bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Soluble Factor Produced by Lamina Propria Mononuclear Cells Is Required for TNF-α Enhancement of IFN-γ Production by T Cells
Authors: Prehn John L. , Landers Carol J. , Targan Stephan R. 
Published: December 2022

AbstractThe role of TNF-α in the mucosal inflammation of Crohn’s disease has been demonstrated by the prolonged clinical responses and/or remissions among patients receiving i.v. infusion of anti-TNF-α. A correlation between TNF-α and elevated IFN-γ production is suggested by the reduction in the number of IFN-γ producing lamina propria mononuclear cells (LPMC) found in colonic biopsies from anti-TNF-α-treated patients. The aim of this study was to define the mechanism of TNF-α-augmented mucosal T cell IFN-γ production. In this paper we present evidence that cultured LPMC secrete a factor which acts on preactivated T cells in concert with TNF-α to augment IFN-γ production. This activity is independent of IL-12 and IL-18, the well-documented potentiators of IFN-γ expression, and is not produced by PBMC. Peripheral blood PHA-activated T cells incubated in supernatants from LPMC became responsive to TNF-α by increasing IFN-γ output upon stimulation. These results are consistent with a model in which LPMC, but not PBMC, release an unidentified substance when cultured in vitro with low dose IL-2. This substance can act on preactivated peripheral T cells, as well as on lamina propria T cells, conditioning them to respond to TNF-α by increased IFN-γ secretion upon stimulation. Expression of this factor in the gut mucosa could contribute to up-regulation of the Th1 response in the presence of TNF-α, and could be important for mucosal immunoregulation.
Inhibition of CD28 Expression by Oligonucleotide Decoys to the Regulatory Element in Exon 1 of the CD28 Gene
Authors: Tam Robert C. , Lin Catherine J. , Lim Charmaine , Pai Bharati , Stoisavljevic Vesna 
Published: December 2022

Abstract
Ligation of CD28 provides a costimulatory signal essential for Ag-mediated T cell activation via the TCR. Previously we demonstrated that inhibition of human and murine CD28 expression by a guanosine (G)-rich oligonucleotide (ODN), GR1, led to immunosuppression in vitro and in vivo. The bioactivity of GR1 was dependent on a G-rich DNA sequence motif consisting of two G tetrads separated by four nucleotides, (G4N4G4). We have shown recently that a G-rich region, designated CD28GR, in exon 1 of the CD28 gene is such a motif and is a positive regulatory element that binds the transcription factors Sp1 and EGR-1. Here we showed that the bioactivity of GR1 and the related GR2 correlated with the sequence-specific formation of distinct nuclear protein complexes and a high degree of ODN secondary structure. In addition, these ODN blocked transcription factor binding to CD28GR (also in a sequence-specific manner) and prevented CD28GR from driving transcription of a reporter gene. Interestingly, GR1 potently inhibited CD28, but not the expression of other Sp1- and EGR-1-regulated genes, an effect associated with lower Sp1 protein binding affinity of GR1 and GR2 compared with that of canonical Sp1 sites. These data show that DNA sequences that contain the G-rich sequence motif, G4N4G4, such as GR1 and GR2, can functionally mimic the regulatory protein binding ability of CD28GR. Thus, GR1 and GR2 act as molecular decoys to selectively interfere with transcriptional regulation of the CD28 gene.
Cerebral Endothelial Cells Release TNF-α After Stimulation with Cell Walls of Streptococcus pneumoniae and Regulate Inducible Nitric Oxide Synthase and ICAM-1 Expression Via Autocrine Loops
Authors: Freyer Dorette , Manz Rahel , Ziegenhorn Andreas , Weih Markus , Angstwurm Klemens , Döcke Wolf-Dietrich , Meisel Andreas , Schumann Ralf R. , Schönfelder Gilbert , Dirnagl Ulrich , Weber Joerg R. 
Published: December 2022

