scholarly journals Upregulation of Phosphodiesterase 2A Augments T Cell Activation by Changing cGMP/cAMP Cross-Talk

2021 ◽  
Vol 12 ◽  
Author(s):  
Roberta Kurelic ◽  
Paula F. Krieg ◽  
Jana K. Sonner ◽  
Gloria Bhaiyan ◽  
Gustavo C. Ramos ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
T Cell Activation ◽  
Cross Talk ◽  
Cell Activation ◽  
Inflammatory Responses ◽  
T Cell Subsets ◽  
Activation Markers ◽  
Tcr Activation ◽  
Camp Levels

3′,5′-cyclic adenosine monophosphate (cAMP) is well-known for its diverse immunomodulatory properties, primarily inhibitory effects during T cell activation, proliferation, and production of pro-inflammatory cytokines. A decrease in cAMP levels, due to the hydrolyzing activity of phosphodiesterases (PDE), is favoring inflammatory responses. This can be prevented by selective PDE inhibitors, which makes PDEs important therapeutic targets for autoimmune disorders. In this study, we investigated the specific roles of PDE2A and PDE3B in the regulation of intracellular cAMP levels in different mouse T cell subsets. Unexpectedly, T cell receptor (TCR) activation led to a selective upregulation of PDE2A at the protein level in conventional T cells (Tcon), whereas no changes were detected in regulatory T cells (Treg). In contrast, protein expression of PDE3B was significantly higher in both non-activated and activated Tcon subsets as compared to Treg, with no changes upon TCR engagement. Live-cell imaging of T cells expressing a highly sensitive Förster resonance energy transfer (FRET)-based biosensor, Epac1-camps, has enabled cAMP measurements in real time and revealed stronger responses to the PDE2A inhibitors in activated vs non-activated Tcon. Importantly, stimulation of intracellular cGMP levels with natriuretic peptides led to an increase of cAMP in non-activated and a decrease of cAMP in activated Tcon, suggesting that TCR activation changes the PDE3B-dependent positive to PDE2A-dependent negative cGMP/cAMP cross-talk. Functionally, this switch induced higher expression of early activation markers CD25 and CD69. This constitutes a potentially interesting feed-forward mechanism during autoimmune and inflammatory responses that may be exploited therapeutically.

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.

scholarly journals CD4+ T-Cell Subsets That Mediate Immunological Memory to Mycobacterium tuberculosis Infection in Mice

2000 ◽  
Vol 68 (2) ◽  
pp. 621-629 ◽  
Author(s):  
Peter Andersen ◽  
Birgitte Smedegaard
Keyword(s):  
T Cells ◽  
Mycobacterium Tuberculosis ◽  
T Cell ◽  
T Cell Activation ◽  
Cell Activation ◽  
Immunological Memory ◽  
T Cell Subsets ◽  
Small Subset ◽  
Memory Cells ◽  
Activation Markers

ABSTRACT We have studied CD4+ T cells that mediate immunological memory to an intravenous infection with Mycobacterium tuberculosis. The studies were conducted with a mouse model of memory immunity in which mice are rendered immune by a primary infection followed by antibiotic treatment and rest. Shortly after reinfection, tuberculosis-specific memory cells were recruited from the recirculating pool, leading to rapidly increasing precursor frequencies in the liver and a simultaneous decrease in the blood. A small subset of the infiltrating T cells was rapidly activated (<20 h) and expressed high levels of intracellular gamma interferon and the T-cell activation markers CD69 and CD25. These memory effector T cells expressed intermediate levels of CD45RB and were heterogeneous with regard to the L-selectin and CD44 markers. By adoptive transfer into nude mice, the highest level of resistance to a challenge with M. tuberculosis was mediated by CD45RBhigh,l-selectinhigh, CD44low cells. Taken together, these two lines of evidence support an important role for memory cells which have reverted to a naive phenotype in the long-term protection against M. tuberculosis.

