scholarly journals Insights into Thymus Development and Viral Thymic Infections

Viruses ◽  
2019 ◽  
Vol 11 (9) ◽  
pp. 836 ◽  
Author(s):  
Francesco Albano ◽  
Eleonora Vecchio ◽  
Maurizio Renna ◽  
Enrico Iaccino ◽  
Selena Mimmi ◽  
...  

T-cell development in the thymus is a complex and highly regulated process, involving a wide variety of cells and molecules which orchestrate thymocyte maturation into either CD4+ or CD8+ single-positive (SP) T cells. Here, we briefly review the process regulating T-cell differentiation, which includes the latest advances in this field. In particular, we highlight how, starting from a pool of hematopoietic stem cells in the bone marrow, the sequential action of transcriptional factors and cytokines dictates the proliferation, restriction of lineage potential, T-cell antigen receptors (TCR) gene rearrangements, and selection events on the T-cell progenitors, ultimately leading to the generation of mature T cells. Moreover, this review discusses paradigmatic examples of viral infections affecting the thymus that, by inducing functional changes within this lymphoid gland, consequently influence the behavior of peripheral mature T-lymphocytes.

Blood ◽  
2005 ◽  
Vol 105 (4) ◽  
pp. 1431-1439 ◽  
Author(s):  
Ross N. La Motte-Mohs ◽  
Elaine Herer ◽  
Juan Carlos Zúñiga-Pflücker

AbstractThe Notch signaling pathway plays a key role at several stages of T-lymphocyte differentiation. However, it remained unclear whether signals induced by the Notch ligand Delta-like 1 could support full T-cell differentiation from a defined source of human hematopoietic stem cells (HSCs) in vitro. Here, we show that human cord blood–derived HSCs cultured on Delta-like 1–expressing OP9 stromal cells undergo efficient T-cell lineage commitment and sustained T-cell differentiation. A normal stage-specific program of T-cell development was observed, including the generation of CD4 and CD8 αβ–T-cell receptor (TCR)–bearing cells. Induction of T-cell differentiation was dependent on the expression of Delta-like 1 by the OP9 cells. Stimulation of the in vitro–differentiated T cells by TCR engagement induced the expression of T-cell activation markers and costimulatory receptors. These results establish an efficient in vitro coculture system for the generation of T cells from human HSCs, providing a new avenue for the study of early T-cell differentiation and function.


2018 ◽  
Vol 46 (4) ◽  
pp. 441-449
Author(s):  
Sowmya Angusamy ◽  
Tamer Mansour ◽  
Mohammed Abdulmageed ◽  
Rachel Han ◽  
Brian C. Schutte ◽  
...  

Abstract Background: The adaptive immune system of neonates is relatively underdeveloped. The thymus is an essential organ for adaptive T cell development and might be affected during the natural course of oxygen induced lung injury. The effect of prolonged hyperoxia on the thymus, thymocyte and T cell development, and its proliferation has not been studied extensively. Methods: Neonatal mice were exposed to 85% oxygen (hyperoxia) or room air (normoxia) up to 28 days. Flow cytometry using surface markers were used to assay for thymocyte development and proliferation. Results: Mice exposed to prolonged hyperoxia had evidence of lung injury associated alveolar simplification, a significantly lower mean weight, smaller thymic size, lower mean thymocyte count and higher percentage of apoptotic thymocytes. T cells subpopulation in the thymus showed a significant reduction in the count and proliferation of double positive and double negative T cells. There was a significant reduction in the count and proliferation of single positive CD4+ and CD8+ T cells. Conclusions: Prolonged hyperoxia in neonatal mice adversely affected thymic size, thymocyte count and altered the distribution of T cells sub-populations. These results are consistent with the hypothesis that prolonged hyperoxia causes defective development of T cells in the thymus.


2008 ◽  
Vol 105 (46) ◽  
pp. 17919-17924 ◽  
Author(s):  
Julia Raberger ◽  
Alexandra Schebesta ◽  
Shinya Sakaguchi ◽  
Nicole Boucheron ◽  
K. Emelie M. Blomberg ◽  
...  

