bluuebunny/crossref_metadata_2025_split huggingface dataset:
Vγ1+ T Cells Suppress and Vγ4+ T Cells Promote Susceptibility to Coxsackievirus B3-Induced Myocarditis in Mice
Authors: Huber Sally A. , Graveline Danielle , Newell M. Karen , Born Willi K. , O’Brien Rebecca L. 
Published: April 2014

AbstractCoxsackievirus B3 infections of C57BL/6 mice, which express the MHC class II IA but not IE Ag, results in virus replication in the heart but minimal myocarditis. In contrast, Bl.Tg.Eα mice, which are C57BL/6 mice transgenically induced to express IE Ag, develop significant myocarditis upon Coxsackievirus B3 infection. Despite this difference in inflammatory damage, cardiac virus titers are similar between C57BL/6 and Bl.Tg.Eα mice. Removing γδ T cells from either strain by genetic manipulation (γδ knockout(ko)) changes the disease phenotype. C57BL/6 γδ ko mice show increased myocarditis. In contrast, Bl.Tg.Eα γδ ko mice show decreased cardiac inflammation. Flow cytometry revealed a difference in the γδ cell subsets in the two strains, with Vγ1 dominating in C57BL/6 mice, and Vγ4 predominating Bl.Tg.Eα mice. This suggests that these two Vγ-defined subsets might have different functions. To test this possibility, we used mAb injection to deplete each subset. Mice depleted of Vγ1 cells showed enhanced myocarditis, whereas those depleted of Vγ4 cells suppressed myocarditis. Adoptively transfusing enriched Vγ4+ cells to the C57BL/6 and Bl.Tg.Eα γδ ko strains confirmed that the Vγ4 subset promoted myocarditis. Th subset analysis suggests that Vγ1+ cells biased the CD4+ T cells to a dominant Th2 cell response, whereas Vγ4+ cells biased CD4+ T cells toward a dominant Th1 cell response.
Accumulation of RXRα During Activation of Cycling Human T Lymphocytes: Modulation of RXRE Transactivation Function by Mitogen-Activated Protein Kinase Pathways
Authors: Ishaq Mohammad , Fan Ming , Natarajan Ven 
Published: April 2014

AbstractWe have previously reported that the activation of resting human immature peripheral blood T (PBT) lymphocytes is associated with the loss of retinoid X receptor α (RXRα) expression. In the present study, we have demonstrated that, unlike resting cells, activation of cycling human mature PBT lymphocytes, and T lymphocyte leukemia cell lines is accompanied by the accumulation of RXRα mRNA and protein. Interestingly, cyclosporin A further augmented RXRα expression, indicating the involvement of calcineurin pathways in the process. 9-cis retinoic acid inhibited the accumulation, suggesting that retinoids can regulate the synthesis of their own receptors during T cell activation. Transfection analysis in Jurkat cells, using RXRE-dependent reporter assays, showed that RXRα accumulated during T cell activation was transcriptionally inactive. To investigate the mechanism of such inhibition, the role of two mitogen-activated protein kinase pathways, c-Jun N-terminal kinase (JNK) and extracellular signal-regulated kinase (ERK), in modulating RXRE-dependent transcription, was explored. The expression of constitutively active MAP/ERK kinase kinase 1 (MEKK1) inhibited RXRE-dependent transcription, whereas dominant negative MEKK1 increased the transcription, indicating the involvement of JNK signaling pathways in the process. In contrast, expression of constitutively active MEK1, which activates ERK pathway, enhanced RXRE-dependent activation. When both were activated simultaneously, JNK pathway was dominant over ERK pathway and resulted in inhibition of RXRE-mediated transcription. These data demonstrate a dual regulatory control of RXRα expression during the activation of resting and cycling T lymphocytes and indicate a dynamic balance between JNK and ERK pathways in modulating RXRE-mediated transactivation.
Divergent Roles for CD4+ T Cells in the Priming and Effector/Memory Phases of Adoptive Immunotherapy
Authors: Hu Hong-Ming , Winter Hauke , Urba Walter J. , Fox Bernard A. 
Published: April 2014

