bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Apoptotic Protease-Activating Factor 1-Mediated Pathway of Apoptosis Is Dispensable for Negative Selection of Thymocytes
Authors: Hara Hiromitsu , Takeda Atsunobu , Takeuchi Michiyo , Wakeham Andrew C. , Itié Annick , Sasaki Masafumi , Mak Tak W. , Yoshimura Akihiko , Nomoto Kikuo , Yoshida Hiroki 
Published: April 2014

Abstract
Negative selection is a process to delete potentially autoreactive clones in developing thymocytes. Programmed cell death or apoptosis is thought to play an important role in this selection process. In this study, we investigated the role of apoptotic protease-activating factor 1 (Apaf1), a mammalian homologue of CED-4, in programmed cell death during the negative selection in thymus. There was no developmental abnormality in thymocytes from newborn Apaf1−/− mice in terms of CD4 and CD8 expression pattern and thymocyte number. Clonal deletion by endogenous male H-Y Ag of Apaf1-deficient thymocytes with transgenic expression of H-Y Ag-specific TCRs (H-Y Tg/Apaf1−/− thymocytes) was normally observed in lethally irradiated wild-type mice reconstituted with fetal liver-derived hemopoietic stem cells. Clonal deletion induced in vitro by a bacterial superantigen was also normal in fetal thymic organ culture. Thus, Apaf1-mediated pathway of apoptosis is dispensable for the negative selection of thymocytes. However, H-Y Tg/Apaf1−/− thymocytes showed partial resistance to H-Y peptide-induced deletion in vitro as compared with H-Y Tg/Apaf1+/− thymocytes, implicating the Apaf1-mediated apoptotic pathway in the negative selection in a certain situation. In addition, the peptide-induced deletion was still observed in H-Y Tg/Apaf1−/− thymocytes in the presence of a broad spectrum caspase inhibitor, z-VAD-fmk, suggesting the presence of caspase-independent cell death pathway playing roles during the negative selection. We assume that mechanisms for the negative selection are composed of several cell death pathways to avoid failure of elimination of autoreactive clones.
Transgenic Expression of the p16INK4a Cyclin-Dependent Kinase Inhibitor Leads to Enhanced Apoptosis and Differentiation Arrest of CD4−CD8− Immature Thymocytes
Authors: Lagresle Chantal , Gardie Betty , Eyquem Stéphanie , Fasseu Magali , Vieville Jean-Claude , Pla Marika , Sigaux François , Bories Jean-Christophe 
Published: April 2014

Abstract
In the thymus, T cell development proceeds by successive steps of differentiation, expansion, and selection. Control of thymocyte proliferation is critical to insure the full function of the immune system and to prevent T cells from transformation. Deletion of the cell cycle inhibitor p16INK4a is frequently observed in human T cell neoplasias and, in mice, gene targeted inactivation of the Ink4a locus enhances thymocyte expansion and predisposes mutant animal to tumorigenesis. Here, we investigate the mechanism by which p16Ink4a controls thymocyte development by analyzing transgenic mice expressing the human p16INK4a into the T cell lineage. We show that forced expression of p16INK4a in thymocytes blocked T cell differentiation at the early CD4−CD8−CD3−CD25+ stage without significantly affecting the development of γδ T cells. Pre-TCR function was mimicked by the induction of CD3 signaling in thymocytes of recombinase activating gene (RAG)-2-deficient mice (RAG-2−/−). Upon anti-CD3ε treatment in vivo, p16INK4a-expressing RAG-2−/− thymocytes were not rescued from apoptosis, nor could they differentiate. Our data demonstrate that expression of p16INK4a prevents the pre-TCR-mediated expansion and/or survival of differentiating thymocytes.
Dendritic Cells Transduced with Protein Antigens Induce Cytotoxic Lymphocytes and Elicit Antitumor Immunity
Authors: Shibagaki Naotaka , Udey Mark C. 
Published: April 2014

