bluuebunny/crossref_metadata_2025_split huggingface dataset:
Estradiol Acts Directly on Bone Marrow Myeloid Progenitors to Differentially Regulate GM-CSF or Flt3 Ligand-Mediated Dendritic Cell Differentiation
Authors: Carreras Esther , Turner Sean , Paharkova-Vatchkova Vladislava , Mao Allen , Dascher Christopher , Kovats Susan 
Published: April 2014

AbstractEstrogen receptor (ER) ligands modulate hemopoiesis and immunity in the normal state, during autoimmunity, and after infection or trauma. Dendritic cells (DC) are critical for initiation of innate and adaptive immune responses. We demonstrate, using cytokine-driven culture models of DC differentiation, that 17-β-estradiol exerts opposing effects on differentiation mediated by GM-CSF and Flt3 ligand, the two cytokines that regulate DC differentiation in vivo. We also show that estradiol acts on the same highly purified Flt3+ myeloid progenitors (MP) to differentially regulate the DC differentiation in each model. In GM-CSF-supplemented cultures initiated from MP, physiological amounts of estradiol promoted differentiation of Langerhans-like DC. Conversely, in Flt3 ligand-supplemented cultures initiated from the same MP, estradiol inhibited cell survival in a dose-dependent manner, thereby decreasing the yield of plasmacytoid and conventional myeloid and lymphoid DC. Experiments with bone marrow cells from ER-deficient mice and the ER antagonist ICI182,780 showed that estradiol acted primarily via ERα to regulate DC differentiation. Thus, depending on the cytokine environment, pathways of ER signaling and cytokine receptor signaling can differentially interact in the same Flt3+ MP to regulate DC development. Because the Flt3 ligand-mediated differentiation pathway is important during homeostasis, and GM-CSF-mediated pathways are increased by inflammation, our data suggest that endogenous or pharmacological ER ligands may differentially affect DC development during homeostasis and disease, with consequent effects on DC-mediated immunity.
The Effect of Deleting p110δ on the Phenotype and Function of PTEN-Deficient B Cells
Authors: Janas Michelle L. , Hodson Daniel , Stamataki Zania , Hill Sue , Welch Katie , Gambardella Laure , Trotman Lloyd C. , Pandolfi Pier Paolo , Vigorito Elena , Turner Martin 
Published: April 2014

Abstract
Control of the intracellular levels of phosphatidylinositol-(3, 4, 5)-trisphosphate by PI3K and phosphatase and tensin homolog (PTEN) is essential for B cell development and differentiation. Deletion of the PI3K catalytic subunit p110δ leads to a severe reduction in B1 and marginal zone (MZ) B cells, whereas deletion of PTEN results in their expansion. We have examined the relationship between these two molecules by generating mice with a B cell-specific deletion of PTEN (PTENB) and a concurrent germline deletion of p110δ. The expanded B1 cell population of PTENB mice was reduced to normal levels in PTENB/p110δ mutant mice, indicating a critical role for the p110δ isoform in the expansion of B1 cells. However, numbers of MZ B cells in the PTENB/p110δ mutants was intermediate between wild-type and PTENB-deficient mice, suggesting an additional role for other PI3K catalytic isoforms in MZ differentiation. Furthermore, the defective class switch recombination in PTENB B cells was only partially reversed in PTENB/p110δ double mutant B cells. These results demonstrate an epistatic relationship between p110δ and PTEN. In addition, they also suggest that additional PI3K catalytic subunits contribute to B cell development and function.
Accumulation of Effector CD4 T Cells during Type 2 Immune Responses Is Negatively Regulated by Stat6
Authors: King Susan B. S. , Knorn Anna M. , Ohnmacht Caspar , Voehringer David 
Published: April 2014

Abstract
Th2 cells are important effector cells during allergic disorders and parasite infections. Efficient differentiation of Th2 cells requires signaling via the IL-4R and the transcription factor Stat6. Stat6 is further implicated in Th2 cell recruitment to the lung and might be required for the survival of memory Th2 cells. We analyzed the role of Stat6 in T cell expansion, survival, and recruitment to the lung using competitive adoptive transfer experiments and infection with the helminth parasite Nippostrongylus brasiliensis. Stat6 was not required in T cells or other cell types for recruitment of in vivo-generated Th2 cells to the lung. Functional analysis of Th2 memory cells revealed that Stat6 signaling in CD4 T cells was dispensable for memory cell generation, expansion, and cytokine secretion. However, Stat6-deficient T cells survived better than wild-type T cells, resulting in higher accumulation in the bronchoalveolar lavage, lung, and lymph nodes. This demonstrates that effector T cell expansion is negatively controlled by a novel Stat6-dependent mechanism which probably serves to limit the number of effector T cells during the acute phase of the immune response and thereby lowers the risk of bystander toxicity against healthy tissues.
ICOS Controls the Pool Size of Effector-Memory and Regulatory T Cells
Authors: Burmeister Yvonne , Lischke Timo , Dahler Anja C. , Mages Hans Werner , Lam Kong-Peng , Coyle Anthony J. , Kroczek Richard A. , Hutloff Andreas 
Published: April 2014

