bluuebunny/crossref_metadata_2025_split huggingface dataset:
Genetic Mapping of Two Murine Loci that Influence the Development of IL-4-Producing Thy-1dull γδ Thymocytes
Authors: Azuara Véronique , Pereira Pablo 
Published: April 2014

Abstract
IL-4-producing γδ cells belong to a novel subset of γδ lymphocytes that expresses a very restricted repertoire of TCRs. To gain a deeper insight into the development and in vivo functions of these cells, we have analyzed the genetic control of their representation in the thymus. Using an intercross between C57BL/6 and DBA/2 mice we found two loci on chromosomes 13 and 17—named LadT1 and LadT2, respectively—with marked influence in their development. The LadT2 locus does not appear to be the MHC locus. The region identified on mouse chromosome 13 contains the structural genes for TCRγ as well as the IL-9 gene, which has been suggested as a candidate gene influencing the complex pathogenesis of asthma.
Divergent Effects of Platelet-Endothelial Cell Adhesion Molecule-1 and β3 Integrin Blockade on Leukocyte Transmigration In Vivo
Authors: Thompson Richard D. , Wakelin Matthew W. , Larbi Karen Y. , Dewar Ann , Asimakopoulos George , Horton Michael A. , Nakada Marian T. , Nourshargh Sussan 
Published: April 2014

AbstractThe final stage in the migration of leukocytes to sites of inflammation involves movement of leukocytes through the endothelial cell layer and the perivascular basement membrane. Both platelet-endothelial cell adhesion molecule-1 (PECAM-1/CD31) and the integrin αvβ3 have been implicated in this process, and in vitro studies have identified αvβ3 as a heterotypic ligand for PECAM-1. In the present study we have addressed the roles of these molecules by investigating and comparing the effects of PECAM-1 and αvβ3 blockade on leukocyte migration in vivo. For this purpose we have examined the effects of neutralizing Abs directed against PECAM-1 (domain 1-specific, mAb 37) and β3 integrins (mAbs 7E3 and F11) on leukocyte responses in the mesenteric microcirculation of anesthetized rats using intravital microscopy. The anti-PECAM-1 mAb suppressed leukocyte extravasation, but not leukocyte rolling or firm adhesion, elicited by IL-1β in a dose-dependent manner (e.g., 67% inhibition at 10 mg/kg 37 Fab), but had no effect on FMLP-induced leukocyte responses. Analysis by electron microscopy suggested that this suppression was due to an inhibition of neutrophil migration through the endothelial cell barrier. By contrast, both anti-β3 integrin mAbs, 7E3 F(ab′)2 (5 mg/kg) and F11 F(ab′)2 (5 mg/kg), selectively reduced leukocyte extravasation induced by FMLP (38 and 46%, respectively), but neither mAb had an effect on IL-1β-induced leukocyte responses. These findings indicate roles for both PECAM-1 and β3 integrins in leukocyte extravasation, but do not support the concept that these molecules act as counter-receptors in mediating leukocyte transmigration.
Lethal Granuloma Disintegration in Mycobacteria-Infected TNFRp55−/− Mice Is Dependent on T Cells and IL-12
Authors: Ehlers Stefan , Kutsch Stefanie , Ehlers Eva M. , Benini Jochen , Pfeffer Klaus 
Published: April 2014

