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Normal development and activation but altered cytokine production of Fyn-deficient CD4+ T cells  

PubMed Central

The Src family kinase, Fyn, is expressed in T cells and has been shown to phosphorylate proteins involved in TCR signaling, cytoskeletal reorganization and IL-4 production. Fyn-deficient mice have greatly decreased numbers of NKT cells, and have thymocytes and T cells with compromised responses following antibody cross-linking of their TCRs. Here we have addressed the role of Fyn in peptide/MHC class II-induced CD4+ T cell responses. In Fyn-deficient mice, CD4+ T cells expressing the DO11.10 TCR transgene developed normally, and the number and phenotype of naïve and regulatory DO11.10+CD4+ T cells in the periphery were comparable with their wild type counterparts. Conjugation with Ovap323-339 loaded APCs, and the subsequent proliferation in vitro or in vivo of DO11.10+Fyn-deficient CD4+ T cells was virtually indistinguishable from the response of DO11.10+ wild type CD4+ T cells. Proliferation of Fyn-deficient T cells was not more dependent on co-stimulation through CD28. In addition, we have found that differentiation, in vitro or in vivo, of transgenic CD4+ Fyn-deficient T cells into IL-4 secreting effector cells was unimpaired, and under certain conditions DO11.10+Fyn-deficient CD4+ T cells were more potent cytokine-producing cells than DO11.10+ wild type CD4+ T cells. These data demonstrate that ablation of Fyn expression does not alter most antigen-driven CD4+ T cell responses with the exception of cytokine production, which under some circumstances, is enhanced in Fyn-deficient CD4+ T cells.

Mamchak, Alusha A.; Sullivan, Brandon M.; Hou, Baidong; Lee, Linda M.; Gilden, Julia K.; Krummel, Matthew F.; Locksley, Richard M.; DeFranco, Anthony L.



Gadd45? Is Dispensable for Normal Mouse Development and T-Cell Proliferation  

PubMed Central

Gadd45?, a family member of the growth arrest and DNA damage-inducible gene family 45 (Gadd45), is strongly induced by interleukin-2 (IL-2) in peripheral T cells. While in most tissues all Gadd45 family members are expressed, Gadd45? is the only member that is induced by IL-2. Here we show that the IL-2-induced expression of Gadd45? is dependent on a signaling pathway mediated by the tyrosine kinase Jak3 and the transcription factors Stat5a and Stat5b (signal transducer and activator of transcription). Previous studies with ectopically overexpressed Gadd45? in various cell lines implicated its function in negative growth control. To analyze the physiological role of Gadd45? we used homologous recombination to generate mice lacking Gadd45?. Gadd45?-deficient mice develop normally, are indistinguishable from their littermates, and are fertile. Furthermore, hematopoiesis in mice lacking Gadd45? is not impaired and Gadd45?-deficient T lymphocytes show normal responses to IL-2. These data demonstrate that Gadd45? is not essential for normal mouse development and hematopoiesis, possibly due to functional redundancy among the Gadd45 family members. Gadd45? is also dispensable for IL-2-induced T-cell proliferation.

Hoffmeyer, Angelika; Piekorz, Roland; Moriggl, Richard; Ihle, James N.



Functional development of ?? T cells.  


The thymus generates T cells that are generally functionally immature and thus require peripheral activation for differentiation into effector lymphocytes. Notable exceptions to this rule are murine ?? T cells, many of which have been shown to acquire their functional potential during thymic development from late embryonic stages. Here, we review the underlying ontogenic processes and molecular differentiation mechanisms of murine ?? T cells, focusing on the transcriptional control of IFN-? and IL-17 expression. We propose that functional commitment of ?? T cells occurs in "developmental windows" defined by the molecular composition of the thymic microenvironment, such as T-cell receptor (TCR), TCR coreceptor ligands, and cytokines. We further discuss the similarities and particularities of functional development of ?? T cells in mice and humans, while highlighting some key unresolved issues for future investigation. PMID:23928962

Prinz, Immo; Silva-Santos, Bruno; Pennington, Daniel J



Rapid copper acquisition by developing murine mesothelioma: decreasing bioavailable copper slows tumor growth, normalizes vessels and promotes T cell infiltration.  


Copper, an essential trace element acquired through nutrition, is an important co-factor for pro-angiogenic factors including vascular endothelial growth factor (VEGF). Decreasing bioavailable copper has been used as an anti-angiogenic and anti-cancer strategy with promising results. However, the role of copper and its potential as a therapy in mesothelioma is not yet well understood. Therefore, we monitored copper levels in progressing murine mesothelioma tumors and analyzed the effects of lowering bioavailable copper. Copper levels in tumors and organs were assayed using atomic absorption spectrophotometry. Mesothelioma tumors rapidly sequestered copper at early stages of development, the copper was then dispersed throughout growing tumor tissues. These data imply that copper uptake may play an important role in early tumor development. Lowering bioavailable copper using the copper chelators, penicillamine, trientine or tetrathiomolybdate, slowed in vivo mesothelioma growth but did not provide any cures similar to using cisplatin chemotherapy or anti-VEGF receptor antibody therapy. The impact of copper lowering on tumor blood vessels and tumor infiltrating T cells was measured using flow cytometry and confocal microscopy. Copper lowering was associated with reduced tumor vessel diameter, reduced endothelial cell proliferation (reduced Ki67 expression) and lower surface ICAM/CD54 expression implying reduced endothelial cell activation, in a process similar to endothelial normalization. Copper lowering was also associated with a CD4(+) T cell infiltrate. In conclusion, these data suggest copper lowering is a potentially useful anti-mesothelioma treatment strategy that slows tumor growth to provide a window of opportunity for inclusion of other treatment modalities to improve patient outcomes. PMID:24013775

Crowe, Andrew; Jackaman, Connie; Beddoes, Katie M; Ricciardo, Belinda; Nelson, Delia J



Mice lacking Ly49E show normal NK cell development and provide evidence for probabilistic expression of Ly49E in NK cells and T cells.  


Ly49E is an unusual member of the Ly49 family that is expressed on fetal NK cells, epithelial T cells, and NKT cells, but not on resting adult NK cells. Ly49E(bgeo/bgeo) mice in which the Ly49E gene was disrupted by inserting a ?-geo transgene were healthy, fertile, and had normal numbers of NK and T cells in all organs examined. Their NK cells displayed normal expression of Ly49 and other NK cell receptors, killed tumor and MHC class I-deficient cells efficiently, and produced normal levels of IFN-?. In heterozygous Ly49E(+/bgeo) mice, the proportion of epidermal T cells, NKT cells, and IL-2-activated NK cells that expressed Ly49E was about half that found in wild-type mice. Surprisingly, although splenic T cells rarely expressed Ly49E, IL-2-activated splenic T cells from Ly49E(bgeo/bgeo) mice were as resistant to growth in G418 as NK cells and expressed similar levels of ?-geo transcripts, suggesting that disruption of the Ly49E locus had increased its expression in these cells to the same level as that in NK cells. Importantly, however, the proportion of G418-resistant heterozygous Ly49E(+/bgeo) cells that expressed Ly49E from the wild-type allele was similar to that observed in control cells. Collectively, these findings demonstrate that Ly49E is not required for the development or homeostasis of NK and T cell populations or for the acquisition of functional competence in NK cells and provide compelling evidence that Ly49E is expressed in a probabilistic manner in adult NK cells and T cells. PMID:21248256

Aust, Jonathan G; Gays, Frances; Hussain, Farhana; Butcher, Geoffrey W; Kist, Ralf; Peters, Heiko; Brooks, Colin G



T-cell receptor diversity prevents T-cell lymphoma development.  


Mature T-cell lymphomas (MTCLs) have an extremely poor prognosis and are much less frequent than immature T-cell leukemias. This suggests that malignant outgrowth of mature T lymphocytes is well controlled. Indeed, in a previous study we found that mature T cells are resistant to transformation with known T-cell oncogenes. Here, however, we observed that T-cell receptor (TCR) mono-/oligoclonal mature T cells from TCR transgenic (tg) mice (OT-I, P14) expressing the oncogenes NPM/ALK or ?TrkA readily developed MTCLs in T-cell-deficient recipients. Analysis of cell surface markers largely ruled out that TCR tg lymphomas were derived from T-cell precursors. Furthermore, cotransplanted non-modified TCR polyclonal T cells suppressed malignant outgrowth of oncogene expressing TCR tg T lymphocytes. A dominant role of an anti-leukemic immune response or Tregs in the control of MTCLs seems unlikely as naïve T cells derived from oncogene expressing stem cells, which should be tolerant to leukemic antigens, as well as purified CD4 and CD8 were resistant to transformation. However, our results are in line with a model in which homeostatic mechanisms that stabilize the diversity of the normal T-cell repertoire, for example, clonal competition, also control the outgrowth of potentially malignant T-cell clones. This study introduces a new innate mechanism of lymphoma control. PMID:22643706

Newrzela, S; Al-Ghaili, N; Heinrich, T; Petkova, M; Hartmann, S; Rengstl, B; Kumar, A; Jäck, H-M; Gerdes, S; Roeder, I; Hansmann, M-L; von Laer, D



MHC and T cell development.  


The ability to discriminate self from non-self is a fundamental property of the immune system. In the case of T lymphocytes, the first level of this discrimination takes place in the thymus, where most lymphocytes carrying an alphabeta T cell receptor (TCR) become tolerant to self-epitopes represented within the thymic microenvironment and differentiate into CD4+ or CD8+ single positive thymocytes. In the periphery, these subsets correspond respectively to helper and cytolytic lymphocytes able to react to non-self antigens presented in the context of MHC class II and I molecules. Apart from an early phase, the development of alphabeta T cells is based on a TCR-MHC interaction which is allele-specific and, depending on its nature, leads to either protection from apoptosis and maturation (positive selection) or physical elimination of thymocytes (negative selection). Thus, these positive and negative selection processes concomitantly allow the rescue of the useful fraction and the elimination of the potentially harmful fraction of the TCR repertoire. Recent advances have provided important elements for the comprehension of the development of alphabeta T cells. In accordance with previous in vitro studies related to differentiation of CD8+ thymocytes, in vivo derived data have established that the positive selection of CD4+ thymocytes is a peptide-specific process: it is based on the intrathymic TCR recognition of self-peptide:self-MHC molecular complexes. Despite this fact, it is now clear that the TCR reactivity to non-self MHC molecules or alloreactivity--a major characteristic of the mature TCR repertoire--does not result from intrathymic T cell selection, but rather is an intrinsic property of germline-encoded TCR domains. Finally, a significant number of experiments indicate that, in secondary lymphoid organs, a repeated TCR-MHC low affinity interaction is required to maintain the mature peripheral T cell pool and therefore the mature TCR repertoire. Such a TCR-MHC interaction-induced protection from apoptosis is remarkably reminiscent of the intrathymic positive selection phenomenon. Thus, the role of self-MHC recognition in TCR repertoire development and survival may account for the influence of MHC genotype on susceptibility to specific autoimmune diseases. PMID:11256575

Viret, C; Janeway, C A



The vast majority of CLA+ T cells are resident in normal skin.  


There are T cells within normal, noninflamed skin that most likely conduct immunosurveillance and are implicated in the development of psoriasis. We isolated T cells from normal human skin using both established and novel methods. Skin resident T cells expressed high levels of CLA, CCR4, and CCR6, and a subset expressed CCR8 and CXCR6. Skin T cells had a remarkably diverse TCR repertoire and were mostly Th1 memory effector cells with smaller subsets of central memory, Th2, and functional T regulatory cells. We isolated a surprising number of nonexpanded T cells from normal skin. To validate this finding, we counted T cells in sections of normal skin and determined that there are approximately 1 x 10(6) T cells/cm(2) normal skin and an estimated 2 x 10(10) T cells in the entire skin surface, nearly twice the number of T cells in the circulation. Moreover, we estimate that 98% of CLA(+) effector memory T cells are resident in normal skin under resting conditions. These findings demonstrate that there is a large pool of memory T cells in normal skin that can initiate and perpetuate immune reactions in the absence of T cell recruitment from the blood. PMID:16547281

Clark, Rachael A; Chong, Benjamin; Mirchandani, Nina; Brinster, Nooshin K; Yamanaka, Kei-Ichi; Dowgiert, Rebecca K; Kupper, Thomas S



Linked T Cell Receptor and Cytokine Signaling Govern the Development of the Regulatory T cell Repertoire  

PubMed Central

Summary Appropriate development of regulatory T cells (Tregs) is necessary to prevent autoimmunity. Neonatal mice, unlike adults, lack factors required for Treg development. It is unclear what these missing factors are. However, signals emanating from the TCR, CD28 and ?c-dependent cytokine receptors are required for Treg development. Herein we demonstrate that expression of a constitutively-active STAT5b transgene (STAT5b-CA) allows for Treg development in neonatal mice and restores Treg numbers in CD28?/? mice. Sequence analysis of TCR genes in STAT5b-CA Tregs indicates that ectopic STAT5 activation results in a TCR repertoire that more closely resembles that of naïve T cells. Using MHCII tetramers to identify antigen-specific T cells, we demonstrate that STAT5 signals divert thymocytes normally destined to become naïve T cells into the Treg lineage. Our data support a two-step model of Treg differentiation in which TCR/CD28 signals induce cytokine responsiveness; STAT5-inducing cytokines then complete the program of Treg differentiation.

Burchill, Matthew A.; Yang, Jianying; Vang, Kieng B.; Moon, James J.; Chu, H. Hamlet; Lio, Chan-Wang J.; Vegoe, Amanda L.; Hsieh, Chyi-Song; Jenkins, Marc K.; Farrar, Michael A.



AHR-Enhancing ?? T Cells Develop in Normal Untreated Mice and Fail to Produce IL-4/13, Unlike TH2 Cells and NKT Cells1  

PubMed Central

Allergic airway hyperresponsiveness (AHR) in OVA-sensitized and challenged mice, mediated by allergen-specific Th2 cells and Th2-like iNKT cells, develops under the influence of enhancing and inhibitory ?? T cells. The AHR-enhancing cells belong to the V?1+ ?? T cell subset, cells that are capable of increasing IL-5 and IL-13 levels in the airways in a manner like Th2 cells. They also synergize with iNKT cells in mediating AHR. However, unlike Th2 cells, the AHR-enhancers arise in untreated mice, and we show here that they exhibit their functional bias already as thymocytes, at an HSAhi maturational stage. In further contrast to Th2 cells and also unlike iNKT cells, they could not be stimulated to produce IL-4 and IL-13, consistent with their synergistic dependence on iNKT cells in mediating AHR. Mice deficient in IFN-?, TNFRp75 or IL-4 did not produce these AHR-enhancing ?? T cells, but in the absence of IFN-?, their spontaneous development was restored by adoptive transfer of IFN-? competent dendritic cells from untreated donors. Intra-peritoneal injection of OVA/alum restored development of the AHR-enhancers in all of the mutant strains, indicating that the enhancers still can be induced when they fail to develop spontaneously, and that they themselves need not express TNFRp75, IFN-? or IL-4 in order to exert their function. We conclude that both the development and the cytokine potential of the AHR-enhancing ?? T cells differs critically from that of Th2 cells and NKT cells, despite similar influences of these cell populations on AHR.

Jin, Niyun; Roark, Christina L.; Miyahara, Nobuaki; Taube, Christian; Aydintug, M. Kemal; Wands, JM; Huang, Yafei; Hahn, Youn-Soo; Gelfand, Erwin W.; O'Brien, Rebecca L.; Born, Willi K.



T Cell Recruitment in the Brain during Normal Aging  

PubMed Central

Aging-related changes in the peripheral immune response are well documented, but less is known about changes of the immune response in the central nervous system. Reactivity of microglia, effectors of the brain innate immunity, is known to increase in the aged brain, but little attention has been hitherto devoted to T cell recruitment. Data in rodents point to a gradual enhancement of T cell homing to the brain in the steady state since the middle age. Experimental findings also point to enhanced transmigration of lymphocytes as part of an amplified response of the aging brain to acute exogenous inflammatory insults. Thus, available data support the capacity of the aged brain to mount a robust immune response, in contrast with peripheral immunity decline, and indicate that such central response involves recruitment of lymphocytes. These findings open many questions, including blood-brain barrier molecular regulation and infiltrated T cell subtypes during normal aging. The crosstalk between T cells, glia, and neurons also remains to be clarified in the aged brain parenchyma. This intercellular dialogue and related signaling could be relevant for both protection of the aged brain and its vulnerability to neurological disease.

Gemechu, Jickssa M.; Bentivoglio, Marina



Septin9 is involved in T-cell development and CD8+ T-cell homeostasis.  


SEPTIN9 (SEPT9) is a filament-forming protein involved in numerous cellular processes. We have used a conditional knock out allele of Sept9 to specifically delete Sept9 in T-cells. As shown by fluorescence-activated cell sorting, loss of Sept9 at an early thymocyte stage in the thymus results in increased numbers of double-negative cells indicating that SEPT9 is involved in the transition from the double-negative stage during T-cell development. Accordingly, the relative numbers of mature T-cells in the periphery are decreased in mice with a T-cell-specific deletion of Sept9. Proliferation of Sept9-deleted CD8(+) T-cells from the spleen is decreased upon stimulation in culture. The altered T-cell homeostasis caused by the loss of Sept9 results in an increase of CD8(+) central memory T-cells. PMID:23644740

Lassen, Louise Berkhoudt; Füchtbauer, Annette; Schmitz, Alexander; Sørensen, Annette Balle; Pedersen, Finn Skou; Füchtbauer, Ernst-Martin



Ligand recognition during thymic development and ?? T cell function specification  

PubMed Central

?? T cells develop in the thymus before entering the periphery. Recent work suggests that thymic development does little to constrain ?? T cell antigen specificities, but instead determines their effector fate. When triggered through the T cell receptor, ligand-naïve ?? T cells produce IL-17, ligand-experienced cells make IFN-? and those that are strongly self-reactive make IL-4. Importantly, ?? T cells are able to make cytokines immediately upon TCR engagement. These characteristics allow ?? T cells to initiate an acute inflammatory response to pathogens and to host antigens revealed by injury. These advances warrant a fresh look at how ?? T cells may function in the immune system.

Meyer, Christina; Zeng, Xun; Chien, Yueh-hsiu



Developing T-cell migration: role of semaphorins and ephrins.  


Cell migration is a crucial event for normal T-cell development, and various ligand/receptor pairs have been implicated. Most of them, including chemokines and extracellular matrix proteins, have attractant properties on thymocytes. We discuss herein two further groups of ligand/receptor pairs, semaphorins/neuropilins and ephs/ephrins, which are constitutively expressed by thymocytes and thymic microenvironmental cells. Evidence shows that the corresponding interactions are relevant for developing T-cell migration, including the entry of bone marrow progenitor cells, migration of CD4/CD8-defined thymocyte subpopulations triggered by chemokines and/or extracellular matrix proteins, and thymocyte export. Conceptually, the data summarized here show that thymocyte migration results from a complex network of molecular interactions, which generate not only attraction, but also repulsion of migrating T-cell precursors. PMID:22815386

Mendes-da-Cruz, Daniella Arêas; Stimamiglio, Marco Augusto; Muñoz, Juan Jose; Alfaro, David; Terra-Granado, Eugênia; Garcia-Ceca, Javier; Alonso-Colmenar, Luis Miguel; Savino, Wilson; Zapata, Agustin G



Deletion of the mouse T-cell receptor beta gene enhancer blocks alphabeta T-cell development.  

PubMed Central

Intrathymic T-cell development requires temporally regulated rearrangement and expression of T-cell receptor (TCR) genes. To assess the role of the TCR beta gene transcriptional enhancer (Ebeta) in this process, mouse strains in which Ebeta is deleted were generated using homologous recombination techniques. We report that mice homozygous for the Ebeta deletion, whether a selectable marker gene is present or not, show a block in alphabeta T-cell development at the CD4-CD8- double-negative cell stage, whereas the number of gammadelta+ T cells is normal, few CD4+CD8+ double-positive thymocytes and no alphabeta+ T cells are produced. DNA-PCR and RNA-PCR analyses of thymic cells from homozygous mutants showed no evidence of TCR beta gene rearrangement although germ-line Vbeta transcripts were detected at a low level, in heterozygous T cells, the targeted allele is not rearranged. Thus, deletion of Ebeta totally prevents rearrangement, but not transcription, of the targeted beta locus. These data formally establish the critical role played by Ebeta in cis-activation of the TCR beta locus for V(D)J recombination during alphabeta T-cell development. Images Fig. 1 Fig. 3 Fig. 4 Fig. 5

Bouvier, G; Watrin, F; Naspetti, M; Verthuy, C; Naquet, P; Ferrier, P



T cell development in B cell-deficient mice. II. Serological characterization of suppressor T cell factors (TsF1) produced in normal mice and in mice treated chronically with rabbit anti-mouse IgM antibodies  

PubMed Central

Serological analysis of idiotypic specificities present in azobenzenearsonate (ABA)-specific first-order suppressor T cell factors (TsF1) from C.AL-20 and BALB/c mice revealed a significant difference between TsF from these two strains of mice. The idiotypic composition of TsF1 from BALB/c mice appears to be more heterogeneous, and at least two different fractions can be readily identified. One bears the characteristic BALB/c-associated CRI(C) (crossreactive idiotype) determinants, and the other is non-CRI(C)-bearing. Analysis of ABA- specific TsF1 from animals lacking B cells uncovered a fundamental change in the expression of their idiotypic specificities. TsF from rabbit anti-mouse IgM (anti-mu)-treated C.AL-20 mice failed to express the characteristic CRI(A) determinants. Instead, they express CRI(C) specificities. Similarly, TsF1 from anti-mu-treated BALB/c mice did not express their characteristic CRI(C) specificities, but rather express CRI(A) determinants. These experiments provide strong evidence that the Igh restriction specificity of TsF is dictated by the particular idiotypic specificities expressed. They also clearly demonstrate that B cells and their products play an important role in establishing the idiotypic composition and repertoire of suppressor T cells.



Extrathymic development of murine T cells after bone marrow transplantation  

PubMed Central

Restoring T cell competence is a significant clinical challenge in patients whose thymic function is severely compromised due to age or cytoreductive conditioning. Here, we demonstrate in mice that mesenteric LNs (MLNs) support extrathymic T cell development in euthymic and athymic recipients of bone marrow transplantation (BMT). Furthermore, in aged murine BMT recipients, the contribution of the MLNs to the generation of T cells was maintained, while the contribution of the thymus was significantly impaired. Thymic impairment resulted in a proportional increase in extrathymic-derived T cell progenitors. Extrathymic development in athymic recipients generated conventional naive TCR?? T cells with a broad V? repertoire and intact functional and proliferative potential. Moreover, in the absence of a functional thymus, immunity against known pathogens could be augmented using engineered precursor T cells with viral specificity. These findings demonstrate the potential of extrathymic T cell development for T cell reconstitution in patients with limited thymic function.

Holland, Amanda M.; Zakrzewski, Johannes L.; Tsai, Jennifer J.; Hanash, Alan M.; Dudakov, Jarrod A.; Smith, Odette M.; West, Mallory L.; Singer, Natalie V.; Brill, Jessie; Sun, Joseph C.; van den Brink, Marcel R.M.



A molecular map of T cell development.  


Using a sensitive molecular marker for positive selection, the appearance of a particular functional TCR alpha chain sequence in cells from mice bearing a transgenic beta chain, we address several aspects of intrathymic T cell development. First, by examining specific TCR prior to and after maturation, we demonstrate how a restricted TCR repertoire is positively selected from a highly diverse immature TCR repertoire. Second, since this molecular marker is enriched in cells progressing toward the CD4 lineage and depleted in cells progressing toward the CD8 lineage, a map of the developmental pathway of alphabeta thymocytes can be inferred. Third, the first cells that show clear signs of positive intrathymic selection are identified. PMID:9729038

Sant'Angelo, D B; Lucas, B; Waterbury, P G; Cohen, B; Brabb, T; Goverman, J; Germain, R N; Janeway, C A



Development and maintenance of regulatory T cells.  


Regulatory T (Treg) cells are a developmentally and functionally distinct T cell subpopulation that is engaged in sustaining immunological self-tolerance and homeostasis. The transcription factor Foxp3 plays a key role in Treg cell development and function. However, expression of Foxp3 alone is not sufficient for conferring and maintaining Treg cell function and phenotype. Complementing the insufficiency, Treg-cell-specific epigenetic changes are also critical in the process of Treg cell specification, in regulating its potential plasticity, and hence in establishing a stable lineage. Understanding how epigenetic alterations and Foxp3 expression coordinately control Treg-cell-specific gene regulation will enable better control of immune responses by targeting the generation and maintenance of Treg cells. PMID:23521883

Ohkura, Naganari; Kitagawa, Yohko; Sakaguchi, Shimon



Partial defects of T-cell development associated with poor T-cell function.  


For many years, severe combined immune deficiency diseases, which are characterized by virtual lack of circulating T cells and severe predisposition to infections since early in life, have been considered the prototypic forms of genetic defects of T-cell development. More recently, advances in genome sequencing have allowed identification of a growing number of gene defects that cause severe but incomplete defects in T-cell development, function, or both. Along with recurrent and severe infections, especially cutaneous viral infections, the clinical phenotype of these conditions is characterized by prominent immune dysregulation. PMID:23465662

Notarangelo, Luigi D



Role of regulatory T cells in the development of skin  

Microsoft Academic Search

T cells, particularly CD4+ T cells, have been associated with many aspects of skin disease. Current evidence suggests, however, that the role of CD4+ T lymphocytes in the development of cuta- neous inflammation surpasses that of pro-inflammatory activation of effector T cells that direct the immune response. T cell subtypes with regulatory capacity, such as CD4+CD25+ high Tregs, have been

Hermênio Cavalcante Lima


A novel method for the isolation of skin resident T cells from normal and diseased human skin.  


T cells resident in normal skin likely conduct immunosurveillance and are implicated in the development of inflammatory disorders such as psoriasis. This population of cells is difficult to study because existing techniques allow isolation of only few cells. We report here a novel method of isolating T cells from both normal and diseased human skin. Explants of skin cultured on three-dimensional matrices led to the outgrowth of dermal fibroblasts that elaborated T cell chemoattractant factors. These factors led to the migration of skin resident T cells out of skin explants where they could be collected and studied. Skin resident T cells isolated from explant cultures were CD45RO(+) memory T cells and expressed high levels of cutaneous lymphocyte antigen (CLA) and chemokine receptor (CCR)4. Inclusion of IL-2 and IL-15 in explant cultures produced up to a 10-fold expansion of skin-resident T cells, while maintaining the CLA(+)CCR4(+) skin-homing phenotype as well as a diverse T cell repertoire. This method also allowed efficient isolation of malignant T cells from the skin lesions of cutaneous T cell lymphoma and the isolation of tumor-infiltrating lymphocytes from primary squamous cell carcinomas and melanoma metastases. PMID:16484986

Clark, Rachael A; Chong, Benjamin F; Mirchandani, Nina; Yamanaka, Kei-Ichi; Murphy, George F; Dowgiert, Rebecca K; Kupper, Thomas S



Resistance of cultures of normal T cells to infection with murine type C viruses  

SciTech Connect

Long-term continuous cultures of normal T cells were established from C57BL/6 and BALB/c mice by using conditioned medium from concanavalin A-stimulated lymphocytes. The ability of various murine type C viruses to infect these normal T cell cultures was examined and compared with their ability to infect transformed T cells. All of the viruses examined, including a thymotropic radiation leukemia virus, were unable to infect and replicate in normal T cells but readily did so in transformed T cells.

Horak, I.; Enjuanes, L.; Lee, J.C.; Ihle, J.N.



Harnessing CD4? T cell responses in HIV vaccine development.  


CD4(+) T cells can perform a panoply of tasks to shape an effective response against a pathogen. Limited attention has been paid to the potential importance of functional CD4(+) T cell responses in the context of the development of next-generation vaccines, including HIV vaccines. Many CD4(+) T cell functions are newly appreciated and only partially understood. A workshop was held as a forum to bring together a small group of experts to exchange ideas on the role of CD4(+) T cells in developing durable functional antibody responses, via follicular helper T cells, as well as on the roles of CD4(+) T cells in other aspects of protective immunity. Here we discuss whether CD4(+) T cell responses may represent a beneficial component of an efficacious HIV vaccine. PMID:23389614

Streeck, Hendrik; D'Souza, M Patricia; Littman, Dan R; Crotty, Shane



Removal of myeloid cytokines from the cellular environment enhances T-cell development in vitro.  


The majority of T-cell development occurs in the thymus. Thymic epithelial cells are specialized cells that express NOTCH ligands and secrete specific cytokines required for normal T-cell lymphopoiesis. It has been demonstrated that OP9 cells derived from macrophage colony-stimulating factor (M-CSF)-deficient mice can support T-cell development when transduced with a NOTCH ligand, Delta-like 1 (Dll1). In this report, we have tested CSF-deficient mouse fibroblasts transduced with Dll1 for their ability to support T-cell differentiation. The data provided here demonstrate that CSF-deficient fibroblasts expressing DLL1 can support T-cell development. Indeed, co-cultures with these fibroblasts produced more T-cell progenitors compared with OP9-DL1 cultures. Addition of myeloid cytokines to OP9-DL1 co-cultures significantly inhibited T-cell development while CSF-deficient DLL1(+) fibroblasts retained partial T-cell differentiation. Taken together, these data imply that their lack of myeloid cytokines allows DLL1(+) fibroblasts to more efficiently generate T-cells. Development of this fibroblast system suggests that there is potential for generating human T-cell precursors via co-culture with human fibroblasts expressing DLL1 or DLL4. These T-cell precursors could be used for treating immunodeficient patients. PMID:23988615

Smeets, Monique F M A; Mackenzie-Kludas, Charley; Mohtashami, Mahmood; Zhang, Hui-Hua; Zúñiga-Pflücker, Juan Carlos; Izon, David J



Dok-1 overexpression promotes development of ?? natural killer T cells.  


In T cells, two members of the Dok family, Dok-1 and Dok-2, are predominantly expressed. Recent evidence suggests that they play a negative role in T-cell signaling. In order to define whether Dok proteins regulate T-cell development, we have generated transgenic mice overexpressing Dok-1 in thymocytes and peripheral T cells. We show that overexpression of Dok-1 retards the transition from the CD4(-) CD8(-) to CD4(+) CD8(+) stage. Moreover, there is a specific expansion of PLZF-expressing V?1.1(+) V?6.3(+) T cells. This subset of ?? T cells acquires innate characteristics including rapid IL-4 production following stimulation and requiring SLAM-associated adaptor protein (SAP) for their development. Moreover, Dok-1 overexpression promotes the generation of an innate-like CD8(+) T-cell population that expresses Eomesodermin. Altogether, these findings identify a novel role for Dok-1 in the regulation of thymic differentiation and in particular, in the development of PLZF(+) ?? T cells. PMID:22736313

Besin, Gilles; Yousefi, Mitra; Saba, Ingrid; Klinck, Roscoe; Pandolfi, Pier Paolo; Duplay, Pascale



Foxp3+ regulatory T cells promiscuously accept thymic signals critical for their development  

PubMed Central

Foxp3+ regulatory T cells develop in the thymus and are essential for maintaining peripheral tolerance to self tissues. We report the critical requirement for CD154 up-regulation specifically on, and during the thymic development of, Foxp3+ regulatory T cells for the induction of their clonal expansion within the medulla. In the absence of this signal, there was a severe reduction in their thymic generation and output, leading to decreased peripheral numbers. Importantly, CD40 expression on either thymic dendritic or epithelial cells was sufficient to promote the development of normal numbers of Foxp3+ regulatory T cells. This work suggests that CD154-transduced signals promote Foxp3+ regulatory T cell development and highlights the plasticity of the thymic stroma for supporting their generation. Crucially, this study demonstrates that Foxp3+ regulatory T cells can promiscuously accept a single critical signal necessary for their thymic development from different cellular sources, redefining our understanding of their generation.

Spence, Philip J.; Green, E. Allison



The Development and Function of Regulatory T Cells  

PubMed Central

Regulatory T cells [Tregs] are a critical subset of T cells that mediate peripheral tolerance. There are two types of Tregs: natural Tregs, which develop in the thymus, and induced Tregs, which are derived from naïve CD4+ T cells in the periphery. Tregs utilize a variety of mechanisms to suppress the immune response. While Tregs are critical for the peripheral maintenance of potential autoreactive T cells, they can also be detrimental by preventing effective anti-tumor responses and sterilizing immunity against pathogens. In this review, we will discuss the development of natural and induced Tregs as well as the role of Tregs in a variety of disease settings and the mechanisms they utilize for suppression.

Workman, Creg J.; Szymczak-Workman, Andrea L.; Collison, Lauren W.; Pillai, Meenu R.; Vignali, Dario A.A.



Agonist-selected T cell development requires strong T cell receptor signaling and store-operated calcium entry.  


T cell receptor (TCR) signaling driven by interaction of the TCR with specific complexes of self-peptide and the major histocompatibility complex determines T cell fate in thymic development. However, the signaling pathway through which TCR signal strength regulates distinct T cell lineages remains unknown. Here we have used mice lacking the endoplasmic reticulum Ca2+ sensors stromal interaction molecule 1 (STIM1) and STIM2 to show that STIM-induced store-operated Ca2+ entry is not essential for thymic development of conventional TCR??+ T cells but is specifically required for the development of agonist-selected T cells (regulatory T cells, invariant natural killer T cells, and TCR??+ CD8??+ intestinal intraepithelial lymphocytes). The severe impairment of agonist-selected T cell development is mainly due to a defect in interleukin-2 (IL-2) or IL-15 signaling. Thus, STIM1 and STIM2-mediated store-operated Ca2+ influx, leading to efficient activation of NFAT (nuclear factor of activated T cells), is critical for the postselection maturation of agonist-selected T cells. PMID:23499491

Oh-Hora, Masatsugu; Komatsu, Noriko; Pishyareh, Mojgan; Feske, Stefan; Hori, Shohei; Taniguchi, Masaru; Rao, Anjana; Takayanagi, Hiroshi



The role of programming in memory T-cell development  

Microsoft Academic Search

Recent studies suggest that memory T-cell differentiation continues for weeks or months following antigen clearance, although commitment to the memory lineage occurs during the effector stage of development. Several variables associated with priming, such as the duration of antigenic stimulation, degree of co-stimulation, cytokine environment, and CD4+ T-cell help, may program epigenetic qualitative differences into the ensuing effector and memory

David Masopust; Susan M Kaech; E John Wherry; Rafi Ahmed



Sin1 regulates Treg development but is not required for T cell growth and proliferation  

PubMed Central

Summary Mammalian Sin1 plays key roles in the regulation of mitogen activated protein kinase (MAPK) and mammalian target of rapamycin (mTOR) signaling. Sin1 is an essential component of mTOR complex (mTORC) 2. The function of Sin1 and mTORC2 remains largely unknown in T cells. Here we investigate Sin1 function in T cells using mice which lack Sin1 in the hematopoietic system. Sin1 deficiency blocks the mTORC2 dependent Akt phosphorylation in T cells during development and activation. Sin1 deficient T cells exhibit normal thymic cellularity and percentages of double negative, double positive and single positive CD4 and CD8 thymocytes. Sin1 deficiency does not impair T cell receptor (TCR) induced growth and proliferation, and normal CD4+ helper cell differentiation. However Sin1 deficiency results in an increased proportion of Foxp3+ natural T regulatory (nTreg) cells in the thymus. We show that the TGF-? dependent differentiation of CD4+ T cells in vitro is enhanced by the inhibition of mTOR but not loss of Sin1 function. Our results reveal that Sin1 and mTORC2 are dispensable for the development and activation of T cells but play a role in natural Treg cell differentiation.

Chang, Xing; Lazorchak, Adam S.; Liu, Dou; Su, Bing



Tgf-?1 produced by activated CD4+ T Cells Antagonizes T Cell Surveillance of Tumor Development  

PubMed Central

TGF?1 is a regulatory cytokine with a crucial function in the control of T cell tolerance to tumors. Our recent study revealed that T cell-produced TGF?1 is essential for inhibiting cytotoxic T cell responses to tumors. However, the exact TGF?1-producing T cell subset required for tumor immune evasion remains unknown. Here we showed that deletion of TGF?1 from CD8+ T cells or Foxp3+ regulatory T (Treg) cells did not protect mice against transplanted tumors. However, absence of TGF?1 produced by activated CD4+ T cells and Treg cells inhibited tumor growth, and protected mice from spontaneous prostate cancer. These findings suggest that TGF?1 produced by activated CD4+ T cells is a necessary requirement for tumor evasion from immunosurveillance.

Donkor, Moses K.; Sarkar, Abira; Li, Ming O.



Thymic T-cell development in allogeneic stem cell transplantation  

PubMed Central

Cytoreductive conditioning regimens used in the context of allogeneic hematopoietic cell transplantation (HCT) elicit deficits in innate and adaptive immunity, which predispose patients to infections. As such, transplantation outcomes depend vitally on the successful reconstruction of immune competence. Restoration of a normal peripheral T-cell pool after HCT is a slow process that requires the de novo production of naive T cells in a functionally competent thymus. However, there are several challenges to this regenerative process. Most notably, advanced age, the cytotoxic pretransplantation conditioning, and posttransplantation alloreactivity are risk factors for T-cell immune deficiency as they independently interfere with normal thymus function. Here, we discuss preclinical allogeneic HCT models and clinical observations that have contributed to a better understanding of the transplant-related thymic dysfunction. The identification of the cellular and molecular mechanisms that control regular thymopoiesis but are altered in HCT patients is expected to provide the basis for new therapies that improve the regeneration of the adaptive immune system, especially with functionally competent, naive T cells.



Monoclonal antibody (UCHL1) that recognises normal and neoplastic T cells in routinely fixed tissues.  

PubMed Central

UCHL1 is a murine monoclonal antibody that recognises a 180-185 kD determinant on CD4 (72%) and CD8 (36%) positive T cells. This antibody is effective in formalin fixed and paraffin embedded tissues, using the immunoperoxidase method. One hundred and forty three cases of malignant lymphoma were examined. Neoplastic cells in 100% of cases of Mycosis fungoides (n = 10), 83% of cases of peripheral T cell lymphoma (n = 25), and 78% of cases of (T-ALL) T acute lymphoblastic lymphoma (n = 9) were stained by this antibody. In addition, staining was seen in 100% of cases of malignant histiocytosis of the intestine (n = 13), a condition now thought to be a T cell lymphoma. Two cases of true histiocytic lymphoma were also positive. This antibody stained neither the neoplastic cells in a wide range of B cell lymphomas (n = 62) nor Reed-Sternberg cells in 16 cases of Hodgkin's disease. UCHL1 also stained neoplastic cells in four cases of granulocytic sarcoma. A panel of normal tissues was similarly studied. Staining was seen in normal T cells and mucosal intraepithelial lymphocytes, macrophages, mature myeloid cells, and endometrial stromal granulocytes. UCHL1 is a monoclonal antibody that identifies T cells in formalin fixed paraffin embedded tissues, and should prove useful for diagnosing T cell lymphomas, especially when only formalin fixed tissue is available for diagnosis. Images

Norton, A J; Ramsay, A D; Smith, S H; Beverley, P C; Isaacson, P G



CD4+ T Cell Development in a Mouse Expressing a Transgenic TCR Derived from a Regulatory T Cell  

PubMed Central

CD4+Foxp3+ regulatory T cells (Tregs) maintain peripheral tolerance and influence immune responses to foreign antigens. The thymus is an important source of Tregs, but controversy exists as to whether T cells are selected into the Treg lineage based on signals received through TCRs specific for self-peptides. To examine the specificity of TCRs expressed by Tregs and its effect on CD4+ T cell development, we generated Treg-TCR transgenic mice. Deletion of >90% of CD4+ T cells in RAG sufficient mice, and nearly 100% deletion in RAG?/? mice expressing this TCR indicate that the TCR is specific for an unknown, naturally expressed peptide in the thymus. Deletion occurs late in development, suggesting this peptide is presented by APCs in the thymic medulla. These studies are the first to describe the effects of expressing a Treg-TCR on CD4+ T cell development. The implications of our data for models of Treg selection are discussed.

DiPaolo, Richard J.; Shevach, Ethan M.



Novel agents in development for peripheral T-cell lymphoma.  


Though peripheral T-cell lymphoma (PTCL) is an area of significant unmet therapeutic need, a number of new treatment options are available for patients, especially those with relapsed or refractory disease. A plethora of drugs are now in development for PTCL, but drugs that truly target novel disease biology are noticeably absent. Combinations of T-cell centric agents could produce novel platforms of therapy to replace the relatively ineffective CHOP (cyclophosphamide, doxorubicin, vincristine, and prednisone)-based regimens. Among agents with T-cell activity are the folate analog pralatrexate, histone deacetylase inhibitors (HDACi) like romidepsin, the proteasome inhibitor bortezomib, the immunomodulatory agent lenalidomide, the purine nucleoside phosphorylase (PNP) inhibitor forodesine, the nucleoside analog gemcitabine, and BH3-only mimetics like ABT-263 and ABT-737. PMID:20359580

O'Connor, Owen A



Coronin 1-mediated naive T cell survival is essential for the development of autoimmune encephalomyelitis.  


Autoimmune encephalomyelitis is a disease of the CNS that can develop when an initial peripheral inflammatory stimulus is followed by infiltration and reactivation of T lymphocytes in the CNS. We report a crucial role for coronin 1, which is essential for maintenance of the naive T cell pool, for the development of murine experimental autoimmune encephalomyelitis (EAE), a model for multiple sclerosis. In the absence of coronin 1, immunization with myelin oligoglycoprotein (MOG(35-55)) peptide largely failed to induce EAE symptoms, despite normal mobilization of leukocyte subsets in the blood, as well as effector cytokine expression comparable with wild-type T cells on polyclonal stimulation. Susceptibility of coronin 1-deficient mice to EAE induction was restored by transfer of wild-type CD4(+) T cells, suggesting that the observed resistance of coronin 1-deficient mice to EAE development is T cell intrinsic. Importantly, although coronin 1-deficient regulatory T cells (Tregs) showed a suppressor activity comparable with wild-type Tregs, Treg depletion failed to restore EAE development in coronin 1-deficient animals. These results suggest a hitherto unrecognized role of naive T cells in the development of autoimmune encephalomyelitis and reveal coronin 1 as a crucial modulator of EAE induction. PMID:21289301

Siegmund, Kerstin; Zeis, Thomas; Kunz, Gabriele; Rolink, Ton; Schaeren-Wiemers, Nicole; Pieters, Jean



The Liver Kinase B1 (LKB1) is a central regulator of T cell development, activation, and metabolism  

PubMed Central

T cell activation leads to engagement of cellular metabolic pathways necessary to support cell proliferation and function. However, our understanding of the signal transduction pathways that regulate metabolism and their impact on T cell function remains limited. The Liver Kinase B1 (LKB1) is a serine/threonine kinase that links cellular metabolism with cell growth and proliferation. Here we demonstrate that LKB1 is a critical regulator of T cell development, viability, activation, and metabolism. T cell-specific ablation of the gene that encodes LKB1 resulted in blocked thymocyte development and a reduction in peripheral T cells. LKB1-deficient T cells exhibited defects in cell proliferation and viability, and altered glycolytic and lipid metabolism. Interestingly, loss of LKB1 promoted increased T cell activation and inflammatory cytokine production by both CD4+ and CD8+ T cells. Activation of the AMP-activated protein kinase (AMPK) was decreased in LKB1-deficient T cells. AMPK was found to mediate a subset of LKB1 functions in T lymphocytes, as mice lacking the ?1 subunit of AMPK displayed similar defects in T cell activation, metabolism, and inflammatory cytokine production, but normal T cell development and peripheral T cell homeostasis. LKB1- and AMPK?1-deficient T cells each displayed elevated mTORC1 signaling and IFN-? production that could be reversed by rapamycin treatment. Our data highlight a central role for LKB1 in T cell activation, viability, and metabolism, and suggest that LKB1-AMPK signaling negatively regulates T cell effector function through regulation of mTOR activity.

MacIver, Nancie J.; Blagih, Julianna; Saucillo, Donte C.; Tonelli, Luciana; Griss, Takla; Rathmell, Jeffrey C.; Jones, Russell G.



Function of the Nucleotide Exchange Activity of Vav1 in T cell Development and Activation*  

PubMed Central

The guanine nucleotide exchange factor (GEF) Vav1 is essential for transducing T cell antigen receptor (TCR) signals and therefore plays a critical role in the development and activation of T cells. It has been presumed that the GEF activity of Vav1 is important for its function; however, there has been no direct demonstration of this. Here, we generated mice expressing enzymatically inactive, but normally folded, Vav1 protein. Analysis of these mice showed that the GEF activity of Vav1 was necessary for the selection of thymocytes and for the optimal activation of T cells, including signal transduction to Rac1, Akt, and integrins. In contrast, the GEF activity of Vav1 was not required for TCR-induced calcium flux, activation of extracellular signal–regulated kinase (ERK) and protein kinase D1 (PKD1), and cell polarization. Thus, in T cells, the GEF activity of Vav1 is essential for some, but not all, of its functions.

Saveliev, Alexander; Vanes, Lesley; Ksionda, Olga; Rapley, Jonathan; Smerdon, Stephen J.; Rittinger, Katrin; Tybulewicz, Victor L. J.



Normal T-cell turnover in sooty mangabeys harboring active simian immunodeficiency virus infection.  


Sooty mangabeys naturally infected with simian immunodeficiency virus (SIV) remain healthy though they harbor viral loads comparable to those in rhesus macaques that progress to AIDS. To assess the immunologic basis of disease resistance in mangabeys, we compared the effect of SIV infection on T-cell regeneration in both monkey species. Measurement of the proliferation marker Ki-67 by flow cytometry showed that mangabeys harbored proliferating T cells at a level of 3 to 4% in peripheral blood irrespective of their infection status. In contrast, rhesus macaques demonstrated a naturally high fraction of proliferating T cells (7%) that increased two- to threefold following SIV infection. Ki-67(+) T cells were predominantly CD45RA(-), indicating increased proliferation of memory cells in macaques. Quantitation of an episomal DNA product of T-cell receptor alpha rearrangement (termed alpha1 circle) showed that the concentration of recent thymic emigrants in blood decreased with age over a 2-log unit range in both monkey species, consistent with age-related thymic involution. SIV infection caused a limited decrease of alpha1 circle numbers in mangabeys as well as in macaques. Dilution of alpha1 circles by T-cell proliferation likely contributed to this decrease, since alpha1 circle numbers and Ki-67(+) fractions correlated negatively. These findings are compatible with immune exhaustion mediated by abnormal T-cell proliferation, rather than with early thymic failure, in SIV-infected macaques. Normal T-cell turnover in SIV-infected mangabeys provides an explanation for the long-term maintenance of a functional immune system in these hosts. PMID:10627531

Chakrabarti, L A; Lewin, S R; Zhang, L; Gettie, A; Luckay, A; Martin, L N; Skulsky, E; Ho, D D; Cheng-Mayer, C; Marx, P A



HIV Patients Developing Primary CNS Lymphoma Lack EBV-Specific CD4+ T Cell Function Irrespective of Absolute CD4+ T Cell Counts  

PubMed Central

Background In chronic HIV infection, antiretroviral therapy–induced normalization of CD4+ T cell counts (immune reconstitution [IR]) is associated with a decreased incidence of opportunistic diseases. However, some individuals remain at risk for opportunistic diseases despite prolonged normalization of CD4+ T cell counts. Deficient Epstein-Barr virus (EBV)-specific CD4+ T cell function may explain the occurrence of EBV-associated opportunistic malignancy—such as primary central nervous system (PCNS) lymphoma—despite recovery of absolute CD4+ T cell counts. Methods and Findings Absolute CD4+ T cell counts and EBV-specific CD4+ T cell-dependent interferon-? production were assessed in six HIV-positive individuals prior to development of PCNS lymphoma (“cases”), and these values were compared with those in 16 HIV-infected matched participants with no sign of EBV-associated pathology (“matched controls”) and 11 nonmatched HIV-negative blood donors. Half of the PCNS lymphoma patients fulfilled IR criteria (defined here as CD4+ T cell counts ?500/?l blood). EBV-specific CD4+ T cells were assessed 0.5–4.7 y prior to diagnosis of lymphoma. In 0/6 cases versus 13/16 matched controls an EBV-specific CD4+ T cell response was detected (p = 0.007; confidence interval for odds ratio [0–0.40]). PCNS lymphoma patients also differed with regards to this response significantly from HIV-negative blood donors (p < 0.001, confidence interval for odds ratio [0–0.14]), but there was no evidence for a difference between HIV-negative participants and the HIV-positive matched controls (p = 0.47). Conclusions Irrespective of absolute CD4+ T cell counts, HIV-positive patients who subsequently developed PCNS lymphoma lacked EBV-specific CD4+ T cell function. Larger, ideally prospective studies are needed to confirm these preliminary data, and clarify the impact of pathogen-specific versus surrogate marker-based assessment of IR on clinical outcome.

Gasser, Olivier; Bihl, Florian K; Wolbers, Marcel; Loggi, Elisabetta; Steffen, Ingrid; Hirsch, Hans H; Gunthard, Huldrych F; Walker, Bruce D; Brander, Christian; Battegay, Manuel; Hess, Christoph



IL7 Enhances Thymic Human T Cell Development in \\  

Microsoft Academic Search

IL-7 is a central cytokine in the development of hematopoietic cells, although interspecies discrepancies have been reported. By coculturing human postnatal thymus hematopoietic progenitors and OP9-huDL1 stromal cells, we found that murine IL-7 is approximately 100-fold less potent than human IL-7 for supporting human T cell development in vitro. We investigated the role of human IL-7 in newborn BALB\\/c Rag2(-\\/-)gamma(c)(-\\/-)

Lent van A. U; W. Dontje; M. Nagasawa; R. Siamari; A. Q. Bakker; S. M. Pouw; K. A. Maijoor; K. Weijer; J. J. Cornelissen; B. Blom; Santo Di J. P; H. Spits; N. Legrand



GARP-TGF-? complexes negatively regulate regulatory T cell development and maintenance of peripheral CD4+ T cells in vivo.  


The role of surface-bound TGF-? on regulatory T cells (Tregs) and the mechanisms that mediate its functions are not well defined. We recently identified a cell-surface molecule called Glycoprotein A Repetitions Predominant (GARP), which is expressed specifically on activated Tregs and was found to bind latent TGF-? and mediate a portion of Treg suppressive activity in vitro. In this article, we address the role of GARP in regulating Treg and conventional T cell development and immune suppression in vivo using a transgenic mouse expressing GARP on all T cells. We found that, despite forced expression of GARP on all T cells, stimulation through the TCR was required for efficient localization of GARP to the cell surface. In addition, IL-2 signals enhanced GARP cell surface expression specifically on Tregs. GARP-transgenic CD4(+) T cells and Tregs, especially those expressing higher levels of GARP, were significantly reduced in the periphery. Mature Tregs, but not conventional CD4(+) T cells, were also reduced in the thymus. CD4(+) T cell reduction was more pronounced within the effector/memory subset, especially as the mouse aged. In addition, GARP-overexpressing CD4(+) T cells stimulated through the TCR displayed reduced proliferative capacity, which was restored by inhibiting TGF-? signaling. Furthermore, inhibiting TGF-? signals greatly enhanced surface expression of GARP on Tregs and blocked the induction of Foxp3 in activated CD4(+) T cells overexpressing GARP. These findings suggest a role for GARP in natural and induced Treg development through activation of bound latent TGF-? and signaling, which negatively regulates GARP expression on Tregs. PMID:23576681

Zhou, Angela X; Kozhaya, Lina; Fujii, Hodaka; Unutmaz, Derya



Essential Role of LAT in T Cell Development  

Microsoft Academic Search

The linker molecule LAT is a substrate of the tyrosine kinases activated following TCR engagement. Phosphorylated LAT binds many critical signaling molecules. The central role of this molecule in TCR-mediated signaling has been demonstrated by experiments in a LAT-deficient cell line. To probe the role of LAT in T cell development, the LAT gene was disrupted by targeting. LAT-deficient mice

Weiguo Zhang; Connie L Sommers; Deborah N Burshtyn; Christopher C Stebbins; Jan B DeJarnette; Ronald P Trible; Alexander Grinberg; Henry C Tsay; Helena M Jacobs; Craig M Kessler; Eric O Long; Paul E Love; Lawrence E Samelson



Development of Thymically-Derived Natural Regulatory T Cells  

PubMed Central

Natural regulatory T cells (nTregs) are defined by their inherent ability to establish and maintain peripheral self-tolerance. In recent years, the development of nTregs has come under close examination with the advent of FOXP3-GFP reporter mice that pinpointed the initiation of FOXP3 expression within the thymus. The mechanism and pathway of nTreg development has only recently been studied in detail and to a large degree still remains unclear. In this review, we will discuss our current understanding of nTreg lineage choice and development from a cellular and intracellular standpoint.

Bettini, Matthew L.; Vignali, Dario A.A.



Development of a novel redirected T-cell-based adoptive immunotherapy targeting human telomerase reverse transcriptase for adult T-cell leukemia.  


Although adult T-cell leukemia (ATL) has a poor prognosis, successful allogeneic hematopoietic stem cell transplantation (allo-HSCT) in some cases suggests that a cellular immune-mediated strategy can be effective. So far, however, no effective target for anti-ATL immunotherapy has been defined. Here we demonstrated for the first time that human telomerase reverse transcriptase (hTERT) is a promising therapeutic target for ATL, and we developed a novel redirected T-cell-based immunotherapy targeting hTERT. hTERT messenger RNA was produced abundantly in ATL tumor cells but not in steady-state normal cells. Rearranged human leukocyte antigen-A*24:02 (HLA-A*24:02) -restricted and hTERT461-469 nonameric peptide-specific T-cell receptor (TCR) ?/? genes were cloned from our previously established cytotoxic T lymphocyte clone (K3-1) and inserted into a novel retroviral TCR expression vector encoding small interfering RNAs for endogenous TCR genes in redirected T cells (hTERT-siTCR vector). Consequently, allogeneic or autologous gene-modified CD8(+) T cells prepared using the hTERT-siTCR vector successfully killed ATL tumor cells, but not normal cells including steady-state hematopoietic progenitors, in an HLA-A*24:02-restricted manner both in vitro and in vivo. Our experimental observations support the development of a novel hTERT-targeting redirected T-cell-based adoptive immunotherapy for ATL patients, especially those for whom suitable allo-HSCT donors are lacking. PMID:23641014

Miyazaki, Yukihiro; Fujiwara, Hiroshi; Asai, Hiroaki; Ochi, Fumihiro; Ochi, Toshiki; Azuma, Taichi; Ishida, Takashi; Okamoto, Sachiko; Mineno, Junichi; Kuzushima, Kiyotaka; Shiku, Hiroshi; Yasukawa, Masaki



Evidence That the T Cell Repertoire of Normal Rats Contains Cells with the Potential to Cause Diabetes. Characterization of the CD4 + T Cell Subset That Inhibits This Autoimmune Potential  

Microsoft Academic Search

Summary Diabetes was induced in a normal nonautoimmune rat strain by rendering the animals relatively T cell deficient using a protocol of adult thymectomy and sublethal 3' irradiation. All male rats and 70% of females developed an acute syndrome with severe loss of weight and hyperglycemia. Diabetes in these lymphopoenic rats was associated with extensive insulitis involving CD4 + and

Deborah Fowell; Don Mason


Tec family kinases: Itk signaling and the development of NKT ?? and ?? T cells.  


