scholarly journals Distinct cellular immune profiles in the airways and blood of critically ill patients with COVID-19

2020 ◽  
Author(s):  
Anno Saris ◽  
Tom D.Y. Reijnders ◽  
Esther J. Nossent ◽  
Alex R. Schuurman ◽  
Jan Verhoeff ◽  
...  
Keyword(s):  
Immune Response ◽  
T Cells ◽  
T Cell ◽  
T Cell Activation ◽  
Peripheral Blood ◽  
Cell Activation ◽  
Effector Memory ◽  
Activated T Cells ◽  
Immune Profile ◽  
Prolonged Icu Stay

AbstractOur understanding of the coronavirus disease-19 (COVID-19) immune response is almost exclusively derived from studies that examined blood. To gain insight in the pulmonary immune response we analysed BALF samples and paired blood samples from 17 severe COVID-19 patients. Macrophages and T cells were the most abundant cells in BALF. In the lungs, both CD4 and CD8 T cells were predominantly effector memory cells and expressed higher levels of the exhaustion marker PD-1 than in peripheral blood. Prolonged ICU stay associated with a reduced proportion of activated T cells in peripheral blood and even more so in BALF. T cell activation in blood, but not in BALF, was higher in fatal COVID-19 cases. Increased levels of inflammatory mediators were more pronounced in BALF than in plasma. In conclusion, the bronchoalveolar immune response in COVID-19 has a unique local profile that strongly differs from the immune profile in peripheral blood.SummaryThe bronchoalveolar immune response in severe COVID-19 strongly differs from the peripheral blood immune profile. Fatal COVID-19 associated with T cell activation blood, but not in BALF.

scholarly journals Distinct cellular immune profiles in the airways and blood of critically ill patients with COVID-19

Thorax ◽  
2021 ◽  
pp. thoraxjnl-2020-216256
Author(s):  
Anno Saris ◽  
Tom DY Reijnders ◽  
Esther J Nossent ◽  
Alex R Schuurman ◽  
Jan Verhoeff ◽  
...  
Keyword(s):  
Immune Response ◽  
T Cells ◽  
T Cell ◽  
T Cell Activation ◽  
Inflammatory Mediators ◽  
Peripheral Blood ◽  
Cell Activation ◽  
Mononuclear Cells ◽  
Effector Memory ◽  
Activated T Cells

BackgroundKnowledge of the pathophysiology of COVID-19 is almost exclusively derived from studies that examined the immune response in blood. We here aimed to analyse the pulmonary immune response during severe COVID-19 and to compare this with blood responses.MethodsThis was an observational study in patients with COVID-19 admitted to the intensive care unit (ICU). Mononuclear cells were purified from bronchoalveolar lavage fluid (BALF) and blood, and analysed by spectral flow cytometry; inflammatory mediators were measured in BALF and plasma.FindingsPaired blood and BALF samples were obtained from 17 patients, four of whom died in the ICU. Macrophages and T cells were the most abundant cells in BALF, with a high percentage of T cells expressing the ƴδ T cell receptor. In the lungs, both CD4 and CD8 T cells were predominantly effector memory cells (87·3% and 83·8%, respectively), and these cells expressed higher levels of the exhaustion marker programmad death-1 than in peripheral blood. Prolonged ICU stay (>14 days) was associated with a reduced proportion of activated T cells in peripheral blood and even more so in BALF. T cell activation in blood, but not in BALF, was higher in fatal COVID-19 cases. Increased levels of inflammatory mediators were more pronounced in BALF than in plasma.InterpretationThe bronchoalveolar immune response in COVID-19 has a unique local profile that strongly differs from the immune profile in peripheral blood. Fully elucidating COVID-19 pathophysiology will require investigation of the pulmonary immune response.

scholarly journals Functional expression of B7/BB1 on activated T lymphocytes.

