scholarly journals Distinctive selection mechanisms govern the T cell receptor repertoire of peripheral CD4-CD8- alpha/beta T cells.

1992 ◽  
Vol 176 (3) ◽  
pp. 699-706 ◽  
Author(s):  
L Huang ◽  
I N Crispe

The T cell receptor (TCR) repertoire of CD4+ and CD8+ alpha/beta T cells is heavily influenced by positive and negative selection events that occur during T cell development in the thymus. The coreceptors CD4 and CD8 appear to be essential for this selection to occur. To gain insight into whether T cells that express TCR alpha/beta but lack either coreceptor (CD4- CD8- TCR alpha/beta or alpha/beta double-negative [DN] cells) are also subject to positive and negative selection, and whether selection can occur in the absence of coreceptors, we have performed an extensive immunogenetic analysis of the TCR V beta repertoire of alpha/beta DN cells in lymph nodes of normal mice. Our results show that alpha/beta DN cells appear to be unaffected by clonal deletion of V beta 5 and V beta 11 in I-E-expressing mice, and do not undergo deletion of V beta 6- and V beta 8.1-expressing T cells in Mls-1a-positive mice. They are also unaffected by positive selection of V beta 17a+ T cells in the context of I-Aq. The results suggest that most selection events require the participation of CD4 and CD8, while alpha/beta DN cells are unselected. This argues that most alpha/beta DN cells probably have never expressed CD4 or CD8. However, a unique form of repertoire selection occurs: enrichment of V beta 17a+ alpha/beta DN cells in I-E+ mice. This could be an instance of coreceptor-independent selection.

1989 ◽  
Vol 19 (11) ◽  
pp. 2175-2177 ◽  
Author(s):  
Eric J. Jenkinson ◽  
Rosetta Kingston ◽  
Christopher A. Smith ◽  
Gwynn T. Williams ◽  
John J. T. Owen

1994 ◽  
Vol 180 (5) ◽  
pp. 1685-1691 ◽  
Author(s):  
F Davodeau ◽  
M A Peyrat ◽  
J Gaschet ◽  
M M Hallet ◽  
F Triebel ◽  
...  

Structural diversity of lymphocyte antigen receptors (the immunoglobulin [Ig] of B cells and the alpha/beta or gamma/delta T cell receptor [TCR] of T cells) is generated through somatic rearrangements of V, D, and J gene segments. Classically, these recombination events involve gene segments from the same Ig or TCR locus. However, occurrence of "trans" rearrangements between distinct loci has also been described, although in no instances was the surface expression of the corresponding protein under normal physiological conditions demonstrated. Here we show that hybrid TCR genes generated by trans rearrangement between V gamma and (D) J beta elements are translated into functional antigen receptor chains, paired with TCR alpha chains. Like classical alpha/beta T cells, cells expressing these hybrid TCR chains express either CD4 or CD8 coreceptors and are frequently alloreactive. These results have several implications in terms of T cell repertoire selection and relationships between TCR structure and specificity. First, they suggest that TCR alloreactivity is determined by the repertoire selection processes operating during lymphocyte development rather than by structural features specific to V alpha V beta regions. Second, they suggest the existence of close structural relationships between gamma/delta and alpha/beta TCR and more particularly, between V gamma and V beta regions. Finally, since a significant fraction of PBL (at least 1/10(4)) expressed hybrid TCR chains on their surface, these observations indicate that trans rearrangements significantly contribute to the combinatorial diversification of the peripheral immune repertoire.


1997 ◽  
Vol 186 (11) ◽  
pp. 1911-1922 ◽  
Author(s):  
Jennifer A. Punt ◽  
Wendy Havran ◽  
Ryo Abe ◽  
Apurva Sarin ◽  
Alfred Singer

Negative selection is the process by which the developing lymphocyte receptor repertoire rids itself of autoreactive specificities. One mechanism of negative selection in developing T cells is the induction of apoptosis in immature CD4+CD8+ (DP) thymocytes, referred to as clonal deletion. Clonal deletion is necessarily T cell receptor (TCR) specific, but TCR signals alone are not lethal to purified DP thymocytes. Here, we identify two distinct mechanisms by which TCR-specific death of DP thymocytes can be induced. One mechanism requires simultaneous TCR and costimulatory signals initiated by CD28. The other mechanism is initiated by TCR signals in the absence of simultaneous costimulatory signals and is mediated by subsequent interaction with antigen-presenting cells. We propose that these mechanisms represent two distinct clonal deletion strategies that are differentially implemented during development depending on whether immature thymocytes encounter antigen in the thymic cortex or thymic medulla.


