scholarly journals Role of selenium-containing proteins in T-cell and macrophage function

2010 ◽  
Vol 69 (3) ◽  
pp. 300-310 ◽  
Author(s):  
Bradley A. Carlson ◽  
Min-Hyuk Yoo ◽  
Rajeev K. Shrimali ◽  
Robert Irons ◽  
Vadim N. Gladyshev ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Immune Function ◽  
Inflammatory Responses ◽  
Inflammatory Diseases ◽  
Cell Receptor ◽  
Lymphoid Tissues ◽  
Protein Gel ◽  
Species Production

Selenium (Se) has been known for many years to have played a role in boosting the immune function, but the manner in which this element acts at the molecular level in host defence and inflammatory diseases is poorly understood. To elucidate the role of Se-containing proteins in the immune function, we knocked out the expression of this protein class in T-cells or macrophages of mice by targeting the removal of the selenocysteine tRNA gene using loxP-Cre technology. Mice with selenoprotein-less T-cells manifested reduced pools of mature and functional T-cells in lymphoid tissues and an impairment in T-cell-dependent antibody responses. Furthermore, selenoprotein deficiency in T-cells led to an inability of these cells to suppress reactive oxygen species production, which in turn affected their ability to proliferate in response to T-cell receptor stimulation. Selenoprotein-less macrophages, on the other hand, manifested mostly normal inflammatory responses, but this deficiency resulted in an altered regulation in extracellular matrix-related gene expression and a diminished migration of macrophages in a protein gel matrix. These observations provided novel insights into the role of selenoproteins in the immune function and tissue homeostasis.

scholarly journals Ceramide Synthase 2 Null Mice Are Protected from Ovalbumin-Induced Asthma with Higher T Cell Receptor Signal Strength in CD4+ T Cells

2021 ◽  
Vol 22 (5) ◽  
pp. 2713
Author(s):  
Sun-Hye Shin ◽  
Kyung-Ah Cho ◽  
Hee-Soo Yoon ◽  
So-Yeon Kim ◽  
Hee-Yeon Kim ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
T Cell Receptor ◽  
Cd4 T Cells ◽  
Acyl Chain ◽  
Signal Strength ◽  
Cell Receptor ◽  
Ceramide Synthase ◽  
Asthmatic Patients

(1) Background: six mammalian ceramide synthases (CerS1–6) determine the acyl chain length of sphingolipids (SLs). Although ceramide levels are increased in murine allergic asthma models and in asthmatic patients, the precise role of SLs with specific chain lengths is still unclear. The role of CerS2, which mainly synthesizes C22–C24 ceramides, was investigated in immune responses elicited by airway inflammation using CerS2 null mice. (2) Methods: asthma was induced in wild type (WT) and CerS2 null mice with ovalbumin (OVA), and inflammatory cytokines and CD4 (cluster of differentiation 4)+ T helper (Th) cell profiles were analyzed. We also compared the functional capacity of CD4+ T cells isolated from WT and CerS2 null mice. (3) Results: CerS2 null mice exhibited milder symptoms and lower Th2 responses than WT mice after OVA exposure. CerS2 null CD4+ T cells showed impaired Th2 and increased Th17 responses with concomitant higher T cell receptor (TCR) signal strength after TCR stimulation. Notably, increased Th17 responses of CerS2 null CD4+ T cells appeared only in TCR-mediated, but not in TCR-independent, treatment. (4) Conclusions: altered Th2/Th17 immune response with higher TCR signal strength was observed in CerS2 null CD4+ T cells upon TCR stimulation. CerS2 and very-long chain SLs may be therapeutic targets for Th2-related diseases such as asthma.

scholarly journals The major histocompatibility complex-restricted antigen receptor on T cells. II. Role of the L3T4 product.

