Activation-induced cell death in T cells.
TL;DR: This review addresses the phenomenon of activation‐induced cell death (AICD) in T lymphocytes, in which activation through the T‐cell receptor results in apoptosis.
Abstract: A properly functioning immune system is dependent on programmed cell death at virtually every stage of lymphocyte development and activity. This review addresses the phenomenon of activation-induced cell death (AICD) in T lymphocytes, in which activation through the T-cell receptor results in apoptosis. AICD can occur in a cell-autonomous manner and is influenced by the nature of the initial T-cell activation events. It plays essential roles in both central and peripheral deletion events involved in tolerance and homeostasis, although it is likely that different forms of AICD proceed via different mechanisms. For example, while AICD in peripheral T cells is often caused by the induction of expression of the death ligand, Fas ligand (CD95 ligand, FasL), it does not appear to be involved in AICD in thymocytes. This and other mechanisms of AICD are discussed. One emerging model that may complement other forms of AICD involves the inducible expression of FasL by nonlymphoid tissues in response to activated T lymphocytes. Induction of nonlymphoid FasL in this manner may serve as a sensing mechanism for immune cell infiltration, which contributes to peripheral deletion.
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TL;DR: This review highlights the findings that have advanced the understanding of TGF-beta in the immune system and in disease.
Abstract: Transforming growth factor-beta (TGF-beta) is a potent regulatory cytokine with diverse effects on hemopoietic cells. The pivotal function of TGF-beta in the immune system is to maintain tolerance via the regulation of lymphocyte proliferation, differentiation, and survival. In addition, TGF-beta controls the initiation and resolution of inflammatory responses through the regulation of chemotaxis, activation, and survival of lymphocytes, natural killer cells, dendritic cells, macrophages, mast cells, and granulocytes. The regulatory activity of TGF-beta is modulated by the cell differentiation state and by the presence of inflammatory cytokines and costimulatory molecules. Collectively, TGF-beta inhibits the development of immunopathology to self or nonharmful antigens without compromising immune responses to pathogens. This review highlights the findings that have advanced our understanding of TGF-beta in the immune system and in disease.
2,084 citations
TL;DR: In this article, the authors present methods of diagnosis by assessing B7-H1 expression in a tissue from a subject that has, or is suspected of having, cancer, methods of treatment with agents that interfere with B7H1-receptor interaction, and methods of selecting candidate subjects likely to benefit from cancer immunotherapy.
Abstract: The invention features methods of diagnosis by assessing B7-H1 expression in a tissue from a subject that has, or is suspected of having, cancer, methods of treatment with agents that interfere with B7-H1-receptor interaction, methods of selecting candidate subjects likely to benefit from cancer immunotherapy, and methods of inhibiting expression of B7-H1.
666 citations
TL;DR: Particular emphasis is given to how Se and selenoproteins are linked to redox signaling, oxidative burst, calcium flux, and the subsequent effector functions of immune cells, as well as the benefits and potential adverse effects of intervention with Se supplementation for various inflammatory or immune disorders.
Abstract: Dietary selenium (]Se), mainly through its incorporation into selenoproteins, plays an important role in inflammation and immunity. Adequate levels of Se are important for initiating immunity, but they are also involved in regulating excessive immune responses and chronic inflammation. Evidence has emerged regarding roles for individual selenoproteins in regulating inflammation and immunity, and this has provided important insight into mechanisms by which Se influences these processes. Se deficiency has long been recognized to negatively impact immune cells during activation, differentiation, and proliferation. This is related to increased oxidative stress, but additional functions such as protein folding and calcium flux may also be impaired in immune cells under Se deficient conditions. Supplementing diets with above-adequate levels of Se can also impinge on immune cell function, with some types of inflammation and immunity particularly affected and sexually dimorphic effects of Se levels in so...
612 citations
TL;DR: The concepts of activation-induced cell death (AICD) and activated cell-autonomous death (ACAD) in the regulation of life and death in T cells are discussed.