The Tec family tyrosine kinase interleukin-2 inducible T-cell kinase (Itk) is predominantly expressed in T cells and has been shown to be critical for the development, function and differentiation of conventional ?? T cells. However, less is known about its role in nonconventional T cells such as NKT and ?? T cells. In this minireview, we discuss evidence for a role for Itk in the development of invariant NKT ?? cells, as well as a smaller population NKT-like ?? T cells. We discuss how these cells take what could be the same signaling pathway regulated by Itk, and interpret it to give different outcomes with regards to development and function. PMID:21362141

Qi, Qian; Kannan, Arun Kumar; August, Avery



Synergistic Effects of Interleukin-7 and Pre-T Cell Receptor Signaling in Human T Cell Development*  

PubMed Central

The role of IL-7 in pre-T cell receptor (TCR) signaling during human T cell development is poorly understood. To study this, we engineered Molt3, a T cell progenitor T-acute lymphoblastic leukemia cell line, using lentiviral IL-7 receptor ? (IL-7R?) to serve as a model system. IL-7 promoted pre-TCR activation in IL-7R?hi Molt3 as illustrated by CD25 up-regulation after anti-CD3 stimulation. Anti-CD3 treatment activated Akt and Erk1/2 signaling pathways as proven using specific inhibitors, and IL-7 further enhanced both signaling pathways. The close association of IL-7R? with CD3? in the pre-TCR complex was illustrated through live imaging confocal fluorescence microscopy. These results demonstrate a direct and cooperative role of IL-7 in pre-TCR signaling.

Patel, Ekta S.; Chang, Lung-Ji



Age-associated increase in lifespan of na?ve CD4 T cells contributes to T-cell homeostasis but facilitates development of functional defects  

PubMed Central

With age, T-cell generation from the thymus is much reduced, yet a substantial naïve T-cell pool is maintained even in aged animals, suggesting that naïve T cells either persist longer or turn over faster to maintain T-cell homeostasis. We found that with age, naïve CD4 T cells became progressively longer-lived. Their longer lifespan did not depend on recognition of self-peptide/class II. Newly generated naïve T cells derived from aged stem cells had a shorter lifespan, like that of young naïve T cells. Conversely, naïve CD4 T cells derived from middle-aged thymectomized mice were longer-lived in vivo, and their development of functional defects was accelerated. These observations suggest that naïve T cells develop their longer lifespan during their sojourn in the periphery. Increased longevity of naïve CD4 T cells correlated well with reduced expression of proapoptotic molecule Bim. We suggest that the intrinsic increase in longevity helps maintain naïve T-cell homeostasis but facilitates the development of functional defects in mice.

Tsukamoto, Hirotake; Clise-Dwyer, Karen; Huston, Gail E.; Duso, Debra K.; Buck, Amanda L.; Johnson, Lawrence L.; Haynes, Laura; Swain, Susan L.



Lymphoid ?? T Cells That Develop in the Absence of Ligand Produce IL-17 Rapidly  

PubMed Central

Summary ?? T cells contribute uniquely to host immune competence, but how they do so remain unclear. Here, by analyzing T10/T22-specific ?? T cells in mice with different T10/T22 expression patterns, we find that encountering antigen in the thymus is neither required nor inhibitory for the development of these cells. Instead, ligand recognition determines which of two distinct functional subsets ?? T cells will become. When triggered through the TCR, lymphoid-?? T cells that encounter ligand during development produce IFN?, while those that develop in the absence of ligand make IL-17, a major inducer of granulopoiesis during inflammation. Indeed, we find large fractions of IL-17+ ?? T cells from the draining lymph nodes immediately after peptide/CFA immunization and days before the appearance of antigen specific IL-17+ ?? T cells. This suggests a critical role for ?? T cells as ‘initial providers’ of IL-17 in an inflammatory response to novel antigens.

Jensen, Kirk D. C.; Su, Xiaoqin; Shin, Sunny; Li, Luke; Youssef, Sawsan; Yamasaki, Sho; Steinman, Lawrence; Saito, Takashi; Locksley, Richard M.; Davis, Mark M.; Baumgarth, Nicole; Chien, Yueh-hsiu



E2A Deficiency Leads to Abnormalities in ab T-Cell Development and to Rapid Development of T-Cell Lymphomas  

Microsoft Academic Search

The E2A gene products, E12 and E47, are critical for proper early B-cell development and commitment to the B-cell lineage. Here we reveal a new role for E2A in T-lymphocyte development. Loss of E2A activity results in a partial block at the earliest stage of T-lineage development. This early T-cell phenotype precedes the development of a T-cell lymphoma which occurs




Lipid Signaling in T-Cell Development and Function  

PubMed Central

Second messenger molecules relay, amplify, and diversify cell surface receptor signals. Two important examples are phosphorylated D-myo-inositol derivatives, such as phosphoinositide lipids within cellular membranes, and soluble inositol phosphates. Here, we review how phosphoinositide metabolism generates multiple second messengers with important roles in T-cell development and function. They include soluble inositol(1,4,5)trisphosphate, long known for its Ca2+-mobilizing function, and phosphatidylinositol(3,4,5)trisphosphate, whose generation by phosphoinositide 3-kinase and turnover by the phosphatases PTEN and SHIP control a key “hub” of TCR signaling. More recent studies unveiled important second messenger functions for diacylglycerol, phosphatidic acid, and soluble inositol(1,3,4,5)tetrakisphosphate (IP4) in immune cells. Inositol(1,3,4,5)tetrakisphosphate acts as a soluble phosphatidylinositol(3,4,5)trisphosphate analog to control protein membrane recruitment. We propose that phosphoinositide lipids and soluble inositol phosphates (IPs) can act as complementary partners whose interplay could have broadly important roles in cellular signaling.

Huang, Yina H.; Sauer, Karsten



Common mechanism of chromosome inversion in B- and T-cell tumors: relevance to lymphoid development.  


An inversion of chromosome 14 present in the tumor cells of a patient with childhood acute lymphoblastic leukemia of B-cell lineage was shown to be the result of a site-specific recombination event between an immunoglobulin heavy-chain variable gene and the joining segment of a T-cell receptor alpha chain. This rearrangement resulted in the formation of a hybrid gene, part immunoglobulin and part T-cell receptor. Furthermore, this hybrid gene was transcribed into messenger RNA with a completely open reading frame. Thus, two loci felt to be normally activated at distinct and disparate points in lymphocyte development were unified and expressed in this tumor. PMID:3092355

Denny, C T; Hollis, G F; Hecht, F; Morgan, R; Link, M P; Smith, S D; Kirsch, I R



The signaling suppressor CIS controls proallergic T cell development and allergic airway inflammation.  


Transcription factors of the STAT family are critical in the cytokine-mediated functional differentiation of CD4(+) helper T cells. Signaling inhibitors of the SOCS family negatively regulate the activation of STAT proteins; however, their roles in the differentiation and function of helper T cells are not well understood. Here we found that the SOCS protein CIS, which was substantially induced by interleukin 4 (IL-4), negatively regulated the activation of STAT3, STAT5 and STAT6 in T cells. CIS-deficient mice spontaneously developed airway inflammation, and CIS deficiency in T cells led to greater susceptibility to experimental allergic asthma. CIS-deficient T cells showed enhanced differentiation into the TH2 and TH9 subsets of helper T cells. STAT5 and STAT6 regulated IL-9 expression by directly binding to the Il9 promoter. Our data thus demonstrate a critical role for CIS in controlling the proallergic generation of helper T cells. PMID:23727894

Yang, Xuexian O; Zhang, Huiyuan; Kim, Byung-Seok; Niu, Xiaoyin; Peng, Juan; Chen, Yuhong; Kerketta, Romica; Lee, Young-Hee; Chang, Seon Hee; Corry, David B; Wang, Demin; Watowich, Stephanie S; Dong, Chen



Thyrotrophin receptor-specific memory T cell responses require normal B cells in a murine model of Graves's disease  

PubMed Central

The role of B cells as antigen-presenting cells is being recognized increasingly in immune responses to infections and autoimmunity. We compared T cell responses in wild-type and B cell-deficient mice immunized with the thyrotrophin receptor (TSHR), the major autoantigen in Graves' disease. Three B cell-deficient mouse strains were studied: JHD (no B cells), mIgM (membrane-bound monoclonal IgM+ B cells) and (m + s)IgM (membrane-bound and secreted monoclonal IgM). Wild-type and B cell-deficient mice (BALB/c background) were studied 8 weeks after three injections of TSHR or control adenovirus. Only wild-type mice developed IgG class TSHR antibodies and hyperthyroidism. After challenge with TSHR antigen, splenocyte cultures were tested for cytokine production. Splenocytes from TSHR adenovirus injected wild-type and mIgM-mice, but not from JHD- or (m + s)IgM- mice, produced interferon (IFN)-? in response to TSHR protein. Concanavalin A and pokeweed mitogen induced comparable IFN-? secretion in all groups of mice except in the JHD strain in which responses were reduced. The absence in (m + s)IgM mice and presence in mIgM mice of an anamnestic response to TSHR antigen was unrelated to lymphoid cell types. Surprisingly, although TSHR-specific antibodies were undetectable, low levels of serum IgG were present in mIgM- but not (m + s)IgM mice. Moreover, IFN-? production by antigen-stimulated splenocytes correlated with IgG levels. In conclusion, T cell responses to TSHR antigen developed only in mice with IgG-secreting B cells. Consequently, in the TSHR–adenovirus model of Graves' disease, some normal B cells appear to be required for the development of memory T cells.




Thyrotrophin receptor-specific memory T cell responses require normal B cells in a murine model of Graves' disease.  


The role of B cells as antigen-presenting cells is being recognized increasingly in immune responses to infections and autoimmunity. We compared T cell responses in wild-type and B cell-deficient mice immunized with the thyrotrophin receptor (TSHR), the major autoantigen in Graves' disease. Three B cell-deficient mouse strains were studied: JHD (no B cells), mIgM (membrane-bound monoclonal IgM+ B cells) and (m + s)IgM (membrane-bound and secreted monoclonal IgM). Wild-type and B cell-deficient mice (BALB/c background) were studied 8 weeks after three injections of TSHR or control adenovirus. Only wild-type mice developed IgG class TSHR antibodies and hyperthyroidism. After challenge with TSHR antigen, splenocyte cultures were tested for cytokine production. Splenocytes from TSHR adenovirus injected wild-type and mIgM-mice, but not from JHD- or (m + s)IgM- mice, produced interferon (IFN)-gamma in response to TSHR protein. Concanavalin A and pokeweed mitogen induced comparable IFN-gamma secretion in all groups of mice except in the JHD strain in which responses were reduced. The absence in (m + s)IgM mice and presence in mIgM mice of an anamnestic response to TSHR antigen was unrelated to lymphoid cell types. Surprisingly, although TSHR-specific antibodies were undetectable, low levels of serum IgG were present in mIgM- but not (m + s)IgM mice. Moreover, IFN-gamma production by antigen-stimulated splenocytes correlated with IgG levels. In conclusion, T cell responses to TSHR antigen developed only in mice with IgG-secreting B cells. Consequently, in the TSHR-adenovirus model of Graves' disease, some normal B cells appear to be required for the development of memory T cells. PMID:14632743

Pichurin, P; Aliesky, H; Chen, C-R; Nagayama, Y; Rapoport, B; McLachlan, S M



Regulation of early T cell development by the PHD finger of histone lysine methyltransferase ASH1.  


We have previously isolated a mammalian homologue of Drosophila discsabsent, small, orhomeotic-1 (ash1) from the murine thymus, and recently shown that its SET domain methylates histone H3 lysine 36 (K36). Expression of ASH1 has been reported to be increased in NOD thymocytes in a BDC2.5 clonotype background, but its function in T cell development has remained elusive. Here we report that the ash1 gene is expressed at high levels in thymocytes of mice deficient for rag1 or tcra genes. ASH1 proteins are present at peri-nuclei and as nuclear speckles in thymocytes. Some of the nuclear ASH1 co-localize with RAG2. Expression of the evolutionarily conserved PHD finger of ASH1 impairs T cell development at the DP stage, and causes increased transcription from the HoxA9 promoter in vitro. Moreover, the C-terminal part of ASH1 interacts with HDAC1 repression complexes, suggesting that the PHD finger of ASH1 may be involved in down-regulation of genes for normal development of alphabeta T cells. PMID:17981149

Tanaka, Yujiro; Nakayama, Yasuhiro; Taniguchi, Masaru; Kioussis, Dimitris



Regulation of early T cell development by the PHD finger of histone lysine methyltransferase ASH1  

SciTech Connect

We have previously isolated a mammalian homologue of Drosophila discsabsent, small, orhomeotic-1 (ash1) from the murine thymus, and recently shown that its SET domain methylates histone H3 lysine 36 (K36). Expression of ASH1 has been reported to be increased in NOD thymocytes in a BDC2.5 clonotype background, but its function in T cell development has remained elusive. Here we report that the ash1 gene is expressed at high levels in thymocytes of mice deficient for rag1 or tcra genes. ASH1 proteins are present at peri-nuclei and as nuclear speckles in thymocytes. Some of the nuclear ASH1 co-localize with RAG2. Expression of the evolutionarily conserved PHD finger of ASH1 impairs T cell development at the DP stage, and causes increased transcription from the HoxA9 promoter in vitro. Moreover, the C-terminal part of ASH1 interacts with HDAC1 repression complexes, suggesting that the PHD finger of ASH1 may be involved in down-regulation of genes for normal development of {alpha}{beta} T cells.

Tanaka, Yujiro [Genome Structure and Expression, School of Biomedical Science, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyoku, Tokyo 113-8610 (Japan)], E-mail:; Nakayama, Yasuhiro [Department of Genetics, Yale University School of Medicine, 300 Cedar St., New Haven, CT 06510 (United States); Taniguchi, Masaru [Department of Developmental Immunology, Chiba University Graduate School of Medicine, 1-8-1 Inohana, Chuo-ku, Chiba 260-8670 (Japan); Kioussis, Dimitris [Department of Molecular Immunology, National Institute for Medical Research, The Ridgeway, Mill Hill, London NW7 1AA (United Kingdom)



Kinetics of T-cell development of umbilical cord blood transplantation in severe T-cell immunodeficiency disorders  

Microsoft Academic Search

Background: Hematopoietic stem-cell transplantation is the treatment of choice for severe primary T-cell immunodeficiencies. When an HLA-identical sibling donor is not available, an alternative donor stem-cell source is needed. In primary T-cell immunodeficiencies, T-cell–depleted HLA-haploidentical bone marrow transplantation has been particularly successful in reconstituting the T-cell immune system in many of the severe combined immunodeficiency syndrome types. However, there are

Alan P. Knutsen; Donna A. Wall



Loss of CNS IL-2 gene expression modifies brain T lymphocyte trafficking: Response of normal versus autoreactive Treg-deficient T cells  

PubMed Central

Emerging data from our lab and others suggested that dysregulation of the brain’s endogenous neuroimmunological milieu may occur with the loss of brain IL-2 gene expression and be involved in initiating processes that lead to CNS autoimmunity. We sought to test our working hypothesis that IL-2 deficiency induces endogenous changes in the CNS that play a key role in eliciting T cell homing into the brain. To accomplish this goal, we used an experimental approach that combined mouse congenic breeding and immune reconstitution. In congenic mice without brain IL-2 (two IL-2 KO alleles) that were reconstituted with a normal wild-type immune system, the loss of brain IL-2 doubled the number of T cells that trafficked into the brain in all regions quantified (hippocampus, septum, and cerebellum) compared to mice with two wild-type brain IL-2 alleles and a wild-type peripheral immune system. Congenic mice with normal brain IL-2 (two wild-type IL-2 alleles) that were immune reconstituted with autoreactive Treg-deficient T cells from IL-2 KO mice developed the expected peripheral autoimmunity (splenomegaly) and had a comparable doubling of T cell trafficking into the hippocampus and septum, whereas they exhibited an additional two-fold proclivity for the cerebellum over the septohippocampal regions. Unlike brain trafficking of wild-type T cells, the increased homing of IL-2 KO T cells to the cerebellum was independent of brain IL-2 gene expression. These findings demonstrate that brain IL-2 deficiency induces endogenous CNS changes that may lead to the development of brain autoimmunity, and that autoreative Treg-deficient IL-2 KO T cells trafficking to the brain could have a proclivity to induce cerebellar neuropathology.

Huang, Zhi; Meola, Danielle; Petitto, John M.



STAT6 expression in T cells, alveolar macrophages and bronchial biopsies of normal and asthmatic subjects  

PubMed Central

Background Asthma is characterised by increased numbers of Th2-like cells in the airways and IgE secretion. Generation of Th2 cells requires interleukin (IL)-4 and IL-13 acting through their specific receptors and activating the transcription factor, signal transducer and activator of transcription 6 (STAT6). STAT6 knockout mice fail to produce IgE, airway hyperresponsiveness and bronchoalveolar lavage eosinophilia after allergen sensitisation, suggesting a critical role for STAT6 in allergic responses. Methods We have investigated the expression of STAT6 in peripheral blood T-lymphocytes, alveolar macrophages and bronchial biopsies from 17 normal subjects and 18 mild-moderate steroid-naïve stable asthmatic patients. Results STAT6 expression was variable and was detected in T-lymphocytes, macrophages and bronchial epithelial cells from all subjects with no difference between normal and stable asthmatic subjects. Conclusions STAT6 expression in different cells suggests that it may be important in regulating the expression of not only Th2-like cytokines in T cells of man, but may also regulate STAT-inducible genes in alveolar macrophages and airway epithelial cells.



Dysfunction of irradiated thymus for the development of helper T cells  

SciTech Connect

The development of cytotoxic T cells and helper T cells in an intact or irradiated thymus was investigated. C57BL/6 (H-2b, Thy-1.2) mice were whole body-irradiated, or were irradiated with shielding over either the thymus or right leg and tail, and were transferred with 1.5 X 10(7) bone marrow cells from B10.Thy-1.1 mice (H-2b, Thy-1.1). At various days after reconstitution, thymus cells from the recipient mice were harvested and a peanut agglutinin low-binding population was isolated. This population was further treated with anti-Thy-1.2 plus complement to remove host-derived cells and was assayed for the frequency of cytotoxic T cell precursors (CTLp) and for the activity of helper T cells (Th). In the thymus of thymus-shielded and irradiated mice, Th activity reached normal control level by day 25, whereas CTLp frequency remained at a very low level during these days. In the thymus of whole body-irradiated mice, generation of CTLp was highly accelerated while that of Th was retarded, the period required for reconstitution being 25 days and more than 42 days for CTLp and Th, respectively. Preferential development of CTLp was also seen in right leg- and tail-shielded (L-T-shielded) and irradiated recipients. Histological observation indicated that Ia+ nonlymphoid cells were well preserved in the thymus of thymus-shielded and irradiated recipients, whereas in L-T-shielded and irradiated recipients, such cells in the medulla were markedly reduced in number. These results suggest strongly that the generation of Th but not CTLp is dependent on radiosensitive thymic component(s), and that such components may represent Ia+ cells themselves in the medulla or some microenvironment related to Ia+ cells.

Amagai, T.; Kina, T.; Hirokawa, K.; Nishikawa, S.; Imanishi, J.; Katsura, Y.



CXC chemokine receptor 4 expressed in T cells plays an important role in the development of collagen-induced arthritis  

PubMed Central

Introduction Chemokines and their receptors are potential therapeutic targets in rheumatoid arthritis (RA). Among these, several studies suggested the involvement of CXC chemokine 4 (CXCR4) and its ligand CXC ligand 12 (SDF-1) in RA pathogenesis. However, the role of these molecules in T-cell function is not known completely because of embryonic lethality of Cxcr4- and Cxcl12-deficient mice. In this report, we generated T cell-specific Cxcr4-deficient mice and showed that the CXCR4 in T cells is important for the development of collagen-induced arthritis (CIA). Methods T cell-specific Cxcr4-deficient mice were generated by using the Cre-loxP system. Mice harboring loxP sites flanking exon 2 of the Cxcr4gene (Cxcr4flox/flox) were generated by homologous recombination and crossed with Cre transgenic mice expressing Cre recombinase under the control of Lck promoter (Cxcr4+/+/Lck-Cremice) to generate T cell-specific Cxcr4-deficient mice (Cxcr4flox/flox/Lck-Cre mice). CIA was induced by immunization with chicken type II collagen and Complete Freund's Adjuvant (CFA). Results The incidence, but not the severity, of CIA was significantly reduced in Cxcr4flox/flox/Lck-Cre mice compared with Cxcr4+/+/Lck-Cre mice. We found that the expression of CXCR4 was enhanced in activated T cells, and the migration of Cxcr4-deficient T cells toward SDF-1 was severely impaired. However, antibody production, cellular proliferative response, and cytokine production on treatment with type II collagen (IIC) were normal in these knockout mice, suggesting that CXCR4 is not involved in T-helper functions. Interestingly, the proportion of CXCR4-expressing T cells was much increased in affected joints compared with that in draining lymph nodes in CIA-induced mice, and distribution of Cxcr4flox/flox/Lck-Cre mouse-derived T cells into affected joints was suppressed compared with that in Cxcr4+/+/Lck-Cre T cells. Conclusions These results indicate that CXCR4 expression in T cells is important for the development of CIA, by recruiting activated T cells toward inflammatory sites, and suggest that CXCR4 is a good target for the treatment of RA in humans.



Recognition of Desmoglein 3 by Autoreactive T Cells in Pemphigus Vulgaris Patients and Normals  

Microsoft Academic Search

Pemphigus vulgaris (PV) is an autoimmune blistering disease of the skin and is caused by autoantibodies against desmoglein 3 (Dsg3) on epidermal keratinocytes. Because the production of autoantibodies is presumably T cell dependent, Dsg3-specific T cell reactivity was investigated in 14 PV patients and 12 healthy donors. Peripheral blood mononuclear cells from seven PV patients with active disease showed a

Michael Hertl; Masayuki Amagai; Hema Sundaram; John Stanley; Ken Ishii; Stephen I. Katz



CCR10 is important for the development of skin-specific ??T cells by regulating their migration and location  

PubMed Central

Unlike conventional ?? T cells, which preferentially reside in secondary lymphoid organs for adaptive immune responses, various subsets of un-conventional T cells, such as the ?? T cells with innate properties, preferentially reside in epithelial tissues as the first line of defence. However, mechanisms underlying their tissue-specific development are not well understood. We herein report that among different thymic T cell subsets fetal thymic precursors of the prototypic skin intraepithelial V?3+ T lymphocytes (sIEL) were selected to display a unique pattern of homing molecules, including a high level of CCR10 expression that was important for their development into sIELs. In fetal CCR10 knockout mice, the V?3+ sIEL precursors developed normally in the thymus, but were defective in migrating into the skin. While the earlier defect in the skin-seeding by sIEL precursors was partially compensated for by their normal expansion in the skin of adult CCR10 knockout mice, the V?3+ sIELs displayed the abnormal morphology and increasingly accumulated in the dermal region of skin. These findings provide the definite evidence that CCR10 is important in the sIEL development by regulating the migration of sIEL precursors and their maintenance in proper regions of the skin and support the notion that unique homing properties of different thymic T cell subsets plays an important role in their peripheral location.

Jin, Yan; Xia, Mingcan; Sun, Allen; Saylor, Christina M.; Xiong, Na



Foxp3 programs the development and function of CD4+CD25+ regulatory T cells  

Microsoft Academic Search

CD4+CD25+ regulatory T cells are essential for the active suppression of autoimmunity. Here we report that the forkhead transcription factor Foxp3 is specifically expressed in CD4+CD25+ regulatory T cells and is required for their development. The lethal autoimmune syndrome observed in Foxp3-mutant scurfy mice and Foxp3-null mice results from a CD4+CD25+ regulatory T cell deficiency and not from a cell-intrinsic

Jason D. Fontenot; Marc A. Gavin; Alexander Y. Rudensky



The transcriptional regulator PLZF induces the development of CD44 high memory phenotype T cells.  


Transcriptional pathways controlling the development of CD44(hi) 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 CD44(hi), but not in CD44(lo), 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 CD44(hi) MP CD4(+) and CD8(+) T cells and a corresponding decrease of naïve CD44(lo) T cells. The MP CD4(+) and CD8(+) T cells produced IFNgamma 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 IFNgamma production but increased IL-4 secretion as a result of enhanced IL-4 production of the CD44(hi)CD62L(+) subset. Our data indicate that PLZF is a novel regulator of the development of CD44(hi) MP T cells with a characteristic partial innate-like phenotype. PMID:19004789

Raberger, Julia; Schebesta, Alexandra; Sakaguchi, Shinya; Boucheron, Nicole; Blomberg, K Emelie M; Berglöf, Anna; Kolbe, Thomas; Smith, C I Edvard; Rülicke, Thomas; Ellmeier, Wilfried



Modulation of T cell development by an endogenous altered peptide ligand.  


T cells potentially encounter numerous endogenous peptides during selection in the thymus and in the periphery. We examined the impact of an endogenous peptide on in vivo T cell development, using a TCR transgenic mouse model based on a hemoglobin-specific T cell clone. In these mice, the transgenic beta chains paired with endogenous alpha chains. This led to a serendipitous primary reactivity to Ser69 peptide, an altered peptide ligand of the Hbd (64-76) epitope of the parent clone. Two Ser69-reactive T cell populations were identified. A smaller population of the Ser69-reactive T cells responded both to Ser69 and Hbd (64-76). A majority reacted only to Ser69, and not to Hbd(64-76); in fact, Hbd(64-76) was a specific TCR antagonist for these Ser69-only-reactive T cells. Thus, in this unique experimental system, Ser69 became an agonist, and Hbd (64-76) was an antagonist. Endogenous presentation of the antagonist ligand in the thymus selectively eliminated the high-avidity cells, while sparing low-avidity cells in the Ser69-reactive T cell repertoire. These results highlight how specificity guides developing T cells through a network of ligands and indicate that the endogenous peptide pool has a profound effect on T cell development and repertoire. PMID:7836933

Hsu, B L; Evavold, B D; Allen, P M



Thymic Regulatory T Cell Development: Role of Signalling Pathways and Transcription Factors  

PubMed Central

Regulatory T cells (Tregs) are a subset of CD4 T cells that are key mediators of immune tolerance. Most Tregs develop in the thymus. In this review we summarise recent findings on the role of diverse signalling pathways and downstream transcription factors in thymic Treg development.

Vasanthakumar, Ajithkumar; Grigoriadis, George



Development of a human T-T cell hybridoma secreting B cell growth factor  

PubMed Central

The success of long-term culture of normal human and murine B cells has been hampered by the limited availability of soluble factors capable of maintaining proliferation of activated B lymphocytes. Previous experiments using various culture-derived supernatants in a human system were unable to separate the activities of B cell growth factor (BCGF) and interleukin 2 (IL-2) by immunochemical means. Thus, purified factors with BCGF activity in the absence of IL-2 activity have not been available for study. In the present study, normal human peripheral blood T cells were fused with the hypoxanthine/aminopterin/thymidine- sensitive human T-leukemic cell line, CEM-6. Supernatants from the resulting hybrid cells were tested for the ability to maintain proliferation of normal human B cells in a recently described assay system for human BCGF. Hybrids demonstrating BCGF activity were cloned by limiting dilution. One hybrid clone, 2B11, continued to support proliferation of B cells in both long-term cultures and 6-d assays at a level significantly above that seen with conventionally produced growth factors. No IL-2 activity was found in the supernatant from hybrid 2B11. The hybridoma supernatant was fractionated by gel filtration, and maximum proliferation of B cells was supported by the 18-20,000 mol wt protein fraction. Thus, a human T-T cell hybridoma that has BCGF activity in the absence of any demonstrable IL-2 activity has been developed. Human T-T cell hybridomas secreting discrete immunoregulatory factors should prove to be powerful tools in dissecting the mechanisms of immunoregulation of human lymphocyte function.



Development of Valpha4+ NK T cells in the early stages of embryogenesis.  

PubMed Central

The majority of T lymphocytes start to develop at around day 15 of gestation (d15)-d17 in the thymus and comprise the peripheral repertoire characterized by the expression of polymorphic T-cell antigen receptors (TCRs). Contrary to these conventional T cells, a subset of T cells, called natural killer (NK) T cells (most of them expressing an invariant TCR encoded by the Valpha14Jalpha281 gene with a 1-nt N-region), preferentially differentiates extrathymically and dominates the peripheral T-cell population at a high frequency (5% in splenic T cells and 40% in bone marrow T cells). Here, we investigated the development of NK T cells and found that the invariant Valpha14+ TCR transcripts and the circular DNA created by Valpha14 and Jalpha281 gene rearrangements can be detected in the embryo body at d9.5 of gestation and in the yolk sac and the fetal liver at d11.5-d13.5 of gestation, but not in the thymus, whereas T cells with Valpha1+ TCR expression, a major population in the thymus, were not observed at these early stages of gestation. Fluorescence-activated cell sorter analysis also demonstrated that there exist CD3+ alpha beta+ T cells, almost all of which are Valpha14/Vbeta8+ NK+ T cells, during early embryogenesis. To our knowledge, this demonstrates for the first time that a T lymphocyte subset develops in extrathymic tissues during the early stages of embryogenesis. Images Fig. 1 Fig. 4

Makino, Y; Kanno, R; Koseki, H; Taniguchi, M



NFAT proteins: key regulators of T-cell development and function  

Microsoft Academic Search

Since the discovery of the first nuclear factor of activated T cells (NFAT) protein more than a decade ago, the NFAT family of transcription factors has grown to include five members. It has also become clear that NFAT proteins have crucial roles in the development and function of the immune system. In T cells, NFAT proteins not only regulate activation

Fernando Macian



Increase in gamma\\/delta T cell receptor bearing lymphocytes in normal small bowel mucosa in latent coeliac disease  

Microsoft Academic Search

A jejunal biopsy specimen from an asymptomatic 35 year old man was studied because of a low serum titre of reticulin antibody and the finding of coeliac disease in his son. In this specimen villous structure was quite normal as was the total number of intraepithelial lymphocytes, but the number of gamma\\/delta T cell receptor bearing lymphocytes was 10 times

M Mäki; K Holm; P Collin; E Savilahti



A transgenic TCR directs the development of IL-4+ and PLZF+ innate CD4 T cells.  


MHC class II-expressing thymocytes can efficiently mediate positive selection of CD4 T cells in mice. Thymocyte-selected CD4 (T-CD4) T cells have an innate-like phenotype similar to invariant NKT cells. To investigate the development and function of T-CD4 T cells in-depth, we cloned TCR genes from T-CD4 T cells and generated transgenic mice. Remarkably, positive selection of T-CD4 TCR transgenic (T3) thymocytes occurred more efficiently when MHC class II was expressed by thymocytes than by thymic epithelial cells. Similar to polyclonal T-CD4 T cells and also invariant NKT cells, T3 CD4 T cell development is controlled by signaling lymphocyte activation molecule/signaling lymphocyte activation molecule-associated protein signaling, and the cells expressed both IL-4 and promyelocytic leukemia zinc finger (PLZF). Surprisingly, the selected T3 CD4 T cells were heterogeneous in that only half expressed IL-4 and only half expressed PLZF. IL-4- and PLZF-expressing cells were first found at the double-positive cell stage. Thus, the expression of IL-4 and PLZF seems to be determined by an unidentified event that occurs postselection and is not solely dependent on TCR specificity or the selection process, per se. Taken together, our data show for the first time, to our knowledge, that the TCR specificity regulates but does not determine the development of innate CD4 T cells by thymocytes. PMID:23776174

Zhu, Lingqiao; Qiao, Yu; Choi, Esther S; Das, Joy; Sant'angelo, Derek B; Chang, Cheong-Hee



Essential requirement of an invariant V alpha 14 T cell antigen receptor expression in the development of natural killer T cells.  

PubMed Central

NK1.1+ T [natural killer (NK) T] cells express an invariant T cell antigen receptor alpha chain (TCR alpha) encoded by V alpha 14 and J alpha 281 segments in association with a limited number of V betas, predominantly V beta 8.2. Expression of the invariant V alpha 14/J alpha 281, but not V alpha 1, TCR in transgenic mice lacking endogenous TCR alpha expression blocks the development of conventional T alpha beta cells and leads to the preferential development of V alpha 14 NK T cells, suggesting a prerequisite role of invariant V alpha 14 TCR in NK T cell development. In V beta 8.2 but not B beta 3 transgenic mice, two NK T cells with different CD3 epsilon expressions, CD3 epsilon(dim) and CD3 epsilon(high), can be identified. CD3 epsilon(high) NK T cells express surface V alpha 14/V beta 8 TCR, indicating a mature cell type, whereas CD3 epsilon(dim) NK T cells express V beta 8 without V alpha 14 TCR and no significant CD3 epsilon expression (CD3 epsilon(dim)) on the cell surface. However, the latter are positive for recombination activating gene (RAG-1 and RAG-2) mRNA, which are only expressed in the precursor or immature T cell lineage, and also possess CD3 epsilon mRNA in their cytoplasm, suggesting that CD3 epsilon(dim) NK T cells are the precursor of V alpha 14 NK T cells. Images Fig. 1 Fig. 3 Fig. 4

Taniguchi, M; Koseki, H; Tokuhisa, T; Masuda, K; Sato, H; Kondo, E; Kawano, T; Cui, J; Perkes, A; Koyasu, S; Makino, Y



Human CD4(+) T cells recognize an epitope within alpha-fetoprotein sequence and develop into TGF-beta-producing CD4(+) T cells.  


There is limited information on the influence of tumor growth on the expansion of tumor-specific TGF-beta-producing CD4(+) T cells in humans. alpha-Fetoprotein (AFP) is an oncofetal Ag and has intrinsic immunoregulatory properties. In this study, we report the identification and characterization of subsets of CD4(+) T cells that recognize an epitope within the AFP sequence (AFP(46-55)) and develop into TGF-beta-producing CD4(+) T cells. In a peptide-specific and dose-dependent manner, AFP(46-55) CD4(+) T cells produce TGF-beta, GM-CSF, and IL-2 but not Th1-, Th2-, Th17-, or Tr1-type cytokines. These cells express CTLA-4 and glucocorticoid-induced TNR receptor and inhibit T cell proliferation in a contact-dependent manner. In this study, we show that the frequency of AFP(46-55) CD4(+) T cells is significantly higher (p = 001) in patients with hepatocellular carcinoma than in healthy donors, suggesting that these cells are expanded in response to tumor Ag. In contrast, tumor necrosis-inducing treatments that are shown to improve survival rate can shift the Th1/TGF-beta-producing CD4(+) T cell balance in favor of Th1 responses. Our data demonstrate that tumor Ags may contain epitopes which activate the expansion of inducible regulatory T cells, leading to evasion of tumor control. PMID:18354237

Alisa, Akeel; Boswell, Sandra; Pathan, Ansar A; Ayaru, Lakshmana; Williams, Roger; Behboudi, Shahriar



Role of Gastric Epithelial Cell-Derived Transforming Growth Factor ? in Reduced CD4+ T Cell Proliferation and Development of Regulatory T Cells during Helicobacter pylori Infection ?  

PubMed Central

Gastric epithelial cells (GECs) express the class II major histocompatibility complex (MHC) and costimulatory molecules, enabling them to act as antigen-presenting cells (APCs) and affect local T cell responses. During Helicobacter pylori infection, GECs respond by releasing proinflammatory cytokines and by increasing the surface expression of immunologically relevant receptors, including class II MHC. The CD4+ T cell response during H. pylori infection is skewed toward a Th1 response, but these cells remain hyporesponsive. Activated T cells show decreased proliferation during H. pylori infection, and CD4+ CD25+ FoxP3+ regulatory T cells (Tregs) are present at the site of infection. In this study, we examined the mechanisms surrounding the CD4+ T cell responses during H. pylori infection and found that transforming growth factor ? (TGF-?) plays a major role in these responses. GECs produced TGF-?1 and TGF-?2 in response to infection. Activated CD4+ T cells in culture with H. pylori-treated GECs were decreased in proliferation but increased upon neutralization of TGF-?. Naïve CD4+ T cell development into Tregs was also enhanced in the presence of GEC-derived TGF-?. Herein, we demonstrate a role for GEC-produced TGF-? in the inhibition of CD4+ T cell responses seen during H. pylori infection.

Beswick, Ellen J.; Pinchuk, Iryna V.; Earley, Rachel B.; Schmitt, David A.; Reyes, Victor E.



Disruption of alpha beta but not of gamma delta T cell development by overexpression of the helix-loop-helix protein Id3 in committed T cell progenitors.  

PubMed Central

Enforced expression of Id3, which has the capacity to inhibit many basic helix-loop-helix (bHLH) transcription factors, in human CD34(+) hematopoietic progenitor cells that have not undergone T cell receptor (TCR) gene rearrangements inhibits development of the transduced cells into TCRalpha beta and gamma delta cells in a fetal thymic organ culture (FTOC). Here we document that overexpression of Id3, in progenitors that have initiated TCR gene rearrangements (pre-T cells), inhibits development into TCRalpha beta but not into TCRgamma delta T cells. Furthermore, Id3 impedes expression of recombination activating genes and downregulates pre-Talpha mRNA. These observations suggest possible mechanisms by which Id3 overexpression can differentially affect development of pre-T cells into TCRalpha beta and gamma delta cells. We also observed that cell surface CD4(-)CD8(-)CD3(-) cells with rearranged TCR genes developed from Id3-transduced but not from control-transduced pre-T cells in an FTOC. These cells had properties of both natural killer (NK) and pre-T cells. These findings suggest that bHLH factors are required to control T cell development after the T/NK developmental checkpoint.

Blom, B; Heemskerk, M H; Verschuren, M C; van Dongen, J J; Stegmann, A P; Bakker, A Q; Couwenberg, F; Res, P C; Spits, H



Transforming Growth Factor-? Signaling Curbs Thymic Negative Selection Promoting Regulatory T Cell Development  

PubMed Central

Summary Thymus-derived naturally occurring regulatory T cells (nTregs) are necessary for immunological self-tolerance. nTreg development is instructed by the T cell receptor, and can be induced by agonist antigens that trigger T cell negative selection. How T cell deletion is regulated so that nTregs are generated is unclear. Here we showed that transforming growth factor-? (TGF-?) signaling protected nTregs and antigen-stimulated conventional T cells from apoptosis. Enhanced apoptosis of TGF-? receptor-deficient nTregs was associated with high expression of pro-apoptotic proteins Bim, Bax, and Bak, and low expression of the anti-apoptotic protein Bcl-2. Ablation of Bim in mice corrected the Treg development and homeostasis defects. Our results suggest that nTreg commitment is independent of TGF-? signaling. Instead, TGF-? promotes nTreg survival by antagonizing T cell negative selection. These findings reveal a critical function for TGF-? in control of autoreactive T cell fates with important implications for understanding T cell self-tolerance mechanisms.

Ouyang, Weiming; Beckett, Omar; Ma, Qian; Li, Ming O.



A novel role for Hedgehog in T-cell receptor signaling: implications for development and immunity.  


The Hedgehog (Hh) signaling pathway is a key regulator of both embryonic development and homeostasis of adult tissues, including thymus and blood. In the thymus, Hh signals for differentiation, survival and proliferation in the early stages of T cell development, before TCR gene rearrangement. Our recent data has shown that Hh signaling also modulates T cell receptor (TCR) signal strength in more mature T lineage cells. We showed that constitutive activation of the Hh pathway in thymocytes (by transgenic expression of the transcriptional activator form of Gli2) decreased TCR signal strength with profound consequences for the thymus--allowing self-reactive T cells to escape deletion and altering T cell CD4/CD8 lineage decisions. In contrast, in the Sonic Hh deficient thymus, TCR signaling was increased, again influencing both TCR repertoire selection and CD4/8 lineage commitment. In peripheral T cells, the transcriptional changes induced by activation of the Hh signaling pathway lead to reduced T cell activation. Hh signaling also attenuated ERK phosphorylation and proliferation in mature T cells on TCR ligation. Modulation of TCR signal strength by Hh pathway activation has importance for immunity as the presence or absence of Hh in the environment in which a T cell is activated would shape the immune response. PMID:17786048

Rowbotham, Nicola J; Hager-Theodorides, Ariadne L; Furmanski, Anna L; Crompton, Tessa



Metabolic switching and fuel choice during T-cell differentiation and memory development  

PubMed Central

Summary Clearance or control of pathogens or tumors usually requires T-cell-mediated immunity. As such, understanding the mechanisms that govern the function, maintenance, and persistence of T cells will likely lead to new treatments for controlling disease. During an immune response, T-cell development is marked by striking changes in metabolism. There is a growing appreciation that these metabolic changes underlie the capacity of T cells to perform particular functions, and this has led to a recent focus on the idea that the manipulation of cellular metabolism can be used to shape adaptive immune responses. Although interest in this area has grown in the last few years, a full understanding of the metabolic control of T-cell functions, particularly during an immune response in vivo, is still lacking. In this review, we first provide a basic overview of metabolism in T cells, and then we focus on recent studies providing new or updated insights into the regulation of metabolic pathways and how they underpin T-cell differentiation and memory T-cell development.

van der Windt, Gerritje J.W.; Pearce, Erika L.



Normal T-cell response and in vivo magnetic resonance imaging of T cells loaded with HIV transactivator-peptide-derived superparamagnetic nanoparticles  

Microsoft Academic Search

The present study analyzed the feasibility of using magnetic resonance imaging (MRI) to monitor T-cell homing in vivo after loading T cells with superparamagnetic iron oxide (CLIO) nanoparticles derivatized with a peptide sequence from the transactivator protein (Tat) of HIV-1. T cells were isolated from C57BL\\/6 (B6) mice and loaded with 0, 400, 800, 1600, or 8000 ng\\/ml of FITC

Christopher H. Dodd; Hui-Chen Hsu; Wen-Jang Chu; Pingar Yang; Huang-Ge Zhang; John D. Mountz Jr; Kurt Zinn; John Forder; Lee Josephson; Ralph Weissleder; James M. Mountz



Normalization of Obesity-Associated Insulin Resistance through Immunotherapy: CD4+ T Cells Control Glucose Homeostasis  

PubMed Central

Progressive obesity and its associated metabolic syndromes represent a globally growing challenge, yet mechanistic understanding and current therapeutics are unsatisfactory. We discovered that CD4+ T-lymphocytes, resident in visceral adipose tissue (VAT), control insulin-resistance in diet-induced obese (DIO) mice and likely humans. DIO VAT-associated T cells display biased TCR-V? repertoires suggesting antigen-specific expansion. CD4+ T-lymphocyte control of glucose homeostasis is compromised in DIO when VAT accumulates pathogenic IFN?-secreting Th1 cells, overwhelming static numbers of Th2 (CD4+GATA-3+) and regulatory Foxp3+ T cells. CD4+ T cell transfer into DIO, lymphocyte-free RAGnull mice reversed weight gain and insulin resistance predominately through Th2 cells. Brief systemic treatment with ?CD3 antibody or its F(ab?)2 fragment, restores the Th1/Foxp3+ balance and reverses insulin resistance for months, despite continuing high-fat diet. The progression of obesity-associated metabolic abnormalities is physiologically under CD4+ T cell control, with expansion of adipose tissue-resident T cells that can be manipulated by immunotherapy.

Winer, Shawn; Chan, Yin; Paltser, Geoffrey; Truong, Dorothy; Tsui, Hubert; Bahrami, Jasmine; Dorfman, Ruslan; Wang, Yongqian; Zielenski, Julian; Mastronardi, Fabrizio; Maezawa, Yuko; Drucker, Daniel; Engleman, Edgar; Winer, Daniel; Dosch, H.-Michael



Kinetics of mature T-cell development in the thymus.  

PubMed Central

We have reexamined the balance between cell birth, cell maturation, and cell death in the thymus by labeling dividing thymocytes and their progeny in vivo with [3H]-thymidine, isolating clearly defined subpopulations by fluorescence-activated cell sorting, and determining the distribution of label by autoradiography. When mature thymocytes were precisely defined (as CD4+CD8- CD3+ or CD4-CD8+ CD3+) and separated from immature single positives (CD4+CD8- CD3- and CD4-CD8+ CD3-), a lag was observed in the rate of entry of [3H]thymidine into mature cells. Thus, many of the mature thymocytes appear to derive from a small nondividing cortical thymocyte pool, rather than originating directly from the earliest dividing CD4+CD8+ blasts. There was little evidence for cell division during or after mature thymocyte formation, suggesting a one-for-one differentiation from cortical cells rather than selective clonal expansion. The rate of production of mature single positive thymocytes agreed closely with estimates of the rate of export of mature T cells from the thymus and was only 3% of the rate of production of double-positive cortical thymocytes. This was compatible with a stringent selection process and extensive intrathymic cell death and suggested that no extensive negative selection occurred after the mature cells were formed.

Egerton, M; Scollay, R; Shortman, K



Does the PI3K pathway promote or antagonize regulatory T cell development and function?  

PubMed Central

Regulatory T cells (Tregs) prevent autoimmunity and inflammation by suppressing the activation of other T cells and antigen presenting cells. The role of phosphoinositide 3-kinase (PI3K) signaling in Treg is controversial. Some studies suggest that inhibition of the PI3K pathway is essential for the development of Tregs whereas other studies have shown reduced Treg numbers and function when PI3K activity is suppressed. Here we attempt to reconcile the different studies that have explored PI3K and the downstream effectors Akt, Foxo, and mTOR in regulatory T cell development and function and discuss the implications for health and therapeutic intervention.

Soond, Dalya R.; Slack, Elizabeth C. M.; Garden, Oliver A.; Patton, Daniel T.; Okkenhaug, Klaus



Analysis of the Transcriptional Program of Developing Induced Regulatory T Cells  

PubMed Central

CD25+ regulatory T cells develop in the thymus (nTregs), but may also be generated in the periphery upon stimulation of naive CD4 T cells under appropriate conditions (iTregs). To gain insight into the mechanisms governing iTreg development, we performed longitudinal transcriptional profiling of CD25+ T cells during their differentiation from uncommitted naive CD4 T cells. Microarray analysis of mRNA from CD25+ iTregs early after stimulation revealed expression of genes involved in cell cycle progression and T cell activation, which largely overlapped with genes expressed in CD25+ effector T cells (Teffs) used as a control. Whereas expression of these genes remained elevated in Teffs, it declined gradually in developing iTregs, resulting in a more quiescent phenotype in mature iTregs. A similar pattern of kinetics was observed for biological processes and for intracellular pathways over-represented within the expressed genes. A maximum dichotomy of transcriptional activity between iTregs and Teffs was reached at late stages of their maturation. Of interest, members of the FoxO and FoxM1 transcription factor family pathways exhibited a reciprocal expression pattern in iTregs and Teffs, suggesting a role of these transcription factors in determining T cell fate.

Prots, Iryna; Skapenko, Alla; Lipsky, Peter E.; Schulze-Koops, Hendrik



Role of the multichain IL-2 receptor complex in the control of normal and malignant T-cell proliferation  

SciTech Connect

Antigen-induced activation of resting T-cells induces the synthesis of interleukin-2 (IL-2), as well as the expression of specific cell surface receptors for this lymphokine. There are at least two forms of the cellular receptors for IL-2, one with a very high affinity and the other with a lower affinity. The authors have identified two IL-2 binding peptides, a 55-kd peptide reactive with the anti-Tac monoclonal antibody, and a novel 75-kd non-Tac IL-2 binding peptide. Cell lines bearing either the p55, Tac, or the p75 peptide along manifested low-affinity IL-2 binding, whereas cell lines bearing both peptides manifested both high- and low-affinity receptors. Fusion of cell membranes from low-affinity IL-2 binding cells bearing the Tac peptide alone with membranes from a cell line bearing the p75 peptide alone generates hybrid membranes bearing high-affinity receptors. They propose a multichain model for the high-affinity IL-2 receptor in which both the Tac and the p75 IL-2 binding peptides are associated in a receptor complex. In contrast to resting T-cells, human T-cell lymphotropic virus I-associated adult T-cell leukemia cells constitutively express large numbers of IL-2 receptors. Because IL-2 receptors are present on the malignant T-cells but not on normal resting cells, clinical trials have been initiated in which patients with adult T-cell leukemia are being treated with either unmodified or toxin-conjugated forms of anti-Tac monoclonal antibody directed toward this growth factor receptor. Cross-linking studies were done using (/sup 125/I) IL-2.

Waldmann, T.A.



Development of promyelocytic zinc finger and ThPOK-expressing innate gamma delta T cells is controlled by strength of TCR signaling and Id3.  


The broad-complex tramtrack and bric a brac-zinc finger transcriptional regulator (BTB-ZF), promyelocytic leukemia zinc finger (PLZF), was recently shown to control the development of the characteristic innate T cell phenotype and effector functions of NK T cells. Interestingly, the ectopic expression of PLZF was shown to push conventional T cells into an activated state that seems to be proinflammatory. The factors that control the normal expression of PLZF in lymphocytes are unknown. In this study, we show that PLZF expression is not restricted to NK T cells but is also expressed by a subset of gammadelta T cells, functionally defining distinct subsets of this innate T cell population. A second BTB-ZF gene, ThPOK, is important for the phenotype of the PLZF-expressing gammadelta T cells. Most importantly, TCR signal strength and expression of inhibitor of differentiation gene 3 control the frequency of PLZF-expressing gammadelta T cells. This study defines the factors that control the propensity of the immune system to produce potentially disease-causing T cell subsets. PMID:20038637

Alonzo, Eric S; Gottschalk, Rachel A; Das, Joy; Egawa, Takeshi; Hobbs, Robin M; Pandolfi, Pier Paolo; Pereira, Pablo; Nichols, Kim E; Koretzky, Gary A; Jordan, Martha S; Sant'Angelo, Derek B



Loss of STAT3 in CD4+ T cells prevents development of experimental autoimmune diseases.  


Th17 cells are implicated in CNS autoimmune diseases. We show that mice with targeted-deletion of Stat3 in CD4(+) T cells (CD4(Stat3)(-/-)) do not develop experimental autoimmune uveoretinitis (EAU) or experimental autoimmune encephalomyelitis. Defective Th17 differentiation noted in CD4(Stat3)(-/-) mice is compensated by exaggerated increases in Foxp3-, IL-10-, IL-4-, and IFN-gamma-expressing T cells, suggesting critical roles of STAT3 in shaping Ag-specific CD4(+) T cell repertoire. In mice with EAU, a high percentage of IL-17-expressing T cells in their peripheral lymphoid organs also secrete IFN-gamma while these double-expressors are absent in CD4(Stat3)(-/-) and wild-type mice without EAU, raising the intriguing possibility that uveitis maybe mediated by Th17 and IL-17-expressing Th1 cells. Resistance of Stat3-deficient mice to EAU derives in part from an inability of uveitogenic Th17 and Th1 cells to enter eyes or brain of the CD4(Stat3)(-/-) mouse because of the reduction in the expression of activated alpha4/beta1 integrins on CD4(Stat3)(-/-) T cells. Adoptive transfer of activated interphotoreceptor retinoid-binding protein-specific uveitogenic T cells induced in CD4(Stat3)(-/-) mice a severe EAU characterized by development of retinal folds, infiltration of inflammatory cells into the retina, and destruction of retinal architecture, underscoring our contention that the loss of STAT3 in CD4(+) T cells results in an intrinsic developmental defect that renders CD4(Stat3)(-/-) resistant to CNS inflammatory diseases. STAT3 requirement for IL-17 production by Th17, generation of double positive T cells expressing IL-17 and IFN-gamma, and for T cell trafficking into CNS tissues suggests that STAT3 may be a therapeutic target for modulating uveitis, sceritis, or multiple sclerosis. PMID:18424728

Liu, Xuebin; Lee, Yun Sang; Yu, Cheng-Rong; Egwuagu, Charles E



Loss of STAT3 in CD4+ T cells prevents development of experimental autoimmune diseases  

PubMed Central

Th17 cells are implicated in CNS autoimmune diseases. We show that mice with targeted-deletion of STAT3 in CD4+ T-cells (CD4Stat3?/?) do not develop experimental autoimmune uveoretinitis (EAU) or experimental autoimmune encephalomyelitis (EAE). Defective Th17 differentiation noted in CD4Stat3?/? mice is compensated by exaggerated increases in Foxp3-, IL-10-, IL-4- and IFN-?-expressing T-cells, suggesting critical roles of STAT3 in shaping Ag-specific CD4+ T-cell repertoire. In mice with EAU, a high percentage of IL-17-expressing-T-cells in their peripheral lymphoid organs also secretes IFN-? while these double-expressors are absent in CD4Stat3?/? and WT mice without EAU, raising intriguing possibility that uveitis maybe mediated by Th17 and IL-17-expressing Th1 cells. Resistance of STAT3-deficient mice to EAU derives in part from an inability of uveitogenic Th17 and Th1 cells to enter eyes or brain of the CD4Stat3?/? mouse because of the reduction in the expression of activated ?4/?1 integrins on CD4Stat3?/? T cells. Adoptive transfer of activated IRBP-specific uveitogenic T cells induced in CD4Stat3?/? mice a severe EAU characterized by development of retinal folds, infiltration of inflammatory cells into the retina and destruction of retinal architecture, underscoring our contention that the loss of STAT3 in CD4+ T cells results in an intrinsic developmental defect that renders CD4Stat3?/? resistant to CNS inflammatory diseases. STAT3 requirement for IL-17 production by Th17, generation of double positive T cells expressing IL-17 and IFN-? and for T-cell trafficking into CNS tissues, suggests that STAT3 may be a therapeutic target for modulating uveitis, sceritis or multiple sclerosis.

Liu, Xuebin; Lee, Yun sang; Yu, Cheng-Rong; Egwuagu, Charles E.



Induction of T-cell development by Delta-like 4-expressing fibroblasts.  


The thymus provides a unique environment for the induction of T-cell lineage commitment and differentiation, which is predicted by specific Notch ligand-receptor interactions on epithelial cells and lymphoid progenitors, respectively. Accordingly, a bone marrow-derived stromal cell line (OP9) ectopically expressing the Notch ligand Delta-like 1 (Dll1) or Dll4 (OP9-DL1 and OP9-DL4, respectively) gains the ability to recapitulate thymus-like function, supporting T-cell differentiation of both mouse and human progenitors. In this study, we extend these findings by demonstrating that, unlike the NIH3T3 cell line, mouse primary fibroblasts made to express Dll4 (mFibro-DL4) acquire the capacity to promote and support T-cell development from hematopoietic stem cells (HSCs) into TCR??(+), CD4(+) and CD8(+) T-lineage cells. However, mFibro-DL4 cells showed a lower efficiency of T-cell generation than OP9-DL4 cells did. Nevertheless, progenitor T-cells (CD117(+) CD44(+) CD25(+)) generated in HSC/mFibro-DL4 co-cultures, when intravenously transferred into immunodeficient (Rag2(-/-) ?c(-/-)) mice, home to the thymus, undergo differentiation, and give rise to mature T-cells that go on to populate the periphery. Surprisingly, primary human fibroblast cells expressing Dll4 showed very low efficiency in supporting human T-lineage differentiation, which could not be improved by blocking myelopoiesis. Nevertheless, mFibro-DL4 cells could support human T-cell lineage differentiation. Our results provide a functional framework for the induction of T-cell development using easily accessible fibroblasts made to express Dll4. These cells, which are amenable for in vitro applications, can be further utilized in the design of individualized systems for T-cell production, with implications for the treatment of immunodeficiencies. PMID:23988616

Mohtashami, Mahmood; Shah, Divya K; Kianizad, Korosh; Awong, Geneve; Zúñiga-Pflücker, Juan Carlos



Jak3 Selectively Regulates Bax and Bcl-2 Expression To Promote T-Cell Development  

PubMed Central

Jak3-deficient mice display vastly reduced numbers of lymphoid cells. Thymocytes and peripheral T cells from Jak3-deficient mice have a high apoptotic index, suggesting that Jak3 provides survival signals. Here we report that Jak3 regulates T lymphopoiesis at least in part through its selective regulation of Bax and Bcl-2. Jak3-deficient thymocytes express elevated levels of Bax and reduced levels of Bcl-2 relative to those in wild-type littermates. Notably, up-regulation of Bax in Jak3-deficient T cells is physiologically relevant, as Jak3 Bax double-null mice have marked increases in thymocyte and peripheral T-cell numbers. Rescue of T lymphopoiesis by Bax loss was selective, as mice deficient in Jak3 plus p53 or in Jak3 plus Fas remained lymphopenic. However, Bax loss failed to restore proper ratios of peripheral CD4/CD8 T cells, which are abnormally high in Jak3-null mice. Transplantation into Jak3-deficient mice of Jak3-null bone marrow transduced with a Bcl-2-expressing retrovirus also improved peripheral T-cell numbers and restored the ratio of peripheral CD4/CD8 T cells to wild-type levels. The data support the concepts that Jak kinases regulate cell survival through their selective and cell context-dependent regulation of pro- and antiapoptotic Bcl-2 family proteins and that Bax and Bcl-2 play distinct roles in T-cell development.

