bluuebunny/crossref_metadata_2025_split huggingface dataset:
Monoclonal Origin of Concordant T-Cell Malignancy in Identical Twins
Authors: Ford Anthony M. , Pombo-de-Oliveira Maria S. , McCarthy Keith P. , MacLean James M. , Carrico Kadma C. , Vincent Roberto F. , Greaves Mel 
Published: October 2019

AbstractAcute leukemia has a high concordance rate in young identical twins and in infants this is known, from molecular analysis, to reflect an in utero origin in one twin followed by prenatal metastasis to the other twin via intraplacental anastomoses. The situation in older twins with leukemia has been less clear. We describe a pair of identical twins who were diagnosed with a T-cell malignancy at 9 and 11 years of age, one with T-cell non-Hodgkin's lymphoma and the other with T-cell acute lymphoblastic leukemia. Leukemic cells from the twins shared the same TCRβ gene rearrangement with an identical 11 bp N region. The most plausible interpretation of this result is that these malignancies were initiated in one twin fetus in utero, in a single T-lineage cell that had stable bi-allelic TCRβ rearrangements. Progeny of this cell then spread to the other twin before birth via shared placental vasculature. This was then followed by a 9- and 11-year preleukemic latent period before clinical disease manifestation as leukemia or lymphoma. This result has considerable implications for the etiology and natural history of pediatric leukemia.
Engagement of the Lewis X Antigen (CD15) Results in Monocyte Activation
Authors: Lo Siu K. , Golenbock Douglas T. , Sass Philip M. , Maskati Azmat , Xu Hong , Silverstein Roy L. 
Published: October 2019

AbstractWe previously reported that monocyte adhesion to tumor necrosis factor-α (TNF-α)–treated endothelial cells increased expression of tissue factor and CD36 on monocytes. Using immunological cross-linking to mimic receptor engagement by natural ligands, we now show that CD15 (Lewis X), a monocyte counter-receptor for endothelial selectins may participate in this response. We used cytokine production as a readout for monocyte activation and found that CD15 cross-linking induced TNF-α release from peripheral blood monocytes and cells from the monocytic cell line MM6. Quantitative reverse transcriptase-polymerase chain reaction (RT-PCR) showed an increase in steady-state TNF-α mRNA after 3 to 4 hours of cross-linking. CD15 cross-linking also concomitantly increased interleukin-1β (IL-1β) mRNA, while no apparent change was observed in the levels of β-actin mRNA, indicating specificity. To examine transcriptional regulation of cytokine genes by CD15 engagement, a CAT plasmid reporter construct containing IL-1β promoter/enhancer sequences was introduced into MM6. Subsequent cross-linking of CD15 increased CAT activity. CD15 engagement by monoclonal antibody also attenuated IL-1β transcript degradation, demonstrating that signaling via CD15 also had posttranscriptional effects. Nuclear extracts of anti-CD15 cross-linked cells demonstrated enhanced levels of the transcriptional factor activator protein-1, minimally changed nuclear factor-κB, and did not affect SV40 promoter specific protein-1. We conclude that engagement of CD15 on monocytes results in monocyte activation. In addition to its well-recognized adhesive role, CD15 may function as an important signaling molecule capable of initiating proinflammatory events in monocytes that come into contact with activated endothelium.
Modulation of Calcium Channels in Human Erythroblasts by Erythropoietin
Authors: Cheung Joseph Y. , Zhang Xue-Qian , Bokvist Krister , Tillotson Douglas L. , Miller Barbara A. 
Published: October 2019

AbstractErythropoietin (Epo) induces a dose-dependent increase in intracellular free Ca2+ ([Ca2+]i ) in human erythroblasts, which is dependent on extracellular Ca2+ and blocked by high doses of nifedipine or Ni2+. In addition, pretreatment of human erythroblasts with mouse antihuman erythropoietin receptor antibody but not mouse immunopure IgG blocked the Epo-induced [Ca2+]i increase, indicating the specificity of the Ca2+ response to Epo stimulation. In this study, the erythropoietin-regulated calcium channel was identified by single channel recordings. Use of conventional whole cell patch-clamp failed to detect Epo-induced whole cell Ca2+ current. To minimize washout of cytosolic constituents, we next used nystatin perforated patch, but did not find any Epo-induced whole cell Ca2+ current. Using Ba2+ (30 mmol/L) as charge carrier in cell-attached patches, we detected single channels with unitary conductance of 3.2 pS, reversal potential of +72 mV, and whose unitary current (at +10 mV) increased monotonically with increasing Ba2+ concentrations. Channel open probability did not appreciably change over the voltage range (−50 to +30 mV) tested. Epo (2 U/mL) increased both mean open time (from 4.27 ± 0.75 to 11.15 ± 1.80 ms) and open probability (from 0.26 ± 0.06 to 2.56 ± 0.59%) of this Ba2+-permeable channel. Our data strongly support the conclusion that the Epo-induced [Ca2+]i increase in human erythroblasts is mediated via Ca2+ entry through a voltage-independent Ca2+ channel.
Macrophage Inflammatory Protein-1α and Interferon-Inducible Protein 10 Inhibit Synergistically Induced Growth Factor Stimulation of MAP Kinase Activity and Suppress Phosphorylation of Eukaryotic Initiation Factor 4E and 4E Binding Protein 1
Authors: Aronica Susan M. , Gingras Anne-Claude , Sonenberg Nahum , Cooper Scott , Hague Nancy , Broxmeyer Hal E. 
Published: October 2019