Abstract
TNF-α, inducible NO synthase (iNOS), and ICAM-1 are considered to be key proteins in the inflammatory response of most tissues. We tested the hypothesis that cell walls of Streptococcus pneumoniae (PCW), the most common cause of adult bacterial meningitis, induce TNF-α, iNOS, and ICAM-1 expression in rat primary brain microvascular endothelial cell cultures. We detected TNF-α mRNA by RT-PCR already 1 h after stimulation with PCW, while TNF-α protein peaked at 4 h (9.4 ± 3.6 vs 0.1 ± 0.1 pg/μg protein). PCW induced iNOS mRNA 2 h after stimulation, followed by an increase of the NO degradation product nitrite (18.1 ± 4 vs 5.8 ± 1.8 at 12 h; 18.1 ± 4 vs 5.8 ± 1.8 pmol/μg protein at 72 h). The addition of TNF-α Ab significantly reduced nitrite production to 62.2 ± 14.4% compared with PCW-stimulated brain microvascular endothelial cells (100%). PCW induced the expression of ICAM-1 (measured by FACS), which was completely blocked by TNF-α Ab (142 ± 18.6 vs 97.5 ± 12.4%; 100% unstimulated brain microvascular endothelial cells). Cerebral endothelial cells express TNF-α mRNA as well as iNOS mRNA and release the bioactive proteins in response to PCW. PCW-induced NO production is mediated in part by an autocrine pathway involving TNF-α, whereas ICAM-1 expression is completely mediated by this autocrine loop. By these mechanisms, cerebral endothelial cells may regulate critical steps in inflammatory blood-brain-barrier disruption of bacterial meningitis.
Specificity of CTL Interactions with Peptide-MHC Class I Tetrameric Complexes Is Temperature Dependent
Authors: Whelan Joseph A. , Dunbar P. Rod , Price David A. , Purbhoo Marco A. , Lechner Franziska , Ogg Graham S. , Griffiths Gillian , Phillips Rodney E. , Cerundolo Vincenzo , Sewell Andrew K. 
Published: December 2022

AbstractTetrameric peptide-MHC class I complexes (“tetramers”) are proving invaluable as reagents for characterizing immune responses involving CTLs. However, because the TCR can exhibit a degree of promiscuity for binding peptide-MHC class I ligands, there is potential for cross-reactivity. Recent reports showing that the TCR/peptide-MHC interaction is dramatically dependent upon temperature led us to investigate the effects of incubation temperature on tetramer staining. We find that tetramers rapidly stain CTLs with high intensity at 37°C. We examine the fine specificity of tetramer staining using a well-characterized set of natural epitope variants. Peptide variants that elicit little or no functional cellular response from CTLs can stain these cells at 4°C but not at 37°C when incorporated into tetramers. These results suggest that some studies reporting tetramer incubations at 4°C could detect cross-reactive populations of CTLs with minimal avidity for the tetramer peptide, especially in the tetramer-low population. For identifying specific CTLs among polyclonal cell populations such as PBLs, incubation with tetramers at 37°C improves the staining intensity of specific CTLs, resulting in improved separation of tetramer-high CD8+ cells. Confocal microscopy reveals that tetramers incubated at 37°C can be rapidly internalized by specific CTLs into vesicles that overlap with the early endocytic compartment. This TCR-specific internalization suggests that coupling of tetramers or analogues with toxins, which are activated only after receptor internalization, may create immunotoxins capable of killing CTLs of single specificities.
The Epithelial Cell Response to Rotavirus Infection
Authors: Rollo Ellen E. , Kumar K. Prasanna , Reich Nancy C. , Cohen Jean , Angel Juana , Greenberg Harry B. , Sheth Riten , Anderson Joseph , Oh Brian , Hempson Scott J. , Mackow Erich R. , Shaw Robert D. 
Published: December 2022

