Downregulation Of Th1 Research Articles

Blockade of interleukin-6 signaling inhibits the classic pathway and promotes an alternative pathway of macrophage activation after spinal cord injury in mice

BackgroundRecent in vivo and in vitro studies in non-neuronal and neuronal tissues have shown that different pathways of macrophage activation result in cells with different properties. Interleukin (IL)-6 triggers the classically activated inflammatory macrophages (M1 phenotype), whereas the alternatively activated macrophages (M2 phenotype) are anti-inflammatory. The objective of this study was to clarify the effects of a temporal blockade of IL-6/IL-6 receptor (IL-6R) engagement, using an anti-mouse IL-6R monoclonal antibody (MR16-1), on macrophage activation and the inflammatory response in the acute phase after spinal cord injury (SCI) in mice.MethodsMR16-1 antibodies versus isotype control antibodies or saline alone were administered immediately after thoracic SCI in mice. SC tissue repair was compared between the two groups by Luxol fast blue (LFB) staining for myelination and immunoreactivity for the neuronal markers growth-associated protein (GAP)-43 and neurofilament heavy 200 kDa (NF-H) and for locomotor function. The expression of T helper (Th)1 cytokines (interferon (IFN)-γ and tumor necrosis factor-α) and Th2 cytokines (IL-4, IL-13) was determined by immunoblot analysis. The presence of M1 (inducible nitric oxide synthase (iNOS)-positive, CD16/32-positive) and M2 (arginase 1-positive, CD206-positive) macrophages was determined by immunohistology. Using flow cytometry, we also quantified IFN-γ and IL-4 levels in neutrophils, microglia, and macrophages, and Mac-2 (macrophage antigen-2) and Mac-3 in M2 macrophages and microglia.ResultsLFB-positive spared myelin was increased in the MR16-1-treated group compared with the controls, and this increase correlated with enhanced positivity for GAP-43 or NF-H, and improved locomotor Basso Mouse Scale scores. Immunoblot analysis of the MR16-1-treated samples identified downregulation of Th1 and upregulation of Th2 cytokines. Whereas iNOS-positive, CD16/32-positive M1 macrophages were the predominant phenotype in the injured SC of non-treated control mice, MR16-1 treatment promoted arginase 1-positive, CD206-positive M2 macrophages, with preferential localization of these cells at the injury site. MR16-1 treatment suppressed the number of IFN-γ-positive neutrophils, and increased the number of microglia present and their positivity for IL-4. Among the arginase 1-positive M2 macrophages, MR16-1 treatment increased positivity for Mac-2 and Mac-3, suggestive of increased phagocytic behavior.ConclusionThe results suggest that temporal blockade of IL-6 signaling after SCI abrogates damaging inflammatory activity and promotes functional recovery by promoting the formation of alternatively activated M2 macrophages.

Regulatory T cells expanded by rapamycin in vitro suppress colitis in an experimental mouse model

To provide rapid immunosuppression without side effects, we analyzed whether rapamycin alone, and regulatory T cells (Tregs) expanded ex vivo by rapamycin, suppressed colitis in a mouse model. Severe combined immunodeficiency (SCID) mice reconstituted with naive CD4(+) T cells were treated with or without intraperitoneal rapamycin. Body weight was evaluated. CD4(+) T cells were cultured in the presence of rapamycin for three 7-day rounds of stimulation. The ratio of Tregs to CD4(+) T cells was analyzed by flow cytometry. Naive CD4(+) T cells were transferred into SCID mice with CD4(+) T cells expanded in the presence or absence of rapamycin. Clinical symptoms of colitis, histological changes, and cytokine expression were investigated. Systemic rapamycin partially prevented the development of colonic inflammation in a transfer model of colitis, but decreased body weight in control mice. With rapamycin, stimulated CD4(+) T cells expanded eightfold in 3 weeks in vitro, and the proportion of Tregs increased to about 40%. Without rapamycin, CD4(+) T cells expanded 20-fold in 3 weeks, but the proportion of Tregs remained at about 15%. CD4(+) T cells expanded with rapamycin prevented the development of colitis in a naïve CD4(+) T-cell transfer model, in association with the downregulation of Th1 and Th17 responses. We demonstrated, for the first time, that CD4(+) T cells expanded with rapamycin in vitro suppressed colitis. Therefore, rapamycin-expanded Treg transfer therapy is expected to be efficacious for inflammatory bowel disease.