AbstractGenetically susceptible, TNFRp55 gene-deficient (TNFRp55−/−) mice succumb to infection with Mycobacterium avium. Before their death, M. avium-infected TNFRp55−/− mice develop granulomatous lesions that, in contrast to granulomas in wild-type syngeneic mice, undergo acute disintegration. To determine the factors involved in these events, we depleted T cell subsets or neutralized the inflammatory cytokines IFN-γ, IL-12, or TNF in TNFRp55−/− mice infected i.v. with M. avium. Infected TNFRp55−/− mice treated with a control mAb became moribund between days 26 and 34 postinfection, showing widespread inflammatory cell apoptosis within disintegrating granulomas. In contrast, TNFRp55−/− mice depleted of either CD4+ or CD8+ cells after granuloma initiation stayed healthy until at least day 38 postinfection and showed no signs of granuloma destruction. Neutralization of IL-12, but not of IFN-γ or TNF, also protected M. avium-infected TNFRp55−/− mice from granuloma decomposition and from premature death. Treatment with dexamethasone or with a specific inhibitor of inducible NO synthase did not prevent granuloma dissolution or death of TNFRp55−/− mice. In conclusion, granuloma disintegration in TNFRp55−/− mice is a lethal event that is dependent on IL-12 and that is mediated by an excess of T cells.
Cutting Edge: Antilisterial Activity of CD8+ T Cells Derived from TNF-Deficient and TNF/Perforin Double-Deficient Mice
Authors: White Douglas W. , Badovinac Vladimir P. , Kollias George , Harty John T. 
Published: April 2014

AbstractThe mechanisms by which CD8+ T cells mediate immunity against bacterial pathogens remain largely unknown. Perforin-dependent cytolysis plays a role, but is not required for CD8+ T cell-mediated immunity against Listeria monocytogenes. TNF is essential for CD8+ T cell immunity to L. monocytogenes, but the cellular source of TNF is undefined. TNF-deficient and TNF/perforin double-deficient mice were used to generate CD8+ T cells specific for an L. monocytogenes-derived Ag. Wild-type and TNF-deficient CD8+ T cells mediated antilisterial immunity in wild-type but not TNF-deficient host mice, revealing that CD8+ T cell-derived TNF is not required for CD8+ T cell-mediated antilisterial immunity, but demonstrating a role for TNF derived from other cell types. TNF/perforin double-deficient CD8+ T cells mediated antilisterial immunity in the liver, but not in the spleen, of wild-type recipient mice, suggesting that perforin-independent immunity in the spleen requires CD8+ T cell-derived TNF.
Regulation of Human Cell Engraftment and Development of EBV-Related Lymphoproliferative Disorders in Hu-PBL-scidMice
Authors: Wagar Eric J. , Cromwell Mandy A. , Shultz Leonard D. , Woda Bruce A. , Sullivan John L. , Hesselton RuthAnn M. , Greiner Dale L. 
Published: April 2014

AbstractHuman PBMC engraft in mice homozygous for the severe combined immunodeficiency (Prkdcscid) mutation (Hu-PBL-scid mice). Hu-PBL-NOD-scid mice generate 5- to 10-fold higher levels of human cells than do Hu-PBL-C.B-17-scid mice, and Hu-PBL-NOD-scid β2-microglobulin-null (NOD-scid-B2mnull) mice support even higher levels of engraftment, particularly CD4+ T cells. The basis for increased engraftment of human PBMC and the functional capabilities of these cells in NOD-scid and NOD-scid-B2mnull mice are unknown. We now report that human cell proliferation in NOD-scid mice increased after in vivo depletion of NK cells. Human cell engraftment depended on CD4+ cells and required CD40-CD154 interaction, but engrafted CD4+ cells rapidly became nonresponsive to anti-CD3 Ab stimulation. Depletion of human CD8+ cells led to increased human CD4+ and CD20+ cell engraftment and increased levels of human Ig. We further document that Hu-PBL-NOD-scid mice are resistant to development of human EBV-related lymphoproliferative disorders. These disorders, however, develop rapidly following depletion of human CD8+ cells and are prevented by re-engraftment of CD8+ T cells. These data demonstrate that 1) murine NK cells regulate human cell engraftment in scid recipients; 2) human CD4+ cells are required for human CD8+ cell engraftment; and 3) once engrafted, human CD8+ cells regulate human CD4+ and CD20+ cell expansion, Ig levels, and outgrowth of EBV-related lymphoproliferative disorders. We propose that the Hu-PBL-NOD-scid model is suitable for the in vivo analysis of immunoregulatory interactions between human CD4+ and CD8+ cells.
Functional Reconstitution of Class II MHC-Restricted T Cell Immunity Mediated by Retroviral Transfer of the αβ TCR Complex
Authors: Fujio Keishi , Misaki Yoshikata , Setoguchi Keigo , Morita Sumiyo , Kawahata Kimito , Kato Ikunoshin , Nosaka Tetsuya , Yamamoto Kazuhiko , Kitamura Toshio 
Published: April 2014