AbstractGranulocyte-macrophage colony-stimulating factor (GM-CSF ) and Steel factor (SLF ) synergistically stimulate Raf-1 kinase activity, protein synthesis, and proliferation in hematopoietic MO7e cells; synergistic action of these factors is blocked by the suppressive chemokines macrophage inflammatory protein-1α (MIP-1α) and interferon-inducible protein 10 (IP-10; Aronica et al, J Biol Chem 270:21998, 1995). We assessed the potential for both stimulatory and inhibitory factors to act through the MAP kinase signaling pathway by studying the effects of growth factors and chemokines on MAP kinase activation. Also, because activation of kinase signaling pathways and stimulation of protein synthesis by peptide growth factors are associated with increased phosphorylation of eukaryotic initiation factor 4E (eIF-4E) and the translational repressor 4E-binding protein 1 (4E-BP1) in some target cells, we investigated whether growth factor treatment could alter eIF-4E or 4E-BP1 phosphorylation state in MO7e cells. We report that treatment of MO7e cells with GM-CSF and SLF stimulated significant, greater-than-additive increases in MAP kinase activity and the phosphorylation of both eIF-4E and 4E-BP1. Increased 4E-BP1 phosphorylation correlated with a decrease in the association of 4E-BP1 with eIF-4E. Growth factor-induced phosphorylation of 4E-BP1 and dissociation of 4E-BP1 from eIF-4E was blocked in cells treated with rapamycin, wortmannin, or PD098059. Treatment of cells with IP-10 or MIP-1α blocked the stimulatory effects of GM-CSF and SLF, resulting in suppression of MAP kinase activity, eIF-4E and 4E-BP1 phosphorylation, and eIF-4E/4E-BP1 dissociation. Our results suggest that GM-CSF and SLF exert part of their combined growth-promoting effects on MO7e cells through activation of MAP kinase and enhancement of eIF-4E and 4E-BP1 phosphorylation and dissociation and that suppression of growth factor-induced protein synthesis by MIP-1α and IP-10 involves translational repression at the level of eIF-4E.
Involvement of Retinoic Acid Receptor-α–Mediated Signaling Pathway in Induction of CD38 Cell-Surface Antigen
Authors: Mehta Kapil , McQueen Teresa , Manshouri Taghi , Andreeff Michael , Collins Steven , Albitar Maher 
Published: October 2019

AbstractHuman leukocyte antigen CD38, a 45-kD single-chain, transmembrane glycoprotein, is a bifunctional ectoenzyme that participates in signal transduction pathways involved in the regulation of cell growth and differentiation. In this study, we demonstrate the nature of retinoid receptors involved in retinoic acid–induced expression of CD38 protein in the human myeloblastic leukemia cell line HL-60. We used a variant HL-60 cell line, HL-60R, in which retinoid receptor function has been abrogated by a trans-dominant negative mutation. We introduced the normal retinoic acid receptors (RAR)-α, -β, and -γ or retinoid X receptor (RXR)-α into HL-60R cells by retroviral vector-mediated gene transfer. Based on experiments using these cell lines and receptor-specific synthetic retinoids that preferentially bind to one of the RARs or RXRs, we conclude that RAR-α is involved in retinoid-induced CD38 expression in HL-60 cells. Further evidence included our demonstration that blocking of RAR-α with the antagonist Ro 41-5253 completely suppressed the retinoid-induced expression of CD38 mRNA transcript and the production of CD38 protein in HL-60 cells. Various tissues from transgenic mice that expressed an antisense construct of RAR-α lacked or produced very low levels of CD38. As expected, the tissues from transgenic mice contained 50% to 80% reduced levels of RAR-α. These results suggest that regulation of CD38 expression, both in vitro and in vivo, is under the direct control of RAR-α retinoid receptors.
Transcription Factor GATA-2 Is Required for Proliferation/Survival of Early Hematopoietic Cells and Mast Cell Formation, But Not for Erythroid and Myeloid Terminal Differentiation
Authors: Tsai Fong-Ying , Orkin Stuart H. 
Published: October 2019