Coinfection with Enterohepatic Helicobacter Species Can Ameliorate or Promote Helicobacter pylori-Induced Gastric Pathology in C57BL/6 Mice

To investigate how different enterohepatic Helicobacter species (EHS) influence Helicobacter pylori gastric pathology, C57BL/6 mice were infected with Helicobacter hepaticus or Helicobacter muridarum, followed by H. pylori infection 2 weeks later. Compared to H. pylori-infected mice, mice infected with H. muridarum and H. pylori (HmHp mice) developed significantly lower histopathologic activity index (HAI) scores (P < 0.0001) at 6 and 11 months postinoculation (MPI). However, mice infected with H. hepaticus and H. pylori (HhHp mice) developed more severe gastric pathology at 6 MPI (P = 0.01), with a HAI at 11 MPI (P = 0.8) similar to that of H. pylori-infected mice. H. muridarum-mediated attenuation of gastritis in coinfected mice was associated with significant downregulation of proinflammatory Th1 (interlukin-1beta [Il-1β], gamma interferon [Ifn-γ], and tumor necrosis factor-alpha [Tnf-α]) cytokines at both time points and Th17 (Il-17A) cytokine mRNA levels at 6 MPI in murine stomachs compared to those of H. pylori-infected mice (P < 0.01). Coinfection with H. hepaticus also suppressed H. pylori-induced elevation of gastric Th1 cytokines Ifn-γ and Tnf-α (P < 0.0001) but increased Th17 cytokine mRNA levels (P = 0.028) at 6 MPI. Furthermore, mRNA levels of Il-17A were positively correlated with the severity of helicobacter-induced gastric pathology (HhHp>H. pylori>HmHp) (at 6 MPI, r² = 0.92, P < 0.0001; at 11 MPI, r² = 0.82, P < 0.002). Despite disparate effects on gastritis, colonization levels of gastric H. pylori were increased in HhHp mice (at 6 MPI) and HmHp mice (at both time points) compared to those in mono-H. pylori-infected mice. These data suggest that despite consistent downregulation of Th1 responses, EHS coinfection either attenuated or promoted the severity of H. pylori-induced gastric pathology in C57BL/6 mice. This modulation was related to the variable effects of EHS on gastric interleukin 17 (IL-17) responses to H. pylori infection.

Hookworm products ameliorate dextran sodium sulfate-induced colitis in BALB/c mice

Several lines of evidence have shown that helminthiasis can significantly reduce disease severity in animal models of intestinal inflammation, airway inflammation/hyperreactivity, diabetes, and multiple sclerosis. Identification and characterization of helminth-derived immunomodulatory molecules that contribute to anticolitis effects could lead to new therapeutic approaches in inflammatory bowel diseases (IBDs) without the need for helminth infection. We evaluated the therapeutic potential of adult human hookworm, Ancylostoma ceylanicum, crude (Aw) and excreted/secreted (ES) products on dextran sulfate sodium (DSS)-induced colitis in BALB/c mice. Colitis was induced by 5% DSS oral administration for 7 days. Clinical disease severity was monitored daily during concomitant intraperitoneal treatment with helminth-derived products. Additionally, several pathways of immunological modulation induced by A. ceylanicum products (MPO, EPO, Th1, Th2, and Th17 cytokine responses) in the inflamed intestinal microenvironment were assessed. Finally, the histopathological profile of the colon was characterized. Hookworm products are able to modulate the potent proinflammatory response induced by DSS, mainly through the downregulation of Th1 and Th17 cytokines. These proteins also reduce clinical and colonic microscopic inflammation scores as well as EPO and MPO activity. Ancylostoma ceylanicum Aw and ES mediators have an important therapeutic potential in experimental colitis in mice, which may provide a more socially acceptable form of therapy for patients with IBDs as opposed to using living worms. Our results support the urgency of further isolation and recombinant expression of active hookworm products responsible for the beneficial effects on colitis.

