bluuebunny/crossref_metadata_2025_split huggingface dataset:
FTY720, a Novel Immunosuppressant, Induces Sequestration of Circulating Mature Lymphocytes by Acceleration of Lymphocyte Homing in Rats. I. FTY720 Selectively Decreases the Number of Circulating Mature Lymphocytes by Acceleration of Lymphocyte Homing
Authors: Chiba Kenji , Yanagawa Yoshiki , Masubuchi Yumi , Kataoka Hirotoshi , Kawaguchi Takafumi , Ohtsuki Makio , Hoshino Yukio 
Published: January 2023

AbstractFTY720, given i.v. or orally at 0.03 mg/kg or more, significantly prolonged skin allograft survival in a dose-dependent manner and showed more potent immunosuppressive activity than cyclosporin A (CsA) or tacrolimus (FK506) in MHC-incompatible rat strains of WKAH donors and F344 recipients. However, unlike CsA or FK506, FTY720 up to 1000 nM did not affect IL-2 production in allogeneic MLC. Within 3 to 24 h after a single oral administration of FTY720 at 0.1 to 1 mg/kg, the number of lymphocytes in the rats was markedly decreased in the peripheral blood and thoracic duct lymph and partially in spleen. By contrast, the number of lymphocytes in peripheral lymph nodes (PLN), mesenteric lymph nodes (MLN), and Peyer’s patches (PP) was significantly increased at the same time. Intravenous transfusion of calcein-labeled rat lymphocytes into rats revealed that FTY720 significantly accelerated lymphocyte homing to PLN, MLN, and PP, dose dependently. Since FTY720-induced lymphocyte homing was completely blocked by simultaneous treatment of the calcein-labeled lymphocytes with mAbs against CD62L, CD49d, and CD11a before the transfusion, the acceleration of lymphocyte homing by FTY720 appears to be mediated by lymphocyte-homing receptors. These findings indicate that FTY720 sequesters circulating mature lymphocytes into PLN, MLN, and PP by acceleration of lymphocyte homing and thereby decreases the number of lymphocytes in peripheral blood, thoracic duct lymph, and spleen. Based on these observations, sequestration of circulating mature-lymphocytes is presumed to be a main mechanism of the immunosuppressive activity of FTY720.
Regulation of TNF-α Production in Activated Mouse Macrophages by Progesterone
Authors: Miller Lance , Hunt Joan S. 
Published: January 2023

Abstract
The purpose of this study was to investigate the relationships between macrophage production of TNF-α and female hormones. Northern blot hybridization experiments showed that the female sex steroid hormone, progesterone, decreases steady state levels of TNF-α mRNA in LPS-activated mouse macrophages (RAW 264.7 and ANA-1 cells) in vitro. The production of intracellular and secreted TNF-α protein, as determined by ELISA, was decreased in both progesterone- and dexamethasone-treated, LPS-stimulated macrophages. Estrogen had no effect on expression of the TNF-α gene in mouse macrophages and did not alter progesterone-mediated suppression. Additional experiments conducted to investigate the mechanism of action of progesterone showed that this hormone, like dexamethasone, elevates steady state mRNA levels of IκBα and increases the levels of IκBα protein that are translocated from the cytoplasm to the nucleus. Thus, progesterone is a potent inhibitor of steady state levels TNF-α mRNA and TNF-α protein production in activated macrophages and may achieve this result through effects on an inhibitor of NF-κB.
Central Nervous System Microglial Cell Activation and Proliferation Follows Direct Interaction with Tissue-Infiltrating T Cell Blasts
Authors: Sedgwick Jonathon D. , Ford Andrew L. , Foulcher Eléna , Airriess Rhonda 
Published: January 2023