Abstract: During the course of an immune response, antigen-reactive T cells clonally expand and then are removed by apoptosis to maintain immune homeostasis. Life and death of T cells is determined by multiple factors, such as T-cell receptor triggering, co-stimulation or cytokine signalling, and by molecules, such as caspase-8 (FLICE)-like inhibitory protein (FLIP) and haematopoietic progenitor kinase 1 (HPK1), which regulate the nuclear factor-kappaB (NF-kappaB) pathway. Here, we discuss the concepts of activation-induced cell death (AICD) and activated cell-autonomous death (ACAD) in the regulation of life and death in T cells.
591 citations
Cites background from "Activation-induced cell death in T ..."
...Some findings suggest that TNF is involved in the late phase of AIC...
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References
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TL;DR: It is demonstrated that Akt also regulates the activity of FKHRL1, a member of the Forkhead family of transcription factors, which triggers apoptosis most likely by inducing the expression of genes that are critical for cell death, such as the Fas ligand gene.
6,481 citations
TL;DR: Recently, significant advances have been made in elucidating the details of the pathways through which signals are transmitted to the NF-kappa B:I kappa B complex in the cytosol and their implications for the study of NF-Kappa B.
Abstract: ▪ Abstract The transcription factor NF-κB, more than a decade after its discovery, remains an exciting and active area of study. The involvement of NF-κB in the expression of numerous cytokines and adhesion molecules has supported its role as an evolutionarily conserved coordinating element in the organism's response to situations of infection, stress, and injury. Recently, significant advances have been made in elucidating the details of the pathways through which signals are transmitted to the NF-κB:IκB complex in the cytosol. The field now awaits the discovery and characterization of the kinase responsible for the inducible phosphorylation of IκB proteins. Another exciting development has been the demonstration that in certain situations NF-κB acts as an anti-apoptotic protein; therefore, elucidation of the mechanism by which NF-κB protects against cell death is an important goal. Finally, the generation of knockouts of members of the NF-κB/IκB family has allowed the study of the roles of these protein...
5,324 citations
"Activation-induced cell death in T ..." refers background in this paper
...The transcription factor NF-kB is ubiquitously expressed and inducibly activated (109, 110)....
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TL;DR: In this paper, a review of recent progress as well as unanswered questions regarding the regulation and function of NF-kappaB and IKK is presented, focusing on recent progress and unanswered questions.
3,342 citations
TL;DR: It is demonstrated that deregulated c-myc expression induces apoptosis in cells growth arrested by a variety of means and at various points in the cell cycle.
3,047 citations
"Activation-induced cell death in T ..." refers background in this paper
...Evan and colleagues (11) demonstrated a pro-apoptotic role of c-Myc in the context of proliferation in fibroblasts, while Green et al....
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TL;DR: Tumor necrosis factor alpha binding to the TNF receptor (TNFR) potentially initiates apoptosis and activates the transcription factor nuclear factor kappa B (NF-kappaB), which suppresses apoptosis by an unknown mechanism.
Abstract: Tumor necrosis factor alpha (TNF-alpha) binding to the TNF receptor (TNFR) potentially initiates apoptosis and activates the transcription factor nuclear factor kappa B (NF-kappaB), which suppresses apoptosis by an unknown mechanism. The activation of NF-kappaB was found to block the activation of caspase-8. TRAF1 (TNFR-associated factor 1), TRAF2, and the inhibitor-of-apoptosis (IAP) proteins c-IAP1 and c-IAP2 were identified as gene targets of NF-kappaB transcriptional activity. In cells in which NF-kappaB was inactive, all of these proteins were required to fully suppress TNF-induced apoptosis, whereas c-IAP1 and c-IAP2 were sufficient to suppress etoposide-induced apoptosis. Thus, NF-kappaB activates a group of gene products that function cooperatively at the earliest checkpoint to suppress TNF-alpha-mediated apoptosis and that function more distally to suppress genotoxic agent-mediated apoptosis.
2,766 citations
"Activation-induced cell death in T ..." refers background in this paper
...These include TNFRassociated factor 1 (TRAF1) and TRAF2, and the c-IAPs (85), A20 (86), IEX (87), and A1/Bfl (88)....
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