bluuebunny/crossref_metadata_2025_split huggingface dataset:
Characterization of CCR9 Expression and CCL25/Thymus-Expressed Chemokine Responsiveness During T Cell Development: CD3highCD69+ Thymocytes and γδTCR+ Thymocytes Preferentially Respond to CCL25
Authors: Uehara Shoji , Song Kaimei , Farber Joshua M. , Love Paul E. 
Published: April 2014

AbstractCCR9 mediates chemotaxis of thymocytes in response to CCL25/thymus-expressed chemokine, and its mRNA is selectively expressed in thymus and small intestine, the two known sites of T lymphopoiesis. To examine the expression of CCR9 during lymphocyte development, we generated polyclonal Ab that recognizes murine CCR9. CCR9 was expressed on the majority of immature CD4+CD8+ (double-positive) thymocytes, but not on immature CD4−CD8− (double-negative) thymocytes. CCR9 was down-regulated during the transition of double-positive thymocytes to the CD4+ or CD8+ (single-positive) stage, and only a minor subset of CD8+ lymph node T cells expressed CCR9. All CCR9+ thymocyte subsets migrated in response to CCL25; however, CD69+ thymocytes demonstrated enhanced CCL25-induced migration compared with CD69− thymocytes. Ab-mediated TCR stimulation also enhanced CCL25 responsiveness, indicating that CCL25-induced thymocyte migration is augmented by TCR signaling. Approximately one-half of all γδTCR+ thymocytes and peripheral γδTCR+ T cells expressed CCR9 on their surface, and these cells migrated in response to CCL25. These findings suggest that CCR9 may play an important role in the development and trafficking of both αβTCR+ and γδTCR+ T cells.
Staphylokinase-Specific Cell-Mediated Immunity in Humans
Authors: Warmerdam Petra A. M. , Vanderlick Kristel , Vandervoort Petra , De Smedt Heidi , Plaisance Stéphane , De Maeyer Marc , Collen Désiré 
Published: April 2014

Abstract
Staphylokinase is a highly fibrin-specific clot-dissolving agent that constitutes a promising drug for clinical development. It is of bacterial origin, and the majority of patients develop neutralizing Ab after its administration. Several antigenic regions, recognized by these Ab, have been identified, but the underlying immunogenic features of staphylokinase remain unknown. In this study, we show that staphylokinase is a T cell-dependent Ag, and that an immunological memory may be acquired, even without administration of staphylokinase. Thrombolysis with staphylokinase provokes the proliferation of staphylokinase-specific T lymphocytes, which remain elevated over 10 mo posttreatment. Interestingly, analysis of a large number of staphylokinase-specific T cell clones isolated from 10 unrelated donors revealed only six distinct immunogenic regions in the molecule. Moreover, five of the six regions are recognized by T lymphocytes from several individuals, indicating that these regions are not restricted to a single HLA-DR allele. Therefore, these new insights can guide the design of variants with a lower immunogenic profile in humans.
Classical MHC Class I Genes Composed of Highly Divergent Sequence Lineages Share a Single Locus in Rainbow Trout (Oncorhynchus mykiss)
Authors: Aoyagi Kazuhiko , Dijkstra Johannes M. , Xia Chun , Denda Ikuo , Ototake Mitsuru , Hashimoto Keiichiro , Nakanishi Teruyuki 
Published: April 2014

AbstractThe classical MHC class I genes have been known to be highly polymorphic in various vertebrates. To date, putative allelic sequences of the classical MHC class I genes in teleost fish have been reported in several studies. However, the establishment of their allelic status has been hampered in most cases by the lack of appropriate genomic information. In the present study, using heterozygous and homozygous fish, we obtained classical-type MHC class I sequences of rainbow trout (Oncorhynchus mykiss) and investigated their allelic relationship by gene amplification and Southern and Northern hybridization analyses. The results indicated that all MHC class I sequences we obtained were derived from a single locus. Based on this, a unique polymorphic nature of the MHC class I locus of rainbow trout has been revealed. The mosaic combination of highly divergent ancient sequences in the peptide-binding domains is notable, and the variable nature around the boundary between the α3 and transmembrane domains is unprecedented.
Development and Homeostasis of T Cell Memory in Rhesus Macaque
Authors: Pitcher Christine J. , Hagen Shoko I. , Walker Joshua M. , Lum Richard , Mitchell Bridget L. , Maino Vernon C. , Axthelm Michael K. , Picker Louis J. 
Published: April 2014

