scholarly journals HTLV-1 ORF-I Encoded Proteins and the Regulation of Host Immune Response: Viral Induced Dysregulation of Intracellular Signaling

2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
Carolina Rosadas ◽  
Marzia Puccioni-Sohler
Keyword(s):  
Immune Response ◽  
Cell Proliferation ◽  
T Cell ◽  
Intracellular Signaling ◽  
Molecular Mechanisms ◽  
T Cell Proliferation ◽  
Human T Cell ◽  
Encoded Proteins ◽  
Infected Cells ◽  
The Impact

The human T-cell lymphotropic virus type 1 (HTLV-1) is a retrovirus associated with both proliferative and inflammatory disorders. This virus causes a persistent infection, mainly in CD4+ T lymphocyte. The ability to persist in the host is associated with the virus capacity to evade the immune response and to induce infected T-cell proliferation, once the HTLV-1 maintains the infection mainly by clonal expansion of infected cells. There are several evidences that ORF-I encoded proteins, such as p12 and p8, play an important role in this context. The present study will review the molecular mechanisms that HTLV-1 ORF-I encoded proteins have to induce dysregulation of intracellular signaling, in order to escape from immune response and to increase the infected T-cell proliferation rate. The work will also address the impact of ORF-I mutations on the human host and perspectives in this study field.

scholarly journals Keratinocytes Regulate the Threshold of Inflammation by Inhibiting T Cell Effector Functions

Cells ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 1606
Author(s):  
Peter Seiringer ◽  
Stefanie Eyerich ◽  
Kilian Eyerich ◽  
Daniela Dittlein ◽  
Anna Caroline Pilz ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
T Cell ◽  
Cytokine Production ◽  
Nickel Sulfate ◽  
Human Keratinocytes ◽  
T Cell Proliferation ◽  
Effector Functions ◽  
The Impact ◽  
Cell Effector

Whilst the importance of keratinocytes as a first-line defense has been widely investigated, little is known about their interactions with non-resident immune cells. In this study, the impact of human keratinocytes on T cell effector functions was analyzed in an antigen-specific in vitro model of allergic contact dermatitis (ACD) to nickel sulfate. Keratinocytes partially inhibited T cell proliferation and cytokine production. This effect was dependent on the keratinocyte/T cell ratio and was partially reversible by increasing the number of autologous dendritic cells. The inhibition of T cell proliferation by keratinocytes was independent of the T cell subtype and antigen presentation by different professional antigen-presenting cells. Autologous and heterologous keratinocytes showed comparable effects, while the fixation of keratinocytes with paraformaldehyde abrogated the immunosuppressive effect. The separation of keratinocytes and T cells by a transwell chamber, as well as a cell-free keratinocyte supernatant, inhibited T cell effector functions to the same amount as directly co-cultured keratinocytes, thus proving that soluble factor/s account for the observed suppressive effects. In conclusion, keratinocytes critically control the threshold of inflammatory processes in the skin by inhibiting T cell proliferation and cytokine production.

Nitric oxide plays a critical role in suppression of T-cell proliferation by mesenchymal stem cells

Blood ◽  
2006 ◽  
Vol 109 (1) ◽  
pp. 228-234 ◽  
Author(s):  
Kazuya Sato ◽  
Katsutoshi Ozaki ◽  
Iekuni Oh ◽  
Akiko Meguro ◽  
Keiko Hatanaka ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Stem Cells ◽  
Cell Proliferation ◽  
T Cells ◽  
Mesenchymal Stem Cells ◽  
T Cell ◽  
Molecular Mechanisms ◽  
Critical Role ◽  
Specific Inhibitor ◽  
T Cell Proliferation

Abstract The molecular mechanisms by which mesenchymal stem cells (MSCs) suppress T-cell proliferation are poorly understood, and whether a soluble factor plays a major role remains controversial. Here we demonstrate that the T-cell–receptor complex is not a target for the suppression, suggesting that downstream signals mediate the suppression. We found that Stat5 phosphorylation in T cells is suppressed in the presence of MSCs and that nitric oxide (NO) is involved in the suppression of Stat5 phosphorylation and T-cell proliferation. The induction of inducible NO synthase (NOS) was readily detected in MSCs but not T cells, and a specific inhibitor of NOS reversed the suppression of Stat5 phosphorylation and T-cell proliferation. This production of NO in the presence of MSCs was mediated by CD4 or CD8 T cells but not by CD19 B cells. Furthermore, inhibitors of prostaglandin synthase or NOS restored the proliferation of T cells, whereas an inhibitor of indoleamine 2,3-dioxygenase and a transforming growth factor–β–neutralizing antibody had no effect. Finally, MSCs from inducible NOS−/− mice had a reduced ability to suppress T-cell proliferation. Taken together, these results suggest that NO produced by MSCs is one of the major mediators of T-cell suppression by MSCs.