AbstractTransfer of the αβ TCR genes into T lymphocytes will provide a means to enhance Ag-specific immunity by increasing the frequency of tumor- or pathogen-specific T lymphocytes. We generated an efficient αβ TCR gene transfer system using two independent monocistronic retrovirus vectors harboring either of the class II MHC-restricted α or β TCR genes specific for chicken OVA. The system enabled us to express the clonotypic TCR in 44% of the CD4+ T cells. The transduced cells showed a remarkable response to OVA323–339 peptide in the in vitro culture system, and the response to the Ag was comparable with those of the T lymphocytes derived from transgenic mice harboring OVA-specific TCR. Adoptive transfer of the TCR-transduced cells in mice induced the Ag-specific delayed-type hypersensitivity in response to OVA323–339 challenge. These results indicate that αβ TCR gene transfer into peripheral T lymphocytes can reconstitute Ag-specific immunity. We here propose that this method provides a basis for a new approach to manipulation of immune reactions and immunotherapy.
Heparan Sulfate-Like Proteoglycans Mediate Adhesion of Human Malignant Melanoma A375 Cells to P-Selectin Under Flow
Authors: Ma Yan-Qing , Geng Jian-Guo 
Published: April 2014

AbstractSelectins, a family of cell adhesion molecules, bind to sialylated and fucosylated carbohydrates, such as sialyl Lewisx (SLex) and its derivatives, as their minimal recognition motif. Here we report that P-selectin bound to human malignant melanoma A375 cells and mediated their adhesion under flow. However, probing with a specific Ab failed to detect any apparent expression of SLex. This finding was bolstered by reduced expression of α-1,3-fucosyltransferase VII mRNA and by absence of the cell surface expression of P-selectin glycoprotein ligand-1. Instead, they expressed heparan sulfate-like proteoglycans on their cell surfaces. Treatment with β-d-xyloside (a proteoglycan biosynthesis inhibitor) or heparinases could reduce the binding of these cells to P-selectin. In the competition assays, heparin, but not other proteoglycans, could abolish the P-selectin recognition. Further, we found that P-selectin could bind specifically to human tongue squamous cancer Tca-8113 cells, which had negative staining of SLex but positive staining of heparan sulfates. Both β-d-xyloside and heparinases could reduce the binding of P-selectin to Tca-8113 cells. Our results thus indicate that heparan sulfate-like proteoglycans can mediate adhesion of certain types of non-blood borne, “epithelial-like” human cancer cells to P-selectin.
Clonal Expansion of Infiltrating T Cells in the Spinal Cords of SJL/J Mice Infected with Theiler’s Virus
Authors: Kang Jeong-Ah , Mohindru Mani , Kang Bong-Su , Park Seol Hee , Kim Byung S. 
Published: April 2014

