scholarly journals The role of synovial T-cell infiltration following knee joint injury in symptoms and progression to osteoarthritis

2019 ◽  
Author(s):  
Babak Moradi ◽  
Miriam T Jackson ◽  
Cindy C. Shu ◽  
Susan M Smith ◽  
Margaret M Smith ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Immune Cell ◽  
Post Injury ◽  
Joint Injury ◽  
Cell Responses ◽  
Cellular Events ◽  
Bona Fide

AbstractObjectivesIdentification of osteoarthritis(OA)-specific synovial inflammatory pathways, and when in the clinical course they are active, is critical for their utility as therapeutic targets. We directly compared the mononuclear inflammatory/immune-cell responses following joint injury that does and does-not lead to OA, to define bona-fide OA-associated cellular events.MethodsWe undertook detailed temporal flow-cytometric and mRNA expression analysis in mice after sham or medial-meniscal-destiblization (DMM) surgery. We compared this with patients with meniscal injury and OA, and evaluated the role of synovial monocytes/macrophages versus lymphocytes in catabolic metalloproteinase secrection in vitro. We determined the effect of transient acute or delayed systemic T-cell depletion on DMM-induced OA pathology.ResultsOA-inducing/DMM and non-OA-inducing/Sham surgery had identical synovial monocyte/macrophage number, activation and polarization. The number and activation of synovial (not splenic or peripheral-blood) CD4 and CD8 lymphocytes was increased from 1-day after DMM versus Sham, and showed a persistent cyclical elevation throughout OA onset and progression. There was a temporal imbalance in synovial Th17/Treg and Th1/Th2 lymphocytes during DMM-induced OA initiation and progression. We confirmed early post-injury and late-OA CD3/CD8 T-cell responses in synovial tissues from patients, identified an association between CD8 and early post-injury symptoms, and defined a significant role for CD3+T-cells in synovial metalloproteinase secretion. Anti-CD3 cell-depletion studies in mice confirmed a key role for the earliest post-injury T-cell response in long-term OA pathology.ConclusionsWe identify a hitherto unappreciated pathophysiological role of acute T-cell activation after joint injury in long-term post-traumatic OA risk, providing a novel diagnostic and therapeutic target.Key MessagesWhat is already known about this subject?The presence of synovitis/joint-inflammation increases the risk not only of osteoarthritis (OA) progression but incident disease. While numerous inflammatory effectors including macrophages and lymphocytes have been identified in OA, their disease-specificity, temporal regulation, and association with risk of pathology onset and progression is lacking.How does this study add?By directly comparing the mononuclear inflammatory/immune-cell responses following significant joint injury that does (medial-meniscal-destabilization; DMM) and does-not (Sham-surgery) lead to OA in mice, we have defined bona-fide OA-associated cellular events. There was no difference in synovial or systemic monocyte/macrophage cell number, activation or polarization between DMM and Sham, both showing a successful wound-healing response. In contrast, increases in number and activation of synovial Th1- and Th17-CD4, and CD8 T-cells in DMM compared with Sham occurred within the first 3 days, and while recurring cyclically through subsequent disease onset, depletion studies indicated this initial influx was key to long-term ptOA risk.How might this impact on clinical practice of future developments?Acute increases in synovial T-cells following jont injury may be both a novel marker of OA risk, and a target to reduce long term structural damage.

scholarly journals HIV-specific T-cell Responses and Generalized Activation in HIV-1 Infected Long-term Non-progressors and Progressors from South India

2019 ◽  
Vol 16 (4) ◽  
pp. 302-314
Author(s):  
Chinnambedu Ravichandran Swathirajan ◽  
Ramachandran Vignesh ◽  
Greer Waldrop ◽  
Uma Shanmugasundaram ◽  
Pannerselvam Nandagopal ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
T Cell Activation ◽  
Cell Activation ◽  
Cd4 T Cell ◽  
Cell Responses ◽  
Activation Rates ◽  
Hiv 1