scholarly journals Evidence of Immunosuppressive and Th2 Immune Polarizing Effects of Antidiabetic Momordica charantia Fruit Juice

2017 ◽  
Vol 2017 ◽  
pp. 1-13 ◽  
Author(s):  
Rufine Fachinan ◽  
Adnette Fagninou ◽  
Magloire Pandoua Nekoua ◽  
Abdou Madjid Amoussa ◽  
Marius Adjagba ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
T Cell ◽  
Fruit Juice ◽  
Momordica Charantia ◽  
T Cell Proliferation ◽  
T Helper ◽  
T Helper 1 ◽  
T Helper 2 ◽  
Human T Cell ◽  
Cell Proliferation And Differentiation

The mechanism of action of the antidiabetic capacity of Momordica charantia is still under investigation. Here, we assessed phytochemical compositions, antioxidant activity, and effects of total and filtered fruit and leafy stem juices of Momordica charantia on human T cell proliferation and differentiation through quantification of Th1/Th2 cytokines. In the absence of stimulation, total fruit and leafy stem juices induced significant T cell proliferation. Under PHA stimulation, both juices potentiated plant-induced T cell proliferation. However, the filtered fruit and leafy stem juices significantly inhibited PHA-stimulated T cell proliferation, while neither juice influenced T cell proliferation. Moreover, total and filtered fruit juice increased IL-4 secretion, while total and filtered leafy stem juice enhanced IFN-γ production. Phytochemical screening revealed the presence of tannins, flavonoids, anthocyans, steroids, and triterpenoids in both juices. Alkaloids, quinone derivatives, cardenolides, and cyanogenic derivatives were undetectable. The saponins present in total juices were undetectable after filtration. Moreover, both juices had appreciable antioxidant capacity. Our study supports the type 1 antidiabetic effect of filtered fruit juice of M. charantia which may be related to its immunosuppressive and T-helper 2 cell inducing capacities. Due to their immune-stimulatory activities and their ability to increase T-helper 1 cell cytokines, total fruit and leafy stem juices may serve in the treatment of immunodeficiency and certain infections.

scholarly journals CD26 Mediates Dissociation of Tollip and IRAK-1 from Caveolin-1 and Induces Upregulation of CD86 on Antigen-Presenting Cells

2005 ◽  
Vol 25 (17) ◽  
pp. 7743-7757 ◽  
Author(s):  
Kei Ohnuma ◽  
Tadanori Yamochi ◽  
Masahiko Uchiyama ◽  
Kunika Nishibashi ◽  
Satoshi Iwata ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
T Cell ◽  
Molecular Mechanisms ◽  
Interleukin 1 ◽  
Costimulatory Molecule ◽  
Antigen Presenting Cells ◽  
T Cell Proliferation ◽  
Caveolin 1 ◽  
Extracellular Region ◽  
Antigen Presenting

ABSTRACT CD26 is a T-cell costimulatory molecule with dipeptidyl peptidase IV enzyme activity in its extracellular region. We have previously reported that the addition of recombinant soluble CD26 resulted in enhanced proliferation of human T lymphocytes induced by the recall antigen tetanus toxoid (TT) via upregulation of CD86 on monocytes and that caveolin-1 was a binding protein of CD26, and the CD26-caveolin-1 interaction resulted in caveolin-1 phosphorylation (p-cav-1) as well as TT-mediated T-cell proliferation. However, the mechanism involved in this immune enhancement has not yet been elucidated. In the present work, we perform experiments to identify the molecular mechanisms by which p-cav-1 leads directly to the upregulation of CD86. Through proteomic analysis, we identify Tollip (Toll-interacting protein) and IRAK-1 (interleukin-1 receptor-associated serine/threonine kinase 1) as caveolin-1-interacting proteins in monocytes. We also demonstrate that following stimulation by exogenous CD26, Tollip and IRAK-1 dissociate from caveolin-1, and IRAK-1 is then phosphorylated in the cytosol, leading to the upregulation of CD86 via activation of NF-κB. Binding of CD26 to caveolin-1 therefore regulates signaling pathways in antigen-presenting cells to induce antigen-specific T-cell proliferation.

scholarly journals Allergen-Induced C5a/C5aR1 Axis Activation in Pulmonary CD11b+ cDCs Promotes Pulmonary Tolerance through Downregulation of CD40