Abstract
ICOS is an important regulator of T cell effector function. ICOS-deficient patients as well as knockout mice show severe defects in T cell-dependent B cell responses. Several in vitro and in vivo studies attributed this phenomenon to impaired up-regulation of cell surface communication molecules and cytokine synthesis by ICOS-deficient T cells. However, we now could show with Ag-specific T cells in a murine adoptive transfer system that signaling via ICOS does not significantly affect early T cell activation. Instead, ICOS substantially contributes to the survival and expansion of effector T cells upon local challenge with Ag and adjuvant. Importantly, the observed biological function of ICOS also extends to FoxP3+ regulatory T cells, as can be observed after systemic Ag delivery without adjuvant. In line with these findings, absence of ICOS under homeostatic conditions of nonimmunized mice leads to a reduced number of both effector-memory and FoxP3+ regulatory T cells. Based on these results, we propose a biological role for ICOS as a costimulatory, agonistic molecule for a variety of effector T cells with differing and partly opposing functional roles. This concept may reconcile a number of past in vivo studies with seemingly contradictory results on ICOS function.
Essential Role of CD8+CD122+ Regulatory T Cells in the Recovery from Experimental Autoimmune Encephalomyelitis
Authors: Lee Young-Ho , Ishida Yoshiyuki , Rifa’i Muhaimin , Shi Zhe , Isobe Ken-ichi , Suzuki Haruhiko 
Published: April 2014

Abstract
Experimental autoimmune encephalomyelitis (EAE) is one of the best-documented animal models of autoimmune disease. We examined the role of CD8+CD122+ regulatory T cells, which we previously identified as naturally occurring regulatory T cells that effectively regulate CD8+ T cells, in EAE. Depletion of CD8+CD122+ regulatory T cells by in vivo administration of anti-CD122 mAb resulted in persistent EAE symptoms. Transfer of CD8+CD122+ regulatory T cells into EAE mice at the peak EAE score clearly improved symptoms, indicating an important role of CD8+CD122+ regulatory T cells in the recovery phase of EAE. This was further confirmed by an increase and a decrease in the number of infiltrating T cells in the CNS and T cell cytokine production in mice that were depleted of or complemented with CD8+CD122+ cells. Furthermore, transfer of preactivated CD8+CD122+ regulatory T cells resulted in diminished EAE symptoms, especially in the recovery phase of EAE. These results elucidate the essential role of CD8+CD122+ regulatory T cells in the recovery phase of EAE and suggest the preventive effect of preactivated CD8+CD122+ regulatory T cells for EAE.
CD4+ T Cells Recognizing a Single Self-Peptide Expressed by APCs Induce Spontaneous Autoimmune Arthritis
Authors: Rankin Andrew L. , Reed Amy J. , Oh Soyoung , Cozzo Picca Cristina , Guay Heath M. , Larkin Joseph , Panarey Laura , Aitken Malinda K. , Koeberlein Brigitte , Lipsky Peter E. , Tomaszewski John E. , Naji Ali , Caton Andrew J. 
Published: April 2014

Abstract
We have examined processes leading to the spontaneous development of autoimmune inflammatory arthritis in transgenic mice containing CD4+ T cells targeted to a nominal Ag (hemagglutinin (HA)) and coexpressing HA driven by a MHC class II promoter. Despite being subjected to multiple tolerance mechanisms, autoreactive CD4+ T cells accumulate in the periphery of these mice and promote systemic proinflammatory cytokine production. The majority of mice spontaneously develop inflammatory arthritis, which is accompanied by an enhanced regional immune response in lymph nodes draining major joints. Arthritis development is accompanied by systemic B cell activation; however, neither B cells nor Ab is required for arthritis development, since disease develops in a B cell-deficient background. Moreover, arthritis also develops in a recombinase activating gene-deficient background, indicating that the disease process is driven by CD4+ T cells recognizing the neo-self HA Ag. These findings show that autoreactive CD4+ T cells recognizing a single self-Ag, expressed by systemically distributed APCs, can induce arthritis via a mechanism that is independent of their ability to provide help for autoantibody production.
Alveolar Epithelial Type II Cells Induce T Cell Tolerance to Specific Antigen
Authors: Lo Bernice , Hansen Soren , Evans Kathy , Heath John K. , Wright Jo Rae 
Published: April 2014