Transcriptional pathways controlling the development of CD44hi memory phenotype (MP) T cells with “innate-like” functions are not well understood. Here we show that the BTB (bric-a-brac, tramtrack, broad complex) domain-containing protein promyelocytic leukemia zinc finger (PLZF) is expressed in CD44hi, but not in CD44lo, CD4+ T cells. Transgenic expression of PLZF during T cell development and in CD4+ and CD8+ T cells induced a T cell intrinsic program leading to an increase in peripheral CD44hi MP CD4+ and CD8+ T cells and a corresponding decrease of naïve CD44lo T cells. The MP CD4+ and CD8+ T cells produced IFNγ upon PMA/ionomycin stimulation, thus showing innate-like function. Changes in the naïve versus memory-like subset distribution were already evident in single-positive thymocytes, indicating PLZF-induced T cell developmental alterations. In addition, CD1d-restricted natural killer T cells in PLZF transgenic mice showed impaired development and were severely reduced in the periphery. Finally, after anti-CD3/CD28 stimulation, CD4+ transgenic T cells showed reduced IL-2 and IFNγ production but increased IL-4 secretion as a result of enhanced IL-4 production of the CD44hiCD62L+ subset. Our data indicate that PLZF is a novel regulator of the development of CD44hi MP T cells with a characteristic partial innate-like phenotype.


Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 3266-3266
Author(s):  
Pablo Laje ◽  
William H. Peranteau ◽  
Masayuki Endo ◽  
Philip W. Zoltick ◽  
Alan W. Flake

Abstract The developing fetal immune system provides a unique opportunity to manipulate normal immunologic development for therapeutic prenatal and anticipated postnatal interventions. In previous studies we have shown that allogeneic in utero hematopoietic cell transplantation (IUHCT) results in donor specific tolerance that can subsequently facilitate non-myeloablative postnatal cellular or organ transplants. It follows that in utero injection of transduced hematopoietic stem cells (HSC) could potentially induce tolerance to a transgene encoded protein. We hypothesized that expression of a transduced antigenic protein by HSC and their progeny would alter thymic T cell development resulting in deletion of antigen specific T-cells. To test this hypothesis, we used the mammary tumor virus (MTV) superantigen system to evaluate the effect of IUHCT of transduced HSC on T cell development. In this system, expression of different MTV oncogenes by different I-E+ strains of mice results in deletion of T cells expressing the relevant Vβ T cell receptor. Specifically, mice which are Mtv7+ delete T cells expressing the Vβ6 T-cell receptor. In this study, CD150+CD48− enriched Balb/c (I-E+ Mtv7−) HSC were transduced with an HIV-based lentivirus expressing MTV7 under an MND promoter. 1.5E+05 transduced cells were injected intravascularly via the vitelline vein into E14 Balb/c fetuses. Non-injected age matched naive Balb/c mice served as the control group. The peripheral blood (PB) and thymuses of injected fetuses and control mice were harvested at day of life (DOL) 10, 20 and 60 and analyzed by flow cytometry for T lymphocyte Vβ6 expression. Additionally, the T cell composition of the thymus was assessed at DOL10 for CD4 and CD8 single positive (SP) and CD4/CD8 double positive (DP) cells. Thymic flow cytometric analysis at DOL10 revealed that greater than 98% of the T cells were CD4CD8 DP, a stage that has not yet undergone negative selection. No significant difference was noted in the percentage of thymic Vβ6+ DP T-cells at this time point or at DOL20 and DOL60. In contrast, there was a significant decrease in the percentage of Vβ6+ peripheral blood SP cells in those mice injected with MTV7 transduced HSC relative to control mice at DOL10, DOL20 and DOL60 (p<0.05) (Fig 1). The current study supports the ability of enriched transduced HSC to induce deletion of transgene specific T cells after IUHCT. In the future, this strategy may be useful to promote tolerance for pre or postnatal cellular or gene therapy. Figure Figure


Blood ◽  
2012 ◽  
Vol 120 (4) ◽  
pp. 789-799 ◽  
Author(s):  
Takeshi Isoda ◽  
Masatoshi Takagi ◽  
Jinhua Piao ◽  
Shun Nakagama ◽  
Masaki Sato ◽  
...  

Immune defect in ataxia telangiectasia patients has been attributed to either the failure of V(D)J recombination or class-switch recombination, and the chromosomal translocation in their lymphoma often involves the TCR gene. The ATM-deficient mouse exhibits fewer CD4 and CD8 single-positive T cells because of a failure to develop from the CD4+CD8+ double-positive phase to the single-positive phase. Although the occurrence of chromosome 14 translocations involving TCR-δ gene in ATM-deficient lymphomas suggests that these are early events in T-cell development, a thorough analysis focusing on early T-cell development has never been performed. Here we demonstrate that ATM-deficient mouse thymocytes are perturbed in passing through the β- or γδ-selection checkpoint, leading in part to the developmental failure of T cells. Detailed karyotype analysis using the in vitro thymocyte development system revealed that RAG-mediated TCR-α/δ locus breaks occur and are left unrepaired during the troublesome β- or γδ-selection checkpoints. By getting through these selection checkpoints, some of the clones with random or nonrandom chromosomal translocations involving TCR-α/δ locus are selected and accumulate. Thus, our study visualized the first step of multistep evolutions toward lymphomagenesis in ATM-deficient thymocytes associated with T-lymphopenia and immunodeficiency.