Cells ◽  
2020 ◽  
Vol 9 (2) ◽  
pp. 300 ◽  
Author(s):  
Konstantina Antoniou ◽  
Fanny Ender ◽  
Tillman Vollbrandt ◽  
Yves Laumonnier ◽  
Franziska Rathmann ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
T Cells ◽  
T Cell ◽  
T Cell Activation ◽  
Cd4 T Cells ◽  
Cell Activation ◽  
T Cell Proliferation ◽  
C5a Receptor ◽  
The Impact

Activation of the C5/C5a/C5a receptor 1 (C5aR1) axis during allergen sensitization protects from maladaptive T cell activation. To explore the underlying regulatory mechanisms, we analyzed the impact of C5aR1 activation on pulmonary CD11b+ conventional dendritic cells (cDCs) in the context of house-dust-mite (HDM) exposure. BALB/c mice were intratracheally immunized with an HDM/ovalbumin (OVA) mixture. After 24 h, we detected two CD11b+ cDC populations that could be distinguished on the basis of C5aR1 expression. C5aR1− but not C5aR1+ cDCs strongly induced T cell proliferation of OVA-reactive transgenic CD4+ T cells after re-exposure to antigen in vitro. C5aR1− cDCs expressed higher levels of MHC-II and CD40 than their C5aR1+ counterparts, which correlated directly with a higher frequency of interactions with cognate CD4+ T cells. Priming of OVA-specific T cells by C5aR1+ cDCs could be markedly increased by in vitro blockade of C5aR1 and this was associated with increased CD40 expression. Simultaneous blockade of C5aR1 and CD40L on C5aR1+ cDCs decreased T cell proliferation. Finally, pulsing with OVA-induced C5 production and its cleavage into C5a by both populations of CD11b+ cDCs. Thus, we propose a model in which allergen-induced autocrine C5a generation and subsequent C5aR1 activation in pulmonary CD11b+ cDCs promotes tolerance towards aeroallergens through downregulation of CD40.

Ouabain induces inhibition of the progression phase in human T-cell proliferation

1995 ◽  
Vol 165 (2) ◽  
pp. 246-253 ◽  
Author(s):  
Chaya Brodie ◽  
Atilla Tordai ◽  
Joachim Saloga ◽  
Joanne Domenico ◽  
Erwin W. Gelfand
Keyword(s):  
Cell Proliferation ◽  
T Cell ◽  
T Cell Proliferation ◽  
Human T Cell

scholarly journals K12/SECTM1, an interferon-γ regulated molecule, synergizes with CD28 to costimulate human T cell proliferation

2011 ◽  
Vol 91 (3) ◽  
pp. 449-459 ◽  
Author(s):  
Tao Wang ◽  
Catherine Huang ◽  
Alfonso Lopez-Coral ◽  
Kimberly A. Slentz-Kesler ◽  
Min Xiao ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
T Cell ◽  
Interferon Γ ◽  
T Cell Proliferation ◽  
Human T Cell

scholarly journals Statin Modulation of Human T-Cell Proliferation, IL-1 and IL-17 Production, and IFN- T Cell Expression: Synergy with Conventional Immunosuppressive Agents

2013 ◽  
Vol 2013 ◽  
pp. 1-11 ◽  
Author(s):  
Ashmal Jameel ◽  
Kenneth G.-J. Ooi ◽  
Natasha R. Jeffs ◽  
Grazyna Galatowicz ◽  
Susan L. Lightman ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
T Cell ◽  
Immunosuppressive Agents ◽  
Experimental Models ◽  
T Cell Proliferation ◽  
Reductase Inhibitors ◽  
Human T Cell ◽  
Human Immune ◽  
Cell Expression

HMG-CoA reductase inhibitors (statins) have been demonstrated to be immunomodulatory for human immune-mediated disease and in experimental models. The aim of this study was to compare statin-mediated immunosuppressive effects on human T-cell responsesin vitrowith those of conventional immunosuppressives (dexamethasone, cyclosporin A (CsA), mycophenolate, and rapamycin). Statins (atorvastatin, lovastatin, and simvastatin) were investigated for their modulatory effects on human PBMC viability, cytokine profiles, and T-cell proliferation. At concentrations that inhibited anti-CD3/28-stimulated T-cell proliferation (), simvastatin significantly decreased intracellular CD4+T-cell expression of IFN- () to levels similar to those induced by conventional immunosuppressives. Atorvastatin and lovastatin also decreased IFN- expression, although to a lesser degree (). All three statins reduced levels of IL-17 production (). However, in response to anti-CD3/28 stimulation, simvastatin significantly upregulated IL-1 production (). The profile of cytokines produced in response to anti-CD3/28 stimulation was similar when both atorvastatin and dexamethasone were added as compared with dexamethasone alone, suggesting that atorvastatin can synergise with dexamethasone with respect to immunomodulation of cytokines. This data supports the hypothesis of selective statin-mediated immunomodulatory effects on human immune cells.

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