Abstract
Central nervous system (CNS)-resident macrophages (microglia) normally express negligible or low level MHC class II, but this is up-regulated in graft-vs-host disease (GvHD), in which a sparse CNS T cell infiltrate is observed. Relative to microglia from the normal CNS, those from the GvHD-affected CNS exhibited a 5-fold up-regulation of characteristically low CD45, MHC class II expression was increased 10- to 20-fold, and microglial cell recoveries were enhanced substantially. Immunohistologic analysis revealed CD4+αβTCR+CD2+ T cells scattered infrequently throughout the CNS parenchyme, 90% of which were blast cells of donor origin. An unusual clustering of activated microglia expressing strongly enhanced levels of CD11b/c and MHC class II was a feature of the GvHD-affected CNS, and despite the paucity of T lymphocytes present, activated microglial cell clusters were invariably intimately associated with these T cells. Moreover, 70% of T cells in the CNS were associated with single or clustered MHC class II+ microglia, and interacting cells were predominantly deep within the tissue parenchyme. Approximately 3.7% of the microglia that were freshly isolated from the GvHD-affected CNS were cycling, and proliferating cell nuclear Ag-positive microglia were detected in situ. Microglia from GvHD-affected animals sorted to purity by flow cytometry and cultured, extended long complex processes, exhibited spineous processes, and were phagocytic and highly motile. These outcomes are consistent with direct tissue macrophage-T cell interactions in situ that lead to activation, proliferation, and expansion of the responding tissue-resident cell.
Alternative Metabolic States in Murine Macrophages Reflected by the Nitric Oxide Synthase/Arginase Balance: Competitive Regulation by CD4+ T Cells Correlates with Th1/Th2 Phenotype
Authors: Munder Markus , Eichmann Klaus , Modolell Manuel 
Published: January 2023

Abstract
Activated murine macrophages metabolize l-arginine via two main pathways that are catalyzed by the inducible enzymes nitric oxide synthase (iNOS) and arginase. We have previously shown that CD4+ T cell-derived cytokines regulate a competitive balance in the expression of both enzymes in macrophages; Th1-type cytokines induce iNOS while they inhibit arginase, whereas the reverse is the case for Th2-type cytokines. Here we addressed the regulation of both metabolic pathways by CD4+ T cells directly. Macrophages were used as APCs for established Th1 and Th2 T cell clones as well as for in vitro polarized Th1 or Th2 T cells of transgenic mice bearing an MHC class II-restricted TCR. Both systems revealed a similar dichotomy in the macrophages; Th1 T cells led to an exclusive induction of iNOS, whereas Th2 T cells up-regulated arginase without inducing iNOS. Arginase levels induced by Th2 T cells far exceeded those inducible by individual Th2 cytokines. Similarly, high arginase levels could be induced by supernatants of Th2 cells stimulated in various ways. Ab blocking experiments revealed the critical importance of IL-4 and IL-10 for arginase up-regulation. Finally, strong synergistic effects between IL-4/IL-13 and IL-10 were observed, sufficient to account for the extraordinarily high arginase activity induced by Th2 cells. Our results suggest that the iNOS/arginase balance in macrophages is competitively regulated in the context of Th1- vs Th2-driven immune reactions, most likely by cytokines without the requirement for direct cell interaction.
IFN-γ Priming Up-Regulates IFN-Stimulated Gene Factor 3 (ISGF3) Components, Augmenting Responsiveness of IFN-Resistant Melanoma Cells to Type I IFNs
Authors: Wong Lee H. , Hatzinisiriou Irene , Devenish Rodney J. , Ralph Stephen J. 
Published: January 2023

