bluuebunny/crossref_metadata_2025_split huggingface dataset:
CD40 Ligand Is Pivotal to Efficient Control of Virus Replication in Mice Infected with Lymphocytic Choriomeningitis Virus
Authors: Thomsen A. Randrup , Nansen A. , Christensen J. Pravsgaard , Andreasen S. Ørding , Marker O. 
Published: December 2022

Abstract
CD40 ligand (CD40L) is an important molecule that is known to be involved in T-B collaboration and certain aspects of cell-mediated immunity. However, its role in antiviral immunity has not been clearly defined as of yet. Therefore, mice with a targeted defect in the gene encoding this molecule were infected with one of two strains of lymphocytic choriomeningitis virus differing markedly in their capacity to spread in the host. Infection with lymphocytic choriomeningitis virus is initially controlled primarily by CD8+ effector cells, whereas long-term immune surveillance also depends upon CD4+ cells and B cells. Our results reveal that the primary activation, clonal expansion, and differentiation of CD8+ T cells does not require expression of CD40L. However, lack of expression results in rapid impairment of CTL responsiveness and failure to permanently control virus replication. This happens not only in mice infected with the rapidly spreading virus strain but also at a late stage in mice infected with the strain of more limited potential for spreading. In the latter mice, virus replication is initially controlled very efficiently, but high levels of virus can be detected in the blood and internal organs ∼6 mo after virus inoculation. Since the impairment of immune function seems to be more pronounced in CD40L-deficient mice than in mice lacking either CD4+ cells or B cells, these results indicate that CD40L is pivotal to sustain efficient antiviral immune surveillance, including CD8+ T cells, and suggest that CD40L is critically involved in cellular interactions in addition to T-B cooperation.
Differential Requirements for ZAP-70 in TCR Signaling and T Cell Development
Authors: Kadlecek Theresa A. , van Oers Nicolai S. C. , Lefrancois Leo , Olson Sara , Finlay Deborah , Chu David H. , Connolly Kari , Killeen Nigel , Weiss Arthur 
Published: December 2022

AbstractThe Syk/ZAP-70 family of protein tyrosine kinases is indispensable for normal lymphoid development. Syk is necessary for the development of B cells and epithelial γδ T cells, whereas ZAP-70 is essential for the normal development of T cells and TCR signaling. In this study, we show that although development of the αβ lineage was arrested in the thymus, CD3-positive T cells, primarily of the γδ lineage, were present in the lymph nodes of mice lacking ZAP-70. Moreover, in the absence of ZAP-70, dendritic epidermal T cells were fewer in number and of abnormal morphology, and intestinal intraepithelial lymphocytes, normally containing a large proportion of γδ T cells, were markedly reduced. These data suggest that γδ T cells show a variable dependence upon ZAP-70 for their development. Biochemical analyses of thymocytes revealed a lack of basal ζ-chain tyrosine phosphorylation. However, several other substrates were inducibly tyrosine phosphorylated following TCR stimulation. Thus, TCR-mediated signaling in ZAP-70-deficient thymocytes is only partially impaired. These studies suggest that Syk compensates only partially for the loss of ZAP-70, and that there is an absolute requirement of ZAP-70 for αβ T cells and epithelial γδ T cells, but not for some γδ T cells in peripheral lymphoid tissues.
p48/STAT-1α-Containing Complexes Play a Predominant Role in Induction of IFN-γ-Inducible Protein, 10 kDa (IP-10) by IFN-γ Alone or in Synergy with TNF-α
Authors: Majumder Sarmila , Zhou Lucy Z.-H. , Chaturvedi Priya , Babcock Gerald , Aras Sumer , Ransohoff Richard M. 
Published: December 2022

