scholarly journals Allelic Exclusion in pTα-deficient Mice: No Evidence for Cell Surface Expression of Two T Cell Receptor (TCR)-β Chains, but Less Efficient Inhibition of Endogeneous Vβ→ (D)Jβ Rearrangements in the Presence of a Functional TCR-β Transgene

1997 ◽  
Vol 186 (5) ◽  
pp. 767-775 ◽  
Author(s):  
Anna Krotkova ◽  
Harald von Boehmer ◽  
Hans Jörg Fehling

Although individual T lymphocytes have the potential to generate two distinct T cell receptor (TCR)-β chains, they usually express only one allele, a phenomenon termed allelic exclusion. Expression of a functional TCR-β chain during early T cell development leads to the formation of a pre-T cell receptor (pre-TCR) complex and, at the same developmental stage, arrest of further TCR-β rearrangements, suggesting a role of the pre-TCR in mediating allelic exclusion. To investigate the potential link between pre-TCR formation and inhibition of further TCR-β rearrangements, we have studied the efficiency of allelic exclusion in mice lacking the pre-TCR-α (pTα) chain, a core component of the pre-TCR. Staining of CD3+ thymocytes and lymph node cells with antibodies specific for Vβ6 or Vβ8 and a pool of antibodies specific for most other Vβ elements, did not reveal any violation of allelic exclusion at the level of cell surface expression. This was also true for pTα-deficient mice expressing a functionally rearranged TCR-β transgene. Interestingly, although the transgenic TCR-β chain significantly influenced thymocyte development even in the absence of pTα, it was not able to inhibit fully endogeneous TCR-β rearrangements either in total thymocytes or in sorted CD25+ pre-T cells of pTα−/− mice, clearly indicating an involvement of the pre-TCR in allelic exclusion.

1998 ◽  
Vol 187 (1) ◽  
pp. 105-116 ◽  
Author(s):  
Laurence Ardouin ◽  
Jamila Ismaili ◽  
Bernard Malissen ◽  
Marie Malissen

The pre–T cell receptor (TCR) associates with CD3-transducing subunits and triggers the selective expansion and maturation of T cell precursors expressing a TCR-β chain. Recent experiments in pre-Tα chain-deficient mice have suggested that the pre-TCR may not be required for signaling allelic exclusion at the TCR-β locus. Using CD3-ε– and CD3-ζ/η–deficient mice harboring a productively rearranged TCR-β transgene, we showed that the CD3-γδε and CD3-ζ/η modules, and by inference the pre-TCR/CD3 complex, are each essential for the establishment of allelic exclusion at the endogenous TCR-β locus. Furthermore, using mutant mice lacking both the CD3-ε and CD3-ζ/η genes, we established that the CD3 gene products are dispensable for the onset of V to (D)J recombination (V, variable; D, diversity; J, joining) at the TCR-β, TCR-γ, and TCR-δ loci. Thus, the CD3 components are differentially involved in the sequential events that make the TCR-β locus first accessible to, and later insulated from, the action of the V(D)J recombinase.


2001 ◽  
Vol 18 (1) ◽  
pp. 24-33 ◽  
Author(s):  
Jens Peter H. Lauritsen ◽  
Charlotte Menné ◽  
Jesper Kastrup ◽  
Jes Dietrich ◽  
Carsten Geisler

Nature ◽  
1988 ◽  
Vol 336 (6194) ◽  
pp. 76-79 ◽  
Author(s):  
Susan A. McCarthy ◽  
Ada M. Kruisbeek ◽  
Ingeborg K. Uppenkamp ◽  
Susan O. Sharrow ◽  
Alfred Singer

1996 ◽  
Vol 184 (5) ◽  
pp. 1833-1843 ◽  
Author(s):  
H Jacobs ◽  
J Iacomini ◽  
M van de Ven ◽  
S Tonegawa ◽  
A Berns

The T cell receptor beta (TCR beta) chain controls the developmental transition from CD4-CD8- to CD4+8+thymocytes. We show that the extracellular constant region and the transmembrane region, but not the variable domain or cytoplasmic tail of the TCR beta chain are required for this differentiation step. TCR beta mutant chains lacking the cytoplasmic tail can be found at the cell surface both in functional TCR/CD3 complexes and in a GPI-anchored monomeric form indicating that the cytoplasmic tail of the TCR beta chain functions as an ER retention signal. The concordance between cell surface expression of the mutant chains as TCR/CD3 complexes and their capacity to mediate thymocyte differentiation supports the CD3 mediated feedback model in which preTCR/CD3 complexes control the developmental transition from CD4-CD8- to CD4+CD8+thymocytes.