2020 ◽  
Author(s):  
Emilie Coppin ◽  
Bala Sai Sundarasetty ◽  
Susann Rahmig ◽  
Jonas Blume ◽  
Nikita A. Verheyden ◽  
...  

AbstractHumanized mouse models have become increasingly valuable tools to study human hematopoiesis and infectious diseases. However, human T cell differentiation remains inefficient. We generated mice expressing human interleukin (IL-7), a critical growth and survival factor for T cells, under the control of murine IL-7 regulatory elements. After transfer of human cord blood-derived hematopoietic stem and progenitor cells, transgenic mice on the NSGW41 background, termed NSGW41hIL7, showed elevated and prolonged human cellularity in the thymus while maintaining physiological ratios of thymocyte subsets. As a consequence, numbers of functional human T cells in the periphery were increased without evidence for pathological lymphoproliferation or aberrant expansion of effector or memory-like T cells. We conclude that the novel NSGW41hIL7 strain represents an optimized mouse model for humanization to better understand human T cell differentiation in vivo and to generate a human immune system with a better approximation of human lymphocyte ratios.


2018 ◽  
Author(s):  
Linda V Sinclair ◽  
Andrew JM Howden ◽  
Alejandro J Brenes-Murillo ◽  
Laura Spinelli ◽  
Jens L Hukelmann ◽  
...  

Immune activated T lymphocytes modulate the activity of key metabolic pathways to support the transcriptional reprograming and reshaping of cell proteomes that permits effector T cell differentiation. The present study uses high resolution mass spectrometry and metabolic labelling to explore how T cells control the methionine cycle to produce methyl donors for protein and nucleotide methylations. We show that antigen receptor engagement controls flux through the methionine cycle and also controls RNA and histone methylations. We establish that the main rate limiting step for the methionine cycle is control of methionine transporter expression by antigen receptors. Only T cells that respond to antigen to upregulate and sustain methionine transport are supplied with the methyl donors that permit the dynamic nucleotide methylations and epigenetic reprogramming that drives T cell differentiation.


Blood ◽  
1996 ◽  
Vol 87 (10) ◽  
pp. 4040-4048 ◽  
Author(s):  
M Rosenzweig ◽  
DF Marks ◽  
H Zhu ◽  
D Hempel ◽  
KG Mansfield ◽  
...  

Differentiation of hematopoietic progenitor cells into T lymphocytes generally occurs in the unique environment of the thymus, a feature that has hindered efforts to model this process in the laboratory. We now report that thymic stromal cultures from rhesus macaques can support T-cell differentiation of human or rhesus CD34+ progenitor cells. Culture of rhesus or human CD34+ bone marrow-derived cells depleted of CD34+ lymphocytes on rhesus thymic stromal monolayers yielded CD3+CD4+CD8+, CD3+CD4+CD8-, and CD3+CD4-CD8+ cells after 10 to 14 days. In addition to classical T lymphocytes, a discrete population of CD3+CD8loCD16+CD56+ cells was detected after 14 days in cultures inoculated with rhesus CD34+ cells. CD3+ T cells arising from these cultures were not derived from contaminating T cells present in the CD34+ cells used to inoculate thymic stromal monolayers or from the thymic monolayers, as shown by labeling of cells with the lipophilic membrane dye PKH26. Expression of the recombinase activation gene RAG- 2, which is selectively expressed in developing lymphocytes, was detectable in thymic cultures inoculated with CD34+ cells but not in CD34+ cells before thymic culture or in thymic stromal monolayers alone. Reverse transcriptase-polymerase chain reaction analysis of T cells derived from thymic stromal cultures of rhesus and human CD34+ cells showed a polyclonal T-cell receptor repertoire. T-cell progeny derived from rhesus CD34+ cells cultured on thymic stroma supported vigorous simian immunodeficiency virus replication in the absence of exogenous mitogenic stimuli. Rhesus thymic stromal cultures provide a convenient means to analyze T-cell differentiation in vitro and may be useful as a model of hematopoietic stem cell therapy for diseases of T cells, including acquired immunodeficiency syndrome.