CVID patients with autoimmunity have elevated T cell expression of granzyme B and HLA-DR and reduced levels of Treg cells

2012 ◽  
Vol 66 (2) ◽  
pp. 146-150 ◽  
Author(s):  
Clive R D Carter ◽  
Ganesha Aravind ◽  
Natuley L Smalle ◽  
June Y Cole ◽  
Sinisa Savic ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
T Cell Activation ◽  
Cell Activation ◽  
Granzyme B ◽  
Treg Cells ◽  
T Cell Subsets ◽  
Activated T Cells ◽  
Activation Markers ◽  
Hla Dr

AimsCommon variable immunodeficiency (CVID) is a primary antibody immunodeficiency with approximately 20% of patients reporting additional autoimmune symptoms. The primary aim of this study was to compare the levels of activated and regulatory T cells (Treg cells) in CVID patients in an attempt to clarify their possible interactions leading to the generation of autoimmunity.MethodsImmunophenotyping of T cells was performed by flow cytometry using a whole blood approach. Surface expression of human leukocyte antigen HLA class II DR and intracellular levels of granzyme B in T cell subsets were assessed; Treg levels were measured using CD4 CD25, FOXp3 and CTLA-4.ResultsCVID patients had higher levels of granzyme B and HLA-DR on CD8+ T cells compared with control values (mean of 59% vs 30% and 45% vs 21%, respectively). Patients also had reduced levels of Treg cells compared with control values (con mean=3.24% vs pat=2.54%). Patients with autoimmunity (5/23) had a similar level of T cell activation markers to the rest of the patients but with lower Treg cells (mean of 1.1%) and reduced CD25 and CTLA-4 expression. Patients with autoimmunity had a higher ratio of activated to Treg cells compared with patients with no autoimmune symptoms.ConclusionsThese results highlight that reduced levels of Treg cells were associated with elevated levels of activated T cells, suggesting that reduced Treg cells in these patients may have functional consequences in allowing exaggerated T cell responses.

scholarly journals The GSK3β-β-catenin-TCF1 pathway improves naive T cell activation in old adults by upregulating miR-181a

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Zhongde Ye ◽  
Timothy M. Gould ◽  
Huimin Zhang ◽  
Jun Jin ◽  
Cornelia M. Weyand ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
T Cell Activation ◽  
Cell Activation ◽  
The Elderly ◽  
Cell Receptor ◽  
Tcr Signaling ◽  
Activation Markers ◽  
Old Adults ◽  
Tcr Activation

AbstractMicroRNAs play an important role in the regulation of T cell development, activation, and differentiation. One of the most abundant microRNAs in lymphocytes is miR-181a, which controls T cell receptor (TCR) activation thresholds in thymic selection as well as in peripheral T cell responses. We previously found that miR-181a levels decline in T cells in the elderly. In this study, we identified TCF1 as a transcriptional regulator of pri-miR-181a. A decline in TCF1 levels in old individuals accounted for the reduced miR-181a expression impairing TCR signaling. Inhibition of GSK3ß restored expression of miR-181a by inducing TCF1 in T cells from old adults. GSK3ß inhibition enhanced TCR signaling to increase downstream expression of activation markers and production of IL-2. The effect involved the upregulation of miR-181a and the inhibition of DUSP6 expression. Thus, inhibition of GSK3ß can restore responses of old T cells by inducing miR-181a expression through TCF1.

scholarly journals CCL21 mediates CD4+ T-cell costimulation via a DOCK2/Rac-dependent pathway

Blood ◽  
2009 ◽  
Vol 114 (3) ◽  
pp. 580-588 ◽  
Author(s):  
Kathrin Gollmer ◽  
François Asperti-Boursin ◽  
Yoshihiko Tanaka ◽  
Klaus Okkenhaug ◽  
Bart Vanhaesebroeck ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
T Cell Activation ◽  
Cd4 T Cells ◽  
Cell Activation ◽  
Early Time ◽  
Cell Receptor ◽  
Tcr Signaling ◽  
Activation Markers

Abstract CD4+ T cells use the chemokine receptor CCR7 to home to and migrate within lymphoid tissue, where T-cell activation takes place. Using primary T-cell receptor (TCR)–transgenic (tg) CD4+ T cells, we explored the effect of CCR7 ligands, in particular CCL21, on T-cell activation. We found that the presence of CCL21 during early time points strongly increased in vitro T-cell proliferation after TCR stimulation, correlating with increased expression of early activation markers. CCL21 costimulation resulted in increased Ras- and Rac-GTP formation and enhanced phosphorylation of Akt, MEK, and ERK but not p38 or JNK. Kinase-dead PI3KδD910A/D910A or PI3Kγ-deficient TCR-tg CD4+ T cells showed similar responsiveness to CCL21 costimulation as control CD4+ T cells. Conversely, deficiency in the Rac guanine exchange factor DOCK2 significantly impaired CCL21-mediated costimulation in TCR-tg CD4+ T cells, concomitant with impaired Rac- but not Ras-GTP formation. Using lymph node slices for live monitoring of T-cell behavior and activation, we found that G protein-coupled receptor signaling was required for early CD69 expression but not for Ca2+ signaling. Our data suggest that the presence of CCL21 during early TCR signaling lowers the activation threshold through Ras- and Rac-dependent pathways leading to increased ERK phosphorylation.

