bluuebunny/crossref_metadata_2025_split huggingface dataset:
Murine IgG1 Complexes Trigger Immune Effector Functions Predominantly via FcγRIII (CD16)
Authors: Hazenbos Wouter L. W. , Heijnen Ingmar A. F. M. , Meyer Dirk , Hofhuis Frans M. A. , Renardel de Lavalette Chantal , Schmidt Reinhold E. , Capel Peter J. A. , van de Winkel Jan G. J. , Gessner J. Engelbert , van den Berg Timo K. , Verbeek J. Sjef 
Published: December 2022

AbstractPreviously, we have demonstrated that phagocytosis of IgG1-coated particles by macrophages in vitro is impaired by deletion of FcγRIII in mice, suggesting that IgG1 may interact preferentially with FcγRIII. In the present study, the biologic relevance of this observation was addressed by triggering various effector functions of the immune system in FcγRIII−/− mice, using panels of mAbs of different IgG subclasses. Both binding and phagocytosis of IgG1-coated sheep or human erythrocytes by FcγRIII−/− macrophages in vitro were strongly impaired, indicating that the impaired ingestion of complexed IgG1 by FcγRIII−/−macrophages is due to a defect in binding. An in vivo consequence of the defective phagocytosis was observed by resistance of FcγRIII-deficient mice to experimental autoimmune hemolytic anemia, as shown by a lack of IgG1-mediated erythrophagocytosis in vivo by liver macrophages. Furthermore, trapping of soluble IgG1-containing immune complexes by follicular dendritic cells in mesenteric lymph nodes from FcγRIII−/− mice was abolished. Whole blood from FcγRIII−/− mice was unable to induce lysis of tumor cells in the presence of IgG1 antitumor Abs. Finally, IgG1 mAbs proved unable to mount a passive cutaneous anaphylaxis in FcγRIII−/− mice. Together, these results demonstrate that IgG1 complexes, either in particulate or in soluble form, trigger in vitro and in vivo immune effector functions in mice predominantly via FcγRIII.
CXCR4 and CCR5 on Human Thymocytes: Biological Function and Role in HIV-1 Infection
Authors: Zaitseva Marina B. , Lee Shirley , Rabin Ronald L. , Tiffany H. Lee , Farber Joshua M. , Peden Keith W. C. , Murphy Philip M. , Golding Hana 
Published: December 2022

Abstract
Thymocyte infection with HIV-1 is associated with thymic involution and impaired thymopoiesis, particularly in pediatric patients. To define mechanisms of thymocyte infection, we examined human thymocytes for expression and function of CXCR4 and CCR5, the major cell entry coreceptors for T cell line-tropic (T-tropic) and macrophage-tropic (M-tropic) strains of HIV-1, respectively. CXCR4 was detected on the surface of all thymocytes. CXCR4 expression on mature, high level TCR thymocytes was similar to that on peripheral blood T cells, but was much lower than that on immature thymocytes, including CD34+ thymic progenitors. Consistent with this, stroma-derived factor-1 (SDF-1) induced calcium flux primarily in immature thymocytes, with CD34+ progenitors giving the strongest response. In addition, SDF-1 mRNA was detected in thymic-derived stromal cells, and SDF-1 induced chemotaxis of thymocytes, suggesting that CXCR4 may play a role in thymocyte migration. Infection of immature thymocytes by the T-tropic HIV-1 strain LAI was 10-fold more efficient than that in mature thymocytes, consistent with their relative CXCR4 surface expression. Anti-CXCR4 antiserum or SDF-1 blocked fusion of thymocytes with cells expressing the LAI envelope. In contrast to CXCR4, CCR5 was detected at low levels on thymocytes, and CCR5 agonists did not induce calcium flux or chemotaxis in thymocytes. However, CD4+ mature thymocytes were productively infected with the CCR5-tropic strain Ba-L, and this infection was specifically inhibited with the CCR5 agonist, macrophage inflammatory protein-1β. Our data provide strong evidence that CXCR4 and CCR5 function as coreceptors for HIV-1 infection of human thymocytes.
Signaling Through a CD3γ-Deficient TCR/CD3 Complex in Immortalized Mature CD4+ and CD8+ T Lymphocytes
Authors: Pacheco-Castro Alberto , Alvarez-Zapata David , Serrano-Torres Pilar , Regueiro José R. 
Published: December 2022

