Enhanced B7-2 Gene Expression by Interferon-γ in Human Monocytic Cells Is Controlled Through Transcriptional and Posttranscriptional Mechanisms

Blood ◽  
1999 ◽  
Vol 94 (5) ◽  
pp. 1782-1789 ◽  
Author(s):  
R.E. Curiel ◽  
C.S. Garcia ◽  
S. Rottschafer ◽  
M.C. Bosco ◽  
I. Espinoza-Delgado
Keyword(s):  
T Cell Activation ◽  
Cell Activation ◽  
Molecular Mechanisms ◽  
De Novo ◽  
Costimulatory Molecule ◽  
Interferon Γ ◽  
Monocytic Cell ◽  
Monocytic Cells ◽  
Enhanced Expression ◽  
Ifn Γ

B7-2 is a costimulatory molecule expressed on professional antigen-presenting cells that provides T cells with a critical signal resulting in T-cell activation. Interferon-γ (IFN-γ) enhances B7-2 protein expression in monocytic cells. However, the molecular mechanisms controlling the enhanced expression of B7-2 are poorly understood. Northern blot and flow cytometry analysis revealed that human monocytes and the human monocytic cell line MonoMac6 (MM6) constitutively expressed B7-2 mRNA and protein and IFN-γ treatment further enhanced the expression of both molecules. The ability of IFN-γ to enhance B7-2 mRNA was evident at the dose of 31 U/mL and reached plateau levels at 500 U/mL. The effects of IFN-γ on B7-2 mRNA expression were time dependent and occurred within 3 hours of treatment and increased through 24 hours. In vitro transcription assays and mRNA stability experiments showed that IFN-γ increases both transcriptional activity and the stability of B7-2 mRNA. Treatment of MM6 cells with cycloheximide showed that de novo protein synthesis was not required for the IFN-γ–enhanced expression of B7-2 mRNA. Overall, these studies show for the first time that IFN-γ–enhanced expression of B7-2 protein in human monocytic cells is controlled at the gene level through a dual mechanism involving transcriptional and posttranscriptional mechanisms.

Enhanced B7-2 Gene Expression by Interferon-γ in Human Monocytic Cells Is Controlled Through Transcriptional and Posttranscriptional Mechanisms

Blood ◽  
1999 ◽  
Vol 94 (5) ◽  
pp. 1782-1789 ◽  
Author(s):  
R.E. Curiel ◽  
C.S. Garcia ◽  
S. Rottschafer ◽  
M.C. Bosco ◽  
I. Espinoza-Delgado
Keyword(s):  
T Cell Activation ◽  
Cell Activation ◽  
Molecular Mechanisms ◽  
De Novo ◽  
Costimulatory Molecule ◽  
Interferon Γ ◽  
Monocytic Cell ◽  
Monocytic Cells ◽  
Enhanced Expression ◽  
Ifn Γ

Abstract B7-2 is a costimulatory molecule expressed on professional antigen-presenting cells that provides T cells with a critical signal resulting in T-cell activation. Interferon-γ (IFN-γ) enhances B7-2 protein expression in monocytic cells. However, the molecular mechanisms controlling the enhanced expression of B7-2 are poorly understood. Northern blot and flow cytometry analysis revealed that human monocytes and the human monocytic cell line MonoMac6 (MM6) constitutively expressed B7-2 mRNA and protein and IFN-γ treatment further enhanced the expression of both molecules. The ability of IFN-γ to enhance B7-2 mRNA was evident at the dose of 31 U/mL and reached plateau levels at 500 U/mL. The effects of IFN-γ on B7-2 mRNA expression were time dependent and occurred within 3 hours of treatment and increased through 24 hours. In vitro transcription assays and mRNA stability experiments showed that IFN-γ increases both transcriptional activity and the stability of B7-2 mRNA. Treatment of MM6 cells with cycloheximide showed that de novo protein synthesis was not required for the IFN-γ–enhanced expression of B7-2 mRNA. Overall, these studies show for the first time that IFN-γ–enhanced expression of B7-2 protein in human monocytic cells is controlled at the gene level through a dual mechanism involving transcriptional and posttranscriptional mechanisms.

scholarly journals Interleukin 12 (IL-12) Is Crucial to the Development of Protective Immunity in Mice Intravenously Infected with Mycobacterium tuberculosis