scholarly journals TRPM2 Is Not Required for T-Cell Activation and Differentiation

2022 ◽  
Vol 12 ◽  
Author(s):  
Niels C. Lory ◽  
Mikolaj Nawrocki ◽  
Martina Corazza ◽  
Joanna Schmid ◽  
Valéa Schumacher ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
T Cell Activation ◽  
Cell Activation ◽  
Transient Receptor Potential ◽  
Cell Function ◽  
Intestinal Inflammation ◽  
Activation Markers

Antigen recognition by the T-cell receptor induces a cytosolic Ca2+ signal that is crucial for T-cell function. The Ca2+ channel TRPM2 (transient receptor potential cation channel subfamily M member 2) has been shown to facilitate influx of extracellular Ca2+ through the plasma membrane of T cells. Therefore, it was suggested that TRPM2 is involved in T-cell activation and differentiation. However, these results are largely derived from in vitro studies using T-cell lines and non-physiologic means of TRPM2 activation. Thus, the relevance of TRPM2-mediated Ca2+ signaling in T cells remains unclear. Here, we use TRPM2-deficient mice to investigate the function of TRPM2 in T-cell activation and differentiation. In response to TCR stimulation in vitro, Trpm2-/- and WT CD4+ and CD8+ T cells similarly upregulated the early activation markers NUR77, IRF4, and CD69. We also observed regular proliferation of Trpm2-/- CD8+ T cells and unimpaired differentiation of CD4+ T cells into Th1, Th17, and Treg cells under specific polarizing conditions. In vivo, Trpm2-/- and WT CD8+ T cells showed equal specific responses to Listeria monocytogenes after infection of WT and Trpm2-/- mice and after transfer of WT and Trpm2-/- CD8+ T cells into infected recipients. CD4+ T-cell responses were investigated in the model of anti-CD3 mAb-induced intestinal inflammation, which allows analysis of Th1, Th17, Treg, and Tr1-cell differentiation. Here again, we detected similar responses of WT and Trpm2-/- CD4+ T cells. In conclusion, our results argue against a major function of TRPM2 in T-cell activation and differentiation.

EP.WE.805From bench to bedside; A rationale for Immunotherapy in the adjuvant setting for Oesophageal cancer

2021 ◽  
Vol 108 (Supplement_7) ◽  
Author(s):  
Noel Donlon ◽  
Maria Davern ◽  
Andrew Sheppard ◽  
John Reynolds ◽  
Joanne Lysaght
Keyword(s):  
T Cells ◽  
T Cell ◽  
T Cell Activation ◽  
Immune Checkpoint ◽  
Cell Activation ◽  
Single Agent ◽  
T Cell Subsets ◽  
Effector Memory ◽  
Post Surgery ◽  
Post Operative Period

Abstract Background Immunotherapy is being intensively investigated for its utilisation in the curative setting as a single agent and in the multimodal setting, however, the most appropriate time to incorporate ICIs remains unknown. Our study profiles systemic anti-tumour immunity perioperatively to provide a rationale for adjuvant immunotherapy. Methods Systemic immunity was immunophenotyped pre and post-oesophagectomy on days 0, 1, 3, 7 and week 6 by flow cytometry (n = 14). The frequency of circulating lymphocytes, T cells, cytotoxic and helper T lymphocytes was profiled longitudinally including the proportion of T cell subsets in circulation. This study also profiled immune checkpoint expression on circulating T cells including: PD-1, CTLA-4, TIGIT, TIM-3, LAG-3, PD-L1 and PD-L2. Markers of immunogenicity (calreticulin, HMGB1 and MIC-A/B) were also assessed. Results The frequency of circulating CD27 + T cells increases sequentially in the immediate post-operative period peaking on day 7 in OAC patients. (p &lt; 0.01) There is a sequential decrease in the percentage of effector memory and central memory T cells in circulation and an increase in the percentage of naïve T cells in peripheral circulation of OAC patients in the immediate post-operative period. The expression of CTLA-4 on the surface of circulating CD4 + T cells decreases 6 weeks post-operatively in OAC patients. Conclusions We observed increased T cell activation and immune checkpoints immediately post-surgery with returns to baseline by week 6. These results suggest that immune checkpoint inhibitors such as anti-PD-1 may be beneficial immediately post-surgery to maintain T cell activation and prevent exhaustion of this increased population of activated T cells observed immediately post-surgery.

scholarly journals Rapid Flow Cytometry Method for Quantitation of LFA-1-Adhesive T Cells

