bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Role of Structurally Conserved Class I MHC in Tumor Rejection: Contribution of the Q8 Locus
Authors: Chiang Eugene Y. , Stroynowski Iwona 
Published: April 2014

AbstractThe mouse multimember family of Qa-2 oligomorphic class I MHC genes is continuously undergoing duplications and deletions that alter the number of the two “prototype” Qa-2 sequences, Q8 and Q9. The frequent recombination events within the Q region lead to strain-specific modulation of the cumulative Qa-2 expression levels. Q9 protects C57BL/6 hosts from multiple disparate tumors and functions as a major CTL restriction element for shared tumor-associated Ags. We have now analyzed functional and structural properties of Q8, a class I MHC that differs significantly from Q9 in the peptide-binding, CTL-interacting α1 and α2 regions. Unexpectedly, we find that the extracellular domains of Q8 and Q9 act similarly during primary and secondary rejection of tumors, are recognized by cross-reactive antitumor CTL, have overlapping peptide-binding motifs, and are both assembled via the transporter associated with the Ag processing pathway. These findings suggest that shared Ag-presenting functions of the “odd” and “even” Qa-2 loci may contribute to the selective pressures shaping the haplotype-dependent quantitative variation of Qa-2 protein expression.
Defective Activation of Protein Kinase C and Ras-ERK Pathways Limits IL-2 Production and Proliferation by CD4+CD25+ Regulatory T Cells
Authors: Hickman Somia P. , Yang Jaeseok , Thomas Rajan M. , Wells Andrew D. , Turka Laurence A. 
Published: April 2014

AbstractNaturally occurring CD4+CD25+ regulatory T cells (Tregs), which play an important role in the maintenance of self-tolerance, proliferate poorly and fail to produce IL-2 following stimulation in vitro with peptide-pulsed or anti-CD3-treated APCs. When TCR proximal and distal signaling events were examined in Tregs, we observed impairments in the amplitude and duration of tyrosine phosphorylation when compared with the response of CD4+CD25− T cells. Defects were also seen in the activity of phospholipase C-γ and in signals downstream of this enzyme including calcium mobilization, NFAT, NF-κB, and Ras-ERK-AP-1 activation. Enhanced stimulation of diacylglycerol-dependent pathways by inhibition of diacylglycerol metabolism could overcome the “anergic state” and support the ability of Tregs to up-regulate CD69, produce IL-2, and proliferate. Our results demonstrate that Tregs maintain their hyporesponsive state by suppressing the induction and propagation of TCR-initiated signals to control the accumulation of second messengers necessary for IL-2 production and proliferation.
Intradermal Delivery of Adenoviral Type-35 Vectors Leads to High Efficiency Transduction of Mature, CD8+ T Cell-Stimulating Skin-Emigrated Dendritic Cells
Authors: de Gruijl Tanja D. , Ophorst Olga J. A. E. , Goudsmit Jaap , Verhaagh Sandra , Lougheed Sinéad M. , Radosevic Katarina , Havenga Menzo J. E. , Scheper Rik J. 
Published: April 2014

AbstractRecombinant adenovirus (Ad) type 35 (rAd35) shows great promise as vaccine carrier with the advantage of low pre-existing immunity in human populations, in contrast to the more commonly used rAd5 vector. The rAd35 vector uses CD46 as a high-affinity receptor, which, unlike the rAd5 receptor, is expressed on human dendritic cells (DC), the most powerful APCs identified to date. In this study, we show that in contrast to rAd5, rAd35 infects migrated and mature CD83+ cutaneous DC with high efficiency (up to 80%), when delivered intradermally in an established human skin explant model. The high transduction efficiency is in line with high expression levels of CD46 detected on migratory cutaneous DC, which proved to be further increased upon intradermal administration of GM-CSF and IL-4. As compared with Ad5, these Ad35 infection characteristics translate into higher absolute numbers of skin-emigrated DC per explant that both express the transgene and are phenotypically mature. Finally, we demonstrate that upon intracutaneous delivery of a rAd35 vaccine encoding the circumsporozoite (CS) protein of Plasmodium falciparum, emigrated DC functionally express and process CS-derived epitopes and are capable of activating specific CD8+ effector T cells, as evidenced by activation of an HLA-A2-restricted CS-specific CD8+ T cell clone. Collectively, these data demonstrate the utility of rAd35 vectors for efficient in vivo human DC transduction.
Constitutive Activation of STAT5 Supersedes the Requirement for Cytokine and TCR Engagement of CD4+ T Cells in Steady-State Homeostasis
Authors: Taylor Devon K. , Walsh Patrick T. , LaRosa David F. , Zhang Jidong , Burchill Matthew A. , Farrar Michael A. , Turka Laurence A. 
Published: April 2014

