bluuebunny/crossref_metadata_2025_split huggingface dataset:
Sea Urchin Coelomocytes Specifically Express a Homologue of the Complement Component C3
Authors: Al-Sharif Walid Z. , Sunyer J. Oriol , Lambris John D. , Smith L. Courtney 
Published: December 2022

AbstractA homologue of complement component C3 (SpC3) has been cloned and sequenced from the purple sea urchin, Strongylocentrotus purpuratus. The preprocessed, deduced protein size is estimated to be 186 kDa with a short leader and two chains, α and β. There are cysteines in conserved positions for interchain disulfide bonding, and there is a conserved thioester site in the α-chain with an associated histidine. There are five consensus N-linked glycosylation sites, and putative cleavage sites for factor I and C3 convertase. Partially purified SpC3 on protein gels shows a nonreduced size of 210 kDa and, under reducing conditions, reveals an α-chain of 130 kDa and a β-chain of 80 kDa. These sizes are larger than the deduced sizes, suggesting that the protein has carbohydrates added to most of the consensus N-linked glycosylation sites. Phylogenetic analysis of SpC3 compared with other members of the thioester protein family, which includes C3, C4, C5, and α2-macroglobulin, shows that SpC3 is the first divergent complement protein, falling at the base of the complement protein clade. Transcripts from the SpC3 gene (Sp064) are 9 kb, and the gene is expressed specifically in coelomocytes, which are the immunocytes in the sea urchin. Genome blots suggest that SpC3 is encoded by a single copy gene per haploid genome. This is the first identification of a complement component in an invertebrate, and suggests homology of the innate immune system within the deuterostome lineage of animals.
Regulation of Hyaluronan-Induced Chemokine Gene Expression by IL-10 and IFN-γ in Mouse Macrophages
Authors: Horton Maureen R. , Burdick Marie D. , Strieter Robert M. , Bao Clare , Noble Paul W. 
Published: December 2022

Abstract
Turnover of the extracellular matrix (ECM), activation of macrophages, and accumulation of chemokines/cytokines are all hallmarks of chronic inflammation. Extracellular matrix components, such as hyaluronan (HA), have recently been shown to influence macrophage effector functions, such as the release of inflammatory chemokines and cytokines. Although low m.w. fragments of the glycosaminoglycan HA induce macrophages to secrete numerous inflammatory mediators, the mechanisms regulating ECM-induced macrophage activation are poorly understood. We have examined the effects of IL-10 and IFN-γ on HA-induced chemokine gene expression in primary mouse macrophages. We found that IL-10 and IFN-γ independently inhibit HA-induced expression of macrophage inflammatory protein-1α (MIP-1α), MIP-1β, and KC at both the mRNA and protein levels. Whereas IL-10 inhibited most of the HA-induced chemokines tested, IFN-γ selectively inhibited only MIP-1α, MIP-1β, and KC. This inhibition did not require prestimulation and occurred even when the cytokines were added up to 3 h after stimulation with HA. For MIP-1α, the inhibition by IFN-γ occurred at the level of transcription, whereas IL-10 predominantly decreased the stability of MIP-1α mRNA. IFN-γ and IL-10 equally inhibited macrophage expression of MIP-1β mRNA at the level of transcription, but MIP-1β mRNA stability was decreased to a greater extent by IL-10. These data identify a previously unrecognized role for IL-10 and IFN-γ as regulators of ECM-induced macrophage expression of inflammatory chemokines.
Treatment with an Anti-IL-4 Monoclonal Antibody Blocks Suppression of Collagen-Induced Arthritis in Mice by Oral Administration of Type II Collagen
Authors: Yoshino Shin 
Published: December 2022