AbstractThe requirement for CD4+ Th cells in the cross-priming of antitumor CTL is well accepted in tumor immunology. Here we report that the requirement for T cell help can be replaced by local production of GM-CSF at the vaccine site. Experiments using mice in which CD4+ T cells were eliminated, either by Ab depletion or by gene knockout of the MHC class II β-chain (MHC II KO), revealed that priming of therapeutic CD8+ effector T cells following vaccination with a GM-CSF-transduced B16BL6-D5 tumor cell line occurred independently of CD4+ T cell help. The adoptive transfer of CD8+ effector T cells, but not CD4+ effector T cells, led to complete regression of pulmonary metastases. Regression of pulmonary metastases did not require either host T cells or NK cells. Transfer of CD8+ effector T cells alone could cure wild-type animals of systemic tumor; the majority of tumor-bearing mice survived long term after treatment (&gt;100 days). In contrast, adoptive transfer of CD8+ T cells to tumor-bearing MHC II KO mice improved survival, but eventually all MHC II KO mice succumbed to metastatic disease. WT mice cured by adoptive transfer of CD8+ T cells were resistant to tumor challenge. Resistance was mediated by CD8+ T cells in mice at 50 days, while both CD4+ and CD8+ T cells were important for protection in mice challenged 150 days following adoptive transfer. Thus, in this tumor model CD4+ Th cells are not required for the priming phase of CD8+ effector T cells; however, they are critical for both the complete elimination of tumor and the maintenance of a long term protective antitumor memory response in vivo.
Autoregulation of Human Monocyte-Derived Dendritic Cell Maturation and IL-12 Production by Cyclooxygenase- 2-Mediated Prostanoid Production
Authors: Whittaker Donna S. , Bahjat Keith S. , Moldawer Lyle L. , Clare-Salzler Michael J. 
Published: April 2014

AbstractPG added to cell culture profoundly affect the in vitro maturation and function of monocyte-derived dendritic cells (MDC). Because unstimulated monocytes express cyclooxygenase (COX)-1, and COX-2 when activated, we examined whether MDC express these enzymes and produce prostanoids that autoregulate maturation and IL-12 production. Immature MDC (I-MDC) and mature MDC express COX-1, but, unlike monocytes, both MDC populations constitutively express COX-2. However, COX-2 regulation in both MDC populations differs from monocytes, as IL-4 does not suppress enzyme expression. COX-2 is functional in MDC as a specific inhibitor, NS-398, significantly reduces PGE2 production. I-MDC undergoing maturation with soluble CD40 ligand (sCD40L) increase PGE2 synthesis, but prostanoid synthesis is switched to COX-1. However, with IFN-γ present, sCD40L-stimulated PG metabolism is redirected to COX-2, and PGE2 synthesis increases severalfold. Endogenous PG production by MDC does not regulate CD40, CD80, CD86, or HLA DR expression; however, it does promote MDC maturation, as NS-398 significantly reduces CD83 expression in I-MDC matured with sCD40L/IFN-γ. PG produced through COX-2 also autoregulate IL-12, but the effects are dependent on the MDC maturation state. Blocking COX-2 reduces I-MDC secretion of IL-12p40, whereas it increases IL-12p40 and p70 production by maturing MDC. COX-2-mediated PG production impacts MDC function as maturing these cells in the presence of NS-398 yields MDC that stimulate significantly more IFN-γ in an allogeneic mixed lymphocyte response than MDC matured without this inhibitor. These studies demonstrate that MDC express both COX isoforms constitutively and produce prostanoids, which autoregulate their maturation and function.
Enhancement of T Cell Receptor Signaling by a Mild Oxidative Shift in the Intracellular Thiol Pool
Authors: Hehner Steffen P. , Breitkreutz Raoul , Shubinsky George , Unsoeld Heike , Schulze-Osthoff Klaus , Schmitz M. Lienhard , Dröge Wulf 
Published: April 2014