Abstract
Dendritic cell (DC)-based vaccines are being developed for treatment of patients with cancer, in part because DC are potent inducers of CD8+ CTL. DC MHC class I:antigenic peptide complexes that are required for CTL elicitation are most often generated by incubating DC with peptides or by transfecting (or transducing) DC with cDNAs (or viral vectors) that encode protein Ags. The former approach is feasible when MHC class I Ags and relevant peptides are known. The latter approach may be hampered by inefficient DC transfection (transduction) and/or difficulties associated with preparation and use of viral vectors. Herein we demonstrate that a bacterial recombinant model tumor-associated Ag (OVA) that contains the HIV TAT protein transduction domain (PTD) was readily engineered and purified, efficiently transduced murine lymphocytes and DC, and was processed by proteasomes for MHC class I-restricted presentation to CTL. In addition, PTD-containing rOVA was processed and presented by DC to CD4 T cells as efficiently as native OVA or rOVA lacking the PTD. PTD-OVA-transduced DC induced CTL in vivo in a Th cell-independent fashion and vaccinated against OVA-expressing tumors. In contrast, rOVA lacking the PTD did not enter the DC MHC class I presentation pathway and DC treated with this protein did not prime OVA-specific CTL in vivo. Treatment of mice harboring clinically apparent OVA-expressing tumors with PTD-OVA-transduced DC resulted in tumor regression in some animals. This straightforward vaccination strategy may translate into DC-based treatments for patients with cancer and other serious diseases.
Response toNeisseria gonorrhoeaeby Cervicovaginal Epithelial Cells Occurs in the Absence of Toll-Like Receptor 4-Mediated Signaling
Authors: Fichorova Raina N. , Cronin Amanda O. , Lien Egil , Anderson Deborah J. , Ingalls Robin R. 
Published: April 2014

AbstractToll-like receptors (TLRs) have recently been identified as fundamental components of the innate immune response to bacterial pathogens. We investigated the role of TLR signaling in immune defense of the mucosal epithelial cells of the lower female genital tract. This site provides first line defense against microbial pathogens while remaining tolerant to a complex biosystem of resident microbiota. Epithelial cells derived from normal human vagina, ectocervix, and endocervix expressed mRNA for TLR1, -2, -3, -5, and -6. However, they failed to express TLR4 as well as MD2, two essential components of the receptor complex for LPS in phagocytes and endothelial cells. Consistent with this, endocervical epithelial cells were unresponsive to protein-free preparations of lipooligosaccharide from Neisseria gonorrhoeae and LPS from Escherichia coli. However, they were capable of responding to whole Gram-negative bacteria and bacterial lysates, as demonstrated by NF-κB activation and proinflammatory cytokine production. The presence of soluble CD14, a high-affinity receptor for LPS and other bacterial ligands, enhanced the sensitivity of genital tract epithelial cells to both low and high concentrations of bacteria, suggesting that soluble CD14 can act as a coreceptor for non-TLR4 ligands. These data demonstrate that the response to N. gonorrhoeae and other Gram-negative bacteria at the mucosal surface of the female genital tract occurs in the absence of endotoxin recognition and TLR4-mediated signaling.
Cooperation of C1q Receptors and Integrins in C1q-Mediated Endothelial Cell Adhesion and Spreading
Authors: Feng Xiaodong , Tonnesen Marcia G. , Peerschke Ellinor I. B. , Ghebrehiwet Berhane 
Published: April 2014