AbstractRotavirus is the most important worldwide cause of severe gastroenteritis in infants and young children. Intestinal epithelial cells are the principal targets of rotavirus infection, but the response of enterocytes to rotavirus infection is largely unknown. We determined that rotavirus infection of HT-29 intestinal epithelial cells results in prompt activation of NF-κB (&lt;2 h), STAT1, and ISG F3 (3 h). Genetically inactivated rotavirus and virus-like particles assembled from baculovirus-expressed viral proteins also activated NF-κB. Rotavirus infection of HT-29 cells induced mRNA for several C-C and C-X-C chemokines as well as IFNs and GM-CSF. Mice infected with simian rotavirus or murine rotavirus responded similarly with the enhanced expression of a profile of C-C and C-X-C chemokines. The rotavirus-stimulated increase in chemokine mRNA was undiminished in mice lacking mast cells or lymphocytes. Rotavirus induced chemokines only in mice &lt;15 days of age despite documented infection in older mice. Macrophage inflammatory protein-1β and IFN-stimulated protein 10 mRNA responses occurred, but were reduced in p50−/− mice. Macrophage inflammatory protein-1β expression during rotavirus infection localized to the intestinal epithelial cell in murine intestine. These results show that the intestinal epithelial cell is an active component of the host response to rotavirus infection.
The NF-κB Family Member RelB Is Required for Innate and Adaptive Immunity toToxoplasma gondii
Authors: Caamaño Jorge , Alexander James , Craig Linden , Bravo Rodrigo , Hunter Christopher A. 
Published: December 2022

AbstractThe NF-κB family of transcription factors are associated with the regulation of innate and adaptive immunity to infection. Infection of C57BL/6 mice with Toxoplasma gondii resulted in up-regulation of NF-κB activity that included the NF-κB family member RelB. To assess the role of RelB in the regulation of the immune response to this infection, we challenged RelB-deficient mice (RelB−/−) and wild-type (WT) littermate controls with T. gondii. Although WT controls were resistant to T. gondii, RelB−/− mice succumbed 10–15 days after infection. Examination of accessory cell functions associated with resistance to T. gondii revealed that RelB−/− macrophages stimulated with IFN-γ plus LPS or TNF-α produced IL-12 as well as reactive nitrogen intermediates and inhibited parasite replication similar to WT macrophages. Analysis of the systemic responses of RelB−/− and WT mice revealed that infected mice had similar serum levels of IL-12. However, RelB−/− mice challenged with T. gondii produced negligible levels of IFN-γ and had reduced NK cell activity compared with WT mice. Similarly, splenocytes from uninfected RelB−/− mice stimulated with polyclonal stimuli were deficient in their ability to produce IFN-γ. Together, our results demonstrate that RelB is essential for the development of innate NK and adaptive T cell responses that lead to the production of IFN-γ and resistance to T. gondii.
Nitric Oxide Participates in the Recovery of Normal Jejunal Epithelial Ion Transport Following Exposure to the Superantigen,Staphylococcus aureusEnterotoxin B
Authors: McKay Derek M. , Lu Jun , Jedrzkiewicz Sean , Ho Winnie , Sharkey Keith A. 
Published: December 2022

