Areca nut extract suppresses T-cell activation and interferon-γ production via the induction of oxidative stress

2007 ◽  
Vol 45 (8) ◽  
pp. 1410-1418 ◽  
Author(s):  
C.C. Wang ◽  
T.Y. Liu ◽  
S.P. Wey ◽  
F.I. Wang ◽  
T.R. Jan
Keyword(s):  
Oxidative Stress ◽  
T Cell ◽  
T Cell Activation ◽  
Cell Activation ◽  
Interferon Γ ◽  
Areca Nut

scholarly journals SLFN2 protection of tRNAs from stress-induced cleavage is essential for T cell–mediated immunity

Science ◽  
2021 ◽  
Vol 372 (6543) ◽  
pp. eaba4220 ◽  
Author(s):  
Tao Yue ◽  
Xiaoming Zhan ◽  
Duanwu Zhang ◽  
Ruchi Jain ◽  
Kuan-wen Wang ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
T Cells ◽  
T Cell ◽  
T Cell Activation ◽  
Cell Activation ◽  
Interleukin 2 ◽  
Cell Receptor ◽  
Cell Mediated Immunity ◽  
Activated T Cells ◽  
Granule Formation

Reactive oxygen species (ROS) increase in activated T cells because of metabolic activity induced to support T cell proliferation and differentiation. We show that these ROS trigger an oxidative stress response that leads to translation repression. This response is countered by Schlafen 2 (SLFN2), which directly binds transfer RNAs (tRNAs) to protect them from cleavage by the ribonuclease angiogenin. T cell–specific SLFN2 deficiency results in the accumulation of tRNA fragments, which inhibit translation and promote stress-granule formation. Interleukin-2 receptor β (IL-2Rβ) and IL-2Rγ fail to be translationally up-regulated after T cell receptor stimulation, rendering SLFN2-deficient T cells insensitive to interleukin-2’s mitogenic effects. SLFN2 confers resistance against the ROS-mediated translation-inhibitory effects of oxidative stress normally induced by T cell activation, permitting the robust protein synthesis necessary for T cell expansion and immunity.

Molecular transfer of CD40 and OX40 ligands to leukemic human B cells induces expansion of autologous tumor–reactive cytotoxic T lymphocytes

Blood ◽  
2005 ◽  
Vol 105 (6) ◽  
pp. 2436-2442 ◽  
Author(s):  
Ettore Biagi ◽  
Gianpietro Dotti ◽  
Eric Yvon ◽  
Edward Lee ◽  
Martin Pule ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
T Cell Activation ◽  
Cell Activation ◽  
Antibody Therapy ◽  
Interferon Γ ◽  
Lymphocytic Leukemia ◽  
Cytotoxic T Cell ◽  
Autologous Tumor ◽  
Molecular Transfer

AbstractClinical benefits from monoclonal antibody therapy for B-chronic lymphocytic leukemia (B-CLL) have increased interest in developing additional immunotherapies for the disease. CD40 ligand is an accessory signal for T-cell activation and can overcome T-cell anergy. The OX40-OX40 ligand pathway is involved in the subsequent expansion of memory antigen-specific T cells. We expressed both CD40L and OX40L on B-CLL cells by exploiting the phenomenon of molecular transfer from fibroblasts overexpressing these ligands. We analyzed the effects of the modified B-CLL cells on the number, phenotype, and cytotoxic function of autologous T cells in 7 B-CLL patients. Transfer of CD40L and OX40L was observed in all and was followed by the up-regulation of B7-1 and B7-2. The culture of CD40L/OX40L-expressing B-CLL cells with autologous T cells generated CD4+/CD8+ cytotoxic T-cell lines, which secreted interferon-γ (IFN-γ) and granzyme-B/perforin in response to autologous, but not to allogeneic, B-CLL cells or to autologous T-cell blasts. CD40L or OX40L alone was insufficient to expand tumor-reactive T cells. The combination of CD40L and OX40L on B-CLL cells may allow the generation of therapeutic immune responses to B-CLL, either by active immunization with modified tumor cells or by adoptive immunotherapy with tumor-reactive autologous T cells.

