prevent development of liver cancer. In mice, we studied whether redirected T cells can engraft after adoptive transfer, without prior T-cell depletion, and whether the large amounts of circulating viral antigens inactivate the transferred T cells or lead to uncontrolled immune-mediated damage. Methods CD8 + T cells were isolated from m…
Rare pre-core stop-codon mutant nt. 1897 predominates over wide-spread mutant nt. 1896 in an unusual course of chronic hepatitis B
We present a patient with an unusual course of hepatitis B e antigen (HBeAg)-negative chronic hepatitis B who had repeated reactivations of his disease progressing to cirrhosis with terminal liver failure. Each flare up presented like an acute hepatitis with very high titres of hepatitis B virus (HBV) and high inflammatory activity followed by rapid clearance of viraemia. The pre-core genome of HBV isolated from sera during 5 years of follow up was analysed. Direct sequencing of polymerase chain reaction (PCR) products derived from consecutive sera showed a rare pre-core stop-codon mutation at nucleotide (nt.) 1897 G --> A with an accompanying mutation nt. 1857 C --> T as well as a stop-cod…
Complete congenital heart block in autoimmune hepatitis (SLA-positive).
Complete congenital heart block is a serious complication of neonatal lupus erythematosus which most often occurs in children of mothers suffering from connective tissue disease. We report the occurrence of complete congenital heart block associated with autoimmune hepatitis (SLA-positive). A 32-year-old woman was treated for more than 10 years for autoimmune hepatitis (SLA-/ANA-positive) and remained in clinical remission under immunosuppressive therapy. She showed an MHC-haplotype typical for autoimmune hepatitis (A1, B8, DR3). After a normal first pregnancy, an emergency caesarean section was performed in the 32nd week of her second pregnancy because of fetal bradycardia. The child died …