AbstractThe biologic role of each CD3 chain and their relative contribution to the signals transduced through the TCR/CD3 complex and to downstream activation events are still controversial: they may be specialized or redundant. We have immortalized peripheral blood CD4+ and CD8+ T lymphocytes from a human selective CD3γ deficiency using Herpesvirus saimiri. The accessibility of the mutant TCR/CD3 complex to different Abs was consistently lower in immortalized CD8+ cells when compared with CD4+ cells, relative to their corresponding CD3γ-sufficient controls. Several TCR/CD3-induced downstream activation events, immediate (calcium flux), early (cytotoxicity and induction of surface CD69 or CD40L activation markers or intracellular TNF-α) and late (proliferation and secretion of TNF-α), were normal in γ-deficient cells, despite the fact that their TCR/CD3 complexes were significantly less accessible than those of controls. In contrast, the accumulation of intracellular IL-2 or its secretion after CD3 triggering was severely impaired in γ-deficient cells. The defect was upstream of protein kinase C activation because addition of transmembrane stimuli (PMA plus calcium ionophore) completely restored IL-2 secretion in γ-deficient cells. These results suggest that the propagation of signals initiated at the TCR itself can result in a modified downstream signaling cascade with distinct functional consequences when γ is absent. They also provide evidence for the specific participation of the CD3γ chain in the induction of certain cytokine genes in both CD4+ and CD8+ human mature T cells. These immortalized mutant cells may prove to be useful in isolating cytosolic signaling pathways emanating from the TCR/CD3 complex.
SLP-76 Expression Is Restricted to Hemopoietic Cells of Monocyte, Granulocyte, and T Lymphocyte Lineage and Is Regulated During T Cell Maturation and Activation
Authors: Clements James L. , Ross-Barta Susan E. , Tygrett Lorraine T. , Waldschmidt Thomas J. , Koretzky Gary A. 
Published: December 2022

AbstractThe leukocyte-specific adapter protein SLP-76 is known to augment the transcriptional activity of nuclear factor of activated T cells and AP-1 following TCR ligation. A role for SLP-76 in additional receptor-mediated signaling events is less clear. To define the pattern of SLP-76 expression during murine hemopoiesis, we stained cells isolated from various tissues with a combination of surface markers followed by intracellular staining with a fluorochrome-labeled SLP-76-specific Ab. In the bone marrow, SLP-76 expression is largely restricted to cells of granulocyte and monocyte lineage. Heterogeneous SLP-76 expression is first detected in the CD44+CD25− subset within the CD3−CD4−CD8− thymocyte population. Interestingly, SLP-76 expression increases as thymocyte maturation progresses within the CD4−CD8− compartment but decreases as cells mature to a CD4+CD8+ phenotype. SLP-76 expression is then up-regulated following selection and concomitant with maturation to a CD4+ or CD8+ phenotype. In the periphery, SLP-76 is expressed in T lymphocytes with no detectable expression in the B cell compartment. Exposure to the superantigen staphylococcal enterotoxin B augments SLP-76 expression in the reactive T cell subset. Furthermore, in vitro stimulation with TCR-specific Abs augments the existing levels of SLP-76. These data reveal that SLP-76 expression is coordinately regulated with surface expression of a pre-TCR or mature TCR complex during thymocyte development and that TCR ligation elicits signals that result in increased expression of SLP-76.
Effects of Bacterial DNA on Cytokine Production by (NZB/NZW)F1 Mice
Authors: Gilkeson Gary S. , Conover Jacqueline , Halpern Melissa , Pisetsky David S. , Feagin Amy , Klinman Dennis M. 
Published: December 2022