AbstractExposure of T cells to the macrophage products hydrogen peroxide (HP) or l-lactate (LAC) was previously shown to enhance IL-2 production and to modulate glutathione (GSH) status. We now found that 50 μM HP and 30 mM LAC enhanced strongly the transcription from the IL-2 promoter in Jurkat T cells after stimulation with anti-CD28 together with or without anti-CD3 but not with anti-CD3 Abs alone. Therefore, we used anti-CD3 plus anti-CD28-stimulated cells to investigate the effect of the GSH reductase inhibitor 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU) on the signal cascade. BCNU enhanced the transcription to a similar extent as HP or LAC. Lowering the intracellular GSH/GSH disulfide ratio by BCNU, HP, or NO resulted in all cases in the fulminant enhancement of Jun-N-terminal kinase and p38 mitogen-activated protein kinase but not extracellular signal-regulated kinase 1/2. Jun-N-terminal kinase and NF-κB activation was enhanced through pathways involving Rac, Vav1, PKCΘ, p56lck, p59fyn, and IκB kinases. In a cell-free system, the autophosphorylation of rFyn was stimulated by GSH disulfide but not by HP. These findings suggest that the oxidation of the cellular thiol pool may play a role as an amplifying mechanism for TCR/CD3 signals in immune responses.
Unexpected Autoantibody Production in Membrane Ig-μ-Deficient/lprMice
Authors: Melamed Doron , Miri Engelmayer , Leider Nira , Nemazee David 
Published: April 2014

AbstractIn the B lymphocyte lineage, Fas-mediated cell death is important in controlling activated mature cells, but little is known about possible functions at earlier developmental stages. In this study we found that in mice lacking the IgM transmembrane tail exons (μMT mice), in which B cell development is blocked at the pro-B stage, the absence of Fas or Fas ligand allows significant B cell development and maturation, resulting in high serum Ig levels. These B cells demonstrate Ig heavy chain isotype switching and autoimmune reactivity, suggesting that lack of functional Fas allows maturation of defective and/or self-reactive B cells in μMT/lpr mice. Possible mechanisms that may allow maturation of these B cells are discussed.
Induction and Expression of β-Calcitonin Gene-Related Peptide in Rat T Lymphocytes and Its Significance
Authors: Xing Liyu , Guo Jingxuan , Wang Xian 
Published: April 2014

Abstract
Our previous data have shown that rat lymphocytes can synthesize calcitonin gene-related peptide (CGRP), a neuropeptide. In this study the type, characteristics, and functional role of lymphocyte-derived CGRP were investigated. The results showed that treatment with Con A (4 μg/ml) and recombinant human IL-2 (rhIL-2; 750 U/ml) for 3–5 days induced CGRP synthesis and secretion by lymphocytes from both thymus and mesenteric lymph nodes in a time-dependent manner. Stimulation of these cells with Con A (1–8 μg/ml) or rhIL-2 (94–1500 U/ml) for 5 days induced a significant increase in CGRP secretion in a concentration-dependent manner. The maximal secretion of CGRP with Con A by thymocytes was elevated from 104 ± 11 to 381 ± 44 pg/108 cells, and that by mesenteric lymph node lymphocytes was elevated from 83 ± 10 to 349 ± 25 pg/108 cells, respectively. The maximal CGRP secretion with rhIL-2 by thymocytes was elevated from 116 ± 3 to 607 ± 23 pg/108, and that by mesenteric lymph node lymphocytes was elevated from 117 ± 9 to 704 ± 37 pg/108 cells, respectively. The nucleotide sequencing study showed that lymphoid cells expressed β-CGRP cDNA only. The levels of β-CGRP mRNA in mitogen-stimulated lymphocytes of both sources were also increased. However, LPS had no such effect on either source of cells. hCGRP8–37 (2.0 μM), a CGRP1 receptor antagonist, enhanced Con A-induced proliferation and IL-2 release of thymocytes by 41.3 and 35.8% over those induced by Con A alone, respectively. The data suggest that T lymphocyte mitogens can induce the production of endogenous β-CGRP from T lymphocytes, which may partially inhibit the proliferation and IL-2 release of rat T lymphocyte under immune challenges.
Distinct Human T Cell Repertoires Mediate Immediate and Delayed-Type Hypersensitivity to theTrichophytonAntigen, Tri r 2
Authors: Woodfolk Judith A. , Sung Sun-Sang J. , Benjamin David C. , Lee Jae K. , Platts-Mills Thomas A. E. 
Published: April 2014