Background:Anti-viral cytokine expressions by cytotoxic T-cells and lower activation rates have been reported to correlate with suppressed HIV replication in long-term non-progressors (LTNP). Immune mechanisms underlying disease non-progression in LTNP might vary with HIV-1 subtype and geographical locations.Objective:This study evaluates cytokine expression and T-cells activation in relation to disease non-progression in LTNP.Methods:HIV-1 Subtype C infected LTNP (n=20) and progressors (n=15) were enrolled and flowcytometry assays were performed to study HIV-specific CD8 T-cells expressing IL-2, IFN-γ, TNF-α and MIP-1β against gag and env peptides. CD4+ T-cell activation was evaluated by surface expression of HLADR and CD38.Results:Proportions of cytokines studied did not differ significantly between LTNP and progressors, while contrasting correlations with disease progression markers were observed in LTNP. CD4+ T-cell activation rates were significantly lower in LTNP compared to progressors which indicate the potential role of T-cell activation rates in disease non-progression in LTNP.Conclusion:LTNP and progressors showed similar CD8+ T-cell responses, but final conclusions can be drawn only by comparing multiple immune factors in larger LTNP cohort with HIV-1 infected individuals at various levels of disease progression. A possible role of HIV-1 subtype variation and ethnic differences in addition to host-genetic and viral factors cannot be ruled out.

scholarly journals T cell–specific STAT3 deficiency abrogates lupus nephritis

Lupus ◽  
2019 ◽  
Vol 28 (12) ◽  
pp. 1468-1472 ◽  
Author(s):  
N Yoshida ◽  
F He ◽  
V C Kyttaris
Keyword(s):  
T Cells ◽  
T Cell ◽  
Lupus Nephritis ◽  
Lupus Erythematosus ◽  
Cell Responses ◽  
Cytokines And Chemokines ◽  
Novel Approach ◽  
Cell Tissue ◽  
External Stimuli

Signal transducer and activator of transcription (STAT) 3 is a regulator of T-cell responses to external stimuli, such as pro-inflammatory cytokines and chemokines. We have previously shown that STAT3 is activated (phosphorylated) at high levels in systemic lupus erythematosus (SLE) T cells and mediates chemokine-induced migration and T:B cell interactions. Stattic, a small molecular STAT3 inhibitor, can partially ameliorate lupus nephritis in mice. To understand the role of STAT3 better in T-cell pathophysiology in lupus nephritis and its potential as a treatment target, we silenced its expression in T cells using a cd4-driven CRE-Flox model. We found that lupus-prone mice that do not express STAT3 in T cells did not develop lymphadenopathy, splenomegaly, or glomerulonephritis. Moreover, the production of anti-dsDNA antibodies was decreased in these mice compared to controls. To dissect the mechanism, we also used a nephrotoxic serum model of nephritis. In this model, T cell–specific silencing of STAT3 resulted in amelioration of nephrotoxic serum-induced kidney damage. Taken together, our results suggest that in mouse models of autoimmune nephritis, T cell–specific silencing of STAT3 can hamper their ability to help B cells to produce autoantibodies and induce cell tissue infiltration. We propose that STAT3 inhibition in T cells represents a novel approach in the treatment of SLE and lupus nephritis in particular.

scholarly journals Long-Term Immunity to Trypanosoma cruzi in the Absence of Immunodominanttrans-Sialidase-Specific CD8+T Cells

2016 ◽  
Vol 84 (9) ◽  
pp. 2627-2638 ◽  
Author(s):  
Charles S. Rosenberg ◽  
Weibo Zhang ◽  
Juan M. Bustamante ◽  
Rick L. Tarleton
Keyword(s):  
T Cells ◽  
T Cell ◽  
Transgenic Mice ◽  
Trypanosoma Cruzi ◽  
T Cell Responses ◽  
Content Type ◽  
Cell Responses ◽  
Pathogen Control ◽  
Immunodominant Epitopes

