bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Role for Oxidative Stress in Apoptosis: Oxidation and Externalization of Phosphatidylserine Is Required for Macrophage Clearance of Cells Undergoing Fas-Mediated Apoptosis
Authors: Kagan Valerian E. , Gleiss Bettina , Tyurina Yulia Y. , Tyurin Vladimir A. , Elenström-Magnusson Carina , Liu Shang-Xi , Serinkan F. Behice , Arroyo Antonio , Chandra Joya , Orrenius Sten , Fadeel Bengt 
Published: April 2014

Abstract
Exposure of phosphatidylserine (PS) on the surface of apoptotic cells has been suggested to serve as an important recognition signal for macrophages. In this work we show that triggering of the death receptor Fas on Jurkat cells results in the generation of reactive oxygen species with oxidation and externalization of PS but not of the other major aminophospholipid, phosphatidylethanolamine. These cells were readily ingested by several classes of macrophages, whereas Raji cells, which are defective for Fas-induced PS exposure, remained unengulfed. However, when Raji cells were incubated with the thiol-reactive agent N-ethylmaleimide to induce PS exposure in the absence of other features of apoptosis, these cells were also engulfed by macrophages. Phagocytosis of Fas-triggered Jurkat cells was inhibited by superoxide dismutase and catalase, which prevent oxidation of PS while allowing PS to remain externalized on these cells. Moreover, liposomes containing oxidized PS (PS-OX) were more potent inhibitors of phagocytosis than those containing its nonoxidized counterpart. Finally, enrichment of the plasma membrane of Jurkat or Raji cells, or myeloid leukemic HL-60 cells, with exogenous PS resulted in phagocytic cell clearance, and this process was further enhanced when PS was substituted for by PS-OX. Taken together, our data suggest that the presence of PS-OX in conjunction with nonoxidized PS on the cell surface is an important signal for macrophage clearance of apoptotic cells.
Generation of CTL Recognizing an HLA-A*0201-Restricted Epitope Shared by MAGE-A1, -A2, -A3, -A4, -A6, -A10, and -A12 Tumor Antigens: Implication in a Broad-Spectrum Tumor Immunotherapy
Authors: Graff-Dubois Stéphanie , Faure Olivier , Gross David-Alexandre , Alves Pedro , Scardino Antonio , Chouaib Salem , Lemonnier François A. , Kosmatopoulos Kostas 
Published: April 2014

Abstract
MAGE-A1, -A2, -A3, -A4, -A6, -A10, and -A12 are expressed in a significant proportion of primary and metastatic tumors of various histological types and are targets of tumor Ag-specific CTL. Individual MAGE-A expression varies from one tumor type to the other but, overall, the large majority of tumors expresses at least one MAGE-A Ag. Therefore, targeting epitopes shared by all MAGE-A Ags would be of interest in immunotherapy against a broad spectrum of cancers. In the present study, we describe a heteroclitic MAGE-A peptide (p248V9) that induces CTL in vivo in HLA-A*0201 transgenic HHD mice and in vitro in healthy donors. These CTL are able to recognize two low HLA-A*0201 affinity peptides differing at their C-terminal position and derived from MAGE-A2, -A3, -A4, -A6, -A10, and -A12 (p248G9) and MAGE-A1 (p248D9). Interestingly, p248V9-specific CTL respond to endogenous MAGE-A1, -A2, -A3, -A4, -A6, -A10, and -A12 in an HLA-A*0201-restricted manner and recognize human HLA-A*0201+MAGE-A+ tumor cells of various histological origin. Therefore, this heteroclitic peptide may be considered as a potent candidate for a broad-spectrum tumor vaccination.
Aberrant Production of IL-12 by Macrophages from Several Autoimmune-Prone Mouse Strains Is Characterized by Intrinsic and Unique Patterns of NF-κB Expression and Binding to the IL-12 p40 Promoter
Authors: Liu Jiajian , Beller David 
Published: April 2014