AbstractThe 29-kDa subtilase homologue, Tri r 2, derived from the dermatophyte fungus Trichophyton rubrum, exhibits unique immunologic characteristics in its ability to elicit immediate (IH) and delayed-type (DTH) hypersensitivity skin tests in different individuals. Thus, Tri r 2 provides a model for comparing the T cell repertoire in subjects with distinct immune responses to a single Ag. Recombinant Tri r 2 produced as a GST fusion protein in Escherichia coli stimulated strong in vitro lymphoproliferative responses in 10 IH and 10 DTH responders. Patterns of T cell epitope recognition were compared between skin test groups using 28 overlapping peptides (each in 12 replicate wells) derived from Tri r 2 to stimulate T lymphocyte proliferation in vitro. Peptide 5 (P5; aa 41–60) induced the strongest response in DTH subjects and showed the largest difference between DTH and IH responders in proliferation (mean standardized index, 2.22 and 0.82, respectively; p = 0.0047) and number of positive wells (81 vs 12). Responses to P5 were associated with diverse HLA haplotypes. These results showed that P5 contains an immunodominant epitope specifically associated with DTH and that this peptide is recognized in a permissive manner. Cross-validated linear discriminant analysis using T cell proliferative responses to two regions of Tri r 2 (aa 51–90 and 231–270) gave a 95% predictive accuracy for classification of subjects into IH or DTH groups. We conclude that different immune responses to Trichophyton are mediated by distinct T cell repertoires between individuals with IH and DTH reactions to Tri r 2.
Notch Signaling Enhances Survival and Alters Differentiation of 32D Myeloblasts
Authors: Tan-Pertel Hongying Tina , Walker Liberty , Browning Damaris , Miyamoto Alison , Weinmaster Gerry , Gasson Judith C. 
Published: April 2014

AbstractThe Notch transmembrane receptors play important roles in precursor survival and cell fate specification during hematopoiesis. To investigate the function of Notch and the signaling events activated by Notch in myeloid development, we expressed truncated forms of Notch1 or Notch2 proteins that either can or cannot activate the core binding factor 1 (CBF1) in 32D (clone 3) myeloblasts. 32D cells proliferate as blasts in the presence of the cytokines, GM-CSF or IL-3, but they initiate differentiation and undergo granulopoiesis in the presence of granulocyte CSF (G-CSF). 32D cells expressing constitutively active forms of Notch1 or Notch2 proteins that signal through the CBF1 pathway maintained significantly higher numbers of viable cells and exhibited less cell death during G-CSF induction compared with controls. They also displayed enhanced entry into granulopoiesis, and inhibited postmitotic terminal differentiation. In contrast, Notch1 constructs that either lacked sequences necessary for CBF1 binding or that failed to localize to the nucleus had little effect. Elevated numbers of viable cells during G-CSF treatment were also observed in 32D cells overexpressing the basic helix-loop-helix protein (bHLH), HES1, consistent with activation of the CBF1 pathway. Taken together, our data suggest that Notch signaling enhances 32D cell survival, promotes entry into granulopoiesis, and inhibits postmitotic differentiation through a CBF1-dependent pathway.
Identification and Characterization of a β Proteasome Subunit Cluster in the Japanese Pufferfish (Fugu rubripes)
Authors: Clark Melody S. , Pontarotti Pierre , Gilles André , Kelly Alison , Elgar Greg 
Published: April 2014