1993 ◽  
Vol 177 (3) ◽  
pp. 845-850 ◽  
Author(s):  
M Azuma ◽  
H Yssel ◽  
J H Phillips ◽  
H Spits ◽  
L L Lanier
Keyword(s):  
T Cells ◽  
T Cell ◽  
T Cell Activation ◽  
Peripheral Blood ◽  
Cell Activation ◽  
Cd8 T Cell ◽  
Cd4 T Cell ◽  
Activated T Cells ◽  
T Cell Clones ◽  
Cell Clones

B7/BB1 is a membrane differentiation antigen expressed on activated B cells, macrophages, and dendritic cells that binds to a counter-receptor, CD28, expressed on T lymphocytes and thymocytes. Interaction between CD28 and B7 results in potent costimulation of T cell activation initiated via the CD3/T cell receptor complex. We now report that B7 is also expressed on activated human peripheral blood T cells, CD4 T cell clones, CD8 T cell clones, and natural killer cell clones. B7 appears relatively late after T cell activation, can be detected on both CD4 and CD8 T cell subsets, and is present on antigen-specific, major histocompatibility complex-restricted CD4 and CD8 T cell clones. Expression of B7 on activated T cells was confirmed by immunoprecipitation from 125I-labeled activated T cells and by detection of B7 transcripts. A B7+ CD4+ T cell clone was able to stimulate a primary allogeneic mixed lymphocyte response using small, resting peripheral blood T cells as responders. The alloantigen-induced proliferative response and cytokine production was partially inhibited by anti-B7 monoclonal antibody. Since activated T cells can coexpress both CD28 and its counter-receptor, B7, this suggests that activated T cells may be capable of autocrine costimulation via the CD28 activation pathway.

CD28: A New Drug Target for Immune Disease

2020 ◽  
Vol 21 (6) ◽  
pp. 589-598
Author(s):  
Sijing Xia ◽  
Qin Chen ◽  
Bing Niu
Keyword(s):  
Immune Response ◽  
T Cells ◽  
T Cell ◽  
T Cell Activation ◽  
Cell Activation ◽  
Relevant Literature ◽  
Surface Glycoprotein ◽  
Special Role ◽  
Activated T Cells ◽  
Cell Surface Glycoprotein

Background: CD28, a cell surface glycoprotein receptor, predominantly expressed on activated T cells, belongs to the Ig superfamily and provides a critical co-stimulatory signal. CTLA-4 has sequence homology to CD28, and is expressed on T cells after activation. It provides an inhibition signal coordinated with CD28 to regulate T cell activation. Both of them regulate T cell proliferation and differentiation and play an important role in the immune response pathway in vivo. Objective: We studied the special role of different structural sites of CD28 in producing costimulatory signals. Methods: We reviewed the relevant literature, mainly regarding the structure of CD28 to clarify its biological function, and its role in the immune response. Results: In recent years, increasingly attention has been paid to CD28, which is considered as a key therapeutic target for many modern diseases, especially some immune diseases. Conclusion: In this paper, we mainly introduce the structure of CD28 and its related biological functions, as well as the application of costimulatory pathways targeting CD28 in disease treatment.

scholarly journals TCR Recognition of Peptide–MHC-I: Rule Makers and Breakers

2020 ◽  
Vol 22 (1) ◽  
pp. 68
Author(s):  
Christopher Szeto ◽  
Christian A. Lobos ◽  
Andrea T. Nguyen ◽  
Stephanie Gras
Keyword(s):  
Immune Response ◽  
T Cells ◽  
T Cell ◽  
T Cell Activation ◽  
Cell Activation ◽  
Adaptive Immune System ◽  
Human Leukocyte ◽  
Activated T Cells ◽  
Mhc I ◽  
Mhc Molecules

T cells are a critical part of the adaptive immune system that are able to distinguish between healthy and unhealthy cells. Upon recognition of protein fragments (peptides), activated T cells will contribute to the immune response and help clear infection. The major histocompatibility complex (MHC) molecules, or human leukocyte antigens (HLA) in humans, bind these peptides to present them to T cells that recognise them with their surface T cell receptors (TCR). This recognition event is the first step that leads to T cell activation, and in turn can dictate disease outcomes. The visualisation of TCR interaction with pMHC using structural biology has been crucial in understanding this key event, unravelling the parameters that drive this interaction and their impact on the immune response. The last five years has been the most productive within the field, wherein half of current unique TCR–pMHC-I structures to date were determined within this time. Here, we review the new insights learned from these recent TCR–pMHC-I structures and their impact on T cell activation.

scholarly journals Novel self-amplificatory loop between T cells and tenocytes as a driver of chronicity in tendon disease