AbstractThe zinc-finger transcription factor GATA-2 plays a critical role in maintaining the pool of early hematopoietic cells. To define its specific functions in the proliferation, survival, and differentiation of hematopoietic cells, we analyzed the hematopoietic potential of GATA-2−/− cells in in vitro culture systems for proliferation and maintenance of uncommitted progenitors or differentiation of specific lineages. From a two-step in vitro differentiation assay of embryonic stem cells and in vitro culture of yolk sac cells, we demonstrate that GATA-2 is required for the expansion of multipotential hematopoietic progenitors and the formation of mast cells, but dispensable for the terminal differentiation of erythroid cells and macrophages. The rare GATA-2−/− multipotential progenitors that survive proliferate poorly and generate small colonies with extensive cell death, implying that GATA-2 may play a role in both the proliferation and survival of early hematopoietic cells. To explore possible mechanisms resulting in the hematopoietic defects of GATA-2−/− cells, we interbred mutant mouse strains to assess the effects of p53 loss on the behavior of GATA-2−/− hematopoietic cells. Analysis of GATA-2−/−/p53−/− compound-mutant embryos shows that the absence of p53 partially restores the number of total GATA-2−/− hematopoietic cells, and therefore suggests a potential link between GATA-2 and p53 pathways.
Isolation of Human Blood Dendritic Cells Using the CMRF-44 Monoclonal Antibody: Implications for Studies on Antigen-Presenting Cell Function and Immunotherapy
Authors: Fearnley D.B. , McLellan A.D. , Mannering S.I. , Hock B.D. , Hart D.N.J. 
Published: October 2019

AbstractDendritic cells (DC) are potent antigen-presenting cells (APC) with the capacity to stimulate a primary T lymphocyte immune response and are therefore of interest for potential immunotherapeutic applications. Freshly isolated DC or DC precursors may be preferable for studies of antigen uptake and the potential control of APC costimulator activity. In this report, we report that the monoclonal antibody CMRF-44 can be used to detect early DC differentiation. The majority of DC circulating in blood do not express any known DC lineage specific markers, but can be identified by CMRF-44 labeling after a brief period of in vitro culture. The sequential acquisition of DC activation antigens allows the identification of two stages of DC maturation/activation. Cytokines, especially granulocyte-macrophage colony-stimulating factor (GM-CSF ) and tumor necrosis factor (TNF )α, enhance both phases of this process, whereas CD40-ligand trimer preferentially enhances the final DC maturation to a fully mature, activated phenotype. DC positively selected using CMRF-44 possess potent allostimulatory activity and are efficient at the uptake, processing, and presentation of soluble antigens for both primary and secondary immune responses. CMRF-44+ DC are also more potent than other APC types at restimulation of a chronic myeloid leukemia peptide specific T-cell clone. The use of a purified population of freshly isolated DC may be advantageous in attempts to initiate, maintain, and direct immune responses for immunotherapeutic applications.
Immunolocalization of the ICE/Ced-3–Family Protease, CPP32 (Caspase-3), in Non-Hodgkin's Lymphomas, Chronic Lymphocytic Leukemias, and Reactive Lymph Nodes
Authors: Krajewski Stanislaw , Gascoyne Randy D. , Zapata Juan M. , Krajewska Maryla , Kitada Shinichi , Chhanabhai Mukesh , Horsman Douglas , Berean Ken , Piro Lawrence D. , Fugier-Vivier Isabelle , Liu Yong-Jun , Wang Hong-Gang , Reed John C. 
Published: October 2019