AbstractThe rhesus macaque (RM) is a critical animal model for studies of viral pathogenesis and immunity, yet fundamental aspects of their cellular immune response remain poorly defined. One such deficiency is the lack of validated phenotypic signatures for their naive and memory T cell subsets, and the resultant unavailability of accurate information on their memory T cell development, homeostasis, and function. In this study, we report a phenotypic paradigm allowing definitive characterization of these subsets and their comprehensive functional analysis. Naive T cells are optimally delineated by their homogeneous CD95lowCD28highβ7 integrinint (CD4+) or CD95lowCD28intCD11alow (CD8+) phenotypes. This subset 1) was present in blood and secondary lymph tissues, but not effector sites; 2) vastly predominated in the fetal/neonatal immune system, but rapidly diminished with postnatal age; 3) lacked IFN-γ production capability, and specific responses to RM CMV; and 4) demonstrated low in vivo proliferative activity. CD4+ and CD8+ memory subsets were CD95high, but otherwise phenotypically heterogeneous and included all IFN-γ production, RM CMV-specific responses, effector site T cells, and demonstrated high in vivo proliferative activity (∼10 times the naive subset). These analyses also revealed the RM “effector memory” subset within the overall memory population. This population, best defined by lack of CD28 expression, contained the majority of RM CMV-specific cells, was highly enriched in extralymphoid effector sites, and comprised an increasing proportion of total memory cells with age. The effector memory subset demonstrated similar in vivo proliferative activity and survival as CD28+ “central memory” T cells, consistent with independent homeostatic regulation.
Role of STAT6 in IgE Receptor/FcεRI-Mediated Late Phase Allergic Responses of Mast Cells
Authors: Malaviya Ravi , Uckun Fatih M. 
Published: April 2014

Abstract
In this study we show that IgE receptor engagement triggers activation of STAT6 in mast cells. We sought to determine the role of STAT6 activation in IgE receptor-mediated mast cell responses using STAT6 knockout mice. After IgE receptor engagement, bone marrow mast cells from STAT6−/− mice exhibited normal histamine and leukotriene C4 release, but their cytokine release was markedly reduced. In accordance with these in vitro data, IgE/Ag-challenged STAT6−/− mice showed normal early phase, but severely impaired late phase, allergic reactions. These findings provide unprecedented evidence that STAT6 plays a pivotal role in mast cell responses to IgE/Ag st imulation.
Generation of Diversity in the Innate Immune System: Macrophage Heterogeneity Arises from Gene-Autonomous Transcriptional Probability of Individual Inducible Genes
Authors: Ravasi Timothy , Wells Christine , Forest Alistair , Underhill David M. , Wainwright Brandon J. , Aderem Alan , Grimmond Sean , Hume David A. 
Published: April 2014

AbstractMicrobial products such as LPS stimulate macrophages to produce a wide diversity of inducible gene products needed for immediate host defense and priming of an appropriate acquired immune response. In this study, we have examined LPS-inducible gene expression in subclones of a mouse macrophage cell line, RAW264, using cDNA microarrays. Even archetypal target genes such as TNF-α were not induced in all subclones, and there was no absolute correlation between expression of pairs of genes. Nevertheless, the array analysis revealed clusters of genes that were more likely to be coexpressed. RAW264 cells stably transfected with luciferase reporter genes driven by LPS-responsive promoters revealed the same kind of clonal heterogeneity. The results indicate that each LPS-inducible gene has its own inherent probability of activation in response to LPS.
The Membrane Attack Complex of Complement Causes Severe Demyelination Associated with Acute Axonal Injury
Authors: Mead Richard J. , Singhrao Sim K. , Neal James W. , Lassmann H. , Morgan B. Paul 
Published: April 2014

Abstract
Complement is implicated in pathology in the human demyelinating disease multiple sclerosis and in animal models that mimic the demyelination seen in multiple sclerosis. However, the components of the complement system responsible for demyelination in vivo remain unidentified. In this study, we show that C6-deficient (C6−) PVG/c rats, unable to form the membrane attack complex (MAC), exhibit no demyelination and significantly reduced clinical score in the Ab-mediated experimental autoimmune encephalomyelitis model when compared with matched C6-sufficient (C6+) rats. In C6+ rats, perivenous demyelination appeared, accompanied by abundant mononuclear cell infiltration and axonal injury. Neither demyelination nor axonal damage was seen in C6− rats, whereas levels of mononuclear cell infiltration were equivalent to those seen in C6+ rats. Reconstitution of C6 to C6− rats yielded pathology and clinical disease indistinguishable from that in C6+ rats. We conclude that demyelination and axonal damage occur in the presence of Ab and require activation of the entire complement cascade, including MAC deposition. In the absence of MAC deposition, complement activation leading to opsonization and generation of the anaphylatoxins C5a and C3a is insufficient to initiate demyelination.
Prolonged Allograft Survival in TNF Receptor 1-Deficient Recipients Is Due to Immunoregulatory Effects, Not to Inhibition of Direct Antigraft Cytotoxicity
Authors: McKee Charlotte M. , Defina Rachel , He Hongzhen , Haley Kathleen J. , Stone James R. , Perkins David L. 
Published: April 2014