AbstractMicrobial DNA has multiple immune effects including the capacity to induce polyclonal B cell activation and cytokine production in normal mice. We recently described the accelerated induction of anti-DNA Abs in NZB/NZW mice immunized with Escherichia coli (EC) dsDNA; paradoxically these mice developed less renal disease than unimmunized mice or mice immunized with calf thymus DNA. We postulated that alterations in cytokine production induced by bacterial DNA may play a key role in renal protection. To determine the effect of bacterial DNA on cytokine production in NZB/NZW mice, we measured the serum cytokine levels, cell culture supernatant cytokine levels, and number of cytokine-producing splenocytes in NZB/NZW mice injected with EC DNA, calf thymus DNA, or an immune active oligonucleotide. There was a 10- to 25-fold increase in the number of cells secreting IFN-γ compared with IL-4 in mice immunized with EC DNA. IL-12-secreting cells were also increased by bacterial DNA immunization. In parallel with the increase in IFN-γ secreting cells, there was a significant rise in serum IFN-γ levels in mice receiving EC DNA. These results indicate that EC DNA modulates systemic cytokine levels in NZB/NZW mice, selectively increasing IL-12 and IFN-γ while decreasing IL-4 production. The cytokine response of NZB/NZW mice to bacterial DNA may be of significance in disease pathogenesis and relevant to the treatment of lupus-like disease.
Development of Peptide-Selected CD8 T Cells in Fetal Thymic Organ Culture Occurs via the Conventional Pathway
Authors: Hogquist Kristin A. , Bonnevier Jody L. 
Published: December 2022

AbstractFetal thymic organ culture of TCR transgenic (Tg) tissue has been used to study issues of timing and specificity in T cell development. Because most TCR Tgs express a rearranged αβ TCR on the cell surface at an earlier stage in development than normal mice, there is a possibility that the conclusions of studies using TCR Tg cultures may not apply to normal development. In particular, in our studies of peptide-induced development of CD8 T cells, it is possible that the peptide acts on the immature double-negative cell, driving development of CD8 T cells without passing through a double-positive stage. This issue was examined by asking whether MHC class I restriction was required and by analyzing CD8β levels and endogenous TCRα chain rearrangements. We found that if nonstimulatory peptides were used in fetal thymic organ culture, CD8 T cells developed via the conventional pathway, transiting through a double-positive stage. However, we could not rule out that cells selected in the presence of stimulatory peptides (agonists) did not develop directly from double-negative precursors.
Positive and Negative Regulation of Human T Cell Activation Mediated by the CTLA-4/CD28 Ligand CD80
Authors: Boulougouris George , McLeod Julie D. , Patel Yusuf I. , Ellwood Claire N. , Walker Lucy S. K. , Sansom David M. 
Published: December 2022

AbstractCD28 and CTLA-4 are related receptors that differentially regulate T cell activation. Despite the fact that they bind the same ligands, CD28 is a classical costimulator enhancing proliferation whereas CTLA-4 appears to perform negative regulatory functions. In this study, we have utilized the natural ligand for CD28 and CTLA-4 (CD80) to determine under what circumstances positive and negative effects are operative. We show here that the stimulation of purified human T cells with phorbol ester and ionomycin is inhibited in the presence of Chinese hamster ovary (CHO) cells expressing CD80. This inhibition is reversed by blocking with both anti-CD80 or Fab fragments of anti-CTLA-4 but also requires CD28 engagement. Furthermore, we show that the inhibitory function of CD80 requires elevated intracellular calcium since inhibition was observed only in the presence of ionomycin. In the absence of intracellular calcium elevation, CTLA-4 was not expressed at the cell surface, and CD80 acted positively as a costimulator of T cells, via CD28. These results demonstrate that the natural ligand CD80 can either costimulate or inhibit T cell responses depending on the conditions of T cell stimulation.
Initiation of the Autologous Mixed Lymphocyte Reaction Requires the Expression of Costimulatory Molecules B7-1 and B7-2 on Human Peripheral Blood Dendritic Cells
Authors: Scheinecker Clemens , Machold Klaus P. , Majdic Otto , Höcker Paul , Knapp Walter , Smolen Josef S. 
Published: December 2022