AbstractThe transcription factor STAT5 is one of several signaling mediators activated via common γ-chain cytokine receptors. As such, it plays an important role in lymphocyte survival and proliferation during normal homeostasis as well as under lymphopenic conditions. Transgenic mice expressing a constitutively activated form of STAT5b have been shown previously to contain increased numbers of peripheral CD4+CD25− T cells. To define the mechanism(s) for this occurrence, we have used adoptive transfer studies to examine the effects of STAT5 activity on steady-state CD4+ T cell homeostasis. We observed that constitutive STAT5 signaling induced 4- to 7-fold increased levels of basal steady-state proliferation, which was accompanied by a comparable increase in T cell recovery. Most strikingly, steady-state CD4 T cell proliferation occurred independently of both MHC class II and IL-15. These observations demonstrate that the STAT5-driven pathway is important to lymphocyte homeostasis and can supersede the need for both TCR engagement and cytokine stimulation. This suggests that the need for TCR stimulation to induce common γ-chain cytokine receptor expression, and thus STAT5 activation, is a key factor in maintaining normal CD4+ T cell homeostasis.
Impaired Intracellular Calcium Mobilization and NFATc1 Availability in Tolerant Anti-Insulin B Cells
Authors: Acevedo-Suárez Carlos A. , Kilkenny Dawn M. , Reich Martha B. , Thomas James W. 
Published: April 2014

AbstractB lymphocytes that recognize soluble self-Ags are routinely found in normal individuals in a functionally inactive or anergic state. Current models indicate that this tolerant state is maintained by interactions with self-Ags that uncouple the BCR from downstream signaling pathways and increase levels of free calcium. Contrary to this expectation, B cells that harbor anti-insulin Ig transgenes (125Tg) are maintained in a tolerant state even though free calcium levels remain normal and tyrosine kinase substrate phosphorylation is preserved following BCR stimulation. Under basal conditions, intracellular levels of inositol 1,4,5-trisphosphate are increased and NFATc1 levels are reduced in 125Tg B cells. The 125Tg B cells are markedly impaired in their ability to mobilize calcium upon stimulation with ionomycin, and BCR-induced calcium mobilization from internal stores is decreased. In contrast, poisoning intracellular calcium pumps with thapsigargin increases calcium mobilization in 125Tg B cells. Changes in calcium signaling are accompanied by a failure of 125Tg B cells to translocate NFATc1 into the nucleus following stimulation with either anti-IgM or ionomycin. Thus, disassociation of BCR from multiple signaling pathways is not essential for maintaining tolerance in anti-insulin 125Tg B cells. Rather, BCRs that are occupied by autologous insulin deliver signals that induce changes in intracellular calcium mobilization and maintain tolerance by preventing activation of key transcription factors such as NFAT.
Opposite Fate of Endocytosed CCR7 and Its Ligands: Recycling versus Degradation
Authors: Otero Carolina , Groettrup Marcus , Legler Daniel F. 
Published: April 2014

AbstractThe chemokine receptor CCR7 and its ligands CCL19 and CCL21 play a crucial role for the homing of lymphocytes and dendritic cells to secondary lymphoid tissues. Nevertheless, how CCR7 senses the gradient of chemokines and how migration is terminated are poorly understood. In this study, we demonstrate that CCR7(-GFP) is endocytosed into early endosomes containing transferrin receptor upon CCL19 binding, but less upon CCL21 triggering. Internalization of CCR7 was independent of lipid rafts but relied on dynamin and Eps15 and was inhibited by hypertonic sucrose, suggesting clathrin-dependent endocytosis. After chemokine removal, internalized CCR7 recycled back to the plasma membrane and was able to mediate migration again. In contrast, internalized CCL19 was sorted to lysosomes for degradation, showing opposite fate for endocytosed CCR7 and its ligand.
TGF-β-Mediated Suppression by CD4+CD25+ T Cells Is Facilitated by CTLA-4 Signaling
Authors: Oida Takatoku , Xu LiLi , Weiner Howard L. , Kitani Atsushi , Strober Warren 
Published: April 2014