AbstractIntracerebral infection of susceptible mice with Theiler’s murine encephalomyelitis virus results in immune-mediated inflammatory demyelination in the white matter and consequent clinical symptoms. This system has been utilized as an important virus model for human multiple sclerosis. Although the potential involvement of virus-specific Th cells has been studied extensively, very little is known about the nature of T cells infiltrating the CNS during viral infection and their role in the development of demyelinating disease. In this study, the clonal nature of T cells in the spinal cord during the disease course was analyzed using size spectratyping and sequencing of the TCR β-chain CDR3 region. These studies clearly indicate that T cells are clonally expanded in the CNS after viral infection, although the overall TCR repertoire appears to be diverse. The clonal expansion appears to be Ag-driven in that it includes Th cells specific for known viral epitopes. Interestingly, such restricted accumulation of T cells was not detectable in the infiltrates of mice with proteolipid protein peptide-induced experimental autoimmune encephalomyelitis. The initial T cell repertoire (7–9 days postinfection) seems to be more diverse than that observed in the later stage (65 days) of virally induced demyelination, despite the more restricted utilization of Vβ subfamilies. These results strongly suggest continuous stimulation and clonal expansion of virus-specific T cells in the CNS of Theiler’s murine encephalomyelitis virus-infected mice during the entire course of demyelinating disease.
Subtle Effects on Myelin Basic Protein-Specific T Cell Responses Can Lead to a Major Reduction in Disease Susceptibility in Experimental Allergic Encephalomyelitis
Authors: Vowles Cheryl , Chan Vera S. F. , Bodmer Helen C. 
Published: April 2014

AbstractThe presence of potentially autoreactive T cells is a necessary, but not sufficient, condition for the development of autoimmune disease. However, the relationship between T cell response and susceptibility to disease is not straightforward. In this report, we use experimental allergic encephalomyelitis as a model to demonstrate that subtle alterations of the T cell response to an encephalitogenic epitope are sufficient to cause a dramatic decrease in disease susceptibility. Transgenic expression of a fusion protein of hen egg lysozyme and an encephalitogenic peptide of myelin basic protein (MBP) residues 84–105, coexpressed with MHC class II, causes profound tolerance to hen egg lysozyme, while maintaining a near normal response to MBP. Detailed analysis of the T cell repertoire of transgenic animals using a panel of T cell hybridomas revealed a highly selective loss of one minor component of the response to the MBP84–104 region. Despite this, transgenic animals were highly resistant to experimental allergic encephalomyelitis induction with the MBP peptide, indicating that minor changes to the T cell repertoire may result in major alterations in disease susceptibility. Possible reasons for this are discussed.
Differential Role of p38 and c-Jun N-Terminal Kinase 1 Mitogen-Activated Protein Kinases in NK Cell Cytotoxicity
Authors: Trotta Rossana , Fettucciari Katia , Azzoni Livio , Abebe Bekele , Puorro Kristin A. , Eisenlohr Laurence C. , Perussia Bice 
Published: April 2014

AbstractThe serine-threonine mitogen-activated protein kinase (MAPK) family includes extracellular signal-regulated kinases (ERK), c-Jun N-terminal kinases (JNK), and p38 kinases. In NK cells, spontaneous or Ab-mediated recognition of target cells leads to activation of an ERK-2 MAPK-dependent biochemical pathway(s) involved in the regulation of NK cell effector functions. Here we assessed the roles of p38 and JNK MAPK in NK cell-mediated cytotoxicity. Our data indicate that p38 is activated in primary human NK cells upon stimulation with immune complexes and interaction with NK-sensitive target cells. FcγRIIIA-induced granule exocytosis and both spontaneous and Ab-dependent cytotoxicity were reduced in a dose-dependent manner in cells pretreated with either of two specific inhibitors of this kinase. Target cell-induced IFN-γ and FcγRIIIA-induced TNF-α mRNA accumulation was similarly affected under the same conditions. Lack of inhibition of NK cell cytotoxicity in cells overexpressing an inactive form of JNK1 indicates that this kinase, activated only upon FcγRIIIA ligation, does not play a significant role in cytotoxicity. These data underscore the involvement of p38, but not JNK1, in the molecular mechanisms regulating NK cell cytotoxicity.
Response of Murine γδ T Cells to the Synthetic Polypeptide Poly-Glu50Tyr50 1
Authors: Cady Carol T. , Lahn Michael , Vollmer Michaelann , Tsuji Moriya , Seo Seong Jun , Reardon Christopher L. , O’Brien Rebecca L. , Born Willi K. 
Published: April 2014

