Partial activation precedes apoptotic death in T cells harboring an IAN gene mutation

Lang, Julie; Kominski, Douglas; Bellgrau, Donald; Scheinman, Robert I.

doi:10.1002/eji.200324751

Cited by 24 publications

(23 citation statements)

References 20 publications

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“…Given the interesting role of another family member, Gimap5, in controlling T-cell homeostasis and diabetes mellitus in BioBreeding (BB) rats, [12][13][14][15][16][17][18] we have set out to define the function of Gimap4 in vitro and in vivo. Besides a GTPase domain, characteristic for all members within the gimap gene cluster, 19 other conserved protein motifs are proven to be functional.…”

Section: And Marsden and Strasser 5 )mentioning

confidence: 99%

Gimap4 accelerates T-cell death

Schnell

Démollière

Berk

et al. 2006

Blood

116

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Section: And Marsden and Strasser 5 )mentioning

confidence: 99%

Gimap4 accelerates T-cell death

Schnell

Démollière

Berk

et al. 2006

Blood

116

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“…It is now apparent that survival and quiescence are actively enforced in T cells (41)(42)(43)(44)(45)(46)(47). This paradigm has long been operative in other systems where survival requires signals from a substrate or matrix (avoidance of anoikis) (48,49) and where quiescence is enforced by signals delivered when cells contact each other (50).…”

Section: Intrinsic Negative Regulators Of T Cell Activationmentioning

confidence: 99%

“…Moreover, the phenotype is intrinsic to the T cells, as it occurs in bone marrow chimeras where Ian5 mutant T cells develop in a wild type environment (51). Thus, partial T cell activation in Ian5-deficient animals is not a consequence of lymphopenia but is rather part of the stimulus leading to cell death, providing one biochemical link between survival and quiescence pathways (42,51).…”

Section: Ian5 In Negative Regulation and Survivalmentioning

confidence: 99%

Negative regulators in homeostasis of naïve peripheral T cells

2008

Self Cite

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It is now apparent that naïve peripheral T cells are a dynamic population where active processes prevent inappropriate activation while supporting survival. The process of thymic education makes naïve peripheral T cells dependent on interactions with self-MHC for survival. However, as these signals can potentially result in inappropriate activation, various non-redundant, intrinsic negative regulatory molecules including Tob, Nfatc2, and Smad3 actively enforce T cell quiescence. Interactions among these pathways are only now coming to light and may include positive or negative crosstalk. In the case of positive crosstalk, self-MHC initiated signals and intrinsic negative regulatory factors may cooperate to dampen T cell activation and sustain peripheral tolerance in a binary fashion (on-off). In the case of negative crosstalk, self-MHC signals may promote survival through partial activation while intrinsic negative regulatory factors act as rheostats to restrain cell cycle entry and prevent T cells from crossing a threshold that would break tolerance. KeywordsT cells; MHC; sensitization; desensitization; cell cycle; negative regulation; tolerance The Influence of Self-MHC in T-Cell Quiescence and Survival Self-MHC and naïve T cell survivalThe role of self-peptides complexed to major histocompatibility complex proteins (self-MHC) to maintain homeostasis of naïve T cells has been the subject of extensive investigation over the past decade. This work has revealed apparent differences in the sensitivity of different T cell subsets to the absence of self-MHC. Perhaps the most informative experiments have attempted to characterize the expansion of peripheral lymphocytes in MHC-replete or MHCdeficient lymphopenic environments. The idea that "space" in the peripheral lymphoid organs drove lymphocyte proliferation arose from the observation that under conditions of lymphopenia such as those produced by non-myeloablative, lymphodepleting regimens in humans or mice, or under conditions encountered by adoptively transferred lymphocytes or bone marrow cells into lymphopenic hosts, T cells would expand without exogenous antigens. It is now apparent that this "lymphopenia-induced proliferation" or "homeostatic proliferation" (HP) results not only from "space", but also from interactions of T cell receptors (TCR) with self-MHC, and from lessened competition for cytokines including interleukin-7 (IL-7), or in some cases, Unlike HP in MHC-replete hosts, a majority of naïve T cells die or make at most a few divisions if the lymphopenic periphery is devoid of MHC (16-21), a result consistent with the premise that HP is itself partly driven by recognition of self-MHC complexes. Both CD4 and CD8 T cells undergo HP, although CD4 T cells expand less in response to MHC and CD8 T cells are more sensitive to its absence. In fact, while the requirement for self-MHC in naïve CD8 T cell survival is generally accepted (although it may not apply to all CD8 T cell subsets) (22), the delayed erosion of naïve CD4 T cells in lymphopenic h...

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“…The identification of the Gimap family of proteins and the potential to generate specific antibody reagents (27) should make it feasible to better dissect the series of events that preclude the survival of T-cells past the thymus. It cannot be excluded that cellular events preceding the spontaneous onset of diabetes may compromise the function of T-cells that survive the Gimap5 null allele (34). If that is the case, however, the process would have to be specific for diabetes, since all of the DRF.…”

Section: Lyp/lypmentioning

confidence: 99%