AbstractCD4+CD25+ T cells play a pivotal role in immunological homeostasis by their capacity to exert immunosuppressive activity. However, the mechanism by which these cells function is still a subject for debate. We previously reported that surface (membrane) TGF-β produced by CD4+CD25+ T cells was an effector molecule mediating suppressor function. We now support this finding by imaging surface TGF-β on Foxp3+CD4+CD25+ T cells in confocal fluorescence microscopy. Then, using a TGF-β-sensitive mink lung epithelial cell (luciferase) reporter system, we show that surface TGF-β can be activated to signal upon cell-cell contact. Moreover, if such TGF-β signaling is blocked in an in vitro assay of CD4+CD25+ T cell suppression by a specific inhibitor of TGF-βRI, suppressor function is also blocked. Finally, we address the role of CTLA-4 in CD4+CD25+ T cell suppression, showing first that whereas anti-CTLA-4 does not block in vitro suppressor function, it does complement the blocking activity of anti-TGF-β. We then show with confocal fluorescence microscopy that incubation of CD4+CD25+ T cells with anti-CTLA-4- and rB7-1/Fc-coated beads results in accumulation of TGF-β at the cell-bead contact site. This suggests that CTLA-4 signaling facilitates TGF-β-mediated suppression by intensifying the TGF-β signal at the point of suppressor cell-target cell interaction.
Distinct Responses of Lung and Spleen Dendritic Cells to the TLR9 Agonist CpG Oligodeoxynucleotide
Authors: Chen Li , Arora Meenakshi , Yarlagadda Manohar , Oriss Timothy B. , Krishnamoorthy Nandini , Ray Anuradha , Ray Prabir 
Published: April 2014

AbstractDendritic cells (DCs) sense various components of invading pathogens via pattern recognition receptors such as TLRs. CpG oligodeoxynucleotides (ODNs), which mimic bacterial DNA, inhibit allergic airways disease and promote responses in the spleen to bacterial components. Because many TLR agonists are currently being tested for potential therapeutic effects, it is important to characterize the expression and function of TLRs in different tissues. We show that both myeloid and plasmacytoid DCs in the spleen express TLR9, the receptor for CpG ODNs, but lung DCs show no detectable expression in either subset. TLR4 expression in contrast was detected on both lung and spleen DCs. LPS was superior to CpG ODN in increasing the allostimulatory potential of lung DCs and their expression of CD40. However, both agonists efficiently stimulated spleen DCs. CpG ODNs administered to mice efficiently inhibited Th2 cytokine production both in the lung draining lymph node and in the spleen. Surprisingly, inhibition of Th2 cytokine production was evident despite high levels of expression of GATA-3 and additional transcription factors that regulate Th2 responses. Although in the spleen CpG ODNs induced IL-6, a key cytokine induced via TLR9-MyD88 signaling, no IL-6 was detectable in lung LN cells. These studies show for the first time that lung DCs lack TLR9 expression, but, despite this deficiency, CpG ODNs induce potent inhibitory effects on Th2 cytokine production in the lung without inducing expression of the proinflammatory cytokine, IL-6, which has been linked to chronic diseases in the lung and the gut.
Cyclooxygenase-2 Inhibitor Enhances the Efficacy of a Breast Cancer Vaccine: Role of IDO
Authors: Basu Gargi D. , Tinder Teresa L. , Bradley Judy M. , Tu Tony , Hattrup Christine L. , Pockaj Barbara A. , Mukherjee Pinku 
Published: April 2014

AbstractWe report that administration of celecoxib, a specific cyclooxygenase-2 (COX-2) inhibitor, in combination with a dendritic cell-based cancer vaccine significantly augments vaccine efficacy in reducing primary tumor burden, preventing metastasis, and increasing survival. This combination treatment was tested in MMTV-PyV MT mice that develop spontaneous mammary gland tumors with metastasis to the lungs and bone marrow. Improved vaccine potency was associated with an increase in tumor-specific CTLs. Enhanced CTL activity was attributed to a significant decrease in levels of tumor-associated IDO, a negative regulator of T cell activity. We present data suggesting that inhibiting COX-2 activity in vivo regulates IDO expression within the tumor microenvironment; this is further corroborated in the MDA-MB-231 human breast cancer cell line. Thus, a novel mechanism of COX-2-induced immunosuppression via regulation of IDO has emerged that may have implications in designing future cancer vaccines.
Activation of Murine CD4+ and CD8+ T Lymphocytes Leads to Dramatic Remodeling ofN-Linked Glycans
Authors: Comelli Elena M. , Sutton-Smith Mark , Yan Qi , Amado Margarida , Panico Maria , Gilmartin Tim , Whisenant Thomas , Lanigan Caroline M. , Head Steven R. , Goldberg David , Morris Howard R. , Dell Anne , Paulson James C. 
Published: April 2014