Wen, Renren; Wang, Demin; McKay, Catriona; Bunting, Kevin D.; Marine, Jean-Christophe; Vanin, Elio F.; Zambetti, Gerard P.; Korsmeyer, Stanley J.; Ihle, James N.; Cleveland, John L.



Newly developed multiple myeloma in a patient with primary T-cell lymphoma of bone.  


Primary non-Hodgkin's lymphoma of bone (PLB) is rare, and generally presents as a single extensive and destructive bone lesion. Histopathologically, most cases present as diffuse large B-cell lymphoma, and T-cell lymphoma is rare. By contrast, multiple myeloma is a disease defined as the neoplastic proliferation of a single clone of plasma cells producing a monoclonal immunoglobulin. We report a case of multiple myeloma that developed during treatment of PLB in a type of T-cell. A 48-yr-old man was diagnosed as T-cell PLB, stage IE, 18 months ago. The patient received the chemoradiotherapy and salvage chemotherapy for PLB. However, the lymphoma progressed with generalized bone pain, and laboratory findings showed bicytopenia and acute renal failure. On bone marrow biopsy, the patient was diagnosed as having multiple myeloma newly developed with primary T-cell lymphoma of bone. In spite of chemotherapy, the patient died of renal failure. PMID:18583898

Hwang, Jun-Eul; Cho, Sang-Hee; Kim, Ok-Ki; Shim, Hyun-Jeong; Lee, Se-Ryeon; Ahn, Jae-Sook; Yang, Duk-Hwan; Kim, Yeo-Kyeoung; Lee, Je-Jung; Kim, Hyeoung-Joon; Chung, Ik-Joo



Characterization of regulatory T cells in decidua of miscarriage cases with abnormal or normal fetal chromosomal content.  


Decreased regulatory T (Treg) cells have been reported in cases of recurrent pregnancy loss. To understand the role of Treg cells in human pregnancy, we have studied the frequency, localization and characterization of Treg cells in the decidua. The frequency of Foxp3(+) cells among CD3(+)CD8(-) cells at the decidua basalis in cases of miscarriage with a normal embryo karyotype (n=10) was significantly lower than in normally progressing pregnancies (n=10). However, those frequencies in miscarriage with an abnormal embryo karyotype were similar to normally progressing pregnancies. Next, we used flow cytometry to study Treg cell expression of the proliferation marker Ki67 and functional Treg marker CCR5. The frequency of Foxp3(+)CD4(+) T cells in miscarriage with a normal embryo (n=10) was significantly lower than those in normally progressing pregnancies (n=15) and in miscarriage with an abnormal embryo (n=14). In miscarriage with a normal embryo, the population of Ki67(-)Foxp3(+)CD4(+) T cells was significantly smaller than in normal pregnancy. However, the frequencies of Ki67(+)Foxp3(+)CD4(+) cells and CCR5(+)Foxp3(+)CD4(+) cells were not different between the three groups. These data suggest that increased Ki67(-) Treg cells in the decidua basalis may play an important role in the induction of immune tolerance, and that immune-medicated pregnancy loss may be caused by decreased Ki67(-) Treg cells in the implantation site. PMID:23432877

Inada, Kumiko; Shima, Tomoko; Nakashima, Akitoshi; Aoki, Koji; Ito, Mika; Saito, Shigeru



Control of Regulatory T Cell Development by the Transcription Factor Foxp3  

Microsoft Academic Search

Regulatory T cells engage in the maintenance of immunological self-tolerance by actively suppressing self-reactive lymphocytes. Little is known, however, about the molecular mechanism of their development. Here we show that Foxp3, which encodes a transcription factor that is genetically defective in an autoimmune and inflammatory syndrome in humans and mice, is specifically expressed in naturally arising CD4+ regulatory T cells.

Shohei Hori; Takashi Nomura; Shimon Sakaguchi



Essential And Diverse Roles For C-Myb Throughout T Cell Development  

Microsoft Academic Search

The complex process of T cell development provides an ideal model system in which to probe how the c-Myb transcription factor\\u000a functions to regulate the many cellular events in which it has been implicated as a vital player. Thymopoiesis can be investigated\\u000a both in and out of the body, and mature, peripheral T cells can be easily manipulated in tissue

Kathleen Weston


Type C virus particles in a cord T-cell line derived by co-cultivating normal human cord leukocytes and human leukaemic T cells  

Microsoft Academic Search

A recent nationwide survey of the lymphocyte subpopulations of leukaemia and lymphoma in Japan has disclosed a high incidence of adult T-cell leukaemia (ATL)1. One of the striking features of this disease is the clustering of patients in the southwestern part of Japan1,2. We have established a continuous culture line of leukaemic T cells from a patient with ATL3,4. This

Isao Miyoshi; Ichiro Kubonishi; Shizuo Yoshimoto; Tadaatsu Akagi; Yuji Ohtsuki; Yukimasa Shiraishi; Kinya Nagata; Yorio Hinuma



Opioid maintenance therapy restores CD4+ T cell function by normalizing CD4+CD25(high) regulatory T cell frequencies in heroin user.  


There is an increasing body of evidence that heroin addiction is associated with severe alterations in immune function, which might contribute to an increased risk to contract infectious diseases like hepatitis B and C or HIV. However, the impact of heroin consumption on the CD4(+) T cell compartment is not well understood. Therefore, we analyzed the frequency and functional phenotype of CD4(+) T cells as well as immune-suppressive CD4(+)CD25(high) regulatory T cells (Tregs) isolated from the peripheral blood of opiate addicts currently abusing heroin (n=27) in comparison to healthy controls (n=25) and opiate addicts currently in opioid maintenance treatment (OMT; n=27). Interestingly, we detected a significant increase in the percentage of CD4(+)CD25(high) Tregs in the peripheral blood of heroin addicted patients in contrast to patients in OMT. The proliferative response of CD4(+) T cells upon stimulation with anti-CD3 and anti-CD28 antibodies was significantly decreased in heroin users, but could be restored by depletion of CD25(high) regulatory T cells from CD4(+) T cells to similar values as observed from healthy controls and patients in OMT. These results suggest that impaired immune responses observed in heroin users are related to the expansion of CD4(+)CD25(high) Tregs and more importantly, can be restored by OMT. PMID:22613171

Riss, Gina-Lucia; Chang, Dae-In; Wevers, Carolin; Westendorf, Astrid M; Buer, Jan; Scherbaum, Norbert; Hansen, Wiebke



Molecular Heterogeneity of gamma delta T-Cell Antigen Receptors Expressed by CD4- CD8- T-Cell Clones from Normal Donors: Both Disulfide and Non-DisulfideLinked Receptors are delta TCS1+  

Microsoft Academic Search

We investigated the molecular heterogeneity of gamma delta T-cell antigen receptors (TCR) expressed on T-cell clones generated from peripheral blood lymphocytes of normal donors. Extensive molecular heterogeneity was seen at the gamma -chain level and, to a lesser extent, at the delta -chain level. Both disulfide and non-disulfide gamma delta TCR were found and use different gamma chains with similar

Hidetoshi Seki; Masanobu Nanno; Pei-Feng Chen; Kyogo Itoh; Constantin Ioannides; Robert A. Good; Chris D. Platsoucas



Rho GTPase Cdc42 is essential for human T-cell development  

PubMed Central

Background Rho GTPases are involved in the regulation of many cell functions, including some related to the actin cytoskeleton. Different Rho GTPases have been shown to be important for T-cell development in mice. However, their role in human T-cell development has not yet been explored. Design and Methods We examined the expression and activation of Rho GTPases along different stages of T-cell development in the human thymus. Early stage human thymocytes were transduced with constitutively active and dominant negative mutants of different Rho GTPases to explore their role in human T-cell development, as analyzed in fetal thymus organ cultures. The use of these mutants as well as Rho GTPase-specific inhibitors allowed us to explore the role of GTPases in thymocyte migration. Results We found that the expression of several Rho GTPases is differently regulated during successive stages of T-cell development in man, suggesting a specific role in human thymopoiesis. In chimeric fetal thymus organ culture, T-cell development was not or only mildly affected by expression of dominant negative Rac1 and Rac2, but was severely impaired in the presence of dominant negative Cdc42, associated with enhanced apoptosis and reduced proliferation. Kinetic analysis revealed that Cdc42 is necessary in human T-cell development both before and after expression of the pre-T-cell receptor. Using inhibitors and retrovirally transferred mutants of the aforementioned Rho GTPases, we showed that only Rac1 is necessary for migration of different thymocyte subsets, including the early CD34+ fraction, towards stromal cell-derived factor-1?. Constitutively active mutants of Rac1, Rac2 and Cdc42 all impaired migration towards stromal cell-derived factor-1? and T-cell development to different degrees. Conclusions This is the first report on Rho GTPases in human T-cell development, showing the essential role of Cdc42. Our data suggest that enhanced apoptotic death and reduced proliferation rather than disturbed migration explains the decreased thymopoiesis induced by dominant negative Cdc42.

Smits, Kaatje; Iannucci, Veronica; Stove, Veronique; Van Hauwe, Peter; Naessens, Evelien; Meuwissen, Pieter J.; Arien, Kevin K.; Bentahir, Mostafa; Plum, Jean; Verhasselt, Bruno



A new approach to understanding T cell development: the isolation and characterization of immature CD4-, CD8-, CD3- T cell cDNAs by subtraction cloning.  

PubMed Central

During T cell development in the mammalian thymus, immature T cells are observed that lack the cell surface markers CD4, CD8, and CD3. A subtracted cDNA library was constructed to isolate cDNAs that are specific for these immature T cells. Tissue-specific expression of 97 individual cDNAs were examined using different cell types by Northern blot analysis, and six cDNAs were analyzed by reverse transcriptase (RT) polymerase chain reaction (PCR) detection of RNA. Approximately 50% of the clones could not be detected on Northern blots, and 40% of the clones were expressed by at least one other cell-type including monocytes, mature T cells, and B cells. Eight cDNA clones appear to be specific for the CD4-, CD8-, CD3- T cell line, used to construct the library, as determined by Northern blot analysis. In addition, 330 cDNA clones were subjected to partial automated DNA sequence determination. Database searches, with both nucleotide and protein translations, revealed cDNAs that exhibit interesting similarities to human cell-cycle gene 1, platelet-derived growth factor receptor, c-fms oncogene (CSF-1) receptor, and members of the immunoglobulin gene superfamily. This approach of employing subtraction coupled with large scale partial cDNA sequence determination can be useful to identify genes that may be involved in early T cell growth, cellular recognition or differentiation. Images

Orr, S L; Gese, E; Hood, L



Foxp1 is an essential transcriptional regulator for the generation of quiescent naive T cells during thymocyte development  

PubMed Central

Proper thymocyte development is required to establish T-cell central tolerance and to generate naive T cells, both of which are essential for T-cell homeostasis and a functional immune system. Here we demonstrate that the loss of transcription factor Foxp1 results in the abnormal development of T cells. Instead of generating naive T cells, Foxp1-deficient single-positive thymocytes acquire an activated phenotype prematurely in the thymus and lead to the generation of peripheral CD4+ T and CD8+ T cells that exhibit an activated phenotype and increased apoptosis and readily produce cytokines upon T-cell receptor engagement. These results identify Foxp1 as an essential transcriptional regulator for thymocyte development and the generation of quiescent naive T cells.

Feng, Xiaoming; Ippolito, Gregory C.; Tian, Lifeng; Wiehagen, Karla; Oh, Soyoung; Sambandam, Arivazhagan; Willen, Jessica; Bunte, Ralph M.; Maika, Shanna D.; Harriss, June V.; Caton, Andrew J.; Bhandoola, Avinash



Developmental arrest of NK1.1+ T cell antigen receptor (TCR)- alpha/beta+ T cells and expansion of NK1.1+ TCR-gamma/delta+ T cell development in CD3 zeta-deficient mice  

PubMed Central

The relationship between the structure of the T cell antigen receptor (TCR)-CD3 complex and development of NK1.1+ T cells was investigated. The TCR complex of freshly isolated NK1.1+ TCR-alpha/beta+ thymocytes contained CD3 zeta homodimers and CD zeta-FcR gamma heterodimers, whereas that of the majority of NK1.1- T cells did not contain FcR gamma. The function of CD3 zeta and FcR gamma in the development of NK1.1+ T cells was determined by analyzing CD3 zeta- and FcR gamma- deficient mice. The NK1.1+ T cells from wild-type and CD3 zeta- deficient mice had equal levels of CD3 expression. However, the development of NK1.1+ TCR-alpha/beta+ T cells was almost completely disrupted in thymus and spleen in CD3 zeta-deficient mice, whereas no alteration was observed in FcR gamma-deficient mice. In contrast, the number of novel NK1.1+ TCR-gamma/delta+ thymocytes expressing a surface phenotype similar to NK1.1+ TCR-alpha/beta+ thymocytes increased approximately six times in CD3 zeta-deficient mice. These findings establish the distinct roles of the CD3 zeta chain in the development of the following different thymic T cell compartments: NK1.1- TCR+, NK1.1+ TCR-alpha/beta+, and NK1.1+ TCR-gamma/delta+ thymocytes, which cannot be replaced by CD3 eta or FcR gamma chains.



D1 and D2 Dopamine Receptor-mediated Inhibition of Activated Normal T Cell Proliferation Is Lost in Jurkat T Leukemic Cells*  

PubMed Central

Dopamine is a catecholamine neurotransmitter, which plays an important role in the regulation of T cell functions. In activated T cells from normal volunteers, stimulation of D1 and D2 dopamine receptors inhibit cell proliferation and cytokine secretion. However, there is no report yet regarding the regulatory role of D1 and D2 dopamine receptors in abnormally proliferating T cells. The present study investigates the expression and effect of activation of these dopamine receptors in Jurkat cells, a leukemic T cell line showing uncontrolled proliferation. Like normal human T cells, in Jurkat cells, D1 and D2 dopamine receptors are also expressed; however, unlike activated normal T cells, stimulation of these dopamine receptors in Jurkat cells fails to inhibit their T cell receptor-induced proliferation. This alteration is due to failure of D1 dopamine receptor-mediated activation of cyclic AMP signaling and a missense mutation at the third cytoplasmic loop of D2 dopamine receptors affecting inhibition of phosphorylation of ZAP-70, an important downstream protein transducing signal from the T cell receptor. These results help to understand the biology of abnormal proliferation of T cells in pathophysiological conditions where dopamine plays an important role.

Basu, Biswarup; Sarkar, Chandrani; Chakroborty, Debanjan; Ganguly, Subhalakshmi; Shome, Saurav; Dasgupta, Partha Sarathi; Basu, Sujit



Protecting and rescuing the effectors: roles of differentiation and survival in the control of memory T cell development  

PubMed Central

Vaccines, arguably the single most important intervention in improving human health, have exploited the phenomenon of immunological memory. The elicitation of memory T cells is often an essential part of successful long-lived protective immunity. Our understanding of T cell memory has been greatly aided by the development of TCR Tg mice and MHC tetrameric staining reagents that have allowed the precise tracking of antigen-specific T cell responses. Indeed, following acute infection or immunization, naïve T cells undergo a massive expansion culminating in the generation of a robust effector T cell population. This peak effector response is relatively short-lived and, while most effector T cells die by apoptosis, some remain and develop into memory cells. Although the molecular mechanisms underlying this cell fate decision remain incompletely defined, substantial progress has been made, particularly with regards to CD8+ T cells. For example, the effector CD8+ T cells generated during a response are heterogeneous, consisting of cells with more or less potential to develop into full-fledged memory cells. Development of CD8+ T cell memory is regulated by the transcriptional programs that control the differentiation and survival of effector T cells. While the type of antigenic stimulation and level of inflammation control effector CD8+ T cell differentiation, availability of cytokines and their ability to control expression and function of Bcl-2 family members governs their survival. These distinct differentiation and survival programs may allow for finer therapeutic intervention to control both the quality and quantity of CD8+ T cell memory. Effector to memory transition of CD4+ T cells is less well characterized than CD8+ T cells, emerging details will be discussed. This review will focus on the recent progress made in our understanding of the mechanisms underlying the development of T cell memory with an emphasis on factors controlling survival of effector T cells.

Kurtulus, Sema; Tripathi, Pulak; Hildeman, David A.



The transcription factor PU.1 is required for the development of IL9-producing T cells and allergic inflammation  

Microsoft Academic Search

CD4+ helper T cells acquire effector phenotypes that promote specialized inflammatory responses. We show that the ETS-family transcription factor PU.1 was required for the development of an interleukin 9 (IL-9)-secreting subset of helper T cells. Decreasing PU.1 expression either by conditional deletion in mouse T cells or the use of small interfering RNA in human T cells impaired IL-9 production,

Hua-Chen Chang; Sarita Sehra; Ritobrata Goswami; Weiguo Yao; Qing Yu; Gretta L Stritesky; Rukhsana Jabeen; Carl McKinley; Ayele-Nati Ahyi; Ling Han; Evelyn T Nguyen; Michael J Robertson; Narayanan B Perumal; Robert S Tepper; Stephen L Nutt; Mark H Kaplan



From the cradle to the grave: activities of GATA-3 throughout T cell development and differentiation  

PubMed Central

Summary GATA family transcription factors play multiple vital roles in hematopoiesis in many cell lineages, and in particular, T cells require GATA-3 for execution of several developmental steps. Transcriptional activation of the Gata3 gene is observed throughout T-cell development and differentiation in stage-specific fashion. GATA-3 has been described as a master regulator of T-helper 2 (Th2) cell differentiation in mature CD4+ T cells. During T-cell development in the thymus, its roles in the CD4 vs. CD8 lineage choice and at the ?-selection checkpoint are the best characterized. In contrast, its importance prior to ?-selection has been obscured both by the developmental heterogeneity of double negative (DN) 1 thymocytes and the paucity of early T-lineage progenitors (ETPs), a subpopulation of DN1 cells that contains the most immature thymic progenitors that retain potent T-lineage developmental potential. By examining multiple lines of in vivo evidence procured through the analysis of Gata3 mutant mice, we have recently demonstrated that GATA-3 is additionally required at the earliest stage of thymopoiesis for the development of the ETP population. Here, we review the characterized functions of GATA-3 at each stage of T-cell development and discuss hypothetical molecular pathways that mediate these functions.

Hosoya, Tomonori; Maillard, Ivan; Engel, James Douglas



Enterocyte expression of interleukin 7 induces development of gammadelta T cells and Peyer's patches.  


The intestinal mucosa is suggested to support extrathymic T cell development, particularly for T cell receptor (TCR)-gammadelta intraepithelial lymphocytes (IELs). TCR-gammadelta cell development requires interleukin (IL)-7; IL-7(-/)- or IL-7 receptor(-/)- mice lack TCR-gammadelta cells. Using the intestinal fatty acid binding protein (iFABP) promoter, we reinstated expression of IL-7 to mature enterocytes of IL-7(-/)- mice (iFABP-IL7). In iFABP-IL7 mice, TCR-gammadelta IELs were restored, as were cryptopatches and Peyer's patches. TCR-gammadelta cells remained absent from all other tissues. Likewise, T cell development in thymus and B cell maturation in the bone marrow and spleen retained the IL-7(-/)- phenotype. Thus, IL-7 expression by enterocytes was sufficient for extrathymic development of TCR-gammadelta cells in situ within the intestinal epithelium and was crucial for organization of mucosal lymphoid tissue. PMID:10790431

Laky, K; Lefrançois, L; Lingenheld, E G; Ishikawa, H; Lewis, J M; Olson, S; Suzuki, K; Tigelaar, R E; Puddington, L



CD16+ monocytes control T-cell subset development in immune thrombocytopenia  

PubMed Central

Immune thrombocytopenia (ITP) results from decreased platelet production and accelerated platelet destruction. Impaired CD4+ regulatory T-cell (Treg) compartment and skewed Th1 and possibly Th17 responses have been described in ITP patients. The trigger for aberrant T-cell polarization remains unknown. Because monocytes have a critical role in development and polarization of T-cell subsets, we explored the contribution of monocyte subsets in control of Treg and Th development in patients with ITP. Unlike circulating classic CD14hiCD16? subpopulation, the CD16+ monocyte subset was expanded in ITP patients with low platelet counts on thrombopoietic agents and positively correlated with T-cell CD4+IFN-?+ levels, but negatively with circulating CD4+CD25hiFoxp3+ and IL-17+ Th cells. Using a coculture model, we found that CD16+ ITP monocytes promoted the expansion of IFN-?+CD4+ cells and concomitantly inhibited the proliferation of Tregs and IL-17+ Th cells. Th-1–polarizing cytokine IL-12, secreted after direct contact of patient T-cell and CD16+ monocytes, was responsible for the inhibitory effect on Treg and IL-17+CD4+ cell proliferation. Our findings are consistent with ITP CD16+ monocytes promoting Th1 development, which in turn negatively regulates IL-17 and Treg induction. This underscores the critical role of CD16+ monocytes in the generation of potentially pathogenic Th responses in ITP.

Zhong, Hui; Bao, Weili; Li, Xiaojuan; Miller, Allison; Seery, Caroline; Haq, Naznin; Bussel, James



TAK1 is indispensable for development of T cells and prevention of colitis by the generation of regulatory T cells  

Microsoft Academic Search

Transforming growth factor (TGF)-b-activating kinase 1 (TAK1) is critical for Toll-like receptor- and tumor necrosis factor-mediated cellular responses. In B cells, TAK1 is essential for the activation of mitogen-activated protein kinases (MAPKs), but not nuclear factor-jB (NF-jB), in antigen receptor signaling. In this study, we generate T cell-specific TAK1-deficient (LckCre\\/1Tak1flox\\/flox) mice and show that TAK1 is indispensable for the maintenance

Shintaro Sato; Hideki Sanjo; Tohru Tsujimura; Jun Ninomiya-Tsuji; Masahiro Yamamoto; Taro Kawai; Osamu Takeuchi; Shizuo Akira



T cells fail to develop in the human skin-cell explants system; an inconvenient truth  

PubMed Central

Background Haplo-identical hematopoietic stem cell (HSC) transplantation is very successful in eradicating haematological tumours, but the long post-transplant T-lymphopenic phase is responsible for high morbidity and mortality rates. Clark et al. have described a skin-explant system capable of producing host-tolerant donor-HSC derived T-cells. Because this T-cell production platform has the potential to replenish the T-cell levels following transplantation, we set out to validate the skin-explant system. Results Following the published procedures, while using the same commercial components, it was impossible to reproduce the skin-explant conditions required for HSC differentiation towards mature T-cells. The keratinocyte maturation procedure resulted in fragile cells with minimum expression of delta-like ligand (DLL). In most experiments the generated cells failed to adhere to carriers or were quickly outcompeted by fibroblasts. Consequently it was not possible to reproduce cell-culture conditions required for HSC differentiation into functional T-cells. Using cell-lines over-expressing DLL, we showed that the antibodies used by Clark et al. were unable to detect native DLL, but instead stained 7AAD+ cells. Therefore, it is unlikely that the observed T-lineage commitment from HSC is mediated by DLL expressed on keratinocytes. In addition, we did confirm expression of the Notch-ligand Jagged-1 by keratinocytes. Conclusions Currently, and unfortunately, it remains difficult to explain the development or growth of T-cells described by Clark et al., but for the fate of patients suffering from lymphopenia it is essential to both reproduce and understand how these co-cultures really "work". Fortunately, alternative procedures to speed-up T-cell reconstitution are being established and validated and may become available for patients in the near future.



The development and fate of follicular helper T cells defined by an IL-21 reporter mouse.  


Germinal centers require CD4? follicular helper T cells (TFH cells), whose hallmark is expression of the transcriptional repressor Bcl-6, the chemokine receptor CXCR5 and interleukin 21 (IL-21). To track the development and fate of TFH cells, we generated an IL-21 reporter mouse by introducing sequence encoding green fluorescent protein (GFP) into the Il21 locus; these mice had expression of IL-21–GFP in CD4?CXCR5?PD-1? TFH cells. IL-21–GFP? TFH cells were multifunctional helper cells that coexpressed several cytokines, including interferon-g (IFN-g), IL-2 and IL-4. TFH cells proliferated and gave rise to transferrable memory cells with plasticity, which differentiated after recall into conventional effector helper T cells and TFH cells. Thus, we demonstrated that TFH cells were not terminally differentiated but instead retained the flexibility to be recruited into other helper T cell subsets and nonlymphoid tissues. PMID:22466669

Lüthje, Katja; Kallies, Axel; Shimohakamada, Yoko; Belz, Gabrielle T; Light, Amanda; Tarlinton, David M; Nutt, Stephen L



Development of Human T-Cell Leukemia Virus Type 1-Transformed Tumors in Rats following Suppression of T-Cell Immunity by CD80 and CD86 Blockade  

PubMed Central

Host immunity influences clinical manifestations of human T-cell leukemia virus type 1 (HTLV-1) infection. In this study, we demonstrated that HTLV-1-transformed tumors could develop in immunocompetent rats by blocking a costimulatory signal for T-cell immune responses. Four-week-old WKA/HKm rats were treated with monoclonal antibodies (MAbs) to CD80 and CD86 and subcutaneously inoculated with syngeneic HTLV-1-infected TARS-1 cells. During MAb treatment for 14 days, TARS-1 inoculation resulted in the development of solid tumors at the site of inoculation, which metastasized to the lungs. In contrast, rats not treated with MAbs promptly rejected tumor cells. Splenic T cells from MAb-treated rats indicated impairment of proliferative and cytotoxic T-lymphocyte responses against TARS-1 in vitro compared to untreated rats. However, tumors grown in MAb-treated rats regressed following withdrawal of MAb therapy. Recovery of TARS-1-specific T-cell immune responses was associated with tumor regression in these rats. Our results suggest that HTLV-1-specific cell-mediated immunity plays a critical role in immunosurveillance against HTLV-1-transformed tumor development in vivo.

Hanabuchi, Shino; Ohashi, Takashi; Koya, Yoshihiro; Kato, Hirotomo; Takemura, Fumiyo; Hirokawa, Katsuiku; Yoshiki, Takashi; Yagita, Hideo; Okumura, Ko; Kannagi, Mari



Deletion of Foxp3+ regulatory T cells in genetically targeted mice supports development of intestinal inflammation  

PubMed Central

Background Mice lacking Foxp3+ regulatory T (Treg) cells develop severe tissue inflammation in lung, skin, and liver with premature death, whereas the intestine remains uninflamed. This study aims to demonstrate the importance of Foxp3+ Treg for the activation of T cells and the development of intestinal inflammation. Methods Foxp3-GFP-DTR (human diphtheria toxin receptor) C57BL/6 mice allow elimination of Foxp3+ Treg by treatment with Dx (diphtheria toxin). The influence of Foxp3+ Treg on intestinal inflammation was tested using the CD4+ T-cell transfer colitis model in Rag?/? C57BL/6 mice and the acute DSS-colitis model. Results Continuous depletion of Foxp3+ Treg in Foxp3-GFP-DTR mice led to dramatic weight loss and death of mice by day 28. After 10 days of depletion of Foxp3+ Treg, isolated CD4+ T-cells were activated and produced extensive amounts of IFN-?, IL-13, and IL-17A. Transfer of total CD4+ T-cells isolated from Foxp3-GFP-DTR mice did not result in any changes of intestinal homeostasis in Rag?/? C57BL/6 mice. However, administration of DTx between days 14 and 18 after T-cell reconstitution, lead to elimination of Foxp3+ Treg and to immediate weight loss due to intestinal inflammation. This pro-inflammatory effect of Foxp3+ Treg depletion consecutively increased inflammatory cytokine production. Further, the depletion of Foxp3+ Treg from Foxp3-GFP-DTR mice increased the severity of acute dSS-colitis accompanied by 80% lethality of Treg-depleted mice. CD4+ effector T-cells from Foxp3+ Treg-depleted mice produced significantly more pro-inflammatory cytokines. Conclusion Intermittent depletion of Foxp3+ Treg aggravates intestinal inflammatory responses demonstrating the importance of Foxp3+ Treg for the balance at the mucosal surface of the intestine.



Kinetics of T-cell receptor-dependent antigen recognition determined in vivo by multi-spectral normalized epifluorescence laser scanning.  


Detection of multiple fluorophores in conditions of low signal represents a limiting factor for the application of in vivo optical imaging techniques in immunology where fluorescent labels report for different functional characteristics. A noninvasive in vivo Multi-Spectral Normalized Epifluorescence Laser scanning (M-SNELS) method was developed for the simultaneous and quantitative detection of multiple fluorophores in low signal to noise ratios and used to follow T-cell activation and clonal expansion. Colocalized DsRed- and GFP-labeled T cells were followed in tandem during the mounting of an immune response. Spectral unmixing was used to distinguish the overlapping fluorescent emissions representative of the two distinct cell populations and longitudinal data reported the discrete pattern of antigen-driven proliferation. Retrieved values were validated both in vitro and in vivo with flow cytometry and significant correlation between all methodologies was achieved. Noninvasive M-SNELS successfully quantified two colocalized fluorescent populations and provides a valid alternative imaging approach to traditional invasive methods for detecting T cell dynamics. PMID:22894496

Favicchio, Rosy; Zacharakis, Giannis; Oikonomaki, Katerina; Zacharopoulos, Athanasios; Mamalaki, Clio; Ripoll, Jorge



The linkage between T-cell and dendritic cell development in the mouse thymus.  


Thymic dendritic cells (DC) mediate negative selection at a relatively late stage of the T-cell developmental pathway. We present evidence that the development of thymic DC and of T-lineage cells is linked via a common precursor at an early stage of thymocyte development. T-lineage precursor populations from the adult mouse thymus, prior to T-cell receptor gene rearrangement, display a capacity to produce DC as well as T cells in the thymus, and are very efficient precursors of DC in culture. These lymphoid/DC precursors have little capacity to form myeloid cells, indicating that thymic DC are a lymphoid-related rather than myeloid-related lineage. In contrast to myeloid-related DC, granulocyte-macrophage colony-stimulating factor is not required for the development of these lymphoid-related DC in vivo or in vitro. DC can develop in mutant mice lacking mature T cells, provided the common precursors are present. However, in mutant mice lacking functional Ikaros transcription factors, there are deficiencies in lymphoid precursor cells, in mature lymphoid cells and in DC. PMID:9850850

Shortman, K; Vremec, D; Corcoran, L M; Georgopoulos, K; Lucas, K; Wu, L



Stat5 Synergizes with T Cell Receptor\\/Antigen Stimulation in the Development of Lymphoblastic Lymphoma  

Microsoft Academic Search

Signal transducer and activator of transcription (STAT) proteins are latent transcription factors that mediate a wide range of actions induced by cytokines, interferons, and growth factors. We now report the development of thymic T cell lymphoblastic lymphomas in transgenic mice in which Stat5a or Stat5b is overexpressed within the lymphoid compartment. The rate of lym- phoma induction was markedly enhanced

John A. Kelly; Rosanne Spolski; Panu E. Kovanen; Takeshi Suzuki; Julie Bollenbacher; Cynthia A. Pise-Masison; Michael F. Radonovich; Stephen Lee; Nancy A. Jenkins; Neal G. Copeland; Herbert C. Morse III; Warren J. Leonard


Clonal populations of T cells in normal elderly humans: the T cell equivalent to "benign monoclonal gammapathy" [published erratum appears in J Exp Med 1994 Mar 1;179(3):1077  

PubMed Central

To determine whether T cells, like B cells, can become clonally expanded in normal individuals as a function of age, we compared the T cell V beta repertoire of cord blood to that of peripheral blood from normal donors over 65 yr of age. T cells from elderly subjects contained expanded subsets (greater than the mean+three standard deviations) of T cell receptor (TCR) V beta populations. These expanded subsets were observed primarily among CD8, but not CD4 cells, represented up to 37.5% of all CD8 cells, and were present in most elderly subjects. An expanded V beta 5.2/3 CD8 subset and a V beta 6.7a CD8 subset from separate donors were analyzed by reverse transcriptase- polymerase chain reaction, cloning and sequencing of the TCR beta chain VDJ junction. In both cases the expanded subsets were mono- or oligoclonal while control CD4 populations were polyclonal. Using two- color flow cytometry it was possible to identify the expanded V beta 6.7a subset as CD8+ CD28-CD11b+ cells. In three of five random old subjects similar expansions of V beta subsets were found specifically in the CD8+ CD28- subpopulation, an interesting subset of cytotoxic T lymphocytes, known to lack proliferative responses to TCR stimuli. It is common practice to use the demonstration of clonality as a diagnostic indicator for T cell lymphoma/leukemia. In view of the high frequency of expanded T clones of T cells in normal elderly subjects the diagnostic usefulness of this test should be reexamined.



Conditional Knockout Mice Reveal Distinct Functions for the Global Transcriptional Coactivators CBP and p300 in T-Cell Development  

PubMed Central

The global transcriptional coactivators CREB-binding protein (CBP) and the closely related p300 interact with over 312 proteins, making them among the most heavily connected hubs in the known mammalian protein-protein interactome. It is largely uncertain, however, if these interactions are important in specific cell lineages of adult animals, as homozygous null mutations in either CBP or p300 result in early embryonic lethality in mice. Here we describe a Cre/LoxP conditional p300 null allele (p300flox) that allows for the temporal and tissue-specific inactivation of p300. We used mice carrying p300flox and a CBP conditional knockout allele (CBPflox) in conjunction with an Lck-Cre transgene to delete CBP and p300 starting at the CD4? CD8? double-negative thymocyte stage of T-cell development. Loss of either p300 or CBP led to a decrease in CD4+ CD8+ double-positive thymocytes, but an increase in the percentage of CD8+ single-positive thymocytes seen in CBP mutant mice was not observed in p300 mutants. T cells completely lacking both CBP and p300 did not develop normally and were nonexistent or very rare in the periphery, however. T cells lacking CBP or p300 had reduced tumor necrosis factor alpha gene expression in response to phorbol ester and ionophore, while signal-responsive gene expression in CBP- or p300-deficient macrophages was largely intact. Thus, CBP and p300 each supply a surprising degree of redundant coactivation capacity in T cells and macrophages, although each gene has also unique properties in thymocyte development.

Kasper, Lawryn H.; Fukuyama, Tomofusa; Biesen, Michelle A.; Boussouar, Faycal; Tong, Caili; de Pauw, Antoine; Murray, Peter J.; van Deursen, Jan M. A.; Brindle, Paul K.



Conditional knockout mice reveal distinct functions for the global transcriptional coactivators CBP and p300 in T-cell development.  


The global transcriptional coactivators CREB-binding protein (CBP) and the closely related p300 interact with over 312 proteins, making them among the most heavily connected hubs in the known mammalian protein-protein interactome. It is largely uncertain, however, if these interactions are important in specific cell lineages of adult animals, as homozygous null mutations in either CBP or p300 result in early embryonic lethality in mice. Here we describe a Cre/LoxP conditional p300 null allele (p300flox) that allows for the temporal and tissue-specific inactivation of p300. We used mice carrying p300flox and a CBP conditional knockout allele (CBPflox) in conjunction with an Lck-Cre transgene to delete CBP and p300 starting at the CD4- CD8- double-negative thymocyte stage of T-cell development. Loss of either p300 or CBP led to a decrease in CD4+ CD8+ double-positive thymocytes, but an increase in the percentage of CD8+ single-positive thymocytes seen in CBP mutant mice was not observed in p300 mutants. T cells completely lacking both CBP and p300 did not develop normally and were nonexistent or very rare in the periphery, however. T cells lacking CBP or p300 had reduced tumor necrosis factor alpha gene expression in response to phorbol ester and ionophore, while signal-responsive gene expression in CBP- or p300-deficient macrophages was largely intact. Thus, CBP and p300 each supply a surprising degree of redundant coactivation capacity in T cells and macrophages, although each gene has also unique properties in thymocyte development. PMID:16428436

Kasper, Lawryn H; Fukuyama, Tomofusa; Biesen, Michelle A; Boussouar, Fayçal; Tong, Caili; de Pauw, Antoine; Murray, Peter J; van Deursen, Jan M A; Brindle, Paul K



The critical role of STIM1-dependent Ca(2+) signalling during T-cell development and activation.  


T lymphocytes are key cellular effectors of adaptive immunity able to recognize a virtually limitless number of antigenic peptides and mount an immune response. Ca(2+) signals are crucial to the development and activation of T cells and Stromal Interaction Molecule 1 (STIM1) has been identified as a critical modulator of intracellular Ca(2+) levels in T cells. Although the role of STIM1 in T cell activation has been extensively investigated, the role of STIM1 in T cell development has been somewhat controversial. Indeed, deficiencies in STIM1 expression and function lead to both developmental defects associated with the development of autoimmunity yet also interfere with T cell activation leading to severe combined immunodeficiency signifying a multifaceted role of STIM1 in T cell physiology and pathophysiology. PMID:23906672

Samakai, Elsie; Hooper, Robert; Soboloff, Jonathan



CCR10 is important for the development of skin-specific gammadeltaT cells by regulating their migration and location.  


Unlike conventional ?? T cells, which preferentially reside in secondary lymphoid organs for adaptive immune responses, various subsets of unconventional T cells, such as the ?? T cells with innate properties, preferentially reside in epithelial tissues as the first line of defense. However, mechanisms underlying their tissue-specific development are not well understood. We report in this paper that among different thymic T cell subsets fetal thymic precursors of the prototypic skin intraepithelial V?3(+) T lymphocytes (sIELs) were selected to display a unique pattern of homing molecules, including a high level of CCR10 expression that was important for their development into sIELs. In fetal CCR10-knockout mice, the V?3(+) sIEL precursors developed normally in the thymus but were defective in migrating into the skin. Although the earlier defect in skin-seeding by sIEL precursors was partially compensated for by their normal expansion in the skin of adult CCR10-knockout mice, the V?3(+) sIELs displayed abnormal morphology and increasingly accumulated in the dermal region of the skin. These findings provide definite evidence that CCR10 is important in sIEL development by regulating the migration of sIEL precursors and their maintenance in proper regions of the skin and support the notion that unique homing properties of different thymic T cell subsets play an important role in their peripheral location. PMID:20937851

Jin, Yan; Xia, Mingcan; Sun, Allen; Saylor, Christina M; Xiong, Na



The kinase TAK1 integrates antigen and cytokine receptor signaling for T cell development, survival and function  

Microsoft Academic Search

The kinase TAK1 is critical for innate and B cell immunity. The function of TAK1 in T cells is unclear, however. We show here that T cell–specific deletion of the gene encoding TAK1 resulted in reduced development of thymocytes, especially of regulatory T cells expressing the transcription factor Foxp3. In mature thymocytes, TAK1 was required for interleukin 7–mediated survival and

Yisong Y Wan; Hongbo Chi; Min Xie; Michael D Schneider; Richard A Flavell



The mouse gut T lymphocyte, a novel type of T cell. Nature, origin, and traffic in mice in normal and graft-versus-host conditions  

PubMed Central

Lymphocytes of the mouse intestinal mucosa, identified in tissue sections or purified suspensions of intraepithelial lymphocytes as T cells (gut T lymphocytes [GTL]), were studied in normal mice or in beige mice (the equivalent of the Chediak-Higashi syndrome in man, characterized by giant granules in various cell types, including mast cells). Mice were studied in normal or in germ-free conditions, or during a graft versus host (GVH) reaction resulting from the injection of parental thymocytes into lethally irradiated F1 mice, a condition leading to massive accumulation of T lymphocytes of donor origin in the host gut mucosa. In normal as well as in GVH conditions, a high percentage of the gut IE lymphocytes contain granules (up to 80% in the beige mouse). These granules have ultrastructural, hostochemical and other features resembling those of mast cell granules; in beige mice, up to 50% of them can be shown to contain histamine. Granulated T cells are also found in the lamina propria. It appears that the GTL may progressively lose their surface T antigens when the granules become more developed. Kinetics of [3H]TdR labeling of the GTL, transfer experiments with T cells of various origins, selective [3H]TdR labeling and selective irradiation of the Peyer's patches (PP), and effect of thoraic duct (TD) drainage led to the conclusion that GTL are the progeny of T cells stimulated to divide in the PP microenvironment, which endows them with a gut-homing tendency. From the PP, these cells follow a cycle, migrating to the TD and to the blood to colonize the whole intestinal mucosa, the majority of them as dividing cells undergoing a single round of traffic, with some probably able to recirculate and becoming a more long-lived variety. Antigenic stimulation within the PP is necessary for the emergence of GTL progenitors, but their gut-homing property is unrelated to the antigen as shown with fetal gut grafts, notably in GVH where grafts syngeneic to the host or donor become similarly infiltrated by GTL. On the basis of their properties and of further evidence to be reported elsewhere, it is proposed that GTL belong to a special class of T lymphocytes, related to the immune defenses of the mucosal systems in general, and capable of acting as progenitors of mucosal mast cells.



T-cell receptor gamma delta-expressing intraepithelial lymphocytes are present in normal and chronically inflamed human gingiva.  

PubMed Central

The phenotypic profile of leucocytes in diseased and normal gingival tissue was studied in situ and in isolated gingival mononuclear cell (GMC) preparations. T-cell receptor (TcR)gamma delta + cells showed preferential localization to epithelium, both in normal and inflamed gingiva, and were present in crevicular as well as oral epithelium. In normal gingiva > or = 30% of the isolated leucocytes expressed TcR gamma delta, of which the majority were CD4- CD8-, and expressed CD45RA. The proportion of TcR gamma delta + cells in GMC from periodontitis tissue varied between 2 and 32%. In contrast to normal gingiva the majority of TcR gamma delta + cells in diseased tissue were CD8+ and expressed CD45RO. Thus expression of the CD8 antigen on gingival TcR gamma delta + cells is probably a consequence of immune activation. Numerous Langerhans' cells and keratinocytes expressing the major histocompatibility complex (MHC) class I-like antigen, CD1, were present within normal and inflamed gingival epithelium in close proximity to the TcR gamma delta + cells. Most CD1a+ cells were scattered within oral epithelium. CD1c+ cells were localized close to the basal layer of crevicular epithelium. No CD1b+ cells were found. TcR alpha beta + cells, CD4+ and B cells were restricted to lamina propria of periodontitis lesions. The presence of intraepithelial TcR gamma delta + cells in normal gingiva suggests that they constitute the 'first line of defence' against the potentially harmful microflora in the oral cavity. Induction of CD8 and CD45RO antigens on TcR gamma delta + cells in periodontitis tissue indicate that they play a significant role in the disease. CD1 molecules on Langerhans' cells and keratinocytes may be the restriction elements for the CD8+ TcR gamma delta + cells. Images Figure 1 Figure 2 Figure 3

Lundqvist, C; Hammarstrom, M L



Molecular Determinants of Regulatory T Cell Development: The Essential Roles of Epigenetic Changes  

PubMed Central

Regulatory T (Treg) cells constitute a distinct T cell subset, which plays a key role in immune tolerance and homeostasis. The transcription factor Foxp3 controls a substantial part of Treg cell development and function. Yet its expression alone is insufficient for conferring developmental and functional characteristics of Treg cells. There is accumulating evidence that concurrent induction of Treg-specific epigenetic changes and Foxp3 expression is crucial for lineage specification and functional stability of Treg cells. This review discusses recent progress in our understanding of molecular features of Treg cells, in particular, the molecular basis of how a population of developing T cells is driven to the Treg cell lineage and how its function is stably maintained.

Kitagawa, Yohko; Ohkura, Naganari; Sakaguchi, Shimon



Ablation of the kinase NDR1 predisposes mice to the development of T cell lymphoma.  


Defective apoptosis contributes to the development of various human malignancies. The kinases nuclear Dbf2-related 1 (NDR1) and NDR2 mediate apoptosis downstream of the tumor suppressor proteins RASSF1A (Ras association domain family member 1A) and MST1 (mammalian Ste20-like kinase 1). To further analyze the role of NDR1 in apoptosis, we generated NDR1-deficient mice. Although NDR1 is activated by both intrinsic and extrinsic proapoptotic stimuli, which indicates a role for NDR1 in regulating apoptosis, NDR1-deficient T cells underwent apoptosis in a manner similar to that of wild-type cells in response to different proapoptotic stimuli. Analysis of the abundances of NDR1 and NDR2 proteins revealed that loss of NDR1 was functionally compensated for by an increase in the abundance of NDR2 protein. Despite this compensation, NDR1(-/-) and NDR1(+/-) mice were more prone to the development of T cell lymphomas than were wild-type mice. Tumor development in mice and humans was accompanied by a decrease in the overall amounts of NDR proteins in T cell lymphoma samples. Thus, reduction in the abundance of NDR1 triggered a decrease in the total amount of both isoforms. Together, our data suggest that a reduction in the abundances of the NDR proteins results in defective responses to proapoptotic stimuli, thereby facilitating the development of tumors. PMID:20551432

Cornils, Hauke; Stegert, Mario R; Hergovich, Alexander; Hynx, Debby; Schmitz, Debora; Dirnhofer, Stephan; Hemmings, Brian A



Regulation of early T cell development by the PHD finger of histone lysine methyltransferase ASH1  

Microsoft Academic Search

We have previously isolated a mammalian homologue of Drosophila discsabsent, small, orhomeotic-1 (ash1) from the murine thymus, and recently shown that its SET domain methylates histone H3 lysine 36 (K36). Expression of ASH1 has been reported to be increased in NOD thymocytes in a BDC2.5 clonotype background, but its function in T cell development has remained elusive. Here we report

Yujiro Tanaka; Yasuhiro Nakayama; Masaru Taniguchi; Dimitris Kioussis



CD83 Expression Influences CD4 + T Cell Development in the Thymus  

Microsoft Academic Search

T lymphocyte selection and lineage commitment in the thymus requires multiple signals. Herein, CD4+ T cell generation required engagement of CD83, a surface molecule expressed by thymic epithelial and dendritic cells. CD83-deficient (CD83?\\/?) mice had a specific block in CD4+ single-positive thymocyte development without increased CD4+CD8+ double- or CD8+ single-positive thymocytes. This resulted in a selective 75%–90% reduction in peripheral

Yoko Fujimoto; LiLi Tu; Ann S. Miller; Cheryl Bock; Manabu Fujimoto; Carolyn Doyle; Douglas A. Steeber; Thomas F. Tedder



T cell- but not tumor cell-produced TGF-?1 promotes the development of spontaneous mammary cancer  

PubMed Central

During their development, tumors acquire multiple capabilities that enable them to proliferate, disseminate and evade immunosurveillance. A putative mechanism is through the production of the cytokine TGF-?1. We showed in our recent studies that T cell-produced TGF-?1 inhibits antitumor T cell responses to foster tumor growth raising the question of the precise function of TGF-?1 produced by tumor cells in tumor development. Here, using a transgenic model of mammary cancer, we report that deletion of TGF-?1 from tumor cells did not protect mice from tumor development. However, ablation of TGF-?1 from T cells significantly inhibited mammary tumor growth. Additionally, absence of TGF-?1 in T cells prevented tumors from advancing to higher pathological grades and further suppressed secondary tumor development in the lungs. These findings reveal T cells but not tumor cells as a critical source of TGF-?1 that promotes tumor development.

Sarkar, Abira; Donkor, Moses K.; Li, Ming O.



Intrathymic IL-7: The where, when, and why of IL-7 signaling during T cell development  

PubMed Central

The thymus is the birthplace of all T lineage cells. But the thymus is also a cradle as it provides the environment for further maturation and differentiation of immature thymocytes. While many factors contribute to make the thymus a unique place for T cell development, here we review the essential role of intrathymic interleukin-7 (IL-7). In the absence of IL-7 signaling, survival, proliferation and differentiation of immature thymocytes are all severely impaired. Consequently, IL-7 is critical to nurture and guide T precursor cells through the diverse steps of thymic maturation. Interestingly, even as IL-7 signaling is such a critical factor, IL-7 signaling must be also actively suppressed during specific stages of T cell differentiation. These contradictory observations are puzzling but can be satisfactorily explained when understanding the developmental context of IL-7 signaling. In this regard, here we will discuss the spatiotemporal expression of intrathymic IL-7 and address the stage-specific effects of IL-7 signaling in developing thymocytes. Specifically, we will review other facets of intrathymic IL-7 beyond its role as a pro-survival factor and so clarify and reaffirm the unique role of IL-7 as a prime factor in T cell development and differentiation.

Hong, Changwan; Luckey, Megan; Park, Jung-Hyun



A Recurrent Stop-Codon Mutation in Succinate Dehydrogenase Subunit B Gene in Normal Peripheral Blood and Childhood T-Cell Acute Leukemia  

Microsoft Academic Search

BackgroundSomatic cytidine mutations in normal mammalian nuclear genes occur during antibody diversification in B lymphocytes and generate an isoform of apolipoprotein B in intestinal cells by RNA editing. Here, I describe that succinate dehydrogenase (SDH; mitochondrial complex II) subunit B gene (SDHB) is somatically mutated at a cytidine residue in normal peripheral blood mononuclear cells (PBMCs) and T-cell acute leukemia.

Bora E. Baysal; Stefan Maas



Myelin Oligodendrocyte Glycoprotein-specific T Cell Receptor Transgenic Mice Develop Spontaneous Autoimmune Optic Neuritis  

PubMed Central

Multiple sclerosis (MS) is considered to be an autoimmune disease of the central nervous system (CNS) that in many patients first presents clinically as optic neuritis. The relationship of optic neuritis to MS is not well understood. We have generated novel T cell receptor (TCR) transgenic mice specific for myelin oligodendrocyte glycoprotein (MOG). MOG-specific transgenic T cells are not deleted nor tolerized and are functionally competent. A large proportion (>30%) of MOG-specific TCR transgenic mice spontaneously develop isolated optic neuritis without any clinical nor histological evidence of experimental autoimmune encephalomyelitis (EAE). Optic neuritis without EAE could also be induced in these mice by sensitization with suboptimal doses of MOG. The predilection of these mice to develop optic neuritis is associated with higher expression of MOG in the optic nerve than in the spinal cord. These results demonstrate that clinical manifestations of CNS autoimmune disease will vary depending on the identity of the target autoantigen and that MOG-specific T cell responses are involved in the genesis of isolated optic neuritis.

Bettelli, Estelle; Pagany, Maria; Weiner, Howard L.; Linington, Christopher; Sobel, Raymond A.; Kuchroo, Vijay K.



Normalization of Tumor Microenvironment by Neem Leaf Glycoprotein Potentiates Effector T Cell Functions and Therapeutically Intervenes in the Growth of Mouse Sarcoma  

PubMed Central

We have observed restriction of the murine sarcoma growth by therapeutic intervention of neem leaf glycoprotein (NLGP). In order to evaluate the mechanism of tumor growth restriction, here, we have analyzed tumor microenvironment (TME) from sarcoma bearing mice with NLGP therapy (NLGP-TME, in comparison to PBS-TME). Analysis of cytokine milieu within TME revealed IL-10, TGF?, IL-6 rich type 2 characters was switched to type 1 microenvironment with dominance of IFN? secretion within NLGP-TME. Proportion of CD8+ T cells was increased within NLGP-TME and these T cells were protected from TME-induced anergy by NLGP, as indicated by higher expression of pNFAT and inhibit related downstream signaling. Moreover, low expression of FasR+ cells within CD8+ T cell population denotes prevention from activation induced cell death. Using CFSE as a probe, better migration of T cells was noted within TME from NLGP treated mice than PBS cohort. CD8+ T cells isolated from NLGP-TME exhibited greater cytotoxicity to sarcoma cells in vitro and these cells show higher expression of cytotoxicity related molecules, perforin and granzyme B. Adoptive transfer of NLGP-TME exposed T cells, but not PBS-TME exposed cells in mice, is able to significantly inhibit the growth of sarcoma in vivo. Such tumor growth inhibition by NLGP-TME exposed T cells was not observed when mice were depleted for CD8+ T cells. Accumulated evidences strongly suggest NLGP mediated normalization of TME allows T cells to perform optimally to inhibit the tumor growth.

Barik, Subhasis; Banerjee, Saptak; Mallick, Atanu; Goswami, Kuntal Kanti; Roy, Soumyabrata; Bose, Anamika; Baral, Rathindranath



Normalization of tumor microenvironment by neem leaf glycoprotein potentiates effector T cell functions and therapeutically intervenes in the growth of mouse sarcoma.  


We have observed restriction of the murine sarcoma growth by therapeutic intervention of neem leaf glycoprotein (NLGP). In order to evaluate the mechanism of tumor growth restriction, here, we have analyzed tumor microenvironment (TME) from sarcoma bearing mice with NLGP therapy (NLGP-TME, in comparison to PBS-TME). Analysis of cytokine milieu within TME revealed IL-10, TGF?, IL-6 rich type 2 characters was switched to type 1 microenvironment with dominance of IFN? secretion within NLGP-TME. Proportion of CD8(+) T cells was increased within NLGP-TME and these T cells were protected from TME-induced anergy by NLGP, as indicated by higher expression of pNFAT and inhibit related downstream signaling. Moreover, low expression of FasR(+) cells within CD8(+) T cell population denotes prevention from activation induced cell death. Using CFSE as a probe, better migration of T cells was noted within TME from NLGP treated mice than PBS cohort. CD8(+) T cells isolated from NLGP-TME exhibited greater cytotoxicity to sarcoma cells in vitro and these cells show higher expression of cytotoxicity related molecules, perforin and granzyme B. Adoptive transfer of NLGP-TME exposed T cells, but not PBS-TME exposed cells in mice, is able to significantly inhibit the growth of sarcoma in vivo. Such tumor growth inhibition by NLGP-TME exposed T cells was not observed when mice were depleted for CD8(+) T cells. Accumulated evidences strongly suggest NLGP mediated normalization of TME allows T cells to perform optimally to inhibit the tumor growth. PMID:23785504

Barik, Subhasis; Banerjee, Saptak; Mallick, Atanu; Goswami, Kuntal Kanti; Roy, Soumyabrata; Bose, Anamika; Baral, Rathindranath



Development and dynamics of robust T-cell responses to CML under imatinib treatment  

PubMed Central

Novel molecular targeted therapies, such as imatinib for chronic myelogenous leukemia (CML), represent the first agents that inhibit cancer cells more than other dividing cells, such as immune cells. We hypothesize that imatinib may create a window in which the immune response is partially restored while apoptotic leukemic cells are present, thus rendering leukemic cells immunogenic as patients enter remission. To detect and quantify antileukemia immune responses in an antigen-unbiased way, we used cryopreserved autologous pretreatment blood samples (representing predominantly leukemic cells) as stimulators to detect antileukemia T-cell responses in CML patients in remission on imatinib. We studied patients over time to address the dynamics of such responses. Our data show that antileukemia T-cell responses develop in the majority of CML patients (9 of 14) in remission and that CD4+ T cells producing tumor necrosis factor-? (median 17.6%) represent the major response over interferon-?. This confirms the immune system's ability to respond to leukemia under certain conditions. Such responses may be further amplified as a potential therapy that synergizes with imatinib for improved control of CML.