AbstractBacterial superantigens (SAgs) are potent T cell activators. Mice treated 4 h previously with the SAg, Staphylococcus aureus enterotoxin B (SEB), display reduced ion transport (assessed by short circuit current) responses to prosecretory stimuli, which normalize 24 h posttreatment. Here, mice were treated with SEB alone or in combination with an inhibitor of the inducible form of NO synthase (iNOS), l-NIL. Subsequently, jejunal iNOS expression was detected by immunohistochemistry, ion transport was evaluated in Ussing chambers, and serum levels of TNF-α and IFN-γ were measured by ELISA. SEB-treated mice had increased epithelial iNOS immunoreactivity, and numerous iNOS-positive CD3+ T cells occurred in their mucosa and submucosa. Concomitant treatment with l-NIL did not affect the reduced short circuit current responsiveness to electrical nerve stimulation or the prosecretory agents, carbachol and forskolin, that occurred 4 h post-SEB (5 μg) treatment. However, Isc responses in l-NIL- plus SEB-treated mice were still significantly reduced 24 h posttreatment, indicating a role for NO in the restoration of normal ion transport following exposure to SAgs. The prolongation of epithelial ion transport abnormalities correlated with elevated serum levels of TNF-α and IFN-γ in mice treated 24 h previously with l-NIL plus SEB compared with those in controls and SEB-only-treated mice. Additionally, mice treated with l-NIL plus SEB and TNF-α- or IFN-γ-neutralizing Abs displayed normal jejunal ion transport characteristics 24 h posttreatment. We conclude that NO mobilization is important in the homeostatic recovery response following immune stimulation by SAgs and that the beneficial effect of NO in this model system is probably via regulation of TNF-α and IFN-γ production.
Activation of p90RSK and cAMP Response Element Binding Protein in Stimulated Neutrophils: Novel Effects of the Pyridinyl Imidazole SB 203580 on Activation of the Extracellular Signal-Regulated Kinase Cascade
Authors: Lian Jian P. , Huang RiYun , Robinson Dwight , Badwey John A. 
Published: December 2022

AbstractNeutrophils stimulated with the chemoattractant FMLP or the phorbol ester PMA are known to exhibit activation of a 90-kDa renaturable protein kinase. Activation of this kinase was maximal at ∼1–3 min after cell stimulation and the time course for activation was similar to that of the extracellular-regulated kinases (ERKs) and p38-mitogen activated protein kinase (p38MAPK). Compounds that block activation of ERK-1/2 (PD 98059) or that inhibit the activity of p38MAPK (SB 203580) blocked activation of this 90-kDa kinase. SB 203580 is a highly selective inhibitor of p38MAPK in vitro and is under intense study as a lead compound for developing novel anti-inflammatory agents. However, we demonstrate that SB 203580 at concentrations ≥10 μM can also inhibit activation of ERK-1/2 in neutrophils. An Ab to the protein kinase p90RSK2 (also referred to as MAPKAP-K1b, or p90rsk) immunoprecipitated the active 90-kDa kinase from lysates of stimulated neutrophils. No activity was observed for this enzyme in immunoprecipitates obtained from unstimulated cells, and the amounts of activity were markedly reduced if the cells were treated with PD 98059 or SB 203580 before stimulation. Neutrophils stimulated with FMLP exhibited phosphorylation of the cAMP response element binding protein (CREB), and this reaction was inhibited by SB 203580 and PD 98059. These data establish that the renaturable 90-kDa protein kinase is p90RSK2 and that CREB may be a substrate for this enzyme in these cells. Novel effects of compound SB 203580 on stimulated neutrophils are also described.
Posttranscriptional Regulation of Acute Phase Serum Amyloid A2 Expression by the 5′- and 3′-Untranslated Regions of Its mRNA
Authors: Longley Daniel B. , Steel Diana M. , Whitehead Alexander S. 
Published: December 2022

AbstractHuman acute-phase serum amyloid A protein (A-SAA) is a major acute phase reactant, the concentration of which increases dramatically as part of the body’s early response to inflammation. A-SAA is the product of two almost identical genes, SAA1 and SAA2, which are induced by the pro-inflammatory cytokines, IL-1 and IL-6. In this study, we examine the roles played by the 5′- and 3′-untranslated regions (UTRs) of the SAA2 mRNA in regulating A-SAA2 expression. SAA2 promoter-driven luciferase reporter gene constructs carrying the SAA2 5′-UTR and/or 3′-UTR were transiently transfected into the HepG2 human hepatoma cell line. After induction of chimeric mRNA with IL-1β and IL-6, the SAA2 5′- and 3′-UTRs were both able to posttranscriptionally modify the expression of the luciferase reporter. The SAA2 5′-UTR promotes efficient translation of the chimeric luciferase transcripts, whereas the SAA2 3′-UTR shares this property and also significantly accelerates the rate of reporter mRNA degradation. Our data strongly suggest that the SAA2 5′- and 3′-UTRs each play significant independent roles in the posttranscriptional regulation of A-SAA2 protein synthesis.
Adenoviral Vector-Mediated Overexpression of IL-4 in the Knee Joint of Mice with Collagen-Induced Arthritis Prevents Cartilage Destruction
Authors: Lubberts Erik , Joosten Leo A. B. , van den Bersselaar Liduine , Helsen Monique M. A. , Bakker Andrew C. , van Meurs Joyce B. J. , Graham Frank L. , Richards Carl D. , van den Berg Wim B. 
Published: December 2022