AbstractThe human autologous mixed lymphocyte reaction (AMLR) consists of a proliferative response of primarily CD4+ T lymphocytes stimulated by autologous non-T cells expressing class II MHC-encoded gene products and is thought to represent a self-recognitive mechanism that might be important in regulating the cellular interactions involved in the generation of normal immune responses. To further define appropriate stimulator cell populations, as well as the molecular mechanism responsible for the initiation of AMLR, we compared the T cell-stimulatory capacity of highly purified populations of peripheral blood dendritic cells (DCs) and monocytes (Mos) under serum-free conditions, thus carefully avoiding the presence of xenogeneic Ags. Whereas both freshly isolated Mos and DCs were found to be poor stimulators of autologous T cell proliferation, preactivation of DCs, but not of Mos, for 48 h with granulocyte-macrophage CSF led to a 113-fold increase in DC stimulatory capacity. AMLR was inhibited by mAbs against HLA-DR and CD4 molecules, and, in addition, showed a higher dependence on the granulocyte-macrophage CSF-induced up-regulation and/or de novo expression of the costimulatory molecules B7-2 and, in particular, B7-1 as compared with an Ag-specific or allogeneic MLR. Thus, our data suggest that the high density of costimulatory molecules together with MHC class II molecules on competent APCs appear to be the major triggers for the initiation of AMLR.
Deletion of Bone Marrow Stromal Cell Antigen-1 (CD157) Gene Impaired Systemic Thymus Independent-2 Antigen-Induced IgG3 and Mucosal TD Antigen-Elicited IgA Responses
Authors: Itoh Motoyuki , Ishihara Katsuhiko , Hiroi Takachika , Ok Lee Byung , Maeda Hisoka , Iijima Hideki , Yanagita Manabu , Kiyono Hiroshi , Hirano Toshio 
Published: December 2022

AbstractBone marrow stromal cell Ag-1 (BST-1; CD157)-deficient mice were generated to examine the immunologic roles of the molecule in vivo. In BST-1−/− mice, the development of peritoneal B-1 cells was delayed, and CD38low/− B-lineage cells were increased in the bone marrow and spleen. Partial impairment of thymus-independent (TI-2) and thymus-dependent (TD) Ag-specific immune responses was noted in the systemic and mucosal compartments of BST-1−/− mice, respectively. Although serum Ig levels as well as TD and TI-1 Ag-specific systemic immune responses were normal, the TI-2 Ag-induced IgG3 response was selectively impaired. Oral immunization of BST-1−/− mice with cholera toxin, a potent TD Ag for the induction of IgA response, resulted in the poor production of Ag-specific Abs at the intestinal mucosa accompanied by the reduced number of Ag-specific IgA-producing cells in the lamina propria. These results indicate that BST-1 has roles in B cell development and Ab production in vivo.
Lipid Vesicle Size Determines the Th1 or Th2 Response to Entrapped Antigen
Authors: Brewer James M. , Tetley Laurence , Richmond James , Liew Foo Y. , Alexander James 
Published: December 2022