Abstract
Human IFN-γ-inducible protein, 10 kDa (hIP-10) and murine IP-10 (mIP-10) genes are induced by IFN-γ alone, and synergistically induced by TNF-α and IFN-γ. Upstream regions of the human and murine genes contain conserved regulatory motifs, including an IFN-stimulated response element (ISRE), which governs response of the mIP-10 gene to IFN-γ. Trans-acting factors mediating the IFN-γ response via ISRE remain incompletely defined. We examined ISRE-binding factors in the regulation of the hIP-10 gene. The requirement of p48 for hIP-10 induction by IFN-γ, with or without TNF-α, was demonstrated using p48-deficient U2A cells. An hIP-10 promoter-reporter mutant (mISRE3) that was relatively deficient for binding a related factor, IFN regulatory factor-1 (IRF-1) but competent for binding p48, was induced as well as the wild-type hIP-10 promoter, supporting the interpretation that p48 played a necessary and sufficient role in hIP-10 transcription. Genomic in vivo footprinting revealed IFN-γ/TNF-α-inducible binding at the ISRE consistent with the presence of p48 and associated factors, but not with IRF-1. Induction of hIP-10 by TNF-α/IFN-γ also required NFκB binding sites, which were protected in vivo and bound p65 homodimeric NFκB in vitro. These results documented the essential role of p48 (complexed with STAT-1α) for induction and sustained transcription of the IP-10 gene, strongly suggesting that IRF-1 is not required for IP-10 induction by these inflammatory cytokines.
Structural Aspects of the Interaction Between Heterogeneic Human Papillomavirus Type 1 E4-Specific T Cell Receptors and the Same Peptide/HLA-DQ8 Complex
Authors: Steele Jane C. , Young Stephen P. , Goodall Jane C. , Gallimore Phillip H. 
Published: December 2022

AbstractTCR usage has been studied in a panel of Th cell clones specific for the same peptide epitope (P N S Q D R G R P R R S D), derived from the human papillomavirus type 1 (HPV1) E4 protein, and restricted through HLA-DQ8. After identifying the V, D, and J genes used by the TCRs and sequencing across the V(D)J junctions, five different α-chain sequences and five different β-chain sequences, comprising six independent clones, were identified. A structural model of our E4 peptide/HLA-DQ8 complex predicted that the guanidinyl side chain on the arginine residue at position 6 of the peptide could exist in different orientations. An intramolecular interaction between this arginine and the glutamine residue at position four appeared to control this orientation. Interacting HPV1 E4-specific TCRs would therefore have to recognize the complex in different conformations, and molecular modeling of the TCRs suggested that this could be achieved by changing the dimensions of the central pocket formed where the CDR3 loops of the TCR α- and β-chains converge. It is known that interactions between bound peptide and amino acid residues lining the peptide-binding cleft of HLA molecules are important for determining the conformation and orientation of the peptide/MHC complex. The suggestion here that intramolecular interactions between amino acids of close proximity on the bound peptide are also important adds a further level of complexity to the mechanism by which TCRs interact with Ag.
Invariant Chain Can Bind MHC Class II at a Site Other Than the Peptide Binding Groove
Authors: Wilson Nancy A. , Wolf Paula , Ploegh Hidde , Ignatowicz Leszek , Kappler John , Marrack Philippa 
Published: December 2022

AbstractInvariant chain binds to class II molecules and guides them to the cell surface via the endosomes. Class II-associated invariant chain peptide (CLIP), a conserved sequence in an unstructured region of invariant chain, binds in the peptide binding groove of class II and is thought to be the major contributor to the interaction between invariant chain and class II molecules. However, other interaction sites between the two proteins may exist. The published data on this subject are conflicting. We have studied the ability of invariant chain to interact with a class II molecule in which the peptide binding groove of the protein is already occupied by a covalently attached peptide. Precipitation of these class II/peptide complexes with an Ab specific for this particular combination also precipitates invariant chain. This binding between class II/peptide and invariant chain is weak, and coprecipitation is only apparent in mild detergents. Thus, when the class II peptide binding groove is occluded by peptide and is not free to interact with CLIP, invariant chain can still bind the class II molecule at other lower affinity sites.
Active Sites in Complement Component C3 Mapped by Mutations at Indels
Authors: Ogata Ronald T. , Ai Rong , Low Pamela J. 
Published: December 2022

AbstractEngineered mutants of human complement component C3 were used to test the idea that sites of length polymorphisms in protein families (indels) can guide a search for protein:protein interaction sites. Sequence changes were introduced at each of the 27 indels in the C3/4/5 protein family, and mutants at 26 indels were expressed by transiently transfected COS cells. Expressed proteins were assayed 1) for concentration, by ELISA and by autoradiography of radiolabeled protein; 2) for classical pathway hemolytic activity; 3) for susceptibility to proteolytic activation by the alternative pathway and cobra venom factor C3 convertases; and 4) for susceptibility to complement factor I in the presence of factor H. Most of the mutations did not appreciably alter expression or activity relative to wild-type C3, consistent with the idea that most indels occur at the protein surface. Mutations at four indels severely damaged C3 functional activity, but did not affect the stability or structure of the protein, as assessed by their effects on expression by COS cells and on susceptibility to cleavage by C3 convertases and factor I. These indels are therefore near functionally important amino acid residues; they represent good candidates for sites of protein:protein interactions. Mutation of the sequence at a fifth indel altered the equilibrium between the latent and reacted C3 conformations, and mutations at 4 other indels substantially decreased both protein activity and expression. The mutants provided an overview of the structural and functional roles played by different parts of C3.
Mef2 Proteins, Required for Muscle Differentiation, Bind an Essential Site in the Ig λ Enhancer
Authors: Satyaraj Ebenezer , Storb Ursula 
Published: December 2022