Trypanosoma cruziinfection drives the expansion of remarkably focused CD8+T cell responses targeting epitopes encoded by varianttrans-sialidase (TS) genes. Infection of C57BL/6 mice withT. cruziresults in up to 40% of all CD8+T cells committed to recognition of the dominant TSKB20 and subdominant TSKB18 TS epitopes. However, despite this enormous response, these mice fail to clearT. cruziinfection and subsequently develop chronic disease. One possible reason for the failure to cureT. cruziinfection is that immunodomination by these TS-specific T cells may interfere with alternative CD8+T cell responses more capable of complete parasite elimination. To address this possibility, we created transgenic mice that are centrally tolerant to these immunodominant epitopes. Mice expressing TSKB20, TSKB18, or both epitopes controlledT. cruziinfection and developed effector CD8+T cells that maintained an activated phenotype. Memory CD8+T cells from drug-cured TSKB-transgenic mice rapidly responded to secondaryT. cruziinfection. In the absence of the response to TSKB20 and TSKB18, immunodominance did not shift to other known subdominant epitopes despite the capacity of these mice to expand epitope-specific T cells specific for the model antigen ovalbumin expressed by engineered parasites. Thus, CD8+T cell responses tightly and robustly focused on a few epitopes within variant TS antigens appear to neither contribute to, nor detract from, the ability to controlT. cruziinfection. These data also indicate that the relative position of an epitope within a CD8+immunodominance hierarchy does not predict its importance in pathogen control.

scholarly journals m6A demethylase ALKBH5 controls CD4+ T cell pathogenicity and promotes autoimmunity

2021 ◽  
Vol 7 (25) ◽  
pp. eabg0470
Author(s):  
Jing Zhou ◽  
Xingli Zhang ◽  
Jiajia Hu ◽  
Rihao Qu ◽  
Zhibin Yu ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Messenger Rna ◽  
Interferon Γ ◽  
Autoimmune Encephalomyelitis ◽  
Cell Responses ◽  
Chemokine Ligand ◽  
The Central Nervous System ◽  
Chemokine Ligand 2

N6-methyladenosine (m6A) modification is dynamically regulated by “writer” and “eraser” enzymes. m6A “writers” have been shown to ensure the homeostasis of CD4+ T cells, but the “erasers” functioning in T cells is poorly understood. Here, we reported that m6A eraser AlkB homolog 5 (ALKBH5), but not FTO, maintains the ability of naïve CD4+ T cells to induce adoptive transfer colitis. In addition, T cell–specific ablation of ALKBH5 confers protection against experimental autoimmune encephalomyelitis. During the induced neuroinflammation, ALKBH5 deficiency increased m6A modification on interferon-γ and C-X-C motif chemokine ligand 2 messenger RNA (mRNA), thus decreasing their mRNA stability and protein expression in CD4+ T cells. These modifications resulted in attenuated CD4+ T cell responses and diminished recruitment of neutrophils into the central nervous system. Our findings reveal an unexpected specific role of ALKBH5 as an m6A eraser in controlling the pathogenicity of CD4+ T cells during autoimmunity.

scholarly journals Vaccinia-specific cytotoxic T-cell responses in the context of H-2 antigens not encountered in thymus may reflect aberrant recognition of a virus-H-2 complex.

1979 ◽  
Vol 149 (1) ◽  
pp. 150-157 ◽  
Author(s):  
P C Doherty ◽  
J C Bennink
Keyword(s):  
T Cells ◽  
T Cell ◽  
Vaccinia Virus ◽  
T Cell Responses ◽  
Cytotoxic T Cell ◽  
Cell Responses ◽  
Antigen Complex ◽  
Infected Cells ◽  
Cytotoxic T Cell Responses

BALB/c (H-2Kd-Dd) spleen and lymph node populations were specifically depleted of alloreactive potential by filtration through H-2 different, irradiated recipients. These negatively selected T cells were then stimulated with vaccinia virus in mice expressing the foreign H-2 determinants encountered previously in the filter environment. Strong virus-immune cytotoxic T-cell responses were seen in the context of H-2Kk and H-2Ks, but not 2H-2Kb. The T cells generated were not cross-reactive for the H-2Kk and H-2Kd alleles, and responsiveness was independent of concurrent presence of effector populations operating at H-2D. These findings are consisent with the idea that recognition is mediated via a complex receptor, part of which is specific for virus and part for self H-2. The capacity to interact with allogeneic, virus-infected cells may then reflect aberrant recognition of a virus-H-2-antigen complex by this single, large binding site. For instance, the T cell which would normally recognize H-2Kd-virus x, or H-2Dd-minor histocompatibility antigen Z, may now show specificity for H-2Kk-vaccinia virus. Implications for both the selective role of the thymus and for mechanisms of tolerance are discussed.