1983 ◽  
Vol 158 (4) ◽  
pp. 1077-1091 ◽  
Author(s):  
P Marrack ◽  
R Endres ◽  
R Shimonkevitz ◽  
A Zlotnik ◽  
D Dialynas ◽  
...  
Keyword(s):  
T Cells ◽  
Major Histocompatibility Complex ◽  
T Cell ◽  
Cell Receptor ◽  
Surface Expression ◽  
High Avidity ◽  
Low Doses ◽  
Major Histocompatibility ◽  
Histocompatibility Complex

We have examined the role of the murine homologue of Leu-3 T4, L3T4, in recognition of antigen in association with products of the major histocompatibility complex (Ag/MHC) by murine T cell hybridomas. A series of ovalbumin (OVA)/I-Ad-specific T cell hybridomas were ranked in their sensitivity to Ag/I by measuring their ability to respond to low doses of OVA, or their sensitivity to inhibition by anti-I-Ad antibodies. T cell hybridomas with low apparent avidity for OVA/I-Ad, i.e. that did not respond well to low concentrations of OVA and were easily inhibited by anti-I-Ad, were also easily inhibited by anti-L3T4 antibodies. The reverse was true for T cell hybridomas with apparent high avidity for Ag/MHC. We found that the presence of low doses of anti-L3T4 antibodies caused T cell hybridomas to respond less well to low doses of Ag, and to be more easily inhibited by anti-I-Ad antibodies. These results suggested that the role of the L3T4 molecule is to increase the overall avidity of the reaction between T cells and Ag-presenting cells. In support of this idea was the discovery of several L3T4- subclones of one of our L3T4+ T cell hybridomas, D0.11.10. The L3T4- subclones had the same amount of receptor for OVA/I-Ad as their L3T4+ parent, as detected by an anti-receptor monoclonal antibody. The L3T4- subclones, however, responded less well to low doses of OVA, and were more easily inhibited by anti-I-Ad antibodies than their L3T4/ parent. These results showed that the L3T4 molecule was not required for surface expression of, or functional activity of, the T cell receptor for Ag/MHC. The L3T4 molecule did, however, increase the sensitivity with which the T cell reacted with Ag/MHC on Ag-presenting cells.

scholarly journals T Cell Receptor Specificity Is Critical for the Development of Epidermal γδ T Cells

2001 ◽  
Vol 194 (10) ◽  
pp. 1473-1483 ◽  
Author(s):  
Isabel Ferrero ◽  
Anne Wilson ◽  
Friedrich Beermann ◽  
Werner Held ◽  
H. Robson MacDonald
Keyword(s):  
T Cells ◽  
T Cell ◽  
T Cell Receptor ◽  
Cell Biology ◽  
Γδ T Cells ◽  
Cell Receptor ◽  
Wild Type ◽  
Normal Numbers ◽  
T Cell Biology

A particular feature of γδ T cell biology is that cells expressing T cell receptor (TCR) using specific Vγ/Vδ segments are localized in distinct epithelial sites, e.g., in mouse epidermis nearly all γδ T cells express Vγ3/Vδ1. These cells, referred to as dendritic epidermal T cells (DETC) originate from fetal Vγ3+ thymocytes. The role of γδ TCR specificity in DETC's migration/localization to the skin has remained controversial. To address this issue we have generated transgenic (Tg) mice expressing a TCR δ chain (Vδ6.3-Dδ1-Dδ2-Jδ1-Cδ), which can pair with Vγ3 in fetal thymocytes but is not normally expressed by DETC. In wild-type (wt) Vδ6.3Tg mice DETC were present and virtually all of them express Vδ6.3. However, DETC were absent in TCR-δ−/− Vδ6.3Tg mice, despite the fact that Vδ6.3Tg γδ T cells were present in normal numbers in other lymphoid and nonlymphoid tissues. In wt Vδ6.3Tg mice, a high proportion of in-frame Vδ1 transcripts were found in DETC, suggesting that the expression of an endogenous TCR-δ (most probably Vδ1) was required for the development of Vδ6.3+ epidermal γδ T cells. Collectively our data demonstrate that TCR specificity is essential for the development of γδ T cells in the epidermis. Moreover, they show that the TCR-δ locus is not allelically excluded.

scholarly journals Role of Exosomes in the Regulation of T-cell Mediated Immune Responses and in Autoimmune Disease

Cells ◽  
2019 ◽  
Vol 8 (2) ◽  
pp. 154 ◽  
Author(s):  
Alberto Anel ◽  
Ana Gallego-Lleyda ◽  
Diego de Miguel ◽  
Javier Naval ◽  
Luis Martínez-Lostao
Keyword(s):  
T Cells ◽  
T Cell ◽  
Autoimmune Disease ◽  
Immune Responses ◽  
T Regulatory Cells ◽  
Inflammatory Diseases ◽  
Activated T Cells ◽  
Regulatory Processes ◽  
Activation Induced Cell Death