Abstract
TNF-α and lymphotoxin (LT)α have been shown to be important mediators of allograft rejection. TNF-R1 is the principal receptor for both molecules. Mice with targeted genetic deletions of TNF-R1 demonstrate normal development of T and B lymphocytes but exhibit functional defects in immune responses. However, the role of TNF-R1-mediated signaling in solid organ transplant rejection has not been defined. To investigate this question, we performed vascularized heterotopic allogeneic cardiac transplants in TNF-R1-deficient (TNF-R1−/−) and wild-type mice. Because all allografts in our protocol expressed TNF-R1, direct antigraft effects of TNF-α and LTα were not prevented. However, immunoregulatory effects on recipient inflammatory cells by TNF-R1 engagement was eliminated in TNF-R1−/− recipients. In our study, cardiac allograft survival was significantly prolonged in TNF-R1−/− recipients. Despite this prolonged allograft survival, we detected increased levels of CD8 T cell markers in allografts from TNF-R1−/− recipients, suggesting that effector functions, but not T cell recruitment, were blocked. We also demonstrated the inhibition of multiple chemokines and cytokines in allografts from TNF-R1−/− recipients including RANTES, IFN-inducible protein-10, lymphotactin, and IL-1R antagonist, as well as altered levels of chemokine receptors. We correlated gene expression with the physiologic process of allograft rejection using self-organizing maps and identified distinct patterns of gene expression in allografts from TNF-R1−/− recipients. These findings indicate that in our experimental system TNF-α and LTα exert profound immunoregulatory effects through TNF-R1.
Requirement for NK Cells in CD40 Ligand-Mediated Rejection of Philadelphia Chromosome-Positive Acute Lymphoblastic Leukemia Cells
Authors: Gruber Tanja A. , Skelton Dianne C. , Kohn Donald B. 
Published: April 2014

Abstract
We have previously developed a murine model of Philadelphia chromosome-positive acute lymphoblastic leukemia by i.v. injection of a pre-B ALL cell line (BM185) derived from Bcr-Abl-transformed BALB/c bone marrow. We are studying the potential to elicit autologous antileukemic immune responses by introducing genes encoding immunomodulators (CD40 ligand (CD40L), CD80, and GM-CSF) into leukemia cells. BM185 cells expressing CD40L or CD80 alone, when injected into BALB/c mice, were rejected in approximately 25% of mice, whereas cohorts receiving BM185 cells expressing two or more immunomodulator genes rejected challenge 50–76% of the time. The greatest protection was conferred in mice receiving BM185 cells expressing all three immunomodulators. Addition of murine rIL-12 treatments in conjunction with BM185/CD80/CD40L/GM-CSF vaccination allowed rejection of preestablished leukemia. BM185 cell lines expressing CD40L were rejected in BALB/c nu/nu (nude) mice, in contrast to cell lines expressing CD80 and/or GM-CSF. Nude mice depleted of NK cells were no longer protected when challenged with BM185/CD40L, demonstrating a requirement for NK cells. Similarly, NK cell depletion in immunocompetent BALB/c mice resulted in a loss of protection when challenged with BM185/CD40L, confirming the data seen in nude mice. The ability of CD40L to act in a T cell-independent manner may be important for clinical applications in patients with depressed cellular immunity following chemotherapy.
Impaired Development of T Lymphoid Precursors from Pluripotent Hematopoietic Stem Cells in New Zealand Black Mice
Authors: Hashimoto Yoshiko , Montecino-Rodriguez Encarnacion , Gershwin M. Eric , Dorshkind Kenneth 
Published: April 2014