AbstractOral administration of type II collagen (CII) has been shown to suppress collagen-induced arthritis (CIA) in experimental animals. However, the exact mechanism by which CIA is suppressed following administration of CII remains to be investigated, although it was demonstrated that active suppression by regulatory T cells might be involved in the suppression. Therefore, we have examined whether the inhibitory cytokine IL-4 plays a role in the suppression of CIA, by using an anti-IL-4 mAb (11B11 mAb). Mice were fed daily with CII over a period of 10 days before immunization with CII. 11B11 mAb was i.p. injected 30 min before each oral administration of CII. The results showed that treatment with 11B11 mAb markedly blocked suppression of CIA by the oral Ag. The blockade of suppression of CIA by the anti-IL-4 mAb was associated with the blockade of augmentation of IL-4 secretion in CII-fed mice. The treatment with 11B11 mAb also resulted in the prevention of decreases in anti-CII IgG2a Ab production, DTH responses to CII, proliferation of lymphoid cells to CII, and IFN-γ secretion in mice given CII orally. Thus, the neutralization of IL-4 by an anti-IL-4 Ab appears to be effective in blocking suppression of CIA by oral administration of CII, suggesting that IL-4 may be critically involved in its suppression.
Distinct Peptide Loading Pathways for MHC Class II Molecules Associated with Alternative Ii Chain Isoforms
Authors: Bikoff Elizabeth K. , Kenty George , Van Kaer Luc 
Published: December 2022

AbstractMutant mouse strains expressing either p31 or p41 Ii chain appear equally competent with respect to their class II functional activities including Ag presentation and CD4+ T cell development. To further explore possibly divergent roles provided by alternative Ii chain isoforms, we compare class II structure and function in double mutants also carrying a null allele at the H2-DM locus. As for DM mutants expressing wild-type Ii chain, AαbAβb dimers present in DM-deficient mice expressing either Ii chain isoform appear equally occupied by class II-associated Ii chain-derived peptides (CLIP). Surprisingly, in functional assays, these novel mouse strains exhibit strikingly different phenotypes. Thus, DM-deficient mice expressing wild-type Ii chain or p31 alone are both severely compromised in their abilities to present peptides. In contrast, double mutants expressing the p41 isoform display markedly enhanced peptide-loading capabilities, approaching those observed for wild-type mice. The present data strengthen evidence for divergent class II presentation pathways and demonstrate for the first time that functionally distinct roles are mediated by alternatively spliced forms of the MHC class II-associated Ii chain in a physiologic setting.
CD8+ Memory T Cells (CD44high, Ly-6C+) Are More Sensitive than Naive Cells (CD44low, Ly-6C−) to TCR/CD8 Signaling in Response to Antigen
Authors: Curtsinger Julie M. , Lins Debra C. , Mescher Matthew F. 
Published: December 2022

AbstractMemory CD8+ T cells from mice previously primed with alloantigen (alloAg) can respond in vitro to IL-2 and purified class I alloAg presented on microspheres, while no response can be detected using cells from naive mice. Similar results have been obtained using cells from OT-1 mice expressing a transgenic TCR that is specific for OVA257–264 (SIINFEKL) peptide bound to H-2Kb. A population of resting memory cells (defined on the basis of low forward scatter and CD44high, Ly-6C+, CD25−, CD69− surface phenotype) that is present in the OT-1 mice exhibits a substantially higher sensitivity to Ag-stimulation than do naive cells (CD44low, Ly-6C−) expressing the same TCR. CD44high cells respond vigorously to H-2Kb immobilized on microspheres and pulsed with peptide, while CD44low cells respond weakly and only at high class I density and peptide concentration. The Ag-presenting surface only has ligands for TCR and CD8 (class I and peptide), thus ruling out the possibility that differences are due to ligand binding by other adhesion or costimulatory receptors that are expressed at high levels on the memory cells. Experiments using anti-TCR mAb as the stimulus and coimmobilized non-Ag class I as a ligand for CD8 suggest that the difference between naive and memory cells may be at the level of stimulation through the TCR. Thus, in addition to expressing increased levels of adhesion receptors that may enhance responses to Ag on APCs, memory CD8+ T cells appear to be intrinsically more sensitive than naive cells to stimulation through the TCR/CD8 complex.
Ontogeny of the Heavy Chain Immunoglobulin Repertoire in Fetal Liver and Bone Marrow
Authors: Delassus Sylvie , Darche Sylvie , Kourilsky Philippe , Cumano Ana 
Published: December 2022

