scholarly journals Restricting Zap70 Expression to CD4+CD8+ Thymocytes Reveals a T Cell Receptor–dependent Proofreading Mechanism Controlling the Completion of Positive Selection

2003 ◽  
Vol 197 (3) ◽  
pp. 363-373 ◽  
Author(s):  
Xiaolong Liu ◽  
Anthony Adams ◽  
Kathryn F. Wildt ◽  
Bruce Aronow ◽  
Lionel Feigenbaum ◽  
...  
Keyword(s):  
T Cell ◽  
Positive Selection ◽  
T Cell Receptor ◽  
Cell Receptor ◽  
Thymocyte Development ◽  
Tcr Signaling ◽  
Novel Approach ◽  
Single Positive ◽  
Tcr Signals

Although T cell receptor (TCR) signals are essential for intrathymic T cell–positive selection, it remains controversial whether they only serve to initiate this process, or whether they are required throughout to promote thymocyte differentiation and survival. To address this issue, we have devised a novel approach to interfere with thymocyte TCR signaling in a developmental stage-specific manner in vivo. We have reconstituted mice deficient for Zap70, a tyrosine kinase required for TCR signaling and normally expressed throughout T cell development, with a Zap70 transgene driven by the adenosine deaminase (ADA) gene enhancer, which is active in CD4+CD8+ thymocytes but inactive in CD4+ or CD8+ single-positive (SP) thymocytes. In such mice, termination of Zap70 expression impaired TCR signal transduction and arrested thymocyte development after the initiation, but before the completion, of positive selection. Arrested thymocytes had terminated Rag gene expression and up-regulated TCR and Bcl-2 expression, but failed to differentiate into mature CD4 or CD8 SP thymocytes, to be rescued from death by neglect or to sustain interleukin 7Rα expression. These observations identify a TCR-dependent proofreading mechanism that verifies thymocyte TCR specificity and differentiation choices before the completion of positive selection.

scholarly journals Thymic progenitors of TCRαβ+ CD8αα intestinal intraepithelial lymphocytes require RasGRP1 for development

2017 ◽  
Vol 214 (8) ◽  
pp. 2421-2435 ◽  
Author(s):  
Dominic P. Golec ◽  
Romy E. Hoeppli ◽  
Laura M. Henao Caviedes ◽  
Jillian McCann ◽  
Megan K. Levings ◽  
...  
Keyword(s):  
T Cell ◽  
Positive Selection ◽  
Cell Receptor ◽  
Intraepithelial Lymphocytes ◽  
Thymocyte Development ◽  
Tcr Signaling ◽  
Clonal Deletion ◽  
Selection Processes ◽  
Tcr Signals

Strong T cell receptor (TCR) signaling largely induces cell death during thymocyte development, whereas weak TCR signals induce positive selection. However, some T cell lineages require strong TCR signals for differentiation through a process termed agonist selection. The signaling relationships that underlie these three fates are unknown. RasGRP1 is a Ras activator required to transmit weak TCR signals leading to positive selection. Here, we report that, despite being dispensable for thymocyte clonal deletion, RasGRP1 is critical for agonist selection of TCRαβ+CD8αα intraepithelial lymphocyte (IEL) progenitors (IELps), even though both outcomes require strong TCR signaling. Bim deficiency rescued IELp development in RasGRP1−/− mice, suggesting that RasGRP1 functions to promote survival during IELp generation. Additionally, expression of CD122 and the adhesion molecules α4β7 and CD103 define distinct IELp subsets with differing abilities to generate TCRαβ+CD8αα IEL in vivo. These findings demonstrate that RasGRP1-dependent signaling underpins thymic selection processes induced by both weak and strong TCR signals and is differentially required for fate decisions derived from a strong TCR stimulus.

scholarly journals Loss of tonic T-cell receptor signals alters the generation but not the persistence of CD8+ memory T cells