Chen, Christiane I-U.; Maecker, Holden T.



Control of early stages in invariant natural killer T-cell development.  


Natural killer T (NKT) cells develop in the thymus from the same precursors as conventional CD4(+) and CD8(+) ?? T cells, CD4(+) ?CD8(+) double-positive cells. In contrast to conventional ??T cells, which are selected by MHC-peptide complexes presented by thymic epithelial cells, invariant NKT cells are selected by lipid antigens presented by the non-polymorphic, MHC I-like molecule CD1d, present on the surface of other double-positive thymocytes, and require additional signals from the signalling lymphocytic-activation molecule (SLAM) family of receptors. In this review, we provide a discussion of recent findings that have modified our understanding of the NKT cell developmental programme, with an emphasis on events that affect the early stages of this process. This includes factors that control double-positive thymocyte lifespan, and therefore the ability to generate the canonical V? rearrangements that characterize this lineage, as well as the signal transduction pathways engaged downstream of the T-cell receptor and SLAM molecules. PMID:21718314

Hu, Taishan; Gimferrer, Idoia; Alberola-Ila, José



MicroRNA-155 promotes autoimmune inflammation by enhancing inflammatory T cell development  

PubMed Central

Summary Mammalian non-coding micro RNAs (miRNAs) are a class of gene regulators that have been linked to immune system function. Here, we have investigated the role of miR-155 during an autoimmune inflammatory disease. Consistent with a positive role for miR-155 in mediating inflammatory responses, Mir155?/? mice were highly resistant to experimental autoimmune encephalomyelitis (EAE). miR-155 functions in the hematopoietic compartment to promote the development of inflammatory T cells including the T helper 17 (Th17) cell and Th1 cell subsets. Furthermore, the major contribution of miR-155 to EAE was CD4+ T cell intrinsic, whereas miR-155 was also required for optimum dendritic cell production of cytokines that promoted Th17 cell formation. Our study shows that one aspect of miR-155 function is the promotion of T cell-dependent tissue inflammation, suggesting that miR-155 might be a promising therapeutic target for the treatment of autoimmune disorders.

O'Connell, Ryan M.; Kahn, Daniel; Gibson, William S.J.; Round, June L.; Scholz, Rebecca L.; Chaudhuri, Aadel A.; Kahn, Melissa E.; Rao, Dinesh S.; Baltimore, David



Murine CD4 T Cells Produce a New Form of TGF-? as Measured by a Newly Developed TGF-? Bioassay  

PubMed Central

Background It is generally assumed that T cells do not produce active TGF-? since active TGF-? as measured in supernatants by ELISA without acidification is usually not detectable. However, it is possible that active TGF-? from T cells may take a special form which is not detectable by ELISA. Methodology/Principal Findings We constructed a TGF-? bioassay which can detect both soluble and membrane-bound forms of TGF-? from T cells. For this bioassay, 293T cells were transduced with (caga)12 Smad binding element-luciferase along with CD32 (Fc receptor) and CD86. The resulting cells act as artificial antigen presenting cells in the presence of anti-CD3 and produce luciferase in response to biologically active TGF-?. We co-cultured pre-activated murine CD4+CD25? T cells or CD4+CD25+ T cells with the 293T-caga-Luc-CD32-CD86 reporter cells in the presence of anti-CD3 and IL-2. CD4+CD25? T cells induced higher luciferase in the reporter cells than CD4+CD25+ T cells. This T cell-produced TGF-? is in a soluble form since T cell culture supernatants contained the TGF-? activity. The TGF-? activity was neutralized with an anti-mouse LAP mAb or an anti-latent TGF-?/pro-TGF-? mAb, but not with anti-active TGF-? Abs. An anti-mouse LAP mAb removed virtually all acid activatable latent TGF-? from the T cell culture supernatant, but not the ability to induce TGF-? signaling in the reporter cells. The induction of TGF-? signaling by T cell culture supernatants was cell type-specific. Conclusions/Significance A newly developed 293T-caga-Luc-CD32-CD86 reporter cell bioassay demonstrated that murine CD4 T cells produce an unconventional form of TGF-? which can induce TGF-? signaling. This new form of TGF-? contains LAP as a component. Our finding of a new form of T cell-produced TGF-? and the newly developed TGF-? bioassay system will provide a new avenue to investigate T cell function of the immune system.

Oida, Takatoku; Weiner, Howard L.



Epidermal T Cells and Wound Healing  

PubMed Central

The murine epidermis contains resident T cells that express a canonical ?? TCR. These cells arise from fetal thymic precursors and use a TCR that is restricted to the skin in adult animals. These cells assume a dendritic morphology in normal skin and constitutively produce low levels of cytokines that contribute to epidermal homeostasis. When skin is wounded, an unknown antigen is expressed on damaged keratinocytes. Neighboring ?? T cells then round up and contribute to wound healing by local production of epithelial growth factors and inflammatory cytokines. In the absence of skin ?? T cells, wound healing is impaired. Similarly, epidermal T cells from patients with healing wounds are activated and secreting growth factors. Patients with non-healing wounds have a defective epidermal T cell response. Information gained on the role of epidermal-resident T cells in the mouse may provide information for development of new therapeutic approaches to wound healing.

Havran, Wendy L.; Jameson, Julie M.



Clonal deletion of self-reactive T cells at the early stage of T cell development in thymus of radiation bone marrow chimeras  

SciTech Connect

Sequential appearance of T cell subpopulations occurs in the thymocytes of irradiated C3H/He mice (H-2k, Mls-1b2a, Thy-1.2) after transplantation with bone marrow cells of AKR/J mice (H-2k, Mls-1a2b, Thy-1.1) (AKR----C3H chimeras). The donor-derived thymocytes of AKR----C3H chimeras on day 14 after bone marrow transplantation (BMT) contained a large number of blastlike CD4+CD8+ cells which represent relatively immature thymocytes, whereas those on day 21 after BMT consisted of small sized CD4+,CD8+ cells which represent a great part in normal thymocytes. To define the developmental stage at which clonal deletion of self-reactive T cells occurs in adult thymus, we followed the fate of V beta 6- or V beta 11-bearing T cells in the donor-derived thymocytes at the early stage of AKR----C3H chimeras. Mature thymocytes expressing high intensity of V beta 6 or V beta 11, which are involved in recognition of Mls-1a or MHC I-E gene products, respectively, were deleted from the donor-derived thymocytes on day 21. Immature thymocytes expressing low intensity of V beta 6 in CD3low thymocyte fraction decreased in proportion, whereas those expressing low intensity of V beta 11 rather increased in proportion in the donor-derived thymocytes of AKR----C3H chimeras from day 14 to day 21 after BMT. These results suggest that the clonal deletion of V beta 6-positive cells occurs just at the stage of immature CD3lowCD4+CD8+ cells, whereas the clonal deletion of V beta 11-positive cells may begin at the transitional stage from CD3lowCD4+CD8+ cells to CD3high single positive cells. Timing of negative selection of thymocytes may vary in distinct T cells capable of recognizing different self-Ag.

Matsuzaki, G.; Yoshikai, Y.; Ogimoto, M.; Kishihara, K.; Nomoto, K. (Kyushu Univ., Fukuoka (Japan))



PD-L1 regulates the development, maintenance, and function of induced regulatory T cells  

PubMed Central

Both the programmed death (PD) 1–PD-ligand (PD-L) pathway and regulatory T (T reg) cells are instrumental to the maintenance of peripheral tolerance. We demonstrate that PD-L1 has a pivotal role in regulating induced T reg (iT reg) cell development and sustaining iT reg cell function. PD-L1?/? antigen-presenting cells minimally convert naive CD4 T cells to iT reg cells, showing the essential role of PD-L1 for iT reg cell induction. PD-L1–coated beads induce iT reg cells in vitro, indicating that PD-L1 itself regulates iT reg cell development. Furthermore, PD-L1 enhances and sustains Foxp3 expression and the suppressive function of iT reg cells. The obligatory role for PD-L1 in controlling iT reg cell development and function in vivo is illustrated by a marked reduction in iT reg cell conversion and rapid onset of a fatal inflammatory phenotype in PD-L1?/?PD-L2?/? Rag?/? recipients of naive CD4 T cells. PD-L1 iT reg cell development is mediated through the down-regulation of phospho-Akt, mTOR, S6, and ERK2 and concomitant with the up-regulation of PTEN, all key signaling molecules which are critical for iT reg cell development. Thus, PD-L1 can inhibit T cell responses by promoting both the induction and maintenance of iT reg cells. These studies define a novel mechanism for iT reg cell development and function, as well as a new strategy for controlling T reg cell plasticity.

Francisco, Loise M.; Salinas, Victor H.; Brown, Keturah E.; Vanguri, Vijay K.; Freeman, Gordon J.; Kuchroo, Vijay K.



Melanoma cells and normal melanocytes share antigens recognized by HLA- A2-restricted cytotoxic T cell clones from melanoma patients  

PubMed Central

HLA-A2-restricted, CD3+, CD8+, alpha/beta+ cytotoxic T cell (CTL) clones were isolated from peripheral blood (PBL) or tumor infiltrating lymphocytes (TIL) of two HLA-A2+ melanoma patients (9742 and 5810), to evaluate the possible recognition of autologous melanoma and of allogeneic HLA-A2-matched normal melanocytes. These CTL clones lysed not only fresh and cultured autologous melanoma cells, but also allogeneic HLA-A2+, but not HLA-A2-, normal melanocytes. The lysis of autologous neoplastic cells and of melanocytes could be inhibited by an anti-HLA-A2 monoclonal antibody (mAb). Lysis of the normal melanocytes was not dependent on the presence of human or fetal calf serum in the culture medium. HLA-A2-restricted CTL clones recognized not only proliferating melanocytes cultured in complete melanocyte medium, but also melanocytes made quiescent by culture for up to 6 d in a basal medium devoid of exogenous factors such as phorbol ester (O- tetradecanoyl phorbol 13-acetate [TPA]), epidermal growth factor, insulin, and pituitary extracts. Analysis of specificity of four CTL clones (A75, A83, A94, and 119) from patient 9742, performed on a panel of 39 targets, indicated that the three HLA-A2-restricted CTL (A75, A83, and A94) lysed all but one of nine allogeneic melanomas expressing the HLA-A2 molecule with no reactivity on nine HLA-A2- allogeneic melanomas. Only a few instances of borderline reactivity were seen by the same effectors on 21 targets of nonmelanocyte lineage, including 12 carcinomas of different histology, four Epstein-Barr virus-transformed B cells (lymphoblastoid cell lines [LCL]), including the autologous LCL, four lines of normal fibroblasts, and normal kidney cells. Lack of reactivity on allogeneic targets of nonmelanocyte lineage occurred in spite of expression of HLA-A2 on 14 of these targets as determined by conventional tissue typing and cytofluorimetric analysis with four different anti-HLA-A2 mAb. These data indicate that tissue-related antigens can be expressed on normal and neoplastic cells of the melanocyte lineage and can be recognized in association with HLA-A2 by CTL clones from melanoma patients.



In vivo expression of interleukin-8, and regulated on activation, normal, T-cell expressed, and secreted, by human germinal centre B lymphocytes  

PubMed Central

T-cell homing within germinal centres (GCs) is required for humoral B-cell responses. However, the mechanisms implicated in the recruitment of T cells into the GC are not completely understood. Here we show, by immunohistology, and Northern and Western blots, that in vivo human GC B lymphocytes can express CxC and CC chemokines. Moreover, B-cell subset-specific experiments reveal that interleukin (IL)-8 and regulated on activation, normal, T-cell expressed, and secreted (RANTES) are predominantly expressed by GC centroblast and centrocytes, suggesting that chemokine expression is essential at stages in which B-lymphocytes engage in active antigen-dependent interactions with T lymphocytes. In keeping with this hypothesis, we show that the T cells recruited into the GC correlatively express the receptors for IL-8 and RANTES. We propose that chemokine expression is a key B-cell function that facilitates T-lymphocyte recruitment into the GCs and supports cognate B-cell : T-cell encounters. Moreover, our data are consistent with the impaired homing of T cells to secondary lymphoid organs in mice that are either deficient in CC and CxC chemokines or their receptors.

Sims-Mourtada, Jennifer C; Guzman-Rojas, Liliana; Rangel, Roberto; Nghiem, Dat X; Ullrich, Stephen E; Guret, Christiane; Cain, Kelly; Martinez-Valdez, Hector



Human gamma delta T cells: candidates for the development of immunotherapeutic strategies.  


A numerically small subset of human T lymphocytes expresses a gamma delta T cell receptor (TCR). These gamma delta T cells share certain effector functions with alpha beta T cells as well as with NK cells and NKT cells. The major peripheral blood gamma delta T cell subset in healthy adults expresses a Vgamma9Vdelta2 TCR, which recognizes small phosphorylated metabolites referred to as phosphoantigens. Vdelta1 gamma delta T cells mainly occur in the intestine. They recognize the stress-induced MICA/B and CD1c. Furthermore, gamma delta T cells express a variety of NK cell and pattern-recognition receptors which are responsible for the "fine-tuning" of effector functions. In recent years, gamma delta T cells start to emerge as a rewarding target for immunotherapeutic strategies against viral infections and cancer. A better understanding of factors that modulate gamma gamma delta T cell function will further eluminate the potential of these cells. PMID:17695246

Beetz, Susann; Marischen, Lothar; Kabelitz, Dieter; Wesch, Daniela



KLF13 influences multiple stages of both B and T cell development.  


The Kruppel-like factor, KLF13, is a member of a family of transcription factors shown to be involved in haematopoietic development. Here we show that KLF13 is involved in the development of B and T cells at multiple stages. Expression of KLF13 in the thymus was maximal in the DP population and in KLF13(-/-) deficient mice there was an accumulation of DP thymocytes and reduction of CD4(+)SP cells. Cell-surface expression of CD3(high), CD8, CD5 and HSA were altered on KLF13(-/-) DP cells, consistent with a defect in TCR signalling and at the DP to SP transition in KLF13(-/-) mice. KLF13 is also expressed in peripheral T-cells and peripheral T cell activation was impaired in KLF13(-/-) mice. Analysis of early B cell development in the bone marrow (BM) revealed a partial arrest of B cells at the transition from CD43(+) to CD43(-) pre-B cell, a transition that requires signalling through the pre-BCR. The proportion of IgM(+)/IgD(+) mature B cells was also increased in the BM of the KLF13(-/-) mice. This finding is consistent with a reduction in the strength of BCR signal or an accumulation of recirculating B cells from the periphery. Analysis of splenocytes isolated from KLF13(-/-) mice revealed an increase in the expression of CD21 and CD23 on B220(+) B cells, demonstrating a negative regulatory role for KLF13 in co-regulation of expression of CD21 and CD23. Thus KLF13 is involved at multiple different checkpoints in development that require signalling through the TCR, pre-BCR or mature BCR. PMID:18604172

Outram, Susan V; Gordon, Adele R; Hager-Theodorides, Ariadne L; Metcalfe, James; Crompton, Tessa; Kemp, Paul



Ezrin Is Highly Expressed in Early Thymocytes, but Dispensable for T Cell Development in Mice  

PubMed Central

Background Ezrin/radixin/moesin (ERM) proteins are highly homologous proteins that function to link cargo molecules to the actin cytoskeleton. Ezrin and moesin are both expressed in mature lymphocytes, where they play overlapping roles in cell signaling and polarity, but their role in lymphoid development has not been explored. Methodology/Principal Findings We characterized ERM protein expression in lymphoid tissues and analyzed the requirement for ezrin expression in lymphoid development. In wildtype mice, we found that most cells in the spleen and thymus express both ezrin and moesin, but little radixin. ERM protein expression in the thymus was differentially regulated, such that ezrin expression was highest in immature thymocytes and diminished during T cell development. In contrast, moesin expression was low in early thymocytes and upregulated during T cell development. Mice bearing a germline deletion of ezrin exhibited profound defects in the size and cellularity of the spleen and thymus, abnormal thymic architecture, diminished hematopoiesis, and increased proportions of granulocytic precursors. Further analysis using fetal liver chimeras and thymic transplants showed that ezrin expression is dispensable in hematopoietic and stromal lineages, and that most of the defects in lymphoid development in ezrin?/? mice likely arise as a consequence of nutritional stress. Conclusions/Significance We conclude that despite high expression in lymphoid precursor cells, ezrin is dispensable for lymphoid development, most likely due to redundancy with moesin.

Shaffer, Meredith H.; Huang, Yanping; Corbo, Evann; Wu, Gregory F.; Velez, Marielena; Choi, John K.; Saotome, Ichiko; Cannon, Judy L.; McClatchey, Andrea I.; Sperling, Anne I.; Maltzman, Jonathan S.; Oliver, Paula M.; Bhandoola, Avinash; Laufer, Terri M.; Burkhardt, Janis K.



Ionizing radiation and autoimmunity: Induction of autoimmune disease in mice by high dose fractionated total lymphoid irradiation and its prevention by inoculating normal T cells  

SciTech Connect

Ionizing radiation can functionally alter the immune system and break self-tolerance. High dose (42.5 Gy), fractionated (2.5 Gy 17 times) total lymphoid irradiation (TLI) on mice caused various organ-specific autoimmune diseases, such as gastritis, thyroiditis, and orchitis, depending on the radiation dosages, the extent of lymphoid irradiation, and the genetic background of the mouse strains. Radiation-induced tissue damage is not the primary cause of the autoimmune disease because irradiation of the target organs alone failed to elicit the autoimmunity and shielding of the organs from irradiation was unable to prevent it. In contrast, irradiation of both the thymus and the peripheral lymphoid organs/tissues was required for efficient induction of autoimmune disease by TLI. TLI eliminated the majority of mature thymocytes and the peripheral T cells for 1 mo, and inoculation of spleen cell, thymocyte, or bone marrow cell suspensions (prepared from syngeneic nonirradiated mice) within 2 wk after TLI effectively prevented the autoimmune development. Depletion of T cells from the inocula abrogated the preventive activity. CD4[sup +] T cells mediated the autoimmune prevention but CD8[sup +] T cells did not. CD4[sup +] T cells also appeared to mediate the TLI-induced autoimmune disease because CD4[sup +] T cells from disease-bearing TLI mice adoptively transferred the autoimmune disease to syngeneic naive mice. Taken together, these results indicate that high dose, fractionated ionizing radiation on the lymphoid organs/tissues can cause autoimmune disease by affecting the T cell immune system, rather than the target self-Ags, presumably by altering T cell-dependent control of self-reactive T cells. 62 refs., 9 figs., 2 tabs.

Sakaguchi, N.; Sakaguchi, S. (Stanford Univ. School of Medicine, CA (United States) Scripps Research Institute, La Jolla, CA (United States) PRESTO, JRDC, Institute of Phical and Chemical Research, Tsukuba, Ibaraki (Japan)); Miyai, K. (Univ. of California, San Diego, LA Jolla, CA (United States))



Activated T cells induce expression of B7/BB1 on normal or leukemic B cells through a CD40-dependent signal  

PubMed Central

Cognate interactions between antigen-presenting B and T cells play crucial roles in immunologic responses. T cells that have been activated via the crosslinking of CD3 are able to induce B cell proliferation and immunoglobulin secretion in a major histocompatibility complex-unrestricted and contact-dependent manner. We find that such activated human CD4+ T cells, but not control Ig- treated T cells, may induce normal or leukemic B cells to express B7/BB1 and significantly higher levels of CD54 intercellular adhesion molecule 1 via a process that also requires direct cell-cell contact. To discern what cell surface molecule(s) may be responsible for signalling B cells to express B7/BB1, we added various monoclonal antibodies (mAbs) specific for T or B cell accessory molecules or control mAbs to cocultures of alpha-CD3-activated T cells and resting B cells. We find that only alpha-CD40 mAbs can significantly inhibit the increased expression of B7/BB1, suggesting that the ligand for CD40 expressed on activated T cells may be an important inducer of B7/BB1 expression. Subsequent experiments in fact demonstrate that alpha-CD40 mAbs, but not control mAbs, induce changes in B cell phenotype similar to those induced by activated T cells when the mAbs are presented on Fc gamma RII (CDw32)-expressing L cells. These phenotypic changes have significant effects on B cell function. Whereas chronic lymphocytic leukemia (CLL) B cells normally are very poor stimulators in allogeneic mixed lymphocyte reactions (MLRs), CLL-B cells preactivated via CD40 crosslinking are significantly better presenters of alloantigen, affecting up to 30-fold-greater stimulation of T cell proliferation than that induced by control treated or nontreated CLL-B cells. Similarly, the MLR of T cells stimulated by allogeneic nonleukemic B cells can be enhanced significantly if the stimulator B cells are preactivated via CD40 crosslinking. The enhanced MLR generated by such preactivated B cells may be inhibited by blocking B7/BB1-CD28 interaction with CTLA4Ig. These studies demonstrate a novel, CD40- dependent pathway for inducing B cell expression of B7/BB1 and enhancing B cell antigen-presenting cell activity that can be initiated via cell-cell contact with alpha-CD3-stimulated CD4+ T cells.



Clonality, activated antigen-specific CD8(+) T cells, and development of autoimmune cholangitis in dnTGF?RII mice.  


There are several murine models described with features similar to human primary biliary cirrhosis (PBC). Among these models, the one which has the closest serologic features to PBC is a mouse with a T-cell-restricted expression of the dominant negative transforming growth factor ? receptor type II (dnTGF?RII). Our work has demonstrated that CD8(+) T cells from dnTGF?RII mice transfer autoimmune cholangitis to Rag1(-/-) recipients. However, it remained unclear whether the autoimmune cholangitis was secondary to an intrinsic function within CD8(+) T cells or due to the abnormal TGF?R environment within which CD8(+) T cells were generated. To address this mechanistic issue, we used our dnTGF?RII, OT-I/Rag1(-/-) , OT-II/Rag1(-/-) mice and in addition generated OT-I/dnTGF?RII/Rag1(-/-) , and OT-II/dnTGF?RII/Rag1(-/-) mice in which the entire T-cell repertoire was replaced with ovalbumin (OVA)-specific CD8(+) or CD4(+) T cells, respectively. Importantly, neither the parental OT-I/dnTGF?RII/Rag1(-/-) mice and/or OT-II/dnTGF?RII/Rag1(-/-) mice developed cholangitis. However, adoptive transfer demonstrated that only transfer of CD8(+) T cells from dnTGF?RII mice but not CD8(+) T cells from OT-I/Rag1(-/-) mice or from OT-I/dnTGF?RII/Rag1(-/-) mice transferred disease. These data were not secondary to an absence of CD4(+) T cell help since a combination of CD8(+) T cells from OT-I/dnTGF?RII/Rag1(-/-) and CD4(+) T cells from OT II/dnTGF?RII/Rag1(-/-) or CD8(+) T cells from OT-I/dnTGF?RII/Rag1(-/-) with CD4(+) T cells from OT-II/Rag1(-/-) mice failed to transfer disease. Conclusion: Defective TGF?RII signaling, in addition to clonal CD8(+) T cells that target biliary cells, are required for induction of autoimmune cholangitis. (Hepatology 2013;53:1094-1104). PMID:23532950

Kawata, Kazuhito; Yang, Guo-Xiang; Ando, Yugo; Tanaka, Hajime; Zhang, Weici; Kobayashi, Yoshimasa; Tsuneyama, Koichi; Leung, Patrick S C; Lian, Zhe-Xiong; Ridgway, William M; Ansari, Aftab A; He, Xiao-Song; Gershwin, M Eric



Diacylglycerol Kinases: Regulated Controllers of T Cell Activation, Function, and Development  

PubMed Central

Diacylglycerol kinases (DGKs) are a diverse family of enzymes that catalyze the conversion of diacylglycerol (DAG), a crucial second messenger of receptor-mediated signaling, to phosphatidic acid (PA). Both DAG and PA are bioactive molecules that regulate a wide set of intracellular signaling proteins involved in innate and adaptive immunity. Clear evidence points to a critical role for DGKs in modulating T cell activation, function, and development. More recently, studies have elucidated factors that control DGK function, suggesting an added complexity to how DGKs act during signaling. This review summarizes the available knowledge of the function and regulation of DGK isoforms in signal transduction with a particular focus on T lymphocytes.

Joshi, Rohan P.; Koretzky, Gary A.



Development of Tumor-Reactive T Cells After Nonmyeloablative Allogeneic Hematopoietic Stem Cell Transplant for Chronic Lymphocytic Leukemia  

PubMed Central

Purpose Allogeneic NM-HSCT can result in durable remission of chronic lymphocytic leukemia (CLL). It is thought that the efficacy of NM-HSCT is mediated by recognition of tumor cells by T cells in the donor stem cell graft. We evaluated the development of cytotoxic T lymphocytes (CTL) specific for CLL after NM-HSCT to determine if their presence correlated with antitumor efficacy. Experimental Design Peripheral blood mononuclear cells obtained from twelve transplant recipients at intervals after NM-HSCT were stimulated in vitro with CLL cells. Polyclonal T cell lines and CD8+ T cell clones were derived from these cultures and evaluated for lysis of donor and recipient target cells including CLL. The presence and specificity of responses was correlated with clinical outcomes. Results Eight of the 12 patients achieved remission or a major antitumor response and all eight developed CD8+ and CD4+ T cells specific for antigens expressed by CLL. A clonal analysis of the CD8+ T cell response identified T cells specific for multiple minor histocompatibility (H) antigens expressed on CLL in six of the responding patients. A significant fraction of the CD8+ T cell response in some patients was also directed against non-shared tumor-specific antigens. By contrast, CLL-reactive T cells were not detected in the four patients who had persistent CLL after NM-HSCT, despite the development of GVHD. Conclusions The development of a diverse T cell response specific for minor H and tumor-associated antigens expressed by CLL predicts an effective GVL response after NM-HSCT.

Nishida, Tetsuya; Hudecek, Michael; Kostic, Ana; Bleakley, Marie; Warren, Edus H.; Maloney, David; Storb, Rainer; Riddell, Stanley R.



Cell-Intrinsic Role for NF-kappa B-Inducing Kinase in Peripheral Maintenance but Not Thymic Development of Foxp3(+) Regulatory T Cells in Mice.  


NF-?B inducing kinase (NIK, MAP3K14) is a key signaling molecule in non-canonical NF-?B activation, and NIK deficient mice have been instrumental in deciphering the immunologic role of this pathway. Global ablation of NIK prevents lymph node development, impairs thymic stromal development, and drastically reduces B cells. Despite altered thymic selection, T cell numbers are near normal in NIK deficient mice. The exception is CD4(+) regulatory T cells (Tregs), which are reduced in the thymus and periphery. Defects in thymic stroma are known to contribute to impaired Treg generation, but whether NIK also plays a cell intrinsic role in Tregs is unknown. Here, we compared intact mice with single and mixed BM chimeric mice to assess the intrinsic role of NIK in Treg generation and maintenance. We found that while NIK expression in stromal cells suffices for normal thymic Treg development, NIK is required cell-intrinsically to maintain peripheral Tregs. In addition, we unexpectedly discovered a cell-intrinsic role for NIK in memory phenotype conventional T cells that is masked in intact mice, but revealed in BM chimeras. These results demonstrate a novel role for NIK in peripheral regulatory and memory phenotype T cell homeostasis. PMID:24073289

Murray, Susan E



Cell-Intrinsic Role for NF-kappa B-Inducing Kinase in Peripheral Maintenance but Not Thymic Development of Foxp3+ Regulatory T Cells in Mice  

PubMed Central

NF-?B inducing kinase (NIK, MAP3K14) is a key signaling molecule in non-canonical NF-?B activation, and NIK deficient mice have been instrumental in deciphering the immunologic role of this pathway. Global ablation of NIK prevents lymph node development, impairs thymic stromal development, and drastically reduces B cells. Despite altered thymic selection, T cell numbers are near normal in NIK deficient mice. The exception is CD4+ regulatory T cells (Tregs), which are reduced in the thymus and periphery. Defects in thymic stroma are known to contribute to impaired Treg generation, but whether NIK also plays a cell intrinsic role in Tregs is unknown. Here, we compared intact mice with single and mixed BM chimeric mice to assess the intrinsic role of NIK in Treg generation and maintenance. We found that while NIK expression in stromal cells suffices for normal thymic Treg development, NIK is required cell-intrinsically to maintain peripheral Tregs. In addition, we unexpectedly discovered a cell-intrinsic role for NIK in memory phenotype conventional T cells that is masked in intact mice, but revealed in BM chimeras. These results demonstrate a novel role for NIK in peripheral regulatory and memory phenotype T cell homeostasis.

Murray, Susan E.



Enforced expression of Lin28b leads to impaired T-cell development, release of inflammatory cytokines, and peripheral T-cell lymphoma  

PubMed Central

LIN28A and LIN28B, the mammalian homologs of lin-28, are implicated in malignant transformation in part because of their ability to promote degradation of the let-7 family of miRs. In the present study, we show that overexpression of Lin28b in vivo leads to an aggressive peripheral T-cell lymphoma (PTCL) characterized by widespread infiltration of parenchymal organs with malignant CD4+ cells. Similar to patients with PTCL, Lin28b-transgenic mice show signs of inflammation such as eosinophilia, increased C-reactive protein, release of inflammatory cytokines, and pleural effusion. The PTCLs that develop in Lin28b mice are derived from activated T cells and show decreased let-7 expression, increased Il6 expression, activation of NF-?B, and infiltration of B cells, all resulting in an inflammatory microenvironment. In addition, LIN28B is overexpressed 7.5-fold in PTCL patient samples compared with activated CD4+ cells. The results of the present study demonstrate for the first time that Lin28b can transform primary cells in vivo, identify a previously unsuspected link between Lin28b and PTCL, and provide a unique animal model for the study of PTCL biology and therapy.

Beachy, Sarah H.; Onozawa, Masahiro; Chung, Yang Jo; Slape, Chris; Bilke, Sven; Francis, Princy; Pineda, Marbin; Walker, Robert L.; Meltzer, Paul



A retinoic acid-dependent checkpoint in the development of CD4+ T cell-mediated immunity  

PubMed Central

It is known that vitamin A and its metabolite, retinoic acid (RA), are essential for host defense. However, the mechanisms for how RA controls inflammation are incompletely understood. The findings presented in this study show that RA signaling occurs concurrent with the development of inflammation. In models of vaccination and allogeneic graft rejection, whole body imaging reveals that RA signaling is temporally and spatially restricted to the site of inflammation. Conditional ablation of RA signaling in T cells significantly interferes with CD4+ T cell effector function, migration, and polarity. These findings provide a new perspective of the role of RA as a mediator directly controlling CD4+ T cell differentiation and immunity.

Pino-Lagos, Karina; Guo, Yanxia; Brown, Chrysothemis; Alexander, Matthew P.; Elgueta, Raul; Bennett, Kathryn A.; De Vries, Victor; Nowak, Elizabeth; Blomhoff, Rune; Sockanathan, Shanthini; Chandraratna, Roshantha A.; Dmitrovsky, Ethan



Immunohistochemical Distribution of Adult T-Cell Leukemia-Derived Factor\\/Thioredoxin in Epithelial Components of Normal and Pathologic Human Skin Conditions  

Microsoft Academic Search

Tissues from normal human skin and various skin diseases were studied with the immunoperoxidase technique using an antibody to adult T-cell leukemia-derived factor (ADF), a homologue of human thioredoxin. Normal human skin Showed positive immunostaining for ADF\\/thioredoxin in the outer root sheath of hair follicle, sebaceous glands, and secreting components of apocrine and eccrine sweat units, but not in the

Hisashi Wakita; Junji Yodoi; Hiroshi Masutani; Ken-ichi Toda; Masahiro Takigawa



Autoimmune gastritis mediated by CD4+ T cells promotes the development of gastric cancer.  


Chronic inflammation is a major risk factor for cancer, including gastric cancers and other gastrointestinal cancers. For example, chronic inflammation caused by autoimmune gastritis (AIG) is associated with an increased risk of gastric polyps, gastric carcinoid tumors, and possibly adenocarcinomas. In this study, we characterized the progression of gastric cancer in a novel mouse model of AIG. In this model, disease was caused by CD4(+) T cells expressing a transgenic T-cell receptor specific for a peptide from the H(+)/K(+) ATPase proton pump, a protein expressed by parietal cells in the stomach. AIG caused epithelial cell aberrations that mimicked most of those seen in progression of human gastric cancers, including chronic gastritis followed by oxyntic atrophy, mucous neck cell hyperplasia, spasmolytic polypeptide-expressing metaplasia, dysplasia, and ultimately gastric intraepithelial neoplasias. Our work provides the first direct evidence that AIG supports the development of gastric neoplasia and provides a useful model to study how inflammation drives gastric cancer. PMID:23378345

Nguyen, Thanh-Long M; Khurana, Shradha S; Bellone, Clifford J; Capoccia, Benjamin J; Sagartz, John E; Kesman, Russell A; Mills, Jason C; DiPaolo, Richard J



Nature and nurture in Foxp3(+) regulatory T cell development, stability, and function.  


Foxp3(+) regulatory T lymphocytes (Treg) are critical homeostatic regulators of immune and inflammatory responses. Their absence leads to fulminant multiorgan autoimmunity. This review explores recent studies that have altered our emerging view of the development, stability, and plasticity of these cells. Treg appear not to be a single entity, but a family of immunomodulatory cell types with shared capabilities. On a first level, Treg may alternatively form in response to developmental cues in the thymus as a distinct lineage of CD4(+) T cells or adaptively, in response to environmental cues received by mature conventional CD4(+) T lymphocytes. These 2 populations bear distinct specificity, stability, and genetic profiles and are differentially used in immune responses. Secondarily, in a manner analogous to the generation of T helper (Th)-1, Th2, and other T cell subsets, Treg may further specialize, adapting to the needs of their immunologic surroundings. Treg therefore comprise developmentally distinct, functionally overlapping cell populations that are uniquely designed to preserve immunologic homeostasis. They combine an impressive degree of both stability and adaptability. PMID:22240298

Geiger, Terrence L; Tauro, Sharyn



Aire-dependent thymic development of tumor-associated regulatory T cells.  


Despite considerable interest in the modulation of tumor-associated Foxp3(+) regulatory T cells (T(regs)) for therapeutic benefit, little is known about the developmental origins of these cells and the nature of the antigens that they recognize. We identified an endogenous population of antigen-specific T(regs) (termed MJ23 T(regs)) found recurrently enriched in the tumors of mice with oncogene-driven prostate cancer. MJ23 T(regs) were not reactive to a tumor-specific antigen but instead recognized a prostate-associated antigen that was present in tumor-free mice. MJ23 T(regs) underwent autoimmune regulator (Aire)-dependent thymic development in both male and female mice. Thus, Aire-mediated expression of peripheral tissue antigens drives the thymic development of a subset of organ-specific T(regs), which are likely coopted by tumors developing within the associated organ. PMID:23471412

Malchow, Sven; Leventhal, Daniel S; Nishi, Saki; Fischer, Benjamin I; Shen, Lynn; Paner, Gladell P; Amit, Ayelet S; Kang, Chulho; Geddes, Jenna E; Allison, James P; Socci, Nicholas D; Savage, Peter A



Aire-dependent thymic development of tumor-associated regulatory T cells*  

PubMed Central

Despite considerable interest in the modulation of tumor-associated Foxp3+ regulatory T cells (Tregs) for therapeutic benefit, little is known about the developmental origins of these cells and the nature of the antigens that they recognize. Here, we identified an endogenous population of antigen-specific Tregs (termed “MJ23” Tregs) found recurrently enriched in the tumors of mice with oncogene-driven prostate cancer. MJ23 Tregs were not reactive to a tumor-specific antigen, but instead recognized a prostate-associated antigen that was present in tumor-free mice. MJ23 Tregs underwent Aire-dependent thymic development in both male and female mice. Thus Aire-mediated expression of peripheral tissue antigens drives the thymic development of a subset of organ-specific Tregs, which are likely co-opted by tumors developing within the associated organ.

Malchow, Sven; Leventhal, Daniel S.; Nishi, Saki; Fischer, Benjamin I.; Shen, Lynn; Paner, Gladell P.; Amit, Ayelet S.; Kang, Chulho; Geddes, Jenna E.; Allison, James P.; Socci, Nicholas D.; Savage, Peter A.



Development of V?2V?2+ T Cell Responses during Active Mycobacterial Coinfection of Simian Immunodeficiency Virus-Infected Macaques Requires Control of Viral Infection and Immune Competence of CD4+ T Cells  

PubMed Central

V?2V?2+ T cells play a role in antimicrobial responses. It is unknown whether adaptive V?2V?2+ T cell responses during active mycobacterial coinfection of human immunodeficiency virus–infected humans can be generated during effective antiretroviral treatment. Here, simian immunodeficiency virus (SIV)mac-infected macaques previously exposed to bacille Calmette-Guérin (BCG) were reinfected with BCG, were treated either with tenofovir or tenofovir plus indinavir, and were assessed for the development of V?2V?2+ T cell responses during active BCG coinfection. A restored capacity of V?2V?2T+ cells to undergo major expansions and pulmonary migration during active BCG coinfection was detected after simultaneous BCG reinfection and treatment with tenofovir of the SIVmac-infected macaques. Interestingly, a restored expansion of V?2V?2+ T cells in the SIVmac/BCG-coinfected macaques was detectable, even though antiretroviral treatment was initiated 1 month after BCG reinfection. Importantly, the restored expansion of V?2V?2+ T cells coincided with increases in numbers of purified protein derivative–specific interferon-?–producing CD4+ T cells and increases in the magnitude of their proliferative responses. In contrast, the SIVmac-infected control macaques exhibited diminished responses of V?2V?2+ T cells and mycobacterium-specific CD4+ T cells during active BCG coinfection. Our results suggest that the development of adaptive immune responses of phosphoantigen-specific V?2V?2+ T cells during active mycobacterium/HIV coinfection requires control of viral infection and immune competence of peptide-specific CD4+ T cells.

Shen, Ling; Shen, Yun; Huang, Dan; Qiu, Liyou; Sehgal, Prabhat; Du, George Z.; Miller, Michael D.; Letvin, Norman L.; Chen, Zheng W.



Disordered T-Cell Development and T-Cell Malignancies in SCL LMO1 Double-Transgenic Mice: Parallels with E2A-Deficient Mice  

PubMed Central

The gene most commonly activated by chromosomal rearrangements in patients with T-cell acute lymphoblastic leukemia (T-ALL) is SCL/tal. In collaboration with LMO1 or LMO2, the thymic expression of SCL/tal leads to T-ALL at a young age with a high degree of penetrance in transgenic mice. We now show that SCL LMO1 double-transgenic mice display thymocyte developmental abnormalities in terms of proliferation, apoptosis, clonality, and immunophenotype prior to the onset of a frank malignancy. At 4 weeks of age, thymocytes from SCL LMO1 mice show 70% fewer total thymocytes, with increased rates of both proliferation and apoptosis, than control thymocytes. At this age, a clonal population of thymocytes begins to populate the thymus, as evidenced by oligoclonal T-cell-receptor gene rearrangements. Also, there is a dramatic increase in immature CD44+ CD25? cells, a decrease in the more mature CD4+ CD8+ cells, and development of an abnormal CD44+ CD8+ population. An identical pattern of premalignant changes is seen with either a full-length SCL protein or an amino-terminal truncated protein which lacks the SCL transactivation domain, demonstrating that the amino-terminal portion of SCL is not important for leukemogenesis. Lastly, we show that the T-ALL which develop in the SCL LMO1 mice are strikingly similar to those which develop in E2A null mice, supporting the hypothesis that SCL exerts its oncogenic action through a functional inactivation of E proteins.

Chervinsky, David S.; Zhao, Xian-Feng; Lam, Du H.; Ellsworth, MaryKay; Gross, Kenneth W.; Aplan, Peter D.



[Functionally active T-cells and T-lymphocyte precursors in the thymus of newborn mice irradiated in the intrauterine period of development].  


Mice were irradiated in dose of 2 Gy in 14 or 17 days of gestation. Irradiation retarded the increase of cell number in developing thymuses but in the day of birth the number of thymocytes was normalized. In normal development SC-1+ cells (T cell precursors) disappeared from the thymus immediately before the birth. After the irradiation they persisted in the newborn thymus. Mitogenic responses of newborn thymocytes on the action of thymic peptides and T cell mitogens were decreased after the fetal irradiation (adult irradiation enhances mitogenic response of thymocytes). The helper activity of thymocytes in humoral immunity was decreased after the fetal irradiation in more degree and helper activity in splenic colony-formation--in less degree than after the adult irradiation. The consequences of the irradiation in 14 and 17 days of gestation were similar. PMID:8148981

Iarilin, A A; Kharchenko, T Iu; Sharova, N I


Uptake and Presentation of Antigen to T Cells by Primary Colonic Epithelial Cells in Normal and Diseased States  

Microsoft Academic Search

Background & Aims: The immunoregulatory properties of primary colonic epithelial cells (CECs) have not been defined. The ability of CECs from wild-type and interleukin 2–deficient (IL-2?\\/?) mice to take up a complex protein antigen and present peptides via MHC molecules to T cells was assessed and contrasted with that of primary small intestinal epithelial cells (SIECs). Methods: Uptake of fluorescein



Thymic T Cell Development and Progenitor Localization Depend on CCR7  

Microsoft Academic Search

T cell differentiation in the adult thymus depends on sequential interactions between lymphoid progenitors and stromal cells found in distinct regions of the cortex and medulla. Therefore, migration of T cell progenitors through distinct stromal environments seems to be a crucial process regulating differentiation and homeostasis inside the thymus. Here we show that CCR7-deficient mice are distinguished by a disturbed

Ana Misslitz; Oliver Pabst; Gabriele Hintzen; Lars Ohl; Elisabeth Kremmer; Howard T. Petrie; Reinhold Förster


Myelin Oligodendrocyte Glycoprotein-specific T Cell Receptor Transgenic Mice Develop Spontaneous Autoimmune Optic Neuritis  

Microsoft Academic Search

Multiple sclerosis (MS) is considered to be an autoimmune disease of the central nervous sys- tem (CNS) that in many patients first presents clinically as optic neuritis. The relationship of optic neuritis to MS is not well understood. We have generated novel T cell receptor (TCR) transgenic mice specific for myelin oligodendrocyte glycoprotein (MOG). MOG-specific transgenic T cells are not

Estelle Bettelli; Maria Pagany; Howard L. Weiner; Christopher Linington; Raymond A. Sobel; Vijay K. Kuchroo


Repetitive pertussis toxin promotes development of regulatory T cells and prevents central nervous system autoimmune disease.  


Bacterial and viral infections have long been implicated in pathogenesis and progression of multiple sclerosis (MS). Incidence and severity of its animal model experimental autoimmune encephalomyelitis (EAE) can be enhanced by concomitant administration of pertussis toxin (PTx), the major virulence factor of Bordetella pertussis. Its adjuvant effect at the time of immunization with myelin antigen is attributed to an unspecific activation and facilitated migration of immune cells across the blood brain barrier into the central nervous system (CNS). In order to evaluate whether recurring exposure to bacterial antigen may have a differential effect on development of CNS autoimmunity, we repetitively administered PTx prior to immunization. Mice weekly injected with PTx were largely protected from subsequent EAE induction which was reflected by a decreased proliferation and pro-inflammatory differentiation of myelin-reactive T cells. Splenocytes isolated from EAE-resistant mice predominantly produced IL-10 upon re-stimulation with PTx, while non-specific immune responses were unchanged. Longitudinal analyses revealed that repetitive exposure of mice to PTx gradually elevated serum levels for TGF-? and IL-10 which was associated with an expansion of peripheral CD4(+)CD25(+)FoxP3(+) regulatory T cells (Treg). Increased frequency of Treg persisted upon immunization and thereafter. Collectively, these data suggest a scenario in which repetitive PTx treatment protects mice from development of CNS autoimmune disease through upregulation of regulatory cytokines and expansion of CD4(+)CD25(+)FoxP3(+) Treg. Besides its therapeutic implication, this finding suggests that encounter of the immune system with microbial products may not only be part of CNS autoimmune disease pathogenesis but also of its regulation. PMID:21209857

Weber, Martin S; Benkhoucha, Mahdia; Lehmann-Horn, Klaus; Hertzenberg, Deetje; Sellner, Johann; Santiago-Raber, Marie-Laure; Chofflon, Michel; Hemmer, Bernhard; Zamvil, Scott S; Lalive, Patrice H



The major CD8 T cell effector memory subset in the normal and Chlamydia trachomatis-infected human endocervix is low in perforin  

PubMed Central

Background The local tissue microenvironment plays an important role in the induction, homing, maintenance and development of effector functions of T cells. Thus, site-specific differences in phenotypes of mucosal and systemic T cell populations have been observed. Chlamydia trachomatis most commonly infects the endocervix in women, yet little is known about Chlamydia-specific effector T cell immunity at this unique mucosal site. Our previous flow-cytometry-based study of cervical-cytobrush retrieved cells indicated that CD8 T cells are significantly increased in the C. trachomatis-infected human endocervix. The cytolytic function of CD8 T cells is important in the protective immunity against many intracellular pathogens, and requires the cytolytic granule perforin to facilitate the entry of other molecules that mediate the lysis of target cells. Determination of perforin expression of the CD8 T cell population in the endocervix would therefore provide insights on the granule-mediated cytolytic potential of these cells at this site. Results Our histological data revealed that C. trachomatis-infected tissues have significantly higher numbers of CD3 and CD8 T cells compared to non-infected tissues (p<0.01), and that the majority of CD8+ cells do not express perforin in situ. A subsequent flow cytometric analysis of paired blood and endocervix-derived cells (n=16) revealed that while all the CD8 T cell subsets: naïve, effector memory (TEM), central memory (TCM) and terminally differentiated effector memory (TEMRA) can be found in the blood, the endocervix is populated mainly by the TEM CD8 T cell subset. Our data also showed that perforin expression in the TEM population is significantly lower in the endocervix than in the blood of C. trachomatis positive women (n=15; p<0.0001), as well as in C. trachomatis-negative individuals (n=6; p<0.05). Interestingly, our in vitro co-culture study suggests that the exposure of HeLa 229 cervical epithelial cells to IFN gamma could potentially induce a decrease in perforin content in CD8 TEM cells in the same microenvironment. Conclusions The low perforin content of CD8 TEM cells in the endocervix, the local site of C. trachomatis infection in women, may reflect the unique immunological environment that balances immune protection against sexually transmitted infections and immune- tolerance to support conception.



Constitutive expression of interleukin 4 in vivo does not lead to the development of T helper 2 type CD8 + T cells secreting interleukin 4 or interleukin 5  

Microsoft Academic Search

Interleukin 4 (IL-4) has been shown to commit CD8+ T cells to a T helper (Th) 2 functional phenotype in vitro. To study the effects of IL-4 on CD8+ T cell development in vivo we analysed the CD8+ T cell phenotype in mice constitutively expressing IL-4. Purified CD8+ T cells from uninfected or flu infected IL-4 transgenic (tg) animals produced

Klaus Josef Erb; Sam Hou; Lisa Hyland; Joanna Kirman; Heidrun Moll; Graham Le Gros



CCA [ N -(2-carboxyphenyl)-4-Chloroanthranilic acid disodium salt], a newly developed immunomodulating drug, suppresses T-cell activation by acting on macrophages  

Microsoft Academic Search

The cellular mechanism of action of a newly developed drug, CCA,N-(2-carboxyphenyl)-4-chloroanthranilic acid disodium salt, on PHA-, autologous mixed lymphocyte reaction (AMLR)-, and phorbol myristate acetate (PMA)-stimulated T-cell proliferation was investigated. Addition of 50 µg of CCA per milliliter suppressed PHA- and AMLR-stimulaled T-cell proliferation. In contrast. CCA failed to suppress PMA-stimulated macrophage-depleted T-cell proliferation. After treatment of T cells or

Tsutomu Takeuchi; Jun Koide; Osamu Hosono; Makoto Takano; Tohru Abe



A significant proportion of normal resting B cells are induced to secrete immunoglobulin through contact with anti-receptor antibody-activated helper T cells in clonal cultures.  


This report describes single-cell techniques to address the nature of a cellular interaction in which activated T lymphocytes stimulate small resting B cells to develop into antibody-forming cell clones in the absence of any surface immunoglobulin ligand or an antigen bridge. The cloned T helper cell line E9.D4 was stimulated with the anti-V beta 8 antibody F23.1 bound to the plastic of Terasaki 10-ul culture wells. When an excess of T helper lymphocytes was used (1,000 X-irradiated or 600 unirradiated, stimulated E9.D4 cells), 10-25% of B cells responded by antibody formation as judged by an enzyme-linked immunosorbent assay performed after 5 days of culture. When one of a very small number of B cells were present, the rate-limiting step to antibody-forming cell formation was the number of T cells present. Far fewer T cells sufficed for stimulation when culture trays were tilted to force T and B cells into proximity at the sulcus formed at the bottom edge of the culture wells. When T cell numbers were limiting, unirradiated T cells out-performed irradiated T cells. Some cell clones held for 7 days switched to IgG antibody production. E9.D4 supernatants were virtually ineffective in causing B cell stimulation, even when 3T3 filler cells were added to support cultures. The results suggest that cell contact, and perhaps conjugate formation, with a strongly activated T cell can cause changes in the adjacent resting B cells akin to those of Ig receptor cross-linking, following which a lymphokine flux (even one not involving IL 4 and 5) promotes antibody-forming cell development. PMID:2965647

Riedel, C; Owens, T; Nossal, G J



CD1 expression and CD1-restricted T cell activity in normal and tumour-bearing human liver  

Microsoft Academic Search

CD1d-restricted natural killer T (NKT) cells expressing invariant V?14J?18 T cell receptor ?-chains are abundant in murine\\u000a liver and are implicated in the control of malignancy, infection and autoimmunity. Invariant NKT cells have potent anti-metastatic\\u000a effects in mice and phase I clinical trials involving their homologues in humans are ongoing. However, invariant NKT cells\\u000a are less abundant in human liver

Tony Kenna; Margaret O’Brien; Andrew E. Hogan; Mark A. Exley; Steven A. Porcelli; John E. Hegarty; Cliona O’Farrelly; Derek G. Doherty



Developing T-cell therapies for cancer in an academic setting.  


T-cell immunotherapies have great potential because of their exquisite targeting ability and high efficacy, but are more complex to implement since they do not readily fit the pharmaceutical model. Nonetheless, recent improvements in gene-transfer technology allow T cells directed to tumor-associated antigens to effectively eradicate even bulky malignancies. T lymphocytes also have the potential to target tumor stem cells, provided the target antigens are appropriately identified and expressed on the components used to generate the effector T-cells. Numerous problems remain before these approaches can be widely implemented, but as the success rate increases, willingness to commit the necessary resources will correspondingly increase. PMID:18593017

Brenner, Malcolm K



Temporal Expression of Bacterial Proteins Instructs Host CD4 T Cell Expansion and Th17 Development  

PubMed Central

Pathogens can substantially alter gene expression within an infected host depending on metabolic or virulence requirements in different tissues, however, the effect of these alterations on host immunity are unclear. Here we visualized multiple CD4 T cell responses to temporally expressed proteins in Salmonella-infected mice. Flagellin-specific CD4 T cells expanded and contracted early, differentiated into Th1 and Th17 lineages, and were enriched in mucosal tissues after oral infection. In contrast, CD4 T cells responding to Salmonella Type-III Secretion System (TTSS) effectors steadily accumulated until bacterial clearance was achieved, primarily differentiated into Th1 cells, and were predominantly detected in systemic tissues. Thus, pathogen regulation of antigen expression plays a major role in orchestrating the expansion, differentiation, and location of antigen-specific CD4 T cells in vivo.

Kurtz, Jonathan R.; Fan, Danhua; Winter, Sebastian E.; Baumler, Andreas J.; Jenkins, Marc K.; McSorley, Stephen J.



Follicular helper T cells poise immune responses to the development of autoimmune pathology.  


Follicular helper T cells (T(FH)) have been implicated as a lineage that provides sufficient help to B cells in order to become professional antibody producers. This T helper subset is characterized by a distinctive cell-surface phenotype (CD4(+)CD57(+)CXCR5(+)) and cytokine profile (IL-21, IL-6, and IL-27) as well as transcriptional program (BCL-6, ICOS, and PD-1). Evidence supports the concept that T(FH) subset development, as well as for other lineages, is dependent on microenvironment cues that modulate a particular transcriptional program, susceptible to plasticity. Recently, it has been shown that BCL-6 and IL-21 act as master regulators for the development and function of T(FH) cells. Moreover, costimulation via ICOS, as well as signaling proteins such as SAP constitute required elements of the regulatory network that modulates T(FH) functions. T(FH) dysregulation has been implicated in the development of autoimmune pathology, such as SLE. Indeed, the Sanroque mice associated to the mutation of Roquin, a ubiquitin ligase, essential for the regulation of ICOS and germinal center responses, constitutes a model that shares features with human SLE. Recently, the expansion of "circulating T(FH) cells" (CD4(+)CXCR5(+)ICOS(high)PD1(high)) has been described for a subset of SLE patients that share T(FH) dependent features of disease with Sanroque mice, such as glomerulonephritis and cytopenias. PMID:21167320

Gómez-Martín, Diana; Díaz-Zamudio, Mariana; Romo-Tena, Jorge; Ibarra-Sánchez, María J; Alcocer-Varela, Jorge



Thymus-independent development and negative selection of T cells expressing T cell receptor alpha/beta in the intestinal epithelium: evidence for distinct circulation patterns of gut- and thymus-derived T lymphocytes  

PubMed Central

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.



From murine to human nude/SCID: the thymus, T-cell development and the missing link.  


Primary immunodeficiencies (PIDs) are disorders of the immune system, which lead to increased susceptibility to infections. T-cell defects, which may affect T-cell development/function, are approximately 11% of reported PIDs. The pathogenic mechanisms are related to molecular alterations not only of genes selectively expressed in hematopoietic cells but also of the stromal component of the thymus that represents the primary lymphoid organ for T-cell differentiation. With this regard, the prototype of athymic disorders due to abnormal stroma is the Nude/SCID syndrome, first described in mice in 1966. In man, the DiGeorge Syndrome (DGS) has long been considered the human prototype of a severe T-cell differentiation defect. More recently, the human equivalent of the murine Nude/SCID has been described, contributing to unravel important issues of the T-cell ontogeny in humans. Both mice and human diseases are due to alterations of the FOXN1, a developmentally regulated transcription factor selectively expressed in skin and thymic epithelia. PMID:22474479

Romano, Rosa; Palamaro, Loredana; Fusco, Anna; Iannace, Leucio; Maio, Stefano; Vigliano, Ilaria; Giardino, Giuliana; Pignata, Claudio



Unaltered Negative Selection and Regulatory T cell Development of Self-reactive thymocytes in TCR transgenic Fyn-deficient Mice  

PubMed Central

The tyrosine kinase Fyn has been implicated as playing an important role in the generation of both stimulatory and inhibitory signaling events induced by TCR engagement. To assess the role of Fyn for antigen-driven negative selection and regulatory T cell (Treg) development, which are both dependent on the strength and nature of TCR signaling, we generated mice that co-express the transgenes for ovalbumin and the OT-II TCR, which recognizes a peptide from ovalbumin. In mice expressing both transgenes, negative selection, Treg development in the thymus, and the number of Treg in the periphery were each unaffected by ablation of Fyn. Moreover, fyn-/- Treg were functional, as assessed in vitro. We further tested the role of Fyn for the adaptor function of c-Cbl, using mice containing a point mutation in c-Cbl that abolishes its E3 ubiquitin ligase function but maintains its adaptor function. The functional and signaling properties of this mutant c-Cbl were unaltered in fyn-/- thymocytes. Combined, these data indicate that Fyn was not required for: the induction of central tolerance by negative selection; the adaptor protein role of c-Cbl; orthe normal development and function of Treg.