Abstract
The lungs face the immunologic challenge of rapidly eliminating inhaled pathogens while maintaining tolerance to innocuous Ags. A break in this immune homeostasis may result in pulmonary inflammatory diseases, such as allergies or asthma. The observation that alveolar epithelial type II cells (Type II) constitutively express the class II MHC led us to hypothesize that Type II cells play a role in the adaptive immune response. Because Type II cells do not express detectable levels of the costimulatory molecules CD80 and CD86, we propose that Type II cells suppress activation of naive T cells. Purified murine Type II cells were unable to activate T cells to specific Ag or in an alloreactive assay. Although IFN-γ treatment up-regulated class II MHC expression, it did not alter the ability of the Type II cells to activate T cells. Rather, the Type II cells were able to suppress T cells from subsequent activation to specific Ag in an Ag-dependent manner. Priming T cells with Type II cells and Ag resulted in T cells that were suppressed to further activation, even after removal from the Type II cells. Thus, Type II cells of the lung help tolerize T cells to nonpathogenic environmental Ags.
Pregnancy Allows the Transfer and Differentiation of Fetal Lymphoid Progenitors into Functional T and B Cells in Mothers
Authors: Khosrotehrani Kiarash , Leduc Michèle , Bachy Véronique , Huu Sau Nguyen , Oster Michèle , Abbas Aicha , Uzan Serge , Aractingi Sélim 
Published: April 2014

Abstract
T lymphocytes of fetal origin found in maternal circulation after gestation have been reported as a possible cause for autoimmune diseases. During gestation, mothers acquire CD34+CD38+ cells of fetal origin that persist decades. In this study, we asked whether fetal T and B cells could develop from these progenitors in the maternal thymus and bone marrow during and after gestation. RAG−/−-deficient female mice (Ly5.2) were mated to congenic wild-type Ly5.1 mice (RAG+/+). Fetal double-positive T cells (CD4+CD8+) with characteristic TCR and IL-7R expression patterns could be recovered in maternal thymus during the resulting pregnancies. We made similar observations in the thymus of immunocompetent mothers. Such phenomenon was observed overall in 12 of 68 tested mice compared with 0 of 51 controls (p = 0.001). T cells could also be found in maternal spleen and produced IFN-γ in the presence of an allogenic or an Ag-specific stimulus. Similarly, CD19+IgM+ fetal B cells as well as plasma Igs could be found in maternal RAG−/− bone marrow and spleen after similar matings. Our results suggest that during gestation mothers acquire fetal lymphoid progenitors that develop into functional T cells. This fetal cell microchimerism may have a direct impact on maternal health.
CD22 Regulates Time Course of Both B Cell Division and Antibody Response
Authors: Onodera Taishi , Poe Jonathan C. , Tedder Thomas F. , Tsubata Takeshi 
Published: April 2014

AbstractBecause pathogens induce infectious symptoms in a time-dependent manner, a rapid immune response is beneficial for defending hosts from pathogens, especially those inducing acute infectious diseases. However, it is largely unknown how the time course of immune responses is regulated. In this study, we demonstrate that B cells deficient in the inhibitory coreceptor CD22 undergo accelerated cell division after Ag stimulation, resulting in rapid generation of plasma cells and Ab production. This finding indicates that CD22 regulates the time course of B cell responses and suggests that CD22 is a good target to shorten the time required for Ab production, thereby augmenting host defense against acute infectious diseases as “universal vaccination.”
Implication of Matrix Metalloproteinase 7 and the Noncanonical Wingless-Type Signaling Pathway in a Model of Kidney Allograft Tolerance Induced by the Administration of Anti-Donor Class II Antibodies
Authors: Jovanovic Vojislav , Dugast Anne-Sophie , Heslan Jean-Marie , Ashton-Chess Joanna , Giral Magali , Degauque Nicolas , Moreau Anne , Pallier Annaick , Chiffoleau Elise , Lair David , Usal Claire , Smit Helga , Vanhove Bernard , Soulillou Jean-Paul , Brouard Sophie 
Published: April 2014