Abstract
Random heterocopolymers of glutamic acid and tyrosine (pEY) evoke strong, genetically controlled immune responses in certain mouse strains. We found that pE50Y50 also stimulated polyclonal proliferation of normal γδ, but not αβ, T cells. Proliferation of γδ T cells did not require prior immunization with this Ag nor the presence of αβ T cells, but was enhanced by IL-2. The γδ T cell response proceeded in the absence of accessory cells, MHC class II, β2-microglobulin, or TAP-1, suggesting that Ag presentation by MHC class I/II molecules and peptide processing are not required. Among normal splenocytes, as with γδ T cell hybridomas, the response was strongest with Vγ1+ γδ T cells, and in comparison with related polypeptides, pE50Y50 provided the strongest stimulus for these cells. TCR gene transfer into a TCR-deficient αβ T cell showed that besides the TCR, no other components unique to γδ T cells are needed. Furthermore, interactions between only the T cells and pE50Y50 were sufficient to bring about the response. Thus, pE50Y50 elicited a response distinct from those of T cells to processed/presented peptides or superantigens, consistent with a mechanism of Ig-like ligand recognition of γδ T cells. Direct stimulation by ligands resembling pE50Y50 may thus selectively evoke contributions of γδ T cells to the host response.
Distinct Molecular Mechanisms of Fas Resistance in Murine B Lymphoma Cells
Authors: Mueller Carolyn M. , Scott David W. 
Published: April 2014

Abstract
A panel of murine B lymphoma cell lines, which express different levels of Fas, was extensively studied for sensitivity to Fas-mediated death signals via an anti-Fas mAb and Fas ligand-bearing cell lines. Expression of the Fas receptor on the B lymphoma cell lines did not correlate with their capacity to undergo Fas-mediated apoptosis. Moreover, Fas-associated death domain protein recruitment to the death-inducing signaling complex (DISC) complex occurred in all cell lines expressing Fas, regardless of whether they were sensitive to Fas-mediated death. Interestingly, the protein synthesis inhibitor, cycloheximide, and protein kinase C inhibitors, such as bisindolylmaleimide, rendered one of the resistant cell lines, CH33, sensitive to signals from the Fas receptor, although the levels of Fas were unchanged. This suggests that constitutive PKC activation plays a role in Fas resistance, perhaps by up-regulating NF-κB or Bcl-2 family members. Interestingly, CH33 demonstrated caspase 8 activity upon engagement of the Fas receptor in the absence of pharmacological manipulation, suggesting that the block in apoptosis is downstream of the DISC complex. In contrast, the fact that Fas-associated death domain protein was recruited to the DISC complex in other resistant lines, such as WEHI-231, with no caspase 8 activation indicates that these cells may be blocked within the DISC complex. Indeed, Western blot analysis showed that WEHI-231 expressed an isoform of FLICE-like inhibitory protein (cFLIPL), an antiapoptotic protein within the DISC. These studies provide evidence that murine B lymphoma cells utilize different molecular mechanisms along the Fas-signaling cascade to block apoptosis.
Opening a Window on Thymic Positive Selection: Developmental Changes in the Influence of Cosignaling by Integrins and CD28 on Selection Events Induced by TCR Engagement
Authors: Lucas Bruno , Germain Ronald N. 
Published: April 2014