Mamchak, Alusha A.; Thien, Christine B.F.; Dagger, Samantha A.; Lyandres, Julia; Jiang, Shuwei; Langdon, Wallace Y.; DeFranco, Anthony L.



Development of transgenic mice expressing a coronavirus-specific public CD4 T cell receptor.  


Mice that are transgenic (Tg) for T cell receptor (TCR) expression are used extensively to analyze longitudinal T cell responses during effector and memory phases of the T cell response. Generation of TCR Tg mice generally requires T cell stimulation and cloning in vitro prior to amplification, processes which introduce biases into selection of the TCR that is ultimately chosen for TCR Tg mouse generation. Here we describe an alternative approach that involves no T cell stimulation or propagation in vitro. We generated mice that were transgenic for a TCR responding to a CD4 T cell epitope (epitope M133) that is immunodominant in mice infected with a neurotropic coronavirus, the JHM strain of mouse hepatitis virus. The CD4 T cell response to epitope M133 is of particular interest because it may be pathogenic, protective or regulatory, depending upon the physiological setting. We applied an iterative process in which we identified a TCR-? chain expressed by all mice that were examined ('public sequence'). This TCR-? chain was introduced into bone marrow cells with a lentivirus vector, generating TCR-? retrogenic mice. A TCR-? chain that paired with this TCR-? was then identified and used to generate a second set of TCR (?/?) retrogenic mice. After demonstrating that these cells were functional and responded to epitope M133, these TCR chains were used to generate an epitope M133-specific TCR Tg mouse. This method should be generally useful for engineering TCR Tg mice without introduction of bias caused by in vitro manipulation and propagation. PMID:23928495

Zhao, Jingxian; Fett, Craig; Pewe, Lecia; Zhao, Jincun; Perlman, Stanley



The importance of the Erk pathway in the development of linker for activation of T cells-mediated autoimmunity.  


The ability of the transmembrane adaptor protein linker for activation of T cells (LAT) to regulate T cell development, activation, survival, and homeostasis depends upon phosphorylation of its multiple tyrosine residues. The mutation of tyrosine 136 on LAT abrogates its interaction with phospholipase C-?1, causing severe ramifications on TCR-mediated signaling. Mice harboring this mutation, LATY136F mice, have significantly impaired thymocyte development; however, they rapidly develop a fatal lymphoproliferative disease marked by the uncontrolled expansion of Th2-skewed CD4(+) T cells, high levels of IgE and IgG1, and autoantibody production. In this study, we assessed the contribution of multiple signaling pathways in LATY136F disease development. The deletion of the critical signaling proteins Gads and RasGRP1 caused a further block in thymocyte development, but, over time, could not prevent CD4(+) T cell hyperproliferation. Also, restoring signaling through the NF-?B and NFAT pathways was unable to halt the development of disease. However, expression of a constitutively active Raf transgene enhanced lymphoproliferation, indicating a role for the Ras-MAPK pathway in LAT-mediated disease. PMID:22984075

Fuller, Deirdre M; Zhu, Minghua; Koonpaew, Surapong; Nelson, Mariana I; Zhang, Weiguo



Programmed cell death 1 inhibits inflammatory helper T-cell development through controlling the innate immune response.  


Programmed cell death 1 (PD-1) is an inhibitory coreceptor on immune cells and is essential for self-tolerance because mice genetically lacking PD-1 (PD-1(-/-)) develop spontaneous autoimmune diseases. PD-1(-/-) mice are also susceptible to severe experimental autoimmune encephalomyelitis (EAE), characterized by a massive production of effector/memory T cells against myelin autoantigen, the mechanism of which is not fully understood. We found that an increased primary response of PD-1(-/-) mice to heat-killed mycobacteria (HKMTB), an adjuvant for EAE, contributed to the enhanced production of T-helper 17 (Th17) cells. Splenocytes from HKMTB-immunized, lymphocyte-deficient PD-1(-/-) recombination activating gene (RAG)2(-/-) mice were found to drive antigen-specific Th17 cell differentiation more efficiently than splenocytes from HKMTB-immunized PD-1(+/+) RAG2(-/-) mice. This result suggested PD-1's involvement in the regulation of innate immune responses. Mice reconstituted with PD-1(-/-) RAG2(-/-) bone marrow and PD-1(+/+) CD4(+) T cells developed more severe EAE compared with the ones reconstituted with PD-1(+/+) RAG2(-/-) bone marrow and PD-1(+/+) CD4(+) T cells. We found that upon recognition of HKMTB, CD11b(+) macrophages from PD-1(-/-) mice produced very high levels of IL-6, which helped promote naive CD4(+) T-cell differentiation into IL-17-producing cells. We propose a model in which PD-1 negatively regulates antimycobacterial responses by suppressing innate immune cells, which in turn prevents autoreactive T-cell priming and differentiation to inflammatory effector T cells. PMID:24043779

Rui, Yuxiang; Honjo, Tasuku; Chikuma, Shunsuke



Lipopeptides of Borrelia burgdorferi outer surface proteins induce Th1 phenotype development in alphabeta T-cell receptor transgenic mice.  

PubMed Central

Induction of the appropriate T helper cell (Th) subset is crucial for the resolution of infectious diseases and the prevention of immunopathology. Some pathogens preferentially induce Th1 or Th2 responses. How microorganisms influence Th phenotype development is unknown. We asked if Borrelia burgdorferi, the spirochete which causes Lyme arthritis, can promote a cytokine milieu in which T cells which are not specific for B. burgdorferi are induced to produce proinflammatory cytokines. Using alphabeta T-cell receptor transgenic mice as a source of T cells with a defined specificity other than for B. burgdorferi, we found that B. burgdorferi induced Th1 phenotype development in ovalbumin-specific transgenic T cells. Small synthetic lipopeptides corresponding to the N-terminal sequences of B. burgdorferi outer surface lipoproteins had similar effects. B. burgdorferi and its lipopeptides induced host cells to produce interleukin-12. When the peptides were used in delipidated form, they did not induce Th1 development. These findings may be of pathogenic importance, since it is currently assumed that a Th2-mediated antibody response is protective against B. burgdorferi. Bacteria associated with reactive arthritis, namely, Yersinia enterocolitica, Shigella flexneri, and Salmonella enteritidis, had different effects. The molecular definition of pathogen-host interactions determining cytokine production should facilitate rational therapeutic interventions directing the host response towards the desired cytokine response. Here, we describe small synthetic molecules capable of inducing Th1 phenotype development.

Infante-Duarte, C; Kamradt, T



Regulatory gene network circuits underlying T-cell development from multipotent progenitors  

PubMed Central

Regulatory gene circuits enable stem and progenitor cells to detect and process developmental signals and make irreversible fate commitment decisions. To gain insight into the gene circuits underlying the T-cell specification decision in progenitor cells, we generated an updated T lymphocyte developmental gene regulatory network from genes and connections found in the literature. This reconstruction allowed us to identify candidate regulatory gene circuit elements underlying T-cell fate decision making. Here, we examine the roles of these circuits in facilitating different aspects of the decision making process, and discuss experiments to further probe their structure and function.

Kueh, Hao Yuan; Rothenberg, Ellen V.



The mSin3A Chromatin-Modifying Complex Is Essential for Embryogenesis and T-Cell Development  

PubMed Central

The corepressor mSin3A is the core component of a chromatin-modifying complex that is recruited by multiple gene-specific transcriptional repressors. In order to understand the role of mSin3A during development, we generated constitutive germ line as well as conditional msin3A deletions. msin3A deletion in the developing mouse embryo results in lethality at the postimplantation stage, demonstrating that it is an essential gene. Blastocysts derived from preimplantation msin3A null embryos and mouse embryo fibroblasts (MEFs) lacking msin3A display a significant reduction in cell division. msin3A null MEFs also show mislocalization of the heterochromatin protein, HP1?, without alterations in global histone acetylation. Heterozygous msin3A+/? mice with a systemic twofold decrease in mSin3A protein develop splenomegaly as well as kidney disease indicative of a disruption of lymphocyte homeostasis. Conditional deletion of msin3A from developing T cells results in reduced thymic cellularity and a fivefold decrease in the number of cytotoxic (CD8) T cells, while helper (CD4) T cells are unaffected. We show that CD8 development is dependent on mSin3A at a step downstream of T-cell receptor signaling and that loss of mSin3A specifically decreases survival of double-positive and CD8 T cells. Thus, msin3A is a pleiotropic gene which, in addition to its role in cell cycle progression, is required for the development and homeostasis of cells in the lymphoid lineage.

Cowley, Shaun M.; Iritani, Brian M.; Mendrysa, Susan M.; Xu, Tina; Cheng, Pei Feng; Yada, Jason; Liggitt, H. Denny; Eisenman, Robert N.



Normalization of the lymph node T cell stromal microenvironment in lpr/lpr mice is associated with SU5416-induced reduction in autoantibodies.  


The vascular-stromal elements of lymph nodes can play important roles in regulating the activities of the lymphocytes within. During model immune responses, the vascular-stromal compartment has been shown to undergo proliferative expansion and functional alterations. The state of the vascular-stromal compartment and the potential importance of this compartment in a spontaneous, chronic model of autoimmunity have not been well studied. Here, we characterize the vascular expansion in MRL-lpr/lpr lymph nodes and attempt to ask whether inhibiting this expansion can interfere with autoantibody generation. We show that characteristics of vascular expansion in enlarging MRL-lpr/lpr lymph nodes resemble that of the VEGF-dependent expansion that occurs in wild-type mice after model immunization. Surprisingly, treatment with SU5416, an inhibitor of VEGF and other receptor tyrosine kinases, did not have sustained effects in inhibiting vascular growth, but attenuated the anti-dsDNA response and altered the phenotype of the double negative T cells that are expanded in these mice. In examining for anatomic correlates of these immunologic changes, we found that the double negative T cells are localized within ectopic follicles around a central B cell patch and that these T cell-rich areas lack the T zone stromal protein ER-TR7 as well as other elements of a normal T zone microenvironment. SU5416 treatment disrupted these follicles and normalized the association between T zone microenvironmental elements and T cell-rich areas. Recent studies have shown a regulatory role for T zone stromal elements. Thus, our findings of the association of anti-dsDNA responses, double negative T cell phenotype, and altered lymphocyte microenvironment suggest the possibility that lymphocyte localization in ectopic follicles protects them from regulation by T zone stromal elements and functions to maintain autoimmune responses. Potentially, altering the lymphocyte microenvironment that is set up by the vascular-stromal compartment can be a means by which to control undesired autoimmune responses. PMID:22412930

Chyou, Susan; Tian, Sha; Ekland, Eric H; Lu, Theresa T



Deterministic and stochastic naive T cell population dynamics: symmetric and asymmetric cell division  

Microsoft Academic Search

There is growing evidence that asymmetric cell division has a key role in fate decision during T cell responses, however it is unknown if this process also has a role in the normal homeostasis of the naive T cell population. In order to explore asymmetric cell division, we develop a mathematical model in which naive T cells exist in one

Joseph Reynolds; Mark Coles; Grant Lythe; Carmen Molina-París



T Cell-Mediated Maintenance of Natural Self-Tolerance: its Breakdown as a Possible Cause of Various Autoimmune Diseases  

Microsoft Academic Search

This paper shows that elimination of a small subpopulation of peripheral T cells can elicit activation\\/expansion of self-reactive T cells from the remaining T cells and produce a wide spectrum of organ-specific and systemic auto-immune diseases in normal mice; reconstitution of the eliminated T-cell population prevents autoimmune development. This regulatory T-cell population expresses the CD25 molecule, apparently includes ‘activated’ T

Shimon Sakaguchi; Masaaki Toda; Masanao Asano; Misako Itoh; Stephen S. Morse; Noriko Sakaguchi



JNK is required for effector T-cell function but not for T-cell activation.  


The hallmark of T-cell activation is the production of interleukin 2 (IL-2). c-Jun amino-terminal kinase (JNK), a MAP kinase that phosphorylates c-Jun and other components of the AP-1 group of transcription factors, has been implicated in the activation of IL-2 expression. Previously, we found that T cells from mice deficient in the Jnk1 or Jnk2 gene can be activated and produce IL-2 normally, but are deficient in functional differentiation into Th1 or Th2 subsets. However, studies of mice with compound mutations indicate that JNK1 and JNK2 are redundant during mouse development. Here we use three new mouse models in which peripheral T cells completely lack JNK proteins or signalling, to test whether the JNK signalling pathway is crucial for IL-2 expression and T-cell activation. Unexpectedly, these T cells made more IL-2 and proliferated better than wild-type cells. However, production of effector T-cell cytokines did require JNK. Thus, JNK is necessary for T-cell differentiation but not for naive T-cell activation. PMID:10811224

Dong, C; Yang, D D; Tournier, C; Whitmarsh, A J; Xu, J; Davis, R J; Flavell, R A



A role for apoptosis-inducing factor in T cell development.  


Apoptosis-inducing factor (Aif) is a mitochondrial flavoprotein that regulates cell metabolism and survival in many tissues. We report that aif-hypomorphic harlequin (Hq) mice show thymic hypocellularity and a cell-autonomous thymocyte developmental block associated with apoptosis at the ?-selection stage, independent of T cell receptor ? recombination. No abnormalities are observed in the B cell lineage. Transgenes encoding wild-type or DNA-binding-deficient mutant Aif rectify the thymic defect, but a transgene encoding oxidoreductase activity-deficient mutant Aif does not. The Hq thymic block is reversed in vivo by antioxidant treatment, and Hq T but not B lineage cells show enhanced oxidative stress. Thus, Aif, a ubiquitous protein, serves a lineage-specific nonredundant antiapoptotic role in the T cell lineage by regulating reactive oxygen species during thymic ?-selection. PMID:22869892

Banerjee, Hridesh; Das, Abhishek; Srivastava, Smita; Mattoo, Hamid R; Thyagarajan, Krishnamurthy; Khalsa, Jasneet Kaur; Tanwar, Shalini; Das, Deepika Sharma; Majumdar, Subeer S; George, Anna; Bal, Vineeta; Durdik, Jeannine M; Rath, Satyajit



A role for apoptosis-inducing factor in T cell development  

PubMed Central

Apoptosis-inducing factor (Aif) is a mitochondrial flavoprotein that regulates cell metabolism and survival in many tissues. We report that aif-hypomorphic harlequin (Hq) mice show thymic hypocellularity and a cell-autonomous thymocyte developmental block associated with apoptosis at the ?-selection stage, independent of T cell receptor ? recombination. No abnormalities are observed in the B cell lineage. Transgenes encoding wild-type or DNA-binding–deficient mutant Aif rectify the thymic defect, but a transgene encoding oxidoreductase activity–deficient mutant Aif does not. The Hq thymic block is reversed in vivo by antioxidant treatment, and Hq T but not B lineage cells show enhanced oxidative stress. Thus, Aif, a ubiquitous protein, serves a lineage-specific nonredundant antiapoptotic role in the T cell lineage by regulating reactive oxygen species during thymic ?-selection.

Banerjee, Hridesh; Das, Abhishek; Srivastava, Smita; Mattoo, Hamid R.; Thyagarajan, Krishnamurthy; Khalsa, Jasneet Kaur; Tanwar, Shalini; Das, Deepika Sharma; Majumdar, Subeer S.; George, Anna; Bal, Vineeta; Durdik, Jeannine M.



Antigen Presenting Cells Expressing High Levels of PD-L2 Sustain the Development of CD4-T Cell Memory1  

PubMed Central

The role APCs play in the transition of T cells from effector to memory remains largely undefined. This is likely due to the low frequency at which long-lived T cells arise which hinders analysis of the events involved in memory development. Herein, we used TCR transgenic T cells to increase the frequency of long-lived T cells and developed a transfer model suitable for defining the contribution of APCs to the development of CD4-T cell memory. Accordingly, naive TCR transgenic T cells were stimulated in vitro with Ag presented by different types of APCs, transferred into MHC class II-deficient (MHC II?/?) mice for parking, and the hosts were later analyzed for long-lived T cell frequency or challenged with suboptimal dose of Ag and the long-lived cells-driven memory responses were measured. The findings indicate that B cells and CD8?+ DCs sustained elevated frequencies of long-lived T cells which yielded rapid and robust memory responses upon re-challenge with sub-optimal dose of Ag. Furthermore, both types of APCs had significant Programmed Death Ligand 2 (PD-L2) expression prior to Ag stimulation, which was maintained at a high level during presentation of Ag to T cells. Blockade of PD-L2 interaction with its receptor Programmed Death (PD-1) nullified the development of memory responses. These previously unrecognized findings suggest that targeting specific APCs for Ag presentation during vaccination could prove effective against microbial infections.

Ellis, Jason S.; Guloglu, F. Betul; Tartar, Danielle M.; Hoeman, Christine M.; Haymaker, Cara L.; Cascio, Jason A.; Wan, Xiaoxiao; Dhakal, Mermagya; VanMorlan, Amie; Yahng, Seung-Hi; Zaghouani, Habib



Different gamma delta T-Cell Receptors are Expressed on Thymocytes at Different Stages of Development  

Microsoft Academic Search

We have analyzed the structural diversity of the murine gamma delta T-cell receptor (TCR) heterodimer expressed on CD4- CD8- thymocyte populations and on TCR gamma delta -expressing hybridomas derived from thymocytes of fetal, newborn, and adult mice. We found that CD4- CD8- thymocytes derived from mice of different pre- and postnatal age preferentially express a gamma delta TCR encoded by

Kouichi Ito; Marc Bonneville; Yohtaroh Takagaki; Nobuki Nakanishi; Osami Kanagawa; Edvins G. Krecko; Susumu Tonegawa



Repression of the Transcription Factor Th-POK by Runx Complexes in Cytotoxic T Cell Development  

Microsoft Academic Search

Mouse CD4+CD8+ double-positive (DP) thymocytes differentiate into CD4+ helper-lineage cells upon expression of the transcription factor Th-POK but commit to the CD8+ cytotoxic lineage in its absence. We report the redirected differentiation of class I-restricted thymocytes into CD4+CD8- helper-like T cells upon loss of Runx transcription factor complexes. A Runx-binding sequence within the Th-POK locus acts as a transcriptional silencer

Ruka Setoguchi; Masashi Tachibana; Yoshinori Naoe; Sawako Muroi; Kaori Akiyama; Chieko Tezuka; Tsukasa Okuda; Ichiro Taniuchi



Exclusive development of T cell neoplasms in mice transplanted with bone marrow expressing activated Notch alleles  

PubMed Central

Notch is a highly conserved transmembrane protein that is involved in cell fate decisions and is found in organisms ranging from Drosophila to humans. A human homologue of Notch, TAN1, was initially identified at the chromosomal breakpoint of a subset of T-cell lymphoblastic leukemias/lymphomas containing a t(7;9) chromosomal translocation; however, its role in oncogenesis has been unclear. Using a bone marrow reconstitution assay with cells containing retrovirally transduced TAN1 alleles, we analyzed the oncogenic potential of both nuclear and extranuclear forms of truncated TAN1 in hematopoietic cells. Although the Moloney leukemia virus long terminal repeat drives expression in most hematopoietic cell types, retroviruses encoding either form of the TAN1 protein induced clonal leukemias of exclusively immature T cell phenotypes in approximately 50% of transplanted animals. All tumors overexpressed truncated TAN1 of the size and subcellular localization predicted from the structure of the gene. These results show that TAN1 is an oncoprotein and suggest that truncation and overexpression are important determinants of transforming activity. Moreover, the murine tumors caused by TAN1 in the bone marrow transplant model are very similar to the TAN1-associated human tumors and suggest that TAN1 may be specifically oncotropic for T cells.



Hypoxia and hypoxia-inducible factors as regulators of T cell development, differentiation, and function.  


Oxygen is a molecule that is central to cellular respiration and viability, yet there are multiple physiologic and pathological contexts in which cells experience conditions of insufficient oxygen availability, a state known as hypoxia. Given the metabolic challenges of a low oxygen environment, hypoxia elicits a range of adaptive responses at the cellular, tissue, and systemic level to promote continued survival and function. Within this context, T lymphocytes are a highly migratory cell type of the adaptive immune system that frequently encounters a wide range of oxygen tensions in both health and disease. It is now clear that oxygen availability regulates T cell differentiation and function, a response orchestrated in large part by the hypoxia-inducible factor transcription factors. Here, we discuss the physiologic scope of hypoxia and hypoxic signaling, the contribution of these pathways in regulating T cell biology, and current gaps in our understanding. Finally, we discuss how emerging therapies that modulate the hypoxic response may offer new modalities to alter T cell function and the outcome of acute and chronic pathologies. PMID:22961658

McNamee, Eóin N; Korns Johnson, Darlynn; Homann, Dirk; Clambey, Eric T



Normal psychomotor development.  


"Psychomotor" development refers to changes in a child's cognitive, emotional, motor, and social capacities from the beginning of life throughout fetal and neonatal periods, infancy, childhood, and adolescence. It occurs in a variety of domains and a wide range of theories makes understanding children's development a challenging undertaking. Different models have tried to interpret the origins of human behavior, the pattern of developmental changes over time, and the individual and contextual factors that could direct child development. No single theory has been able to account for all aspects of child development, but each of them may contribute an important piece to the child development puzzle. Although theories sometimes disagree, much of their information is complementary rather than contradictory. The knowledge of child typical development and related theories and models is greatly useful for clinical practice, leading to recognition of developmental disorders and the ways in which they can be approached and treated. In this chapter, traditional and more modern concepts around functional development of psychomotor abilities are reported, firstly more in general and then specifically in the motor domain. PMID:23622146

Cioni, Giovanni; Sgandurra, Giuseppina



Genetic evidence for an evolutionarily conserved role of IL-7 signaling in T cell development of zebrafish.  


In mammals, the cytokine IL-7 is a key regulator of various aspects of lymphocyte differentiation and homeostasis. Because of the difficulty of identifying cytokine homologs in lower vertebrates and the paucity of assay systems and reagents, the degree of functional conservation of cytokine signaling pathways, particularly those pertaining to lymphocyte development, is unclear. In this article, we report on the analysis and characterization of three zebrafish mutants with severely impaired thymopoiesis. The identification of affected genes by positional cloning revealed components of the IL-7 signaling pathway. A presumptive null allele of the zebrafish homolog of the IL-7R?-chain causes substantially reduced cellularity of the thymus but spares B cell development in the kidney. Likewise, nonsense mutations in the zebrafish homologs of janus kinases JAK1 and JAK3 preferentially affect T cell development. The functional interactions of the cytokine receptor components were examined in the three groups of fish hetero- or homozygous for either il7r and jak1, il7r and jak3, or jak1 and jak3 mutations. The differential effects on T cell development arising from the different genotypes could be explained on the basis of the known structure of the mammalian IL-7R complex. Because IL-7 signaling appears to be a universal requirement for T cell development in vertebrates, the mutants described in this article represent alternative animal models of human immunodeficiency syndromes amenable to large-scale genetic and chemical screens. PMID:21562163

Iwanami, Norimasa; Mateos, Fernando; Hess, Isabell; Riffel, Nico; Soza-Ried, Cristian; Schorpp, Michael; Boehm, Thomas



Human T Cell Lymphotropic Virus Type 1 Infection and Early Neurologic Development: A Pilot Study of 48 Children  

PubMed Central

To determine whether human T cell lymphotropic virus type 1 (HTLV-1) infection is associated with delayed neurological development, we examined 48 Peruvian children with exposure to HTLV-1 who were identified at the Instituto Materno-Perinatal. Compared with 38 HTLV-1–seronegative children, the 10 seropositive children did not have higher rates of neurodevelopmental delay. Long-term follow-up is planned.

Montano, S. M.; Zunt, J. R.; Rodriguez, L.; Quispe, I.; Rodriguez, C.; Altamirano, J.; Bautista, C. T.; Alarcon, J. O. V.; Longstreth, W. T.; Holmes, K. K.



The Nuclear Effector of Wnt-Signaling, Tcf1, Functions as a T-Cell-Specific Tumor Suppressor for Development of Lymphomas  

PubMed Central

The HMG-box factor Tcf1 is required during T-cell development in the thymus and mediates the nuclear response to Wnt signals. Tcf1?/? mice have previously been characterized and show developmental blocks at the CD4?CD8? double negative (DN) to CD4+CD8+ double positive transition. Due to the blocks in T-cell development, Tcf1?/? mice normally have a very small thymus. Unexpectedly, a large proportion of Tcf1?/? mice spontaneously develop thymic lymphomas with 50% of mice developing a thymic lymphoma/leukemia at the age of 16 wk. These lymphomas are clonal, highly metastatic, and paradoxically show high Wnt signaling when crossed with Wnt reporter mice and have high expression of Wnt target genes Lef1 and Axin2. In wild-type thymocytes, Tcf1 is higher expressed than Lef1, with a predominance of Wnt inhibitory isoforms. Loss of Tcf1 as repressor of Lef1 leads to high Wnt activity and is the initiating event in lymphoma development, which is exacerbated by activating Notch1 mutations. Thus, Notch1 and loss of Tcf1 functionally act as collaborating oncogenic events. Tcf1 deficiency predisposes to the development of thymic lymphomas by ectopic up-regulation of Lef1 due to lack of Tcf1 repressive isoforms and frequently by cooperating activating mutations in Notch1. Tcf1 therefore functions as a T-cell–specific tumor suppressor gene, besides its established role as a Wnt responsive transcription factor. Thus, Tcf1 acts as a molecular switch between proliferative and repressive signals during T-lymphocyte development in the thymus.

Tiemessen, Machteld M.; Baert, Miranda R. M.; Schonewille, Tom; Brugman, Martijn H.; Famili, Farbod; Salvatori, Daniela C. F.; Meijerink, Jules P. P.; Ozbek, Ugur; Clevers, Hans; van Dongen, Jacques J. M.; Staal, Frank J. T.



LKB1 Mediates the Development of Conventional and Innate T Cells via AMP-Dependent Kinase Autonomous Pathways  

PubMed Central

The present study has examined the role of the serine/threonine kinase LKB1 in the survival and differentiation of CD4/8 double positive thymocytes. LKB1-null DPs can respond to signals from the mature ?/? T-cell-antigen receptor and initiate positive selection. However, in the absence of LKB1, thymocytes fail to mature to conventional single positive cells causing severe lymphopenia in the peripheral lymphoid tissues. LKB1 thus appears to be dispensable for positive selection but important for the maturation of positively selected thymocytes. LKB1 also strikingly prevented the development of invariant V?14 NKT cells and innate TCR ?? gut lymphocytes. Previous studies with gain of function mutants have suggested that the role of LKB1 in T cell development is mediated by its substrate the AMP-activated protein kinase (AMPK). The present study now analyses the impact of AMPK deletion in DP thymocytes and shows that the role of LKB1 during the development of both conventional and innate T cells is mediated by AMPK-independent pathways.

Zarrouk, Marouan; Rolf, Julia; Cantrell, Doreen Ann



Ikaros is required to survive positive selection and to maintain clonal diversity during T-cell development in the thymus.  


The zinc-finger protein Ikaros is a key player in T-cell development and a potent tumor suppressor in thymocytes. To understand the molecular basis of its function, we disabled Ikaros activity in vivo using a dominant negative Ikaros transgene (DN-IkTg). In DN-IkTg mice, T-cell development was severely suppressed, and positively selected thymocytes clonally expanded, resulting in a small thymus with a heavily skewed T-cell receptor (TCR) repertoire. Notably, DN-IkTg induced vigorous proliferation concomitant to downregulation of antiapoptotic factor expression such as Bcl2. Ikaros activity was required during positive selection, and specifically at the CD4(+)CD8(lo) intermediate stage of thymocyte differentiation, where it prevented persistent TCR signals from inducing aberrant proliferation and expansion. In particular, DN-IkTg induced the accumulation of CD4 single-positive (SP) thymocytes with a developmentally transitional phenotype, and it imposed a developmental arrest accompanied by massive apoptosis. Thus, we identified an in vivo requirement for Ikaros function, which is to suppress the proliferative potential of persistent TCR signals and to promote the survival and differentiation of positively selected thymocytes. PMID:23908463

Tinsley, Kevin W; Hong, Changwan; Luckey, Megan A; Park, Joo-Young; Kim, Grace Y; Yoon, Hee-Won; Keller, Hilary R; Sacks, Andrew J; Feigenbaum, Lionel; Park, Jung-Hyun



Differentiation and persistence of memory CD8+ T cells depend on T cell factor 1  

PubMed Central

T cell factor 1 (TCF-1) is a transcription factor known to act downstream of the canonical Wnt pathway and is essential for normal T cell development. However, its physiological roles in mature CD8+ T cell responses are unknown. Here we showed that TCF-1 deficiency limited proliferation of CD8+ effector T cells and impaired their differentiation towards a central memory phenotype. Moreover, TCF-1-deficient memory CD8+ T cells were progressively lost over time, exhibiting reduced expression of the anti-apoptotic molecule Bcl-2, interleukin-2 receptor ? chain and diminished IL-15-driven proliferation. TCF-1 was directly associated with the Eomes allele and the Wnt-TCF-1 pathway was necessary and sufficient for optimal Eomes expression in naïve and memory CD8+ T cells. Importantly, forced expression of Eomes partly protected TCF-1-deficient memory CD8+ T cells from time-dependent attrition. Our studies thus identify TCF-1 as a critical player in a transcriptional program that regulates memory CD8 differentiation and longevity.

Zhou, Xinyuan; Yu, Shuyang; Zhao, Dong-Mei; Harty, John T.; Badovinac, Vladimir P.; Xue, Hai-Hui



Essential role for caspase 8 in T-cell homeostasis and T-cell-mediated immunity  

PubMed Central

Defects in death receptor-mediated apoptosis have been linked to cancer and autoimmune disease in humans. The in vivo role of caspase 8, a component of this pathway, has eluded analysis in postnatal tissues because of the lack of an appropriate animal model. Targeted disruption of caspase 8 is lethal in utero. We generated mice with a targeted caspase 8 mutation that is restricted to the T-cell lineage. Despite normal thymocyte development in the absence of caspase 8, we observed a marked decrease in the number of peripheral T-cells and impaired T-cell response ex vivo to activation stimuli. caspase 8 ablation protected thymocytes and activated T-cells from CD95 ligand but not anti-CD3-induced apoptosis, or apoptosis activated by agents that are known to act through the mitochondria. caspase 8 mutant mice were unable to mount an immune response to viral infection, indicating that caspase 8 deletion in T-cells leads to immunodeficiency. These findings identify an essential, cell-stage-specific role for caspase 8 in T-cell homeostasis and T-cell-mediated immunity. This is consistent with the recent identification of caspase 8 mutations in human immunodeficiency.

Salmena, Leonardo; Lemmers, Benedicte; Hakem, Anne; Matysiak-Zablocki, Elzbieta; Murakami, Kiichi; Au, P.Y. Billie; Berry, Donna M.; Tamblyn, Laura; Shehabeldin, Amro; Migon, Eva; Wakeham, Andrew; Bouchard, Denis; Yeh, Wen Chen; McGlade, Jane C.; Ohashi, Pamela S.; Hakem, Razqallah



Expression of the Runt domain-encoding PEBP2 alpha genes in T cells during thymic development.  

PubMed Central

The PEBP2 alpha A and PEBP2 alpha B genes encode the DNA-binding subunit of a murine transcription factor, PEBP2, which is implicated as a T-cell-specific transcriptional regulator. These two related genes share the evolutionarily conserved region encoding the Runt domain. PEBP2 alpha B is the murine counterpart of human AML1, which is located at the breakpoints of the 8;21 and 3;21 chromosome translocations associated with acute myeloid leukemia. Northern (RNA) blots of various adult mouse tissues revealed that the levels of expression of both genes were most prominent in the thymus. Furthermore, transcripts of PEBP2 alpha A and mouse AML1/PEBP2 alpha B were detected in T lymphocytes in the thymuses from day 16 embryos and newborns, as well as 4-week-old adult mice, by in situ hybridization. The expression of the genes persisted in peripheral lymph nodes of adult mice. The transcripts were detected in all the CD4- CD8-, CD4+ CD8+, CD4+ CD8-, and CD4- CD8+ cell populations. The results indicated that both genes are expressed in T cells throughout their development, supporting the notion that PEBP2 is a T-cell-specific transcription factor. Transcripts of mouse AML1/PEBP2 alpha B were also detected in day 12 fetal hematopoietic liver and in the bone marrow cells of newborn mice. The implication of mouse AML1/PEBP2 alpha B expression in hematopoietic cells other than those of T-cell lineage is discussed in relation to myeloid leukemogenesis.

Satake, M; Nomura, S; Yamaguchi-Iwai, Y; Takahama, Y; Hashimoto, Y; Niki, M; Kitamura, Y; Ito, Y



Development of a nanoparticulate formulation of retinoic acid that suppresses Th17 cells and upregulates regulatory T cells  

PubMed Central

Retinoic acid (RA) is a small molecule capable of shunting developing T cells away from the Th17 lineage and towards the Treg phenotype, making it a potentially useful therapeutic for autoimmune and inflammatory diseases. However, therapy can be complicated by systemic toxicity and unpredictable bioavailability, making a targeted drug delivery vehicle for local therapy desirable. A promising approach is the use of nanoparticles, which have been demonstrated to increase potency and decrease toxicity of therapies in a variety of disease models including Th17 mediated diseases. Nanoparticles can also be targeted to specific cell types via surface modification, further increasing the potential specificity of this approach. We therefore constructed a nanoparticulate drug delivery platform from poly(lactic-co-glycolic acid) (PLGA) capable of encapsulating and releasing RA. Here we report the fabrication, characterization, and in vitro bioactivity of this platform. We demonstrate that RA containing PLGA nanoparticles suppress IL-17 production and ROR-?(t) expression in T cells polarized towards the Th17 phenotype in vitro with similar potency to that of free drug. Furthermore, we show that these particles enhance TGF-? dependent Foxp3 expression and IL-10 production of T cells in vitro with similar potency to free RA. Finally, we demonstrate that T cells polarized towards the Th17 phenotype in the presence of free and nanoparticulate RA have similarly suppressed ability to induce IL-6 production by fibroblasts. Our findings demonstrate the feasibility of RA delivery via biodegradable nanoparticles and represent an exciting technology for the treatment of autoimmune and inflammatory diseases.

Jeanbart, Laura; Nowyhed, Heba; Abraham, Clara; Craft, Joe



NF-?B controls Il2 and Csf2 expression during T cell development and activation process.  


Aging and dysregulation of immune responds are closely associated through a complicated but unclear mechanism. Although many theories have been proposed as overall dysregulation involved in aging, mechanisms such as efficiency of DNA repairing, over-expression of transcription factors (such as NF-?B family), and shift of cell types, are among many factors that contribute to and affect aging process. It is of great interests to understand the possible mechanism that is involved in aging immune system. Here, we report that the inducible genes Il2 and Csf2 are increased as T cells undergo activation and aging. Of particular note were the findings that the relative composition of the circulating CD4(+) T cell population changes as animals mature with an increased percentage of the population being memory/effector type cells. In addition, mRNA levels of NF-?B family genes that are essential elements for cytokine activation in adult mice and activated T cells are significantly increased. We have demonstrated that the expression of inducible genes is accompanied by increased memory/effector type cells and by increased expression level of NF-?B family genes during cell activation and development. PMID:23079711

Li, Yan; Ohms, Stephen J; Sun, Chao; Fan, Junyao



Mitochondrial Respiratory Capacity Is A Critical Regulator Of CD8+ T Cell Memory Development  

PubMed Central

Summary CD8+ T cells undergo major metabolic changes upon activation, but how metabolism influences the establishment of long-lived memory T (TM) cells after infection remains a key question. We have shown here that CD8+ TM cells, but not effector CD8+ (TE) cells, possessed substantial mitochondrial spare respiratory capacity (SRC). SRC is the extra capacity available in cells to produce energy in response to increased stress or work and as such is associated with cellular survival. We found that interleukin-15 (IL-15), a cytokine critical for CD8+ TM cells, regulated SRC and oxidative metabolism by promoting mitochondrial biogenesis and expression of carnitine palmitoyl transferase (CPT1a), a metabolic enzyme that controls the rate-limiting step to mitochondrial fatty acid oxidation (FAO). These results show how cytokines control the bioenergetic stability of TM cells after infection by regulating mitochondrial metabolism.

van der Windt, Gerritje J.W.; Everts, Bart; Chang, Chih-Hao; Curtis, Jonathan D.; Freitas, Tori C.; Amiel, Eyal; Pearce, Edward J.; Pearce, Erika L.



Homeostatic T cell proliferation in a T cell-dendritic cell coculture system  

PubMed Central

Naïve T cells do not proliferate in normal individuals in the absence of antigen stimulation, but they proliferate spontaneously when T cells are severely depleted. We show here that coculture of syngeneic dendritic cells (DC) with naïve T cells expressing a single T cell receptor also results in T cell proliferation in the absence of foreign antigen. As in lymphopenic mice, where T cell proliferation depends upon DC, this response in the coculture system requires interaction of the T cells' T cell receptor with self-peptide–MHCs on DC. This in vitro proliferation also requires soluble factors, including IL-15 secreted by DC, and can be inhibited potently by cell–cell contact with CD4+CD25+ regulatory T cells. The coculture system described may illuminate mechanisms that maintain stable numbers of T cells in normal individuals.

Ge, Qing; Palliser, Deborah; Eisen, Herman N.; Chen, Jianzhu



Recognition of glioma stem cells by genetically modified T cells targeting EGFRvIII and development of adoptive cell therapy for glioma.  


No curative treatment exists for glioblastoma, with median survival times of less than 2 years from diagnosis. As an approach to develop immune-based therapies for glioblastoma, we sought to target antigens expressed in glioma stem cells (GSCs). GSCs have multiple properties that make them significantly more representative of glioma tumors than established glioma cell lines. Epidermal growth factor receptor variant III (EGFRvIII) is the result of a novel tumor-specific gene rearrangement that produces a unique protein expressed in approximately 30% of gliomas, and is an ideal target for immunotherapy. Using PCR primers spanning the EGFRvIII-specific deletion, we found that this tumor-specific gene is expressed in three of three GCS lines. Based on the sequence information of seven EGFRvIII-specific monoclonal antibodies (mAbs), we assembled chimeric antigen receptors (CARs) and evaluated the ability of CAR-engineered T cells to recognize EGFRvIII. Three of these anti-EGFRvIII CAR-engineered T cells produced the effector cytokine, interferon-?, and lysed antigen-expressing target cells. We concentrated development on a CAR produced from human mAb 139, which specifically recognized GSC lines and glioma cell lines expressing mutant EGFRvIII, but not wild-type EGFR and did not recognize any normal human cell tested. Using the 139-based CAR, T cells from glioblastoma patients could be genetically engineered to recognize EGFRvIII-expressing tumors and could be expanded ex vivo to large numbers, and maintained their antitumor activity. Based on these observations, a ?-retroviral vector expressing this EGFRvIII CAR was produced for clinical application. PMID:22780919

Morgan, Richard A; Johnson, Laura A; Davis, Jeremy L; Zheng, Zhili; Woolard, Kevin D; Reap, Elizabeth A; Feldman, Steven A; Chinnasamy, Nachimuthu; Kuan, Chien-Tsun; Song, Hua; Zhang, Wei; Fine, Howard A; Rosenberg, Steven A



Recognition of Glioma Stem Cells by Genetically Modified T Cells Targeting EGFRvIII and Development of Adoptive Cell Therapy for Glioma  

PubMed Central

Abstract No curative treatment exists for glioblastoma, with median survival times of less than 2 years from diagnosis. As an approach to develop immune-based therapies for glioblastoma, we sought to target antigens expressed in glioma stem cells (GSCs). GSCs have multiple properties that make them significantly more representative of glioma tumors than established glioma cell lines. Epidermal growth factor receptor variant III (EGFRvIII) is the result of a novel tumor-specific gene rearrangement that produces a unique protein expressed in approximately 30% of gliomas, and is an ideal target for immunotherapy. Using PCR primers spanning the EGFRvIII-specific deletion, we found that this tumor-specific gene is expressed in three of three GCS lines. Based on the sequence information of seven EGFRvIII-specific monoclonal antibodies (mAbs), we assembled chimeric antigen receptors (CARs) and evaluated the ability of CAR-engineered T cells to recognize EGFRvIII. Three of these anti-EGFRvIII CAR-engineered T cells produced the effector cytokine, interferon-?, and lysed antigen-expressing target cells. We concentrated development on a CAR produced from human mAb 139, which specifically recognized GSC lines and glioma cell lines expressing mutant EGFRvIII, but not wild-type EGFR and did not recognize any normal human cell tested. Using the 139-based CAR, T cells from glioblastoma patients could be genetically engineered to recognize EGFRvIII-expressing tumors and could be expanded ex vivo to large numbers, and maintained their antitumor activity. Based on these observations, a ?-retroviral vector expressing this EGFRvIII CAR was produced for clinical application.

Johnson, Laura A.; Davis, Jeremy L.; Zheng, Zhili; Woolard, Kevin D.; Reap, Elizabeth A.; Feldman, Steven A.; Chinnasamy, Nachimuthu; Kuan, Chien-Tsun; Song, Hua; Zhang, Wei; Fine, Howard A.; Rosenberg, Steven A.



Differential Requirement for Rel/Nuclear Factor ?B Family Members in Natural Killer T Cell Development  

PubMed Central

Natural killer T (NKT) cells have been implicated in diverse immune responses ranging from suppression of autoimmunity to tumor rejection. Thymus-dependent NKT cells are positively selected by the major histocompatibility complex class I–like molecule CD1d, but the molecular events downstream of CD1d are still poorly understood. Here, we show that distinct members of the Rel/nuclear factor (NF)-?B family of transcription factors were required in both hematopoietic and nonhematopoietic cells for normal development of thymic NKT cells. Activation of NF-?B via the classical I?B?-regulated pathway was required in a cell autonomous manner for the transition of NK-1.1–negative precursors that express the TCR V?14-J?18 chain to mature NK-1.1–positive NKT cells. The Rel/NF-?B family member RelB, on the other hand, had to be expressed in radiation resistant thymic stromal cells for the generation of early NK-1.1–negative NKT precursors. Moreover, NF-?B–inducing kinase (NIK) was required for both constitutive thymic DNA binding of RelB and the specific induction of RelB complexes in vitro. Thus, distinct Rel/NF-?B family members in hematopoietic and nonhematopoietic cells regulate NKT cell development with a unique requirement for NIK-mediated activation of RelB in thymic stroma.

Sivakumar, Vallabhapurapu; Hammond, Kirsten J.L.; Howells, Norma; Pfeffer, Klaus; Weih, Falk



Development and Function of Invariant Natural Killer T Cells Producing TH2- and TH17-Cytokines  

PubMed Central

There is heterogeneity in invariant natural killer T (iNKT) cells based on the expression of CD4 and the IL-17 receptor B (IL-17RB), a receptor for IL-25 which is a key factor in TH2 immunity. However, the development pathway and precise function of these iNKT cell subtypes remain unknown. IL-17RB+ iNKT cells are present in the thymic CD44+/? NK1.1? population and develop normally even in the absence of IL-15, which is required for maturation and homeostasis of IL-17RB? iNKT cells producing IFN-?. These results suggest that iNKT cells contain at least two subtypes, IL-17RB+ and IL-17RB? subsets. The IL-17RB+ iNKT subtypes can be further divided into two subtypes on the basis of CD4 expression both in the thymus and in the periphery. CD4+ IL-17RB+ iNKT cells produce TH2 (IL-13), TH9 (IL-9 and IL-10), and TH17 (IL-17A and IL-22) cytokines in response to IL-25 in an E4BP4-dependent fashion, whereas CD4? IL-17RB+ iNKT cells are a retinoic acid receptor-related orphan receptor (ROR)?t+ subset producing TH17 cytokines upon stimulation with IL-23 in an E4BP4-independent fashion. These IL-17RB+ iNKT cell subtypes are abundantly present in the lung in the steady state and mediate the pathogenesis in virus-induced airway hyperreactivity (AHR). In this study we demonstrated that the IL-17RB+ iNKT cell subsets develop distinct from classical iNKT cell developmental stages in the thymus and play important roles in the pathogenesis of airway diseases.

Watarai, Hiroshi; Sekine-Kondo, Etsuko; Shigeura, Tomokuni; Motomura, Yasutaka; Yasuda, Takuwa; Satoh, Rumi; Yoshida, Hisahiro; Kubo, Masato; Kawamoto, Hiroshi; Koseki, Haruhiko; Taniguchi, Masaru



A brief primer on treatments of cutaneous T cell lymphoma, newly approved or late in development.  


Dermatologists use a variety of treatments for cutaneous T cell lymphoma (CTCL) or mycosis fungoides, in particular topical corticosteroids, psoralen and ultraviolet A phototherapy (PUVA) or ultraviolet B (UVB) phototherapy. Metastatic disease has been treated with radiotherapy, extracorporeal photophoresis, and old line chemotherapy agents such as methotrexate, chlorambucil, purine analogues, cyclophosphamide, hydroxydoxorubicin, oncovin, prednisone (CHOP), and interferon-alpha-2a. This feature will review these new agents including zanolimumab, denileukin diftitox, bexarotene, and vorinostat. Zanolimumab is a human monoclonal antibody that acts as a CD4 antagonist and has been granted orphan drug status in the US and Europe. Vorinostat (suberoylanilide hydroxamic acid) is a histone deacetylases inhibitor that has recently been approved by the FDA for the treatment of progressive, persistent, or recurrent CTCL on or after 2 systemic therapies have failed. Bexarotene is indicated in CTCL patients who are refractory to at least one prior systemic therapy. Denileukin diftitox is indicated for the treatment of patients with persistent or recurrent CTCL whose malignant cells express the CD25 component of the interleukin-2 receptor. PMID:17763605

Scheinfeld, Noah



Strategy escalation: an emerging paradigm for safe clinical development of T cell gene therapies.  


Gene therapy techniques are being applied to modify T cells with chimeric antigen receptors (CARs) for therapeutic ends. The versatility of this platform has spawned multiple options for their application with new permutations in strategies continually being invented, a testimony to the creative energies of many investigators. The field is rapidly expanding with immense potential for impact against diverse cancers. But this rapid expansion, like the Big Bang, comes with a somewhat chaotic evolution of its therapeutic universe that can also be dangerous, as seen by recently publicized deaths. Time-honored methods for new drug testing embodied in Dose Escalation that were suitable for traditional inert agents are now inadequate for these novel "living drugs". In the following, I propose an approach to escalating risk for patient exposures with these new immuno-gene therapy agents, termed Strategy Escalation, that accounts for the molecular and biological features of the modified cells and the methods of their administration. This proposal is offered not as a prescriptive but as a discussion framework that investigators may wish to consider in configuring their intended clinical applications. PMID:20537174

Junghans, Richard Paul



Limiting dilution analysis of the allo-MHC anti-paternal cytotoxic T cell response. I: Normal primigravid and multiparous pregnancies.  

PubMed Central

Anti-paternal cytotoxic T lymphocyte precursor frequencies (CTLpF) were determined by limiting dilution analysis (LDA) in the peripheral blood of eight primigravid and seven multiparous women during the three trimesters of pregnancy. In five of these women the responses to cord blood lymphocytes (CBL) and paternal lymphocytes were also determined at the time of delivery and at 6 weeks post delivery. As controls, CTLpF against unrelated third party donors were determined. A wide range of CTLpF against all three groups of targets was found in both the primigravid and multiparous women, reflecting the wide range of frequencies found in random populations. These frequencies remained fairly constant during and 6 weeks after the pregnancy. Splitwell analysis demonstrated that the responses generated in our culture system were specific to the stimulator. The LDA data conform to single-hit kinetics, indicating that only cytotoxic T cells were limiting in the assay. Proliferative responses of maternal lymphocytes to paternal, cord blood and third party MHC antigens also remained unchanged as determined by time-course mixed lymphocyte reactions (MLR). Our data suggest that there is no significant allo-stimulation or suppression of the maternal immune system during normal pregnancy. The mother remains immunocompetent and is capable of both cytotoxic and proliferative responses to paternally-derived fetal MHC antigens. Our findings confirm that in normal pregnancy the trophoblast, which is devoid of classical MHC antigens, forms an effective immune barrier which prevents interaction of the maternal and fetal immune systems.

Manyonda, I T; Pereira, R S; Pearce, J M; Sharrock, C E



Correction of accelerated autoimmune disease by early replacement of the mutated lpr gene with the normal Fas apoptosis gene in the T cells of transgenic MRL-lpr/lpr mice.  

PubMed Central

MRL-lpr/lpr mice develop a generalized autoimmune disease which includes increased autoantibody production, glomerulonephritis, and development of lymphadenopathy. The lpr genetic defect has been identified as a mutation in the Fas apoptosis gene that results in low expression of Fas mRNA. To determine the significance of the lpr mutation and T cells in the development of the autoimmune disease, we constructed transgenic MRL-lpr/lpr mice using a full-length murine Fas cDNA under the regulation of the T-cell-specific CD2 promoter and enhancer. Here we show that the early correction of the lpr gene defect in T cells eliminates glomerulonephritis and development of lymphadenopathy and decreases the levels of autoantibodies. In this model, early correction of the lpr defect in T cells is sufficient to eliminate the acceleration of autoimmune disease even in the presence of B cells and other cells that express the mutant lpr gene. Images

Wu, J; Zhou, T; Zhang, J; He, J; Gause, W C; Mountz, J D



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

PubMed Central

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-?1-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.

Shui, Jr-Wen; Hu, Mickey C.-T.; Tan, Tse-Hua



Conditional knockout mice reveal an essential role of protein phosphatase 4 in thymocyte development and pre-T-cell receptor signaling.  


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 (IC(50)) 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-gamma1-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. PMID:17060460

Shui, Jr-Wen; Hu, Mickey C-T; Tan, Tse-Hua



Functions of E2A-HEB Heterodimers in T-Cell Development Revealed by a Dominant Negative Mutation of HEB  

PubMed Central

Lymphocyte development and differentiation are regulated by the basic helix-loop-helix (bHLH) transcription factors encoded by the E2A and HEB genes. These bHLH proteins bind to E-box enhancers in the form of homodimers or heterodimers and, consequently, activate transcription of the target genes. E2A homodimers are the predominant bHLH proteins present in B-lineage cells and are shown genetically to play critical roles in B-cell development. E2A-HEB heterodimers, the major bHLH dimers found in thymocyte extracts, are thought to play a similar role in T-cell development. However, disruption of either the E2A or HEB gene led to only partial blocks in T-cell development. The exact role of E2A-HEB heterodimers and possibly the E2A and HEB homodimers in T-cell development cannot be distinguished in simple disruption analysis due to a functional compensation from the residual bHLH homodimers. To further define the function of E2A-HEB heterodimers, we generated and analyzed a dominant negative allele of HEB, which produces a physiological amount of HEB proteins capable of forming nonfunctional heterodimers with E2A proteins. Mice carrying this mutation show a stronger and earlier block in T-cell development than HEB complete knockout mice. The developmental block is specific to the ?/? T-cell lineage at a stage before the completion of V(D)J recombination at the TCR? gene locus. This defect is intrinsic to the T-cell lineage and cannot be rescued by expression of a functional T-cell receptor transgene. These results indicate that E2A-HEB heterodimers play obligatory roles both before and after TCR? gene rearrangement during the ?/? lineage T-cell development.

Barndt, Robert J.; Dai, Meifang; Zhuang, Yuan



Milky spots in the omentum develop in the absence of lymphoid tissue inducer cells and independently support B and T cell responses to peritoneal antigens  

PubMed Central

Summary The omentum is a site of B1 lymphopoiesis and immune responsiveness to T-independent antigens. However, it is unknown whether it supports immune responses independently of conventional lymphoid organs. We show that the omentum collects antigens and cells from the peritoneal cavity and supports T-dependent B cell responses, including isotype switching, somatic hypermutation and limited affinity maturation, despite the lack of identifiable follicular dendritic cells. The omentum also supports CD4 and CD8 responses to peritoneal antigens and recruits effector T cells primed in other locations. Unlike conventional lymphoid organs, milky spots in the omentum develop in the absence of lymphoid tissue inducer cells, but require CXCL13. Although the lymphoid architecture of milky spots is disrupted in lymphotoxin-deficient mice, normal architecture is restored by reconstitution with lymphotoxin-sufficient hematopoietic cells. These results indicate that the milky spots of the omentum function as unique secondary lymphoid organs that promote immunity to peritoneal antigens.

Rangel-Moreno, Javier; Moyron-Quiroz, Juan E.; Carragher, Damian M.; Kusser, Kim; Hartson, Louise; Moquin, Amy; Randall, Troy D.



Cytokines from activated T cells induce normal endothelial cells to acquire the phenotypic and functional features of AIDS-Kaposi's sarcoma spindle cells.  

PubMed Central

Kaposi's sarcoma (KS) is a proliferative disease of vascular origin particularly frequent in HIV-1-infected homosexual men (AIDS-KS) and characterized by proliferating spindle-shaped cells, angiogenesis, and inflammatory cell infiltration. Previous work has suggested that KS spindle cells are of endothelial cell origin and that chronic immune activation via the release of inflammatory cytokines may cooperate with basic fibroblast growth factor (bFGF) and the HIV-1 Tat protein in the induction and progression of AIDS-KS. Here we show that KS spindle cells have features of activated endothelial cells, and that conditioned media from activated T cells, rich in the same inflammatory cytokines increased in HIV-1-infected individuals, induce normal endothelial cells to acquire the phenotypic and functional features of KS cells. These include (a) acquisition of a similar pattern of cell surface antigen expression; (b) similar proliferative response to bFGF; (c) induction of the responsiveness to the mitogenic effect of extracellular HIV-1 Tat protein that is now able to promote the G1-S transition of endothelial cell cycle; and (d) induction in nude mice of vascular lesions closely resembling early KS as well as the lesions induced by inoculation of KS cells. These results suggest that chronic immune activation, via release of inflammatory cytokines, may play a role in the induction of KS. Images

Fiorelli, V; Gendelman, R; Samaniego, F; Markham, P D; Ensoli, B



Normal human pregnancy is associated with an elevation in the immune suppressive CD25+ CD4+ regulatory T-cell subset  

PubMed Central

CD4+ CD25+ T regulatory cells (TReg), suppress antigen-specific immune responses and are important for allograft tolerance. During pregnancy the mother tolerates an allograft expressing paternal antigens (the fetus) requiring substantial changes in immune regulation over a programmed period of time. We analysed whether immune-suppressive TReg cells were altered during pregnancy and therefore might play a part in this tolerant state. The presence of TReg cells was assessed in the blood of 25 non-pregnant, 63 pregnant and seven postnatal healthy women by flow cytometry. We observed an increase in circulating TReg cells during early pregnancy, peaking during the second trimester and then a decline postpartum. Isolated CD25+ CD4+ cells expressed FoxP3 messenger RNA, a marker of TReg cells, and suppressed proliferative responses of autologous CD4+ CD25? T cells to allogeneic dendritic cells. These data support the concept that normal pregnancy is associated with an elevation in the number of TReg cells which may be important in maintaining materno-fetal tolerance.

Somerset, David A; Zheng, Yong; Kilby, Mark D; Sansom, David M; Drayson, Mark T



T cell depletion eliminates the development of cardiac allograft vasculopathy in mice rendered tolerant by the induction of mixed chimerism.  