AbstractIFN-stimulated gene factor 3 (ISGF3) mediates transcriptional activation of IFN-sensitive genes (ISGs). The component subunits of ISGF3, STAT1αβ, STAT2, and p48-ISGF3γ, are tyrosine phosphorylated before their assembly into a complex. Subsequently, the ISGF3 complex is translocated to the nucleus. We have recently established that the responsiveness of human melanoma cell lines to type I IFNs correlates directly with their intracellular levels of ISGF3 components, particularly STAT1. In the present study, we show that pretreating IFN-resistant melanoma cell lines with IFN-γ (IFN-γ priming) before stimulation with type I IFN also results in increased levels of ISGF3 components and enhanced DNA-binding activation of ISGF3. In addition, IFN-γ priming of IFN-resistant melanoma cell lines increased expression of type I IFN-induced ISG products, including ISG54, 2′-5′-oligoadenylate synthase, HLA class I, B7-1, and ICAM-1 Ags. Furthermore, IFN-γ priming enhanced the antiviral effect of IFN-β on the IFN-resistant melanoma cell line, MM96. These results support a role for IFN-γ priming in up-regulating ISGF3, thereby augmenting the responsiveness of IFN-resistant melanoma cell lines to type I IFN and providing a molecular basis and justification for using sequential IFN therapy, as proposed by others, to enhance the use of IFNs in the treatment of melanoma.
Heparin-Binding Protein (CAP37) Is Internalized in Monocytes and Increases LPS-Induced Monocyte Activation
Authors: Heinzelmann Michael , Mercer-Jones Mark A. , Flodgaard Hans , Miller Frederick N. 
Published: January 2023

AbstractPrevious studies have shown that the neutrophil-derived heparin-binding protein (HBP), also known as CAP37 or azurocidin, potentiates the LPS-induced release of proinflammatory cytokines (TNF-α, IL-1, and IL-6) from isolated human monocytes. To date, the mechanisms by which HBP enhances LPS-induced monocyte activation have not been elucidated, and it is not known whether HBP also increases the LPS-induced production of other bioactive substances. We studied human monocytes activated by recombinant human HBP and LPS and their interaction with the LPS receptor CD14. We hypothesized that the stimulatory effect of HBP on the LPS-induced release of proinflammatory mediators from monocytes was mediated by specific binding of HBP to monocytes, which resulted in an up-regulation of CD14. Our results demonstrated that HBP alone (10 μg/ml) stimulated the production of TNF-α from isolated monocytes. In addition, HBP had an additive effect on LPS-induced production of TNF-α and PGE2, suggesting a generalized monocyte activation. We used flow cytometry to demonstrate that HBP had a high affinity to monocytes but not to the LPS receptor CD14, and experiments performed at 4°C indicated an energy-dependent step in this process. Confocal microscopy showed that monocytes internalize HBP within 30 min. These data suggest that mechanisms other than increased CD14 expression are responsible for the enhanced release of TNF-α or PGE2 in response to HBP and LPS.
Soluble IL-15 Receptor α-Chain Administration Prevents Murine Collagen-Induced Arthritis: A Role for IL-15 in Development of Antigen-Induced Immunopathology
Authors: Ruchatz Holger , Leung Bernard P. , Wei Xiao-qing , McInnes Iain B. , Liew Foo Y. 
Published: January 2023

AbstractIL-15 has recently been detected in the synovium of patients with rheumatoid arthritis. IL-15-activated T cells induce significant TNF-α synthesis by macrophages via a cell contact-dependent mechanism, suggesting a key regulatory role for IL-15. Here, we report that the administration of a soluble fragment of IL-15Rα into DBA/1 mice, profoundly suppressed the development of collagen-induced arthritis. This was accompanied in vitro by marked reductions in Ag-specific proliferation and IFN-γ synthesis by spleen cells from treated mice compared with control mice and in vivo by a significant reduction in serum anti-collagen Ab levels. These data directly demonstrate a pivotal role for IL-15 in the development of inflammatory arthritis and also suggest that antagonists to IL-15 may have therapeutic potential in rheumatic diseases.
Thymus Requirement and Antigen Dependency in the “Infectious” Tolerance Pathway in Transplant Recipients
Authors: Onodera Kazuhiko , Volk Hans-Dieter , Ritter Thomas , Kupiec-Weglinski Jerzy W. 
Published: January 2023