Abstract
Bone marrow cells from autoimmune-prone New Zealand Black (NZB) mice are less efficient at colonizing fetal thymic lobes than cells from normal strains. This study demonstrates that the reduced capacity of NZB bone marrow cells to repopulate the thymus does not result from their inability to migrate to or enter the thymus. Rather, the T lymphopoietic defect of NZB mice is due to an impaired ability of pluripotent hematopoietic stem cells (PHSCs) to generate more committed lymphoid progeny, which could include common lymphoid precursors and/or other T cell-committed progenitors. Although PHSCs from NZB mice were not as efficient at thymic repopulation as comparable numbers of PHSCs from control strains, the ability of common lymphoid precursors from NZB mice to repopulate the thymus was not defective. Similarly, more differentiated NZB T cell precursors included in the intrathymic pool of CD4−CD8− cells also exhibited normal T lymphopoietic potential. Taken together, the results identify an unappreciated defect in NZB mice and provide further evidence that generation of lymphoid progeny from the PHSCs is a regulated event.
Human Anergic CD4+ T Cells Can Act as Suppressor Cells by Affecting Autologous Dendritic Cell Conditioning and Survival
Authors: Frasca Loredana , Scottà Cristiano , Lombardi Giovanna , Piccolella Enza 
Published: April 2014

AbstractT cell suppression exerted by regulatory T cells represents a well-established phenomenon, but the mechanisms involved are still a matter of debate. Recent data suggest that anergic T cells can suppress responder T cell activation by inhibiting Ag presentation by dendritic cells (DC). In this study, we focused our attention on the mechanisms that regulate the susceptibility of DC to suppressive signals and analyzed the fate of DC and responder T cells. To address this issue, we have cocultured human alloreactive or Ag-specific CD4+ T cell clones, rendered anergic by incubation with immobilized anti-CD3 Ab, with autologous DC and responder T cells. We show that anergic T cells affect either Ag-presenting functions or survival of DC, depending whether immature or mature DC are used as APC. Indeed, MHC and costimulatory molecule expression on immature DC activated by responder T cells is inhibited, while apoptotic programs are induced in mature DC and in turn in responder T cells. Ligation of CD95 by CD95L expressed on anergic T cells in the absence of CD40-CD40L (CD154) interaction are critical parameters in eliciting apoptosis in both DC and responder T cells. In conclusion, these findings indicate that the defective activation of CD40 on DC by CD95L+ CD154-defective anergic T cells could be the primary event in determining T cell suppression and support the role of CD40 signaling in regulating both conditioning and survival of DC.
CD2 Facilitates Differentiation of CD4 Th Cells Without Affecting Th1/Th2 Polarization
Authors: Sasada Tetsuro , Yang Hailin , Reinherz Ellis L. 
Published: April 2014

AbstractThe role of CD2 in murine CD4 helper T cell differentiation and polarization was examined using TCR-Cyt-5CC7-I transgenic recombination activating gene-2−/− H-2a mice on CD2+/+ or CD2−/− backgrounds. In the absence of CD2, thymic development was abnormal as judged by reduction in the steady state number of total, double-positive, and CD4 single-positive (SP) thymocytes, as well as a defect in their restorative dynamics after peptide-induced negative selection in vivo. In addition, in CD2−/− animals, lymph node CD4 SP T cells manifest a 10- to 100-fold attenuated activation response to cytochrome c (CytC) agonist peptides as judged by induction of CD25 and CD69 cell surface expression or [3H]TdR incorporation; differences in the magnitude of responsiveness and requisite molar peptide concentrations were even greater for altered peptide ligands. Although the presence or absence of CD2 did not impact the final Th1 or Th2 polarization outcome, CD2 expression reduced the CytC peptide concentration threshold necessary to facilitate both Th1 and Th2 differentiation. In vivo administration of CytC peptide to CD2−/− animals yielded an impaired CD4 SP T cell effector/memory phenotype compared with similarly treated CD2+/+ mice. Analysis of TCR-Cyt-5CC7-I human CD2 double-transgenic mice similarly failed to reveal a preferential Th1 vs Th2 polarization. Collectively, these results indicate that CD2 is important for the efficient development of CD4 SP thymocytes and TCR-dependent activation of mature CD4 lymph node T cells, but does not direct a particular helper T cell subset polarity.
Viral IFN-Regulatory Factors Inhibit Activation-Induced Cell Death Via Two Positive Regulatory IFN-Regulatory Factor 1-Dependent Domains in the CD95 Ligand Promoter
Authors: Kirchhoff Sabine , Sebens Thorsten , Baumann Sven , Krueger Andreas , Zawatzky Rainer , Li-Weber Min , Meinl Edgar , Neipel Frank , Fleckenstein Bernhard , Krammer Peter H. 
Published: April 2014