AbstractUnderstanding the factors that control the differential induction of Th1 and Th2 responses is a key immunologic objective with profound implications for vaccination and immunotherapy of infectious and autoimmune diseases. Using Ag formulated in lipid vesicles prepared from nonionic surfactants, we describe a novel mechanism influencing the balance of the Th1 or Th2 response. Our results indicate that inoculation of BALB/c mice with vesicles with a mean diameter ≥225 nm preferentially induces Th1 responses, as characterized by increased titers of IgG2a in plasma and elevated IFN-γ production by lymph node cells. However, preparation of the same quantity of Ag in vesicles with mean diameter of ≤155 nm induces a Th2 response, as identified by IgG1 in the absence of IgG2a production and increased lymph node IL-5 production. Although large (≥225 nm) vesicles could induce IL-12 production, smaller vesicles (≤155 nm) could not. However, small vesicles did induce higher levels of IL-1β production by macrophages than larger vesicles. The role of IL-12 in this response was confirmed in IL-12-deficient mice, whose spleen cells failed to produce IFN-γ following in vivo priming with Ag prepared in large vesicles. Our results therefore indicate that macrophages respond to endocytosis of large or small vesicles by producing different patterns of cytokines that can subsequently direct the immune response toward a Th1 or a Th2 phenotype.
The Role of Ets-1 in Mast Cell Granulocyte-Macrophage Colony-Stimulating Factor Expression and Activation
Authors: McKinlay Leigh H. , Tymms Martin J. , Thomas Ross S. , Seth Arun , Hasthorpe Suzanne , Hertzog Paul J. , Kola Ismail 
Published: December 2022

AbstractEts-1 is a transcription factor with restricted expression in lymphocytes, and it has been implicated in the regulation of T cell genes such as TCRα, TCRβ, CD4, IL-2, and TNF-α. We show in this study that Ets-1 is also expressed in some mast cells constitutively and can be induced in primary mast cells with stimuli that activate mast cells. We also show that Ets-1 plays a role in the regulation of granulocyte-macrophage CSF (GM-CSF), a cytokine expressed by activated mast cells. We have characterized a murine growth factor-independent mast cell line, FMP6−, derived from a factor-dependent cell line, FMP1.6. FMP6− has acquired a distinct connective tissue mast cell-like phenotype, as characterized by the expression of mast cell proteases MMCP-4 and MMCP-6, expression of IL-12, and the down-regulation of IL-4. The parental FMP1.6 cell line displays a mucosal mast cell-like phenotype. FMP6− cells have increased Ets-1 expression and achieve growth-factor independence by the autocrine production of GM-CSF and IL-3. Transient transfection of an Ets-1 expression construct in FMP6− cells results in transactivation of a GM-CSF reporter, while a point mutation in the consensus Ets binding site in the conserved lymphokine element, CLE0, abolishes Ets-1 transactivation. Importantly, antisense Ets-1 demonstrates an ability to repress the activity of the GM-CSF reporter. These data suggest a role for Ets-1 in mast cell growth regulation and activation, and because of the central role of mast cells in inflammatory processes, such as asthma and rheumatoid arthritis, they identify Ets-1 as potentially contributing to the pathophysiology of such diseases.
Nitric Oxide Prevents IL-1β and IFN-γ-Inducing Factor (IL-18) Release from Macrophages by Inhibiting Caspase-1 (IL-1β-Converting Enzyme)
Authors: Kim Young-Myeong , Talanian Robert V. , Li Jianrong , Billiar Timothy R. 
Published: December 2022