Abstract
The interaction of C1q with endothelial cells elicits a multiplicity of biologic responses. Although these responses are presumed to be mediated by the interaction of C1q with endothelial cell surface proteins, the identity of the participants is not known. In this study we examined the roles of two C1q binding proteins, cC1q-R/calreticulin and gC1q-R/p33, in C1q-mediated adhesion and spreading of human dermal microvascular endothelial cells (HDMVEC). When HDMVEC were cultured in microtiter plate wells coated with concentrations of C1q ranging from 0 to 50 μg/ml, a specific and dose-dependent adhesion and spreading was observed. The extent of adhesion and spreading was similar to the adhesion seen on collagen-coated wells. Spreading (68 ± 12%) and to a moderate extent adhesion (47 ± 9%) were inhibited by anti-gC1q-R mAb 60.11. Similar effects were noted with polyclonal anti-cC1q-R but not with control nonimmune IgG. The two Abs had a slight additive effect (75 ± 13% inhibition) when mixed together in the proportion of 100 μg/ml anti-gC1q-R and 30 μg/ml anti-cC1q-R. More importantly, a 100% inhibition of spreading, but not adhesion, to C1q-coated wells was observed when HDMVEC were cultured in the presence of 30 μM of the peptide GRRGDSP but not GRRGESP. Furthermore, while anti-β1 integrin Ab blocked both adhesion and spreading, anti-α5 integrin blocked only spreading and not adhesion. Ag capture ELISA of endothelial cell membrane proteins using polyclonal anti-gC1q-R showed the presence of not only β1 and α5 integrins but also CD44. Taken together these results suggest that endothelial cell adhesion and spreading require the cooperation of both C1qRs and β1 integrins and possibly other membrane-spanning molecules.
IL-4 Pretreatment Selectively Enhances Cytokine and Chemokine Production in Lipopolysaccharide-Stimulated Mouse Peritoneal Macrophages
Authors: Major Jennifer , Fletcher Julia E. , Hamilton Thomas A. 
Published: April 2014

Abstract
Although well recognized for its anti-inflammatory effect on gene expression in stimulated monocytes and macrophages, IL-4 is a pleiotropic cytokine that has also been shown to enhance TNF-α and IL-12 production in response to stimulation with LPS. In the present study we expand these prior studies in three areas. First, the potentiating effect of IL-4 pretreatment is both stimulus and gene selective. Pretreatment of mouse macrophages with IL-4 for a minimum of 6 h produces a 2- to 4-fold enhancement of LPS-induced expression of several cytokines and chemokines, including TNF-α, IL-1α, macrophage-inflammatory protein-2, and KC, but inhibits the production of IL-12p40. In addition, the production of TNF-α by macrophages stimulated with IFN-γ and IL-2 is inhibited by IL-4 pretreatment, while responses to both LPS and dsRNA are enhanced. Second, the ability of IL-4 to potentiate LPS-stimulated cytokine production appears to require new IL-4-stimulated gene expression, because it is time dependent, requires the activation of STAT6, and is blocked by the reversible protein synthesis inhibitor cycloheximide during the IL-4 pretreatment period. Finally, IL-4-mediated potentiation of TNF-α production involves specific enhancement of mRNA translation. Although TNF-α protein is increased in IL-4-pretreated cells, the level of mRNA remains unchanged. Furthermore, LPS-stimulated TNF-α mRNA is selectively enriched in actively translating large polyribosomes in IL-4-pretreated cells compared with cells stimulated with LPS alone.
Airway Hyperresponsiveness, Late Allergic Response, and Eosinophilia Are Reversed with Mycobacterial Antigens in Ovalbumin-Presensitized Mice
Authors: Hopfenspirger Michael T. , Agrawal Devendra K. 
Published: April 2014