Treatment With Interleukin-12/23p40 Antibody Attenuates Acute Cardiac Allograft Rejection

Interleukin (IL)-12 and -23 share the p40 subunit and are crucial for the development of T helper (Th) 1- and Th17-cell responses in acute graft rejection. However, little is known about the impact of treatment with antagonistic anti-p40 antibody in inhibiting rejection of cardiac allografts. C57BL/6 mice were transplanted with syngeneic or allogeneic (BALB/c) hearts and treated with 100 or 200 μg or 400 μg anti-P40 monoclonal antibody on postoperative days 1 and 3, respectively. The survival of grafts was monitored daily by abdominal palpation until the complete cessation of cardiac contractility (endpoint). The severity of acute rejection was evaluated by histology and immunohistochemistry. The expression of transcription factors within the grafts were measured by quantitative real-time polymerase chain reaction. Systemically, the lymphocytes were characterized by flow cytometry, and the serum levels of cytokines were determined by ELISA. In comparison with mice treated with isotype IgG or saline, treatment with anti-p40 significantly alleviated acute phase allograft rejection and resulted in prolonged survival of cardiac allografts (P<0.05). These changes were associated with reduced infiltration of inflammatory cells and down-regulation of Th1- and Th17-specific transcription factors and cytokines. Furthermore, treatment with anti-p40 significantly reduced the percentages of splenic Th1 and Th17 cells, but not Th2 and regulatory T cells (P<0.05), with concomitant reduction of serum interferon-γ and IL-17 levels (P<0.05). Our data indicated that treatment with anti-p40 inhibited Th1- and Th17-cell responses and prolonged the survival of cardiac allografts in mice.

S1713 IL-12/IL-23 P40 Peptide-Based Vaccine Ameliorates TNBS-Induced Murine Chronic Colitis By Down-Regulation of TH1 and TH17 Cytokines

BACKGROUND: The aetiology of crohn's disease (CD) is poorly understood at present, but an immune pathology involving the CD4+T-cell phenotypes is suspected to be a major factor for the development and the perpetuation of CD. In line with this thinking, recently, we found that in patients with ulcerative colitis, the peripheral level of the regulatory CD4+CD25High+ T-cell phenotype was compromised, while the CD4+ T-cells lacking CD28 (CD4+CD28-) had expanded (Dig Dis Sci 2007;52:2725-31). We have now extended our work to patients with CD. METHODS: The study subjects included 31 patients with active CD (aCD) who were to be treated with infliximab (IFX). At baseline, the mean values of CD activity index (CDAI) and the duration of CD were 200.9±84.8 and 5.7±7.0 years, respectively. Sixteen patients with CD in remission (rCD, CDAI≤150) and 19 healthy control (HC) subjects were also included in this study. Fifteen patients received IFX as initial (top down) therapy, 7 received IFX as an episodic (step up) therapy, and the other 9 received IFX after operation. Peripheral blood samples were obtained before and 12 hours after each IFX infusion. Lymphocytes were stained with anti CD4, anti CD25 and anti CD28 antibodies for analyses by fluorescence-activated cell sorter (FACS) in flow cytometry. RESULTS: The aCD group had significantly lower level of CD4+CD25High+ T-cell expression as compared with the rCD group (P<0.05) or the HC group (P<0.05). A significant up-regulation of CD4+CD25High+ T-cell phenotype was associated with the post first IFX infusion as compared with the pre first IFX infusion (P<0.01). Conversely, patients with aCD had higher % CD4+CD28T-cells as compared with the rCD group (P<0.05) or the HC group (P<0.05). A significant down-modulation of the CD4+CD28T-cell phenotype was associated with post first IFX infusion vs pre first IFX infusion (P<0.01) CONDLUSIONS: IFX therapy was associated with a marked improvement of patients' quality of life, but our clinical observations indicated that the efficacy of IFX diminishes after frequently administration. However, in this study, the clinical efficacy of IFX was associated with a significant up modulation of the regulatory CD4+CD25High+ T-cell phenotype and unexpectedly, some normalization of peripheral CD4+CD28T-cell phenotype. We believe that a likely impact of IFX on key cells of the immune system is potentially very significant and warrants to be substantiated in future studies.