scholarly journals T cell-intrinsic role of IL-6 signaling in primary and memory responses

eLife ◽  
2014 ◽  
Vol 3 ◽  
Author(s):  
Simone A Nish ◽  
Dominik Schenten ◽  
F Thomas Wunderlich ◽  
Scott D Pope ◽  
Yan Gao ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Suppressive Effect ◽  
Immune Recognition ◽  
Th17 Response ◽  
Cell Responses ◽  
Underlying Mechanisms ◽  
Specific Deletion

Innate immune recognition is critical for the induction of adaptive immune responses; however the underlying mechanisms remain incompletely understood. In this study, we demonstrate that T cell-specific deletion of the IL-6 receptor α chain (IL-6Rα) results in impaired Th1 and Th17 T cell responses in vivo, and a defect in Tfh function. Depletion of Tregs in these mice rescued the Th1 but not the Th17 response. Our data suggest that IL-6 signaling in effector T cells is required to overcome Treg-mediated suppression in vivo. We show that IL-6 cooperates with IL-1β to block the suppressive effect of Tregs on CD4+ T cells, at least in part by controlling their responsiveness to IL-2. In addition, although IL-6Rα-deficient T cells mount normal primary Th1 responses in the absence of Tregs, they fail to mature into functional memory cells, demonstrating a key role for IL-6 in CD4+ T cell memory formation.

scholarly journals HIV-1 Viremia Prevents the Establishment of Interleukin 2–producing HIV-specific Memory CD4+ T Cells Endowed with Proliferative Capacity

2003 ◽  
Vol 198 (12) ◽  
pp. 1909-1922 ◽  
Author(s):  
Souheil-Antoine Younes ◽  
Bader Yassine-Diab ◽  
Alain R. Dumont ◽  
Mohamed-Rachid Boulassel ◽  
Zvi Grossman ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cd4 T Cells ◽  
Cd4 T Cell ◽  
Memory Cells ◽  
Cell Responses ◽  
Specific Memory ◽  
Ifn Γ ◽  
Memory Cd4 T Cells

CD4+ T cell responses are associated with disease control in chronic viral infections. We analyzed human immunodeficiency virus (HIV)-specific responses in ten aviremic and eight viremic patients treated during primary HIV-1 infection and for up to 6 yr thereafter. Using a highly sensitive 5-(and-6)-carboxyfluorescein diacetate-succinimidyl ester–based proliferation assay, we observed that proliferative Gag and Nef peptide-specific CD4+ T cell responses were 30-fold higher in the aviremic patients. Two subsets of HIV-specific memory CD4+ T cells were identified in aviremic patients, CD45RA− CCR7+ central memory cells (Tcm) producing exclusively interleukin (IL)-2, and CD45RA− CCR7− effector memory cells (Tem) that produced both IL-2 and interferon (IFN)-γ. In contrast, in viremic, therapy-failing patients, we found significant frequencies of Tem that unexpectedly produced exclusively IFN-γ. Longitudinal analysis of HIV epitope–specific CD4+ T cells revealed that only cells that had the capacity to produce IL-2 persisted as long-term memory cells. In viremic patients the presence of IFN-γ–producing cells was restricted to periods of elevated viremia. These findings suggest that long-term CD4+ T cell memory depends on IL-2–producing CD4+ T cells and that IFN-γ only–producing cells are short lived. Our data favor a model whereby competent HIV-specific Tcm continuously arise in small numbers but under persistent antigenemia are rapidly induced to differentiate into IFN-γ only–producing cells that lack self-renewal capacity.

scholarly journals Long-Term Control of Simian Immunodeficiency Virus (SIV) in Cynomolgus Macaques Not Associated with Efficient SIV-Specific CD8+T-Cell Responses

