bluuebunny/crossref_metadata_2025 huggingface dataset:
Adhesion and homing of blood-borne cells in bone marrow microvessels
Authors: Mazo Irina B , von Andrian Ulrich H
Published: January 2018

After birth, the bone marrow (BM) is the principal site of hematopoiesis in mammals. Thus, a large number of newly formed blood cells must penetrate the wall of BM microvessels to enter the circulation. In addition, the BM appears to function as a lymphoid organ and is also part of the macrophagal system. Subsets of circulating lymphocytes and other cells of the immune system continuously home to the BM. However, neither the mechanisms of blood cell migration to and from the BM nor its precise role in the immune system are well understood. One reason for the relative paucity of data on BM physiology is the fact that normal BM is surrounded by thick cortical bone that impedes direct observation and experimental manipulation. One notable exception is the calvaria of the murine skull where hematopoietically active BM is only covered by a thin lamella of bone that is sufficiently translucent to allow a detailed in situ analysis of the BM microcirculation by epi-fluorescence microscopy. Here, we review our current knowledge of the anatomic, hemodynamic, and endothelial properties of the specialized microvascular bed within murine skull BM. In addition, we summarize recent studies on the molecular mechanisms that mediate the homing of circulating hematopoietic progenitor cells to the BM, an event that is critical for the success of BM transplantations. J. Leukoc. Biol. 66: 25–32; 1999.
Involvement of caveolae in the uptake of respiratory syncytial virus antigen by dendritic cells
Authors: Werling Dirk , Hope Jayne C , Chaplin Paul , Collins Robert A , Taylor Geraldine , Howard Chris J
Published: January 2018

The uptake of respiratory syncytial virus (RSV) antigen by cattle dendritic cells was investigated. Pathways of antigen uptake were monitored by flow cytometry using specific tracers and by proliferation assays, which were used to measure the presentation of RSV antigen and ovalbumin. Inhibitors that differentially affected pathways were used to distinguish them. Presentation of RSV antigen, but not ovalbumin, was inhibited by phorbol myristate acetate and filipin, which have been reported to inhibit caveolae, but not by cytochalasin D, amiloride, or mannose. These inhibitors have been reported to block macropinocytosis and other actin-dependent uptake mechanisms, endocytic pathways involving clathrin-coated pits, and the mannose receptor. Furthermore, co-localization of RSV antigen and caveolae was observed by confocal microscopy. Thus, the major route for uptake of RSV antigen by cattle dendritic cells is one mediated by caveolae, adding a pathway of antigen uptake by dendritic cells to those established. J. Leukoc. Biol. 66: 50–58; 1999.
Respiratory syncytial virus infection of human respiratory epithelial cells enhances inducible nitric oxide synthase gene expression
Authors: Tsutsumi Hiroyuki , Takeuchi Ryoh , Ohsaki Masaya , Seki Kimihira , Chiba Shunzo
Published: January 2018

The induction kinetics of the mRNA of interferon regulatory factor 1 (IRF-1), inducible nitric oxide synthase (iNOS), and proinflammatory cytokines in respiratory syncytial virus (RSV)-infected human type 2 alveolar epithelial cells (A549 cells) were analyzed semiquantitatively by RT-PCR. RSV enhanced IRF-1 and iNOS mRNA expression as early as 4 h after RSV infection and this enhancement lasted several hours. No IFN-γ gene expression was observed during the whole course of the infection. Expression of IFN-β, IL-1β, and TNF-α genes was observed slightly at 4 h and became marked 7 h after infection. Addition of neutralizing antibodies to these cytokines to the culture had no effect on the induction of iNOS mRNA. The iNOS transcriptional activity in RSV-infected cells was significantly enhanced by an exogenous cytokine mixture (IL-1β, TNF-α, and IFN-γ). An apparent nitric oxide (NO) production was identified only when cytokines were added together with RSV infection. A significant increase of iNOS gene expression was observed in nasopharyngeal exudate cells obtained from infants during the acute phase of RSV bronchiolitis. These observations suggest that RSV infection of human respiratory epithelial cells induces the iNOS gene both in vitro and in vivo; this induction may occur rather promptly and involves transcriptional activator IRF-1 induced by the RSV infection itself. The iNOS gene, which is initially induced by RSV infection, may be further enhanced in a paracrine fashion by proinflammatory cytokines released by infection-activated inflammatory cells. J. Leukoc. Biol. 66: 99–104; 1999.
Positive and negative regulation of the myeloid dendritic cell lineage
Authors: Santiago-Schwarz Frances
Published: January 2018