2021 ◽  
pp. annrheumdis-2020-219335
Author(s):  
Emma Garcia-Melchor ◽  
Giacomo Cafaro ◽  
Lucy MacDonald ◽  
Lindsay A N Crowe ◽  
Shatakshi Sood ◽  
...  
Keyword(s):  
T Cells ◽  
Cell Migration ◽  
T Cell ◽  
Inflammatory Cytokines ◽  
T Cell Activation ◽  
Cell Activation ◽  
Conditioned Media ◽  
Tissue Remodelling ◽  
Activated T Cells ◽  
T Cell Migration

ObjectivesIncreasing evidence suggests that inflammatory mechanisms play a key role in chronic tendon disease. After observing T cell signatures in human tendinopathy, we explored the interaction between T cells and tendon stromal cells or tenocytes to define their functional contribution to tissue remodelling and inflammation amplification and hence disease perpetuation.MethodsT cells were quantified and characterised in healthy and tendinopathic tissues by flow cytometry (FACS), imaging mass cytometry (IMC) and single cell RNA-seq. Tenocyte activation induced by conditioned media from primary damaged tendon or interleukin-1β was evaluated by qPCR. The role of tenocytes in regulating T cell migration was interrogated in a standard transwell membrane system. T cell activation (cell surface markers by FACS and cytokine release by ELISA) and changes in gene expression in tenocytes (qPCR) were assessed in cocultures of T cells and explanted tenocytes.ResultsSignificant quantitative differences were observed in healthy compared with tendinopathic tissues. IMC showed T cells in close proximity to tenocytes, suggesting tenocyte–T cell interactions. On activation, tenocytes upregulated inflammatory cytokines, chemokines and adhesion molecules implicated in T cell recruitment and activation. Conditioned media from activated tenocytes induced T cell migration and coculture of tenocytes with T cells resulted in reciprocal activation of T cells. In turn, these activated T cells upregulated production of inflammatory mediators in tenocytes, while increasing the pathogenic collagen 3/collagen 1 ratio.ConclusionsInteraction between T cells and tenocytes induces the expression of inflammatory cytokines/chemokines in tenocytes, alters collagen composition favouring collagen 3 and self-amplifies T cell activation via an auto-regulatory feedback loop. Selectively targeting this adaptive/stromal interface may provide novel translational strategies in the management of human tendon disorders.

NFATc3 regulates the transcription of genes involved in T-cell activation and angiogenesis

Blood ◽  
2011 ◽  
Vol 118 (3) ◽  
pp. 795-803 ◽  
Author(s):  
Katia Urso ◽  
Arantzazu Alfranca ◽  
Sara Martínez-Martínez ◽  
Amelia Escolano ◽  
Inmaculada Ortega ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
T Cell Activation ◽  
Cell Activation ◽  
Target Genes ◽  
Gene Knockout ◽  
Activated T Cells ◽  
Knock Down ◽  
And Function

Abstract The nuclear factor of activated T cells (NFAT) family of transcription factors plays important roles in many biologic processes, including the development and function of the immune and vascular systems. Cells usually express more than one NFAT member, raising the question of whether NFATs play overlapping roles or if each member has selective functions. Using mRNA knock-down, we show that NFATc3 is specifically required for IL2 and cyclooxygenase-2 (COX2) gene expression in transformed and primary T cells and for T-cell proliferation. We also show that NFATc3 regulates COX2 in endothelial cells, where it is required for COX2, dependent migration and angiogenesis in vivo. These results indicate that individual NFAT members mediate specific functions through the differential regulation of the transcription of target genes. These effects, observed on short-term suppression by mRNA knock-down, are likely to have been masked by compensatory effects in gene-knockout studies.