Abstract
The Ig λ light chain gene enhancer has two unique essential motifs, λA and λB. The transcription factors that bind the λB motif have been identified as Pu.1 and Pu.1-interacting partner (Pip). We report here that the λA site includes a binding site for the myocyte-specific enhancer factor 2 (Mef2) family of transcription factors. Mef2 proteins were first described in muscle cells and, in vertebrates, include four known members designated A to D. Using a λA electrophoretic-mobility shift assay (EMSA), in conjunction with a high affinity Mef2 binding site and anti-Mef2 Abs, we show that members of the Mef2 family are present in nuclear extracts of λ-producing B cells and bind the λA site. Functional assays using the chloramphenicol acetyltransferase (CAT) reporter construct containing three copies of the λA motif demonstrate that the λA sequence can function as an enhancer in conjunction with the thymidine kinase (TK) promoter and is regulated by Mef2 proteins. Extrapolating from other systems where transcriptional regulation by Mef2 has been studied, other transcription factors may be involved along with Mef2 in transcriptional regulation at the λA site.
Proapoptotic Activity of aTrypanosoma cruziCeramide-Containing Glycolipid Turned on in Host Macrophages by IFN-γ
Authors: Freire-de-Lima Célio G. , Nunes Marise P. , Corte-Real Suzana , Soares Milena P. , Previato José O. , Mendonça-Previato Lúcia , DosReis George A. 
Published: December 2022

AbstractThe effects of glycoinositolphospholipid (GIPL), from the pathogenic protozoan Trypanosoma cruzi, and its isolated glycan and lipid (dihydroceramide) components, were investigated in J774 cells and primary macrophages. Isolated GIPL ceramide, but not intact GIPL or its glycan, induced intense fluid phase endocytosis when added exogenously. In the presence of the cytokine IFN-γ, GIPL ceramide induced marked apoptosis in J774 cells and macrophages, independent of nitric oxide secretion. When cells were preincubated with the GIPL-derived glycan chain, addition of intact GIPL induced macrophage apoptosis in the presence of IFN-γ. Synthetic C2-dihydroceramide also induced apoptosis in the presence of IFN-γ. Induction of apoptosis in T. cruzi-infected macrophages by GIPL ceramide plus IFN-γ led to increased parasite release compared with IFN-γ treatment alone. Viable parasites released comprised both infective trypomastigote and spheromastigote forms. These results identify a novel pathway by which T. cruzi glycosylphosphatidylinositol family molecules affect host macrophages, with implications for the infectious process.
Novel C-Terminally Truncated Isoforms of the CXC Chemokine β-Thromboglobulin and Their Impact on Neutrophil Functions
Authors: Ehlert Jan Erik , Gerdes Johannes , Flad Hans-Dieter , Brandt Ernst 
Published: December 2022

AbstractThe neutrophil agonist neutrophil-activating peptide-2 (NAP-2) arises through proteolytic processing of platelet-derived N-terminally extended inactive precursors, the most abundant one being connective tissue-activating peptide-III (CTAP-III). Apart from N-terminal processing, C-terminal processing also appears to participate in the functional regulation of NAP-2, as indicated by our recent identification of an isoform missing four C-terminal amino acids, NAP-2 (1–66), which was about threefold more potent than full-size NAP-2. In the present study, we report on the discovery and identification of natural NAP-2 (1–63), an isoform truncated by seven C-terminal residues. Functional and receptor-binding analyses demonstrated that NAP-2 (1–63) represents the most active isoform, being about fivefold more potent than full-size NAP-2. Analyses of rNAP-2 isoforms successively truncated at the C terminus by up to eight residues suggest functionally important roles for acidic residues and for the leucine at position 63, a residue highly conserved within CXC chemokines. Finally, we report on a novel C-terminally truncated isoform of CTAP-III (CTAP-III (1–81)) representing the potential precursor of NAP-2 (1–66). We show that C-terminal truncation in CTAP-III enhances its potency to desensitize chemokine-induced neutrophil activation, indicating that C-terminal processing might not only serve to enhance neutrophil activation, but might as well participate in the down-regulation of an inflammatory response.
Fusion of Azurophil Granules with Phagosomes and Activation of the Tyrosine Kinase Hck Are Specifically Inhibited During Phagocytosis of Mycobacteria by Human Neutrophils
Authors: N’Diaye Elsa-Noah , Darzacq Xavier , Astarie-Dequeker Catherine , Daffé Mamadou , Calafat Jero , Maridonneau-Parini Isabelle 
Published: December 2022