Recent advances have revealed that dendritic cells (DCs) are not a single cell type, but a system of cells that are phenotypically and functionally diverse. DC subtypes stemming from the myeloid and lymphoid lineages promote a diversity of immune responses ranging from the stimulation of naive T and B cell responses to the down-regulation of T cell responses. Although differences in antigen handling are linked to DC developmental stages in the myeloid DC lineage, the particular type of immune response elicited may be determined by a specific DC subtype. This review summarizes key regulatory mechanisms controlling the development of myeloid lineage DCs from multipotent progenitors. Emphasis is placed on describing a highly orchestrated series of proliferative, apoptotic, and developmental events involving granulocyte-macrophage colony-stimulating factor, transforming growth factor β, and the tumor necrosis factor α, CD95, and bcl-2 protein families. J. Leukoc. Biol. 66: 209–216; 1999.
Myb-transformed hematopoietic cells as a model for monocyte differentiation into dendritic cells and macrophages
Authors: Banyer Joanne L , Hapel Andrew J
Published: January 2018

Immune induction is effected through the interaction of antigen-presenting cells with specific receptors on the surface of thymus-derived lymphocytes. Cells most able to ingest, process, and present antigen appear to be related to the mononuclear phagocyte/neutrophil series. For example dendritic cells (DC) can be found in colonies of GM-CSF-responsive bone marrow cells, and under experimental conditions are routinely expanded as a population in vitro from GM-CSF-responsive progenitor cells. To address the question of DC lineage and to determine what genes are involved in lineage commitment, we have generated a series of GM-CSF-responsive cell lines that can be induced to differentiate in a homogeneous manner in vitro. The cloned cell lines are derived from 12-day fetal liver and are transformed with a truncated form of c-myb, which lacks the normal autoregulatory sequences. As far as we know, these myb-transformed hemopoietic cells (MTHC) differ from normal only in the unregulated expression of myb, a gene whose expression is obligatory for proliferation of hemopoietic cells. MTHC in the presence of TNF-α and IL-4 will differentiate into cells that have many of the properties of macrophages. When the same MTHC lines are exposed to TNF-α in combination with IFN-γ, the cells instead become DC. The differentiated DC are potent presenters of antigen in mixed lymphocyte reactions and of soluble antigen to specific T cell lines. Thus, cells with the properties of both macrophages and DC can be derived from a single type of GM-CSF-responsive progenitor cell. We have used this MTHC system to analyze differences in gene expression as the cells mature along the DC and macrophage pathways. A distinctive pattern of differentially expressed cDNAs is evident where macrophage-specific cDNAs are homologous to genes encoding cytoskeletal and cell-surface proteins, whereas the DC-specific cDNAs are homologous to signaling, chemokine, and IFN-γ-inducible genes. We discuss the utility of MTHC in analyzing the relationships between DC and macrophages, and suggest that DC and macrophages represent extreme phenotypes in a spectrum of antigen handling cells that are somewhat interchangeable, depending on their immediate environment. J. Leukoc. Biol. 66: 217–223; 1999.
Regulation of dendritic cell trafficking: a process that involves the participation of selective chemokines
Authors: Dieu-Nosjean Marie-Caroline , Vicari Alain , Lebecque Serge , Caux Christophe
Published: January 2018