1992 ◽  
Vol 176 (1) ◽  
pp. 187-199 ◽  
Author(s):  
P Poussier ◽  
P Edouard ◽  
C Lee ◽  
M Binnie ◽  
M Julius

We demonstrate that mouse intestinal intraepithelial lymphocytes (IEL) can be divided into subsets based on the differential expression of functional T cell receptor alpha/beta (TCR-alpha/beta) signaling complexes. Two subsets, CD4+ 8 alpha + beta - and CD8 alpha + beta -, are refractory to stimulation with anti-TCR-alpha/beta and contain high frequencies of potentially self-reactive cells. In contrast, the CD4+ and CD8 alpha + beta + IEL subsets are responsive to anti-TCR-alpha/beta and depleted of potentially self-reactive cells. The analysis of fetal liver radiation chimeras using adult thymectomized recipients demonstrates that the four TCR-alpha/beta + IEL subsets are generated in normal numbers in the absence of the thymus. Moreover, expression of the major histocompatibility complex class II-encoded I-E molecule and Mls1a in the gut of the athymic host results in the negative selection of potentially self-reactive T cells expressing V beta 11 and V beta 6, respectively, from those IEL subsets that express functional TCR-alpha/beta signaling complexes. Neither the spleen nor the Peyer's patches of athymic recipients contain T cells of donor origin. In contrast, normal numbers of phenotypically and functionally mature CD4+ and CD8 alpha + beta + T cells of donor origin are found in the lamina propria of chimeric animals. The phenotypic analysis of lymphocytes obtained from Ly5 congenic parabionts reveals that peripheral T cells migrate rapidly to the Peyer's patches and lamina propria, but not to the intestinal epithelium. Taken together, these results demonstrate that the intestinal epithelium is a thymus-independent site of T lymphopoiesis, where selection of the T cell repertoire involves the deletion of potentially self-reactive cells in situ. Moreover, the appearance of donor-derived, phenotypically mature T cells, exclusively in the lamina propria of athymic radiation chimeras, suggests that mature IEL expressing functional TCR-alpha/beta migrate to this site.


Blood ◽  
1996 ◽  
Vol 88 (12) ◽  
pp. 4601-4610 ◽  
Author(s):  
YL Colson ◽  
J Lange ◽  
K Fowler ◽  
ST Ildstad

Bone marrow (BM) chimeras prepared by complete recipient ablation (A-->B) exhibit donor-specific tolerance, yet survival is often limited by graft-versus-host disease (GVHD). Negative selection of potentially donor-reactive T cells, as assessed by relative T-cell receptor (TCR)- Vbeta expression, is dependent on donor BM-derived deleting ligands. Mixed chimerism and tolerance for both donor and host antigens can be achieved using partial recipient myeloablation with 500 cGy total-body irradiation (TBI) before transplantation followed by cyclophosphamide (CyP) on day +2. To examine the influence of residual host elements on negative selection, the peripheral TCR-Vbeta repertoire was analyzed in partially ablated C57BL/10SnJ (B10) recipients reconstituted with BM from major histocompatibility complex (MHC)-disparate B10.BR/SgSnJ or MHC, Hh-1 and Mls-disparate BALB/cByJ donors, which delete Vbeta5+ and 11+ or Vbeta3+, 5+, and 11+ TCR subsets, respectively. As in myeloblated recipients, donor-reactive subfamilies were deleted in B10.BR-->B10 and BALB/c-->B10 chimeras, suggesting that donor I-E and minor lymphocyte-stimulating (Mls) antigens contribute to the deleting ligands in the nonmyeloablated host. In striking contrast to completely ablated B10-->B10.BR chimeras, partially ablated recipients showed intramedullary I-E expression in the thymus and deleted host-reactive Vbeta5+ and Vbeta11+ subfamilies. These data demonstrate that efficient clonal deletion occurs after partial myeloablation and that both donor and host ligands contribute to TCR repertoire selection.


1992 ◽  
Vol 175 (4) ◽  
pp. 907-915 ◽  
Author(s):  
S Yoshino ◽  
L G Cleland

The effects of treatment with a monoclonal antibody (R73 mAb) against T cell receptor alpha/beta (TCR-alpha/beta) on both established adjuvant arthritis (EAA) and established collagen-induced arthritis (ECIA) in rats have been investigated. Rats were treated with R73 mAb when arthritis reached a peak. Treatment with the anti-TCR-alpha/beta mAb markedly suppressed EAA, whereas ECIA was not affected by the mAb treatment. Histologically, R73 mAb-treated rats with EAA showed mild hyperplasia of synovial tissues, sparse infiltration of inflammatory cells, and minimal erosion of cartilage, whereas arthritic rats treated with PBS and an irrelevant control mAb against Giardia had marked hyperplasia of synovium with pannus, massive inflammatory cell infiltrate, and severe destruction of cartilage and subchondral bone. R73 mAb-treated rats with ECIA exhibited pronounced formation of pannus containing many inflammatory cells and marked cartilage and subchondral damage similar to those in arthritic rats that received the control treatments. Treatment with R73 mAb depleted markedly alpha/beta+ T cells in both peripheral blood and synovial tissues of rats with EAA and ECIA. R73 mAb treatment was associated with marked reduction in arthritogen-specific delayed-type hypersensitivity responses in both EAA and ECIA. The titers of antibodies against type II collagen produced in rats with ECIA were not affected by the mAb. Thus, alpha/beta+ T cells appear to have a central role in EAA, but not in chronic ECIA.