1997 ◽  
Vol 186 (1) ◽  
pp. 39-45 ◽  
Author(s):  
Andrea M. Cooper ◽  
Jeanne Magram ◽  
Jessica Ferrante ◽  
Ian M. Orme
Keyword(s):  
Immune Response ◽  
Mycobacterium Tuberculosis ◽  
T Cell Activation ◽  
Bacterial Growth ◽  
Cell Activation ◽  
Interferon Γ ◽  
Delayed Type Hypersensitivity ◽  
Interleukin 12 ◽  
Mycobacterium Tuberculosis Infection ◽  
Ifn Γ

Immunity to Mycobacterium tuberculosis infection is associated with the emergence of protective CD4 T cells that secrete cytokines, resulting in activation of macrophages and the recruitment of monocytes to initiate granuloma formation. The cytokine-mediating macrophage activation is interferon-γ (IFN-γ), which is largely dependent on interleukin-12 (IL-12) for its induction. To address the role of IL-12 in immunity to tuberculosis, IL-12 p40−/− mice were infected with M. tuberculosis and their capacity to control bacterial growth and other characteristics of their immune response were determined. The IL-12 p40−/− mice were unable to control bacterial growth and this appeared to be linked to the absence of both innate and acquired sources of IFN-γ. T cell activation as measured by delayed type hypersensitivity and lymphocyte accumulation at the site of infection were both markedly reduced in the IL-12 p40−/− mice. Therefore, IL-12 is essential to the generation of a protective immune response to M. tuberculosis, with its main functions being the induction of the expression of IFN-γ and the activation of antigen-specific lymphocytes capable of creating a protective granuloma.

scholarly journals Increased state of activation of CD4 positive T cells and elevated interferon γ production in pouchitis

Gut ◽  
1998 ◽  
Vol 43 (4) ◽  
pp. 499-505 ◽  
Author(s):  
A Stallmach ◽  
F Schäfer ◽  
S Hoffmann ◽  
S Weber ◽  
I Müller-Molaian ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
T Cell Activation ◽  
Cell Activation ◽  
Mononuclear Cells ◽  
Interferon Γ ◽  
Ileoanal Pouch ◽  
T Cell Subsets ◽  
Activation Markers ◽  
Ifn Γ

Background—Immunoregulatory abnormalities of T cells might be of importance in the pathogenesis of pouchitis after ileoanal pouch anastomosis (IAP).Aims—To characterise T cell subsets, their state of activation, and production of cytokines in inflamed and non-inflamed pouches in patients with ulcerative colitis (UC) and familial adenomatous polyposis (FAP). The influence of T cell activation on mucosal transformation was also studied.Patients—Mucosal biopsy specimens were taken from 42 patients with IAP (33 with UC and nine with FAP).Methods—Mononuclear cells were isolated by standard techniques and characterised by three colour flow cytometry. Interferon γ (IFN-γ) production was studied using the ELISPOT technique.Results—In patients with UC with pouchitis there was a significant increase in the CD4:CD8 ratio, expression of activation markers on CD3+ cells, and number of IFNγ producing mononuclear cells compared with patients with UC without pouchitis (CD4:CD8 ratio 1.3 (range 0.7–2.7) versus 0.6 (0.1–1.0), p=0.012). In addition, a positive correlation between increased crypt depth and the number of CD4+ cells (r=0.57) was shown.Conclusion—The observed increase in activated mucosal CD4+ T cells and IFN-γ production might lead to mucosal destruction and crypt hyperplasia as seen in pouchitis.

Humulus scandens Exhibits Immunosuppressive Effects in Vitro and in Vivo by Suppressing CD4+ T Cell Activation

2014 ◽  
Vol 42 (04) ◽  
pp. 921-934 ◽  
Author(s):  
Jinjin Feng ◽  
Yingchun Wu ◽  
Yang Yang ◽  
Weiqi Jiang ◽  
Shaoping Hu ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
T Cell Activation ◽  
Cell Activation ◽  
Interferon Γ ◽  
Delayed Type Hypersensitivity ◽  
Ifn Γ ◽  
Humulus Scandens