AbstractWe have shown that features of infectious tolerance, as originally described in thymectomized mice, may be applied to euthymic rat recipients of heart transplants. We now report on studies aimed at exposing mechanisms underlying the infectious tolerance pathway, with emphasis on the role of thymus and alloantigen. Pretransplant thymectomy diminished the efficacy of CD4-targeted therapy, with donor-specific tolerance induced in ∼50% of recipients. Thymus was required for generation of regulatory T cells under the cover of CD4 mAb therapy and for the ability of these cells to confer infectious tolerance. However, thymus was not mandatory to maintain an infectious-permissive environment in cohorts of adoptively transferred recipients. Intragraft expression of IL-2, IL-4, and IL-10 genes was diminished in euthymic and thymectomized tolerant hosts. However, grafts in the latter group showed significant IFN-γ gene expression, suggesting a less efficient down-regulation of Th1-like cells in the absence of regulatory cells. Indeed, exogenous challenge with rIL-2 or freshly alloactivated spleen cells recreated rejection in thymectomized, but not euthymic, hosts, suggesting that a state of cytokine-responsive anergy contributes to the “noninfectious” form of tolerance in thymectomized rats. The infection-tolerant state did not result from “graft adaptation,” and regulatory T cells restricted for the original alloantigen were exposed to its continuous stimulation. The effective memory for suppression was dependent upon persistent donor-specific alloantigen stimulation; it disappeared within 3 weeks after its removal. Hence, both central and peripheral immune mechanisms, orchestrated by the tolerizing alloantigen, contribute to the infectious tolerance pathway in CD4 mAb-treated rat transplant recipients.
Cooperation Between CD44 and LFA-1/CD11a Adhesion Receptors in Lymphokine-Activated Killer Cell Cytotoxicity
Authors: Matsumoto Goichi , Nghiem Mai P. , Nozaki Naohito , Schmits Rudolf , Penninger Josef M. 
Published: January 2023

AbstractIL-2-activated NK cells exhibit cytotoxic activity against a wide variety of tumor cells in a non-MHC-restricted fashion and in the absence of prior sensitization. The molecular mechanisms that regulate the cytotoxicity and attachment of activated killer cells to tumor target cells are not known. We provide genetic evidence in CD44−/− and LFA-1−/− mice that the cell adhesion receptors LFA-1 and CD44 regulate the cytotoxic activity of IL-2-activated NK cells against a variety of different tumor cells. This defect in cytotoxicity was significantly enhanced in mice that carried a double mutation of both CD44 and LFA-1. In vitro differentiation, TNF-α and IFN-γ production, and expression of the cytolytic effector molecules perforin and Fas-L were comparable among IL-2-activated NK cells from LFA-1−/−, CD44−/−, CD44−/−LFA-1−/−, and control mice. However, CD44−/−, LFA-1−/−, and CD44−/−LFA-1−/− IL-2-activated NK cells showed impaired binding and conjugate formation with target cells. We also show that hyaluronic acid is the principal ligand on tumor cells for CD44-mediated cytotoxicity of IL-2-activated NK cells. These results provide the first genetic evidence of the role of adhesion receptors in IL-2-activated NK killing. These data also indicate that distinct adhesion receptors cooperate to mediate binding between effector and target cells required for the initiation of “natural” cytotoxicity.
Dissection of Pathways Leading to Antigen Receptor-Induced and Fas/CD95-Induced Apoptosis in Human B Cells
Authors: Lens Susanne M. A. , den Drijver Bianca F. A. , Pötgens Andy J. G. , Tesselaar Kiki , van Oers Marinus H. J. , van Lier René A. W. 
Published: January 2023

