scholarly journals Absence of ZAP-70 prevents signaling through the antigen receptor on peripheral blood T cells but not on thymocytes.

1995 ◽  
Vol 182 (4) ◽  
pp. 1057-1065 ◽  
Author(s):  
E W Gelfand ◽  
K Weinberg ◽  
B D Mazer ◽  
T A Kadlecek ◽  
A Weiss
Keyword(s):  
T Cells ◽  
Cd4 T Cells ◽  
Severe Combined Immunodeficiency ◽  
Thymic Selection ◽  
Tcr Signaling ◽  
Peripheral T Cells ◽  
Tcr Signal Transduction ◽  
Immunodeficiency Syndrome ◽  
Severe Combined Immunodeficiency Syndrome ◽  
Selection Of

Recently, a severe combined immunodeficiency syndrome with a deficiency of CD8+ peripheral T cells and a TCR signal transduction defect in peripheral CD4+ T cells was associated with mutations in ZAP-70. Since TCR signaling is required in developmental decisions resulting in mature CD4 (and CD8) T cells, the presence of peripheral CD4+ T cells expressing TCRs incapable of signaling in these patients is paradoxical. Here, we show that the TCRs on thymocytes, but not peripheral T cells, from a ZAP-70-deficient patient are capable of signaling. Moreover, the TCR on a thymocyte line derived from this patient can signal, and the homologous kinase Syk is present at high levels and is tyrosine phosphorylated after TCR stimulation. Thus, Syk may compensate for the loss of ZAP-70 and account for the thymic selection of at least a subset of T cells (CD4+) in ZAP-70-deficient patients.

scholarly journals Erythroid Differentiation Regulator 1 Strengthens TCR Signaling by Enhancing PLCγ1 Signal Transduction Pathway

2022 ◽  
Vol 23 (2) ◽  
pp. 844
Author(s):  
Myun Soo Kim ◽  
Dongmin Park ◽  
Sora Lee ◽  
Sunyoung Park ◽  
Kyung Eun Kim ◽  
...  
Keyword(s):  
Signal Transduction ◽  
T Cells ◽  
Cd4 T Cells ◽  
Signal Transduction Pathway ◽  
Erythroid Differentiation ◽  
Transduction Pathway ◽  
Tcr Signaling ◽  
Peripheral T Cells ◽  
Signal Regulation

Erythroid differentiation regulator 1 (Erdr1) has previously been reported to control thymocyte selection via TCR signal regulation, but the effect of Erdr1 as a TCR signaling modulator was not studied in peripheral T cells. In this report, it was determined whether Erdr1 affected TCR signaling strength in CD4 T cells. Results revealed that Erdr1 significantly enhanced the anti-TCR antibody-mediated activation and proliferation of T cells while failing to activate T cells in the absence of TCR stimulation. In addition, Erdr1 amplified Ca2+ influx and the phosphorylation of PLCγ1 in CD4 T cells with the TCR stimuli. Furthermore, NFAT1 translocation into nuclei in CD4 T cells was also significantly promoted by Erdr1 in the presence of TCR stimulation. Taken together, our results indicate that Erdr1 positively modulates TCR signaling strength via enhancing the PLCγ1/Ca2+/NFAT1 signal transduction pathway.

scholarly journals A Role for Thymic Stromal Lymphopoietin in CD4+ T Cell Development

2004 ◽  
Vol 200 (2) ◽  
pp. 159-168 ◽  
Author(s):  
Amin Al-Shami ◽  
Rosanne Spolski ◽  
John Kelly ◽  
Terry Fry ◽  
Pamela L. Schwartzberg ◽  
...  
Keyword(s):  
T Cells ◽  
Cd4 T Cells ◽  
Severe Combined Immunodeficiency ◽  
Thymic Stromal Lymphopoietin ◽  
Lymphoid Development ◽  
Peripheral T Cells ◽  
Single Positive ◽  
Lymphocyte Populations

Thymic stromal lymphopoietin (TSLP) signals via a receptor comprising the interleukin (IL)-7 receptor α chain and a distinctive subunit, TSLP receptor (TSLPR), which is most related to the common cytokine receptor γ chain, γc. We have generated TSLPR knockout (KO) mice and found that although these mice had normal lymphocyte numbers, γc/TSLPR double KO mice had a greater lymphoid defect than γc KO mice. This indicates that TSLP contributes to lymphoid development and accounts for some of the residual lymphoid development in γc KO mice and presumably in patients with X-linked severe combined immunodeficiency. Injection of TSLP into γc KO mice induced the expansion of T and B cells. Moreover, sublethally irradiated TSLPR KO mice showed weaker recovery of lymphocyte populations than wild-type (WT) littermates, even when neutralizing anti–IL-7 antibodies were injected. Interestingly, TSLP preferentially stimulated the proliferation and survival of CD4+ single positive thymocytes and peripheral T cells in vitro. Additionally, CD4+ T cells from TSLPR KO mice expanded less efficiently than WT CD4+ T cells in irradiated hosts, and TSLP preferentially expanded CD4+ T cells both in vitro and in vivo. Thus, as compared with other known cytokines, TSLP is distinctive in exhibiting a lineage preference for the expansion and survival of CD4+ T cells.