Humulus scandens, rich in flavonoids, is a traditional Chinese medicine. It is widely used in China to treat tuberculosis, dysentery and chronic colitis. In this study, the major active faction of Humulus scandens (H.S) was prepared. Then, its immunosuppressive effects and underlying mechanisms on T cell activation were investigated in vitro and in vivo. Results showed that H.S significantly inhibited the proliferation of splenocytes induced by concanavalin A, lipopolysaccharides, and mixed-lymphocyte reaction in vitro. Additionally, H.S could dramatically suppress the proliferation and interferon-γ (IFN-γ) production from T cells stimulated by anti-CD3 and anti-CD28. Flow cytometric results confirmed that H.S could suppress the differentiation of IFN-γ-producing type 1 helper T cells (Th1). Furthermore, using ovalbumin immunization-induced T cell reaction and CD4+ T-cell-mediated delayed type hypersensitivity reaction, H.S the immunosuppressive effects of H.S was also demonstrated in vivo. Western blot results showed that H.S could impede the activation of both Erk1/2 and P38 in primary T cells triggered by anti-CD3/28. Collectively, the active fraction of H.S showed promising immunosuppressive activities both in vitro and in vivo.

B7-H3: A costimulatory molecule for T cell activation and IFN-γ production

10.1038/85339 ◽  
2001 ◽  
Vol 2 (3) ◽  
pp. 269-274 ◽  
Author(s):  
Andrei I. Chapoval ◽  
Jian Ni ◽  
Julie S. Lau ◽  
Ryan A. Wilcox ◽  
Dallas B. Flies ◽  
...  
Keyword(s):  
T Cell ◽  
T Cell Activation ◽  
Cell Activation ◽  
Costimulatory Molecule ◽  
Ifn Γ

scholarly journals Mechanisms of action of ruxolitinib in murine models of hemophagocytic lymphohistiocytosis

Blood ◽  
2019 ◽  
Vol 134 (2) ◽  
pp. 147-159 ◽  
Author(s):  
Sabrin Albeituni ◽  
Katherine C. Verbist ◽  
Paige E. Tedrick ◽  
Heather Tillman ◽  
Jennifer Picarsic ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell Activation ◽  
Proinflammatory Cytokines ◽  
Hemophagocytic Lymphohistiocytosis ◽  
Cell Activation ◽  
Neutralizing Antibody ◽  
Interferon Γ ◽  
Lymphocytic Choriomeningitis ◽  
Dependent Manner ◽  
Ifn Γ

Abstract Hemophagocytic lymphohistiocytosis (HLH) is an often-fatal disorder characterized by the overactivation of T cells and macrophages that excessively produce proinflammatory cytokines, including interferon-γ (IFN-γ). Previously, we reported that the JAK inhibitor ruxolitinib dampens T-cell activation and lessens inflammation in a model of HLH in which perforin-deficient (Prf1−/−) mice are infected with lymphocytic choriomeningitis virus (LCMV). Ruxolitinib inhibits signaling downstream of IFN-γ, as well as several other JAK-dependent cytokines. As a consequence, it remained unclear whether ruxolitinib was exerting its beneficial effects in HLH by inhibiting IFN-γ signaling or by targeting signaling initiated by other proinflammatory cytokines. To address this question, we compared the effects of ruxolitinib with those obtained using an IFN-γ–neutralizing antibody (αIFN-γ) in 2 murine HLH models. In both models, ruxolitinib and αIFN-γ reduced inflammation-associated anemia, indicating that ruxolitinib operates in an IFN-γ–dependent manner to reverse this HLH manifestation. In contrast, the number and activation status of T cells and neutrophils, as well as their infiltration into tissues, were significantly reduced following treatment with ruxolitinib, but they remained unchanged or were increased following treatment with αIFN-γ. Notably, despite discontinuation of ruxolitinib, LCMV-infected Prf1−/− mice exhibited enhanced survival compared with mice in which αIFN-γ was discontinued. This protective effect could be mimicked by transient treatment with αIFN-γ and a neutrophil-depleting antibody. Thus, ruxolitinib operates through IFN-γ–dependent and -independent mechanisms to dampen HLH by targeting the deleterious effects of T cells and neutrophils, with the latter representing an unappreciated and understudied cell type that contributes to HLH pathogenesis.

Paradoxical Effects of Interferon-γ in Allogeneic Bone Marrow Transplant: Donor Dendritic Cells Regulate Graft-Versus-Leukemia and Graft- Versus-Host Disease Activities.

Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 2343-2343
Author(s):  
Ying Lu ◽  
Jian-Ming Li ◽  
Wayne Harris ◽  
Edmund Waller
Keyword(s):  
Bone Marrow ◽  
T Cells ◽  
T Cell ◽  
T Cell Activation ◽  
Cell Activation ◽  
Interferon Γ ◽  
Wild Type ◽  
Graft Versus Host ◽  
Donor T Cells ◽  
Ifn Γ

Abstract Both host and donor dendritic cells (DCs) have been shown to play a critical role in regulating graft-versus-host disease (GVHD) and graft-versus-leukemia (GVL) effect after MHC-mismatched bone marrow transplantation (BMT) (Shlomchik et al. Science 1999, Reddy et al. Nat Med 2005). In contrast to host DCs, much less is known about the precise mechanisms donor DCs may use to modulate donor T-cell activation and GVL activity. A clinical report has suggested an association between the number of donor plasmacytoid DC in the graft and leukemia relapses after allogeneic BMT (Waller et al. Blood 2001). Using allogeneic MHC-mismatched hematopoietic stem cell transplant (HSCT) (C57BL/6→B10.BR) in mice bearing the T lymphoblastic leukemia LBRM, we have previously reported that recipients transplanted with purified CD11b− DC in combination with purified HSC and T-cells had 45% increased long-term leukemia-free-survival, higher numbers of interferon-γ (IFN-γ) producing donor T-cells as well as higher levels of serum IFN-γ (Li et al. Blood 2007). The aim of the present work is to further define whether production of IFN-γ by donor T-cells is necessary for the augmentation of GVL effect seen with CD11b− donor DC and define the mechanism that donor CD11b− DC can augment GVL of donor T-cells without causing fatal GVHD. To evaluate the role for IFN-γ produced by donor T-cells, we used IFN-γ knockout (KO) mice as donors in the C57BL/6→B10.BR transplant model. Recipients of IFN-γ KO donor T-cells in combination with wild-type FACS-purified HSC and CD11b− DC died rapidly with 0% survival at day 80 compared with 65% survival among tumor-bearing recipients of donor CD11b− with wild-type HSC and T-cells and 75% survival in mice transplanted with wild-type cells in the absence of LBRM. Moreover, the addition of donor CD11b− DC to IFN-γ KO donor T-cells did not lead to further augmentation of GVHD. These data supported a role for donor T-cell-derived IFN-γ in the enhanced GVL activity seen among recipients of donor CD11b− DC,but did not explain the lack of increased GVHD. As a potent pro-inflammatory cytokine initiating immune response in GVHD, IFN-γ has also been demonstrated to show a suppressive effect during GVHD as a result of IFN-γ-inducible indoleamine-2,3-dioxygenase(IDO) gene expression. CD11b− DCs were freshly isolated from bone marrow of donor C57BL/6 mice, exposed to 100ng/ml IFN-γ for 18 hours, and the IDO expression was measured by intracellular staining. The results showed that following IFN-γ treatment, IDO levels of CD11b− DCs were up-regulated. Furthermore, in vitro co-culture of FACS-purified CD11b− DC with syngeneic T-cells in the presence of allogeneic antigen also demonstrated increased IDO levels on the co-cultured DCs. Taken together, our data support a model in which donor CD11b− DCs initially induce Th1 polarization of activated donor T-cells that secret high levels of IFN-γ in the lymph node microenvironment. High local levels of IFN-γ subsequently induce IDO expression in DC, resulting in down-modulation of T-cell allo-reactivity and GVHD. Thus, IFN-γ-induced IDO expression on CD11b− donor DCs appears to be a critical downstream event that inhibits continued T-cell activation and leads to less severe GVHD.

scholarly journals A Novel Kinase Inhibitor AX-0085 Inhibits Interferon-γ-Mediated Induction of PD-L1 Expression and Promotes Immune Reaction to Lung Adenocarcinoma Cells

Cells ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 19
Author(s):  
Jusong Kim ◽  
Haeyeon Jang ◽  
Gyu Jin Lee ◽  
Yelim Hur ◽  
Juhee Keum ◽  
...  
Keyword(s):  
T Cell ◽  
Lung Adenocarcinoma ◽  
T Cell Activation ◽  
Cell Activation ◽  
Kinase Inhibitor ◽  
Interferon Γ ◽  
Adenocarcinoma Cells ◽  
Ifn Γ

In this study, we describe a novel kinase inhibitor AX-0085 which can suppress the induction of PD-L1 expression by Interferon-γ (IFN-γ) in lung adenocarcinoma (LUAD) cells. AX-0085 effectively blocks JAK2/STAT1 signaling initiated by IFN-γ treatment and prevents nuclear localization of STAT1. Importantly, we demonstrate that AX-0085 reverses the IFN-γ-mediated repression of T cell activation in vitro and enhances the anti-tumor activity of anti-PD-1 antibody in vivo when used in combination. Finally, transcriptomic analyses indicated that AX-0085 is highly specific in targeting the IFN-γ-pathway, thereby raising the possibility of applying this reagent in combination therapy with checkpoint inhibitor antibodies. It may be particularly relevant in cases in which PD-L1-mediated T cell exhaustion leads to immunoevasive phenotypes.