AbstractTo dissect intracellular pathways involved in B cell Ag receptor (BCR)-mediated and Fas-induced human B cell death, we isolated clones of the Burkitt lymphoma cell line Ramos with different apoptosis sensitivities. Selection for sensitivity to Fas-induced apoptosis also selected for clones with enhanced BCR death sensitivity and vice versa. In contrast, clones resistant to Fas-mediated apoptosis could still undergo BCR-induced cell death. Based on the functional phenotypes of these clones, we hypothesized that both receptor-induced apoptosis pathways are initially distinct but may eventually converge. Indeed, ligation of both Fas and BCR resulted in cleavage of the IL-1β-converting enzyme/Ced-3-like protease caspase 3 and its substrates Ac-Asp-Glu-Val-Asp-aldehyde and poly(ADP-ribose) polymerase. Markedly, qualitative differences in the caspase 3 cleavage pattern induced by Fas or BCR ligation were observed; whereas Fas ligation generated caspase 3 cleavage products of 19/20 and 17 kDa, only the latter cleavage product was found upon BCR cross-linking. The caspase inhibitor Val-Ala-Asp-fluoromethylketone blocked both Fas- and BCR-mediated apoptosis, but differentially affected caspase 3 cleavage induced by either stimulus. Finally, overexpression of a Fas-associated death domain (FADD) dominant-negative mutant protein was found to inhibit Fas-induced apoptosis but not BCR-induced apoptosis. Together our findings imply that Fas and BCR couple, via FADD-dependent and FADD-independent mechanisms, respectively, to distinct proteases upstream of caspase 3.
Arachidonic Acid Enhances the Tissue Factor Expression of Mononuclear Cells by the Cyclo-Oxygenase-1 Pathway: Beneficial Effect of n-3 Fatty Acids
Authors: Cadroy Yves , Dupouy Dominique , Boneu Bernard 
Published: January 2023

Abstract
Monocytes express tissue factor (TF) upon stimulation by inflammatory agents. Dietary administration of fish oil rich in eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) results in an impairment of TF expression by monocytes. EPA and DHA are metabolized differently from arachidonic acid (AA), the major fatty acid present in cell membranes. We examined the effects of AA on the TF expression of isolated human PBMC, and we determined whether EPA and DHA modulated this phenomenon differently. Nonstimulated PBMC had a low TF-dependent procoagulant activity. When PBMC were incubated with increasing concentrations of AA, the TF-dependent procoagulant activity increased in a dose-dependent manner to 190% at 7.5 μM. Indomethacin, a cyclo-oxygenase inhibitor, totally abolished the stimulating effect of AA, whereas specific pharmacologic inhibitors of cyclo-oxygenase-2 or of 5-lipoxygenase had no inhibitory effect. A thromboxane (TX)A2/endoperoxides receptor antagonist and a TX synthase inhibitor blocked the potentiating effect of AA. Purified PGG2 and carbocyclic TXA2, a TXA2 agonist, enhanced the procoagulant activity of PBMC in a dose-dependent manner whereas, in contrast, PGE2 inhibited it. Finally, contrary to AA, EPA or DHA did not increase TXB2 production or TF expression by PBMC. The TF-dependent procoagulant activity of isolated PBMC was increased by AA through the production of cyclo-oxygenase-1 metabolites; the combined action of PGG2 and TXA2, which potentiated it, was greater than that of PGE2, which inhibited it. Dietary n-3 fatty acids exert part of their beneficial effect by modulating this procoagulant activity differently from AA.
T Helper 1 Response Is Dominant and Localized to the Synovial Fluid in Patients with Lyme Arthritis
Authors: Gross Dawn M. , Steere Allen C. , Huber Brigitte T. 
Published: January 2023