2006 ◽  
Vol 13 (3) ◽  
pp. 403-408 ◽  
Author(s):  
Brian Crucian ◽  
Mayra Nelman-Gonzalez ◽  
Clarence Sams
Keyword(s):  
Flow Cytometry ◽  
T Cells ◽  
T Cell ◽  
T Cell Activation ◽  
Cell Activation ◽  
T Cell Subsets ◽  
Activated T Cells ◽  
Peripheral Blood Mononuclear ◽  
Simple Method ◽  
Rapid Flow

ABSTRACT Adhesion molecules are important for leukocyte endothelial attachment and migration to sites of inflammation. The LFA-1 (CD11a and CD18) integrin molecule is constitutively expressed on the T-cell surface. Following T-cell activation, a rapid conformational change of LFA-1 to an “adhesive” state occurs, allowing LFA-1 binding to intracellular cell adhesion molecule type 1 (ICAM-1)-expressing targets, such as antigen-presenting cells. For this study, a rapid flow cytometry method for the quantitation of LFA-1-adhesive T cells following activation was developed. Purified ICAM-1 was bound to 4.5-μm-diameter beads. Following peripheral blood mononuclear cell activation culture (phorbol myristate acetate and ionomycin), the cells were incubated with the ICAM-1 beads, which allowed attachment to occur. The T cell-bead complexes were then resolved from unbound T cells by flow cytometry. Multicolor analysis allowed a complete phenotypic analysis of the adhesive T-cell subsets. Experimental controls indicated that the T cell-bead attachment was LFA-1 and ICAM-1 specific. Very little binding between unactivated T cells and ICAM beads or between activated T cells and plain beads was observed. The kinetics of the response was extremely rapid, with nearly maximal numbers of adhesive T cells observed following 5 min of activation. Scanning electron microscopy analysis was used to characterize legitimate bead-cell binding. By using multicolor cytometry, the responding adhesive T-cell population was usually identified as a distinct subset of T cells with the following phenotype: CD3+ CD4+ or CD8+ CD19− CD16− CD45RO+ CD62L+ CD27+ CD57−. A rapid and simple method for the scoring of LFA-1-adhesive T cells was developed and may have significant utility for immune function studies.

scholarly journals Early Immune Markers Associated withMycobacterium aviumsubsp.paratuberculosisInfection in a Neonatal Calf Model

2011 ◽  
Vol 18 (3) ◽  
pp. 393-405 ◽  
Author(s):  
J. R. Stabel ◽  
S. Robbe-Austerman
Keyword(s):  
T Cell ◽  
T Cell Activation ◽  
Lymphocyte Proliferation ◽  
Cell Activation ◽  
The Other ◽  
T Cell Subsets ◽  
Cell Mediated Immunity ◽  
Activation Markers ◽  
Oral Inoculation ◽  
Ifn Γ

ABSTRACTThe objective of this study was to observe early markers of cell-mediated immunity in naïve calves infected withMycobacterium aviumsubsp.paratuberculosisand how expression of these markers evolved over the 12-month period of infection. Groups for experimental infection included control (noninfected), oral (infected orally withM. aviumsubsp.paratuberculosisstrain K-10), oral/DXM (pretreatment with dexamethasone before oral inoculation), intraperitoneal (i.p.) inoculation, and oral/M (oral inoculation with mucosal scrapings from a cow with clinical disease) groups. One of the earliest markers to emerge was antigen-specific gamma interferon (IFN-γ). Only i.p. inoculated calves had detectable antigen-specific IFN-γ responses at 7 days, with responses of the other infection groups becoming detectable at 90 and 120 days. All infection groups maintained robust IFN-γ responses for the remainder of the study. At 1 month, calves in the oral and oral/M groups had higher antigen-stimulated interleukin-10 (IL-10) levels than calves in the other treatment groups, but IL-10 secretion declined by 12 months for all calves. T-cell activation markers such as CD25, CD26, CD45RO, and CD5 were significantly upregulated in infected calves compared to noninfected controls. Oral inoculation of calves resulted in significantly increased antigen-specific lymphocyte proliferation at 9 and 12 months, as well as inducible nitric oxide synthase (iNOS) secretion at 6 and 12 months. These results demonstrate that infection of naïve calves withM. aviumsubsp.paratuberculosisinvoked early immunologic responses characterized by robust antigen-specific IFN-γ responses and induction of CD25 and CD45RO expression on T-cell subsets. These were followed by antigen-specific lymphocyte proliferation, iNOS secretion, and expression of CD26 and CD5brightmarkers in the latter part of the 12-month study.

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