scholarly journals Development of Autologous, Oligoclonal, Poorly Functioning T Lymphocytes in a Patient With Autosomal Recessive Severe Combined Immunodeficiency Caused by Defects of the Jak3 Tyrosine Kinase

Blood ◽  
1998 ◽  
Vol 91 (3) ◽  
pp. 949-955 ◽  
Author(s):  
Duilio Brugnoni ◽  
Luigi D. Notarangelo ◽  
Alessandra Sottini ◽  
Paolo Airò ◽  
Marta Pennacchio ◽  
...  
Keyword(s):  
T Cells ◽  
T Lymphocytes ◽  
Tyrosine Kinase ◽  
Cd4 T Cells ◽  
Severe Combined Immunodeficiency ◽  
Combined Immunodeficiency ◽  
T Helper ◽  
T Helper 1 ◽  
In Vitro Susceptibility ◽  
And Function

Abstract Defects of the common gamma chain subunit of the cytokine receptors (γc) or of Jak3, a tyrosine kinase required for γc signal transduction, result in T−B+ severe combined immunodeficiency (SCID). However, atypical cases, characterized by progressive development of T lymphocytes, have been also reported. We describe a child with SCID caused by Jak3 gene defects, which strongly but not completely affect Jak3 protein expression and function, who developed a substantial number (>3,000/μL) of autologous CD3+CD4+ T cells. These cells showed a primed/activated phenotype (CD45R0+ Fas+HLA-DR+ CD62Llo), defective secretion of T-helper 1 and T-helper 2 cytokines, reduced proliferation to mitogens, and a high in vitro susceptibility to spontaneous (caused by downregulation of bcl-2 expression) as well as activation-induced cell death. A restricted T-cell receptor repertoire was observed, with oligoclonal expansion within each of the dominant segments. These features resemble those observed in γc-/y and in Jak3−/−mice, in which a population of activated, anergic T cells (predominantly CD4+) also develops with age. These results suggest that residual Jak3 expression and function or other Jak3-independent signals may also permit the generation of CD4+ T cells that undergo in vivo clonal expansion in humans; however, these mechanisms do not allow development of CD8+ T cells, nor do they fully restore the functional properties of CD4+ T lymphocytes.

scholarly journals CCL21 mediates CD4+ T-cell costimulation via a DOCK2/Rac-dependent pathway

Blood ◽  
2009 ◽  
Vol 114 (3) ◽  
pp. 580-588 ◽  
Author(s):  
Kathrin Gollmer ◽  
François Asperti-Boursin ◽  
Yoshihiko Tanaka ◽  
Klaus Okkenhaug ◽  
Bart Vanhaesebroeck ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
T Cell Activation ◽  
Cd4 T Cells ◽  
Cell Activation ◽  
Early Time ◽  
Cell Receptor ◽  
Tcr Signaling ◽  
Activation Markers

Abstract CD4+ T cells use the chemokine receptor CCR7 to home to and migrate within lymphoid tissue, where T-cell activation takes place. Using primary T-cell receptor (TCR)–transgenic (tg) CD4+ T cells, we explored the effect of CCR7 ligands, in particular CCL21, on T-cell activation. We found that the presence of CCL21 during early time points strongly increased in vitro T-cell proliferation after TCR stimulation, correlating with increased expression of early activation markers. CCL21 costimulation resulted in increased Ras- and Rac-GTP formation and enhanced phosphorylation of Akt, MEK, and ERK but not p38 or JNK. Kinase-dead PI3KδD910A/D910A or PI3Kγ-deficient TCR-tg CD4+ T cells showed similar responsiveness to CCL21 costimulation as control CD4+ T cells. Conversely, deficiency in the Rac guanine exchange factor DOCK2 significantly impaired CCL21-mediated costimulation in TCR-tg CD4+ T cells, concomitant with impaired Rac- but not Ras-GTP formation. Using lymph node slices for live monitoring of T-cell behavior and activation, we found that G protein-coupled receptor signaling was required for early CD69 expression but not for Ca2+ signaling. Our data suggest that the presence of CCL21 during early TCR signaling lowers the activation threshold through Ras- and Rac-dependent pathways leading to increased ERK phosphorylation.

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