AbstractPathogenic mycobacteria parasitize macrophages and reside within phagosomes, which do not fuse with lysosomal granules. Mycobacteria are also internalized by neutrophils, which possess at least two types of granules, specific and azurophil granules, the latter being specialized lysosomes. Here, we investigated the ability of mycobacteria to inhibit the fusion of these granules with their phagosomes in human neutrophils. It was found that when pathogenic (Mycobacterium kansasii and Mycobacterium avium) or nonpathogenic (Mycobacterium smegmatis and Mycobacterium phlei) mycobacteria were internalized by neutrophils, they induced the inhibition of azurophil granule fusion with phagosomes even when they were serum opsonized. In contrast, secretion of specific granule content and production of O2−, both of which contribute to the neutrophil bactericidal response, were triggered. Hck is a Src family tyrosine kinase associated with azurophil granules. During internalization of zymosan, azurophil granules fused with phagosomes and Hck was activated and translocated to the phagosomal membrane, whereas in neutrophils engulfing mycobacteria, Hck did not translocate and remained unactivated. The activation of the tyrosine kinase Fgr was not affected. These results indicate that 1) pathogenic and nonpathogenic mycobacteria trigger similar bactericidal responses in neutrophils, 2) phagocytosis and fusion of azurophil granules can be uncoupled by mycobacteria, and 3) Hck could be one of the key elements of the azurophil secretory pathway that are altered during phagocytosis of mycobacteria.
Role of IL-6 and the Soluble IL-6 Receptor in Inhibition of VCAM-1 Gene Expression
Authors: Oh Jae-Wook , Van Wagoner Nicholas J. , Rose-John Stefan , Benveniste Etty N. 
Published: December 2022

AbstractAdhesion molecules such as VCAM-1 and ICAM-1 are increased in the central nervous system (CNS) during inflammatory responses and contribute to extravasation of leukocytes across the blood-brain barrier (BBB) and into CNS parenchyma. Astrocytes contribute to the structural integrity of the BBB and can be induced to express VCAM-1 and ICAM-1 in response to cytokines such as TNF-α, IL-1β, and IFN-γ. In this study, we investigated the influence of IL-6 on astroglial adhesion molecule expression. IL-6, the soluble form of the IL-6R (sIL-6R), or both IL-6 plus sIL-6R, had no effect on VCAM-1 or ICAM-1 gene expression. Interestingly, the IL-6/sIL-6R complex inhibited TNF-α-induced VCAM-1 gene expression but did not affect TNF-α-induced ICAM-1 expression. The inhibitory effect of IL-6/sIL-6R complex was reversed by the inclusion of anti-IL-6R and gp130 Abs, demonstrating the specificity of the response. A highly active fusion protein of sIL-6R and IL-6, covalently linked by a flexible peptide, which is designated H-IL-6, also inhibited TNF-α-induced VCAM-1 expression. sIL-6R alone was an effective inhibitor of TNF-α-induced VCAM-1 due to endogenous IL-6 production. These results indicate that the IL-6 system has an unexpected negative effect on adhesion molecule expression in glial cells and may function as an immunosuppressive cytokine within the CNS.
Oncostatin M Up-Regulates Tissue Inhibitor of Metalloproteinases-3 Gene Expression in Articular Chondrocytes via De Novo Transcription, Protein Synthesis, and Tyrosine Kinase- and Mitogen-Activated Protein Kinase-Dependent Mechanisms
Authors: Liand Wen Qing , Zafarullah Muhammad 
Published: December 2022