AbstractThe low molecular mass polypeptide (LMP2, LMP7, and MECL-1) genes code for β-type subunits of the proteasome, a multimeric complex that degrades proteins into peptides as part of the MHC class I-mediated Ag-presenting pathway. These gene products are up-regulated in response to infection by IFN-γ and replace the corresponding constitutively expressed subunits (X, Y, and Z) during the immune response. In humans, the LMP2 and LMP7 genes both reside within the class II region of the MHC (6p21.3), while MECL-1 is located at 16q22.1. In the present study, we have identified all three IFN-γ-regulated β-type proteasome subunits in Fugu, which are present as a cluster within the Fugu MHC class I region. We show that in this species, LMP7, LMP2, and MECL-1 are linked. Also within this cluster is an LMP2-like subunit (which seems specific to all teleosts tested to date) and a closely linked LMP7 pseudogene, indicating that within Fugu and potentially other teleosts, there has been an additional regional duplication involving these genes.
Metalloprotease-Mediated Shedding of Enzymatically Active Mouse ecto-ADP-ribosyltransferase ART2.2 Upon T Cell Activation
Authors: Kahl Sarah , Nissen Marion , Girisch Roman , Duffy Ted , Leiter Edward H. , Haag Friedrich , Koch-Nolte Friedrich 
Published: April 2014

AbstractT cells proteolytically shed the ectodomains of several cell surface proteins and, thereby, can alter their responsiveness and can release soluble intercellular regulators. ART2.2 is a GPI-anchored ecto-ADP-ribosyltransferase (ART) related to ADP-ribosylating bacterial toxins. ART2.2 is expressed exclusively by mature T cells. Here we show that ART2.2 is shed from the cell surface in enzymatically active form upon activation of T cells. Shedding of ART2.2 resembles that of L-selectin (CD62L) in dose response, kinetics of release, and sensitivity to the metalloprotease inhibitor Immunex Compound 3, suggesting that ART2.2, like CD62L, is cleaved by TNF-α-converting enzyme or by another metalloprotease. ART2.2 shed from activated T cells migrates slightly faster in SDS-PAGE analyses than does ART2.2 released upon cleavage of the GPI anchor. This indicates that shedding of ART2.2 is mediated by proteolytic cleavage close to its membrane anchor. Shed ART2.2 is enzymatically active and ADP-ribosylates several substrates in vitro. Thus, shedding of ART2.2 releases a potential intercellular regulator. Finally, using a new FACS assay for monitoring ADP-ribosylation of cell surface proteins, we demonstrate that shedding of ART2.2 correlates with a reduced sensitivity of T cell surface proteins to ADP-ribosylation. Our findings suggest that by shedding ART2.2 the activated T cell not only releases a potential intercellular regulator but also may alter its responsiveness to immune regulation by ART2.2-mediated ADP-ribosylation of cell surface proteins.
Changing the Antigen Binding Specificity by Single Point Mutations of an Anti-p24 (HIV-1) Antibody
Authors: Winkler Karsten , Kramer Achim , Küttner Gabriele , Seifert Martina , Scholz Christa , Wessner Helga , Schneider-Mergener Jens , Höhne Wolfgang 
Published: April 2014