AbstractPretreatment with mycobacterial Ags has been shown to be effective in preventing allergic airway inflammation from occurring in a mouse model. Because most asthmatics are treated after the development of asthma, it is crucial to determine whether mycobacterial Ags can reverse established allergic airway inflammation in the presensitized state. Our hypothesis, based upon our previous findings, is that mycobacteria treatment in presensitized mice will suppress the allergic airway inflammation with associated clinical correlates of established asthma, with the noted exception of factors associated with the early allergic response (EAR). BALB/c mice sensitized and challenged with OVA were evaluated for pulmonary functions during both the EAR and late allergic response, and airway hyperresponsiveness to methacholine. Following this, sensitized mice were randomized and treated with placebo or a single dose (1 × 105 CFUs) of bacillus Calmette-Guérin (BCG) or Mycobacterium vaccae via nasal or peritoneal injection. One week later, the mice were rechallenged with OVA and methacholine, followed by bronchoalveolar lavage (BAL) and tissue collection. Mice treated with intranasal BCG were most significantly protected from the late allergic response (p &lt; 0.02), airway hypersensitivity (p &lt; 0.001) and hyperreactivity (p &lt; 0.05) to methacholine, BAL (p &lt; 0.05) and peribronchial (p &lt; 0.01) eosinophilia, and BAL fluid IL-5 levels (p &lt; 0.01) as compared with vehicle-treated, sensitized controls. Intranasal M. vaccae treatment was less effective, suppressing airway hypersensitivity (p &lt; 0.01) and BAL eosinophilia (p &lt; 0.05). No changes were observed in the EAR, BAL fluid IL-4 levels, or serum total and Ag-specific IgE. These data suggest that mycobacterial Ags (BCG≫M. vaccae) are effective in attenuating allergic airway inflammation and associated changes in pulmonary functions in an allergen-presensitized state.
Naturally Processed Chromatin Peptides Reveal a Major Autoepitope That Primes Pathogenic T and B Cells of Lupus
Authors: Kaliyaperumal Arunan , Michaels Marissa A. , Datta Syamal K. 
Published: April 2014

Abstract
Major autoepitopes for pathogenic Th cells of lupus were previously found in core histones of nucleosomes by testing overlapping synthetic peptides. To detect other dominant epitopes, we eluted peptides from MHC class II molecules of a murine lupus APC line that was fed with crude chromatin. The eluted peptides were purified by reverse-phase HPLC and tested for their ability to stimulate autoimmune Th clones, and then analyzed by mass spectrometry. Amino acid sequences of stimulatory fractions revealed three new autoepitopes. Two of the epitopes were homologous to brain transcription factor BRN-3, whereas the third sequence was homologous to histone H1′22–42. H1′22–42 stimulated autoimmune Th cells to augment the production of pathogenic antinuclear Abs, and was much more potent than other nucleosomal epitopes in accelerating glomerulonephritis in lupus-prone (SWR × NZB)F1 (SNF1) mice. Remarkably, a marked expansion of Th1 cells recognizing the H1′22–42 epitope occurred spontaneously in SNF1 mice very early in life. A significant proportion of H1′22–42-specific T cell clones cross-reacted with one or more core histone epitopes, but not with epitopes in other lupus autoantigens. The H1′22–42 epitope was also recognized by autoimmune B cells, and with the onset of lupus nephritis, serum autoantibodies to the H1′22–42 epitope become increasingly cross-reactive with nuclear autoantigens. Convergence of T and B cell epitopes in H1′22–42 and its ability to elicit a cross-reactive response make it a highly dominant epitope that could be targeted for therapy and for tracking autoimmune T and B cells.
Adhesion-Mediated Intracellular Redistribution of c-Fas-Associated Death Domain-Like IL-1-Converting Enzyme-Like Inhibitory Protein-Long Confers Resistance to CD95-Induced Apoptosis in Hematopoietic Cancer Cell Lines
Authors: Shain Kenneth H. , Landowski Terry H. , Dalton William S. 
Published: April 2014