Schistosoma mansoni infection reduces severity of collagen-induced arthritis via down-regulation of pro-inflammatory mediators

Various experimental and epidemiological studies have demonstrated that helminth infections affect outcomes of allergic or autoimmune disorders. Here, we examined the effects of Schistosoma mansoni infection on mouse collagen-induced arthritis, one of the most widely used animal models for rheumatoid arthritis. Male DBA/1 mice were infected with S. mansoni 2 weeks prior to being immunized with type II collagen (IIC). Cytokine mRNA expression in mouse paws, cytokine production by ConA-stimulated spleen cells, and anti-IIC antibodies were evaluated in addition to the severity of arthritis. S. mansoni infection significantly reduced the severity of arthritis. Anti-IIC IgG and IgG2a levels were lower in infected than uninfected mice. With regard to cytokine producing potentials in the infected mice, the down-regulation of Th1 (IFNγ) and pro-inflammatory cytokines (TNFα and IL-17A), and up-regulation of Th2 (IL-4) and an anti-inflammatory cytokine (IL-10) were observed. In addition, real-time PCR revealed that the augmentation of pro-inflammatory mediators such as IL-1β, IL-6 and receptor activator of NFκB in inflamed paws was abrogated by S. mansoni infection. In conclusion, schistosome infection reduced the severity of autoimmune arthritis via systemic and local suppression of pro-inflammatory mediators, suggesting the potential of parasite-derived materials as therapeutic agents against rheumatoid arthritis.

Semliki Forest virus infection is enhanced in Th1-prone SJL mice but not in Th2-prone BALB/c mice during Linomide-induced immunomodulation

Linomide (quinoline-3-carboxamide) is an immunomodulator with diverse effects on the immune system. Its beneficial effects on experimental autoimmune disease models have been linked to downregulation of Th1 cytokines and altered macrophage functions. We studied this effect of downregulation of Th1-type of immune response on Semliki Forest A7 virus infection in experimental autoimmune encephalomyelitis (EAE) susceptible Th1-prone SJL mice and in EAE-resistant Th2-prone BALB/c mice. We aimed at addressing the target-cell population of Linomide responsible for this Th1 downregulation. Treatment with Linomide led to increased virus infection in brain and this effect coincided with decreased production of IL-12 and IFN-γ from stimulated spleen cells in SJL mice. In contrast, IL-12 and IFN-γ expression were increased in Linomide-treated BALB/c mice. Treatment of infected SJL mice resulted in decreased percentage of CD11b+ and CD11c+ cells. Thus, the target cell population of Linomide may be antigen-presenting cells (APC) which are considered as candidates for regulatory cells of Th1/Th2 balance.