2015 ◽  
Vol 89 (7) ◽  
pp. 3542-3556 ◽  
Author(s):  
Timothée Bruel ◽  
Chiraz Hamimi ◽  
Nathalie Dereuddre-Bosquet ◽  
Antonio Cosma ◽  
So Youn Shin ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
T Cell Activation ◽  
T Cell Responses ◽  
Cell Depletion ◽  
Viral Control ◽  
Cell Responses ◽  
Cynomolgus Macaques ◽  
Hiv 1

ABSTRACTThe spontaneous control of human and simian immunodeficiency viruses (HIV/SIV) is typically associated with specific major histocompatibility complex (MHC) class I alleles and efficient CD8+T-cell responses, but many controllers maintain viral control despite a nonprotective MHC background and weak CD8+T-cell responses. Therefore, the contribution of this response to maintaining long-term viral control remains unclear. To address this question, we transiently depleted CD8+T cells from five SIV-infected cynomolgus macaques with long-term viral control and weak CD8+T-cell responses. Among them, only one carried the protective MHC allele H6. After depletion, four of five controllers experienced a transient rebound of viremia. The return to undetectable viremia was accompanied by only modest expansion of SIV-specific CD8+T cells that lacked efficient SIV suppression capacityex vivo. In contrast, the depletion was associated with homeostatic activation/expansion of CD4+T cells that correlated with viral rebound. In one macaque, viremia remained undetectable despite efficient CD8+cell depletion and inducible SIV replication from its CD4+T cellsin vitro. Altogether, our results suggest that CD8+T cells are not unique contributors to the long-term maintenance of low viremia in this SIV controller model and that other mechanisms, such as weak viral reservoirs or control of activation, may be important players in control.IMPORTANCESpontaneous control of HIV-1 to undetectable levels is associated with efficient anti-HIV CD8+T-cell responses. However, in some cases, this response fades over time, although viral control is maintained, and many HIV controllers (weak responders) have very low frequencies of HIV-specific CD8+T cells. In these cases, the importance of CD8 T cells in the maintenance of HIV-1 control is questionable. We developed a nonhuman primate model of durable SIV control with an immune profile resembling that of weak responders. Transient depletion of CD8+cells induced a rise in the viral load. However, viremia was correlated with CD4+T-cell activation subsequent to CD8+cell depletion. Regain of viral control to predepletion levels was not associated with restoration of the anti-SIV capacities of CD8+T cells. Our results suggest that CD8+T cells may not be involved in maintenance of viral control in weak responders and highlight the fact that additional mechanisms should not be underestimated.

scholarly journals Impaired response to Listeria in H2-M3–deficient mice reveals a nonredundant role of MHC class Ib–specific T cells in host defense

2006 ◽  
Vol 203 (2) ◽  
pp. 449-459 ◽  
Author(s):  
Honglin Xu ◽  
Taehoon Chun ◽  
Hak-Jong Choi ◽  
Bin Wang ◽  
Chyung-Ru Wang
Keyword(s):  
T Cells ◽  
T Cell ◽  
Host Defense ◽  
Cd8 T Cells ◽  
Mhc Class Ib ◽  
Cell Responses ◽  
Mhc Class Ia ◽  
Deficient Mice ◽  
Class Ib

The major histocompatibility complex (MHC) class Ib molecule H2-M3 primes the rapid expansion of CD8+ T cells by presenting N-formylated bacterial peptides. However, the significance of H2-M3–restricted T cells in host defense against bacteria is unclear. We generated H2-M3–deficient mice to investigate the role of H2-M3 in immunity against Listeria monocytogenes (LM), a model intracellular bacterial pathogen. H2-M3–deficient mice are impaired in early bacterial clearance during primary infection, with diminished LM-specific CD8+ T cell responses and compromised innate immune functions. Although H2-M3–restricted CD8+ T cells constitute a significant proportion of the anti-listerial CD8+ T cell repertoire, the kinetics and magnitude of MHC class Ia–restricted T cell responses are not altered in H2-M3–deficient mice. The fact that MHC class Ia–restricted responses cannot compensate for the H2-M3–mediated immunity suggests a nonredundant role of H2-M3 in the protective immunity against LM. Thus, the early H2-M3–restricted response temporally bridges the gap between innate and adaptive immune responses, subsequently affecting the function of both branches of the immune system.

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