AbstractWe studied the kinetics of maturation of B cell progenitors in the mouse embryo, from day 15 of development to birth, both in liver and bone marrow. The analysis of Ig heavy chain rearrangements at different time points of late fetal development shows that oligoclonal patterns of VH-D-JH rearrangements are detected by day 15 in fetal liver. The pattern is polyclonal and diverse by day 17; however, 80% of the rearrangements are nonproductive. In bone marrow, the pattern of rearrangements is less diverse at birth, although the percentage of nonproductive rearrangements approaches adult bone marrow levels (35–40%). After day 17 in fetal liver, there is a sudden reversal in the percentage of nonproductive rearrangements that reaches 33% at day 19 (birth). Maturation of B cells, as measured by the fraction of surface Ig+ in total B220+ cells and the presence of N sequence additions in VH-D-JH joints, occurs in the marrow before fetal liver. These results demonstrate that the lymphopoietic environment in fetal liver and bone marrow of animals at the same stage of development is functionally distinct.
Stimulation of Human T Lymphocytes by LPS Is MHC Unrestricted, But Strongly Dependent on B7 Interactions
Authors: Mattern Taila , Flad Hans-Dieter , Brade Lore , Rietschel Ernst T. , Ulmer Artur J. 
Published: December 2022

AbstractRecently, we have shown that LPS is a potent inducer of human T cell proliferation and lymphokine production. However, the activation of T cells by LPS has been demonstrated to be monocyte dependent and to require direct cell-to-cell contact. Here, we investigated the role of monocytes as accessory cells and the requirement for costimulatory signals in more detail. We found that the accessory cell activity of monocytes during LPS-induced T cell proliferation is characterized by the following features: LPS-primed monocytes are competent stimulators of T cell proliferation; interaction of LPS with monocytes during the priming step is dependent on CD14 and is sensitive to ammonia; monocyte/T cell interactions are not MHC restricted but are strongly dependent on interactions of CD28 and/or CTLA-4 on T cells and their ligands CD80 and/or CD86 on monocytes. CD80 seems to be crucial for the activation of T cells by monocytes, since monocytes expressing CD86 but not CD80 after LPS stimulation were unable to stimulate T cells; IL-12, at least as a costimulatory factor, but not IL-15, is important in LPS-induced T cell proliferation. Taken together, our results indicate that LPS acts neither as a mitogen, nor as a superantigen, nor as an Ag. The activation of human T cells by LPS requires the help of accessory functions by primed monocytes and is MHC unrestricted but needs costimulatory signals via CD28 and/or CTLA-4.
Crucial Role of TNF Receptor Type 1 (p55), But Not of TNF Receptor Type 2 (p75), in Murine Toxoplasmosis
Authors: Deckert-Schlüter Martina , Bluethmann Horst , Rang Andrea , Hof Herbert , Schlüter Dirk 
Published: December 2022

AbstractTNF-α exerts its biologic activity through two distinct receptors, TNF receptor type 1 (TNFR1, p55) and TNF receptor type 2 (TNFR2, p75). To analyze their function in toxoplasmosis, we orally infected mice genetically deficient for TNFR1 (TNFR10/0), TNFR2 (TNFR20/0), or both TNF receptors (TNFR1/20/0), as well as wild-type (wt) mice with a low-virulent strain of Toxoplasma gondii. TNFR1/20/0 and TNFR10/0 mice succumbed to toxoplasmosis within 17 and 27 days, respectively, whereas TNFR20/0 and wt mice were equally resistant to acute toxoplasmosis. Histopathology attributed death of TNFR1/20/0 and TNFR10/0 mice to a fulminant necrotizing encephalitis. In addition, pneumonia contributed to the fatal outcome. The poor prognosis of TNFR1/20/0 and TNFR10/0 mice was reflected by a significantly increased parasitic load in the brain and lung as compared with TNFR20/0 and wt mice. Immunohistochemistry demonstrated a remarkable reduction of inducible nitric oxide synthase protein in brain and lung of TNFR1/20/0 and TNFR10/0 as compared with TNFR20/0 and wt mice. Reverse-transcribed PCR showed that in contrast to TNFR20/0 and wt mice, TNFR10/0 mice were unable to up-regulate inducible nitric oxide synthase mRNA transcripts in the course of infection, whereas intracerebral levels of IFN-γ, TNF-α, and IL-1β mRNA transcripts, recruitment of immune cells to the brain, and the amount of apoptotic cells in inflammatory foci did not differ significantly among the various experimental groups. These results illustrate that in Toxoplasma encephalitis, TNF-α-mediated immune responses are of crucial importance and that signaling through TNFR1, but not TNFR2, provides the stimulus required for the induction of protective nitric oxide.
A Critical Role for IL-13 in Resistance to Intestinal Nematode Infection
Authors: Bancroft Allison J. , McKenzie Andrew N. J. , Grencis Richard K. 
Published: December 2022