Abstract
Evasion of immune surveillance is a key step in malignant progression. Interactions between transformed hematopoietic cells and their environment may initiate events that confer resistance to apoptosis and facilitate immune evasion. In this report, we demonstrate that β1 integrin-mediated adhesion to fibronectin inhibits CD95-induced caspase-8 activation and apoptosis in hematologic tumor cell lines. This adhesion-dependent inhibition of CD95-mediated apoptosis correlated with enhanced c-Fas-associated death domain-like IL-1-converting enzyme-like inhibitory protein-long (c-FLIPL) cytosolic solubility compared with nonadhered cells. Cytosolic c-FLIPL protein preferentially associated with cytosolic Fas-associated death domain protein (FADD) and localized to the death-inducing signal complex after CD95 ligation in adherent cells. The incorporation of c-FLIPL in the death-inducing signal complex prevented procaspase-8 processing and activation of the effector phase of apoptosis. Adhesion to fibronectin increased c-FLIPL cytosolic solubility and availability for FADD binding by redistributing c-FLIPL from a preexisting membrane-associated fraction. Increased cytosolic availability of c-FLIPL for FADD binding was not related to increased levels of RNA or protein synthesis. These data show that adhesion of anchorage-independent cells to fibronectin provides a novel mechanism of resistance to CD95-mediated programmed cell death by regulating the cellular localization and availability of c-FLIPL.
Thiol Antioxidants Inhibit the Adjuvant Effects of Aerosolized Diesel Exhaust Particles in a Murine Model for Ovalbumin Sensitization
Authors: Whitekus Michael J. , Li Ning , Zhang Min , Wang Meiying , Horwitz Marcus A. , Nelson Sally K. , Horwitz Lawrence D. , Brechun Nicholas , Diaz-Sanchez David , Nel Andre E. 
Published: April 2014

Abstract
Although several epidemiological studies indicate a correlation between exposure to ambient particulate matter and adverse health effects in humans, there is still a fundamental lack of understanding of the mechanisms involved. We set out to test the hypothesis that reactive oxygen species are involved in the adjuvant effects of diesel exhaust particles (DEP) in a murine OVA sensitization model. First, we tested six different antioxidants, N-acetylcysteine (NAC), bucillamine (BUC), silibinin, luteolin, trolox (vitamin E), and ascorbic acid, for their ability to interfere in DEP-mediated oxidative stress in vitro. Of the six agents tested, only the thiol antioxidants, BUC and NAC, were effective at preventing a decrease in intracellular reduced glutathione:glutathione disulfide ratios, protecting cells from protein and lipid oxidation, and preventing heme oxygenase 1 expression. Therefore, we selected the thiol antioxidants for testing in the murine OVA inhalation sensitization model. Our data demonstrate that NAC and BUC effectively inhibited the adjuvant effects of DEP in the induction of OVA-specific IgE and IgG1 production. Furthermore, NAC and BUC prevented the generation of lipid peroxidation and protein oxidation in the lungs of OVA- plus DEP-exposed animals. These findings indicate that NAC and BUC are capable of preventing the adjuvant effects of inhaled DEP and suggest that oxidative stress is a key mechanistic component in the adjuvant effect of DEP. Antioxidant treatment strategies may therefore serve to alleviate allergic inflammation and may provide a rational basis for treating the contribution of particulate matter to asthmatic disease.
In Vivo Triggering Through 4-1BB Enables Th-Independent Priming of CTL in the Presence of an Intact CD28 Costimulatory Pathway
Authors: Diehl Linda , van Mierlo Geertje J. D. , den Boer Annemieke T. , van der Voort Ellen , Fransen Marieke , van Bostelen Liesbeth , Krimpenfort Paul , Melief Cornelis J. M. , Mittler Robert , Toes Rene E. M. , Offringa Rienk 
Published: April 2014

AbstractTriggering of 4-1BB, a member of the TNFR family, through in vivo administration of agonistic anti-4-1BB Ab delivers a powerful costimulatory signal to CTL. We found this signal to effectively replace the need for CD4+ T cell help in the cross-priming of tumor-specific CTL immunity. Furthermore, 4-1BB Ab can convert an otherwise tolerogenic peptide vaccine into a formulation capable of efficient CTL priming. Initial activation of naive CTL can occur in the absence of 4-1BB costimulation, but this signal permits increased survival of Ag-stimulated CTL. Because naive CTL do not express 4-1BB at their surface, susceptibility to 4-1BB triggering depends on prior up-regulation of this receptor. We show that this requires both stimulation of the TCR and CD28-dependent costimulation. Accordingly, blockade of the CD28-costimulatory pathway abrogates the capacity of agonistic anti-4-1BB Ab to trigger Th-independent CTL immunity. In conclusion, our data reveal that the 4-1BB-mediated survival signal is positioned downstream of Ag-specific TCR triggering and CD28-dependent costimulation of naive CTL. The powerful effects of 4-1BB triggering on the induction, amplification, and persistence of CTL responses provide a novel strategy for increasing the potency of vaccines against cancers.
During Differentiation of the Monocytic Cell Line U937, Purα Mediates Induction of theCD11cβ2 Integrin Gene Promoter
Authors: Shelley C. Simon , Teodoridis Jens M. , Park Heiyoung , Farokhzad Omid C. , Böttinger Erwin P. , Arnaout M. Amin 
Published: April 2014