Blood ◽  
2010 ◽  
Vol 116 (25) ◽  
pp. 5560-5570 ◽  
Author(s):  
Karla R. Wiehagen ◽  
Evann Corbo ◽  
Michelle Schmidt ◽  
Haina Shin ◽  
E. John Wherry ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
T Cell Receptor ◽  
Cell Receptor ◽  
Lymphocytic Choriomeningitis ◽  
Sh2 Domain ◽  
Normal Numbers ◽  
Tcr Signaling ◽  
Tcr Signals

Abstract The requirements for tonic T-cell receptor (TCR) signaling in CD8+ memory T-cell generation and homeostasis are poorly defined. The SRC homology 2 (SH2)-domain–containing leukocyte protein of 76 kDa (SLP-76) is critical for proximal TCR-generated signaling. We used temporally mediated deletion of SLP-76 to interrupt tonic and activating TCR signals after clearance of the lymphocytic choriomeningitis virus (LCMV). SLP-76–dependent signals are required during the contraction phase of the immune response for the normal generation of CD8 memory precursor cells. Conversely, LCMV-specific memory CD8 T cells generated in the presence of SLP-76 and then acutely deprived of TCR-mediated signals persist in vivo in normal numbers for more than 40 weeks. Tonic TCR signals are not required for the transition of the memory pool toward a central memory phenotype, but the absence of SLP-76 during memory homeostasis substantially alters the kinetics. Our data are consistent with a model in which tonic TCR signals are required at multiple stages of differentiation, but are dispensable for memory CD8 T-cell persistence.

scholarly journals Conditional Knockout Mice Reveal an Essential Role of Protein Phosphatase 4 in Thymocyte Development and Pre-T-Cell Receptor Signaling

2006 ◽  
Vol 27 (1) ◽  
pp. 79-91 ◽  
Author(s):  
Jr-Wen Shui ◽  
Mickey C.-T. Hu ◽  
Tse-Hua Tan
Keyword(s):  
T Cell ◽  
T Cell Receptor ◽  
Okadaic Acid ◽  
Protein Phosphatase ◽  
Cell Receptor ◽  
Conditional Knockout ◽  
Thymocyte Development ◽  
Tcr Signaling ◽  
Deficient Mice

ABSTRACT Okadaic acid-sensitive serine/threonine phosphatases have been shown to regulate interleukin-2 transcription and T-cell activation. Okadaic acid inhibits protein phosphatase 4 (PP4), a novel PP2A-related serine/threonine phosphatase, at a 50% inhibitory concentration (IC50) comparable to that for PP2A. This raises the possibility that some cellular functions of PP2A, determined in T cells by using okadaic acid, may in fact be those of PP4. To investigate the in vivo roles of PP4 in T cells, we generated conventional and T-cell-specific PP4 conditional knockout mice. We found that the ablation of PP4 led to the embryonic lethality of mice. PP4 gene deletion in the T-cell lineage resulted in aberrant thymocyte development, including T-cell arrest at the double-negative 3 stage (CD4− CD8− CD25+ CD44−), abnormal thymocyte maturation, and lower efficacy of positive selection. PP4-deficient thymocytes showed decreased proliferation and enhanced apoptosis in vivo. Analysis of pre-T-cell receptor (pre-TCR) signaling further revealed impaired calcium flux and phospholipase C-γ1-extracellular signal-regulated kinase activation in the absence of PP4. Anti-CD3 injection in PP4-deficient mice led to enhanced thymocyte apoptosis, accompanied by increased proapoptotic Bim but decreased antiapoptotic Bcl-xL protein levels. In the periphery, antigen-specific T-cell proliferation and T-cell-mediated immune responses in PP4-deficient mice were dramatically compromised. Thus, our results indicate that PP4 is essential for thymocyte development and pre-TCR signaling.

scholarly journals A Kinetic Threshold between Negative and Positive Selection Based on the Longevity of the T Cell Receptor–Ligand Complex

1999 ◽  
Vol 189 (10) ◽  
pp. 1531-1544 ◽  
Author(s):  
Calvin B. Williams ◽  
Deborah L. Engle ◽  
Gilbert J. Kersh ◽  
J. Michael White ◽  
Paul M. Allen
Keyword(s):  
T Cells ◽  
T Cell ◽  
Positive Selection ◽  
T Cell Receptor ◽  
Cell Receptor ◽  
Ligand Complex ◽  
Altered Peptide Ligands ◽  
Self Peptides ◽  
Selection Of