DC function as sentinels of the immune system. They traffic from the blood to the tissues where, while immature, they capture antigens. They then leave the tissues and move to the draining lymphoid organs where, converted into mature DC, they prime naive T cells. This suggestive link between DC traffic pattern and functions led to the investigation of the chemokine responsiveness of DC during their development and maturation. These studies have shown that immature and mature DC are not recruited by the same chemokines. Immature DC respond to many CC- and CXC-chemokines (MIP-1α, MIP-1β, MIP-5, MCP-3, MCP-4, RANTES, TECK, and SDF-1) and in particular to MIP-3α/LARC, which acts through CCR6, a receptor mainly expressed in DC and lymphocytes. Like most other chemokines acting on immature DC, MIP-3α is inducible on inflammatory stimuli. In contrast, mature DC have lost their responsiveness to most of these chemokines through receptor down-regulation or desensitization, but acquired responsiveness to MIP-3β/ELC and 6Ckine/SLC as a consequence of CCR7 up-regulation. MIP-3α mRNA is only detected within inflamed epithelial crypts of tonsils, the site of antigen entry known to be infiltrated by immature DC, whereas MIP-3β and 6Ckine are specifically expressed in the T cell-rich areas where mature IDC home. These observations suggest a role for chemokines induced on inflammation such as MIP-3α in recruitment of immature DC at the site of injury and a role for MIP-3β/6Ckine in accumulation of antigen-loaded mature DC in T cell-rich areas of the draining lymph node. A better understanding of the regulation of DC trafficking might offer new opportunities of therapeutic interventions to suppress or stimulate the immune response. J. Leukoc. Biol. 66: 252–262; 1999.
Retroviral gene transfer, rapid selection, and maintenance of the immature phenotype in mouse dendritic cells
Authors: Gasperi C , Rescigno M , Granucci F , Citterio S , Matyszak M K , Sciurpi M T , Lanfrancone L , Ricciardi-Castagnoli P
Published: January 2018

We used the retroviral vector PINCO [which expresses the green fluorescent protein (GFP) as a selectable marker], to infect growth factor-dependent immature D1 dendritic cells (DC). The efficiency of infection in different experiments was between 5 and 30%, but subsequent cell sorting led to a virtually homogeneous population of GFP-positive cells. Retroviral infection did not modify the immature DC phenotype, as shown by the low expression of major histocompatibility complex and co-stimulatory molecules. Furthermore, the GFP-positive D1 cells underwent full maturation after lipopolysaccharide treatment, as indicated by a high expression of cell-surface MHC and co-stimulatory molecules, and also by strong stimulatory activity in allogeneic mixed lymphocyte reaction. The high efficiency of this retroviral system, the rapidity of the technique, and the possibility to overcome in vitro selection make this method very attractive for the stable introduction of heterologous genes into proliferating immature mouse D1 cells. Furthermore, this approach is suitable for functional studies of new DC-specific genes involved in DC maturation and survival. J. Leukoc. Biol. 66: 263–267; 1999.
Dendritic cells and the pathogenesis of rheumatoid arthritis
Authors: Thomas Ranjeny , MacDonald Kelli PA , Pettit Allison R , Cavanagh Lois L , Padmanabha Jagdish , Zehntner Simone
Published: January 2018

Rheumatoid arthritis (RA) is a chronic autoimmune inflammatory disease in which unknown arthrogenic autoantigen is presented to CD4+ T cells. The strong association of the disease with an epitope within the HLA-DR chain shared between various alleles of HLA-DR4 and DR1 emphasizes the importance of antigen presentation. This immune response predominantly occurs in the synovial tissue and fluid of the joints and autoreactive T cells are readily demonstrable in both the synovial compartment and blood. Circulating dendritic cells (DC) are phenotypically and functionally identical with normal peripheral blood (PB) DC. In the synovial tissue, fully differentiated perivascular DC are found in close association with T cells and with B cell follicles, sometimes containing follicular DC. These perivascular DC migrate across the activated endothelium from blood and receive differentiative signals within the joint from monocyte-derived cytokines and CD40-ligand+ T cells. In the SF, DC manifest an intermediate phenotype, similar to that of monocyte-derived DC in vitro. Like a delayed-type hypersensitivity response, the rheumatoid synovium represents an effector site. DC at many effector sites have a characteristic pattern of infiltration and differentiation. It is important to note that the effector response is not self-limiting in RA autoimmune inflammation. In this article, we argue that the presentation of self-antigen by DC and by autoantibody-producing B cells is critical for the perpetuation of the autoimmune response. Permanently arresting this ongoing immune response with either pharmaceutical agents or immunotherapy is a major challenge for immunology. J. Leukoc. Biol. 66: 286–292; 1999.
Peripheral blood allogeneic microchimerism in lung and cardiac allograft recipients
Authors: Reinsmoen Nancy L , Jackson Annette , Hertz Marshall , Savik Kay , Kubo Spencer , Ormaza Sophia , Miller Leslie , McSherry Cynthia
Published: January 2018