AbstractRheumatoid arthritis is a chronic inflammatory joint disease, leading to cartilage and bone destruction. In this study, we investigated the effects of local IL-4 application, introduced by a recombinant human type 5 adenovirus vector, in the knee joint of mice with collagen-induced arthritis. One intraarticular injection with an IL-4-expressing virus caused overexpression of IL-4 in the mouse knee joint. Enhanced onset and aggravation of the synovial inflammation were found in the IL-4 group. However, despite ongoing inflammation, histologic analysis showed impressive prevention of chondrocyte death and cartilage erosion. In line with this, chondrocyte proteoglycan synthesis was enhanced in the articular cartilage. This was quantified with ex vivo 35S-sulfate incorporation in patellar cartilage and confirmed by autoradiography on whole knee joint sections. Reduction of cartilage erosion was further substantiated by lack of expression of the stromelysin-dependent cartilage proteoglycan breakdown neoepitope VDIPEN in the Ad5E1 mIL-4-treated knee joint. Reduced metalloproteinase activity was also supported by markedly diminished mRNA expression of stromelysin-3 in the synovial tissue. Histologic analysis revealed marked reduction of polymorphonuclear cells in the synovial joint space in the IL-4-treated joints. This was confirmed by immunolocalization studies on knee joint sections using NIMP-R14 staining and diminished mRNA expression of macrophage-inflammatory protein-2 in the synovium tissue. mRNA levels of TNF-α and IL-1β were suppressed as well, and IL-1β and nitric oxide production by arthritic synovial tissue were strongly reduced. Our data show an impressive cartilage-protective effect of local IL-4 and underline the feasibility of local gene therapy with this cytokine in arthritis.
Novel Path to Activation of Vascular Smooth Muscle Cells: Up-Regulation of gp130 Creates an Autocrine Activation Loop by IL-6 and Its Soluble Receptor
Authors: Klouche Mariam , Bhakdi Sucharit , Hemmes Monika , Rose-John Stefan 
Published: December 2022

Abstract
This study describes a novel path to the activation of smooth muscle cells (SMC) by the IL-6/soluble IL-6 receptor (sIL-6R) system. Human vascular SMC constitutively express only scant amounts of IL-6R and so do not respond to stimulation with this cytokine. We show that SMC also do not constitutively express appreciable levels of gp130, which would render them sensitive to transsignaling by the IL-6/sIL-6R complex. Because gp130 is generally believed not to be subject to regulation, SMC would thus appear not to qualify as targets for the IL-6/sIL-6R system. However, we report that treatment of SMC with IL-6/sIL-6R provokes marked up-regulation of gp130 mRNA and surface protein expression. This is accompanied by secretion of IL-6 by the cells, so that an autocrine stimulation loop is created. In the wake of this self-sustaining system, there is a selective induction and secretion of MCP-1, up-regulation of ICAM-1, and marked cell proliferation. The study identifies SMC as the first example of cells in which gp130 expression is subject to substantive up-regulation, and discovers a novel amplification loop involving IL-6 and its soluble receptor that drives SMC into a proinflammatory state.
Nephritogenic λ Light Chain Dimer: A Unique Human Miniautoantibody Against Complement Factor H
Authors: Jokiranta T. Sakari , Solomon Alan , Pangburn Michael K. , Zipfel Peter F. , Meri Seppo 
Published: December 2022