1993 ◽  
Vol 178 (6) ◽  
pp. 1867-1875 ◽  
Author(s):  
C N Levelt ◽  
R Carsetti ◽  
K Eichmann

Recent studies have shown that maturation of CD4-8- double negative (DN) thymocytes to the CD4+8+ double positive (DP) stage is dependent on expression of the T cell receptor (TCR)-beta polypeptide. The exact mechanism by which the TCR-beta chain regulates this maturation step remains unknown. Previous experiments had suggested that in the presence of some TCR+ thymocytes, additional DN thymocytes not expressing a TCR-beta chain may be recruited to mature to the DP stage. The recent demonstration of an immature TCR-beta-CD3 complex on early thymocytes lead to the alternative hypothesis that signal transduction through an immature TCR-CD3 complex may induce maturation to the DP stage. In the latter case, maturation to the DP stage would depend on the expression of TCR-beta-CD3 in the same cell. We examined these two hypotheses by studying the expression of the intra- and extracellular CD3 epsilon, CD3 zeta, and TCR-beta polypeptides in intrathymic subpopulations during embryogenesis. CD3 epsilon and CD3 zeta were expressed intracellularly 2 and 1 d, respectively, before intracellular expression of the TCR-beta chain, potentially allowing immediate surface expression of an immature TCR-beta-CD3 complex as soon as functional rearrangement of a TCR-beta gene locus has been accomplished. Calcium mobilization could be induced by stimulation with anti-CD3 epsilon mAb as soon as intracellular TCR-beta was detectable, suggesting that a functional TCR-beta-CD3 complex is indeed expressed on the surface of early thymocytes. From day 17 on, most cells were in the DP stage, and over 95% of the DP cells expressed on the TCR-beta chain intracellularly. At day 19 of gestation, extremely low concentrations of TCR-beta chain and CD3 epsilon were detectable on the cell surface of nearly all thymocytes previously thought to be TCR-CD3 negative. These findings strongly support the hypothesis that maturation to the DP stage depends on surface expression of and subsequent signal transduction through an immature TCR-beta-CD3 complex and suggest that maturation to the DP stage by recruitment, if it occurs at all, is of minor relevance.


1993 ◽  
Vol 177 (4) ◽  
pp. 1079-1092 ◽  
Author(s):  
H R Rodewald ◽  
K Awad ◽  
P Moingeon ◽  
L D'Adamio ◽  
D Rabinowitz ◽  
...  

We have recently identified a dominant wave of CD4-CD8- (double-negative [DN]) thymocytes in early murine fetal development that express low affinity Fc gamma receptors (Fc gamma RII/III) and contain precursors for Ti alpha/beta lineage T cells. Here we show that Fc gamma RII/III is expressed in very immature CD4low single-positive (SP) thymocytes and that Fc gamma RII/III expression is downregulated within the DN subpopulation and before the CD3-CD8low SP stage in T cell receptor (TCR)-alpha/beta lineage-committed thymocytes. DN Fc gamma RII/III+ thymocytes also contain a small fraction of TCR-gamma/delta lineage cells in addition to TCR-alpha/beta progenitors. Fetal day 15.5 DN TCR-alpha/beta lineage progenitors can be subdivided into three major subpopulations as characterized by cell surface expression of Fc gamma RII/III vs. CD2 (Fc gamma RII/III+CD2-, Fc gamma RII/III+CD2+, Fc gamma RII/III-CD2+). Phenotypic analysis during fetal development as well as adoptive transfer of isolated fetal thymocyte subpopulations derived from C57B1/6 (Ly5.1) mice into normal, nonirradiated Ly5.2 congenic recipient mice identifies one early differentiation sequence (Fc gamma RII/III+CD2(-)-->Fc gamma RII/III+CD2(+)-->Fc gamma RII/III-CD2+) that precedes the entry of DN thymocytes into the CD4+CD8+ double-positive (DP) TCRlow/- stage. Unseparated day 15.5 fetal thymocytes develop into DP thymocytes within 2.5 d and remain at the DP stage for > 48 h before being selected into either CD4+ or CD8+ SP thymocytes. In contrast, Fc gamma RII/III+CD2- DN thymocytes follow this same developmental pathway but are delayed by approximately 24 h before entering the DP compartment, while Fc gamma RII/III-CD2+ display accelerated development by approximately 24 h compared with total day 15.5 thymocytes. Fc gamma RII/III-CD2+ are also more developmentally advanced than Fc gamma RII/III+CD2- fetal thymocytes with respect to their TCR beta chain V(D)J rearrangement. At day 15.5 in gestation, beta chain V(D)J rearrangement is mostly, if not entirely, restricted to the Fc gamma RII/III-CD2+ subset of DN fetal thymocytes. Consistent with this analysis in fetal thymocytes, > 90% of adult thymocytes derived from mice carrying a disrupting mutation at the recombination-activating gene 2 locus (RAG-2-/-) on both alleles are developmentally arrested at the DN CD2- stage. In addition, there is a fivefold increase in the relative percentage of thymocytes expressing Fc gamma RII/III in TCR and immunoglobulin gene rearrangement-incompetent homozygous RAG-2-/- mice (15% Fc gamma RII/III+) versus rearrangement-competent heterozygous RAG-2+/- mice (< 3% Fc gamma RII/III+). Thus, Fc gamma RII/III expression defines an early DN stage preceding V beta(D beta)I beta rearrangement, which in turn is followed by surface expression of CD2. Loss of Fc gamma RII/III and acquisition of CD2 expression characterize a late DN stage immediately before the conversion into DP thymocytes.