We have developed a unique in vivo system to determine the relationship between endogenous altered peptide ligands and the development of major histocompatibility complex class II– restricted T cells. Our studies use the 3.L2 T cell receptor (TCR) transgenic mouse, in which T cells are specific for Hb(64–76)/I-Ek and positively selected on I-Ek plus self-peptides. To this endogenous peptide repertoire, we have individually added one of six well-characterized 3.L2 ligands. This transgenic approach expands rather than constrains the repertoire of self-peptides. We find that a broad range of ligands produce negative selection of thymocytes in vivo. When compared with the in vitro TCR–ligand binding kinetics, we find that these negatively selecting ligands all have a half-life of 2 s or greater. Additionally, one of two ligands examined with no detectable binding to the 3.L2 TCR and no activity on mature 3.L2 T cells (Q72) enhances the positive selection of transgenic thymocytes in vivo. Together, these data establish a kinetic threshold between negative and positive selection based on the longevity of TCR–ligand complexes.

scholarly journals A Novel Approach for the Treatment of T Cell Malignancies: Targeting T Cell Receptor Vβ Families

Vaccines ◽  
2020 ◽  
Vol 8 (4) ◽  
pp. 631
Author(s):  
Jie Wang ◽  
Katarzyna Urbanska ◽  
Prannda Sharma ◽  
Reza Nejati ◽  
Lauren Shaw ◽  
...  
Keyword(s):  
Monoclonal Antibody ◽  
T Cells ◽  
T Cell ◽  
T Cell Receptor ◽  
Cell Receptor ◽  
T Cell Lymphomas ◽  
Novel Approach ◽  
T Cell Malignancies

Peripheral T cell lymphomas (PTCLs) are generally chemotherapy resistant and have a poor prognosis. The lack of targeted immunotherapeutic approaches for T cell malignancies results in part from potential risks associated with targeting broadly expressed T cell markers, namely T cell depletion and clinically significant immune compromise. The knowledge that the T cell receptor (TCR) β chain in human α/β TCRs are grouped into Vβ families that can each be targeted by a monoclonal antibody can therefore be exploited for therapeutic purposes. Here, we develop a flexible approach for targeting TCR Vβ families by engineering T cells to express a chimeric CD64 protein that acts as a high affinity immune receptor (IR). We found that CD64 IR-modified T cells can be redirected with precision to T cell targets expressing selected Vβ families by combining CD64 IR-modified T cells with a monoclonal antibody directed toward a specific TCR Vβ family in vitro and in vivo. These findings provide proof of concept that TCR Vβ-family-specific T cell lysis can be achieved using this novel combination cell–antibody platform and illuminates a path toward high precision targeting of T cell malignancies without substantial immune compromise.

scholarly journals Pre–T Cell Receptor (Tcr) and Tcr-Controlled Checkpoints in T Cell Differentiation Are Set by Ikaros

1999 ◽  
Vol 190 (8) ◽  
pp. 1039-1048 ◽  
Author(s):  
Susan Winandy ◽  
Li Wu ◽  
Jin-Hong Wang ◽  
Katia Georgopoulos
Keyword(s):  
Cell Differentiation ◽  
T Cell ◽  
T Cell Receptor ◽  
Cell Receptor ◽  
T Cell Differentiation ◽  
Tcr Signaling ◽  
Double Positive ◽  
Single Positive ◽  
T Cell Malignancies ◽  
Deficient Mice

T cell differentiation relies on pre–T cell receptor (TCR) and TCR signaling events that take place at successive steps of the pathway. Here, we show that two of these T cell differentiation checkpoints are regulated by Ikaros. In the absence of Ikaros, double negative thymocytes can differentiate to the double positive stage without expression of a pre-TCR complex. Subsequent events in T cell development mediated by TCR involving transition from the double positive to the single positive stage are also regulated by Ikaros. Nonetheless, in Ikaros-deficient thymocytes, the requirement of pre-TCR expression for expansion of immature thymocytes as they progress to the double positive stage is still maintained, and the T cell malignancies that invariably arise in the thymus of Ikaros-deficient mice are dependent on either pre-TCR or TCR signaling. We conclude that Ikaros regulates T cell differentiation, selection, and homeostasis by providing signaling thresholds for pre-TCR and TCR.