Abstract
Procytokine processing by caspase-1 is required for the maturation and release of IL-1β and IFN-γ-inducing factor (IGIF) (or IL-18) from activated macrophages (Mφ). Nitric oxide (NO) has emerged as a potent inhibitor of cysteine proteases. Here, we tested the hypothesis that NO regulates cytokine release by inhibiting IL-1β-converting enzyme (ICE) or caspase-1 activity. Activated RAW264.7 cells released four to five times more IL-1β, but not TNF-α, in the presence of the NO synthase inhibitor NG-monomethyl-l-arginine. Stimulated peritoneal Mφ from wild-type mice (inducible NO synthase (iNOS)+/+) also released more IL-1β if exposed to NG-monomethyl-l-arginine, whereas Mφ from iNOS knockout mice (iNOS−/−) did not. Inhibition of NO synthesis in stimulated RAW264.7 cells also resulted in a threefold increase in intracellular caspase-1 activity. The NO donor S-nitroso-N-acetyl-dl-penicillamine inhibited caspase-1 activity in cells as well as the activity of purified recombinant caspase-1 and also prevented the cleavage of pro-IL-1β and pro-IGIF by recombinant caspase-1. The inhibition of caspase-1 by NO was reversible by the addition of DTT, which is consistent with S-nitrosylation as the mechanism of caspase-1 inhibition. An in vivo role for the regulation of caspase-1 by NO was established in iNOS knockout animals, which exhibited significantly higher plasma levels of IL-1β and IFN-γ than their wild-type counterparts at 10 h following LPS injection. Taken together, these data indicate that NO suppresses IL-1β and IGIF processing by inhibiting caspase-1 activity, providing evidence for a unique role for induced NO in regulating IL-1β and IGIF release.
Down-Regulation of Tumoricidal NK and NK T Cell Activities by MHC Kb Molecules Expressed on Th2-Type γδ T and αβ T Cells Coinfiltrating in Early B16 Melanoma Lesions
Authors: Seo Naohiro , Tokura Yoshiki , Furukawa Fukumi , Takigawa Masahiro 
Published: December 2022

AbstractWe examined whether γδ T and αβ T cells accumulating in early B16 melanoma lesions regulate NK and NK T cells that attack tumor cells. Freshly isolated and cultured tumor-infiltrating lymphocyte (TIL) populations of NK and NK T cells lysed B16 and produced IFN-γ, whereas γδ T and a large part of αβ T cell populations had no substantial cytotoxicity against B16 and secreted Th2 cytokines. Furthermore, the freshly isolated NK1.1+ TIL population exhibited a higher anti-B16 effect than did splenocytes. γδ T and αβ T cell populations dramatically inhibited the cytotoxicity of NK and NK T cells in an MHC Kb-dependent manner. Culture supernatant from γδ T and αβ T cell populations inhibited the proliferation of NK and NK T cell populations but did not affect their cytotoxicity, suggesting that the released Th2 cytokines are merely partly involved in the down-modulation of NK-lineage cells. NK1.1+ cells obtained from TIL of γδ T cell-depleted mice significantly lysed B16 cells compared with those from control mice. Finally, anti-Kb Fab mAb injected intralesionally at an early, but not at a late, stage of development of B16 melanoma inhibited tumor growth. These findings suggest that Th2-type γδ T and αβ T cells infiltrating in early B16 development inhibit the tumoricidal activity of NK-lineage cells using their class I molecules and partly their suppressive cytokines.
Thymic Expression of the Transcription Factor Nur77 Rescues the T Cell But Not the B Cell Abnormality of gld/gld Mice
Authors: Chan Francis Ka-Ming , Astar Winoto Ann Chen 
Published: December 2022

Abstract
Fas and Fas ligand are critical regulators of lymphocyte homeostasis. Disruption of this pathway in the spontaneous mouse mutant gld leads to autoimmunity characterized by the appearance of a population of CD4−8−B220+ T cells and the production of autoantibodies. Nur77 is a transcription factor that is induced upon TCR signaling. Constitutive thymic expression of Nur77 leads to apoptosis. We have previously shown that introduction of this Nur77 transgene can eliminate the accumulation of abnormal T cells in the periphery of gld/gld mice. In this report, we further characterized the effects of the Nur77 transgene on the gld phenotype. Nur77-mediated apoptosis is evident in the thymuses of mice with either a gld/gld homozygous or gld/+ heterozygous background. Consequently, few mature T cells are generated in these mice. In addition, mature T cells exhibit a diminished response to proliferative signals through CD3. Interestingly, the Nur77 transgene failed to reduce serum levels of Igs and anti-DNA Abs to wild-type levels. These data suggest that the rescue of the T cell lymphoproliferative syndrome in gld/gld mice by the Nur77 transgene is mediated by events in the thymus and that B cell autoimmune disease associated with the gld mutation can develop independently of the T cell abnormality.