AbstractMice in which either the IL-4 or the IL-13 gene has been disrupted (IL-4 KO and IL-13 KO) were susceptible to infection with the intestinal nematode Trichuris muris, whereas their wild-type littermates were highly resistant and expelled the parasite. IL-4 KO mice showed diminished Th2-type responses with T. muris infection and also failed to produce parasite-specific IgG1 Abs. Although IL-13 KO mice made reduced Th2-type responses early in infection, they were capable of generating strong Th2-type responses at later time points and were unable to regulate the magnitude of their Ab isotype response. These results confirm the importance of IL-4 in resistance to T. muris and provide the first demonstration of an important role for IL-13 in resistance to helminth infection. The IL-13 KO mouse had a separate phenotype to that of the IL-4 KO mouse, suggesting that both IL-4 and IL-13 play important yet different roles in mediating immunity to intestinal helminths.
Activation of Caspase 3 (CPP32)-Like Proteases Is Essential for TNF-α-Induced Hepatic Parenchymal Cell Apoptosis and Neutrophil-Mediated Necrosis in a Murine Endotoxin Shock Model
Authors: Jaeschke Hartmut , Fisher Michael A. , Lawson Judy A. , Simmons Carol A. , Farhood Anwar , Jones David A. 
Published: December 2022

AbstractEndotoxin (ET)-induced liver failure is characterized by parenchymal cell apoptosis and inflammation leading to liver cell necrosis. Members of the caspase family have been implicated in the signal transduction pathway of apoptosis. The aim of this study was to characterize ET-induced hepatic caspase activation and apoptosis and to investigate their effect on neutrophil-mediated liver injury. Treatment of C3Heb/FeJ mice with 700 mg/kg galactosamine (Gal) and 100 μg/kg Salmonella abortus equi ET increased caspase 3-like protease activity (Asp-Val-Glu-Asp-substrate) by 1730 ± 140% at 6 h. There was a parallel enhancement of apoptosis (assessed by DNA fragmentation ELISA and terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling assay). In contrast, activity of caspase 1 (IL-1β-converting enzyme)-like proteases (Tyr-Val-Ala-Asp-substrate) did not change throughout the experiment. Caspase 3-like protease activity and apoptosis was not induced by Gal/ET in ET-resistant mice (C3H/HeJ). Furthermore, only murine TNF-α but not IL-1αβ increased caspase activity and apoptosis. Gal/ET caused neutrophil-dependent hepatocellular necrosis at 7 h (area of necrosis, 45 ± 3%). Delayed treatment with the caspase 3-like protease inhibitor Z-Val-Ala-Asp-CH2F (Z-VAD) (10 mg/kg at 3 h) attenuated apoptosis by 81 to 88% and prevented liver cell necrosis (≤5%). Z-VAD had no effect on the initial inflammatory response, including the sequestration of neutrophils in sinusoids. However, Z-VAD prevented neutrophil transmigration and necrosis. Our data indicate that activation of the caspase 3 subfamily of cysteine proteases is critical for the development of parenchymal cell apoptosis. In addition, excessive hepatocellular apoptosis can be an important signal for transmigration of primed neutrophils sequestered in sinusoids.
Regulation of Macrophage Phagocytosis of Apoptotic Cells by cAMP
Authors: Rossi Adriano G. , McCutcheon Judith C. , Roy Noémi , Chilvers Edwin R. , Haslett Christopher , Dransfield Ian 
Published: December 2022