AbstractCytokines and growth factors regulate physiologic and pathologic turn-over of cartilage extracellular matrix (ECM) by altering the balance between tissue inhibitors of metalloproteinases (TIMPs) and matrix metalloproteinases (MMPs). Oncostatin M (OSM) is a cytokine of the IL-6 family whose levels are increased in the serum and synovial fluids of patients with rheumatoid arthritis. We examined responsiveness of the TIMP-3 gene to OSM in articular chondrocytes and studied the regulatory and signaling mechanisms of this response. OSM induced TIMP-3 mRNA and protein expression in a dose- and time-dependent fashion. Concomitantly, stromelysin-1 and collagenase-1 RNA and activities were also induced. A cartilage matrix growth factor, TGF-β, induced TIMP-3, but combined OSM and TGF-β did not further increase the extent of induction, suggesting a lack of synergy between the two. OSM induction of TIMP-3 gene expression was dependent upon de novo protein synthesis and transcription. RNA decay time-courses suggested that the OSM-mediated increase of TIMP-3 RNA was not due to enhanced message stability and, along with inhibition by actinomycin-D, suggested a transcriptional control. The antiinflammatory glucocorticoid, dexamethasone, down-regulated this augmentation. Investigation of the signaling mechanisms revealed that protein tyrosine kinase inhibitors genistein and herbimycin A, as well as the specific mitogen-activated protein kinase (MAPK) kinase inhibitor PD98059, suppressed OSM-induced TIMP-3 message expression, suggesting the involvement of tyrosine kinases and mitogen-activated protein kinase cascades in the signaling of OSM leading to TIMP-3 RNA enhancement. Thus OSM can potentially alter the cartilage matrix metabolism by regulating genes like TIMP-3 and matrix metalloproteinases.
Transgenic Expression of IFN-α in the Central Nervous System of Mice Protects Against Lethal Neurotropic Viral Infection but Induces Inflammation and Neurodegeneration
Authors: Akwa Yvette , Hassett Daniel E. , Eloranta Maija-Leena , Sandberg Kristian , Masliah Eliezer , Powell Henry , Whitton J. Lindsay , Bloom Floyd E. , Campbell Iain L. 
Published: December 2022

Abstract
Type I IFNs, which include IFN-α, appear to have complex and broad-ranging actions in the central nervous system (CNS) that may result in protection or injury. To better understand these issues, we generated transgenic mice that produce IFN-α1 chronically from astrocytes. These glial fibrillary acidic protein-IFN-α transgenic mice developed a progressive inflammatory encephalopathy, with marked calcium mineralization, meninoencephalitis, gliosis, and neurodegeneration. Many features of this murine encephalopathy resembled those found in certain human encephalopathies of unknown etiology; these diseases, exemplified by Aicardi-Goutières syndrome and some viral encephalopathies, show increased intrathecal production of IFN-α. Our data suggest that IFN-α overproduction may be the primary factor initiating these human diseases. Following intracerebral infection with lymphocytic choriomeningitis virus, glial fibrillary acidic protein-IFN-α mice had significantly increased survival rates associated with markedly reduced virus titers and immune pathology in the brain but normal peripheral CTL responses. Therefore, the production of IFN-α in the CNS can be a two-edged sword that on the one hand confers protection against a lethal viral infection but on the other causes significant injury to the brain. These transgenic mice provide a novel animal model in which to further evaluate the mechanisms that underlie the diverse actions of type I IFNs in the intact CNS.
Antibodies Against IL-12 Prevent Superantigen-Induced and Spontaneous Relapses of Experimental Autoimmune Encephalomyelitis
Authors: Constantinescu Cris S. , Wysocka Maria , Hilliard Brendan , Ventura Elvira S. , Lavi Ehud , Trinchieri Giorgio , Rostami Abdolmohamad 
Published: December 2022

AbstractImmunization of (PL/J × SJL/J)F1 mice with myelin basic protein (MBP) induces relapsing experimental autoimmune encephalomyelitis (EAE). Relapses occur 7 to 10 days after recovery from the initial paralysis. Staphylococcal enterotoxins (SE) A or B, administered after recovery from the initial paralysis, induce immediate relapses. IL-12 is involved in the induction of EAE. Here, we show that SEA and SEB induce IL-12 in splenocytes from (PL/J × SJL/J)F1 mice in vitro and increase the level of IL-12 in the sera of mice treated with these superantigens. IL-12 administration mimics SE in inducing spontaneous relapses and in enhancing the severity and frequency of spontaneous relapses. IL-12 neutralization blocks SE-induced and subsequent relapses of EAE, and, when instituted after recovery from the initial attack, prevents spontaneous relapse. This is the first report of prevention of relapses of EAE with anti-IL-12 Ab, an approach which may prove useful in the prevention of exacerbations in multiple sclerosis.