Abstract
Intrinsic defects in macrophage (Mφ) cytokine production characterize many autoimmune-prone mouse strains. Aberrant levels of IL-12, for example, are produced by Mφ isolated from young mice prone to lupus (MRL and NZB/W) and diabetes (nonobese diabetic (NOD)) well before the appearance of disease signs. Evaluation of the possible mechanism(s) underlying the abnormal regulation of IL-12 in these strains revealed novel patterns of Rel family protein binding to the unique p40 NF-κB site in the IL-12 p40 promoter, whereas binding patterns to Ets and CCAAT enhancer binding protein/β sites were normal. In particular, the heightened production of IL-12 by NOD Mφ is associated with elevated levels of the trans-activating p50/c-Rel (p65) complex compared with the nonfunctional p50/p50 dimer. Conversely, the dramatically impaired production of IL-12 by both NZB/W and MRL/+ Mφ is associated with a predominance of p50/p50 and reduced p50/c-Rel(p65) binding. Mechanistically, the unique pattern seen in the lupus strains reflects elevated p50 and reduced c-Rel nuclear protein levels. In NOD extracts, the level of c-Rel is elevated compared with that in lupus strains, but not when compared with that in normal A/J. However, the extent of c-Rel tyrosine phosphorylation noted in NOD extracts is more than double that seen in any other strain. Levels of p65 were similar in all strains tested. These findings reveal that a common mechanism, involving dysregulation of c-Rel and p50, may be used to determine the aberrant IL-12 levels that have the potential to predispose specific mouse strains to systemic or organ-specific autoimmunity.
IL-12 Administration Leads to a Transient Depletion of T Cells, B Cells, and APCs and Concomitant Abrogation of the HLA-A2.1-Restricted CTL Response in Transgenic Mice
Authors: Peter Katrin , Brunda Michael J. , Corradin Giampietro 
Published: April 2014

Abstract
The injection of a mixture of bona fide T cell epitopes can lead to the occurrence of immunodominance, meaning that the immune response is focused on the recognition of a single epitope or a small portion of the epitopes injected. We have previously demonstrated that the administration of rIL-12 can counteract immunodominance in BALB/c mice. In this study, we show that the administration of rIL-12 to HLA-A2.1 transgenic mice (A2kb mice) abrogates specifically the immune response against HLA-A2.1-restricted HIV epitopes in the spleen. This lack of immune response is most probably due to a transient depletion of B cells, T cells, macrophages, and dendritic cells in this organ. Therefore, our study explains the mechanism of immunosuppression by rIL-12 in vivo.
Cutting Edge: Persistent Viral Infection Prevents Tolerance Induction and Escapes Immune Control Following CD28/CD40 Blockade-Based Regimen
Authors: Williams Matthew A. , Onami Thandi M. , Adams Andrew B. , Durham Megan M. , Pearson Thomas C. , Ahmed Rafi , Larsen Christian P. 
Published: April 2014

Abstract
A continuing concern with CD28 and/or CD40 blockade-based strategies to induce tolerance and mixed chimerism is their potential to disrupt protective immunity to preexisting infections. In this report, we find that preexisting persistent infection with lymphocytic choriomeningitis virus (LCMV) clone 13 prevents the induction of tolerance, mixed chimerism, and donor-reactive T cell deletion. Mice continue to be refractory to tolerance induction even after viremia has been resolved and virus is present only at very low levels in peripheral tissues. Conversely, we find that the full tolerance regimen, or costimulation blockade alone, specifically inhibits already ongoing antiviral immune responses, leading to an inability to control viremia. These findings suggest that ongoing T cell responses continue to depend on costimulatory interactions in the setting of a chronic infection and provide insight into potential risks following costimulation blockade posed by chronic or latent viral infections such as hepatitis C, EBV, and CMV.
Cutting Edge: CD4+CD25+ Alloantigen-Specific Immunoregulatory Cells That Can Prevent CD8+ T Cell-Mediated Graft Rejection: Implications for Anti-CD154 Immunotherapy
Authors: Maurik Andre van , Herber Manuela , Wood Kathryn J. , Jones Nick D. 
Published: April 2014

AbstractBlockade of CD40-CD154 interactions can facilitate long-term allograft acceptance in selected rodent and in primate models, but, due to the ability of CD154-independent CD8+ T cells to initiate graft rejection, this strategy is not always effective. In this work we demonstrate that blockade of the CD40-CD154 pathway at the time of transplantation enables the generation of donor alloantigen-specific CD4+CD25+ regulatory T cells, and that if the regulatory cells are present in sufficient numbers they can suppress allograft rejection mediated by CD154-independent CD8+ T cells.
Cutting Edge: Association of the Motor Protein Nonmuscle Myosin Heavy Chain-IIA with the C Terminus of the Chemokine Receptor CXCR4 in T Lymphocytes
Authors: Rey Mercedes , Vicente-Manzanares Miguel , Viedma Fernando , Yáñez-Mó María , Urzainqui Ana , Barreiro Olga , Vázquez Jesús , Sánchez-Madrid Francisco 
Published: April 2014