AbstractRegulation of macrophage capacity to remove apoptotic cells may control the balance of apoptotic and necrotic leukocytes at inflamed foci and the extent of leukocyte-mediated tissue damage. Although the molecules involved in the phagocytic process are beginning to be defined, little is known about the underlying regulatory and signaling mechanisms controlling this process. In this paper, we have investigated the effects of treatment of human monocyte-derived macrophages with PGs and other agents that elevate intracellular cAMP on phagocytosis. PGE2 and PGD2 specifically reduced the proportion of macrophages that phagocytosed apoptotic cells. Similar results were obtained with the membrane-permeable cAMP analogues dibutyryl-cAMP and 8-bromo-cAMP but not with the cGMP analogue dibutyryl-GMP. Consistent with the observation that phagocytosis was inhibited by cAMP elevation, treatment of monocyte-derived macrophages with PGE2 resulted in rapid, transient increase in levels of intracellular cAMP. These effects were not due to nonspecific inhibition of monocyte-derived macrophage phagocytosis given that ingestion of Ig-opsonized erythrocytes was unaffected. Elevation of cAMP induced morphologic alterations indicative of changes in the adhesive status of the macrophage, including cell rounding and disassembly of structures that represent points of contact with substrate containing actin and talin. These results strongly suggest that rapid activation of cAMP signaling pathways by inflammatory mediators regulates processes that limit tissue injury and that modulation of cAMP levels represents an additional therapeutic target in the control of resolution of inflammation.
Cutting Edge: Role of the Inositol Phosphatase SHIP in B Cell Receptor-Induced Ca2+ Oscillatory Response
Authors: Okada Hidetaka , Bolland Silvia , Hashimoto Akiko , Kurosaki Mari , Kabuyama Yukihito , Iino Masamitsu , Ravetch Jeffrey V. , Kurosaki Tomohiro 
Published: December 2022

AbstractSrc homology-2 domain-containing inositol polyphosphate 5′-phosphatase (SHIP) is a recently identified protein that has been implicated as an important signaling molecule. Although SHIP has been shown to participate in the FcγRIIB-mediated inhibitory signal, the functional role of SHIP in activation responses by immunoreceptor tyrosine-based activation motif-bearing receptors such as B cell receptor (BCR) remains unclear. Indeed, it has been proposed that SHIP serves as a linking molecule for the regulation of the extracellular signal-regulated kinase pathway in BCR signaling, because SHIP associates with Shc. We now report that SHIP-deficient DT40 B cells display enhanced Ca2+ mobilization in response to BCR ligation, whereas extracellular signal-regulated kinase activation is unaffected. This Ca2+ enhancement is due to a sustained intracellular Ca2+ increase or to long-lasting Ca2+ oscillations by loss of SHIP, as revealed by single-cell Ca2+ imaging analysis. These results demonstrate the importance of SHIP in B cell activation by the modulation of Ca2+ mobilization.
Cutting Edge: LFA-1 Interaction with ICAM-1 and ICAM-2 Regulates Th2 Cytokine Production
Authors: Salomon Benoı̂t , Bluestone Jeffrey A. 
Published: December 2022