Parasite species regulates T cell activation in human malaria

2021 ◽  
Author(s):  
Florian Bach ◽  
Diana Munoz Sandoval ◽  
Michalina Mazurczyk ◽  
Yrene Themistocleous ◽  
Thomas A Rawlinson ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Plasmodium Vivax ◽  
T Cell Activation ◽  
Cell Activation ◽  
Parasite Species ◽  
Field Isolate ◽  
Effector Memory ◽  
Lymphoid Tissues ◽  
Systems Immunology

Plasmodium vivax offers unique challenges for malaria control and may prove a more difficult species to eradicate than Plasmodium falciparum. Yet compared to P. falciparum we know very little about the innate and adaptive immune responses that need to be harnessed to reduce disease and transmission. In this study, we inoculated human volunteers with a clonal field isolate of P. vivax and used systems immunology tools to track their response through infection and convalescence. Our data reveal Plasmodium vivax triggers an acute phase response that shares remarkable overlap with that of P. falciparum, suggesting a hardwired innate response that does not differentiate between parasite species. This leads to the global recruitment of innate-like and adaptive T cells into lymphoid tissues where up to one quarter of the T cell compartment is activated. Heterogeneous effector memory-like CD4+ T cells dominate this response and their activation coincides with collateral tissue damage. Remarkably, comparative transcriptional analyses show that P. falciparum drives even higher levels of T cell activation; diverging T cell responses may therefore explain why falciparum malaria more frequently causes severe disease.

T cells: a dedicated effector kinase pathways for every trait?

2021 ◽  
Vol 478 (6) ◽  
pp. 1303-1307
Author(s):  
Kriti Bahl ◽  
Jeroen P. Roose
Keyword(s):  
T Cells ◽  
T Cell ◽  
T Cell Activation ◽  
Cell Activation ◽  
Cell Receptor ◽  
Spectrometric Analysis ◽  
Activated T Cells ◽  
Biological Responses ◽  
Extracellular Signal ◽  
Differentiation And Proliferation

Signaling pathways play critical roles in regulating the activation of T cells. Recognition of foreign peptide presented by MHC to the T cell receptor (TCR) triggers a signaling cascade of proximal kinases and adapter molecules that lead to the activation of Effector kinase pathways. These effector kinase pathways play pivotal roles in T cell activation, differentiation, and proliferation. RNA sequencing-based methods have provided insights into the gene expression programs that support the above-mentioned cell biological responses. The proteome is often overlooked. A recent study by Damasio et al. [Biochem. J. (2021) 478, 79–98. doi:10.1042/BCJ20200661] focuses on characterizing the effect of extracellular signal-regulated kinase (ERK) on the remodeling of the proteome of activated CD8+ T cells using Mass spectrometric analysis. Surprisingly, the Effector kinase ERK pathway is responsible for only a select proportion of the proteome that restructures during T cell activation. The primary targets of ERK signaling are transcription factors, cytokines, and cytokine receptors. In this commentary, we discuss the recent findings by Damasio et al. [Biochem. J. (2021) 478, 79–98. doi:10.1042/BCJ20200661] in the context of different Effector kinase pathways in activated T cells.

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.

scholarly journals Extracellular signal-regulated kinase (ERK) pathway control of CD8+ T cell differentiation

2020 ◽  
Author(s):  
Marcos P. Damasio ◽  
Julia M. Marchingo ◽  
Laura Spinelli ◽  
Doreen A. Cantrell ◽  
Andrew J.M. Howden
Keyword(s):  
T Cells ◽  
T Cell ◽  
T Cell Activation ◽  
Cell Activation ◽  
Antigen Receptor ◽  
T Cell Differentiation ◽  
Signalling Pathways ◽  
Activated T Cells ◽  
Transcriptional Reprogramming ◽  
Extracellular Signal

SummaryThe integration of multiple signalling pathways that co-ordinate T cell metabolism and transcriptional reprogramming is required to drive T cell differentiation and proliferation. One key T cell signalling module is mediated by extracellular signal-regulated kinases (ERKs) which are activated in response to antigen receptor engagement. The activity of ERKs is often used to report antigen receptor occupancy but the full details of how ERKs control T cell activation is not understood. Accordingly, we have used mass spectrometry to explore how ERK signalling pathways control antigen receptor driven proteome restructuring in CD8 + T cells to gain insights about the biological processes controlled by ERKs in primary lymphocytes. Quantitative analysis of >8000 proteins identified only 900 ERK regulated proteins in activated CD8+ T cells. The data identify both positive and negative regulatory roles for ERKs during T cell activation and reveal that ERK signalling primarily controls the repertoire of transcription factors, cytokines and cytokine receptors expressed by activated T cells. The ERKs thus drive the transcriptional reprogramming of activated T cells and the ability of T cells to communicate with external immune cues.

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