PubMed Central

We previously demonstrated that cardiac allografts to fully tolerant chimeric mice developed cardiac allograft vasculopathy (CAV). Here we begin to examine which components of the immune system are responsible for the pathogenesis of CAV in such tolerant recipients. B10.A/B6 mixed chimeric mice were created by receiving injections of bone marrow cells from B10.A (H-2k) mice given to C57BL/6 (B6; H-2b) mice with some preparations. B10.A skin grafts were first placed onto B10.A/B6 mixed chimeric recipients. When the donor strain skin grafts had survived perfectly for at least 56 days, B10.A hearts were transplanted heterotopically into B10.A/B6 mixed chimeric recipients. Hearts were examined for the presence of CAV 56 days later. To determine the effector cells that contribute to the development of CAV, they were treated weekly with a combination of anti-CD4/CD8 mAbs or anti-NK1.1mAb continuing until 56 days. 14 B10.A cardiac transplants of 18 otherwise untreated B10.A/B6 chimeric recipients developed CAV concurrent B6 isografts were unaffected (0/7). In chimeric recipients treated with anti-CD4/8 mAbs, the prevalence of CAV was greatly reduced (0/6, p<0.01 compared to the untreated group). Anti-NK1.1 mAb was not effective in the prevention of CAV (4/5). These data suggest that T cells may contribute in some way to the development of CAV that occurs in those fully tolerant recipients. Host T cells which may still be responsive to non-MHC antigens, including tissue specific antigens presented not on skin but on heart, may also be responsible for the development of CAV in tolerant animals.

Uehara, Shuichiro; Chase, Catharine M.; Colvin, Robert B.; Madsen, Joren C.; Russell, Paul S.



Lack of expression on cultured human T-lymphocytes of a T-cell antigen shared by the molt-4 cell line and normal human thymocytes  

Microsoft Academic Search

Summary  Four hematopoietic cell lines (CCRF-CEM, HSB-2, MOLT-4, and RPMI-8402), derived from acute lymphoblastic leukemia and expressing\\u000a T-cell surface markers (T-HCL), were studied with two specific anti-T-cell sera. The sera were raised in rabbits against human\\u000a thymocytes (anti-HTY) and against T-cells cultured in the presence of conditioned medium derived from lymphocytes stimulated\\u000a with PHA (anti-CTC). Both sera were absorbed to obtain

Franco Pandolfi; Douglas M. Strong; Guy D. Bonnard; Ronald B. Herberman



Cutting Edge: Extracellular Signal-Related Kinase Is Not Required for Negative Selection of Developing T Cells1  

PubMed Central

Signals initiated through the TCR during development can result in either survival and differentiation or cell death. High affinity signals that induce death elicit a robust yet transient activation of signaling pathways, including Erk, whereas low affinity ligands, which promote survival, generate a gradual and weaker activation of the same pathways. It was recently demonstrated that Erk localizes to distinct cellular locations in response to high and low affinity ligands. Although a requirement for Erk in positive selection is well established, its role in negative selection is controversial and, thus, the importance of Erk relocalization during development is not understood. In this study, we examined the role of Erk in negative selection using mice that are genetically deficient in both Erk1 and Erk2 in T cells. Results from three different models reveal that thymocyte deletion remains intact in the absence of Erk.

McGargill, Maureen A.; Ch'en, Irene L.; Katayama, Carol D.; Pages, Gilles; Pouyssegur, Jacques; Hedrick, Stephen M.



Protein Kinase C ? is Required for T Cell Activation and Homeostatic Proliferation  

PubMed Central

Protein kinase C? (PKC?) is highly abundant in T cells and is recruited to the immunological synapse that is formed between a T cell and a cognate antigen-presenting cell; however, its function in T cells is unknown. Here, we showed that PKC? was required for the activation of mature CD8+ T cells by stimulation through the T cell receptor. PKC??/? T cells showed poor proliferation in response to stimulation by antigen as compared to wild-type T cells, a trait shared with T cells deficient in PKC?, the most abundant PKC isoform in T cells, and the only PKC previously thought to have a specific role in T cell activation. In contrast, defective homeostatic proliferation, a function requiring recognition of self antigens, was only observed in PKC?- deficient T cells. PKC? was dispensable for the development of thymocytes; however, thymocytes from mice doubly deficient in PKC? and PKC? exhibited poor positive selection, indicating some redundancy between the PKC isoforms. PKC? and PKC? had opposing effects on relative numbers of CD4+ and CD8+ T cells, because PKC??/? mice had a higher ratio of CD4+ to CD8+ T cells compared to that of wild-type mice, whereas PKC??/? mice had a lower ratio. In mice deficient in both PKC isoforms, the ratio of CD4+ to CD8+ T cells returned to normal. Together, these data suggest that whereas PKC? shares redundant roles with PKC? in T cell biology, it also performs nonredundant functions that are important for homeostasis and activation of T cells.

Fu, Guo; Hu, Jianfang; Niederberger-Magnenat, Nathalie; Rybakin, Vasily; Casas, Javier; Yachi, Pia P.; Feldstein, Stephanie; Ma, Bo; Hoerter, John A. H.; Ampudia, Jeanette; Rigaud, Stephanie; Lambolez, Florence; Gavin, Amanda L.; Sauer, Karsten; Cheroutre, Hilde; Gascoigne, Nicholas R. J.



HTLV-I viral escape and host genetic changes in the development of adult T cell leukemia.  


In the pathogenesis of adult T cell leukemia (ATL), an oncogenetic role of the human T cell lymphotropic virus type I (HTLV-I) Tax protein, viral escape from the host immune system, and host genetic changes have been proposed as contributory factors. We examined the premature stop codons in tax gene as one of the mutations that may lead to escape of HTLV-I from the cytotoxic T lymphocyte (CTL) response in HTLV-I carriers, to test whether a putative CTL escape mutant can emerge in the early stage of ATL development and whether HTLV-I infected cells with such a mutation can proliferate subsequently. We also examined deletion of cyclin-dependent kinase inhibitor 4 (INK4) genes and mutation of p53 gene in combination with changes in the HTLV-I genome in acute type ATL to test whether host genetic changes promoted the malignant transformation of ATL cells that carry putative CTL escape mutations. The premature stop codon in tax gene existed in many non-ATL HTLV-I carriers as a minor population but not in the commonest HTLV-I sequence of the individual. This minor population with a premature stop codon did not expand subsequently in 3 asymptomatic carriers tested. There were cases who had a mutation or deletion in HTLV-I who also have either deletion of INK4 genes or mutation in p53 gene. Our findings suggest that CTL escape mutation can occur at an early stage of ATL development, and that certain host genetic changes favor the development of the aggressive form of ATL. PMID:16052518

Furukawa, Yoshitaka; Tara, Mitsutoshi; Izumo, Shuji; Arimura, Kimiyoshi; Osame, Mitsuhiro



In Vitro Expanded CD4CD25Foxp3 Regulatory T Cells Maintain a Normal Phenotype and Suppress Immune-Mediated Ocular Surface Inflammation  

Microsoft Academic Search

PURPOSE. To determine whether in vitro expanded CD4CD25Foxp3 regulatory T cells can suppress immune- mediated ocular surface inflammation in a mouse model of dry eye. METHODS. C57BL\\/6 or BALB\\/c mice were exposed to a dry, desiccating environment produced by maintaining low humid- ity (40%), injections of scopolamine, and air flow produced by a fan. CD4CD25 regulatory T cells were isolated

Karyn F. Siemasko; Jianping Gao; Virginia L. Calder; Rebecca Hanna; Margarita Calonge; Stephen C. Pflugfelder; Jerry Y. Niederkorn; Michael E. Stern


IFN-? producing CD4+ T cells promote experimental cerebral malaria by modulating CD8+ T cell accumulation within the brain  

PubMed Central

It is well established that IFN-? is required for the development of experimental cerebral malaria (ECM) during Plasmodium berghei ANKA infection of C57BL/6 mice. To date, however, the temporal and tissue-specific cellular sources of IFN-? during P. berghei ANKA infection have not been investigated and it is not known if IFN-? production by a single cell type in isolation can induce cerebral pathology. In this study, using IFN-? reporter mice, we show that NK cells dominate the IFN-? response during the early stages of infection in the brain, but not in the spleen, before being replaced by CD4+ and CD8+ T cells. Importantly, we demonstrate that IFN-? producing CD4+ T cells, but not innate or CD8+ T cells, can promote the development of ECM in normally resistant IFN-??/? mice infected with P. berghei ANKA. Adoptively transferred wild-type (WT) CD4+ T cells accumulate within the spleen, lung and brain of IFN-??/? mice and induce ECM through active IFN-? secretion, which increases accumulation of endogenous IFN-??/? CD8+ T cells within the brain. Depletion of endogenous IFN-??/? CD8+ T cells abrogated the ability of WT CD4+ T cells to promote ECM. Finally we show that IFN-? production specifically by CD4+ T cells is sufficient to induce expression of CXCL9 and CXCL10 within the brain, providing a mechanistic basis for the enhanced CD8+ T cell accumulation. These observations demonstrate, for the first time, the importance of and pathways by which IFN-?-producing CD4+ T cells promote the development of ECM during P. berghei ANKA infection.

Villegas-Mendez, Ana; Greig, Rachel; Shaw, Tovah N.; de Souza, J. Brian; Findlay, Emily Gwyer; Stumhofer, Jason S.; Hafalla, Julius C. R.; Blount, Daniel G.; Hunter, Christopher A.; Riley, Eleanor M.; Couper, Kevin N.



Lymphoid tissue inducer cells maintain memory CD4 T cells within secondary lymphoid tissue  

PubMed Central

Phylogeny shows that CD4 T cell memory and lymph nodes (LNs) co-evolved in placental mammals. In ontogeny, retinoic acid orphan receptor (ROR) ?-dependent lymphoid tissue inducer (LTi) cells program the development of mammalian LNs. Here, we show that while primary CD4 T cell expansion is normal in ROR?-deficient mice, the persistence of memory CD4 T cells is ROR?-dependent. Furthermore, using bone marrow chimeric mice we demonstrate that LTi cells are the key ROR?-expressing cell type sufficient for memory CD4 T cell survival in the absence of persistent antigen. This effect was specific for CD4 T cells, since memory CD8 T cells survived equally well in the presence or absence of LTi cells. These data demonstrate a novel role for LTi cells, archetypal members of the innate lymphoid cell family, in supporting memory CD4 T cell survival in vivo.

Withers, David R.; Gaspal, Fabrina M.; Mackley, Emma C.; Marriott, Clare L.; Ross, Ewan A.; Desanti, Guillaume E.; Roberts, Natalie A.; White, Andrea J.; Flores-Langarica, Adriana; McConnell, Fiona M.; Anderson, Graham; Lane, Peter J.L.



Strong TCR Signaling, TLR Ligands, and Cytokine Redundancies Ensure Robust Development of Type 1 Effector T Cells1  

Microsoft Academic Search

T cell effector function is a central mechanism of adaptive immunity, and accordingly, protection of the host against pathogens. One of the primary effector molecules produced by T cells in response to such pathogens is the cytokine, IFN-. Although the signaling pathways associated with the production of IFN- are well established, disparate in vivo and in vitro results indicate that

Chiara Nembrini; Brian Abel; Manfred Kopf; Benjamin J. Marsland


Development of Epstein-Barr virus-specific memory T cell receptor clonotypes in acute infectious mononucleosis  

PubMed Central

The importance of cytotoxic T lymphocytes (CTLs) in the immunosurveillance of Epstein-Barr virus (EBV)-infected B cells is firmly established, and the viral antigens of CTL recognition in latent infection are well defined. The epitopes targeted by CTLs during primary infection have not been identified, however, and there is only limited information about T cell receptor (TCR) selection. In the present report, we have monitored the development of memory TCR-beta clonotypes selected in response to natural EBV infection in a longitudinal study of an HLA-B8+ individual with acute infectious mononucleosis (IM). By stimulating peripheral blood lymphocytes with HLA-B8+ EBV-transformed B lymphoblastoid cells, the primary virus- specific CTL response was shown to include specificities for two HLA-B8- restricted antigenic determinants, FLRGRAYGL and QAKWRLQTL, which are encoded within the latent EBV nuclear antigen EBNA-3. TCR-beta sequence analysis of CTL clones specific for each epitope showed polyclonal TCR- beta repertoire selection, with structural restrictions on recognition that indicated antigen-driven selection. Furthermore, longitudinal repertoire analysis revealed long-term preservation of a multiclonal effector response throughout convalescence, with the reemergence of distinct memory T cell clonotypes sharing similar structural restrictions. Tracking the progression of specific TCR-beta clonotypes and antigen-specific TCR-V beta family gene expression in the peripheral repertoire ex vivo using semiquantitative PCR strongly suggested that selective TCR-beta expansions were present at the clonotype level, but not at the TCR-V beta family level. Overall, in this first analysis of antigen-specific TCR development in IM, a picture of polyclonal TCR stimulation is apparent. This diversity may be especially important in the establishment of an effective CTL control during acute EBV infection and in recovery from disease.



Characterizing T-Cell Autoimmunity  

Microsoft Academic Search

\\u000a Immunological mechanisms which precipitate autoimmune diabetes involve the influence of a genetic footprint on the phenotype\\u000a of the T-cell response to self-antigens, and on development of pathological outcomes in immune responses resulting in T1D.\\u000a For one of the human diabetes antigens, proinsulin, recent findings allow the emergence of a model in which elements of genetically\\u000a biased T-cell development and peptide

Ivana Durinovic-Belló; Gerald T. Nepom


Thymic Epithelial Requirement for ?? T Cell Development Revealed in the Cell Ablation Transgenic System with TSCOT Promoter  

PubMed Central

In order to investigate the role of thymic epithelial cell (TEC) subsets during T-cell development, we established a new transgenic system, enabling inducible cell-specific ablation as well as marking the TEC subsets using bicistronic bacterial nitroreductase and EGFP genes. Two different lengths of the TSCOT promoter in transgenic mice, named 3.1T-NE and 9.1T-NE, drive EGFP expression into TECs. In adult life, EGFP expression was located in the medulla with a smaller 3.1 kb TSCOT promoter, while it was maintained in the cortex with a 9.1 kb promoter, suggesting putative TEC specific as well as compartment specific cis elements within two promoters. Nitroreductase induced cell death was specific without bystander killing upon the treatment of prodrugs such as nitrofurantoin and metronidazol. The degree of cell death was dependent on the dose of the prodrug in the cell and the fetal thymic organ cultures (FTOCs). Fetal thymic stromal populations were analyzed based on the expression levels of EpCAM, MHCII, CDR1 and/or UEA-1. EGFP expression patterns varied among subsets indicating the differential TSCOT promoter activity in each TEC subset. Prodrug treatment in FTOCs reduced the numbers of total and subsets of thymocytes. A CD4+CD8+ double positive cell population was highly susceptible in both transgenic lines. Surprisingly, there was a distinct reduction in ?? T cell population only in the 9.1T-NE thymus, indicating that they require a NTR-EGFP expressing TEC population. Therefore, these results support a division of labor within TEC subsets for the ?? and ?? lineage specification.

Lee, Gwanghee; Kim, Ki Yeon; Chang, Cheong-Hee; Kim, Moon Gyo



3-Hydroxykynurenine Suppresses CD4+ T-Cell Proliferation, Induces T-Regulatory-Cell Development, and Prolongs Corneal Allograft Survival  

PubMed Central

Purpose. IDO (indoleamine 2,3-dioxygenase) modulates the immune response by depletion of the essential amino acid tryptophan, and IDO overexpression has been shown to prolong corneal allograft survival. This study was conducted to examine the effect of kynurenines, the products of tryptophan breakdown and known to act directly on T lymphocytes, on corneal graft survival. Methods. The effects of kynurenines on T-cell proliferation and death, T-regulatory-cell development, and dendritic cell function, phenotype, and viability were analyzed in vitro. The effect of topical and systemic administration of 3-hydroxykynurenine (3HK) on orthotopic murine corneal allograft survival was examined. Results. T-lymphocyte proliferation was inhibited by two of the four different kynurenines: 3HK and 3-hydroxyanthranilic acid (3HAA). This effect was accompanied by significant T-cell death. Neither 3HK nor 3HAA altered dendritic cell function, nor did they induce apoptosis or pathogenicity to corneal endothelial cells. Administration of systemic and topical 3HK to mice receiving a fully mismatched corneal graft resulted in significant prolongation of graft survival (median survival of control grafts, 12 days; of treated, 19 and 15 days, respectively; P < 0.0003). While systemic administration of 3HK was associated with a significant depletion of CD4+ T, CD8+ T, and B lymphocytes in peripheral blood, no depletion was found after topical administration. Conclusions. The production of kynurenines, in particular 3HK and 3HAA, may be one mechanism (in addition to tryptophan depletion) by which IDO prolongs graft survival. These molecules have potential as specific agents for preventing allograft rejection in patients at high rejection risk.

Zaher, Sarah S.; Germain, Conrad; Fu, Hongmei; Larkin, Daniel F. P.



Neonatal CD8+ T cells are slow to develop into lytic effectors after HSV infection in vivo.  


HSV is an important neonatal pathogen. We defined the kinetics of the primary CTL response to HSV-2 in vivo in neonatal mice. Using a replication-defective HSV-2 virus, we demonstrate that neonates mount a primary HSV-specific CTL effector response in the draining LN, with delayed onset and shortened peak activity, in contrast to the rapid, strong response observed in adult mice. The shortened peak neonatal CTL response is independent of HSV dose and is associated with retarded CD8(+) T cell expansion, reduced expansion of HSV-specific tetramer-positive CD8(+) T cells and a reduced CD8(+) T cell IFN-gamma response. Paradoxically, neonatal CD8(+) T cells display enhanced non-specific early activation that is not sustained. Neonatal HSV-specific TCR-transgenic CD8(+) T cells showed reduced proliferation in vivo when transferred into HSV-infected neonatal mice compared to adult T cell controls. Our data suggest that early events in CD8(+) T cell priming underlie the attenuated newborn CTL response to HSV. PMID:18081035

Fernandez, Marian A; Evans, Ingrid A C; Hassan, Eddy H; Carbone, Francis R; Jones, Cheryl A



Critical roles of the PI3K\\/Akt signaling pathway in T cell development  

Microsoft Academic Search

Thymocyte development requires an integration of extracellular cues to enforce lineage commitment at multiple defined checkpoints in a stage-specific manner. Critical signals from the pre-TCR, Notch, and the receptor for interleukin-7 (IL-7) dictate cellular differentiation from the CD4?CD8? (double negative) stage to the CD4+CD8+ (double positive) stage. The PI3K\\/Akt signaling pathway is required to translate these extracellular signaling events into

Marisa M. Juntilla; Gary A. Koretzky



T cell immune reconstitution following lymphodepletion  

Microsoft Academic Search

T cell reconstitution following lymphopenia from chemotherapy or stem cell transplant is often slow and incompetent, contributing to the development of infectious diseases, relapse, and graft-versus-host disease. This is due to the fact that de novo T cell production is impaired following cytoreductive regimens. T cells can be generated from two pathways: (1) thymus derived through active thymopoiesis and (2)

Kirsten M. Williams; Frances T. Hakim; Ronald E. Gress



Role of SMAD and Non-SMAD Signals in the Development of Th17 and Regulatory T Cells  

PubMed Central

Whereas TGF-? is essential for the development of peripherally induced Foxp3+ regulatory T cells (iTreg cells) and Th17 cells, the intracellular signaling mechanism by which TGF-? regulates development of both cell subsets is less understood. In this study, we report that neither Smad2 nor Smad3 gene deficiency abrogates TGF-?–dependent iTreg induction by a deacetylase inhibitor trichostatin A in vivo, although the loss of the Smad2 or Smad3 gene partially reduces iTreg induction in vitro. Similarly, SMAD2 and SMAD3 have a redundant role in development of Th17 in vitro and in experimental autoimmune encephalomyelitis. In addition, ERK and/or JNK pathways were shown to be involved in regulating iTreg cells, whereas the p38 pathway predominately modulated Th17 and experimental autoimmune encephalomyelitis induction. Therefore, selective targeting of these intracellular TGF-? signaling pathways during iTreg and Th17 cell development might lead to the development of therapies in treating autoimmune and other chronic inflammatory diseases.

Lu, Ling; Wang, Julie; Zhang, Feng; Chai, Yang; Brand, David; Wang, Xuehao; Horwitz, David A.; Shi, Wei; Zheng, Song Guo



Unsuspected role for the T-cell leukemia protein SCL/tal-1 in vascular development  

PubMed Central

The transcription factor SCL/tal-1 is essential for blood cell development. Though it is also expressed in vascular endothelium, SCL has been considered dispensable for vessel formation. Through transgenic rescue of hematopoietic defects of SCL?/? embryos and analysis of chimeras generated with SCL?/? ES cells tagged with a transgene expressed in vascular endothelial cells, we show that SCL is essential for angiogenic remodeling of the yolk sac capillary network into complex vitelline vessels. These findings establish a role for SCL in embryonic angiogenesis and argue for critical functions in both embryonic blood and vascular cells, the descendents of the presumptive hemangioblast.

Visvader, Jane E.; Fujiwara, Yuko; Orkin, Stuart H.



Induced and natural regulatory T cells in the development of inflammatory bowel disease.  


The mucosal immune system mediates contact between the host and the trillions of microbes that symbiotically colonize the gastrointestinal tract. Failure to tolerate the antigens within this "extended self" can result in inflammatory bowel disease (IBD). Within the adaptive immune system, the most significant cells modulating this interaction are Foxp3 regulatory T (Treg) cells. Treg cells can be divided into 2 primary subsets: "natural" Treg cells and "adaptive" or "induced" Treg. Recent research suggests that these subsets serve to play both independent and synergistic roles in mucosal tolerance. Studies from both mouse models and human patients suggest that defects in Treg cells can play distinct causative roles in IBD. Numerous genetic, microbial, nutritional, and environmental factors that associate with IBD may also affect Treg cells. In this review, we summarize the development and function of Treg cells and how their regulatory mechanisms may fail, leading to a loss of mucosal tolerance. We discuss both animal models and studies of patients with IBD suggesting Treg cell involvement in IBD and consider how Treg cells may be used in future therapies. PMID:23656897

Mayne, Christopher G; Williams, Calvin B



Inhibition of transmethylation down-regulates CD4 T cell activation and curtails development of autoimmunity in a model system.  


Transmethylation affects several cellular events, including T cell activation, and blockade of this pathway may curtail inflammatory/autoimmune responses. Here, we demonstrate that transmethylation inhibition by a novel reversible S-adenosyl-l-homocysteine hydrolase inhibitor leads to immunosuppression by reducing phosphorylation of several key proteins involved in TCR signaling, including Akt, Erk1/2, and NF-kappaB. Remarkably, this effect was largely restricted to CD4 T cells and correlated with reduced arginine methylation of Vav1, an essential guanine nucleotide exchange factor in T cell stimulation. Treatment with the transmethylation inhibitor averted, and even ameliorated, the CD4-mediated autoimmune disease, experimental autoimmune encephalomyelitis. The data suggest that transmethylation is required for CD4 T cell activation, and its inhibition may be a novel approach in the treatment of multiple sclerosis, and other CD4-mediated autoimmune diseases. PMID:17404322

Lawson, Brian R; Manenkova, Yulia; Ahamed, Jasimuddin; Chen, Xiaoru; Zou, Jian-Ping; Baccala, Roberto; Theofilopoulos, Argyrios N; Yuan, Chong



From the Cover: Functional CD8+ but not CD4+ T cell responses develop independent of thymic epithelial MHC  

Microsoft Academic Search

The role of nonthymic epithelial (non-TE) MHC in T cell repertoire selection remains controversial. To analyze the relative roles of thymic epithelial (TE) and non-TE MHC in T cell repertoire selection, we have generated tetraparental aggregation chimeras (B6-nudeBALB\\/c and B6BALB\\/c-nude) harboring T and B cells from both parents, whereas TE cells originated exclusively from the non-nude donor. These chimeras mounted

Marianne M. Martinic; Maries F. van den Broek; Thomas Rülicke; Christoph Huber; Bernhard Odermatt; Walter Reith; Raphael Zellweger; Katja Fink; Mike Recher; Bruno Eschli; Hans Hengartner; Rolf M. Zinkernagel



H1521, a novel derivative of 4-hydroxyquinoline-3-carboxamide, suppresses the development of lupus in mice by inducing Th1 cytokine profile in T cells.  


Transferring parental splenocytes into unirradiated F1 mice induces a chronic graft-versus-host disease (GVHD), characterized by the production of Th2 cytokines and immunocomplex-mediated glomerulonephritis resembling systemic lupus erythematosus (SLE). The effects of H1521, a new derivative of 4-hydroxyquinoline-3-carboxamide, were investigated in chronic GVHD lupus model. H1521 was administered to chronic GVHD mice for 10 weeks. Nephritic symptoms were monitored and cytokine expression in the spleen was detected. To clarify the direct effect of H1521 on CD4(+) T cell, CD4(+) T cells were isolated and co-cultured with H1521 under neutral and Th1 or Th2 driving conditions in vitro. H1521 (32 mg/kg) reduced the incidence of proteinuria by 50% in chronic GVHD mice. Ameliorated lupus symptoms and improved renal histopathology damage were also observed. Administration of H1521 had little impact on Th1 cytokine IL-2 and IFN-gamma or Th2 cytokine IL-4 and IL-10 mRNA expression. In contrast, severely deficient IFN-gamma production by concanavalin A-stimulated spleen cells in chronic GVHD mice was completely restored by H1521. In accordance with this, decreased T-bet mRNA expression became normalized with H1521 (32 mg/kg) treatment. In addition, in vitro studies demonstrated that H1521 preferentially favored Th1 differentiation in CD4(+) T cell and promoted IFN-gamma secretion in Th1 differential CD4(+) T cell. However, IL-4 secretion in naive or Th2 differential CD4(+) T cell was unaffected by H1521. In conclusion, H1521 can induce Th1 cytokine profile in CD4(+) T cells and has possible therapeutic value in Th2-predominant immune diseases. PMID:21195814

Xiao, Zhi-yong; Chen, Shao-hui; Zhou, Wen-xia; Zhang, Yong-xiang; Cheng, Jun-peng; Yang, Ri-fang



Preferential tissue localization of bovine ?? T cell subsets defined by anti-T cell receptor for antigen antibodies  

Microsoft Academic Search

Clonal and oligoclonal populations of ?? T cells, with respect to the expression of T cell receptors for antigen (Tcr), have been shown to localize in normal and inflamed tissues. The mechanisms responsible for the tissue-selective accumulation of these subsets are still not known. ?? T cells are the predominant T cell subset in newborn calves, making this animal a

E Wilson; B Walcheck; W. C Davis; M. A Jutila



Modulation of T cell development and activation by novel members of the Schlafen (slfn) gene family harbouring an RNA helicase-like motif  

Microsoft Academic Search

The regulatory networks governing development and differentiation of hematopoietic cells are incompletely understood. Members of the Schlafen (Slfn) protein family have been implicated in the regulation of cell growth and T cell development. We have identified and chromosomally mapped four new members, slfn5, slfn8, slfn9 and slfn10, which belong to a distinct subgroup within this gene family. The characteristic feature

Peter Geserick; Frank Kaiser; Uwe Klemm; Stefan H. E. Kaufmann; Jens Zerrahn



?? T cells enhance autoimmunity by restraining regulatory T cell responses via an interleukin-23 dependent mechanism  

PubMed Central

Summary Mice that lack interleukin-23 (IL-23) are resistant to T cell-mediated autoimmunity. Although IL-23 is a maturation factor for T helper 17 (Th17) cells, a subset of ?? T cells expresses the IL-23 receptor (IL-23R) constitutively. Using IL-23R reporter mice, we showed that ?? T cells were the first cells to respond to IL-23 during experimental autoimmune encephalomyelitis (EAE). Although ?? T cells produced Th17 cell-associated cytokines in response to IL-23, their major function was to prevent the development of regulatory T (Treg) cell responses. IL-23-activated ?? T cells rendered ?? effector T cells refractory to the suppressive activity of Treg cells and also prevented the conversion of conventional T cells into Foxp3+ Treg cells in vivo. Thus, IL-23, which by itself has no direct effect on Treg cells, is able to disarm Treg cell responses and promote antigen specific effector T cell responses via activating ?? T cells.

Petermann, Franziska; Rothhammer, Veit; Claussen, Malte C.; Haas, Jan D.; Riol Blanco, Lorena; Heink, Sylvia; Prinz, Immo; Hemmer, Bernhard; Kuchroo, Vijay K.; Oukka, Mohamed; Korn, Thomas



Initial T cell frequency dictates memory CD8+ T cell lineage commitment  

PubMed Central

Memory T cells can be divided into central memory T cell (TCM cell) and effector memory T cell (TEM cell) subsets based on homing characteristics and effector functions. Whether TEM and TCM cells represent interconnected or distinct lineages is unclear, although the present paradigm suggests that TEM and TCM cells follow a linear differentiation pathway from naive T cells to effector T cells to TEM cells to TCM cells. We show here that naive T cell precursor frequency profoundly influenced the pathway along which CD8+ memory T cells developed. At low precursor frequency, those TEM cells generated represented a stable cell lineage that failed to further differentiate into TCM cells. These findings do not adhere to the present dogma regarding memory T cell generation and provide a means for identifying factors controlling memory T cell lineage commitment.

Marzo, Amanda L; Klonowski, Kimberly D; Le Bon, Agnes; Borrow, Persephone; Tough, David F; Lefrancois, Leo



Poor Predictive Value of Cytomegalovirus (CMV)-Specific T Cell Assays for the Development of CMV Retinitis in Patients with AIDS  

PubMed Central

Background We examined the potential clinical utility of using a cytomegalovirus (CMV)–specific T cell immunoassay to determine the risk of developing new-onset CMV retinitis (CMVR) in patients with acquired immunodeficiency syndrome (AIDS). Methods CMV-specific T cell assays were performed by multiparameter flow cytometry using stored peripheral blood mononuclear cells that had been obtained in an observational study 2–6 months before new-onset CMVR was diagnosed in case patients (at a study visit during which a dilated ophthalmologic examination revealed no evidence of CMVR) and at the same study visit in control subjects (matched by absolute CD4+ T cell count at entry) who did not subsequently develop retinitis during 1–6 years of study follow-up. Results There were no significant differences in CMV-specific CD4+ or CD8+ T cell interferon-? or interleukin-2 expression in peripheral blood mononuclear cells from case patients and control subjects. Although there were trends toward lower percentages and absolute numbers of CMV-specific, cytokine-expressing CD8+ T cells with a “late memory” phenotype (CD27?CD28?) as well as with an “early memory” phenotype (CD27+CD28+CD45RA+) in case patients than in control subjects, these differences were not statistically significant. Conclusions Many studies have reported that CMV-specific CD4+ and CD8+ T cell responses distinguish patients with active CMVR (i.e., who lack CMV-protective immunity) from those with inactive CMVR after immune restoration by antiretroviral treatment (i.e., who have CMV-protective immunity). However, the multiple CMV-specific immune responses we measured do not appear to have clinical utility for predicting the risk for patients with AIDS of developing new-onset CMVR with sufficient accuracy to be used in guiding therapeutic management.

Jacobson, Mark A.; Tan, Qi Xuan; Girling, Valerie; Poon, C.; Van Natta, Mark; Jabs, Douglas A.; Inokuma, Margaret; Maecker, Holden T.; Bredt, Barry; Sinclair, Elizabeth



Effects of Postchallenge Administration of ST-246 on Dissemination of IHD-J-Luc Vaccinia Virus in Normal Mice and in Immune-Deficient Mice Reconstituted with T Cells  

PubMed Central

Whole-body bioimaging was used to study dissemination of vaccinia virus (VACV) in normal and in immune deficient (nu?/nu?) mice protected from lethality by postchallenge administration of ST-246. Total fluxes were recorded in the liver, spleen, lungs, and nasal cavities of live mice after intranasal infection with a recombinant IHD-J-Luc VACV expressing luciferase. Areas under the flux curve were calculated for individual mice to assess viral loads. Treatment for 2 to 5 days of normal BALB/c mice with ST-246 at 100 mg/kg starting 24 h postchallenge conferred 100% protection and reduced viral loads in four organs compared to control mice. Mice also survived after 5 days of treatment with ST-246 at 30 mg/kg, and yet the viral loads and poxes were higher in these mice compared to 100-mg/kg treatment group. Nude mice were not protected by ST-246 alone or by 10 million adoptively transferred T cells. In contrast, nude mice that received T cells and 7-day treatment with ST-246 survived infection and exhibited reduced viral loads compared to nonreconstituted and ST-246-treated mice after ST-246 was stopped. Similar protection of nude mice was achieved using adoptively transferred 1.0 and 0.1 million, but not 0.01 million, purified T cells or CD4+ or CD8+ T cells in conjunction with ST-246 treatment. These data suggest that ST-246 protects immunocompetent mice from lethality and reduces viral dissemination in internal organs and poxvirus lesions. Furthermore, immune-deficient animals with partial T cell reconstitution can control virus replication after a course of ST-246 and survive lethal vaccinia virus challenge.

Shotwell, Elisabeth; Scott, John; Cruz, Stephanie; King, Lisa R.; Manischewitz, Jody; Diaz, Claudia G.; Jordan, Robert A.; Grosenbach, Douglas W.; Golding, Hana



NFAT5 induction by the pre-T-cell receptor serves as a selective survival signal in T-lymphocyte development  

PubMed Central

The Rel-like transcription factors nuclear factor kappa B (NF-?B) and the calcineurin-dependent nuclear factor of activated T cells (NFATc) control specific points of thymocyte maturation. Thymocytes also express a distinct member of the Rel family, the calcineurin-independent, osmostress response regulator NFAT5. Here we show that IKK? regulates the expression of NFAT5 in thymocytes, which in turn contributes to the survival of T-cell receptor ?? thymocytes and the transition from the ?-selection checkpoint to the double-positive stage in an osmostress-independent manner. NFAT5-deficient thymocytes had normal expression and proximal signaling of the pre–T-cell receptor but exhibited a partial defect in ?-chain allelic exclusion and increased apoptosis. Further analysis showed that NFAT5 regulated the expression of the prosurvival factors A1 and Bcl2 and attenuated the proapoptotic p53/Noxa axis. These findings position NFAT5 as a target of the IKK?/NF-?B pathway in thymocytes and as a downstream effector of the prosurvival role of the pre–T-cell receptor.

Berga-Bolanos, Rosa; Alberdi, Maria; Buxade, Maria; Aramburu, Jose; Lopez-Rodriguez, Cristina



High-scatter T cells: a reliable biomarker for malignant T cells in cutaneous T-cell lymphoma  

PubMed Central

In early-stage cutaneous T-cell lymphoma (CTCL), malignant T cells are confined to skin and are difficult to isolate and discriminate from benign reactive cells. We found that T cells from CTCL skin lesions contained a population of large, high-scatter, activated skin homing T cells not observed in other inflammatory skin diseases. High-scatter T (THS) cells were CD4+ in CD4+ mycosis fungoides (MF), CD8+ in CD8+ MF, and contained only clonal T cells in patients with identifiable malignant V? clones. THS cells were present in the blood of patients with leukemic CTCL, absent in patients without blood involvement, and contained only clonal malignant T cells. The presence of clonal THS cells correlated with skin disease in patients followed longitudinally. Clonal THS cells underwent apoptosis in patients clearing on extracorporeal photopheresis but persisted in nonresponsive patients. Benign clonal T-cell proliferations mapped to the normal low-scatter T-cell population. Thus, the malignant T cells in both MF and leukemic CTCL can be conclusively identified by a unique scatter profile. This observation will allow selective study of malignant T cells, can be used to discriminate patients with MF from patients with other inflammatory skin diseases, to detect peripheral blood involvement, and to monitor responses to therapy.

Shackelton, Jeffrey B.; Watanabe, Rei; Calarese, Adam; Yamanaka, Kei-ichi; Campbell, James J.; Teague, Jessica E.; Kuo, Helen P.; Hijnen, DirkJan; Kupper, Thomas S.



Longitudinal Analysis of the Human T Cell Response during Acute Hantavirus Infection ? †  

PubMed Central

Longitudinal studies of T cell immune responses during viral infections in humans are essential for our understanding of how effector T cell responses develop, clear infection, and provide long-lasting immunity. Here, following an outbreak of a Puumala hantavirus infection in the human population, we longitudinally analyzed the primary CD8 T cell response in infected individuals from the first onset of clinical symptoms until viral clearance. A vigorous CD8 T cell response was observed early following the onset of clinical symptoms, determined by the presence of high numbers of Ki67+CD38+HLA-DR+ effector CD8 T cells. This response encompassed up to 50% of total blood CD8 T cells, and it subsequently contracted in parallel with a decrease in viral load. Expression levels of perforin and granzyme B were high throughout the initial T cell response and likewise normalized following viral clearance. When monitoring regulatory components, no induction of regulatory CD4 or CD8 T cells was observed in the patients during the infection. However, CD8 as well as CD4 T cells exhibited a distinct expression profile of inhibitory PD-1 and CTLA-4 molecules. The present results provide insight into the development of the T cell response in humans, from the very onset of clinical symptoms following a viral infection to resolution of the disease.

Lindgren, Therese; Ahlm, Clas; Mohamed, Nahla; Evander, Magnus; Ljunggren, Hans-Gustaf; Bjorkstrom, Niklas K.



Longitudinal analysis of the human T cell response during acute hantavirus infection.  


Longitudinal studies of T cell immune responses during viral infections in humans are essential for our understanding of how effector T cell responses develop, clear infection, and provide long-lasting immunity. Here, following an outbreak of a Puumala hantavirus infection in the human population, we longitudinally analyzed the primary CD8 T cell response in infected individuals from the first onset of clinical symptoms until viral clearance. A vigorous CD8 T cell response was observed early following the onset of clinical symptoms, determined by the presence of high numbers of Ki67(+)CD38(+)HLA-DR(+) effector CD8 T cells. This response encompassed up to 50% of total blood CD8 T cells, and it subsequently contracted in parallel with a decrease in viral load. Expression levels of perforin and granzyme B were high throughout the initial T cell response and likewise normalized following viral clearance. When monitoring regulatory components, no induction of regulatory CD4 or CD8 T cells was observed in the patients during the infection. However, CD8 as well as CD4 T cells exhibited a distinct expression profile of inhibitory PD-1 and CTLA-4 molecules. The present results provide insight into the development of the T cell response in humans, from the very onset of clinical symptoms following a viral infection to resolution of the disease. PMID:21795350

Lindgren, Therese; Ahlm, Clas; Mohamed, Nahla; Evander, Magnus; Ljunggren, Hans-Gustaf; Björkström, Niklas K



Antigen-independent development of Foxp3+ regulatory T cells suppressing autoantibody production in experimental pemphigus vulgaris.  


The CD4(+)CD25(+)Foxp3(+) regulatory T cells (Tregs) play suppressive roles in various types of autoimmunity. It has been reported that Tregs develop in the thymus after high-affinity interaction of their TCR with self-peptide/MHC ligands mostly utilizing TCR-transgenic system. In this study, we examined whether the specific antigen is involved in the development of polyclonal Tregs in pemphigus vulgaris (PV), an autoimmune blistering disease caused by anti-desmoglein 3 (Dsg3) IgG antibodies, as a model system. Adoptive transfer of splenocytes of Dsg3(-)(/-) mice immunized with recombinant mouse Dsg3 to Rag2(-)(/-) recipient mice expressing Dsg3 resulted in the stable production of anti-Dsg3 IgG and the development of PV phenotypes. We show here that Tregs control anti-Dsg3 antibody production in PV model mice: the adoptive transfer of Tregs and the depletion of endogenous Tregs suppressed and augmented, respectively, the anti-Dsg3 antibody production. To examine whether the endogenous expression of Dsg3 is involved in the generation of these PV-relevant Tregs, we compared the potential of wild-type Tregs with that of Tregs from Dsg3(-)(/-) mice. Polyclonal Tregs from Dsg3(-)(/-) mice were more potent than that of wild-type mice, in both adoptive transfer and Treg-depletion experiments, while suppressive activities against IgG production against an irrelevant antigen were similar between Tregs from wild-type and Dsg3(-)(/-) mice. Our observation implies that Tregs capable of suppressing T(h) cells that drive autoantibody production can develop in the absence of the target antigen. PMID:21525154

Yokoyama, Tomoaki; Matsuda, Satoshi; Takae, Yujiro; Wada, Naoko; Nishikawa, Takeji; Amagai, Masayuki; Koyasu, Shigeo



Interleukin-2, -7 and -15, but not TSLP, Redundantly Govern CD4+Foxp3+ Regulatory T Cell Development1  

PubMed Central

Common ? chain (?c)-receptor dependent cytokines are required for regulatory T cell (Treg) development as ?c?/? mice lack Tregs. However, it is unclear which ?c-dependent cytokines are involved in this process. Furthermore, TSLP has also been suggested to play a role in Treg development. Herein, we demonstrate that developing CD4+Foxp3+ Tregs in the thymus express the IL2R?, IL4R?, IL7R?, IL15R? and IL21R? chains, but not the IL9R? or TSLPR? chains. Moreover, only IL2, and to a much lesser degree IL7 and IL15, were capable of transducing signals in CD4+Foxp3+ Tregs as determined by monitoring STAT5 phosphorylation. Likewise, IL2, IL7 and IL15, but not TSLP, were capable of inducing the conversion of CD4+CD25+Foxp3? thymic Treg progenitors into CD4+Foxp3+ mature Tregs in vitro. To examine this issue in more detail we generated IL2R??/? x IL7R??/? and IL2R??/? x IL4R??/? mice. We found that IL2R??/? x IL7R??/? mice were devoid of Tregs thereby recapitulating the phenotype observed in ?c?/? mice; in contrast, the phenotype observed in IL2R??/? x IL4R??/? mice was comparable to that seen in IL2R??/? mice. Finally, we observed that Tregs from both IL2?/? and IL2R??/? mice show elevated expression of IL7R? and IL15R? chains. Addition of IL2 to Tregs from IL2?/? mice led to rapid downregulation of these receptors. Taken together, our results demonstrate that IL2 plays the predominant role in Treg development, but that in its absence the IL7R? and IL15R? chains are upregulated and allow for IL7 and IL15 to partially compensate for loss of IL2.

Vang, Kieng B.; Yang, Jianying; Mahmud, Shawn A.; Burchill, Matthew A.; Vegoe, Amanda L.; Farrar, Michael A.



B cells help alloreactive T cells differentiate into memory T cells1  

PubMed Central

B cells are recognized as effector cells in allograft rejection that are dependent upon T cell help to produce alloantibodies causing graft injury. It is not known if B cells can also help T cells differentiate into memory cells in the alloimmune response. We found that in B cell-deficient hosts, differentiation of alloreactive T cells into effectors was intact whereas their development into memory T cells was impaired. To test if B cell help for T cells was required for their continued differentiation into memory T cells, activated T cells were sorted from alloimmunized mice and transferred either with or without B cells into naïve adoptive hosts. Activated T cells co-transferred with B cells gave rise to more memory T cells than those transferred without B cells and upon recall, mediated accelerated rejection of skin allografts. Co-transfer of B cells led to increased memory T cells by enhancing activated CD4 T cell proliferation and activated CD8 T cell survival. These results indicate that B cells help alloreactive T cell differentiation, proliferation and survival to generate optimal numbers of functional memory T cells.

Ng, Yue-Harn; Oberbarnscheidt, Martin H.; Chandramoorthy, Harish Chinna Konda; Hoffman, Rosemary; Chalasani, Geetha



Lineage-specific effects of 1,25-dihydroxyvitamin D(3) on the development of effector CD4 T cells.  


Vitamin D deficiency is implicated in autoimmune disease. We therefore evaluated the effects of 1?,25-dihydroxyvitamin D(3) (1,25-D(3)), the active form of vitamin D, on the development of T helper 1 (Th1), Th17, and Th9 cells, which are implicated in the pathogenesis of different types of autoimmunity. 1,25-D(3) compromised the development of Th17 and Th9 cells, including IL-22-expressing cells while simultaneously increasing the frequency of IL-10-competent cells. Relative to Th17 and Th9 cells, the effects of 1,25-D(3) on Th1 cells were modest, reflecting the significantly reduced levels of the receptor for vitamin D in this lineage. The use of cells deficient in IL-10 or antibodies that block IL-10 signaling abolished the inhibitory effect of 1,25-D(3) on Th9 cells but had no effect on inhibition of Th17 cell frequencies. Thus, the induction of IL-10 in cultures of Th9 cells is an important mechanism by which 1,25-D(3) compromises Th9 development but does not explain inhibition of Th17 cells. A survey of select representatives of the Th17 transcriptome revealed that the levels of mRNA that encode ROR?t, IL-17A, IL-17F, IL-23R, and IL-22, were reduced by 1,25-D(3), whereas IL-21 and aryl hydrocarbon receptor mRNA remained unchanged. These data suggest that vitamin D deficiency may promote autoimmunity by favoring the inordinate production of Th17 and Th9 cells at the expense of regulatory IL-10-producing T cells. PMID:21047796

Palmer, Matthew T; Lee, Yun Kyung; Maynard, Craig L; Oliver, James R; Bikle, Daniel D; Jetten, Anton M; Weaver, Casey T



T Cell-Dendritic Cell Interaction in Vivo: Random Encounters Favor Development of Long-Lasting Ties  

NSDL National Science Digital Library

Understanding the complexity of the functional communication between cells composing the immune system is central to improving our capacity to manipulate it and conceive better strategies to combat microbial pathogens. So far, these studies have been based on immunohistochemistry of fixed tissues and in vitro attempts to reproduce functional connections between cells. The application of two-photon laser microscopy to the observation of viable immune cells in their natural environment where foreign antigens are carried to trigger an immune response opens a new era for these studies. They reveal exceptional properties of the locomotion of T cells that facilitate encounters with dendritic cells and the receipt of information that promotes T cell survival, death, or initiation of immune responses. These studies also complement in vitro observations addressing the importance of time of stimulation in determining T cell fates.

Oreste Acuto (Institut Pasteur;Molecular Immunology Unit, Department of Immunology REV)



Immunologic self-tolerance maintained by CD25+CD4+ naturally anergic and suppressive T cells: induction of autoimmune disease by breaking their anergic\\/suppressive state  

Microsoft Academic Search

Elimination of CD25 F T cells, which constitute 5-10% of peripheral CD4 F T cells in normal naive mice, leads to spontaneous development of various autoimmune diseases. These immunoregulatory CD25 F CD4 F T cells are naturally unresponsive (anergic) in vitro to TCR stimulation, and, upon stimulation, suppress proliferation of CD25 - CD4 F T cells and CD8 F T

Takeshi Takahashi; Yuhshi Kuniyasu; Masaaki Toda; Noriko Sakaguchi; Misako Itoh; Makoto Iwata; Jun Shimizu; Shimon Sakaguchi



HLA-E-restricted regulatory CD8+ T cells are involved in development and control of human autoimmune type 1 diabetes  

PubMed Central

A key feature of the immune system is its ability to discriminate self from nonself. Breakdown in any of the mechanisms that maintain unresponsiveness to self (a state known as self-tolerance) contributes to the development of autoimmune conditions. Recent studies in mice show that CD8+ T cells specific for the unconventional MHC class I molecule Qa-1 bound to peptides derived from the signal sequence of Hsp60 (Hsp60sp) contribute to self/nonself discrimination. However, it is unclear whether they exist in humans and play a role in human autoimmune diseases. Here we have shown that CD8+ T cells specific for Hsp60sp bound to HLA-E (the human homolog of Qa-1) exist and play an important role in maintaining peripheral self-tolerance by discriminating self from nonself in humans. Furthermore, in the majority of type 1 diabetes (T1D) patients tested, there was a specific defect in CD8+ T cell recognition of HLA-E/Hsp60sp, which was associated with failure of self/nonself discrimination. However, the defect in the CD8+ T cells from most of the T1D patients tested could be corrected in vitro by exposure to autologous immature DCs loaded with the Hsp60sp peptide. These data suggest that HLA-E–restricted CD8+ T cells may play an important role in keeping self-reactive T cells in check. Thus, correction of this defect could be a potentially effective and safe approach in the therapy of T1D.

Jiang, Hong; Canfield, Steve M.; Gallagher, Mary P.; Jiang, Hong H.; Jiang, Yihua; Zheng, Zongyu; Chess, Leonard



Bach2 maintains T cells in a naive state by suppressing effector memory-related genes.  


The transcriptional repressor BTB and CNC homology 2 (Bach2) is thought to be mainly expressed in B cells with specific functions such as class switch recombination and somatic hypermutation, but its function in T cells is not known. We found equal Bach2 expression in T cells and analyzed its function using Bach2-deficient (-/-) mice. Although T-cell development was normal, numbers of peripheral naive T cells were decreased, which rapidly produced Th2 cytokines after TCR stimulation. Bach2(-/-) naive T cells highly expressed genes related to effector-memory T cells such as CCR4, ST-2 and Blimp-1. Enhanced expression of these genes induced Bach2(-/-) naive T cells to migrate toward CCR4-ligand and respond to IL33. Forced expression of Bach2 restored the expression of these genes. Using Chromatin Immunoprecipitation (ChIP)-seq analysis, we identified S100 calcium binding protein a, Heme oxigenase 1, and prolyl hydroxylase 3 as Bach2 direct target genes, which are highly expressed in effector-memory T cells. These findings indicate that Bach2 suppresses effector memory-related genes to maintain the naive T-cell state and regulates generation of effector-memory T cells. PMID:23754397

Tsukumo, Shin-ichi; Unno, Midori; Muto, Akihiko; Takeuchi, Arata; Kometani, Kohei; Kurosaki, Tomohiro; Igarashi, Kazuhiko; Saito, Takashi



A critical role for STAT3 transcription factor signaling in the development and maintenance of human T cell memory  

PubMed Central

Summary STAT3 transcription factor signaling in specific T helper cell differentiation have been well described, whereas the broader roles for STAT3 in lymphocyte memory are less clear. Patients with autosomal dominant hyper-IgE syndrome (AD-HIES) carry dominant negative STAT3 mutations and are susceptible to a variety of bacterial and fungal infections. We found that AD-HIES patients have a cell-intrinsic defect in the number of central memory CD4+ and CD8+ T cells compared to healthy controls. Naïve T cells from AD-HIES patients had lower expression of memory-related transcription factors BCL6 and SOCS3, a primary proliferation defect, and they failed to acquire central memory-like surface phenotypes in vitro. AD-HIES patients showed a decreased ability to control varicella zoster virus (VZV) and Epstein-Barr virus (EBV) latency, and T cell memory to both of these viruses was compromised. These data point to a specific role for STAT3 in human central memory T cell formation and in control of certain chronic viruses.

Siegel, Andrea M.; Heimall, Jennifer; Freeman, Alexandra F.; Hsu, Amy P.; Brittain, Erica; Brenchley, Jason M.; Douek, Daniel C.; Fahle, Gary H.; Cohen, Jeffrey I.; Holland, Steven M.; Milner, Joshua D.



Development of a procedure for the direct cloning of T-cell epitopes using bacterial expression systems  

Microsoft Academic Search

Although single bacterial recombinant antigens have been used successfully to stimulate individual T-cell clones and elicit recall responses in peripheral lymphocytes, the broader use of molecular cloning systems for the identification of autoantigens recognised by the cellular arm of the immune system has met with only limited success. In a systematic approach to address this problem, a series of bacterial

Pavlos I. Neophytou; Patricia Ozegbe; Donald Healey; Ruby Quartey-Papafio; Anne Cooke; John C. Hutton



Regulatory T cells.  


Regulatory T (TR) cells are a subset of T cells that function to control immune responses. Different populations of TR cells have been described, including thymically derived CD4(+)CD25+ TR cells and Tr1 cells induced in the periphery through exposure to antigen. A transcription factor, Foxp3, has been identified that is essential for CD4(+)CD25+ TR cell development and function. There is now evidence that transforming growth factor-beta might play a role in this pathway. CD4(+)CD25+ TR cells proliferate extensively in vivo in an antigen-specific manner, and can respond to both self and foreign peptides. By suppressing excessive immune responses, TR cells play a key role in the maintenance of self-tolerance, thus preventing autoimmune disease, as well as inhibiting harmful inflammatory diseases such as asthma and inflammatory bowel disease. PMID:15251137

Thompson, Claire; Powrie, Fiona



Interleukin 7 receptor-deficient mice lack gammadelta T cells.  

PubMed Central

The interleukin 7 receptor (IL-7R) plays a crucial role in early B- and T-cell development. It consists of a unique a chain and a common gamma chain [IL-2 receptor gamma chain (IL-2Rgamma)]. Gene inactivation of IL-7, IL-7R, and IL-2Rgamma resulted in severe impairment of B and T lymphopoiesis in mice. In addition, IL-2Rgamma-deficient mice lack gammadelta T cells in the skin and have the impaired development of natural killer (NK) cells and intraepithelial lymphocytes. To explore the role of IL-7/IL-7R system in gammadelta T- and NK-cell development, we have generated and analyzed IL-7R-deficient mice. gammadelta T cells were absent from skin, gut, liver, and spleen in the deficient mice. In contrast, alphabeta T and B cells were detected in reduced, but certain, numbers, and NK cells developed normally. The gammadelta T-cell development in fetal and adult thymus was also completely blocked. These results clearly demonstrate that the signal from IL-7R is indispensable for gammadelta T-cell development in both thymic and extrathymic pathways. On the contrary, it is suggested that NK-cell development requires cytokine(s) other than IL-7. Images Fig. 1 Fig. 4

Maki, K; Sunaga, S; Komagata, Y; Kodaira, Y; Mabuchi, A; Karasuyama, H; Yokomuro, K; Miyazaki, J I; Ikuta, K



FoxP3 and Bcl-xL cooperatively promote regulatory T cell persistence and prevention of arthritis development  

PubMed Central

Introduction Forkhead box p3 (FoxP3)-expressing regulatory T cells (Tregs) have been clearly implicated in the control of autoimmune disease in murine models. In addition, ectopic expression of FoxP3 conveys a Treg phenotype to CD4+ T cells, lending itself to therapeutic use in the prevention of rheumatoid arthritis (RA). In this study, we generated therapeutically active Tregs with an increased life span and hence greater therapeutic potential. Methods We used retrovirus-mediated transduction to introduce FoxP3 or FoxP3 with anti-apoptotic Bcl-2 family molecule Bcl-xL linked by a 2A picornavirus self-cleaving peptide into CD4+ T cells to generate Tregs. In addition, by using in vitro functional analyses and adoptive immunotherapy in a murine model of RA, we demonstrated that these Tregs were highly reactive. Results We found that CD4+ T cells expressing both FoxP3 and Bcl-xL were able to differentiate into functional Tregs, which have a long-term survival advantage over cells transduced with FoxP3 alone. In an in vivo murine model, adoptive transfer of Tregs expressing both FoxP3 and Bcl-xL demonstrated more effective suppression of RA than CD4+ T cells expressing FoxP3 alone. Conclusions FoxP3 and Bcl-xL can cooperatively promote the differentiation and persistence of Tregs, with the capacity to prevent arthritis. Our results provide a novel approach for generating highly reactive Tregs for augmenting cellular immunotherapy for autoimmune disease.



Correlation between recent thymic emigrants and CD31+ (PECAM-1) CD4+ T cells in normal individuals during aging and in lymphopenic children.  