AbstractDifferentiation and activation of lymphocytes are documented to result in changes in glycosylation associated with biologically important consequences. In this report, we have systematically examined global changes in N-linked glycosylation following activation of murine CD4 T cells, CD8 T cells, and B cells by MALDI-TOF mass spectrometry profiling, and investigated the molecular basis for those changes by assessing alterations in the expression of glycan transferase genes. Surprisingly, the major change observed in activated CD4 and CD8 T cells was a dramatic reduction of sialylated biantennary N-glycans carrying the terminal NeuGcα2-6Gal sequence, and a corresponding increase in glycans carrying the Galα1-3Gal sequence. This change was accounted for by a decrease in the expression of the sialyltransferase ST6Gal I, and an increase in the expression of the galactosyltransferase, α1-3GalT. Conversely, in B cells no change in terminal sialylation of N-linked glycans was evident, and the expression of the same two glycosyltransferases was increased and decreased, respectively. The results have implications for differential recognition of activated and unactivated T cells by dendritic cells and B cells expressing glycan-binding proteins that recognize terminal sequences of N-linked glycans.
E2A Promotes the Survival of Precursor and Mature B Lymphocytes
Authors: Lazorchak Adam S. , Wojciechowski Jason , Dai Meifang , Zhuang Yuan 
Published: April 2014

Abstract
The basic helix-loop-helix transcription factor E2A is an essential regulator of B lymphocyte lineage commitment and is required to activate the expression of numerous B lineage-specific genes. Studies involving ectopic expression of Id proteins, which inhibit E2A as well as other basic helix-loop-helix proteins such as HEB, suggest additional roles of E2A at later stages of B cell development. We use E2A-deficient and E2A and HEB double-deficient pre-B cell lines to directly assess the function of E2A and HEB in B cell development after lineage commitment. We show that, in contrast to the established role of E2A in lineage commitment, elimination of E2A and HEB in pre-B cell lines has only a modest negative impact on B lineage gene expression. However, E2A single and E2A and HEB double-deficient but not HEB single-deficient cell lines show dramatically enhanced apoptosis upon growth arrest. To address the possible role of E2A in the regulation of B cell survival in vivo, we crossed IFN-inducible Cre-transgenic mice to E2A conditional mice. Cre-mediated E2A deletion resulted in a block in bone marrow B cell development and a significant reduction in the proportion and total number of splenic B cells in these mice. We show that Cre-mediated deletion of E2A in adoptively transferred mature B cells results in the rapid depletion of the transferred population within 24 h of Cre induction. These results reveal that E2A is not required to maintain B cell fate but is essential in promoting pre-B and B cell survival.
CD8+ T Lymphocyte-Mediated Loss of Marginal Metallophilic Macrophages following Infection withPlasmodium chabaudi chabaudi AS
Authors: Beattie Lynette , Engwerda Christian R. , Wykes Michelle , Good Michael F. 
Published: April 2014

AbstractThe splenic architecture is essential for the quick resolution of a primary infection with Plasmodium. A critical component of this architecture is the marginal zone (MZ), an area of the spleen that separates the reticuloendothelial red pulp of the spleen from the lymphoid white pulp compartment. There are two unique macrophage populations found in the MZ: MZ macrophages (MZM) found on the outer border of the MZ, and marginal metallophilic macrophages (MMM) found on the inner border, adjacent to the white pulp. We investigated the homeostasis of MMM and MZM following infection with Plasmodium chabaudi and demonstrated that a complete loss of both MMM and MZM occurred by the time of peak parasitemia, 8 days after infection. The loss was not induced by up-regulation of the inflammatory cytokines TNF or IFN-γ. In contrast, following only CD8+ T cell depletion (not dendritic cell), MMM but not MZM were retained, implicating CD8+ T cells in the P. chabaudi-induced loss of MMM. Retention of MMM occurred in mice deficient in CD95, CD95-ligand, and perforin, indicating that these signals are involved in the death pathway of MMM. These data have significant implications for the understanding of the immune-mediated pathology of the spleen as a result of infection with Plasmodium.
Nuclear Accumulation of cRel following C-Terminal phosphorylation by TBK1/IKKε
Authors: Harris Jennifer , Olière Stéphanie , Sharma Sonia , Sun Qiang , Lin Rongtuan , Hiscott John , Grandvaux Nathalie 
Published: April 2014