Abstract
A unique monoclonal Ig λ light chain dimer (protein LOI) was isolated from the serum and urine of a patient with hypocomplementemic membranoproliferative glomerulonephritis. In vitro the λ light chain dimer efficiently activated the alternative pathway of complement (AP). When added to normal human serum, LOI temporarily enhanced AP hemolytic activity, but during a prolonged incubation the hemolytic activity was depleted. Protein LOI was found to bind to factor H, the main regulator molecule of AP. By binding to the short consensus repeat domain 3 of factor H, the dimer LOI blocked one of three interaction sites between H and C3b and thus inhibited the activity of H and induced an uncontrolled activation of the AP. Structural analysis showed that LOI belonged to the Vλ3a subgroup of λ light chains. The variable (V) region of LOI was most closely related to the predicted product of the Vλ3 germline gene Iglv3s2, although it contained several unique residues that in a tertiary homology model structure form an unusual ring of charged residues around a hydrophobic groove in the putative Ag binding site. This site fitted considerably well with a putative binding site in the molecular model of domain 3 of factor H containing a reciprocal ring of charged amino acids around a hydrophobic area. Apparently, functional blocking of factor H by the Ab fragment-like λ light chain dimer had initiated the development of a severe form of membranoproliferative glomerulonephritis. Thus, the λ light chain dimer LOI represents the first described pathogenic miniautoantibody in human disease.
Switching to IgG3, IgG2b, and IgA Is Division Linked and Independent, Revealing a Stochastic Framework for Describing Differentiation
Authors: Deenick Elissa K. , Hasbold Jhagvaral , Hodgkin Philip D. 
Published: December 2022

AbstractLPS was used to induce switching of B cells to IgG3 and, in the presence of TGF-β, to IgG2b and IgA. Switching to all three isotypes increased with division number according to a consistent relationship that was independent of time in culture. The mode of activation altered the relationship with division, as CD40 ligand increased switching to IgA and decreased switching to IgG2b and IgG3 when measured per division. This division-linked switching behavior could be described by Gaussian probability distributions centered around a mean division number. The divisions at which switching to IgG3 and IgG2b occurred overlapped, raising the possibility that the two switching mechanisms were linked. However, when IgG3+ and IgG3− B cells were sorted and placed back in culture, they switched to IgG2b at an equivalent rate, indicating that alternative switching decisions were made independently within a single cell. As a consequence, isotype switching could be predicted at the population level by standard probability laws. Therefore, division number provides a framework for a stochastic description of differentiation that may be widely applicable.
Protein Kinase C Inhibits CD95 (Fas/APO-1)-Mediated Apoptosis by at Least Two Different Mechanisms in Jurkat T Cells
Authors: Ruiz-Ruiz Carmen , Robledo Gema , Font Jovita , Izquierdo Manuel , López-Rivas Abelardo 
Published: December 2022

AbstractWe have recently reported that activation of protein kinase C (PKC) plays a negative role in CD95-mediated apoptosis in human T cell lines. Here we present data indicating that although the PKC-induced mitogen-activated protein kinase pathway could be partially implicated in the abrogation of CD95-mediated apoptosis by phorbol esters in Jurkat T cells, the major inhibitory effect is exerted through a PKC-dependent, mitogen-activated protein kinase-independent signaling pathway. Furthermore, we demonstrate that activation of PKC diminishes CD95 receptor aggregation elicited by agonistic CD95 Abs. On the other hand, it has been reported that UV radiation-induced apoptosis is mediated at least in part by the induction of CD95 oligomerization at the cell surface. Here we show that activation of PKC also inhibits UVB light-induced CD95 aggregation and apoptosis in Jurkat T cells. These results reveal a novel mechanism by which T cells may restrain their sensitivity to CD95-induced cell death through PKC-mediated regulation of CD95 receptor oligomerization at the cell membrane.