AbstractThe binding of chemokines to their receptors guides lymphocyte migration. However, the precise mechanism that links the chemotactic signals with the energy and traction force generated by the actomyosin complex of the cell has not been elucidated. Using biochemical approaches and mass spectrometry analysis, we found an association between the C-termini of CXCR4 and CCR5 and the motor protein nonmuscle myosin H chain-IIA. Immunoprecipitation experiments revealed that this association also occurs between the endogenous molecules in T lymphocytes. As expected, myosin L chain was also associated with CXCR4. Confocal microscopy analysis showed that CXCR4 and motor protein nonmuscle myosin H chain-IIA colocalize at the leading edge of migrating T lymphocytes, together with filamentous actin and myosin L chain. These results provide the first evidence of a biochemical association between chemokine receptors and motor proteins, a mechanosignaling mechanism that may have a key role in lymphocyte migration.
TRAIL/Apo-2 Ligand Induces Primary Plasma Cell Apoptosis
Authors: Ursini-Siegel Josie , Zhang Wenli , Altmeyer Anne , Hatada Eunice N. , Do Richard K. G. , Yagita Hideo , Chen-Kiang Selina 
Published: April 2014

AbstractApoptosis constitutes the primary mechanism by which noncycling plasma cells are eliminated after the secretion of Ag-specific Abs in a humoral immune response. The underlying mechanism is not known. Here, we demonstrate that the expression of both TRAIL/Apo-2 ligand and the death receptors (DR) DR5 and DR4, but not Fas, are sustained in IL-6-differentiated Ig-secreting human plasma cells as well as primary mouse plasma cells generated in a T-dependent immune response. Plasma cell apoptosis is induced by both endogenous and exogenous TRAIL ex vivo, suggesting that TRAIL-mediated killing may, in part, be plasma cell autonomous. By contrast, resting and activated B cells are resistant to TRAIL killing despite comparable expression of TRAIL and DRs. The preferential killing of plasma cells by TRAIL correlates with decreased expression of CD40 and inactivation of NF-κB. These results provide the first evidence that primary plasma cells synthesize TRAIL and are direct targets of TRAIL-mediated apoptosis, which may relate to the inactivation of the NF-κB survival pathway.
Injection of Soluble Antigen into the Anterior Chamber of the Eye Induces Expansion and Functional Unresponsiveness of Antigen-Specific CD8+ T Cells
Authors: McKenna Kyle C. , Xu Yijun , Kapp Judith A. 
Published: April 2014

AbstractThe injection of soluble Ag into the anterior chamber (a.c.) of the eye induces systemic tolerance, termed a.c.-associated immune deviation (ACAID), characterized by Ag-specific inhibition of delayed-type hypersensitivity responses and a reduction in complement-fixing Abs. Recently, we have shown that CD8+ CTL responses are also inhibited in ACAID. In this study, we have used an adoptive transfer approach to follow the fate of Ag-specific CD8+ TCR transgenic (OT-I) T cells in vivo during the induction and expression of ACAID. C57BL/6 (B6) recipients of OT-I splenocytes that were injected with chicken OVA in the a.c. displayed reduced OVA-specific delayed-type hypersensitivity and CTL responses, compared with those of mice given OVA in the subconjunctiva or an irrelevant Ag human IgG in the a.c. OT-I T cells increased 9-fold in the submandibular lymph nodes and 3-fold in the spleen following an a.c. injection with OVA, indicating that expansion rather than deletion of Ag-specific CD8+ T cells was induced by this treatment. OT-I T cells expanded equivalently upon administration of OVA in CFA to mice previously given OVA in the a.c. or subconjunctiva. However, the lytic activity attributed to OT-I T cells was reduced on a per-cell basis in mice previously given OVA in the a.c. We conclude that tolerance of CTL responses in mice given Ag via the a.c. results from unresponsiveness of Ag-specific CD8+ T cells.
Granulocyte-Macrophage Colony-Stimulating Factor (GM-CSF) and Inflammatory Stimuli Up-Regulate Secretion of the Soluble GM-CSF Receptor in Human Monocytes: Evidence for Ectodomain Shedding of the Cell Surface GM-CSF Receptor α Subunit
Authors: Prevost Jay M. , Pelley Jennifer L. , Zhu Weibin , D’Egidio Gianni E. , Beaudry Paul P. , Pihl Carin , Neely Graham G. , Claret Emmanuel , Wijdenes John , Brown Christopher B. 
Published: April 2014