CD31(+)CD45RA(+)RO(-) lymphocytes contain high numbers of T cell receptor circle (TREC)-bearing T cells; however, the correlation between CD31(+)CD4(+) lymphocytes and TREC during aging and under lymphopenic conditions has not yet been sufficiently investigated. We analyzed TREC, telomere length and telomerase activity within sorted CD31(+) and CD31(-) CD4(+) lymphocytes in healthy individuals from birth to old age. Sorted CD31(+)CD45RA(+)RO(-) naive CD4(+) lymphocytes contained high TREC numbers, whereas CD31(+)CD45RA(-)RO(+) cells (comprising < or =5% of CD4(+) cells during aging) did not contain TREC. CD31(+) overall CD4(+) cells remained TREC rich despite an age-related tenfold reduction from neonatal (100 : 1000) to old age (10 : 1000). Besides a high TREC content, CD31(+)CD45RA(+)RO(-)CD4(+) cells exhibited significantly longer telomeres and higher telomerase activity than CD31(-)CD45RA(+)RO(-)CD4(+) cells, suggesting that CD31(+)CD45RA(+)RO(-)CD4(+) cells represent a distinct population of naive T cells with particularly low replicative history. To analyze the value of CD31 in lymphopenic conditions, we investigated six children after allogeneic hematopoietic stem cell transplantation (HSCT). Reemerging overall CD4(+) as well as naive CD45RA(+)RO(-)CD4(+) cells predominantly expressed CD31 and correlated well with the recurrence of TREC 5-12 months after HSCT. Irrespective of limitations in the elderly, CD31 is an appropriate marker to monitor TREC-rich lymphocytes essentially in lymphopenic children after HSCT. PMID:17935071

Junge, Sonja; Kloeckener-Gruissem, Barbara; Zufferey, Romain; Keisker, Andre; Salgo, Bettina; Fauchere, Jean-Claude; Scherer, Franziska; Shalaby, Tarek; Grotzer, Michael; Siler, Ulrich; Seger, Reinhard; Güngör, Tayfun



T cell-independent development and induction of somatic hypermutation in human IgM+IgD+CD27+ B cells  

PubMed Central

IgM+IgD+CD27+ B cells from peripheral blood have been described as circulating marginal zone B cells. It is still unknown when and where these cells develop. These IgM+IgD+CD27+ B cells exhibit somatic hypermutations (SHMs) in their B cell receptors, but the exact nature of the signals leading to induction of these SHMs remains elusive. Here, we show that IgM+IgD+CD27+ B cells carrying SHMs are observed during human fetal development. To examine the role of T cells in human IgM+IgD+CD27+ B cell development we used an in vivo model in which Rag2?/??C?/? mice were repopulated with human hematopoietic stem cells. Using Rag2?/??C?/? mice on a Nude background, we demonstrated that development and induction of SHMs of human IgM+IgD+CD27+ B cells can occur in a T cell–independent manner.

Scheeren, Ferenc A.; Nagasawa, Maho; Weijer, Kees; Cupedo, Tom; Kirberg, Jorg; Legrand, Nicolas; Spits, Hergen



Involvement of Ca/sup 2 +//phospholipid-dependent C-kinase in phorbol ester-mediated activation of normal human T cell  

SciTech Connect

C-kinase appears to be involved in biological responses of T cells, and phorbol myristate acetate (PMA) is a direct activator of this enzyme. In this study, reaction of T cells with PMA (0.1-50 ng/ml) showed a dose-dependent increase in /sup 3/H-thymidine incorporation; higher concentrations were toxic. C-kinase assays performed in parallel demonstrated sustained translocation of >99% of C-kinase activity from the cytosol to the detergent-soluble membrane fraction. Experiments were done in the presence of cyclosporine (CSA), and of polymyxin B (PMB) which also inhibits C-kinase. Both PMA and CSA caused profound and dose-dependent reduction in proliferation, with maximal inhibition of >70% and >90% respectively. Moreover, addition of PMB showed coordinate inhibition of C-kinase activity (>80% at 10, whereas at similar concentrations inhibiting cell proliferation CSA had no detectable effect. These results indicate that PMA initiates activation and proliferation by stimulation of at least two distinct pathways, one of which involves C-kinase activation and is inhibited by PMB.

Dirienzo, W.; Nel, A.E.; Lattanze, G.R.; Galbraith, R.M.



Antigen-specific regulatory T cells develop via the ICOS–ICOS-ligand pathway and inhibit allergen-induced airway hyperreactivity  

Microsoft Academic Search

Asthma is caused by T-helper cell 2 (Th2)-driven immune responses, but the immunological mechanisms that protect against asthma development are poorly understood. T-cell tolerance, induced by respiratory exposure to allergen, can inhibit the development of airway hyperreactivity (AHR), a cardinal feature of asthma, and we show here that regulatory T (TR) cells can mediate this protective effect. Mature pulmonary dendritic

Omid Akbari; Gordon J. Freeman; Everett H. Meyer; Edward A. Greenfield; Tammy T. Chang; Arlene H. Sharpe; Gerald Berry; Rosemarie H. DeKruyff; Dale T. Umetsu



IL17 production from activated T cells is required for the spontaneous development of destructive arthritis in mice deficient in IL1 receptor antagonist  

Microsoft Academic Search

IL-17 is a T cell-derived, proinflammatory cytokine that is suspected to be involved in the development of various inflammatory diseases. Although there are elevated levels of IL-17 in synovial fluid of patients with rheumatoid arthritis, the pathogenic role of IL-17 in the development of rheumatoid arthritis remains to be elucidated. In this report, the effects of IL-17 deficiency were examined

Susumu Nakae; Shinobu Saijo; Reiko Horai; Katsuko Sudo; Shigeo Mori; Yoichiro Iwakura



Engineering T cells for cancer therapy  

Microsoft Academic Search

It is generally accepted that the immune system plays an important role in controlling tumour development. However, the interplay between tumour and immune system is complex, as demonstrated by the fact that tumours can successfully establish and develop despite the presence of T cells in tumour. An improved understanding of how tumours evade T-cell surveillance, coupled with technical developments allowing

W Mansoor; D E Gilham; F C Thistlethwaite; R E Hawkins



Microbial parasites versus developing T cells: an evolutionary 'arms race' with implications for the timing of thymic involution and HIV pathogenesis.  


The thymus attempts to ensure that T cells which emerge from it are able to discriminate self from nonself. As such, it is a potential 'backdoor' through which microbial parasites can enter, manipulate the host into perceiving them as 'self', and thereby avoid immune surveillance. It is proposed that the host has evolved to overcome this parasitic strategy by rapidly producing large numbers of long-lived T cells very early in life (closing the backdoor), before the developing individual has significant contact with infectious organisms, and while still under the protection of its mother's intact immune system. Hence the capacity of the thymus to function efficiently early in the lifespan would have been strongly favored by natural selection. It is well established in evolutionary biology that strong selection favoring enhanced early function easily accommodates, through pleiotropy, the accumulation of later occurring negative effects, and it is through this process that thymic involution and subsequent immune system senescence may have evolved. Once a large pool of competent T cells has been produced, even those microbes capable of contaminating the thymus usually can be eliminated, or at least contained. However, microbes that both destroy peripheral T cells (particularly peripheral T cells that are activated against them), and contaminate the thymus (leading to deletion of potential replacements of the destroyed peripheral cells), may be able to eventually overcome the immune system, thus producing disease after a long period of apparent latency. Human immunodeficiency virus, which is initially well controlled by the immune system, may become unleashed via this process. PMID:8629277

Turke, P W


The Role of Brg1 , a Catalytic Subunit of Mammalian Chromatin-remodeling Complexes, in T Cell Development  

Microsoft Academic Search

Mammalian SWI-SNF-related complexes use brahma-related gene 1 ( Brg1 ) as a catalytic subunit to remodel nucleosomes and regulate transcription. Recent biochemical data has linked Brg1 function to genes important for T lymphocyte differentiation. To investigate the role of SWI- SNF-related complexes in this lineage, we ablated Brg1 function in T lymphocytes. T cell-specific Brg1 -deficient mice showed profound thymic

Thomas C. Gebuhr; Grigoriy I. Kovalev; Scott Bultman; Virginia Godfrey; Lishan Su; Terry Magnuson


CD40 ligand-transduced co-stimulation of T cells in the development of helper function  

Microsoft Academic Search

MICE that lack either CD401,2 (expressed on B cells) or CD40 ligand3,4 (expressed on activated T cells) are able neither to make IgG, IgA or IgE antibody responses, nor to generate germinal centres (the sites of formation of memory B cells). It has been assumed that these lesions were the result of an absence of signals to B cells through

Dominic Van Essen; Hitoshi Kikutani; David Gray



The development of T cell-dominated inflammatory responses induced by sodium lauryl sulphate in mouse oral mucosa.  


The effect of a single time exposure of SLS to the buccal mucosa of mice was compared to one application of the hapten OXA (oxazolone), evaluated by routine histology, immunohistochemistry and ELISA quantifications of cytokines. The SLS concentrations (2%, 4% and 8%) resulted in epithelial surface necrosis at 1-6 h, after 2-6 h accumulation of intra-epithelial neutrophils and at 24 h the main inflammatory cells were mononuclear. Increased concentrations of SLS gave more severe damage. CD4(+) T cells were found at 6 h and increased slightly up to 24 h and were most frequently seen at the lowest SLS dose. The CD8(+) T cells were kept at a low number during the whole 24 h observation period, but increased proportionally to the CD4(+) T cells. One application of 1% OXA did not raise the number of cells of either phenotype (2-24 h). Neither IL-2 nor IFN-? demonstrated increased levels during the week of observation at any concentration of SLS, contrary to one application of OXA which caused increased IL-2 levels both at the local application site and in the regional and distant lymph nodes. Regardless of SLS concentration, a minor increase in regional lymph node weight was observed 8-12 h after substance application, quickly to subside whilst one OXA application gave a maximal weight increase at 48-72 h. We conclude that oral mucosa irritant SLS reactions gave early surface necrosis and neutrophil infiltrations and later mononuclear cell infiltrations dominated by CD4(+) T cells. The cytokines IL-2 and IFN-? and lymphocyte proliferation in the regional lymph nodes was not observed after SLS application, contrary to hapten application. PMID:22153318

Ahlfors, E E; Dahl, J E; Lyberg, T



T-cell recognition of chemicals, protein allergens and drugs: towards the development of in vitro assays  

Microsoft Academic Search

Chemicals can elicit T-cell-mediated diseases such as allergic contact dermatitis and adverse drug reactions. Therefore, testing\\u000a of chemicals, drugs and protein allergens for hazard identification and risk assessment is essential in regulatory toxicology.\\u000a The seventh amendment of the EU Cosmetics Directive now prohibits the testing of cosmetic ingredients in mice, guinea pigs\\u000a and other animal species to assess their sensitizing

Stefan F. Martin; Philipp R. Esser; Sonja Schmucker; Lisa Dietz; Dean J. Naisbitt; B. Kevin Park; Marc Vocanson; Jean-Francois Nicolas; Monika Keller; Werner J. Pichler; Matthias Peiser; Andreas Luch; Reinhard Wanner; Enrico Maggi; Andrea Cavani; Thomas Rustemeyer; Anne Richter; Hermann-Josef Thierse; Federica Sallusto



HTLV-1 and Leukemogenesis: Virus-Cell Interactions in the Development of Adult T-Cell Leukemia.  


Human T-cell lymphotropic virus type 1 (HTLV-1) was originally discovered in the early 1980s. It is the first retrovirus to be unambiguously linked causally to a human cancer. HTLV-1 currently infects approximately 20 million people worldwide. In this chapter, we review progress made over the last 30 years in our understanding of HTLV-1 infection, replication, gene expression, and cellular transformation. PMID:24008300

Zane, Linda; Jeang, Kuan-Teh



Generation of functional human T cell hybrids  

PubMed Central

Human T cell hybrids were generated by fusing lectin-activated normal and leukemic human T cells with an aminopterin-sensitive human T cell line. This mutant cell line, designated CEM-T15, was derived from the human T cell line CEM after chemical mutagenesis with ethane methylsulfonate and subsequent culture in medium containing 6- thioguanine. After polyethylene glycol-induced fusion, the cells were cultured in hypoxanthine-aminopterin-thymidine selective medium. More than 5 wk after fusion, evidence for successful hybridization was obtained by three independent criteria: (a) The majority of the cultures contained cells expressing the OKT3 surface antigen: this antigen is expressed on normal T cells but not on CEM-T15 cells. (b) Most of the cultures contained polyploid cells. (c) Some of the cultures provided helper activity in the generation of antibody-forming cells. This functional activity is absent from the CEM-T15 parental cell line. Evidence for functional stability of the hybrids greater than 20 wk after fusion was provided by several clones that not only continue growing exponentially but also maintain expression of OKT3 surface antigen and high levels of helper function. These T cell hybrids constructed using antigen-specific human T cells should be of considerable importance in further studies of the immunobiology of human T cells.



T cells in myositis  

PubMed Central

T cells of both the CD4 and CD8 lineage are commonly found in affected tissues of patients with idiopathic inflammatory myopathies, but understanding the contribution of these cells to immunopathogenesis remains challenging. Given recent advances in identifying more myositis-associated autoantibodies and their putative targets, we suggest that studies on autoreactive T cells targeting those autoantigens are one way forward. Another (so far, more frequently used) approach comes from studies on effector T cells in the context of myositis. This review summarizes recent advances and current hypotheses in both of these contexts.



T Cell Activation  

PubMed Central

This year marks the twenty-fifth anniversary of the first Annual Review in Immunology article to describe features of the T cell antigen receptor (TCR). In celebration of this anniversary, we begin with a brief introduction outlining the chronology of the earliest studies that established the basic paradigm for how the engaged TCR transduces its signals. This review continues with a description of the current state of our understanding of TCR signaling, as well as a summary of recent findings examining other key aspects of T cell activation including crosstalk between the TCR and integrins, the role of costimulatory molecules, and how signals may negatively regulate T cell function.

Smith-Garvin, Jennifer E.; Koretzky, Gary A.; Jordan, Martha S.



T cells in atherosclerosis.  


Atherosclerosis is a chronic inflammatory disease of the artery wall. Atherosclerotic lesions contain monocytes, macrophages, smooth muscle cells and T lymphocytes. Here, we review the role of T-lymphocyte subsets in atherosclerosis. Among CD4(+) T cells, Th1 cells are pro-atherogenic, Treg cells are athero-protective and the role of Th2 and Th17 cells remains unclear. The role of follicular helper T cells in atherosclerosis remains unknown, as is the role of CD8(+) T cells. NKT cells bind glycolipid antigens and exert a pro-atherogenic role. The antigen specificity of T-cell responses in atherosclerosis is poorly understood. In order to enable antigen-specific prevention or therapy, a better understanding of these mechanisms is needed. PMID:24154816

Tse, Kevin; Tse, Harley; Sidney, John; Sette, Alex; Ley, Klaus



Inhibition of T Cell and Promotion of Natural Killer Cell Development by the Dominant Negative Helix Loop Helix Factor Id3  

PubMed Central

Bipotential T/natural killer (NK) progenitor cells are present in the human thymus. Despite their bipotential capacity, these progenitors develop predominantly to T cells in the thymus. The mechanisms controlling this developmental choice are unknown. Here we present evidence that a member(s) of the family of basic helix loop helix (bHLH) transcription factors determines lineage specification of NK/T cell progenitors. The natural dominant negative HLH factor Id3, which blocks transcriptional activity of a number of known bHLH factors, was expressed in CD34+ progenitor cells by retrovirus-mediated gene transfer. Constitutive expression of Id3 completely blocks development of CD34+ cells into T cells in a fetal thymic organ culture (FTOC). In contrast, development into NK cells in an FTOC is enhanced. Thus, the activity of a bHLH transcription factor is necessary for T lineage differentiation of bipotential precursors, in the absence of which a default pathway leading to NK cell development is chosen. Our results identify a molecular switch for lineage specification in early lymphoid precursors of humans.

Heemskerk, Mirjam H.M.; Blom, Bianca; Nolan, Garry; Stegmann, Alexander P.A.; Bakker, Arjen Q.; Weijer, Kees; Res, Pieter C.M.; Spits, Hergen



Protection by antioxidants against toxicity and apoptosis induced by the sulphur mustard analog 2-chloroethylethyl sulphide (CEES) in Jurkat T cells and normal human lymphocytes.  


1. The mechanism of toxicity of sulphur mustard was investigated by examining the biochemical effects of the analog 2-chloroethylethyl sulphide (CEES) in both human Jurkat cells as well as normal human lymphocytes. 2. Exposure of both types of cells to CEES resulted in a marked decrease in the intracellular concentration of the reduced form of glutathione (GSH), and CEES-induced cell death was potentiated by l-buthionine sulphoximine, an inhibitor of GSH synthesis. 3. CEES increased the endogenous production of reactive oxygen species (ROS) in Jurkat cells, and CEES-induced cell death was potentiated by hydrogen peroxide. 4. CEES induced various hallmarks of apoptosis, including collapse of the mitochondrial membrane potential, proteolytic processing and activation of procaspase-3, and cleavage of poly (ADP-ribose) polymerase. 5. The effects of CEES on the accumulation of ROS, the intracellular concentration of GSH, the mitochondrial membrane potential, and caspase-3 activity were all inhibited by pretreatment of cells with the GSH precursor N-acetyl cysteine or with GSH-ethyl ester. Furthermore, CEES-induced cell death was also prevented by these antioxidants. 6. CEES toxicity appears to be mediated, at least in part, by the generation of ROS and consequent depletion of GSH. Given that sulphur mustard is still a potential biohazard, the protective effects of antioxidants against CEES toxicity demonstrated in Jurkat cells and normal human lymphocytes may provide the basis for the development of a therapeutic strategy to counteract exposure to this chemical weapon. PMID:14769780

Han, Suhua; Espinoza, Luis A; Liao, Hongling; Boulares, A Hamid; Smulson, Mark E



Protection by antioxidants against toxicity and apoptosis induced by the sulphur mustard analog 2-chloroethylethyl sulphide (CEES) in Jurkat T cells and normal human lymphocytes  

PubMed Central

The mechanism of toxicity of sulphur mustard was investigated by examining the biochemical effects of the analog 2-chloroethylethyl sulphide (CEES) in both human Jurkat cells as well as normal human lymphocytes. Exposure of both types of cells to CEES resulted in a marked decrease in the intracellular concentration of the reduced form of glutathione (GSH), and CEES-induced cell death was potentiated by L-buthionine sulphoximine, an inhibitor of GSH synthesis. CEES increased the endogenous production of reactive oxygen species (ROS) in Jurkat cells, and CEES-induced cell death was potentiated by hydrogen peroxide. CEES induced various hallmarks of apoptosis, including collapse of the mitochondrial membrane potential, proteolytic processing and activation of procaspase-3, and cleavage of poly (ADP-ribose) polymerase. The effects of CEES on the accumulation of ROS, the intracellular concentration of GSH, the mitochondrial membrane potential, and caspase-3 activity were all inhibited by pretreatment of cells with the GSH precursor N-acetyl cysteine or with GSH-ethyl ester. Furthermore, CEES-induced cell death was also prevented by these antioxidants. CEES toxicity appears to be mediated, at least in part, by the generation of ROS and consequent depletion of GSH. Given that sulphur mustard is still a potential biohazard, the protective effects of antioxidants against CEES toxicity demonstrated in Jurkat cells and normal human lymphocytes may provide the basis for the development of a therapeutic strategy to counteract exposure to this chemical weapon.

Han, Suhua; Espinoza, Luis A; Liao, Hongling; Boulares, A Hamid; Smulson, Mark E



Development of multiple monoclonal serum immunoglobulins (multiclonal gammopathy) following both HLA-identical unfractionated and T cell-depleted haploidentical bone marrow transplantation in severe combined immunodeficiency  

Microsoft Academic Search

We have identified five patients with severe combined immunodeficiency (SCID) who developed multiple monoclonal serum immunoglobulin components (multiclonal gammopathy) following bone marrow transplantation. Four patients received haploidentical bone marrow stem cells depleted of T cells and other mature marrow cells by soy lectin agglutination and\\/or sheep erythrocyte rosetting. One patient received unfractionated HLA-identical bone marrow. Twenty-one distinct paraproteins were detected:

E. F. Kent; J. Crawford; H. J. Cohen; R. H. Buckley



Pushing the frontiers of T-cell vaccines: accurate measurement of human T-cell responses  

PubMed Central

There is a need for novel approaches to tackle major vaccine challenges such as malaria, tuberculosis and HIV, among others. Success will require vaccines able to induce a cytotoxic T-cell response – a deficiency of most current vaccine approaches. The successful development of T-cell vaccines faces many hurdles, not least being the lack of consensus on a standardized T-cell assay format able to be used as a correlate of vaccine efficacy. Hence, there remains a need for reproducible measures of T-cell immunity proven in human clinical trials to correlate with vaccine protection. The T-cell equivalent of a neutralizing antibody assay would greatly accelerate the development and commercialization of T-cell vaccines. Recent advances have seen a plethora of new T-cell assays become available, including some like cytometry by time-of-flight with extreme multiparameter T-cell phenotyping capability. However, whether it is historic thymidine-based proliferation assays or sophisticated new cytometry assays, each assay has its relative advantages and disadvantages, and relatively few of these assays have yet to be validated in large-scale human vaccine trials. This review examines the current range of T-cell assays and assesses their suitability for use in human vaccine trials. Should one or more of these assays be accepted as an agreed surrogate of T-cell protection by a regulatory agency, this would significantly accelerate the development of T-cell vaccines.

Saade, Fadi; Gorski, Stacey Ann; Petrovsky, Nikolai



Constitutive activation of Wnt signaling favors generation of memory CD8 T cells1  

PubMed Central

TCF-1 and LEF-1, the effector transcription factors of the canonical Wnt pathway, are known to be critical for normal thymocyte development. However, it is largely unknown if it has a role in regulating mature T cell activation and T cell-mediated immune responses. Here we demonstrate that like IL-7R? and CD62L, TCF-1 and LEF-1 exhibit dynamic expression changes during T cell responses, being highly expressed in naïve T cells, downregulated in effector T cells, and upregulated again in memory T cells. Enforced expression of a p45 TCF-1 isoform limited the expansion of antigen-specific CD8 T cells in response to Listeria monocytogenes infection. However, when the p45 transgene was coupled with ectopic expression of stabilized ?-catenin, more antigen-specific memory CD8 T cells were generated, with enhanced ability to produce IL-2. Moreover, these memory CD8 T cells expanded to a larger number of secondary effectors and cleared bacteria faster when the immunized mice were rechallenged with virulent L. monocytogenes. Furthermore, in response to vaccinia virus or lymphocytic choriomeningitis virus infection, more antigen-specific memory CD8 T cells were generated in the presence of p45 and stabilized ?-catenin transgenes. Although activated Wnt signaling also resulted in larger numbers of antigen-specific memory CD4 T cells, their functional attributes and expansion after the secondary infection were not improved. Thus, constitutive activation of the canonical Wnt pathway favors memory CD8 T cell formation during initial immunization, resulting in enhanced immunity upon second encounter with the same pathogen.

Zhao, Dong-Mei; Yu, Shuyang; Zhou, Xinyuan; Haring, Jodie S.; Held, Werner; Badovinac, Vladimir P.; Harty, John T.; Xue, Hai-Hui



CD8+ Effector T Cells at the Fetal-Maternal Interface, Balancing Fetal Tolerance and Antiviral Immunity  

PubMed Central

During pregnancy CD8+ effector T cells need optimal immune regulation to prevent a detrimental response to allogeneic fetal cells while providing immune protection to infections. A significant proportion of (prospective) mothers carry naïve or memory CD8+ T cells with a TCR that can directly bind to paternal MHC molecules. In addition, a high percentage of pregnant women develop specific T cell responses to fetal minor histocompatibility antigens (mHags). Under normal conditions, fetal–maternal MHC and mHag mismatches lead to elevated lymphocyte activation but do not induce pregnancy failure. Furthermore, viral infections alter the maternal CD8+ T cell response by changing the CD8+ T cell repertoire and increasing the influx of CD8+ T cells to decidual tissue. The normally high T cell activation threshold at the fetal–maternal interface may prevent efficient clearance of viral infections. Conversely, the increased inflammatory response due to viral infections may break fetal–maternal tolerance and lead to pregnancy complications. The aim of this review is to discuss the recent studies of CD8+ T cells in pregnancy, identify potential mechanisms for antigen-specific immune recognition of fetal extravillous trophoblast (EVT) cells by CD8+ T cells, and discuss the impact of viral infections and virus-specific CD8+ T cells during pregnancy.

Tilburgs, Tamara; Strominger, Jack L.



Derivation and maintenance of virtual memory CD8 T cells  

PubMed Central

Memory CD8+ T cells are an important component of the adaptive immune response against many infections, and understanding how antigen-specific memory CD8+ T cells are generated and maintained is crucial for the development of vaccines. We recently reported the existence of memory-phenotype, antigen-specific CD8+ T cells in unimmunized mice (“virtual memory” or VM cells). However, it was not clear when and where these cells are generated during normal development, nor the factors required for their production and maintenance. This issue is especially pertinent given recent data showing that memory-like CD8 T cells can be generated in the thymus, in a “bystander” response to IL-4. Here we show that the size of the VM population is reduced in IL-4R-deficient animals. However, the VM population appears first in the periphery and not the thymus of normal animals, suggesting this role of IL-4 is manifest following thymic egress. We also show that the VM pool is durable, showing basal proliferation and long term maintenance in normal animals, and also being retained during responses to unrelated infection.

Akue, Adovi D.; Lee, June-Yong; Jameson, Stephen C.



Fas-Mediated Apoptosis Regulates the Composition of Peripheral ?? T Cell Repertoire by Constitutively Purging Out Double Negative T Cells  

PubMed Central

Background The Fas pathway is a major regulator of T cell homeostasis, however, the T cell population that is controlled by the Fas pathway in vivo is poorly defined. Although CD4 and CD8 single positive (SP) T cells are the two major T cell subsets in the periphery of wild type mice, the repertoire of mice bearing loss-of-function mutation in either Fas (lpr mice) or Fas ligand (gld mice) is predominated by CD4?CD8? double negative ?? T cells that also express B220 and generally referred to as B220+DN T cells. Despite extensive analysis, the basis of B220+DN T cell lymphoproliferation remains poorly understood. In this study we re-examined the issue of why T cell lymphoproliferation caused by gld mutation is predominated by B220+DN T cells. Methodology and Principal Findings We combined the following approaches to study this question: Gene transcript profiling, BrdU labeling, and apoptosis assays. Our results show that B220+DN T cells are proliferating and dying at exceptionally high rates than SP T cells in the steady state. The high proliferation rate is restricted to B220+DN T cells found in the gut epithelium whereas the high apoptosis rate occurred both in the gut epithelium and periphery. However, only in the periphery, apoptosis of B220+DN T cell is Fas-dependent. When the Fas pathway is genetically impaired, apoptosis of peripheral B220+DN T cells was reduced to a baseline level similar to that of SP T cells. Under these conditions of normalized apoptosis, B220+DN T cells progressively accumulate in the periphery, eventually resulting in B220+DN T cell lymphoproliferation. Conclusions/Significance The Fas pathway plays a critical role in regulating the tissue distribution of DN T cells through targeting and elimination of DN T cells from the periphery in the steady state. The results provide new insight into pathogenesis of DN T cell lymphoproliferation.

Mohamood, Abdiaziz S.; Bargatze, Dylan; Xiao, Zuoxiang; Jie, Chunfa; Yagita, Hideo; Ruben, Dawn; Watson, Julie; Chakravarti, Shukti; Schneck, Jonathan P.; Hamad, Abdel Rahim A.



Role of Neuronal Interferon-? in the Development of Myelopathy in Rats Infected with Human T-Cell Leukemia Virus Type 1  

PubMed Central

Human T-cell leukemia virus type 1 (HTLV-1) is the causative agent of not only adult T-cell leukemia but also HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP). Among the rat strains infected with HTLV-1, chronic progressive myelopathy, named HAM rat disease, occurs exclusively in WKAH rats. In the present study, we found that HTLV-1 infection induces interferon (IFN)-? production in the spinal cords of HAM-resistant strains but not in those of WKAH rats. Neurons were the major cells that produced IFN-? in HTLV-1-infected, HAM-resistant strains. Administration of IFN-? suppressed expression of pX, the gene critically involved in the onset of HAM rat disease, in an HTLV-1-immortalized rat T-cell line, indicating that IFN-? protects against the development of HAM rat disease. The inability of WKAH spinal cord neurons to produce IFN-? after infection appeared to stem from defects in signaling through the interleukin (IL)-12 receptor. Specifically, WKAH-derived spinal cord cells were unable to up-regulate the IL-12 receptor ?2 gene in response to IL-12 stimulation. We suggest that the failure of spinal cord neurons to produce IFN-? through the IL-12 pathway is involved in the development of HAM rat disease.

Miyatake, Yukiko; Ikeda, Hitoshi; Ishizu, Akihiro; Baba, Tomohisa; Ichihashi, Toru; Suzuki, Akira; Tomaru, Utano; Kasahara, Masanori; Yoshiki, Takashi



SM934 Treated Lupus-Prone NZBxNZW F1 Mice by Enhancing Macrophage Interleukin-10 Production and Suppressing Pathogenic T Cell Development  

PubMed Central

Background Artemisinin and its derivatives were reported to possess strong regulatory effects on inflammation and autoimmune diseases. This study was designed to examine the therapeutic effects and underlying mechanisms of SM934, a water-soluble artemisinin analogue, on lupus-prone female NZB×NZW F1 mice. Methodology/Principal Findings NZB/W F1 mice were treated orally with SM934 for 3 or 6 months respectively to investigate the effect on clinical manifestations and immunological correlates. To further explore the mechanisms of SM934, ovalbumin (OVA)-immunized or interferon (IFN)-?-elicited C57BL/6 mice were used. In vivo, treatment with SM934 for 3 or 6 months significantly delayed the progression of glomerulonephritis and increased the survival rate of NZB/W F1 mice. Clinical improvement was accompanied with decreased Th1-related anti-double-strand DNA (dsDNA) IgG2a and IgG3 Abs, serum interleukin (IL)-17, and increased Th2-related anti-dsDNA IgG1 Ab, serum IL-10 and IL-4. SM934 treatment also suppressed the accumulation of effector/memory T cells, induced the apoptosis of CD4+ T cells, while enhancing the development of regulatory T cells in NZB/W F1 mice. In addition, SM934 treatment promoted the IL-10 production of macrophages from NZB/W F1 mice, OVA-immunized C57BL/6 mice and IFN-?-elicited C57BL/6 mice. In vitro, SM934 enhanced IL-10 production from primary macrophages stimulated with IFN-?. Conclusions/Significance The results of this study demonstrated that artemisinin analogue SM934 had therapeutic effects on lupus-prone female NZB/W F1 mice by inhibiting the pathogenic helper T cell development and enhancing anti-inflammatory cytokine IL-10 production.

Li, Xin; Wan, Chun-Ping; Yang, Yang; Zhang, Xiao-Hui; He, Pei-Lan; Zhou, Yu; Zhu, Feng-Hua; Yang, Yi-Fu; Li, Ying; Tang, Wei; Zuo, Jian-Ping



Transiently Reduced PI3K/Akt Activity Drives the Development of Regulatory Function in Antigen-Stimulated Na?ve T-Cells  

PubMed Central

Regulatory T-cells (Tregs) are central for immune homeostasis and divided in thymus-derived natural Tregs and peripherally induced iTreg. However, while phenotype and function of iTregs are well known, a remarkable lack exists in knowledge about signaling mechanisms leading to their generation from naïve precursors in peripheral tissues. Using antigen specific naïve T-cells from mice, we investigated CD4+ CD25+ FoxP3- iTreg induction during antigen-specific T-cell receptor (TCR) stimulation with weak antigen presenting cells (APC). We show that early signaling pathways such as ADAM-17-activation appeared similar in developing iTreg and effector cells (Teff) and both initially shedded CD62-L. But iTreg started reexpressing CD62-L after 24 h while Teff permanently downmodulated it. Furthermore, between 24 and 72 hours iTreg presented with significantly lower phosphorylation levels of Akt-S473 suggesting lower activity of the PI3K/Akt-axis. This was associated with a higher expression of the Akt hydrophobic motif-specific phosphatase PHLPP1 in iTreg. Importantly, the lack of costimulatory signals via CD28 from weak APC was central for the development of regulatory function in iTreg but not for the reappearance of CD62-L. Thus, T-cells display a window of sensitivity after onset of TCR triggering within which the intensity of the PI3K/Akt signal controls entry into either effector or regulatory pathways.

Hasenberg, Mike; Reichardt, Peter; Gunzer, Matthias



Normal Development of Brain Circuits  

Microsoft Academic Search

Spanning functions from the simplest reflex arc to complex cognitive processes, neural circuits have diverse functional roles. In the cerebral cortex, functional domains such as visual processing, attention, memory, and cognitive control rely on the development of distinct yet interconnected sets of anatomically distributed cortical and subcortical regions. The developmental organization of these circuits is a remarkably complex process that

Gregory Z Tau; Bradley S Peterson



Development of replication-defective lymphocytic choriomeningitis virus vectors for the induction of potent CD8+ T cell immunity  

PubMed Central

Lymphocytic choriomeningitis virus (LCMV) exhibits natural tropism for dendritic cells and represents the prototypic infection that elicits protective CD8+ T cell (cytotoxic T lymphocyte (CTL)) immunity. Here we have harnessed the immunobiology of this arenavirus for vaccine delivery. By using producer cells constitutively synthesizing the viral glycoprotein (GP), it was possible to replace the gene encoding LCMV GP with vaccine antigens to create replication-defective vaccine vectors. These rLCMV vaccines elicited CTL responses that were equivalent to or greater than those elicited by recombinant adenovirus 5 or recombinant vaccinia virus in their magnitude and cytokine profiles, and they exhibited more effective protection in several models. In contrast to recombinant adenovirus 5, rLCMV failed to elicit vector-specific antibody immunity, which facilitated re-administration of the same vector for booster vaccination. In addition, rLCMV elicited T helper type 1 CD4+ T cell responses and protective neutralizing antibodies to vaccine antigens. These features, together with low seroprevalence in humans, suggest that rLCMV may show utility as a vaccine platform against infectious diseases and cancer.

Flatz, Lukas; Hegazy, Ahmed N; Bergthaler, Andreas; Verschoor, Admar; Claus, Christina; Fernandez, Marylise; Gattinoni, Luca; Johnson, Susan; Kreppel, Florian; Kochanek, Stefan; van den Broek, Maries; Radbruch, Andreas; Levy, Frederic; Lambert, Paul-Henri; Siegrist, Claire-Anne; Restifo, Nicholas P; Lohning, Max; Ochsenbein, Adrian F; Nabel, Gary J; Pinschewer, Daniel D



Memory T cells and vaccines.  


T lymphocytes play a central role in the generation of a protective immune response in many microbial infections. After immunization, dendritic cells take up microbial antigens and traffic to draining lymph nodes where they present processed antigens to naïve T cells. These naïve T cells are stimulated to proliferate and differentiate into effector and memory T cells. Activated, effector and memory T cells provide B cell help in the lymph nodes and traffic to sites of infection where they secrete anti-microbial cytokines and kill infected cells. At least two types of memory cells have been defined in humans based on their functional and migratory properties. T central-memory (T(CM)) cells are found predominantly in lymphoid organs and can not be immediately activated, whereas T effector-memory (T(EM)) cells are found predominantly in peripheral tissue and sites of inflammation and exhibit rapid effector function. Most currently licensed vaccines induce antibody responses capable of mediating long-term protection against lytic viruses such as influenza and small pox. In contrast, vaccines against chronic pathogens that require cell-mediated immune responses to control, such as malaria, Mycobacterium tuberculosis (TB), human immunodeficiency virus (HIV) and hepatitis C virus (HCV), are currently not available or are ineffective. Understanding the mechanisms by which long-lived cellular immune responses are generated following vaccination should facilitate the development of safe and effective vaccines against these emerging diseases. Here, we review the current literature with respect to memory T cells and their implications to vaccine development. PMID:12531640

Esser, Mark T; Marchese, Rocio D; Kierstead, Lisa S; Tussey, Lynda G; Wang, Fubao; Chirmule, Narendra; Washabaugh, Michael W



Normal Development of Brain Circuits  

PubMed Central

Spanning functions from the simplest reflex arc to complex cognitive processes, neural circuits have diverse functional roles. In the cerebral cortex, functional domains such as visual processing, attention, memory, and cognitive control rely on the development of distinct yet interconnected sets of anatomically distributed cortical and subcortical regions. The developmental organization of these circuits is a remarkably complex process that is influenced by genetic predispositions, environmental events, and neuroplastic responses to experiential demand that modulates connectivity and communication among neurons, within individual brain regions and circuits, and across neural pathways. Recent advances in neuroimaging and computational neurobiology, together with traditional investigational approaches such as histological studies and cellular and molecular biology, have been invaluable in improving our understanding of these developmental processes in humans in both health and illness. To contextualize the developmental origins of a wide array of neuropsychiatric illnesses, this review describes the development and maturation of neural circuits from the first synapse through critical periods of vulnerability and opportunity to the emergent capacity for cognitive and behavioral regulation, and finally the dynamic interplay across levels of circuit organization and developmental epochs.

Tau, Gregory Z; Peterson, Bradley S



Progesterone suppresses Th17 cell responses, and enhances the development of regulatory T cells, through thymic stromal lymphopoietin-dependent mechanisms in experimental gonococcal genital tract infection.  


In most female patients, the symptoms of genital infection due to Neisseria gonorrhoeae tend to be slight or even absent. Our previous studies suggested that progesterone might play a role in female asymptomatic gonococcal infection. In this study, we demonstrated that progesterone induced the expression of thymic stromal lymphopoietin (TSLP) and regulatory T cells (Treg)-related transcription factor Foxp3, and inhibited the expression of Th17 related transcription factor ROR?t, and reduced the influx of neutrophils in murine vaginal gonococcal infection. Blockade of TSLP with antibody partially reversed the effects of progesterone on the murine model of gonococcal vaginal infection. In in vitro experiments, progesterone induced a rapid up-regulation of TSLP in vaginal epithelial cells stimulated with N. gonorrhoeae. Blocking thymic stromal lymphopoietin receptor (TSLPR) with a TSLPR monoclonal antibody partially prevented progesterone suppression of IL-17-producing T cells differentiation, and progesterone promotion of CD4(+)CD25(+)Foxp3(+) regulatory T cells differentiation. Altogether, our results indicate that the progesterone suppresses Th17 cell responses, and enhances the development of Treg cells, through TSLP-dependent mechanisms, and play a role in female asymptomatic gonococcal infections. PMID:23835188

Xu, Li; Dong, Bilin; Wang, Hui; Zeng, Zhiliang; Liu, Weihuang; Chen, Na; Chen, Jinbo; Yang, Jing; Li, Dongsheng; Duan, Yiqun



How Numbers, Nature, and Immune Status of Foxp3+ Regulatory T-Cells Shape the Early Immunological Events in Tumor Development  

PubMed Central

The influence of CD4+CD25+Foxp3+ regulatory T-cells (Tregs) on cancer progression has been demonstrated in a large number of preclinical models and confirmed in several types of malignancies. Neoplastic processes trigger an increase of Treg numbers in draining lymph nodes, spleen, blood, and tumors, leading to the suppression of anti-tumor responses. Treg-depletion before or early in tumor development may lead to complete tumor eradication and extends survival of mice and humans. However this strategy is ineffective in established tumors, highlighting the critical role of the early Treg-tumor encounters. In this review, after discussing old and new concepts of immunological tumor tolerance, we focus on the nature (thymus-derived vs. peripherally derived) and status (naïve or activated/memory) of the regulatory T-cells at tumor emergence. The recent discoveries in this field suggest that the activation status of Tregs and effector T-cells (Teffs) at the first encounter with the tumor are essential to shape the fate and speed of the immune response across a variety of tumor models. The relative timing of activation/recruitment of anti-tumor cells vs. tolerogenic cells at tumor emergence appears to be crucial in the identification of tumor cells as friend or foe, which has broad implications for the design of cancer immunotherapies.

Darrasse-Jeze, Guillaume; Podsypanina, Katrina



CD4+ T Cell-Depleted Lymphocyte Infusion Impairs Neither the Recovery of Recipient Thymus nor the Development of Transplanted Thymus  

PubMed Central

Thymus transplantation, in conjunction with bone marrow transplantation (BMT), has been attracting attention for the treatment of various diseases. Recently, donor lymphocyte infusion (DLI) has been used as a helpful tool for establishing donor chimerism and preventing a relapse of leukemia/lymphoma. However, the effects of DLI on transplanted and recipient thymuses have not been explored. We therefore performed DLI in the intrabone marrow–BMT + thymus transplantation setting. We have found that DLI leads to derangements in both recipient thymuses and transplanted thymuses; by 2 wk after BMT, we saw a decrease in total cell number, a lower percentage of CD4+CD8+ cells, and the obliteration of the thymic corticomedullary junction. Four weeks later, the thymic impairment became more serious. However, when we depleted the CD4+ T cells (CD4?-DLI), the recipient thymic recovery and transplanted thymic development were significantly restored by the treatment. In addition, there were much greater levels of TNF-? and Fas ligand, and a lower percentage of regulatory T cells in the DLI group than in the CD4?-DLI group. These findings indicate that inflammation induced by DLI, especially by CD4+ T cells, plays a crucial role in the thymic impairment.

Shi, Ming; Li, Ming; Cui, Yunze; Liu, Lin; Adachi, Yasushi



T Cell Receptor-initiated Calcium Release Is Uncoupled from Capacitative Calcium Entry in Itk-deficient T Cells  

Microsoft Academic Search

Summary Itk, a Tec family tyrosine kinase, plays an important but as yet undefined role in T cell receptor (TCR) signaling. Here we show that T cells from Itk-deficient mice have a TCR-proximal signaling defect, resulting in defective interleukin 2 secretion. Upon TCR stimulation, Itk 2 \\/ 2 T cells release normal amounts of calcium from intracellular stores, but fail

Karen-Qianye Liu; Stephen C. Bunnell; Christine B. Gurniak; Leslie J. Berg



Novel targeted therapies in peripheral T cell lymphoma.  


Peripheral T cell lymphomas (PTCL), non-Hodgkin lymphomas characterized by having features of T cells that have matured in the thymus, are a heterogeneous group of clinical entities. Compared with B cell lymphomas, they are less common, more difficult to diagnose and classify, more aggressive, and have inferior outcomes with current treatment paradigms. They are also less completely understood in terms of how different PTCL types correspond to normal T cell development, and in identifying cell signaling pathways as targets for new therapies. Recent studies with novel targeted therapies as single agents or in combination with other drugs have illustrated promising outcomes both for relapsed and frontline PTCL. We first briefly review classification, prognostic indices, and results of initial therapy of various T cell lymphomas. We then review recent studies of chemotherapy, monoclonal antibody-based therapy directed at cell surface targets, small molecule inhibitors of intracellular targets such as histone deacetylases and the proteasome, and agents that disrupt stromal interactions. Investigations that enhance our knowledge of T cell molecular biology and integrate novel targeted agents into the treatment algorithm for PTCL will be keys to improved outcomes for patients with PTCL. PMID:23819951

Jagadeesh, Deepa; Smith, Mitchell R



CD8 + T cells in systemic sclerosis  

Microsoft Academic Search

Systemic sclerosis (SSc) is a progressive and highly debilitating autoimmune disorder characterized by inflammation, fibrosis,\\u000a and vascular damage of the connective tissue. T cell-derived cytokines have been implicated in the induction of fibrosis. We found that high levels of the profibrotic type-2 cytokine IL-13 are produced by peripheral blood effector CD8+ T cells from SSc patients compared to normal controls.

Patrizia Fuschiotti



Spleen Tyrosine Kinase (Syk) Regulates Systemic Lupus Erythematosus (SLE) T Cell Signaling  

PubMed Central

Engagement of the CD3/T cell receptor complex in systemic lupus erythematosus (SLE) T cells involves Syk rather than the zeta-associated protein. Because Syk is being considered as a therapeutic target we asked whether Syk is central to the multiple aberrantly modulated molecules in SLE T cells. Using a gene expression array, we demonstrate that forced expression of Syk in normal T cells reproduces most of the aberrantly expressed molecules whereas silencing of Syk in SLE T cells normalizes the expression of most abnormally expressed molecules. Protein along with gene expression modulation for select molecules was confirmed. Specifically, levels of cytokine IL-21, cell surface receptor CD44, and intracellular molecules PP2A and OAS2 increased following Syk overexpression in normal T cells and decreased after Syk silencing in SLE T cells. Our results demonstrate that levels of Syk affect the expression of a number of enzymes, cytokines and receptors that play a key role in the development of disease pathogenesis in SLE and provide support for therapeutic targeting in SLE patients.

Grammatikos, Alexandros P.; Ghosh, Debjani; Devlin, Amy; Kyttaris, Vasileios C.; Tsokos, George C.



Molecular Characteristics of CTA056, a Novel Interleukin-2-Inducible T-Cell Kinase Inhibitor that Selectively Targets Malignant T Cells and Modulates Oncomirs  

PubMed Central

Interleukin-2-inducible T-cell kinase (Itk) is a member of the Btk (Bruton's tyrosine kinase) family of tyrosine kinases. Itk plays an important role in normal T-cell functions and in the pathophysiology of both autoimmune diseases and T-cell malignancies. Here, we describe the initial characterization of a selective inhibitor, 7-benzyl-1-(3-(piperidin-1-yl)propyl)-2-(4-(pyridin-4-yl)phenyl)-1H-imidazo[4,5-g]quinoxalin-6(5H)-one (CTA056), that was developed through screening a 9600-compound combinatorial solution phase library, followed by molecular modeling, and extensive structure-activity relationship studies. CTA056 exhibits the highest inhibitory effects toward Itk, followed by Btk and endothelial and epithelial tyrosine kinase. Among the 41 cancer cell lines analyzed, CTA056 selectively targets acute lymphoblastic T-cell leukemia and cutaneous T-cell lymphoma. Normal T cells are minimally affected. Incubation of Jurkat and MOLT-4 cells with CTA056 resulted in the inhibition of the phosphorylation of Itk and its effectors including PLC-?, Akt, and extracellular signal-regulated kinase, as well as the decreased secretion of targeted genes such as interleukin-2 and interferon-?. Jurkat cells also underwent apoptosis in a dose-dependent manner when incubated with CTA056. The potent apoptosis-inducing potential of CTA056 is reflected by the significant modulation of microRNAs involved in survival pathways and oncogenesis. The in vitro cytotoxic effect on malignant T cells is further validated in a xenograft model. The selective expression and activation of Itk in malignant T cells, as well as the specificity of CTA056 for Itk, make this molecule a potential therapeutic agent for the treatment of T-cell leukemia and lymphoma.

Guo, Wenchang; Liu, Ruiwu; Ono, Yoko; Ma, Ai-Hong; Martinez, Anthony; Sanchez, Eduardo; Wang, Yan; Huang, Wenzhe; Mazloom, Anisha; Li, Jixian; Ning, Jinying; Maverakis, Emanual; Lam, Kit S.



New insights into the role of VIP on the ratio of T-cell subsets during the development of autoimmune diabetes  

Microsoft Academic Search

Type I diabetes is an autoimmune T-cell-mediated disease associated with overexpression of inflammatory mediators and the disturbance of different T-cell subsets. Vasoactive intestinal peptide (VIP) is a potent anti-inflammatory agent with regulatory effects on activated T cells. As the equilibrium between different T-cell subsets is involved in the final outcome, leading to tolerance or autoimmunity, we studied the evolution of

Rebeca Jimeno; Rosa P Gomariz; Irene Gutiérrez-Cañas; Carmen Martínez; Yasmina Juarranz; Javier Leceta



CD4 T cells play important roles in maintaining IL-17-producing ?? T cell subsets in na?ve animals  

PubMed Central

A proportional balance between ?? and ?? T cell subsets in the periphery is exceedingly well maintained via a homeostatic mechanism. However, a cellular mechanism underlying the regulation remains undefined. We recently reported that a subset of developing ?? T cells spontaneously acquire IL-17-producing capacity even within naïve animals via a TGF?1-dependent mechanism, thus considered ‘einnate’ IL-17-producing cells. Here we report that ?? T cells generated within ?? T cell (or CD4 T cell)-deficient environments displayed altered cytokine profiles; particularly, ‘einnate’ IL-17 expression was significantly impaired compared to those in wild type mice. Impaired IL-17 production in ?? T cells was directly related to the CD4 T cell deficiency, because depletion of CD4 T cells in wild type mice diminished and adoptive CD4 T cell transfer into TCR??/? mice restored IL-17 expression in ?? T cells. CD4 T cell-mediated IL-17 expression required TGF?1. Moreover, Th17 but not Th1 or Th2 effector CD4 T cells were highly efficient in enhancing ?? T cell IL-17 expression. Taken together, our results highlight a novel CD4 T cell-dependent mechanism that shapes the generation of IL-17+ ?? T cells in naïve settings.

Do, Jeong-Su; Visperas, Anabelle; O'Brien, Rebecca L.; Min, Booki



Development of a System To Study CD4+-T-Cell Responses to Transgenic Ovalbumin-Expressing Toxoplasma gondii during Toxoplasmosis  

Microsoft Academic Search

The study of the immune response to Toxoplasma gondii has provided numerous insights into the role of T cells in resistance to intracellular infections. However, the complexity of this eukaryote pathogen has made it difficult to characterize immunodominant epitopes that would allow the identification of T cells with a known specificity for parasite antigens. As a consequence, analysis of T-cell

Marion Pepper; Florence Dzierszinski; Amy Crawford; Christopher A. Hunter; David Roos



Pivotal Role of Dermal IL-17-producing ?? T Cells in Skin Inflammation  

PubMed Central

Summary Interleukin (IL)-23 and CD4+ T helper-17 (Th17) cells are thought to be critical in the development of psoriasis. Here, we report that IL-23 predominantly stimulated dermal ??T cells to produce IL-17 that led to disease progression. Dermal ??T cells constitutively expressed the IL-23 receptor (IL-23R), ROR?t, and various chemokine receptors. IL-17 production from dermal ??T cells was independent of ??T cells. The epidermal hyperplasia and inflammation induced by IL-23 were significantly decreased in T cell receptor ? deficient (Tcrd?/?) and IL-17 receptor deficient (Il17ra?/?) mice but occurred normally in Tcra?/? mice. Imiquimod-induced skin pathology was also significantly decreased in Tcrd?/? mice. Perhaps further promoting disease progression, IL-23 stimulated dermal ??T cell expansion. In psoriasis patients, ??T cells were also greatly increased in affected skin and produced large amounts of IL-17. Thus, IL-23-responsive dermal ?? T cells are the major IL-17 producers in the skin and may represent a novel target for the treatment of psoriasis.

Cai, Yihua; Shen, Xiaoyan; Ding, Chuanlin; Qi, Chunjian; Li, Kejia; Li, Xia; Jala, Venkatakrishna R.; Zhang, Huang-ge; Wang, Tian; Zheng, Jie; Yan, Jun



CD8+ Memory T Cells Appear Exhausted within Hours of Acute Virus Infection.  


CD8(+) memory T cells are abundant and are activated in a near-synchronous manner by infection, thereby providing a unique opportunity to evaluate the coordinate functional and phenotypic changes that occur in vivo within hours of viral challenge. Using two disparate virus challenges of mice, we show that splenic CD8(+) memory T cells rapidly produced IFN-? in vivo; however, within 18-24 h, IFN-? synthesis was terminated and remained undetectable for ?48 h. A similar on/off response was observed in CD8(+) memory T cells in the peritoneal cavity. Cessation of IFN-? production in vivo occurred despite the continued presence of immunostimulatory viral Ag, indicating that the initial IFN-? response had been actively downregulated and that the cells had been rendered refractory to subsequent in vivo Ag contact. Downregulation of IFN-? synthesis was accompanied by the upregulation of inhibitory receptor expression on the T cells, and ex vivo analyses using synthetic peptides revealed a concurrent hierarchical loss of cytokine responsiveness (IL-2, then TNF, then IFN-?) taking place during the first 24 h following Ag contact. Thus, within hours of virus challenge, CD8(+) memory T cells display the standard hallmarks of T cell exhaustion, a phenotype that previously was associated only with chronic diseases and that is generally viewed as a gradually developing and pathological change in T cell function. Our data suggest that, instead, the "exhaustion" phenotype is a rapid and normal physiological T cell response. PMID:24026080

Hosking, Martin P; Flynn, Claudia T; Botten, Jason; Whitton, J Lindsay



WASH Knockout T Cells Demonstrate Defective Receptor Trafficking, Proliferation, and Effector Function  

PubMed Central

WASH is an Arp2/3 activator of the Wiskott-Aldrich syndrome protein superfamily that functions during endosomal trafficking processes in collaboration with the retromer and sorting nexins, but its in vivo function has not been examined. To elucidate the physiological role of WASH in T cells, we generated a WASH conditional knockout (WASHout) mouse model. Using CD4Cre deletion, we found that thymocyte development and naive T cell activation are unaltered in the absence of WASH. Surprisingly, despite normal T cell receptor (TCR) signaling and interleukin-2 production, WASHout T cells demonstrate significantly reduced proliferative potential and fail to effectively induce experimental autoimmune encephalomyelitis. Interestingly, after activation, WASHout T cells fail to maintain surface levels of TCR, CD28, and LFA-1. Moreover, the levels of the glucose transporter, GLUT1, are also reduced compared to wild-type T cells. We further demonstrate that the loss of surface expression of these receptors in WASHout cells results from aberrant accumulation within the collapsed endosomal compartment, ultimately leading to degradation within the lysosome. Subsequently, activated WASHout T cells experience reduced glucose uptake and metabolic output. Thus, we found that WASH is a newly recognized regulator of TCR, CD28, LFA-1, and GLUT1 endosome-to-membrane recycling. Aberrant trafficking of these key T cell proteins may potentially lead to attenuated proliferation and effector function.

Piotrowski, Joshua T.; Gomez, Timothy S.; Schoon, Renee A.; Mangalam, Ashutosh K.



Cutting Edge: Memory CD8 T Cell Maturation Occurs Independently of CD8??1  

PubMed Central

As memory CD8 T cells form during acute viral infection, several changes in gene expression and function occur, but little is known about the control of this process. It was reported previously that the homodimer CD8?? was involved in generating IL-7R?high memory CD8 T cell precursors, and consequently, protective memory CD8 T cells did not form in animals significantly impaired in CD8?? expression (E8I?/? mice). However, the precise contribution of CD8?? to sustained IL-7R? expression and other memory CD8 T cell-associated changes has not been investigated. We found that IL-7R? expression and generation of memory CD8 T cells that protect against secondary viral infection was considerably normal in E8I?/? animals. Interestingly, virus-specific CD4 T cell responses were elevated, and the relative surface levels of CD8?? in activated T cells were reduced in E8I?/? mice compared with wild-type animals. Our results indicate that memory CD8 T cell development can occur independently of CD8??.

Chandele, Anmol; Kaech, Susan M.



WASH knockout T cells demonstrate defective receptor trafficking, proliferation, and effector function.  