Th1 down-regulation at the single-lymphocyte level in HCV-related liver cirrhosis and the effect of TGF-β on Th1 response: possible implications for the development of hepatoma

Patients with hepatitis C virus (HCV) related-liver cirrhosis (LC) often develop hepatoma. The type 1 helper T cell (Th1) response presents an antitumor effect. We evaluated the Th1 response in patients with HCV-related LC at the single-cell level and examined the influence of transforming growth factor (TGF)-β, an immunosuppressive cytokine, on the Th1 response. We determined the ratios of Th1-type cytokine (IFN-γ, IL-2)-producing cells to CD3-positive cells in 14 patients (LC group) and in 16 normal controls using flow cytometry and measured serum TGF-β 1 and TGF-β 2 levels by ELISA. We then incubated, peripheral blood mononuclear cells from seven healthy volunteers with recombinant TGF-β 1 or TGF-β 2 for 48 h, and determined the ratio of IFN-γ producing cells to CD3-positive cells. The IFN-γ ratio was significantly lower in the LC group (29.7±0.3 vs. 44.2±15.0%, P<0.01). The serum TGF-β 2 level was significantly increased in the LC group (601±232 vs. 329±118 pg/ml, P<0.001). TGF-β 2 significantly suppressed IFN-γ production at the single-cell level (10.0±4.3 vs. 7.3±2.0%, P<0.05). These findings indicated that the enhanced down-regulation of Th1 by TGF-β 2 in patients with HCV-related LC might be effective against hepatoma.

Th1 and Th2 cytokine responses to academic stress.

Predominant Th2 profiles are associated with the worsening of asthma, and stress is speculated to induce a Th2 profile. The goals of this study were to examine the responses of the cytokines Th1 (IFN-gamma and IL-2) and Th2 (IL-4, IL-5, and IL-6) to a stressor and to look at the relationships between cytokine and psychological responses. Twenty-four students with and without a history of asthma completed questionnaires and gave blood samples during nonexam and exam periods. Cytokines were measured by ELISA from supernatants of stimulated mononuclear cells (MNC) and whole blood. During examinations, there were a significant decrease in IL-2 and a significant increase in IL-6 production (both cultures) and a significant decrease in IFN-gamma production (MNC cultures). Baseline IL-2 levels showed significant negative correlations with several stress and mood scores. Findings of this study indicate a down-regulation of Th1 and a selective up-regulation of Th2 cytokines during a stressful exposure.

Oligosaccharide-specific induction of interleukin 10 production by B220+ cells from schistosome-infected mice: a mechanism for regulation of CD4+ T-cell subsets.

Defining the factors and/or mechanisms that lead to the predominance of a particular CD4+ T-cell subset (Th-1 vs. Th-2) is an area of intense investigation. In murine schistosomiasis, Th-2-type T cells become predominant after deposition of eggs. The most immunoreactive egg components are glycoproteins. Previously we identified two interesting oligosaccharides found on schistosome eggs and schistosomula. One, lacto-N-fucopentaose III (LNFP-III) contains the interesting trisaccharide Lewisx, which is a weak ligand for P-selectin and is a sugar also found on the alpha and beta chains of the integrin lymphocyte function-associated molecule 1, a ligand for intercellular adhesion molecule 1. Because of the correlation between schistosome egg glycoproteins and Th-2 dominance, the present study examined whether LNFP-III and structurally related oligosaccharides were lymphostimulatory and/or able to induce factors known to down-regulate Th-1 cells. We found that LNFP-III and related sugars did induce proliferation of splenic non-T cells, B220+,CD4-,CD8- cells (B cells) of schistosome-infected and naive mice. In contrast to proliferation, LNFP-III was the only oligosaccharide that induced spleen cells to produce large amounts of interleukin 10 and prostaglandin E2, two molecules known to down-regulate Th-1 cells. Further, only spleen cells from infected mice produced cytokines after oligosaccharide stimulation. Interestingly, LNFP-III stimulation did not induce production of interleukin 4. Thus, a specific carbohydrate ligand has been identified that stimulates B cells to proliferate and produce factors that down-regulate Th-1 T cells. Further, we suggest that identical or structurally related ligands may contribute to the known Th-1 down-regulation in other parasitic diseases and in chronic blood-vascular diseases such as human immunodeficiency virus infection and a number of metastatic carcinomas and that this effect may, therefore, be a general phenomenon.