AbstractSoluble GM-CSF receptor α subunit (sGMRα) is a soluble isoform of the GMRα that is believed to arise exclusively through alternative splicing of the GMRα gene product. The sGMRα mRNA is expressed in a variety of tissues, but it is not clear which cells are capable of secreting the protein. We show here that normal human monocytes, but not lymphocytes, constitutively secrete sGMRα. Stimulation of monocytes with GM-CSF, LPS, PMA, or A23187 rapidly up-regulates the secretion of sGMRα in a dose-dependent manner, demonstrating that secretion is also regulated. To determine whether sGMRα arose exclusively through alternative splicing of the GMRα gene product, or whether it could also be generated through ectodomain shedding of GMRα, we engineered a murine pro-B cell line (Ba/F3) to express exclusively the cDNA for cell surface GMRα (Ba/F3.GMRα). The Ba/F3.GMRα cell line, but not the parental Ba/F3 cell line, constitutively shed a sGMRα-like protein that bound specifically to GM-CSF, was equivalent in size to recombinant alternatively spliced sGMRα (60 kDa), and was recognized specifically by a mAb raised against the ectodomain of GMRα. Furthermore, a broad-spectrum metalloprotease inhibitor (BB94) reduced constitutive and PMA-, A23187-, and LPS-induced secretion of sGMRα by monocytes, suggesting that shedding of GMRα by monocytes may be mediated in part through the activity of metalloproteases. Taken together, these observations demonstrate that sGMRα is constitutively secreted by monocytes, that GM-CSF and inflammatory mediators up-regulate sGMRα secretion, and that sGMRα arises not only through alternative splicing but also through ectodomain shedding of cell surface GMRα.
Empirical Evaluation of a Dynamic Experiment Design Method for Prediction of MHC Class I-Binding Peptides
Authors: Udaka Keiko , Mamitsuka Hiroshi , Nakaseko Yukinobu , Abe Naoki 
Published: April 2014

Abstract
The ability to predict MHC-binding peptides remains limited despite ever expanding demands for specific immunotherapy against cancers, infectious diseases, and autoimmune disorders. Previous analyses revealed position-specific preference of amino acids but failed to detect sequence patterns. Efforts to use computational analysis to identify sequence patterns have been hampered by the insufficiency of the number/quality of the peptide binding data. We propose here a dynamic experiment design to search for sequence patterns that are common to the MHC class I-binding peptides. The method is based on a committee-based framework of query learning using hidden Markov models as its component algorithm. It enables a comprehensive search of a large variety (209) of peptides with a small number of experiments. The learning was conducted in seven rounds of feedback loops, in which our computational method was used to determine the next set of peptides to be analyzed based on the results of the earlier iterations. After these training cycles, the algorithm enabled a real number prediction of MHC binding peptides with an accuracy surpassing that of the hitherto best performing positional scanning method.
Rejection of Syngeneic Colon Carcinoma by CTLs Expressing Single-Chain Antibody Receptors Codelivering CD28 Costimulation
Authors: Haynes Nicole M. , Trapani Joseph A. , Teng Michele W. L. , Jackson Jacob T. , Cerruti Loretta , Jane Stephen M. , Kershaw Michael H. , Smyth Mark J. , Darcy Phillip K. 
Published: April 2014

AbstractA new strategy to improve the therapeutic utility of redirected T cells for cancer involves the development of novel Ag-specific chimeric receptors capable of stimulating optimal and sustained T cell antitumor activity in vivo. Given that T cells require both primary and costimulatory signals for optimal activation and that many tumors do not express critical costimulatory ligands, modified single-chain Ab receptors have been engineered to codeliver CD28 costimulation. In this study, we have compared the antitumor potency of primary T lymphocytes expressing carcinoembryonic Ag (CEA)-reactive chimeric receptors that incorporate either TCR-ζ or CD28/TCR-ζ signaling. Although both receptor-transduced T cell effector populations demonstrated cytolysis of CEA+ tumors in vitro, T cells expressing the single-chain variable fragment of Ig (scFv)-CD28-ζ chimera had a far greater capacity to control the growth of CEA+ xenogeneic and syngeneic colon carcinomas in vivo. The observed enhanced antitumor activity of T cells expressing the scFv-CD28-ζ receptor was critically dependent on perforin and the production of IFN-γ. Overall, this study has illustrated the ability of a chimeric scFv receptor capable of harnessing the signaling machinery of both TCR-ζ and CD28 to augment T cell immunity against tumors that have lost expression of both MHC/peptide and costimulatory ligands in vivo.
CD8 T Cell-Mediated Killing ofCryptococcus neoformansRequires Granulysin and Is Dependent on CD4 T Cells and IL-15
Authors: Ma Ling Ling , Spurrell Jason C. L. , Wang Jian Fei , Neely Graham G. , Epelman Slava , Krensky Alan M. , Mody Christopher H. 
Published: April 2014