AbstractImmunohistochemical analysis of the apoptosis-effector protease CPP32 (Caspase-3) in normal lymph nodes, tonsils, and nodes affected with reactive hyperplasia (n = 22) showed strong immunoreactivity in the apoptosis-prone germinal center B-lymphocytes of secondary follicles, but little or no reactivity in the surrounding long-lived mantle zone lymphocytes. Immunoblot analysis of fluorescence-activated cell sorted germinal center and mantle zone B cells supported the immunohistochemical results. In 22 of 27 (81%) follicular small cleaved cell non-Hodgkin's B-cell lymphomas, the CPP32-immunopositive germinal center lymphocytes were replaced by CPP32-negative tumor cells. In contrast, the large cell component of follicular mixed cells (FMs) and follicular large cell lymphomas (FLCLs) was strongly CPP32 immunopositive in 12 of 17 (71%) and in 8 of 14 (57%) cases, respectively, whereas the residual small-cleaved cells were poorly stained for CPP32 in all FLCLs and in 12 of 17 (71%) FMs, suggesting that an upregulation of CPP32 immunoreactivity occurred during progression. Similarly, cytosolic immunostaining for CPP32 was present in 10 of 12 (83%) diffuse large cell lymphomas (DLCLs) and 2 of 3 diffuse mixed B-cell lymphomas (DMs). Immunopositivity for CPP32 was also found in the majority of other types of non-Hodgkin's lymphomas studied. Plasmacytomas were CPP32 immunonegative in 4 of 12 (33%) cases, in contrast to normal plasma cells, which uniformly contained intense CPP32 immunoreactivity, implying downregulation of CPP32 in a subset of these malignancies. All 12 peripheral blood B-cell chronic lymphocyte leukemia specimens examined were CPP32 immunopositive, whereas 3 of 3 small lymphocytic lymphomas were CPP32 negative, suggesting that CPP32 expression may vary depending on the tissue compartment in which these neoplastic B cells reside. The results show dynamic regulation of CPP32 expression in normal and malignant lymphocytes.
Lack of Fc-ε Receptors on Murine Eosinophils: Implications for the Functional Significance of Elevated IgE and Eosinophils in Parasitic Infections
Authors: de Andres Belen , Rakasz Eva , Hagen Michael , McCormik Mike L. , Mueller Allen L. , Elliot David , Metwali Ahmed , Sandor Matyas , Britigan Bradley E. , Weinstock Joel V. , Lynch Richard G. 
Published: October 2019

AbstractChronic infection with Schistosoma mansoni induces in humans and mice a Th2-dominant immune response in which eosinophils and IgE are conspicuously elevated. Human eosinophils express IgE receptors that participate in an IgE-dependent eosinophil-mediated ADCC reaction against Schistosomula larvae in vitro. To investigate the expression of IgE receptors on murine eosinophils, they were purified (<95% pure by Giemsa-stained cytospin preparations) from liver granulomas of Schistosoma-infected mice. Flow cytometric analysis showed the absence of the low-affinity IgE receptor Fc-ε RII (CD23) and Mac-2 and the absence of binding of murine IgE. Reverse transcription-polymerase chain reaction (RT-PCR) analysis of granuloma eosinophil mRNA did not detect transcripts for Fc-ε RII or the α-chain of the high-affinity IgE receptor Fc-ε RI, but did detect transcripts that encode Mac-2 and the low-affinity IgG receptors Fc-γ RIIb2, Fc-γ RIII, and the FcR-associated γ-chain. In vitro stimulation of granuloma eosinophils with interleukin-4 (IL-4) did not induce IgE binding, surface expression of Mac-2, or the transcription of Fc-ε receptors (Fc-ε RI, Fc-ε RII/CD23). To investigate normal murine eosinophils, we cultured normal mouse bone marrow cells with recombinant IL-3, recombinant IL-5, and recombinant granulocyte-macrophage colony-stimulating factor, conditions that promote eosinophil differentiation. Flow cytometric analysis of bone marrow-derived eosinophils failed to detect IgE binding or cell surface expression of Fc-ε RII and Mac-2, and RT-PCR analysis of fluorescence-activated cell sorted bone marrow-derived eosinophils failed to detect transcripts that encode Fc-ε RI or Fc-ε RII. These findings show that, in contrast to human eosinophils, murine eosinophils do not express cell surface receptors that bind IgE. However, because IgG receptors (Fc-γ RIIb2, Fc-γ RIII) were present on eosinophils purified from granulomas, we investigated whether they might be involved in eosinophil activation. We found that an oxidative burst in eosinophils could be triggered through their IgG receptors.
Successful Correction of Hemophagocytic Lymphohistiocytosis With Related or Unrelated Bone Marrow Transplantation
Authors: Baker K. Scott , DeLaat Cynthia A. , Steinbuch Michael , Gross Thomas G. , Shapiro Ralph S. , Loechelt Brett , Harris Richard , Filipovich Alexandra H. 
Published: October 2019