: T-cell mediated immune responses should be regulated to avoid the development of autoimmune or chronic inflammatory diseases. Several mechanisms have been described to regulate this process, namely death of overactivated T cells by cytokine deprivation, suppression by T regulatory cells (Treg), induction of expression of immune checkpoint molecules such as CTLA-4 and PD-1, or activation-induced cell death (AICD). In addition, activated T cells release membrane microvesicles called exosomes during these regulatory processes. In this review, we revise the role of exosome secretion in the different pathways of immune regulation described to date and its importance in the prevention or development of autoimmune disease. The expression of membrane-bound death ligands on the surface of exosomes during AICD or the more recently described transfer of miRNA or even DNA inside T-cell exosomes is a molecular mechanism that will be analyzed.

Flexible migration program regulates γδ T-cell involvement in humoral immunity

Blood ◽  
2003 ◽  
Vol 102 (10) ◽  
pp. 3693-3701 ◽  
Author(s):  
Marlène Brandes ◽  
Katharina Willimann ◽  
Alois B. Lang ◽  
Ki-Hoan Nam ◽  
Chenggang Jin ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
B Cell ◽  
Humoral Immunity ◽  
Γδ T Cells ◽  
Cell Receptor ◽  
Lymphoid Tissues ◽  
Migration Program ◽  
And Function

Abstractγδ T cells are inadequately defined both in terms of their migration potential and contribution to antimicrobial immunity. Here, we have examined the migration profile of human blood γδ T cells and related cell lines and correlated these findings with their distribution in secondary lymphoid tissues and their function in B-cell cocultures. We find that resting γδ T cells are characterized by an inflammatory migration program similar to cells of the innate immune system. However, T-cell receptor (TCR) triggering resulted in the rapid but transient induction of a lymph node (LN)-homing program, as evidenced by functional CCR7 expression and concomitant reduction in expression and function of CCR5 and, to a lesser degree, CCR2. Moreover, the LN-homing program was reflected by the presence of γδ T cells in gastrointestinal lymphoid tissues, notably in clusters within germinal centers of B-cell follicles. In line with these findings, VγVδ-TCR triggering resulted in prominent expression of essential B-cell costimulatory molecules, including CD40L, OX40, CD70, and ICOS. Furthermore, γδ T cells were shown to provide potent B-cell help during in vitro antibody production. Collectively, our findings agree with a role for γδ T cells in humoral immunity during the early phase of antimicrobial responses. (Blood. 2003; 102:3693-3701)

scholarly journals The Role of the Thymus and Recent Thymic Migrants in the Maintenance of the Adult Peripheral Lymphocyte Pool

1998 ◽  
Vol 187 (11) ◽  
pp. 1839-1848 ◽  
Author(s):  
S.P. Berzins ◽  
R.L. Boyd ◽  
J.F.A.P. Miller
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cell Receptor ◽  
Export Ratio ◽  
Receptor Repertoire ◽  
Cell Pool ◽  
Peripheral T Cells ◽  
T Cell Receptor Repertoire ◽  
Cell Receptor Repertoire

The thymus is essential for the initial seeding of T cells to the periphery, but its role in maintaining the adult T cell pool remains poorly defined. We investigated whether changes to the rate of T cell export could form part of the mechanism(s) controlling the homeostatic regulation of the size and composition of the peripheral T cell pool. Using neonatal thymi grafted under the kidney capsule, we found that irrespective of whether the pool was oversupplied (by thymic grafts) or undersupplied (due to neonatal thymectomy), the thymic export rate was constant from both the host and graft thymus, and the periphery remained constant in size. Recent thymic emigrants (RTE) were also tracked to determine the extent of their acceptance into the T cell pool of a normal mouse. As a population, RTE are phenotypically mature, but were distinct from resident T cells in the periphery, being released in a CD4/CD8 ratio approximately twice that of established peripheral T cells. This export ratio is similar to that of T cells in the mature thymic compartment, but soon after entry into the periphery, the ratio falls, indicating separate thymic and peripheral regulation of the CD4/CD8 ratio. RTE may also be preferentially incorporated into the periphery, causing displacement of resident T cells, thus maintaining the size of the peripheral pool. Although not vital for the maintenance of a functional T cell pool, the acceptance of RTE in a “full” peripheral pool would ensure that the T cell receptor repertoire is kept diverse and that the T cell population encompasses a broad range of naive as well as memory T cells.