WASH is an Arp2/3 activator of the Wiskott-Aldrich syndrome protein superfamily that functions during endosomal trafficking processes in collaboration with the retromer and sorting nexins, but its in vivo function has not been examined. To elucidate the physiological role of WASH in T cells, we generated a WASH conditional knockout (WASHout) mouse model. Using CD4(Cre) deletion, we found that thymocyte development and naive T cell activation are unaltered in the absence of WASH. Surprisingly, despite normal T cell receptor (TCR) signaling and interleukin-2 production, WASHout T cells demonstrate significantly reduced proliferative potential and fail to effectively induce experimental autoimmune encephalomyelitis. Interestingly, after activation, WASHout T cells fail to maintain surface levels of TCR, CD28, and LFA-1. Moreover, the levels of the glucose transporter, GLUT1, are also reduced compared to wild-type T cells. We further demonstrate that the loss of surface expression of these receptors in WASHout cells results from aberrant accumulation within the collapsed endosomal compartment, ultimately leading to degradation within the lysosome. Subsequently, activated WASHout T cells experience reduced glucose uptake and metabolic output. Thus, we found that WASH is a newly recognized regulator of TCR, CD28, LFA-1, and GLUT1 endosome-to-membrane recycling. Aberrant trafficking of these key T cell proteins may potentially lead to attenuated proliferation and effector function. PMID:23275443

Piotrowski, Joshua T; Gomez, Timothy S; Schoon, Renee A; Mangalam, Ashutosh K; Billadeau, Daniel D



Implication of ?? T cells in the human immune response to cytomegalovirus  

PubMed Central

In normal individuals, ?? T cells account for less than 6% of total peripheral T lymphocytes and mainly express T-cell receptor (TCR) V?2-V?9 chains. We have previously observed a dramatic expansion of ?? T cells in the peripheral blood of renal allograft recipients only when they developed cytomegalovirus (CMV) infection. This increase was long lasting (more than 1 year), was associated with an activation of ?? T cells, and concerned only V?1 or V?3 T-cell subpopulations. Analysis of ?? TCR junctional diversity revealed that CMV infection in these patients was accompanied by (a) a marked restriction of CDR3 size distribution in V?3 and, to a lesser extent, in V?1 chains; and (b) a selective expansion of V?1 cells bearing recurrent junctional amino acid motifs. These features are highly suggestive of an in vivo antigen-driven selection of ?? T-cell subsets during the course of CMV infection. Furthermore, V?1 and V?3 T cells from CMV-infected kidney recipients were able to proliferate in vitro in the presence of free CMV or CMV-infected fibroblast lysates but not uninfected or other herpes virus–infected fibroblast lysates. This in vitro expansion was inhibited by anti-?? TCR mAb’s. These findings suggest that a population of ?? T cells might play an important role in the immune response of immunosuppressed patients to CMV infection.

Dechanet, Julie; Merville, Pierre; Lim, Annick; Retiere, Christelle; Pitard, Vincent; Lafarge, Xavier; Michelson, Susan; Meric, Claude; Hallet, Marie-Martine; Kourilsky, Philippe; Potaux, Luc; Bonneville, Marc; Moreau, Jean-Francois



The T-cell receptor  

SciTech Connect

This book contains 38 papers. Some of the titles are: Human T-cell receptor genes; Diversity, polymorphism, and a physical map of the {Beta} locus; T cell receptor {Beta}-chain genes; Organization of the human T cell rearranging {gamma} genes (TRG{gamma}); Genetic recombination within T cell receptor alpha and beta chain gene complexes; and The most primitive vertebrate genomes have sequences related to mammalian T-cell receptor genes.

Davis, M.M. (Dept. of Medical Microbiology, Stanford Univ., Stanford, CA (US)); Kappler, J. (Dept. of Medicine, National Jewish Hospital, Denver, CO (US))



The T-cell receptor repertoire of regulatory T cells  

PubMed Central

The CD4+ CD25+ regulatory population of T cells (Treg cells), which expresses the forkhead family transcription factor (Foxp3), is the key component of the peripheral tolerance mechanism that protects us from a variety of autoimmune diseases. Experimental evidence shows that Treg cells recognize a wide range of antigenic specificities with increased reactivity to self antigens, although the affinity of these interactions remains to be further defined. The Treg repertoire is highly diverse with a distinct set of T-cell receptors (TCRs), and yet is overlapping to some extent with the repertoire of conventional T cells (Tconv cells). The majority of Treg cells are generated in the thymus. However, the role of the TCR specificity in directing thymic precursors to become Treg or Tconv cells remains unclear. On the one hand, the higher self reactivity of Treg cells and utilization of different TCRs in Treg and Tconv repertoires suggest that in TCR interactions an initial decision is made about the ‘suitability’ of a developing thymocyte to become a Treg cell. On the other hand, as Treg cells can recognize a wide range of foreign antigens, have a diverse TCR repertoire, and show some degree of overlap with Tconv cells, the signals through the TCR may be complementary to the TCR-independent process that generates precursors of Treg cells. In this review, we discuss how different features of the Treg repertoire influence our understanding of Treg specificities and the role of self reactivity in the generation of this population.

Pacholczyk, Rafal; Kern, Joanna



T cell-T cell activation in multiple sclerosis.  


Activated T cells are able to stimulate proliferation in resting T cells through an antigen non-specific mechanism. The in vivo usefulness of this T cell-T cell activation is unclear, but it may serve to amplify immune responses. T cell-T cell activation could be involved in the well-documented occurrence of multiple sclerosis (MS) exacerbations following viral infections. Excessive activation via this pathway could also be a factor in the etiology of MS. We tested the hypothesis that excessive T cell-T cell activation occurs in MS patients using in vitro proliferation assays comparing T cells from MS patients to T cells from controls. When tested as responder cells, T cells from MS patients proliferated slightly less after stimulation with previously activated cells than T cells from controls. When tested as stimulator cells, activated cells from MS patients stimulated slightly more non-specific proliferation than activated cells from controls. Neither of these differences were statistically significant. We conclude that T cell proliferation in response to activated T cells is similar in MS and controls. PMID:9372506

Lindsey, J W; Kerman, R H; Wolinsky, J S



?? T cells exhibit multifunctional and protective memory in intestinal tissues.  


The study of T cell memory and the target of vaccine design have focused on memory subsumed by T cells bearing the ?? T cell receptor. Alternatively, ?? T cells are thought to provide rapid immunity, particularly at mucosal borders. Here, we have shown that a distinct subset of mucosal ?? T cells mounts an immune response to oral Listeria monocytogenes (Lm) infection and leads to the development of multifunctional memory T cells capable of simultaneously producing interferon-? and interleukin-17A in the murine intestinal mucosa. Challenge infection with oral Lm, but not oral Salmonella or intravenous Lm, induced rapid expansion of memory ?? T cells, suggesting contextual specificity to the priming pathogen. Importantly, memory ?? T cells were able to provide enhanced protection against infection. These findings illustrate that ?? T cells play a role with hallmarks of adaptive immunity in the intestinal mucosa. PMID:23890071

Sheridan, Brian S; Romagnoli, Pablo A; Pham, Quynh-Mai; Fu, Han-Hsuan; Alonzo, Francis; Schubert, Wolf-Dieter; Freitag, Nancy E; Lefrançois, Leo



Development and function of invariant natural killer T cells producing T(h)2- and T(h)17-cytokines.  


There is heterogeneity in invariant natural killer T (iNKT) cells based on the expression of CD4 and the IL-17 receptor B (IL-17RB), a receptor for IL-25 which is a key factor in T(H)2 immunity. However, the development pathway and precise function of these iNKT cell subtypes remain unknown. IL-17RB?iNKT cells are present in the thymic CD44?/? NK1.1? population and develop normally even in the absence of IL-15, which is required for maturation and homeostasis of IL-17RB?iNKT cells producing IFN-?. These results suggest that iNKT cells contain at least two subtypes, IL-17RB? and IL-17RB? subsets. The IL-17RB?iNKT subtypes can be further divided into two subtypes on the basis of CD4 expression both in the thymus and in the periphery. CD4? IL-17RB?iNKT cells produce T(H)2 (IL-13), T(H)9 (IL-9 and IL-10), and T(H)17 (IL-17A and IL-22) cytokines in response to IL-25 in an E4BP4-dependent fashion, whereas CD4? IL-17RB?iNKT cells are a retinoic acid receptor-related orphan receptor (ROR)?t? subset producing T(H)17 cytokines upon stimulation with IL-23 in an E4BP4-independent fashion. These IL-17RB?iNKT cell subtypes are abundantly present in the lung in the steady state and mediate the pathogenesis in virus-induced airway hyperreactivity (AHR). In this study we demonstrated that the IL-17RB?iNKT cell subsets develop distinct from classical iNKT cell developmental stages in the thymus and play important roles in the pathogenesis of airway diseases. PMID:22346732

Watarai, Hiroshi; Sekine-Kondo, Etsuko; Shigeura, Tomokuni; Motomura, Yasutaka; Yasuda, Takuwa; Satoh, Rumi; Yoshida, Hisahiro; Kubo, Masato; Kawamoto, Hiroshi; Koseki, Haruhiko; Taniguchi, Masaru



T cell-independent development and induction of somatic hypermutation in human IgM+ IgD+ CD27+ B cells.  


IgM(+)IgD(+)CD27(+) B cells from peripheral blood have been described as circulating marginal zone B cells. It is still unknown when and where these cells develop. These IgM(+)IgD(+)CD27(+) B cells exhibit somatic hypermutations (SHMs) in their B cell receptors, but the exact nature of the signals leading to induction of these SHMs remains elusive. Here, we show that IgM(+)IgD(+)CD27(+) B cells carrying SHMs are observed during human fetal development. To examine the role of T cells in human IgM(+)IgD(+)CD27(+) B cell development we used an in vivo model in which Rag2(-/-)gamma(C)(-/-) mice were repopulated with human hematopoietic stem cells. Using Rag2(-/-)gamma(C)(-/-) mice on a Nude background, we demonstrated that development and induction of SHMs of human IgM(+)IgD(+)CD27(+) B cells can occur in a T cell-independent manner. PMID:18695003

Scheeren, Ferenc A; Nagasawa, Maho; Weijer, Kees; Cupedo, Tom; Kirberg, Jörg; Legrand, Nicolas; Spits, Hergen



Epithelial and dendritic cells in the thymic medulla promote CD4+Foxp3+ regulatory T cell development via the CD27-CD70 pathway  

PubMed Central

CD4+Foxp3+ regulatory T cells (Treg cells) are largely autoreactive yet escape clonal deletion in the thymus. We demonstrate here that CD27–CD70 co-stimulation in the thymus rescues developing Treg cells from apoptosis and thereby promotes Treg cell generation. Genetic ablation of CD27 or its ligand CD70 reduced Treg cell numbers in the thymus and peripheral lymphoid organs, whereas it did not alter conventional CD4+Foxp3? T cell numbers. The CD27–CD70 pathway was not required for pre-Treg cell generation, Foxp3 induction, or mature Treg cell function. Rather, CD27 signaling enhanced positive selection of Treg cells within the thymus in a cell-intrinsic manner. CD27 signals promoted the survival of thymic Treg cells by inhibiting the mitochondrial apoptosis pathway. CD70 was expressed on Aire? and Aire+ medullary thymic epithelial cells (mTECs) and on dendritic cells (DCs) in the thymic medulla. CD70 on both mTECs and DCs contributed to Treg cell development as shown in BM chimera experiments with CD70-deficient mice. In vitro experiments indicated that CD70 on the CD8?+ subset of thymic DCs promoted Treg cell development. Our data suggest that mTECs and DCs form dedicated niches in the thymic medulla, in which CD27–CD70 co-stimulation rescues developing Treg cells from apoptosis, subsequent to Foxp3 induction by TCR and CD28 signals.

Coquet, Jonathan M.; Ribot, Julie C.; Babala, Nikolina; Middendorp, Sabine; van der Horst, Gerda; Xiao, Yanling; Neves, Joana F.; Fonseca-Pereira, Diogo; Jacobs, Heinz; Pennington, Daniel J.; Silva-Santos, Bruno



Characterization and modulation of sex steroid metabolizing activity in normal human keratinocytes in primary culture and HaCaT cells  

Microsoft Academic Search

Skin, the largest organ of the human body, synthesizes active sex steroids from adrenal C19 precursor steroids. Normal human breast epidermal keratinocytes in primary culture were used to evaluate the enzymatic activities responsible for the formation and degradation of active androgens and estrogens during keratinocyte differentiation. Enzymatic activities, including 3?-hydroxysteroid dehydrogenase\\/?5-?4 isomerase (3?-HSD), 17?-hydroxysteroid dehydrogenase (17?-HSD), 5?-reductase and 3?-hydroxysteroid dehydrogenase

Sébastien Gingras; Carl Turgeon; Nancy Brochu; Penny Soucy; Fernand Labrie; Jacques Simard



Generation of colitogenic Th17 CD4 T cells is enhanced by IL-17+?? T cells  

PubMed Central

Th17 cells have been implicated in the pathogenesis of colitis; however, a cellular mechanism by which colitogenic Th17 immunity arises in vivo remains unclear. In this study, we report that a subset of IL-17+?? T cells plays a crucial role in enhancing in vivo Th17 differentiation and T cell-mediated colitis. TCR?-/- mice were highly susceptible to T cell-mediated colitis, while TCR??-/- mice were resistant to the disease. Importantly, cotransfer of IL-17+ but not of IL-17-?? T cells with CD4 T cells was sufficient to enhance Th17 differentiation and induce full-blown colitis in TCR??-/- recipients. Collectively, our results provide a novel function of IL-17+?? T cell subsets in supporting in vivo Th17 differentiation and possibly in fostering the development of intestinal inflammation.

Do, Jeong-su; Visperas, Anabelle; Dong, Chen; Baldwin, William M.; Min, Booki



T-cell-expressed proprotein convertase furin is essential for maintenance of peripheral immune tolerance.  


Furin is one of seven proprotein convertase family members that promote proteolytic maturation of proproteins. It is induced in activated T cells and is reported to process a variety of substrates including the anti-inflammatory cytokine transforming growth factor (TGF)-beta1 (refs 2-4), but the non-redundant functions of furin versus other proprotein convertases in T cells are unclear. Here we show that conditional deletion of furin in T cells allowed for normal T-cell development but impaired the function of regulatory and effector T cells, which produced less TGF-beta1. Furin-deficient T regulatory (Treg) cells were less protective in a T-cell transfer colitis model and failed to induce Foxp3 in normal T cells. Additionally, furin-deficient effector cells were inherently over-active and were resistant to suppressive activity of wild-type Treg cells. Thus, our results indicate that furin is indispensable in maintaining peripheral tolerance, which is due, at least in part, to its non-redundant, essential function in regulating TGF-beta1 production. Targeting furin has emerged as a strategy in malignant and infectious disease. Our results suggest that inhibiting furin might activate immune responses, but may result in a breakdown in peripheral tolerance. PMID:18701887

Pesu, Marko; Watford, Wendy T; Wei, Lai; Xu, Lili; Fuss, Ivan; Strober, Warren; Andersson, John; Shevach, Ethan M; Quezado, Martha; Bouladoux, Nicolas; Roebroek, Anton; Belkaid, Yasmine; Creemers, John; O'Shea, John J



PD-1+ memory phenotype CD4+ T cells expressing C/EBPalpha underlie T cell immunodepression in senescence and leukemia.  


Although altered T cell function plays a part in immunosenescence, the mechanisms remain uncertain. Here we identify a bona fide age-dependent PD-1(+) memory phenotype (MP) CD4(+) T cell subpopulation that hardly proliferates in response to T cell receptor (TCR) stimulation and produces abundant osteopontin at the cost of typical T cell lymphokines. These T cells demonstrate impaired repopulation in Rag2(-/-) mice, but a homeostatic proliferation in gamma-ray-irradiated mice. These T cells also reveal a unique molecular signature, including a strong expression of C/EBPalpha normally expressed in myeloid-lineage cells, with diminished c-Myc and cyclin D1. Transduction of Cebpa in regular CD4(+) T cells inhibited the TCR-mediated proliferation with c-Myc and cyclin D1 repression and caused a striking activation of Spp1 encoding osteopontin along with concomitant repression of T cell lymphokine genes. Although these T cells gradually increase in number with age and become predominant at the senescent stage in normal mice, the generation is robustly accelerated during leukemia. In both conditions, their predominance is associated with the diminution of specific CD4(+) T cell response. The results suggest that global T cell immunodepression in senescence and leukemia is attributable to the increase in PD-1(+) MP CD4(+) T cells expressing C/EBPalpha. PMID:19805226

Shimatani, Kenichiro; Nakashima, Yasuhiro; Hattori, Masakazu; Hamazaki, Yoko; Minato, Nagahiro



Defect in regulatory B-cell function and development of systemic autoimmunity in T-cell Ig mucin 1 (Tim-1) mucin domain-mutant mice  

PubMed Central

Tim-1, a type I transmembrane glycoprotein, consists of an IgV domain and a mucin domain. The IgV domain is essential for binding Tim-1 to its ligands, but little is known about the role of the mucin domain, even though genetic association of TIM-1 with atopy/asthma has been linked to the length of mucin domain. We generated a Tim-1–mutant mouse (Tim-1?mucin) in which the mucin domain was deleted genetically. The mutant mice showed a profound defect in IL-10 production from regulatory B cells (Bregs). Associated with the loss of IL-10 production in B cells, older Tim-1?mucin mice developed spontaneous autoimmunity associated with hyperactive T cells, with increased production of IFN-? and elevated serum levels of Ig and autoantibodies. However, Tim-1?mucin mice did not develop frank systemic autoimmune disease unless they were crossed onto the Fas-mutant lpr mice on a C57BL/6 background. Tim-1?mucinlpr mice developed accelerated and fulminant systemic autoimmunity with accumulation of abnormal double-negative T cells and autoantibodies to a number of lupus-associated autoantigens. Thus, Tim-1 plays a critical role in maintaining suppressive Breg function, and our data also demonstrate an unexpected role of the Tim-1 mucin domain in regulating Breg function and maintaining self-tolerance.

Xiao, Sheng; Brooks, Craig R.; Zhu, Chen; Wu, Chuan; Sweere, Johanna M.; Petecka, Sonia; Yeste, Ada; Quintana, Francisco J.; Ichimura, Takaharu; Sobel, Raymond A.; Bonventre, Joseph V.; Kuchroo, Vijay K.



The Retinoic Acid-Metabolizing Enzyme Cyp26b1 Regulates CD4 T Cell Differentiation and Function  

PubMed Central

The vitamin A metabolite retinoic acid (RA) has potent immunomodulatory properties that affect T cell differentiation, migration and function. However, the precise role of RA metabolism in T cells remains unclear. Catabolism of RA is mediated by the Cyp26 family of cytochrome P450 oxidases. We examined the role of Cyp26b1, the T cell-specific family member, in CD4+ T cells. Mice with a conditional knockout of Cyp26b1 in T cells (Cyp26b1?/? mice) displayed normal lymphoid development but showed an increased sensitivity to serum retinoids, which led to increased differentiation under both inducible regulatory T (iTreg) cell- and TH17 cell-polarizing conditions in vitro. Further, Cyp26b1 expression was differentially regulated in iTreg and TH17 cells. Transfer of naïve Cyp26b1?/? CD4+ T cells into Rag1?/? mice resulted in significantly reduced disease in a model of T cell-dependent colitis. Our results show that T cell-specific expression of Cyp26b1 is required for the development of T cell-mediated colitis and may be applicable to the development of therapeutics that target Cyp26b1 for the treatment of inflammatory bowel disease.

Chenery, Alistair; Burrows, Kyle; Antignano, Frann; Underhill, T. Michael; Petkovich, Martin; Zaph, Colby



The retinoic Acid-metabolizing enzyme cyp26b1 regulates CD4 T cell differentiation and function.  


The vitamin A metabolite retinoic acid (RA) has potent immunomodulatory properties that affect T cell differentiation, migration and function. However, the precise role of RA metabolism in T cells remains unclear. Catabolism of RA is mediated by the Cyp26 family of cytochrome P450 oxidases. We examined the role of Cyp26b1, the T cell-specific family member, in CD4(+) T cells. Mice with a conditional knockout of Cyp26b1 in T cells (Cyp26b1 (-/-) mice) displayed normal lymphoid development but showed an increased sensitivity to serum retinoids, which led to increased differentiation under both inducible regulatory T (iTreg) cell- and TH17 cell-polarizing conditions in vitro. Further, Cyp26b1 expression was differentially regulated in iTreg and TH17 cells. Transfer of naïve Cyp26b1 (-/-) CD4(+) T cells into Rag1 (-/-) mice resulted in significantly reduced disease in a model of T cell-dependent colitis. Our results show that T cell-specific expression of Cyp26b1 is required for the development of T cell-mediated colitis and may be applicable to the development of therapeutics that target Cyp26b1 for the treatment of inflammatory bowel disease. PMID:23991089

Chenery, Alistair; Burrows, Kyle; Antignano, Frann; Underhill, T Michael; Petkovich, Martin; Zaph, Colby



Regulation of T-cell responses by PTEN  

PubMed Central

Summary The phosphoinositide 3-kinase (PI3K) signaling pathway plays a critical role in the development, activation, and homeostasis of T cells by modulating the expression of survival and mitogenic factors in response to a variety of stimuli. Ligation of the antigen receptor, costimulatory molecules, and cytokine receptors activate PI3K, resulting in the production of the lipid second messenger phosphatidylinositol-3,4,5-triphosphate (PIP3). A number of molecules help to regulate the activity of this pathway, including the lipid phosphatase PTEN (phosphatase and tensin homolog deleted on chromosome 10). By limiting the amount of PIP3 available within the cell, PTEN directly opposes PI3K activity and influences the selection of developing thymocytes as well as the activation requirements of mature T cells. T cells with unchecked PI3K activity, as a result of PTEN deficiency, contribute to the development of both autoimmune disease and lymphoma. This review dissects our current understanding of PI3K and PTEN and discusses why appropriate balance of these molecules is necessary to maintain normal T-cell responses.

Buckler, Jodi L.; Liu, Xiaohe; Turka, Laurence A.



Ephrin-B-dependent thymic epithelial cell-thymocyte interactions are necessary for correct T cell differentiation and thymus histology organization: relevance for thymic cortex development.  


Previous analysis on the thymus of erythropoietin-producing hepatocyte kinases (Eph) B knockout mice and chimeras revealed that Eph-Eph receptor-interacting proteins (ephrins) are expressed both on T cells and thymic epithelial cells (TECs) and play a role in defining the thymus microenvironments. In the current study, we have used the Cre-LoxP system to selectively delete ephrin-B1 and/or ephrin-B2 in either thymocytes (EfnB1(thy/thy), EfnB2(thy/thy), and EfnB1(thy/thy)EfnB2(thy/thy) mice) or TECs (EfnB1(tec/tec), EfnB2(tec/tec), and EfnB1(tec/tec)EfnB2(tec/tec) mice) and determine the relevance of these Eph ligands in T cell differentiation and thymus histology. Our results indicate that ephrin-B1 and ephrin-B2 expressed on thymocytes play an autonomous role in T cell development and, expressed on TECs, their nonautonomous roles are partially overlapping. The effects of the lack of ephrin-B1 and/or ephrin-B2 on either thymocytes or TECs are more severe and specific on thymic epithelium, contribute to the cell intermingling necessary for thymus organization, and affect cortical TEC subpopulation phenotype and location. Moreover, ephrin-B1 and ephrin-B2 seem to be involved in the temporal appearance of distinct cortical TECs subsets defined by different Ly51 levels of expression on the ontogeny. PMID:23408838

Cejalvo, Teresa; Munoz, Juan J; Tobajas, Esther; Fanlo, Lucía; Alfaro, David; García-Ceca, Javier; Zapata, Agustín



ICAM-1-Dependent Homotypic Aggregates Regulate CD8 T Cell Effector Function and Differentiation during T Cell Activation.  


A hallmark of T cell activation in vitro and in vivo is the clustering of T cells with each other via interaction of the LFA-1 integrin with ICAM-1. The functional significance of these homotypic aggregates in regulating T cell function remains unknown. We used an APC-free in vitro activation system to demonstrate that stimulation of purified naive CD8 T cells results in enhanced expression of ICAM-1 on T cells that is sustained by the inflammatory cytokine IL-12 and associated with robust T cell aggregates. ICAM-1-deficient CD8 T cells proliferate normally but demonstrate a striking failure to aggregate. Interestingly, loss of ICAM-1 expression results in elevated levels of IFN-? and granzyme B, as well as enhanced cytotoxicity. Similar results were obtained when anti-LFA-1 Ab was used to block the clustering of wild-type T cells. ICAM-1 ligation is not required for IFN-? regulation, as clustering of ICAM-1-deficient CD8 T cells with wild-type T cells reduces IFN-? expression. Analysis using a fluorescent reporter that monitors TCR signal strength indicates that T cell clustering limits T cell exposure to Ag during activation. Furthermore, T cell clustering promotes the upregulation of the CTLA-4 inhibitory receptor and the downregulation of eomesodermin, which controls effector molecule expression. Activation of ICAM-1-deficient CD8 T cells in vivo results in an enhanced percentage of KLRG-1(+) T cells indicative of short-lived effectors. These results suggest that T cell clustering represents a mechanism that allows continued proliferation but regulates T cell effector function and differentiation. PMID:23997225

Zumwalde, Nicholas A; Domae, Eisuke; Mescher, Matthew F; Shimizu, Yoji



Regulatory T Cells in Radiotherapeutic Responses  

PubMed Central

Radiation therapy (RT) can extend its influence in cancer therapy beyond what can be attributed to in-field cytotoxicity by modulating the immune system. While complex, these systemic effects can help tip the therapeutic balance in favor of treatment success or failure. Engagement of the immune system is generally through recognition of damage-associated molecules expressed or released as a result of tumor and normal tissue radiation damage. This system has evolved to discriminate pathological from physiological forms of cell death by signaling “danger.” The multiple mechanisms that can be evoked include a shift toward a pro-inflammatory, pro-oxidant microenvironment that can promote maturation of dendritic cells and, in cancer treatment, the development of effector T cell responses to tumor-associated antigens. Control over these processes is exerted by regulatory T cells (Tregs), suppressor macrophages, and immunosuppressive cytokines that act in consort to maintain tolerance to self, limit tissue damage, and re-establish tissue homeostasis. Unfortunately, by the time RT for cancer is initiated the tumor-host relationship has already been sculpted in favor of tumor growth and against immune-mediated mechanisms for tumor regression. Reversing this situation is a major challenge. However, recent data show that removal of Tregs can tip the balance in favor of the generation of radiation-induced anti-tumor immunity. The clinical challenge is to do so without excessive depletion that might precipitate serious autoimmune reactions and increase the likelihood of normal tissue complications. The selective modulation of Treg biology to maintain immune tolerance and control of normal tissue damage, while releasing the “brakes” on anti-tumor immune responses, is a worthy aim with promise for enhancing the therapeutic benefit of RT for cancer.

Schaue, Dorthe; Xie, Michael W.; Ratikan, Josephine A.; McBride, William H.



[Adult T-cell leukemia-lymphoma developed from an HTLV-1 carrier during treatment of B-cell lymphoma-associated hemophagocytic syndrome].  


A 63-year-old woman was admitted to our hospital with high-grade fever, liver dysfunction, and pancytopenia. Computed tomography of the whole body revealed hepatosplenomegaly but no lymphoadenopaties. Bone marrow aspiration showed infiltrations of CD20-positive large atypical B-lymphocytes with severe hemophagocytosis. Although she was a human T-cell leukemia virus type 1 carrier, the atypical lymphocyte in bone marrow had IgH rearrangement but not TCR rearrangement. From these clinical and laboratory data, the patient was diagnosed as having B-cell lymphoma-associated hemophagocytic syndrome (B-LAHS) and treated with R-CHOP chemotherapy (rituximab, cyclophosphamide, doxorubicin, vincristine and prednisone). After 4 cycles of R-CHOP, she had achieved complete remission. However, increased numbers of CD4+CD25+ flower cells were observed in peripheral blood and HTLV-1 provirus DNA was detected after 5 cycle of R-CHOP. The patient was diagnosed as adult T-cell leukemia-lymphoma (ATL) complicated by B-LAHS. Our observations suggest that continuous immunosuppressive statement for B-cell lymphoma or the chemotherapy against B-LAHS may induce the development of ATL in an HTLV-1 carrier. PMID:23318967

Nagao, Takayo; Takahashi, Naoto; Saitoh, Hirobumi; Noguchi, Shinsuke; Guo, Yong-Mei; Ito, Mitsugu; Watanabe, Atsushi; Fujishima, Naohito; Kameoka, Yoshihiro; Tagawa, Hiroyuki; Hirokawa, Makoto; Sawada, Kenichi



Three-dimensional architecture of the thymus is required to maintain delta-like expression necessary for inducing T cell development.  


The three-dimensional microarchitecture of the thymus plays a unique role in directing T cell lineage commitment and development. This is supported by the fact that, in contrast to fetal thymic organ cultures, thymic stromal cell monolayer cultures (TSMC) fail to support T lymphopoiesis. Nevertheless, OP9-DL1 cell monolayer cultures induce T lineage commitment and differentiation. Thus, the inability of TSMC to support T lymphopoiesis may be due to a loss of Notch ligand expression and/or function during culture. In this study, we report that, in contrast to fetal thymic organ cultures, TSMC fail to maintain expression of the Notch ligands, Delta-like (Dll) 1 and Dll4, and concomitantly lose the ability to support T lymphopoiesis. Importantly, ectopic re-expression of Dll1 or Dll4 is sufficient to restore the ability of TSMC to support T lymphopoiesis. These findings demonstrate that maintenance of endogenous Dll1 or Dll4 expression by thymic stromal cells is required for the commitment and differentiation of T cells in the absence of a three-dimensional microenvironment. PMID:16393955

Mohtashami, Mahmood; Zúñiga-Pflücker, Juan Carlos



Unchecked CD70 expression on T cells lowers threshold for T-cell activation in rheumatoid arthritis1  

PubMed Central

Rheumatoid arthritis (RA) is characterized by premature immune aging with accumulation of degenerate T cells deficient for CD28. Gene expression profiling of CD4+CD28? and CD4+CD28+ T cells to discover disease-promoting activities of CD28? T cells identified expression of CD70 as a most striking difference. Hence, CD70 was significantly more expressed in CD4 T cells from RA patients compared to age-matched controls (P<0.006). The underlying mechanism was a failure to repress CD70 expression after activation-dependent induction. This defect in RA was not related to differential promoter demethylation. CD70 on bystander CD4+CD28? T cells functioned by lowering the threshold for T-cell activation; admixture of CD4+CD28? T cells augmented TCR-induced responses of autologous naïve CD4+CD28+ T cells, particularly of low avidity T cells. The data support a model where CD70 expressed on T cells causes degeneracy in T-cell responses and undermines tolerance mechanisms that normally control T-cell autoreactivity.

Lee, Won-Woo; Yang, Zhi-Zhang; Li, Guangjin; Weyand, Cornelia M.; Goronzy, Jorg J.



The repertoire of CD4+ CD28- T cells in rheumatoid arthritis.  

PubMed Central

BACKGROUND: While oligoclonality of circulating CD4- CD8 and of CD8+ T cells is not uncommon, clonal dominance within the CD4 compartment is not frequently found in healthy individuals. In contrast, the majority of patients with rheumatoid arthritis (RA) have clonally expanded CD4+ T cell populations. Previous studies have demonstrated that these clonogenic CD4+ T cells do not express the CD28 molecule. To examine the correlation between CD28 expression and clonal proliferation, we have analyzed the T cell receptor (TCR) diversity of CD4+ CD28- T cells in normal individuals and in RA patients. MATERIAL AND METHODS: The size of the peripheral blood CD4+ CD28- compartment was determined in 30 healthy individuals and 30 RA patients by two-color FACS analysis. In 10 RA patients and five controls with more than 2.5% CD4+ CD28- T cells, TCR BV gene segment usage was analyzed with 19 BV-specific antibodies. Oligoclonality was assessed in sorted CD4+ CD28+ and CD28- T cells using TCR BV-BC-specific polymerase chain reaction and size fractionation. Clonal dominance was confirmed by direct sequencing. RESULTS: The CD4+ CD28- T cell compartment was expanded to more than 2.5% in 70% of the RA patients and 30% of the normal individuals. Compared with the CD4+ CD28+ T cells, the TCR BV gene segment usage among CD4+ CD28- cells was grossly skewed with the dominance of single BV elements. Molecular TCR analysis provided evidence for oligoclonality in 17 of 21 expanded BV elements. In two unrelated RA patients who shared both HLA-DRB1 alleles, the TCR beta-chain sequences of dominant clonotypes were highly conserved. CONCLUSIONS: Oligoclonality is a characteristic feature of CD4+ CD28- T cells which are expanded in some healthy individuals and in the majority of RA patients. The lack of CD28 expression is a common denominator of CD4+, CD8+, and CD4- CD8- T cells prone to develop clonal dominance. The limited TCR diversity of clonal CD4+ CD28- populations in RA patients suggests that these T cells recognize a limited spectrum of antigens. The fact that the majority of individuals with marked expansions and oligoclonality of CD4+ CD28- T cells are RA patients suggests a role for these unusual lymphocytes in the pathogenetic events leading to RA. Images FIG. 2 FIG. 3 FIG. 4

Schmidt, D.; Martens, P. B.; Weyand, C. M.; Goronzy, J. J.



T Cell Activity and Cytokine Production in X-Linked Agammaglobulinemia: Implications for Vaccination Strategies  

Microsoft Academic Search

In the 5 X-linked agammaglobulinemia (XLA) patients studied we show that memory T cells are present and that T lymphocytes proliferate normally to mitogens, monoclonal antibodies and, in particular, to recall antigens demonstrating normal in vivo T cell priming despite the absence of B cells. Furthermore, in vitro T cell activation in response to both T cell receptor-independent and T-cell

Alessandro Plebani; Michael B. Fischer; Antonella Meini; Marzia Duse; Voitech Thon; Martha M. Eibl



Targeting ?? T cells for immunotherapy of HIV disease  

PubMed Central

Disruption of circulating ?? T-cell populations is an early and common outcome of HIV infection. T-cell receptor (TCR)-?2?2 cells (expressing the V?2 and V?2 chains of the ?? TCR) are depleted, even though they are minimally susceptible to direct HIV infection, and exemplify indirect cell depletion mechanisms that are important in the progression to AIDS. Among individuals with common or normally progressing HIV disease, the loss of TCR-?2?2 cells has a broad impact on viral immunity, control of opportunistic pathogens and resistance to malignant disease. Advanced HIV disease can result in complete loss of TCR-?2?2 cells that are not recovered even during antiretroviral therapy with complete virus suppression. However, normal levels of TCR-?2?2 were observed among natural virus suppressors (low or undetectable virus without antiretroviral therapy) irrespective of their MHC haplotype, consistent with their disease-free status. The pattern of loss and recovery of TCR-?2?2 cells revealed their unique features and functional capacities, and encourage the development of immune-based therapies to activate and expand this T-cell subset. New research has identified drugs that might reconstitute the TCR-?2?2 population, recover their functional contributions, and improve control of HIV replication and disease. Here, we review research on HIV and TCR-?? T cells to highlight the consequences of depleting this subset and the unique features of TCR-?? biology that argue in favor of clinical strategies to reconstitute this T-cell subset in individuals with HIV/AIDS.

Pauza, C David; Riedel, David J; Gilliam, Bruce L; Redfield, Robert R



T cell Surveillance of Oncogene-induced Prostate Cancer is Impeded by T Cell-derived TGF-?1 Cytokine  

PubMed Central

Summary Tolerance induction in T cells takes place in most tumors and is thought to account for tumor evasion from immune eradication. Production of the cytokine TGF-? is implicated in immunosuppression, however the cellular mechanism by which TGF-? induces T cell dysfunction remains unclear. Using a transgenic model of prostate cancer, we showed that tumor development was not suppressed by the adaptive immune system, which was associated with heightened TGF-? signaling in T cells from the tumor-draining lymph nodes. Blockade of TGF-? signaling in T cells enhanced tumor antigen-specific T cell responses, and inhibited tumor development. Surprisingly, T cell- but not Treg cell-specific ablation of TGF-?1 was sufficient to augment T cell cytotoxic activity and blocked tumor growth and metastases. These findings reveal that T cell production of TGF-?1 is an essential requirement for tumors to evade immunosurveillance independent of TGF-? produced by tumors.

Donkor, Moses K.; Sarkar, Abira; Savage, Peter A.; Franklin, A.; Johnson, Linda K.; Jungbluth, Achim A.; Allison, James P.; Li, Ming O.



T Cell Intrinsic NOD2 Is Dispensable for CD8 T Cell Immunity  

PubMed Central

NOD2 is an intracellular pattern recognition receptor that provides innate sensing of bacterial muramyl dipeptide by host cells, such as dendritic cells, macrophages and epithelial cells. While NOD2's role as an innate pathogen sensor is well established, NOD2 is also expressed at low levels in T cells and there are conflicting data as to whether NOD2 plays an intrinsic role in T cell function. Here we show that following adoptive transfer into WT hosts, NOD2?/? OT-I T cells show a small decrease in the number of OVA-specific CD8 T cells recovered at the peak of the response to respiratory influenza virus infection. On the other hand, no such defect was observed upon intranasal immunization with a replication defective adenovirus carrying the OVA epitope recognized by OT-I, or when OVA was delivered with LPS subcutaneously, or when influenza-OVA was delivered intraperitoneally. Thus we observed a selective defect in NOD2-deficient T cell responses only during a live viral infection. Moreover, there was no apparent defect when NOD2?/? OT-I T cells were stimulated in vitro. Finally, this selective defect in recovery of NOD2-deficient CD8 T cells was not observed in a non-transgenic respiratory infection model in which mixed bone marrow chimeras were used such that the NOD2?/? T cells were allowed to develop and respond in a NOD2-sufficient host. Taken together our data indicate that T cell intrinsic NOD2 is not required for CD8 T cell responses to antigen delivered under a variety of conditions in vitro and in vivo. However, CD8 T cells that have developed in the absence of NOD2 show a selective and modest impairment in their response to live respiratory influenza infection.

Lin, Gloria H. Y.; Wortzman, Michael E.; Girardin, Stephen E.; Philpott, Dana J.; Watts, Tania H.



Regulatory functions of ?? T cells.  


?? T cells account for approximately 5% of peripheral blood T cells but are more abundant in mucosal tissue. Based on the recognized ligands and their general lack of MHC restriction, ?? T cells are considered as unconventional T cells that link innate and adaptive immunity. ?? T cells produce a diverse range of cytokines, exert cytotoxic effector function, can act as antigen-presenting cells, and display regulatory activity. Here we review the current knowledge on the regulatory functions of murine and human ?? T cells. Some ?? T cells produce inhibitory cytokines such as transforming growth factor-? but ?? T cells can utilize additional regulatory mechanisms. By subverting regulatory T cells (Treg) through induction of Treg apoptosis or cytokine-dependent reversal of Treg activity, however, ?? T cells can also enhance effector T cell activity and thereby contribute to autoimmunity. A more precise understanding of the plasticity of regulatory ?? T cells is required to specifically identify strategies for intentional modulation of their beneficial or detrimental regulatory activity. PMID:23481270

Kabelitz, Dieter; Peters, Christian; Wesch, Daniela; Oberg, Hans-Heinrich



A Variable CD3+ T-Cell Frequency in Peripheral Blood Lymphocytes Associated with Type 1 Diabetes Mellitus Development in the LEW.1AR1-iddm Rat  

PubMed Central

Purpose The LEW.1AR1-iddm rat is an animal model of human type 1 diabetes mellitus (T1DM), which arose through a spontaneous mutation within the MHC-congenic inbred strain LEW.1AR1 (RT1r2). In contrast to the diabetes-resistant LEW.1AR1 background strain in LEW.1AR1-iddm rats a highly variable T-cell frequency could be observed in peripheral blood lymphocytes (PBLs). Methods In this study we therefore characterised the T-cell repertoire within the PBLs of the two strains by flow cytometry analysis and identified the CD3+ T-cell phenotype and its possible linkage to diabetes susceptibility. To map loci conferring susceptibility to variable CD3+ T-cell frequency, backcross strains (N2) were generated with the genetically divergent BN and PAR rats for microsatellite analysis. Results The LEW.1AR1-iddm rat strain was characterised by a higher variability of CD3+ T-cells in PBLs along with a slightly decreased mean value compared to the LEW.1AR1 background strain. The reason for this reduction was a decrease in the CD4+ T-cell count while the CD8+ T-cell proportion remained unchanged. However, both T-cell subpopulations showed a high variability. This resulted in a lower CD4+/CD8+ T-cell ratio than in LEW.1AR1 rats. Like LEW.1AR1-iddm rats all animals of the backcross populations, N2 BN and N2 PAR rats, also showed large variations of the CD3+ T-cell frequency. The phenotype of variable CD3+ T-cell frequency mapped to the telomeric region of chromosome 1 (RNO1), which is identical with the already known Iddm8 diabetes susceptibility region. The data indicate that a variable CD3+ T-cell frequency in PBLs is genetically linked to diabetes susceptibility in the LEW.1AR1-iddm rat. Conclusion The T-cell variability in PBLs could be related to the previously reported imbalance between regulatory and effector T-cell populations which results in beta-cell autoimmunity. Since similar T-cell phenotypes have also been described in human T1DM the identification of the functional role of the observed variable CD3+ T-cell frequency may help to understand the mechanisms of autoimmunity in T1DM.

Arndt, Tanja; Jorns, Anne; Weiss, Heike; Tiedge, Markus; Hedrich, Hans-Jurgen; Lenzen, Sigurd; Wedekind, Dirk



T-cell Subset Regulation in Atopy  

Microsoft Academic Search

Presentation of processed allergen by antigen-presenting cells to T-helper (Th) lymphocytes, which is influenced costimulatory\\u000a signals, cytokines, chemokines, and regulatory T cells (Tregs), determines the development of different types of T-cell immunity.\\u000a The discovery of Tregs revolutionized the primary concepts of immune regulation interpreted within the framework of a binary\\u000a Th1\\/Th2 paradigm. Tregs play a central role in the maintenance

Marek Jutel; Cezmi A. Akdis



Partial activation precedes apoptotic death in T cells harboring an IAN gene mutation.  


The Biobreeding diabetes-prone rat suffers from a profound peripheral lymphopenia and yet succumbs to a T cell-dependent autoimmune disease. Lymphopenia segregates with a mutated chromosomal locus, termed lyp, recently identified as a frameshift mutation in IAN4. Others have correlated loss of IAN4 function with decreased mitochondrial integrity resulting in T cell apoptosis. Here we report that IAN4-/- T cells enter a state similar to that of partial activation wherein they down-regulate CD62L and undergo incomplete blasting yet do not progress through mitosis. When given a strong stimulus, this partial activation phenotype can be overcome. This phenotype can be recapitulated in wild-type T cells through suboptimal stimulation. The phenotype is not simply a reaction to the lymphopenic environment, as spontaneous CD62L down-regulation occurs in mature single-positive medullary thymocytes that develop within a non-lymphopenic environment, and normal T cells do not undergo similar blasting when parked in a lymphopenic environment. Finally, we show that IAN4-/- T cells are more readily triggered via TCR stimulation. Thus, in addition to their role in apoptosis, IAN family members may also play a role in regulating the T cell activation state through modulation of TCR signaling strength. PMID:15307172

Lang, Julie A; Kominski, Douglas; Bellgrau, Donald; Scheinman, Robert I



Cre-loxP-Mediated Recombination between the SIL and SCL Genes Leads to a Block in T-Cell Development at the CD4-CD8- to CD4+CD8+ Transition1  

PubMed Central

In the most common form of stem cell leukemia (SCL) gene rearrangement, an interstitial deletion of 82 kb brings SCL under the control of regulatory elements that normally govern expression of the ubiquitously expressed SCL interrupting locus (SIL) gene, which is located directly upstream of SCL. To investigate the effect of this fusion in a mouse model, a bacterial artificial chromosome (BAC) clone containing both human SIL and SCL genes was isolated, and loxP sites were inserted into intron 1 of both the SIL and SCL genes, corresponding to the sites at which recombination occurs in human T-cell acute lymphocytic leukemia patients. This BAC clone was used to generate transgenic SILloxloxSCL mice. These transgenic mice were subsequently bred to Lck-Cre mice that express the Cre recombinase specifically in the thymus. The BAC transgene was recombined between the two loxP sites in over 50% of the thymocytes from SILloxloxSCL/Cre double-transgenic mice, bringing the SCL gene under the direct control of SIL regulatory elements. Aberrant SCL gene expression in the thymus was verified by reverse transcription-polymerase chain reaction. Using FACS analysis, we found that mice carrying both SILloxloxSCL and Cre transgenes have increased CD4-/CD8- thymocytes compared with transgene-negative mice. In the spleen, these transgenic mice show a marked reduction in the number of mature CD4+ or CD8+ cells. These results demonstrate that conditional activation of SCL under control of SIL regulatory elements can impair normal T-cell development.

Yue Cheng; Zhenhua Zhang; Slape, Christopher; Aplan, Peter D.



T-cell subset regulation in atopy.  


Presentation of processed allergen by antigen-presenting cells to T-helper (Th) lymphocytes, which is influenced costimulatory signals, cytokines, chemokines, and regulatory T cells (Tregs), determines the development of different types of T-cell immunity. The discovery of Tregs revolutionized the primary concepts of immune regulation interpreted within the framework of a binary Th1/Th2 paradigm. Tregs play a central role in the maintenance of peripheral homeostasis, the establishment of controlled immune responses, and the inhibition of allergen-specific effector cells. Recently, some other T-cell subsets appeared, including Th17 and Th9 cells, which control local tissue inflammation through upregulation of proinflammatory cytokines and chemokines. This review aims to discuss our understanding of the T-cell subset reciprocal interaction in atopy. PMID:21271314

Jutel, Marek; Akdis, Cezmi A



Molecular Aspects of Epithelial ?? T Cell Regulation  

PubMed Central

?? T cells lie at the interface between innate and adaptive immunity, sharing features with both arms of the immune system. The vast majority of ?? T cells reside in epithelial layers of tissues such as skin, gut, lung, tongue and reproductive tract. Here they provide a first line of defense against environmental attack. While the existence of epithelial resident ?? T cells has been known for over 20 years, understanding the molecular events regulating development and function of these cells is still in progress. Here we review recent advances in the field, with a particular emphasis on the ?? T cell population resident in mouse epidermis. These studies have enhanced our knowledge and understanding of the life cycle of this enigmatic population of cells.

Witherden, Deborah A; Havran, Wendy L



ATM Influences the Efficiency of TCR? Rearrangement, Subsequent TCR?-Dependent T Cell Development, and Generation of the Pre-Selection TCR? CDR3 Repertoire  

PubMed Central

Generation and resolution of DNA double-strand breaks is required to assemble antigen-specific receptors from the genes encoding V, D, and J gene segments during recombination. The present report investigates the requirement for ataxia telangiectasia-mutated (ATM) kinase, a component of DNA double-strand break repair, during TCR? recombination and in subsequent TCR?-dependent repertoire generation and thymocyte development. CD4?CD8? double negative stage 2/3 thymocytes from ATM-deficient mice have both an increased frequency of cells with DNA break foci at TCR? loci and reduced V?-DJ? rearrangement. Sequencing of TCR? complementarity-determining region 3 demonstrates that ATM-deficient CD4+CD8+ double positive thymocytes and peripheral T cells have altered processing of coding ends for both in-frame and out-of-frame TCR? rearrangements, providing the unique demonstration that ATM deficiency alters the expressed TCR? repertoire by a selection-independent mechanism. ATMKO thymi exhibit a partial developmental block in DN cells as they negotiate the ?-selection checkpoint to become double negative stage 4 and CD4+CD8+ thymocytes, resulting in reduced numbers of CD4+CD8+ cells. Importantly, expression of a rearranged TCR? transgene substantially reverses this defect in CD4+CD8+ cells, directly linking a requirement for ATM during endogenous TCR? rearrangement to subsequent TCR?-dependent stages of development. These results demonstrate that ATM plays an important role in TCR? rearrangement, generation of the TCR? CDR3 repertoire, and efficient TCR?-dependent T cell development.

Livak, Ferenc; Hodes, Richard J.



Tissue distribution of human gamma delta T cells: no evidence for general epithelial tropism  

Microsoft Academic Search

In man and mice only a small proportion of T cells in the peripheral lymphoid compartment express the gamma delta T cell receptor (TCR). In mice, however, gamma delta T cells comprise the predominant population at particular epithelial sites--in epidermis and epithelia of intestine, reproductive organs, and tongue. The distribution of gamma delta T cells in normal human tissues was

T M Vroom; G Scholte; F Ossendorp; J Borst



CD8 T Cells and Toxoplasma gondii: A New Paradigm  

PubMed Central

CD8 T cells are essential for control of Toxoplasma gondii infection. Once activated they undergo differentiation into short-lived effector and memory precursor effector cells. As effector cells, CD8 T cells exert immune pressure on the parasite via production of inflammatory cytokines and through their cytolytic activity. Once immune control has been established, the parasite encysts and develops into chronic infection regulated by the memory CD8 T-cell population. Several signals are needed for this process to be initiated and for development of fully differentiated memory CD8 T cells. With newly developed tools including CD8 T-cell tetramers and TCR transgenic mice, dissecting the biology behind T. gondii-specific CD8 T-cell responses can now be more effectively addressed. In this paper, we discuss what is known about the signals required for effective T. gondii-specific CD8 T-cell development, their differentiation, and effector function.

Gigley, Jason P.; Bhadra, Rajarshi; Khan, Imtiaz A.



Tissue-resident memory T cells: Local guards of the thymus.  


T-cell surveillance of nonlymphoid tissues has traditionally been ascribed to recirculating memory T cells that continuously patrol the body. Extending this concept, recent evidence suggests that T cells also exist as nonmigratory memory cells that provide local immune protection in a broad range of peripheral tissues, including barrier locations such as skin and mucosa. In this issue of the European Journal of Immunology, Pircher and colleagues [Eur. J. Immunol. 2013. 43: 2295-2304] demonstrate, for the first time, the existence of such permanently tissue-resident CD8(+) memory T (TRM ) cells in a primary lymphoid organ, the thymus. TRM cells in this location provide potent local immunity, which may help to preserve thymic integrity and normal T-cell development in the face of infection with thymus-invading pathogens. PMID:23908099

Mackay, Laura K; Gebhardt, Thomas



Contrasting Roles For All-Trans Retinoic Acid in TGF-ß-mediated Induction of Foxp3 and Il10 Genes in Developing Regulatory T Cells  

Technology Transfer Automated Retrieval System (TEKTRAN)

Extrathymic induction of regulatory T cells (Treg) is essential to the regulation of effector T cell responses in the periphery. TGF-ß has been shown to induce Foxp3-expressing Tregs both in vitro and in vivo. More recently, the vitamin A metabolite, all-trans retinoic acid (at-RA), has been found t...


Massive Apoptosis of Thymocytes in T-Cell-Deficient Id1 Transgenic Mice  

PubMed Central

Id1 is an inhibitor of a group of basic helix-loop-helix transcription factors, collectively called E proteins, which includes E12, E47, E2-2, and HEB. We have generated transgenic mice in which Id1 is specifically expressed in T cells. The total number of thymocytes in these mice is less than 4% of that in wild-type mice. The majority of the transgenic thymocytes are CD4 and CD8 double negative and bear the cell surface markers of multipotent progenitor cells. A small number of thymocytes, however, differentiate into CD4 or CD8 single-positive T cells, which also display different characteristics from their wild-type counterparts. More importantly, apoptotic cells constitute about 50% of the total thymocytes. These apoptotic thymocytes have rearranged their T-cell receptor genes, suggesting that they are differentiating T cells. This finding has raised the possibility that the T-cell deficiency in Id1 transgenic mice is the result of a massive apoptosis of differentiating T cells triggered by Id1 expression as opposed to a developmental block at the earliest progenitor stage. The progenitor cells accumulated in the transgenic mice might have survived because they are not susceptible to the apoptotic signals. Despite the massive cell death of the thymocytes at young ages, Id1 transgenic mice frequently develop T-cell lymphoma later in their life span, and lymphomagenesis appears to occur at different stages of T-cell development. Taken together, our data suggest that E proteins, being the targets of Id1, are essential regulators for normal T-cell differentiation and tumor suppression.

Kim, Dongsoo; Peng, Xiao-Cong; Sun, Xiao-Hong



Identification of Notch target genes in uncommitted T-cell progenitors: No direct induction of a T-cell specific gene program.  


Deregulated Notch signaling occurs in the majority of human T-ALL. During normal lymphoid development, activation of the Notch signaling pathway poses a T-cell fate on hematopoietic progenitors. However, the transcriptional targets of the Notch pathway are largely unknown. We sought to identify Notch target genes by inducing Notch signaling in human hematopoietic progenitors using two different methods: an intracellular signal through transfection of activated Notch and a Notch-receptor dependent signal by interaction with its ligand Delta1. Gene expression profiles were generated and evaluated with respect to expression profiles of immature thymic subpopulations. We confirmed HES1, NOTCH1 and NRARP as Notch target genes, but other reported Notch targets, including the genes for Deltex1, pre-T-cell receptor alpha and E2A, were not found to be differentially expressed. Remarkably, no induction of T-cell receptor gene rearrangements or transcription of known T-cell specific genes was found after activation of the Notch pathway. A number of novel Notch target genes, including the transcription factor TCFL5 and the HOXA cluster, were identified and functionally tested. Apparently, Notch signaling is essential to open the T-cell pathway, but does not initiate the T-cell program itself. PMID:16990763

Weerkamp, F; Luis, T C; Naber, B A E; Koster, E E L; Jeannotte, L; van Dongen, J J M; Staal, F J T



Phenotypic CD8+ T cell diversification occurs before, during, and after the first T cell division.  


Effector T cell responses rely on a phenotypically and functionally heterogeneous population of cells. Whether this diversity is programmed before clonal expansion or in later phases as a result of stochastic events or asymmetric cell division is not fully understood. In this study, we first took advantage of a sensitive in vitro assay to analyze the composition of single CD8(+) T cell progenies. Heterogeneity was predominantly observed between progenies of distinct clones, but could also be detected within individual progenies. Furthermore, by physically isolating daughter cells of the first T cell division, we showed that differences in paired daughter cell progenies contributed to intraclonal diversification. Finally, we developed an in vivo limiting dilution assay to compare individual T cell progenies following immunization. We provided evidence for simultaneous intraclonal and interclonal diversification in vivo. Our results support the idea that T cell diversification is a continuous process, initiated before clonal expansion and amplified during the first and subsequent cell divisions. PMID:23836060

Lemaître, Fabrice; Moreau, Hélène D; Vedele, Laura; Bousso, Philippe



?c deficiency precludes CD8+ T cell memory despite formation of potent T cell effectors  

PubMed Central

Several cytokines (including IL-2, IL-7, IL-15, and IL-21) that signal through receptors sharing the common ? chain (?c) are critical for the generation and peripheral homeostasis of naive and memory T cells. Recently, we demonstrated that effector functions fail to develop in CD4+ T cells that differentiate in the absence of ?c. To assess the role of ?c cytokines in cell-fate decisions that condition effector versus memory CD8+ T cell generation, we compared the response of CD8+ T cells from ?c+ or ?c? P14 TCR transgenic mice after challenge with lymphocytic choriomeningitis virus. The intrinsic IL-7-dependent survival defect of ?c? naive CD8+ T cells was corrected by transgenic expression of human Bcl-2. We demonstrated that although ?c-dependent signals are dispensable for the initial expansion and the acquisition of cytotoxic functions following antigenic stimulation, they condition the terminal proliferation and differentiation of CD8+ effector T cells (i.e., KLRG1high CD127low short-lived effector T cells) via the transcription factor, T-bet. Moreover, the ?c-dependent signals that are critical for memory T cell formation are not rescued by Bcl2 overexpression. Together, these data reveal an unexpected divergence in the requirement for ?c cytokines in the differentiation of CD4+ versus CD8+ cytotoxic T lymphocytes.

Decaluwe, Helene; Taillardet, Morgan; Corcuff, Erwan; Munitic, Ivana; Law, Helen K. W.; Rocha, Benedita; Riviere, Yves; Di Santo, James P.