AbstractHemophagocytic lymphohistiocytosis (HLH) is a life-threatening disorder of immune regulation leading to widespread lymphocytic and hemophagocytic infiltration of vital organs. Apparent cure has only been achieved with allogeneic bone marrow transplantation (BMT). This report describes 20 consecutive patients, who underwent either matched sibling donor (n = 4) or unrelated donor (URD; n = 16) BMT. Age at the time of BMT was 0.4 to 5.3 years (median, 0.8 years). Central nervous system disease was present at diagnosis in 13 patients. At BMT, 14 patients were in a clinical remission, whereas 6 patients had active HLH. All patients were engrafted after cytoreduction with busulfan, cyclophosphamide, and etoposide. The probability of grade II-III acute graft-versus-host disease (GVHD) for all patients was 57% (95% confidence limit [CL], 0.28, 0.86), and 73% (95% CL, 0.44, 1.0) in URD patients. The overall probability of survival at 3 years was 45% (95% CL, 0.23, 0.67) and 44% (95% CL, 0.19, 0.68) when URD BMT was evaluated separately. Favorable BMT outcome was associated with clinical remission status at the time of BMT. The preparative regimen was well tolerated, and in the 9 surviving patients it provided durable engraftment and was effective at eradicating the underlying disease.
Cytomegalovirus-Specific T-Cell Immunity in Recipients of Autologous Peripheral Blood Stem Cell or Bone Marrow Transplants
Authors: Reusser Pierre , Attenhofer Rudolf , Hebart Holger , Helg Claudine , Chapuis Bernard , Einsele Herrmann 
Published: October 2019

AbstractThe cytomegalovirus (CMV)-specific CD8+ cytotoxic T-lymphocyte (CTL) and CD4+ T-helper cell (Th) functions were characterized in 15 CMV seropositive recipients of autologous peripheral blood stem cell or bone marrow transplants. These immune functions were evaluated in peripheral blood specimens obtained before and at 1, 2, and 3 months after transplant. For study of CTL activity, blood mononuclear cells were cocultured with CMV-infected autologous fibroblasts for 2 weeks and then tested for cytotoxicity against CMV-infected or mock-infected autologous and HLA-mismatched fibroblasts. The Th response to CMV antigen was assessed by standard lymphoproliferative assay. CMV-specific CD8+ CTL and CD4+ Th responses were detectable in 12 (80%) and 14 (93%) patients, respectively, in the first 3 months after transplantation. A Th response to CMV was always present by the time of first CTL detection. During the posttransplant period, CMV infection occurred in 6 (40%) patients, and detection of CMV-specific CD8+ CTL activity was associated with protection from subsequent CMV infection (P = .002). Among CMV seropositive autograft recipients, CMV-specific CD8+ CTL and CD4+ Th responses are restored in a large proportion of patients in the first 3 months after transplantation, and the presence of a specific CD8+ CTL activity affords protection from CMV infection.
Activation of Human Plasminogen by Staphylokinase. Direct Evidence That Preformed Plasmin Is Necessary for Activation to Occur
Authors: Grella Davida K. , Castellino Francis J. 
Published: October 2019

AbstractTo directly determine whether the mechanism of activation of human plasminogen (HPg) by staphylokinase (Sak) required formation of an active complex of Sak and HPg, recombinant (r) variants of HPg were examined that allowed dissection of the steps involved in this activation. The rate of activation of wild-type (wt) r-HPg by equimolar levels of Sak was enhanced when small amounts of human plasmin (HPm) were included, suggesting that a Sak-HPm complex was a more effective plasminogen activator than a putative Sak-HPg complex. Incubation of equimolar Sak with a cleavage site resistant mutant of HPg (r-[R561 A]HPg) did not result in generation of amidolytic activity of the complex, in contrast to a similar experiment with streptokinase (SK) in place of Sak, where substantial amidolytic activity was generated. This result supplies evidence that an active complex of Sak and HPg does not form, as is the case with SK. Another mutant, r-[D646E]HPg, which, upon activation, would lead to a form of HPm defective in enzymatic activity, is also not converted to its two-chain form by Sak, but is converted to the inactive two-chain form by urokinase, a direct plasminogen activator, and by equimolar complexes of SK or Sak with wtr-HPm. This shows that the active site of HPm is the functional plasminogen activator entity in the Sak-HPm complex. These results show that the mechanism of activation of HPg by Sak proceeds in a distinctly different manner than the similar activation by SK. Although SK does not require the presence of HPm for this activation, a necessary condition for the activation by Sak is formation of a small amount of HPm generated via another activation pathway. These different mechanisms have significant implications in production of the fibrinolytic state by these two indirect bacterial plasminogen activators.