AbstractThe murine mAb CB4-1 raised against p24 (HIV-1) recognizes a linear epitope of the HIV-1 capsid protein. Additionally, CB4-1 exhibits cross-reactive binding to epitope-homologous peptides and polyspecific reactions to epitope nonhomologous peptides. Crystal structures demonstrate that the epitope peptide (e-pep) and the nonhomologous peptides adopt different conformations within the binding region of CB4-1. Site-directed mutagenesis of the fragment variable (Fv) region was performed using a single-chain (sc)Fv construct of CB4-1 to analyze binding contributions of single amino acid side chains toward the e-pep and toward one epitope nonhomologous peptide. The mutations of Ab amino acid side chains, which are in direct contact with the Ag, show opposite influences on the binding of the two peptides. Whereas the affinity of the e-pep to the CB4-1 scFv mutant heavy chain variable region Tyr32Ala is decreased 250-fold, the binding of the nonhomologous peptide remains unchanged. In contrast, the mutation light chain variable region Phe94Ala reduces the affinity of the nonhomologous peptide 10-fold more than it does for the e-pep. Thus, substantial changes in the specificity can be observed by single amino acid exchanges. Further characterization of the scFv mutants by substitutional analysis of the peptides demonstrates that the effect of a mutation is not restricted to contact residues. This method also reveals an inverse compensatory amino acid exchange for the nonhomologous peptide which increases the affinity to the scFv mutant light chain variable region Phe94Ala up to the level of the e-pep affinity to the wild-type scFv.
Rapid Recruitment of Neutrophils Containing Prestored IL-12 During Microbial Infection
Authors: Bliss Susan K. , Butcher Barbara A. , Denkers Eric Y. 
Published: April 2014

AbstractNeutrophils are well known to rapidly migrate to foci of infection, where they exert microbicidal functions. We sought to determine whether neutrophils responding to in vivo infection with the protozoan pathogen Toxoplasma gondii were capable of IL-12 production as suggested by recent in vitro studies. Intraperitoneal infection induced a neutrophil influx by 4 h, accompanied by ex vivo IL-12 p40 and p70 release. Approximately 85% of the neutrophils displayed intracellular stores of IL-12, as determined by flow cytometry and confocal fluorescence microscopy. Neutrophils from IFN-γ knockout mice also expressed IL-12, ruling out an IFN-γ-priming requirement. Neither infected nor uninfected peritoneal macrophages displayed intracellular IL-12, but these cells were strongly IL-10+. Infection per se was unnecessary for IL-12 production because peritoneal and peripheral blood neutrophils from uninfected animals contained IL-12+ populations. Expression of the granulocyte maturation marker Gr-1 (Ly-6G) was correlated with IL-12 production. Mice depleted of their granulocytes by mAb administration at the time of infection had decreased serum levels of IL-12 p40. These results suggest a model in which neutrophils with prestored IL-12 are rapidly mobilized to an infection site where they are triggered by the parasite to release cytokine. Our findings place neutrophils prominently in the cascade of early events leading to IL-12-dependent immunity to T. gondii.
Novel Mechanism of Antibody-Independent Complement Neutralization of Herpes Simplex Virus Type 1
Authors: Friedman Harvey M. , Wang Liyang , Pangburn Michael K. , Lambris John D. , Lubinski John 
Published: April 2014

AbstractThe envelope surface glycoprotein C (gC) of HSV-1 interferes with the complement cascade by binding C3 and activation products C3b, iC3b, and C3c, and by blocking the interaction of C5 and properdin with C3b. Wild-type HSV-1 is resistant to Ab-independent complement neutralization; however, HSV-1 mutant virus lacking gC is highly susceptible to complement resulting in ≥100-fold reduction in virus titer. We evaluated the mechanisms by which complement inhibits HSV-1 gC null virus to better understand how gC protects against complement-mediated neutralization. C8-depleted serum prepared from an HSV-1 and -2 Ab-negative donor neutralized gC null virus comparable to complement-intact serum, indicating that C8 and terminal lytic activity are not required. In contrast, C5-depleted serum from the same donor failed to neutralize gC null virus, supporting a requirement for C5. EDTA-treated serum did not neutralize gC null virus, indicating that complement activation is required. Factor D-depleted and C6-depleted sera neutralized virus, suggesting that the alternative complement pathway and complement components beyond C5 are not required. Complement did not aggregate virus or block attachment to cells. However, complement inhibited infection before early viral gene expression, indicating that complement affects one or more of the following steps in virus replication: virus entry, uncoating, DNA transport to the nucleus, or immediate early gene expression. Therefore, in the absence of gC, HSV-1 is readily inhibited by complement by a C5-dependent mechanism that does not require viral lysis, aggregation, or blocking virus attachment.