scholarly journals The transcription factor Gli3 regulates differentiation of fetal CD4–CD8– double-negative thymocytes

Blood ◽  
2005 ◽  
Vol 106 (4) ◽  
pp. 1296-1304 ◽  
Author(s):  
Ariadne L. Hager-Theodorides ◽  
Johannes T. Dessens ◽  
Susan V. Outram ◽  
Tessa Crompton
Keyword(s):  
Transcription Factor ◽  
T Cell ◽  
T Cell Receptor ◽  
Cell Receptor ◽  
T Cell Differentiation ◽  
Double Negative ◽  
Thymocyte Development ◽  
Tcr Signaling ◽  
Double Positive ◽  
Dose Dependent

AbstractGlioblastoma 3 (Gli3) is a transcription factor involved in patterning and oncogenesis. Here, we demonstrate a role for Gli3 in thymocyte development. Gli3 is differentially expressed in fetal CD4–CD8– double-negative (DN) thymocytes and is most highly expressed at the CD44+ CD25– DN (DN1) and CD44–CD25– (DN4) stages of development but was not detected in adult thymocytes. Analysis of null mutants showed that Gli3 is involved at the transitions from DN1 to CD44+ CD25+ DN (DN2) cell and from DN to CD4+CD8+ double-positive (DP) cell. Gli3 is required for differentiation from DN to DP thymocyte, after pre–T-cell receptor (TCR) signaling but is not necessary for pre-TCR–induced proliferation or survival. The effect of Gli3 was dose dependent, suggesting its direct involvement in the transcriptional regulation of genes controlling T-cell differentiation during fetal development.

scholarly journals Early Deletion and Late Positive Selection of T-Cells Expressing a Male-Specific Receptor in T-Cell Receptor Transgenic Mice

1990 ◽  
Vol 1 (1) ◽  
pp. 1-10 ◽  
Author(s):  
Hung Sia Teh ◽  
Hiroyuki Kishi ◽  
Bernadette Scott ◽  
Peter Borgulya ◽  
Harald Von Boehmer ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Transgenic Mice ◽  
Positive Selection ◽  
T Cell Receptor ◽  
Interleukin 2 ◽  
Cell Receptor ◽  
Early Expression ◽  
Single Positive ◽  
Selection Of

The ontogeny of T cells in T-cell receptor (TCR) transgenic mice, which express a transgenicαβheterodimer, specific for the male (H-Y) antigen in association with H-2Db, was determined. The transgenicαchain was expressed on about 10% of the fetal thymocytes on day 14 of gestation. About 50% of day-15 fetal thymocytes expressed bothαandβtranschains and virtually all fetal thymocytes expressed the transgenicαβheterodimer by day 17. The early expression of the transgenic TCR on CD4-8-thymocytes prevented the development ofγδcells, and led to accelerated growth of thymocytes and an earlier expression of CD4 and CD8 molecules. Up to day 17, no significant differences in T-cell development could be detected between female and male thymuses. By day 18 of gestation, the male transgenic thymus contained more CD4-8-thymocytes than the female transgenic thymus. The preponderance of CD4-8-thymocytes in the male transgenic thymus increased until birth and was a consequence of the deletion of the CD4+8+thymocytes and their CD4-8+precursors. By the time of birth, the male transgenic thymus contained half the number of cells as the female transgenic thymus. The deletion of autospecific precursor cells in the male transgenic mouse began only at day 18 of gestation, despite the fact that the ligand could already be detected by day 16.The preferential accumulation of CD4-8+T cells, which expressed a high density of the transgenic TCR, occurred only after birth and was .obvious in 6-week-old female thymus. These data support the hypothesis that the positive selection of T cells expressing this transgenic heterodimer may involve two steps, i.e., the commitment of CD4+8+thymocytes to the CD4-8+lineage following the interaction of the transgenic TCR with restricting major histocompatibility molecules, followed by a slow conversion of CD4+8+thymocytes into CD4-8+T cells.In normal mice, the precursors of CD+4+8 and single positive thymocytes have the CD4-8-CD3-J11d+(or M1/69+) phenotype. Because of the early expression of the transgenicαβheterodimer, this population was not detected in adult transgenic mice. All CD4-8-M1/ 69+cells expressed the transgenic receptor associated with CD3 and could be readily grown in media containing T-cell lectins and interleukin 2.