1995 ◽  
Vol 24 (6) ◽  
pp. 927-946 ◽  
Author(s):  
O. Mazda ◽  
Y. Aiba ◽  
N. Hattori ◽  
M. Li ◽  
S. Fujimoto ◽  
...  

2006 ◽  
Vol 203 (6) ◽  
pp. 1543-1550 ◽  
Author(s):  
Iannis Aifantis ◽  
Craig H. Bassing ◽  
Annette I. Garbe ◽  
Katie Sawai ◽  
Frederick W. Alt ◽  
...  

It is well established that the pre–T cell receptor for antigen (TCR) is responsible for efficient expansion and differentiation of thymocytes with productive TCRβ rearrangements. However, Ptcra- as well as Tcra-targeting experiments have suggested that the early expression of Tcra in CD4−CD8− cells can partially rescue the development of αβ CD4+CD8+ cells in Ptcra-deficient mice. In this study, we show that the TCR Eδ but not Eα enhancer function is required for the cell surface expression of αβTCR on immature CD4−CD8− T cell precursors, which play a crucial role in promoting αβ T cell development in the absence of pre-TCR. Thus, αβTCR expression by CD4−CD8− thymocytes not only represents a transgenic artifact but occurs under physiological conditions.


Blood ◽  
2008 ◽  
Vol 112 (13) ◽  
pp. 5103-5110 ◽  
Author(s):  
Jennifer M. L. Tjon ◽  
Wieke H. M. Verbeek ◽  
Yvonne M. C. Kooy-Winkelaar ◽  
Binh H. Nguyen ◽  
Arno R. van der Slik ◽  
...  

Abstract Enteropathy-associated T-cell lymphoma, an often fatal complication of celiac disease, can result from expansion of aberrant intraepithelial lymphocytes in refractory celiac disease type II (RCD II). Aberrant intraepithelial lymphocytes and lymphoma cells are intracellularly CD3ϵ+ but lack expression of the T-cell receptor (TCR)–CD3 complex on the cell surface. It is unknown what causes the loss of TCR-CD3 expression. We report the isolation of a cell line from an RCD II patient with the characteristic phenotype of enteropathy-associated T-cell lymphoma. We demonstrate that in this cell line the TCR-α and -β chains as well as the CD3γ, CD3δ, CD3ϵ, and ζ-chains are present intracellularly and that assembly of the CD3γϵ, CD3δϵ, and ζζ-dimers is normal. However, dimerization of the TCR chains and proper assembly of the TCR-CD3 complex are defective. On introduction of exogenous TCR-β chains, but not of TCR-α chains, assembly and functional cell surface expression of the TCR-CD3 complex were restored. Defective synthesis of both TCR chains was found to underlie loss of TCR expression in similar cell lines isolated from 2 additional patients. (Pre)malignant transformation in RCD II thus correlates with defective synthesis or defective association of the TCR chains, resulting in loss of surface TCR-CD3 expression.


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