scholarly journals CCL19 enhances CD8+ T-cell responses and accelerates HBV clearance

2021 ◽  
Author(s):  
Yan Yan ◽  
Wei Zhao ◽  
Wei Liu ◽  
Yan Li ◽  
Xu Wang ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
T Cell Activation ◽  
Crucial Role ◽  
Cell Activation ◽  
Hbv Infection ◽  
Host Immune System ◽  
Tnf Α ◽  
Ifn Γ ◽  
High Level

Abstract Background Chemokine (C–C motif) ligand 19 (CCL19) is a leukocyte chemoattractant that plays a crucial role in cell trafficking and leukocyte activation. Dysfunctional CD8+ T cells play a crucial role in persistent HBV infection. However, whether HBV can be cleared by CCL19-activated immunity remains unclear. Methods We assessed the effects of CCL19 on the activation of PBMCs in patients with HBV infection. We also examined how CCL19 influences HBV clearance and modulates HBV-responsive T cells in a mouse model of chronic hepatitis B (CHB). In addition, C–C chemokine-receptor type 7 (CCR7) knockdown mice were used to elucidate the underlying mechanism of CCL19/CCR7 axis-induced immune activation. Results From in vitro experiments, we found that CCL19 enhanced the frequencies of Ag-responsive IFN-γ+ CD8+ T cells from patients by approximately twofold, while CCR7 knockdown (LV-shCCR7) and LY294002 partially suppressed IFN-γ secretion. In mice, CCL19 overexpression led to rapid clearance of intrahepatic HBV likely through increased intrahepatic CD8+ T-cell proportion, decreased frequency of PD-1+ CD8+ T cells in blood and compromised suppression of hepatic APCs, with lymphocytes producing a significantly high level of Ag-responsive TNF-α and IFN-γ from CD8+ T cells. In both CCL19 over expressing and CCR7 knockdown (AAV-shCCR7) CHB mice, the frequency of CD8+ T-cell activation-induced cell death (AICD) increased, and a high level of Ag-responsive TNF-α and low levels of CD8+ regulatory T (Treg) cells were observed. Conclusions Findings in this study provide insights into how CCL19/CCR7 axis modulates the host immune system, which may promote the development of immunotherapeutic strategies for HBV treatment by overcoming T-cell tolerance.

scholarly journals Immune Restoration Diseases Reflect Diverse Immunopathological Mechanisms

2009 ◽  
Vol 22 (4) ◽  
pp. 651-663 ◽  
Author(s):  
Patricia Price ◽  
David M. Murdoch ◽  
Upasna Agarwal ◽  
Sharon R. Lewin ◽  
Julian H. Elliott ◽  
...  
Keyword(s):  
T Cell ◽  
Immune Responses ◽  
T Cell Activation ◽  
Cell Activation ◽  
De Novo ◽  
Granulomatous Inflammation ◽  
T Cell Response ◽  
Immune Restoration ◽  
Immunological Parameters ◽  
Varicella Zoster

SUMMARY Up to one in four patients infected with human immunodeficiency virus type 1 and given antiretroviral therapy (ART) experiences inflammatory or cellular proliferative disease associated with a preexisting opportunistic infection, which may be subclinical. These immune restoration diseases (IRD) appear to result from the restoration of immunocompetence. IRD associated with intracellular pathogens are characterized by cellular immune responses and/or granulomatous inflammation. Mycobacterial and cryptococcal IRD are attributed to a pathological overproduction of Th1 cytokines. Clinicopathological characteristics of IRD associated with viral infections suggest different pathogenic mechanisms. For example, IRD associated with varicella-zoster virus or JC polyomavirus infection correlate with a CD8 T-cell response in the central nervous system. Exacerbations or de novo presentations of hepatitis associated with hepatitis C virus (HCV) infection following ART may also reflect restoration of pathogen-specific immune responses as titers of HCV-reactive antibodies rise in parallel with liver enzymes and plasma markers of T-cell activation. Correlations between immunological parameters assessed in longitudinal sample sets and clinical presentations are required to illuminate the diverse immunological scenarios described collectively as IRD. Here we present salient clinical features and review progress toward understanding their pathogeneses.

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