1991 ◽  
Vol 174 (2) ◽  
pp. 417-424 ◽  
Author(s):  
T Abo ◽  
T Ohteki ◽  
S Seki ◽  
N Koyamada ◽  
Y Yoshikai ◽  
...  

We demonstrated in the present study that with bacterial stimulation, an increased number of alpha/beta T cells proliferated in the liver of mice and that even T cells bearing self-reactive T cell receptor (TCR) (or forbidden T cell clones), as estimated by anti-V beta monoclonal antibodies in conjunction with immunofluorescence tests, appeared in the liver and, to some extent, in the periphery. The majority (greater than 80%) of forbidden clones induced had double-negative CD4-8-phenotype. In a syngeneic mixed lymphocyte reaction, these T cells appear to be self-reactive. Such forbidden clones and normal T cells in the liver showed a two-peak pattern of TCR expression, which consisted of alpha/beta TCR dull and bright positive cells, as seen in the thymus. A systematic analysis of TCR staining patterns in the various organs was then carried out. T cells from not only the thymus but also the liver had the two-peak pattern of alpha/beta TCR, whereas all of the other peripheral lymphoid organs had a single-peak pattern of TCR. However, T cells in the liver were not comprised of double-positive CD4+8+ cells, which predominantly reside in the thymus. The present results therefore suggest that T cell proliferation in the liver might reflect a major extrathymic pathway for T cell differentiation and that this hepatic pathway has the ability to produce T cells bearing self-reactive TCR under bacterial stimulation, probably due to the lack of a double-positive stage for negative selection.


2020 ◽  
Vol 14 (Supplement_1) ◽  
pp. S176-S177
Author(s):  
A Gamliel ◽  
L Werner ◽  
N Salamon ◽  
M Pinsker ◽  
B Weiss ◽  
...  

Abstract Background Memory T cells play an important role in mediating inflammatory responses in IBD. The integrin a4b7 is highly expressed on activated T cells, and is thought to direct homing of lymphocytes to the intestine, following its binding to MADCAM-1 expressed exclusively on intestinal endothelial cells. Since UC is characterised by oligoclonal expansion of specific T-cell clonotypes, we hypothesised that circulating memory T cells with gut-homing potential would exhibit unique T-cell receptor repertoire features. Methods Peripheral blood mononuclear cells were collected from 5 control subjects and 6 pediatric patients with active UC. Following CD3 MACS sorting cells were FACS sorted into a4b7 positive and a4b7 negative CD3+CD45RO+ memory T cells. DNA was Isolated from each subset and subjected to next-generation sequencing of the TCRB. This high-throughput platform employs massive parallel sequencing to process millions of rearranged T-cell receptor (TCR) products simultaneously, and permits an in-depth analysis of individual TCRs at the nucleotide level. Comparisons of different indices of diversity, CDR3 length and clonal biochemical characteristics were performed between a4b7 positive and a4b7 negative populations for each subject, and between controls and UC patients. Results PBMCs were isolated from active UC patients during endoscopic assessment. Four patients had a Mayo endoscopic score of 2, and two patients had a score of 1. Only one patient was treated with an immunosuppressive medication (azathioprine), and five out of six patients were treated with 5ASAs. Percentages of memory T cells (43.8 ± 12.3% vs. 32.2 ± 13.1%, p = 0.17) and a4b7 positive T cells (33.6 ± 15.7% vs. 36.0 ± 17.6%, p = 0.81) were comparable between controls and UC patients. Interestingly, a4b7 positive memory T cells displayed a polyclonal distribution, in both control subjects and in UC patients, without expansion of specific clones. Different indices of diversity, including shanon’s H, clonality index and entropy, were similar among controls and patients, both for a4b7 positive and a4b7 negative populations. Finally, clonal overlap between a4b7 positive and a4b7 negative memory T cells, for each subject was high, ranging between 30–50% for controls and 27–48% for UC patients. Conclusion a4b7 expressing memory T cells exhibited a polyclonal repertoire in both control subjects and patients with active UC, with high rates of overlap with a4b7 negative memory T cells. Our study, along with additional recent reports, challenge the dogma of the importance of a4b7 expression for T-cell migration to the gut, and may suggest that vedolizumab’s suppresses intestinal inflammation by blocking the trafficking of innate immune subsets.


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