AbstractCD11c is a member of the β2 integrin family of adhesion molecules that, together with CD18, forms a heterodimeric receptor on the surface of myeloid, NK, dendritic, and certain leukemic, lymphoma, and activated lymphoid cells. Monocytic differentiation is associated with an induction of both CD11c and CD18 gene expression. The resulting CD11c/CD18 receptor mediates firm adhesion to the vascular endothelium, transendothelial migration, chemotaxis, and phagocytosis. Monocytic differentiation can be mimicked in vitro by treatment of the promonocytic cell line U937 with PMA. Recently, we reported that in U937 cells, expression of the CD11c gene is controlled by an unidentified transcription factor that binds ssDNA. This finding suggested that DNA secondary structure plays an important role in controlling the CD11c gene and prompted us to search for additional ssDNA-binding activities with which this gene interacts. In this study, we report that in U937 cells, expression of the CD11c gene is mediated by the ssDNA-binding protein Purα. During PMA-induced differentiation, the ability of Purα to activate the CD11c promoter in U937 cells increases, as does that of Sp1. Together, these increases in the functional activity of both Purα and Sp1 combine to induce CD11c expression.
Immunization with a Recombinant Adenovirus Encoding a Lymphoma Idiotype: Induction of Tumor-Protective Immunity and Identification of an Idiotype-Specific T Cell Epitope
Authors: Armstrong Anne C. , Dermime Said , Allinson Christopher G. , Bhattacharyya Tapan , Mulryan Kate , Gonzalez Karin R. , Stern Peter L. , Hawkins Robert E. 
Published: April 2014

AbstractThe Ig Id of a B cell lymphoma is a tumor-specific Ag, although as a self-Ag it is likely to be a weak immunogen. Provision of a foreign gene may enhance the immunogenicity of the idiotype. Viral vectors allow highly efficient transfer of genetic material and are themselves innately immunogenic. We have investigated the ability of recombinant adenoviral vectors, encoding the idiotypic gene with or without fusion to the human Fc region, to produce anti-idiotypic Ab- and T cell-mediated responses in a syngeneic BALB/c A20 murine lymphoma model. The idiotypic VH and VL sequences were assembled as a single chain variable fragment (scFv) and adenoviral vectors encoding the A20 scFv (Ad.A20) and A20 scFv linked to the Fc fragment of human IgG1 (Ad.A20hFc) were constructed. A single immunization of BALB/c mice with Ad.A20hFc but not Ad.A20 induced a specific anti-idiotypic Ab response. T cell lines generated from mice vaccinated with either vector displayed specific cytotoxicity, proliferation, and IFN-γ release against a syngeneic dendritic cell line transduced using a retroviral vector to express the A20 scFv idiotype (XS52.A1.A20). Importantly, both T cell lines lysed the A20 lymphoma cells. An immunodominant H-2Kd-restricted CD8+ T cell peptide, DYWGQGTEL (A20[106–114]), was identified as a naturally occurring A20 scFv epitope. A single immunization with Ad.A20hFc but not Ad.A20 provided protection in &gt;40% of animals challenged with a lethal dose of the A20 tumor line and was more effective, in this model, than a previously optimized plasmid vaccine.