AbstractHow TCR and non-TCR signals are integrated by thymocytes to generate a decision to undergo either positive or negative selection remains incompletely understood. Recent evidence suggests that TCR signal transduction changes its quality during thymocyte maturation, but whether the contributions of various cosignaling or costimulatory pathways to thymocyte selection also are modified during development is unclear. Questions also remain about the possible selective roles of specific costimulatory pathways in induction of differentiation vs death among thymocytes at any given stage of maturity. To address these issues, a quantitative in vitro analysis of initiation of CD4+CD8+ thymocyte differentiation as measured by CD69 up-regulation/coreceptor down-modulation was conducted in parallel with an analysis of induction of death. Using transfected cells varying in their surface display of ICAM-1 or B7.1 along with antibody blocking experiments, we demonstrate here that ICAM-1 provides a selective boost to signaling for differentiation without substantially affecting induction of death among CD4+CD8+ cells, a property that is lost as thymocytes mature further. In contrast, B7 engagement enhances both cell activation and death in parallel. Based on these data, we propose that the high level of ICAM-1 on cortical epithelial cells plays a special role in opening a window between TCR signaling for differentiation vs death, permitting efficient initiation of positive selection on epithelial ligands. In contrast, late CD28-dependent cosignaling on hemopoietic cells in the medulla would help enforce negative selection by augmenting the effects of TCR engagement by low levels of high affinity ligands.
αβTCR+ Cells Are a Minimal Fraction of Peripheral CD8+ Pool in MHC Class I-Deficient Mice
Authors: Nešić Dragana , Santori Fabio R. , Vukmanović Stanislav 
Published: April 2014

AbstractMHC class I molecules play a role in the maintenance of the naive peripheral CD8+ T cell pool. The mechanisms of the peripheral maintenance and the life span of residual CD8+ cells present in the periphery of β2-microglobulin-deficient (β2m−/−) mice are unknown. We here show that very few CD8+ cells in β2m−/− mice coexpress CD8β, a marker of the thymus-derived CD8+ T cells. Most of the CD8α+ cells express CD11c and can be found in β2m/RAG-2 double-deficient mice, demonstrating that these cells do not require rearranged Ag receptors for differentiation and survival and may be of dendritic cell lineage. Rare CD8α+CD8β+ cells can be detected following in vivo alloantigenic stimulation 2 wk after the adult thymectomy. Selective MHC class I expression by bone marrow-derived cells does not lead to an accumulation of CD8β+ cells in β2m−/− mice. These findings demonstrate that 1) thymic export of CD8+ T cells in β2m−/− mice is reduced more severely than previously thought; 2) non-T cells expressing CD8α become prominent when CD8+ T cells are virtually absent; 3) at least some β2m−/− CD8+ T cells have a life span in the periphery comparable to wild-type CD8+ cells; and 4) similar ligands induce positive selection in the thymus and survival of CD8+ T cells in the periphery.
Cytolytic Mechanisms and Expression of Activation-Regulating Receptors on Effector-Type CD8+CD45RA+CD27− Human T Cells
Authors: Baars Paul A. , Ribeiro do Couto Laura M. , Leusen Jeanette H. W. , Hooibrink Berend , Kuijpers Taco W. , Lens Susanne M. A. , van Lier René A. W. 
Published: April 2014

Abstract
Circulating CD8+ T cells with a CD45RA+CD27− phenotype resemble cytolytic effector cells because they express various cytolytic mediators and are able to execute cytotoxicity without prior stimulation in vitro. We here demonstrate that CD8+CD45RA+CD27− T cells can use both granule exocytosis and Fas/Fas ligand pathways to induce apoptosis in target cells. The availability of these cytolytic mechanisms in circulating T cells suggests that the activity of these cells must be carefully controlled to prevent unwanted tissue damage. For this reason, we analyzed the expression of surface receptors that either enhance or inhibit T cell function. Compared with memory-type cells, effector cells were found to express normal levels of CD3ε and TCRζ and relatively high levels of CD8. CTLA-4 was absent from freshly isolated effector cells, whereas a limited number of unstimulated memory cells expressed this molecule. In line with recent findings on CD8+CD28− T cells, CD45RA+CD27− T cells were unique in the abundant expression of NK cell-inhibitory receptors, both of Ig superfamily and C-type lectin classes. Binding of NK cell-inhibitory receptors to classical and nonclassical MHC class I molecules may inhibit the activation of the cytolytic machinery induced by either Ag receptor-specific or nonspecific signals in CD8+CD45RA+CD27− T cells.