Abstract
In rats, tolerance to MHC-incompatible renal allografts can be induced by the administration of anti-donor class II Abs on the day of transplantation. In this study we explored the mechanisms involved in the maintenance phase of this tolerance by analyzing intragraft gene expression profiles by microarray in long-term accepted kidneys. Comparison of the gene expression patterns of tolerated to syngeneic kidneys revealed 5,954 differentially expressed genes (p &lt; 0.05). Further analysis of this gene set revealed a key role for the wingless-type (WNT) signaling pathway, one of the pivotal pathways involved in cell regulation that has not yet been implicated in transplantation. Several genes within this pathway were significantly up-regulated in the tolerated grafts, particularly matrix metalloproteinase 7 (MMP7; fold change &gt; 40). Analysis of several other pathway-related molecules indicated that MMP7 overexpression was the result of the noncanonical WNT signaling pathway. MMP7 expression was restricted to vascular smooth muscle cells and was specific to anti-class II Ab-induced tolerance, as it was undetectable in other models of renal and heart transplant tolerance and chronic rejection induced across the same strain combination. These results suggest a novel role for noncanonical WNT signaling in maintaining kidney transplant tolerance in this model, with MMP7 being a key target. Determining the mechanisms whereby MMP7 contributes to transplant tolerance may help in the development of new strategies to improve long-term graft outcome.
Suppression of Mature Dendritic Cell Function by Regulatory T Cells In Vivo Is Abrogated by CD40 Licensing
Authors: Hänig Jens , Lutz Manfred B. 
Published: April 2014

Abstract
The priming of CD4+ effector T cells (Teff) in vivo is induced by mature dendritic cells (DC) and controlled by CD4+CD25+Foxp3+ regulatory T cells (Treg). It remains unclear,however, how Teff priming vs Treg suppression are regulated during Ag presentation by DC in secondary lymphoid organs at the simultaneous presence of Teff and Treg. In this study, we used an peptide-specific DO11.10 TCR-transgenic adoptive transfer model to follow the Teff priming kinetics and the mechanisms of suppression by Treg. Treg activation was slower as compared with Teff and could not influence the early Teff expansion but limited the Teff response leading to lower Teff numbers in the memory phase. DC-Treg cell contacts remained unaltered during suppression by Treg and led to a down-regulation of the costimulatory molecules CD80, CD86, PD-L1, and PD-L2 but not MHC II, CD40, ICOS-L, or CD70 from the mature DC surface. This effect was observed only after DC maturation with TNF or LPS but not after additional CD40 licensing. Together, our data indicate that Treg suppression against nonself Ags in vivo occurs delayed due to the slower Treg response, is mediated to a large extent through DC modulation, but is controlled by the type of DC maturation.
TGF-β Inhibits IL-2 Production and Promotes Cell Cycle Arrest in TCR-Activated Effector/Memory T Cells in the Presence of Sustained TCR Signal Transduction
Authors: Das Lopamudra , Levine Alan D. 
Published: April 2014

AbstractTGF-β signaling is critical for controlling naive T cell homeostasis and differentiation; however, the biological and biochemical changes induced by TGF-β in effector/memory T cells are poorly defined. We show that although TGF-β inhibits effector/memory peripheral blood T lymphoblast proliferation and IL-2 production, the intensity and kinetics for TCR-induced global tyrosine phosphorylation are markedly increased compared with that in untreated cells or naive T cells. After TCR ligation, tyrosine phosphorylation of proximal tyrosine kinases and docking proteins like linker for activation of T cells is maintained for &gt;30 min in TGF-β-primed cells compared with untreated cells where phosphorylation of these targets returned to basal levels by 10 min. Extended phosphorylation of linker for activation of T cells in treated peripheral blood T selectively prolongs ERK 1/2 signaling and phospholipase C-γ1 activation leading to increased Ca2+ flux. A kinase/phosphatase imbalance could not account for extended phosphorylation as CD45R, SHP-1, and SHP-2 expression remains unaltered. The contradiction between prolonged signal transduction and inhibition of proliferation is partially explained by the observation that TGF-β priming results in ERK 1/2-independent p21 induction and decreased cyclin D1 expression leading to accumulation of T cells in G0/G1 phases of the cell cycle and cell cycle arrest. Despite inhibition of T cell function by TGF-β priming, TCR and cytokine signaling pathways are intact and selectively extended, suggesting that suppression in the effector/memory T cell is mediated by reprogramming signal transduction, rather than its inhibition as in the naive T cell.
Homeostasis of the Naive CD4+ T Cell Compartment during Aging
Authors: Kilpatrick Ryan D. , Rickabaugh Tammy , Hultin Lance E. , Hultin Patricia , Hausner Mary Ann , Detels Roger , Phair John , Jamieson Beth D. 
Published: April 2014