AbstractGranulysin is located in the acidic granules of cytotoxic T cells. Although the purified protein has antimicrobial activity against a broad spectrum of microbial pathogens, direct evidence for granulysin-mediated cytotoxicity has heretofore been lacking. Studies were performed to examine the regulation and activity of granulysin expressed by CD8 T cells using Cryptococcus neoformans, which is one of the most common opportunistic pathogens of AIDS patients. IL-15-activated CD8 T cells acquired anticryptococcal activity, which correlated with the up-regulation of granulysin. When granules containing granulysin were depleted using SrCl2, or when the gene was silenced using 21-nt small interfering RNA duplexes, the antifungal effect of CD8 T cells was abrogated. Concanamycin A and EGTA did not affect the antifungal effect, suggesting that the activity of granulysin was perforin independent. Following stimulation by the C. neoformans mitogen, CD8 T cells expressed granulysin and acquired antifungal activity. This activity required CD4 T cells and was dependent upon accessory cells. Furthermore, IL-15 was both necessary and sufficient for granulysin up-regulation in CD8 T cells. These observations are most consistent with a mechanism whereby C. neoformans mitogen is presented to CD4 T cells, which in turn activate accessory cells. The resultant IL-15 activates CD8 T cells to express granulysin, which is responsible for antifungal activity.
Nonsecreted Bacterial Proteins Induce Recall CD8 T Cell Responses But Do Not Serve as Protective Antigens
Authors: Zenewicz Lauren A. , Foulds Kathryn E. , Jiang Jiu , Fan Xin , Shen Hao 
Published: April 2014

Abstract
Secreted or nonsecreted Ag expressed by recombinant Listeria monocytogenes can prime CD8 T cells. However, Ag-specific memory CD8 T cells confer protection against bacteria secreting Ag, but not against bacteria expressing the nonsecreted form of the same Ag. This dichotomy may be explained by a long-standing hypothesis that nonsecreted Ags are less effective than secreted Ags at inducing a protective immune response at the onset of infection. We tested this hypothesis by examining whether these two different forms of Ag induce different primary and secondary CD8 T cell responses. The primary responses to secreted and nonsecreted Ags expanded and contracted almost synchronously, although the responses to nonsecreted Ags were of lower magnitude. These results demonstrate that the kinetics of the CD8 T cell response are similar regardless of whether Ag is accessible to the endogenous MHC class I pathway or can only be presented through cross-presentation. No differences were detected in the CD8 T cell recall response to L. monocytogenes expressing secreted or nonsecreted Ags. Nonsecreted Ags are as effective as secreted Ags at the induction of a rapid recall response by memory CD8 T cells. Thus, the inability of nonsecreted bacterial proteins to serve as protective Ags cannot be attributed to a defective CD8 T cell response.
Inducible Costimulator Protein Controls the Protective T Cell Response Against Listeria monocytogenes
Authors: Mittrücker Hans-Willi , Kursar Mischo , Köhler Anne , Yanagihara Donna , Yoshinaga Steven K. , Kaufmann Stefan H. E. 
Published: April 2014

Abstract
The inducible costimulator protein (ICOS) was recently identified as a costimulatory molecule for T cells. Here we analyze the role of ICOS for the acquired immune response of mice against the intracellular bacterium Listeria monocytogenes. During oral L. monocytogenes infection, low levels of ICOS expression were detected by extracellular and intracellular Ab staining of Listeria-specific CD4+ and CD8+ T cells. Blocking of ICOS signaling with a soluble ICOS-Ig fusion protein markedly impaired the Listeria-specific T cell responses. Compared with control mice, the ICOS-Ig treated mice generated significantly reduced numbers of Listeria-specific CD8+ T cells in spleen and liver, as determined by tetramer and intracellular cytokine staining. In contrast, the specific CD8+ T cell response in the intestinal mucosa did not appear to be impaired by the ICOS-Ig treatment. Analysis of the CD4+ T cell response revealed that ICOS-Ig treatment also affected the specific CD4+ T cell response. When restimulated with listerial Ag in vitro, reduced numbers of CD4+ T cells from infected and ICOS-Ig-treated mice responded with IFN-γ production. The impaired acquired immune response in ICOS-Ig treated mice was accompanied by their increased susceptibility to L. monocytogenes infection. ICOS-Ig treatment drastically enhanced bacterial titers, and a large fraction of mice succumbed to the otherwise sublethal dose of infection. Thus, ICOS costimulation is crucial for protective immunity against the intracellular bacterium L. monocytogenes.