Abstract
The CD95 (also called APO-1/Fas) system plays a major role in the induction of apoptosis in lymphoid and nonlymphoid tissues. The CD95 ligand (CD95L) is induced in response to a variety of signals, including IFN-γ and TCR/CD3 stimulation. Here we report the identification of two positive regulatory IFN-regulatory factor-dependent domains (PRIDDs) in the CD95L promoter and its 5′ untranslated region, respectively. EMSAs demonstrate specific binding of IFN-γ-induced IFN-regulatory factor 1 (IRF-1) to the PRIDD sequences. Ectopic IRF-1 expression induces CD95L promoter activity. Furthermore, we demonstrate that PRIDDs play an important role in TCR/CD3-mediated CD95L induction. Most interestingly, viral IRFs of human herpes virus 8 (HHV8) totally abolish IRF-1-mediated and strongly reduce TCR/CD3-mediated CD95L induction. We demonstrate here for the first time that viral IRFs inhibit activation-induced cell death. Thus, these results demonstrate an important mechanism of HHV8 to modulate the immune response by down-regulation of CD95L expression. Inhibition of CD95-dependent T cell function might contribute to the immune escape of HHV8.
FcαRI/CD89 Circulates in Human Serum Covalently Linked to IgA in a Polymeric State
Authors: van der Boog Paul J. M. , van Zandbergen Ger , de Fijter Johan W. , Klar-Mohamad Ngaisah , van Seggelen Anneke , Brandtzaeg Per , Daha Mohamed R. , van Kooten Cees 
Published: April 2014

AbstractThe FcR for IgA CD89/FcαRI, is a type I receptor glycoprotein, expressed on myeloid cells, with important immune effector functions. In vitro CD89 can be released from CD89-expressing cells upon activation. Little information is available on the existence of this soluble molecule in vivo. Using specific and sensitive ELISA techniques (detection limit 50 pg/ml), we were not able to detect circulating CD89 in human sera. However, using Western blotting, a 30-kDa soluble CD89 molecule was demonstrated in both serum and plasma. Moreover, using a specific semiquantitative dot-blot system, we found CD89 in all human sera tested (mean concentration 1900 ng/ml). Size fractionation of human serum using gel filtration chromatography showed that the CD89 molecule was predominantly present in larger molecular mass fractions. Direct complexes between IgA and CD89 were demonstrated by anti-IgA affinity purification, and when analyzed under nonreducing conditions appeared to be covalently linked. Size fractionation of affinity-purified IgA showed the presence of soluble CD89 only in the high molecular mass fractions of IgA, but not in monomeric IgA. High molecular mass complexes of CD89-IgA could be distinguished from J chain containing dimeric IgA. These data show that CD89 circulates in complex with IgA, and suggest that CD89 might contribute to the formation of polymeric serum IgA.
CD40 Ligand-Deficient T Cells from X-Linked Hyper-IgM Syndrome Carriers Have Intrinsic Priming Capability
Authors: Lobo Francis M. , Scholl Paul R. , Fuleihan Ramsay L. 
Published: April 2014

Abstract
Deficiency in CD40 ligand (CD40L) expression is associated with impaired T cell immunity in mouse models and in humans. Previous studies have indicated that this is due to the failure of induction of extrinsic costimulatory molecules. However, other studies have suggested that CD40L is an intrinsic costimulatory molecule. The X-linked hyper-IgM syndrome (XHIM) is a primary immunodeficiency caused by mutations in CD40L, resulting in impaired Ab production and T cell immunity. CD4+ T cells from female carriers of XHIM express a variable degree of normal CD40L based on random X chromosome inactivation. We have examined T cells from XHIM carriers to investigate whether CD40L supports T cell function by acting as an intrinsic costimulator or by induction of other costimulatory molecules by examining coexpression of CD40L and markers of T lymphocyte priming. These carriers provide a unique model for comparison of CD40L-expressing and -nonexpressing lymphocytes in that all factors, including immunological experience, are equivalent between the two populations. Our results show that compared with CD40L-deficient T cells, T cells that express CD40L normally have a minimal advantage in becoming primed, as defined by CD45 RO isoform expression and production of IFN-γ and TNF-α. Conversely, CD40L-deficient T lymphocytes clearly were capable of becoming primed as defined by the same parameters. These findings imply that the intrinsic costimulatory activity of CD40L is not required for attaining primed status, and that CD40L primarily supports T cell function by inducing extrinsic factors that can be shared by CD40L-deficient cells.