Abstract
Cytokines produced by subsets of CD4+ T helper cells responding to an infection influences the efficiency with which the host is able to mount a protective immune response. In an attempt to elucidate the population of active cells involved in the propagation of Lyme arthritis we have utilized intracellular cytokine staining to analyze the polyclonal immune response at the single cell level. We have determined the Th phenotype in the synovial fluid of patients with a variety of chronic inflammatory arthritides, including patients representative of the spectrum of Lyme arthritis. Th1 cells dominate the immune response in the synovial fluid of patients with Lyme as well as those with rheumatoid or other types of chronic inflammatory arthritis. In addition, the severity of Lyme arthritis directly correlates with the ratio of Th1 to Th2 cells in the synovial fluid, such that the larger the effusion, the higher the ratio (r = 0.67, p &lt; 0.05). These results suggest that Th1 cells play a direct role in the pathogenesis of the inflammatory process seen in Lyme arthritis, and that Th2 cells modulate the pro-inflammatory response generated by Th1 cells in the joint. Finally, we identify Th1 cells specific for outer surface protein A of Borrelia burgdorferi, the agent of Lyme disease. These cells are restricted to patients with Lyme arthritis and are localized to the joint. Furthermore, they persist in patients with prolonged antibiotic treatment-resistant Lyme arthritis, suggesting the possibility of an autoimmune process.
Activation of STAT5 by Lipopolysaccharide Through Granulocyte-Macrophage Colony-Stimulating Factor Production in Human Monocytes
Authors: Yamaoka Kunihiro , Otsuka Takeshi , Niiro Hiroaki , Arinobu Yojiro , Niho Yoshiyuki , Hamasaki Naotaka , Izuhara Kenji 
Published: January 2023

Abstract
LPS is a potent stimulator of monocytes, inducing many of their functions. Although the details of how LPS exerts such functions remain largely unknown, transcription factors such as nuclear factor-κB, nuclear factor-IL-6, and activator protein-1 have been shown to be involved in this process. However, to date it has been thought that no known STAT molecule plays a role in the activation of monocytes by LPS. In this study we examined whether some known STAT molecule is stimulated by LPS, based on the finding that a GAS motif sequence is conserved in the promoter regions of human, mouse, and rat cyclo-oxygenase-2 (COX-2) genes. Consequently, LPS induced activation of STAT5 in human monocytes, and this STAT5 activation occurred in an indirect way via granulocyte-macrophage CSF (GM-CSF) secreted by LPS-stimulated monocytes. Expression of COX-2 protein was partially reduced by treatment of anti-human GM-CSF Ab. Activation of STAT5 was inhibited by either IL-10 or dexamethasone (Dex), but not by aspirin. IL-10 blocked activation of STAT5 indirectly by suppressing GM-CSF production, while Dex inhibited this activation both directly and indirectly. Taken together, these results suggest that in addition to other transcription factors, STAT5 plays an important role in activation of monocytes by LPS, and that STAT5 is another target for IL-10 and Dex to inhibit COX-2 expression in activated monocytes.
Perforin-Deficient CD8+ T Cells Provide Immunity to Listeria monocytogenes by a Mechanism That Is Independent of CD95 and IFN-γ but Requires TNF-α
Authors: White Douglas W. , Harty John T. 
Published: January 2023

Abstract
CD8+ T cells are effective mediators of immunity against Listeria monocytogenes, but the mechanisms by which they provide antilisterial immunity are poorly understood. CD8+ T cells efficiently lyse target cells in vitro by at least two independent pathways. To test the hypothesis that CD8+ T cell-mediated immunity to L. monocytogenes is dependent on perforin or CD95 (Fas, Apo-1), we used C57Bl/6 (B6) and perforin-deficient (PO) mice to generate CD8+ T cell lines specific for the L. monocytogenes-encoded Ag listeriolysin O (LLO). Both lines specifically produce IFN-γ and TNF-α, and mediate target cell lysis in vitro. Cytolysis mediated by the PO-derived CD8+ T cell line is delayed relative to the B6-derived line and is completely inhibited by anti-CD95 Abs. In vivo, PO-derived CD8+ T cells provide specific antilisterial immunity in B6 hosts, CD95-deficient hosts, and IFN-γ-depleted hosts. However, PO-derived CD8+ T cells fail to provide antilisterial immunity in hosts depleted of TNF-α. These results indicate that single Ag-specific CD8+ T cells derived from PO mice can mediate antilisterial immunity by a mechanism that is independent of CD95 or IFN-γ, but requires TNF-α.