scholarly journals Phosphorylation of a Tyrosine Residue on Zap70 by Lck and Its Subsequent Binding via an SH2 Domain May Be a Key Gatekeeper of T Cell Receptor SignalingIn Vivo

2016 ◽  
Vol 36 (18) ◽  
pp. 2396-2402 ◽  
Author(s):  
Peter A. Thill ◽  
Arthur Weiss ◽  
Arup K. Chakraborty
Keyword(s):  
T Cell ◽  
T Cell Receptor ◽  
Cell Receptor ◽  
Receptor Activation ◽  
Sh2 Domain ◽  
Tcr Signaling ◽  
New Model ◽  
Downstream Signaling ◽  
Conventional Models

The initiation of signaling in T lymphocytes in response to the binding of the T cell receptor (TCR) to cognate ligands is a key step in the emergence of adaptive immune responses. Conventional models posit that TCR signaling is initiated by the phosphorylation of receptor-associated immune receptor activation motifs (ITAMs). The cytoplasmic tyrosine kinase Zap70 binds to phosphorylated ITAMs, is subsequently activated, and then propagates downstream signaling. While evidence for such models is provided by experiments with cell lines,in vivo, Zap70 is bound to phosphorylated ITAMs in resting T cells. However, Zap70 is activated only upon TCR binding to cognate ligand. We report the results of computational studies of a new model for the initiation of TCR signaling that incorporates thesein vivoobservations. Importantly, the new model is shown to allow better and faster TCR discrimination between self-ligands and foreign ligands. The new model is consistent with many past experimental observations, and experiments that could further test the model are proposed.

scholarly journals Identification of a Late Stage of Small Noncycling pTα−  Pre-T Cells as Immediate Precursors of T Cell Receptor α/β+  Thymocytes

1998 ◽  
Vol 188 (8) ◽  
pp. 1401-1412 ◽  
Author(s):  
César Trigueros ◽  
Almudena R. Ramiro ◽  
Yolanda R. Carrasco ◽  
Virginia G. de Yebenes ◽  
Juan P. Albar ◽  
...  
Keyword(s):  
Gene Expression ◽  
T Cells ◽  
T Cell ◽  
T Cell Receptor ◽  
Cell Receptor ◽  
Developmental Model ◽  
Developmental Expression ◽  
Thymocyte Development ◽  
Cell Stage

During thymocyte development, progression from T cell receptor (TCR)β to TCRα rearrangement is mediated by a CD3-associated pre-TCR composed of the TCRβ chain paired with pre-TCRα (pTα). A major issue is how surface expression of the pre-TCR is regulated during normal thymocyte development to control transition through this checkpoint. Here, we show that developmental expression of pTα is time- and stage-specific, and is confined in vivo to a limited subset of large cycling human pre-T cells that coexpress low density CD3. This restricted expression pattern allowed the identification of a novel subset of small CD3− thymocytes lacking surface pTα, but expressing cytoplasmic TCRβ, that represent late noncycling pre-T cells in which recombination activating gene reexpression and downregulation of T early α transcription are coincident events associated with cell cycle arrest, and immediately preceding TCRα gene expression. Importantly, thymocytes at this late pre-T cell stage are shown to be functional intermediates between large pTα+ pre-T cells and TCRα/β+ thymocytes. The results support a developmental model in which pre-TCR–expressing pre-T cells are brought into cycle, rapidly downregulate surface pre-TCR, and finally become small resting pre-T cells, before the onset of TCRα gene expression.

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