AbstractThe role of CD28/B7 and LFA-1/ICAM costimulation in proliferation and Th1/Th2 differentiation of naive CD4+ T cells was addressed using T cells from DO11.10 TCR transgenic mice stimulated by dendritic cells. The blockade of either CD28/B7 or LFA-1/ICAM interactions partially inhibited T cell proliferation. By comparison, blocking CD28/B7 costimulation inhibited IL-4 and IL-5 (Th2 cytokine) production, whereas blocking LFA-1/ICAM-1 or LFA-1/ICAM-2 led to a significant increase (15- to 40-fold) of Th2 cytokines. The combination of anti-ICAM-1 and anti-ICAM-2 mAbs had a synergistic effect with a 100- to 1000-fold increase of Th2 cytokine production. Thus, these two costimulatory pathways have opposing roles in the regulation of Th2 development.
Anti-CD4 Monoclonal Antibody-Induced Tolerance to MHC-Incompatible Cardiac Allografts Maintained by CD4+ Suppressor T Cells That Are Not Dependent upon IL-4
Authors: Hall Bruce M. , Fava Lisa , Chen Juchuan , Plain Karren M. , Boyd Rochelle A. , Spicer S. Timothy , Berger Manuela F. 
Published: December 2022

AbstractAnti-CD4 mAb-induced tolerance to transplanted tissues has been proposed as due to down-regulation of Th1 cells by preferential induction of Th2 cytokines, especially IL-4. This study examined the role of CD4+ cells and cytokines in tolerance to fully allogeneic PVG strain heterotopic cardiac allografts induced in naive DA rats by treatment with MRC Ox38, a nondepleting anti-CD4 mAb. All grafts survived &gt;100 days but had a minor mononuclear cell infiltrate that increased mRNA for the Th1 cytokines IL-2, IFN-γ, and TNF-β, but not for Th2 cytokines IL-4 and IL-6 or the cytolytic molecules perforin and granzyme A. These hosts accepted PVG skin grafts but rejected third-party grafts, which were not blocked by anti-IL-4 mAb. Cells from these tolerant hosts proliferated in MLC and produced IL-2, IFN-γ, and IL-4 at levels equivalent to naive cells. Unfractionated and CD4+ T cells, but not CD8+ T cells, transferred specific tolerance to irradiated heart grafted hosts and inhibited reconstitution of rejection by cotransferred naive cells. This transfer of tolerance was associated with normal induction of IL-2 and delayed induction of IFN-γ, but not with increased IL-4 or IL-10 mRNA. Transfer of tolerance was also not inhibited by anti-IL-4 mAb. This study demonstrated that tolerance induced by a nondepleting anti-CD4 mAb is maintained by a CD4+ suppressor T cell that is not associated with preferential induction of Th2 cytokines or the need for IL-4; nor is it associated with an inability to induce Th1 cytokines or anergy.
HSV-1 Glycoprotein I-Reactive TCRγδ Cells Directly Recognize the Peptide Backbone in a Conformationally Dependent Manner
Authors: Sciammas Roger , Bluestone Jeffrey A. 
Published: December 2022

Abstract
Despite the description of numerous antigenic ligands recognized by TCRγδ cells, detailed information concerning the structural nature of these antigenic epitopes is lacking. In addition, the recent descriptions of human TCRγδ cells recognizing mycobacterium-derived low m.w. lipid molecules confirms that the spectrum and nature of biologic structures that are capable of being recognized by TCRγδ cells are unclear. We have previously described a murine TCRγδ cell clone, TgI4.4, that is reactive to herpes simplex virus (HSV)-1 glycoprotein I (gI). Unlike TCRαβ-mediated, MHC-restricted Ag recognition but similar to Ig Ag recognition, TgI4.4 recognizes purified gI directly, in the absence of Ag processing or presentation. Since gI is a complex glycoprotein, the nature of the antigenic epitope was investigated. First, gI recognition by TgI4.4 is conformationally dependent, as revealed by denaturation and proteolytic experiments. Secondly, the epitope recognized by TgI4.4 was mapped to the amino terminus by using insertion mutants of gI. Lastly, TgI4.4 recognizes the gI protein directly since completely deglycosylated forms of gI are efficiently recognized. Therefore, TCRγδ cells are capable of recognizing a variety of molecular structures, including proteins. The ability of TgI4.4 to recognize a nonglycosylated form of gI suggests that HSV-1 recognition by TCRγδ cells in vivo is not limited by cell-specific glycosylation patterns or glycosylation-dependent conformational influences.