scholarly journals GITR-GITRL System, A Novel Player in Shock and Inflammation

2007 ◽  
Vol 7 ◽  
pp. 533-566 ◽  
Author(s):  
Ludovic Tibor Krausz ◽  
Rodolfo Bianchini ◽  
Simona Ronchetti ◽  
Katia Fettucciari ◽  
Giuseppe Nocentini ◽  
...  
Keyword(s):  
Innate Immunity ◽  
T Cells ◽  
Inflammatory Responses ◽  
Inflammatory Diseases ◽  
Tumor Necrosis Factor Receptor ◽  
Early Response ◽  
System A ◽  
Antigen Presenting

Glucocorticoid-induced TNFR-Related (GITR) protein is a member of the tumor necrosis factor receptor superfamily that modulates acquired and natural immune response. It is expressed in several cells and tissues, including T cells, natural killer cells, and, at lower levels, in cells of innate immunity. GITR is activated by its ligand, GITRL, mainly expressed on antigen presenting and endothelial cells. Recent evidence suggests that the GITR/GITRL system participates in the development of inflammatory responses, including shock, either due to early response of neutrophils and macrophages, or together with autoimmune/allergic pathogenesis. The pro-inflammatory role of the GITR/GITRL system is due to: 1) modulation of the extravasation process, 2) activation of innate immunity cells, 3) activation of effector T cells also favored by partial inhibition of suppressor T cells and modulation of dendritic function. This review summarizes thein vivorole of the GITR/GITRL system in inflammation and shock, explaining the mechanisms responsible for their effects, considering the interplay among the different cells of the immune system and transduction pathways activated by GITR and GITRL triggering. The hidden aspects about GITR/GITRL function, crucial for treatment planning of inflammatory diseases and shock by modulation of this system is stressed.

scholarly journals Ovalbumin antigen-specific activation of T cell receptor closely resembles soluble antibody stimulation as revealed by BOOST phosphotyrosine proteomics

2021 ◽  
Author(s):  
Xien Yu Chua ◽  
Arthur Salomon
Keyword(s):  
T Cells ◽  
T Cell ◽  
Tyrosine Phosphorylation ◽  
Cell Receptor ◽  
Binding Affinities ◽  
Spectrum Optimization ◽  
Wide Scale ◽  
Specific Antigens ◽  
Definition Of

Activation of T cell receptors (TCR) leads to a network of early signaling predominantly orchestrated by tyrosine phosphorylation in T cells. TCR are commonly activated using soluble anti-TCR antibodies, but this approach is not antigen-specific. Alternatively, activating the TCR using specific antigens of a range of binding affinities in the form of peptide-major histocompatibility complex (pMHC) is presumed to be more physiological. However, due to the lack of wide-scale phosphotyrosine (pTyr) proteomic studies directly comparing anti-TCR antibodies and pMHC, a comprehensive definition of these activated states remains enigmatic. Elucidation of the tyrosine phosphoproteome using quantitative pTyr proteomics enables a better understanding of the unique features of these activating agents and the role of ligand binding affinity on signaling. Here, we apply the recently established Broad-spectrum Optimization Of Selective Triggering (BOOST) to examine perturbations in tyrosine phosphorylation of TCR triggered by anti-TCR antibodies and pMHC. Our data reveals that high-affinity ovalbumin (OVA) pMHC activation of the TCR triggers a largely similar, albeit potentially stronger, pTyr-mediated signaling regulatory axis compared to anti-TCR antibody. Signaling output resulting from OVA pMHC variants correlates well with their weaker affinities, enabling affinity-tunable control of signaling strength. Collectively, we provide a framework for applying BOOST to compare pTyr-mediated signaling pathways of T cells activated in an antigen-independent and antigen-specific manner.

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