Intravenous immunoglobulins suppress T-cell priming by modulating the bidirectional interaction between dendritic cells and natural killer cells

Blood ◽  
2007 ◽  
Vol 110 (9) ◽  
pp. 3253-3262 ◽  
Author(s):  
Thanyalak Tha-In ◽  
Herold J. Metselaar ◽  
Hugo W. Tilanus ◽  
Zwier M. A. Groothuismink ◽  
Ernst J. Kuipers ◽  
...  
Keyword(s):  
Dendritic Cells ◽  
T Cell ◽  
Nk Cells ◽  
T Cell Activation ◽  
Cell Activation ◽  
Nk Cell ◽  
Intravenous Immunoglobulins ◽  
Interferon Γ ◽  
T Cell Priming ◽  
Induced Apoptosis

AbstractThe modes of action of intravenous immunoglobulins (IVIgs) in exerting their immunomodulatory properties are broad and not fully understood. IVIgs can modulate the function of various immune cells, including suppressing the capacity of dendritic cells (DCs) to stimulate T cells. In the present study, we showed that DCs matured in the presence of IVIgs (IVIg-DCs) activated NK cells, and increased their interferon-γ production and degranulation. The activated NK cells induced apoptosis of the majority of IVIg-DCs. In consequence, only in the presence of NK cells, IVIg-DCs were 4-fold impaired in their T-cell priming capacity. This was due to NK-cell–mediated antibody-dependent cellular cytotoxicity (ADCC) to IVIg-DCs, probably induced by IgG multimers, which could be abrogated by blockade of CD16 on NK cells. Furthermore, IVIg-DCs down-regulated the expression of NKp30 and KIR receptors, and induced the generation of CD56brightCD16−CCR7+ lymph node–type NK cells. Our results identify a novel pathway, in which IVIgs induce ADCC of mature DCs by NK cells, which downsizes the antigen-presenting pool and inhibits T-cell priming. By influencing the interaction between DCs and NK cells, IVIgs modulate the ability of the innate immunity to trigger T-cell activation, a mechanism that can “cool down” the immune system at times of activation.

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.

scholarly journals Dendritic Cells Induce Peripheral T Cell Unresponsiveness under Steady State Conditions in Vivo

2001 ◽  
Vol 194 (6) ◽  
pp. 769-780 ◽  
Author(s):  
Daniel Hawiger ◽  
Kayo Inaba ◽  
Yair Dorsett ◽  
Ming Guo ◽  
Karsten Mahnke ◽  
...  
Keyword(s):  
T Cells ◽  
Dendritic Cells ◽  
Steady State ◽  
T Cell ◽  
T Cell Activation ◽  
Cell Activation ◽  
Interferon Γ ◽  
Peripheral Tolerance ◽  
Antigen Delivery

Dendritic cells (DCs) have the capacity to initiate immune responses, but it has been postulated that they may also be involved in inducing peripheral tolerance. To examine the function of DCs in the steady state we devised an antigen delivery system targeting these specialized antigen presenting cells in vivo using a monoclonal antibody to a DC-restricted endocytic receptor, DEC-205. Our experiments show that this route of antigen delivery to DCs is several orders of magnitude more efficient than free peptide in complete Freund's adjuvant (CFA) in inducing T cell activation and cell division. However, T cells activated by antigen delivered to DCs are not polarized to produce T helper type 1 cytokine interferon γ and the activation response is not sustained. Within 7 d the number of antigen-specific T cells is severely reduced, and the residual T cells become unresponsive to systemic challenge with antigen in CFA. Coinjection of the DC-targeted antigen and anti-CD40 agonistic antibody changes the outcome from tolerance to prolonged T cell activation and immunity. We conclude that in the absence of additional stimuli DCs induce transient antigen-specific T cell activation followed by T cell deletion and unresponsiveness.

Effect of interferon-γ on the abnormality of T cell activation in NZB mice

1988 ◽  
Vol 49 (2) ◽  
pp. 283-291 ◽  
Author(s):  
Masahide Minoda ◽  
Masanori Funauchi ◽  
Atsushi Horiuchi
Keyword(s):  
T Cell ◽  
T Cell Activation ◽  
Cell Activation ◽  
Interferon Γ
Sign in / Sign up

Export Citation Format

Share Document