Abstract
The NF-κB transcription factors are key regulators of immunomodulatory, cell cycle, and developmental gene regulation. NF-κB activity is mainly regulated through the phosphorylation of IκB by the IκB kinase (IKK) complex IKKαβγ, leading to proteasome-mediated degradation of IκB, nuclear translocation of NF-κB dimers, DNA binding, and gene induction. Additionally, direct posttranslational modifications of NF-κB p65 and cRel subunits involving C-terminal phosphorylation has been demonstrated. The noncanonical IKK-related homologs, TNFR-associated factor family member-associated NF-κB activator (TANK)-binding kinase (TBK)1 and IKKε, are also thought to play a role in NF-κB regulation, but their functions remain unclear. TBK1 and IKKε were recently described as essential regulators of IFN gene activation through direct phosphorylation of the IFN regulatory factor-3 and -7 transcription factors. In the present study, we sought to determine whether IKKε and TBK1 could modulate cRel activity via phosphorylation. TBK1 and IKKε directly phosphorylate the C-terminal domain of cRel in vitro and in vivo and regulate nuclear accumulation of cRel, independently of the classical IκB/IKK pathway. IκBα degradation is not affected, but rather IKKε-mediated phosphorylation of cRel leads to dissociation of the IκBα-cRel complex. These results illustrate a previously unrecognized aspect of cRel regulation, controlled by direct IKKε/TBK1 phosphorylation.
Local CD11c+ MHC Class II− Precursors Generate Lung Dendritic Cells during Respiratory Viral Infection, but Are Depleted in the Process
Authors: Wang Hongwei , Peters Nina , Laza-Stanca Vasile , Nawroly Niga , Johnston Sebastian L. , Schwarze Jürgen 
Published: April 2014

Abstract
Increases in numbers of lung dendritic cells (DC) observed during respiratory viral infections are assumed to be due to recruitment from bone marrow precursors. No local production has been demonstrated. In this study, we isolated defined populations of murine lung cells based on CD11c and MHC class II (MHC II) expression. After culture for 12 days with GM-CSF, we analyzed cell numbers, DC surface markers, and Ag-presenting capacity. Only CD11c+ MHC II− cells from naive mice proliferated, yielding myeloid DC, which induced Ag-specific proliferation of naive T cells. After respiratory syncytial virus (RSV) infection, numbers of pulmonary CD11c+ MHC II− precursor cells were significantly reduced and DC could not be generated. Moreover, RSV infection prevented subsequent in vivo expansion of pulmonary DC in response to influenza infection or LPS treatment. These results provide direct evidence of local generation of fully functional myeloid DC in the lung from CD11c+ MHC II− precursor cells that are depleted by RSV infection, leading to an inability to expand lung DC numbers in response to subsequent viral infection or exposure to bacterial products. This depletion of local DC precursors in respiratory viral infections may be important in explaining complex interactions between multiple and intercurrent pulmonary infections.
Subunit Recombinant Vaccine Protects against Monkeypox
Authors: Heraud Jean-Michel , Edghill-Smith Yvette , Ayala Victor , Kalisz Irene , Parrino Janie , Kalyanaraman Vaniambadi S. , Manischewitz Jody , King Lisa R. , Hryniewicz Anna , Trindade Christopher J. , Hassett Meredith , Tsai Wen-Po , Venzon David , Nalca Aysegul , Vaccari Monica , Silvera Peter , Bray Mike , Graham Barney S. , Golding Hana , Hooper Jay W. , Franchini Genoveffa 
Published: April 2014

Abstract
The smallpox vaccine Dryvax, a live vaccinia virus (VACV), protects against smallpox and monkeypox, but is contraindicated in immunocompromised individuals. Because Abs to VACV mediate protection, a live virus vaccine could be substituted by a safe subunit protein-based vaccine able to induce a protective Ab response. We immunized rhesus macaques with plasmid DNA encoding the monkeypox orthologs of the VACV L1R, A27L, A33R, and B5R proteins by the intradermal and i.m. routes, either alone or in combination with the equivalent recombinant proteins produced in Escherichia coli. Animals that received only DNA failed to produce high titer Abs, developed innumerable skin lesions after challenge, and died in a manner similar to placebo controls. By contrast, the animals vaccinated with proteins developed moderate to severe disease (20–155 skin lesions) but survived. Importantly, those immunized with DNA and boosted with proteins had mild disease with 15 or fewer lesions that resolved within days. DNA/protein immunization elicited Th responses and binding Ab titers to all four proteins that correlated negatively with the total lesion number. The sera of the immunized macaques recognized a limited number of linear B cell epitopes that are highly conserved among orthopoxviruses. Their identification may guide future efforts to develop simpler, safer, and more effective vaccines for monkeypox and smallpox.