AbstractDespite thymic involution, the number of naive CD4+ T cells diminishes slowly during aging, suggesting considerable peripheral homeostatic expansion of these cells. To investigate the mechanisms behind, and consequences of, naive CD4+ T cell homeostasis, we evaluated the age-dependent dynamics of the naive CD4+ T cell subsets CD45RA+CD31+ and CD45RA+CD31−. Using both a cross-sectional and longitudinal study design, we measured the relative proportion of both subsets in individuals ranging from 22 to 73 years of age and quantified TCR excision circle content within those subsets as an indicator of proliferative history. Our findings demonstrate that waning thymic output results in a decrease in CD45RA+CD31+ naive CD4+ T cells over time, although we noted considerable individual variability in the kinetics of this change. In contrast, there was no significant decline in the CD45RA+CD31− naive CD4+ T cell subset due to extensive peripheral proliferation. Our longitudinal data are the first to demonstrate that the CD45RA+CD31+CD4+ subset also undergoes some in vivo proliferation without immediate loss of CD31, resulting in an accumulation of CD45RA+CD31+ proliferative offspring. Aging was associated with telomere shortening within both subsets, raising the possibility that accumulation of proliferative offspring contributes to senescence of the naive CD4+ T cell compartment in the elderly. In contrast, we observed retention of clonal TCR diversity despite peripheral expansion, although this analysis did not include individuals over 65 years of age. Our results provide insight into naive CD4+ T cell homeostasis during aging that can be used to better understand the mechanisms that may contribute to immunosenescence within this compartment.
Kinetic and Mechanistic Requirements for Helping CD8 T Cells
Authors: Agnellini Paola , Wiesel Melanie , Schwarz Katrin , Wolint Petra , Bachmann Martin F. , Oxenius Annette 
Published: April 2014

Abstract
The requirements for the generation of fully competent long-lived memory CD8 T cells and in particular the role and the mechanisms of help from CD4 T cells remain ill-defined. Memory CD8 T cells generated in the absence of CD4 T cell help often have an impaired recall proliferation and are thus unable to confer protection against certain pathogens. However, the timing and the mechanisms involved in the delivery of help are still unclear and differ between various experimental systems. In this study, we investigated the role of CD4 T help in generating memory CD8 T cells in a defined heterologous prime-boost system, consisting of priming with replication incompetent virus-like particles and challenge with recombinant vaccinia virus, both sharing only a common lymphocytic choriomeningitis virus-derived CD8 T cell epitope. We show in this system that delivery of help is only essential during the challenge phase for recall proliferation of memory CD8 T cells. Furthermore, we show that generation of proliferation-competent memory CD8 T cells is independent of CD40 and CCR5 and that in vivo IL-2 supplementation neither during priming nor during challenge was able to rescue recall proliferation of “unhelped” memory CD8 T cells.
Th2 Lymphoproliferative Disorder of Lat
Y136F Mutant Mice Unfolds Independently of TCR-MHC Engagement and Is Insensitive to the Action of Foxp3+ Regulatory T Cells
Authors: Wang Ying , Kissenpfennig Adrien , Mingueneau Michael , Richelme Sylvie , Perrin Pierre , Chevrier Stéphane , Genton Céline , Lucas Bruno , DiSanto James P. , Acha-Orbea Hans , Malissen Bernard , Malissen Marie 
Published: April 2014

Abstract
Mutant mice where tyrosine 136 of linker for activation of T cells (LAT) was replaced with a phenylalanine (LatY136F mice) develop a fast-onset lymphoproliferative disorder involving polyclonal CD4 T cells that produce massive amounts of Th2 cytokines and trigger severe inflammation and autoantibodies. We analyzed whether the LatY136F pathology constitutes a bona fide autoimmune disorder dependent on TCR specificity. Using adoptive transfer experiments, we demonstrated that the expansion and uncontrolled Th2-effector function of LatY136F CD4 cells are not triggered by an MHC class II-driven, autoreactive process. Using Foxp3EGFP reporter mice, we further showed that nonfunctional Foxp3+ regulatory T cells are present in LatY136F mice and that pathogenic LatY136F CD4 T cells were capable of escaping the control of infused wild-type Foxp3+ regulatory T cells. These results argue against a scenario where the LatY136F pathology is primarily due to a lack of functional Foxp3+ regulatory T cells and suggest that a defect intrinsic to LatY136F CD4 T cells leads to a state of TCR-independent hyperactivity. This abnormal status confers LatY136F CD4 T cells with the ability to trigger the production of Abs and of autoantibodies in a TCR-independent, quasi-mitogenic fashion. Therefore, despite the presence of autoantibodies causative of severe systemic disease, the pathological conditions observed in LatY136F mice unfold in an Ag-independent manner and thus do not qualify as a genuine autoimmune disorder.