2001 ◽  
Vol 194 (1) ◽  
pp. 99-106 ◽  
Author(s):  
David Allman ◽  
Fredrick G. Karnell ◽  
Jennifer A. Punt ◽  
Sonia Bakkour ◽  
Lanwei Xu ◽  
...  

Notch1 signaling is required for T cell development. We have previously demonstrated that expression of a dominant active Notch1 (ICN1) transgene in hematopoietic stem cells (HSCs) leads to thymic-independent development of CD4+CD8+ double-positive (DP) T cells in the bone marrow (BM). To understand the function of Notch1 in early stages of T cell development, we assessed the ability of ICN1 to induce extrathymic T lineage commitment in BM progenitors from mice that varied in their capacity to form a functional pre-T cell receptor (TCR). Whereas mice repopulated with ICN1 transduced HSCs from either recombinase deficient (Rag-2−/−) or Src homology 2 domain–containing leukocyte protein of 76 kD (SLP-76)−/− mice failed to develop DP BM cells, recipients of ICN1-transduced Rag-2−/− progenitors contained two novel BM cell populations indicative of pre-DP T cell development. These novel BM populations are characterized by their expression of CD3ε and pre-Tα mRNA and the surface proteins CD44 and CD25. In contrast, complementation of Rag-2−/− mice with a TCRβ transgene restored ICN1-induced DP development in the BM within 3 wk after BM transfer (BMT). At later time points, this population selectively and consistently gave rise to T cell leukemia. These findings demonstrate that Notch signaling directs T lineage commitment from multipotent progenitor cells; however, both expansion and leukemic transformation of this population are dependent on T cell–specific signals associated with development of DP thymocytes.


Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 124-124
Author(s):  
Ivan Maillard ◽  
Laleh Talebian ◽  
Zhe Li ◽  
Yalin Guo ◽  
Daisuke Sugiyama ◽  
...  

Abstract The family of core binding factors includes the DNA-binding subunits Runx1-3 and the common non-DNA binding partner CBFβ. Runx1 and CBFβ are essential for the emergence of hematopoietic stem cells during fetal development, but not for stem cell maintenance during later ontogeny. Runx1 is also required for megakaryocyte differentiation, B cell development, and for the DN2 to DN3 transition in thymocyte development. Runx2/CBFβ are critical for normal osteogenesis, and Runx3 for CD4 silencing in CD8+ T cells, but their contribution to other steps of hematopoietic development is unknown. To examine the collective role of core binding factors in hematopoiesis, we generated a hypomorphic Cbfb allele (Cbfbrss). CBFβ protein levels were reduced by approximately 2–3 fold in fetuses homozygous for the Cbfbrss allele (Cbfbrss/rss), and 3–4 fold in fetuses carrying one hypomorphic and one knockout allele (Cbfbrss/−). Cbfbrss/rss and Cbfbrss/− fetuses had normal erythroid and B cell development, and relatively mild abnormalities in megakaryocyte and granulocyte differentiation. In contrast, T cell development was very sensitive to an incremental reduction of CBFβ levels: mature thymocytes were decreased in Cbfbrss/rss fetuses, and virtually absent in Cbfbrss/−fetuses. We next assessed the development of Cbfbrss/rss and Cbfbrss/− fetal liver progenitors after transplantation to irradiated adult recipients, in competition with wild-type (wt) bone marrow cells. Wt, Cbfbrss/rss and Cbfbrss/− fetal progenitors replenished the erythroid, myeloid and B cell compartments equally well. The overall development of Cbfbrss/rss T cells was preserved, although CD4 expression was derepressed in double negative thymocytes. In Cbfbrss/− chimeras, mature thymocytes were entirely derived from competitor cells. Furthermore, the developmental block in Cbfbrss/− progenitors was present at the earliest stages of T cell development within the DN1 (ETP) and DN2 subsets. Our data define a critical CBFβ threshold for normal T cell development, and they situate an essential role of core binding factors during the earliest stages of T cell development. In addition, early thymopoiesis appeared more severely affected by reduced CBFβ dosage than by the lack of Runx1 (Ichikawa et al., Nat Med 2004; Growney et al., Blood 2005), suggesting that Runx2/3 may contribute to core binding factor activity in the T cell lineage.


Sign in / Sign up

Export Citation Format

Share Document