We have been investigating two parameters, donor antigen-specific hyporeactivity and peripheral blood allogeneic microchimerism, to determine whether these parameters will predict a chronic rejection-free state and which recipients may be candidates for steroid withdrawal. We have identified donor antigen-specific hyporeactivity for 33% (16/48) of lung and 23% (11/47) of heart recipients. For both organ groups, the hyporeactive subgroup experienced a lower incidence of chronic rejection. The probability of donor antigen-specific hyporeactivity predicting a chronic rejection-free state is 100% for lung and 91% for heart recipients. We have identified peripheral blood allogeneic microchimerism for 77% (20/26) of lung and 36% (9/25) of heart recipients tested at 12–18 months posttransplant. Donor antigen-specific hyporeactivity correlates with a critical level of donor cells in lung recipients; the probability of high peripheral blood allogeneic microchimerism levels predicting a chronic rejection-free state in lung recipients is 100%. The results in heart recipients are not as clear with a short-, but not long-term, trend of higher chimerism levels correlating with the development of donor antigen-specific hyporeactivity. These results illustrate the usefulness of immune parameters to predict long-term graft outcome in an organ-specific manner. J. Leukoc. Biol. 66: 306–309; 1999.
Delayed clearance of apoptotic lymphoma cells allows cross-presentation of intracellular antigens by mature dendritic cells
Authors: Rovere Patrizia , Sabbadini Maria Grazia , Vallinoto Cristina , Fascio Umberto , Zimmermann Valerie S , Bondanza Attilio , Ricciardi-Castagnoli Paola , Manfredi Angelo A
Published: January 2018

Single cells are deleted from the midst of living tissue during normal turnover and embryogenesis. This event is not associated with inflammation or autoimmunity. Little is known of the clearance of apoptotic cells during dangerous situations, accompanied by extensive cell death and tissue damage: when macrophages are overwhelmed by apoptotic cells, other phagocytes, including immature dendritic cells (DCs), may become involved. DCs efficiently present antigens derived from the processing of internalized apoptotic bodies to class I- and class II-restricted T cells. Antigen presentation results either in T cell activation or in their functional blockade. The outcome is influenced by pro-inflammatory maturative signals: efficient T cell cross-priming requires fully mature DCs. Here we discuss in vitro data suggesting that the number of apoptotic cells that die at a given time influences DC maturation and therefore their ability to uptake antigens from apoptotic cells and cross-activate T lymphocytes. J. Leukoc. Biol. 66: 345–349; 1999.
A novel family of Ig-like receptors for HLA class I molecules that modulate function of lymphoid and myeloid cells
Authors: Colonna Marco , Nakajima Hideo , Navarro Francisco , López-Botet Miguel
Published: January 2018

We review what is presently known about structure, cellular distribution, biochemical characteristics, and function of a new family of human cell-surface receptors referred to as immunoglobulin-like transcripts (ILTs), leukocyte Ig-like receptors (LIRs), or monocyte/macrophage Ig-like receptors (MIRs). These receptors are genetically, structurally, and functionally related to a group of natural killer (NK) cell receptors for HLA class I molecules known as killer cell Ig-like receptors (KIRs). Distinct ILT/LIR/MIR isotypes are differentially expressed on lymphocytes, monocytes, macrophages, dendritic cells, and granulocytes; at least some of them recognize HLA class I molecules. Whereas some isotypes either inhibit or induce cell activation, others may be secreted as soluble receptors. ILT/LIR/MIR receptors may allow all immune cells to monitor class I expression on other cells and to respond in its absence, just as NK cells do. In addition, they may contribute to homeostasis by establishing activation thresholds that can be overcome only by relevant triggering stimuli and not by bystander cells. J. Leukoc. Biol. 66: 375–381; 1999.
Synovial PMN show a coordinated up-regulation of CD66 molecules
Authors: Hönig M , Peter H H , Jantscheff P , Grunert F
Published: January 2018

Changes in the expression of various activation-dependent surface markers have been reported for polymorphonuclear neutrophils (PMN) isolated from synovial fluid of patients with inflammatory joint diseases. We extend these findings to the expression of CD66 molecules and several other surface markers. Three members of the CD66 family, namely CD66a, CD66b, and CD66c, showed an up to fourfold up-regulation on synovial fluid PMN compared with peripheral blood PMN (PBG) of the same patients; CD59 was increased twofold, the expression of CD16 did not change, whereas CD62L was reduced by more than 50% on synovial fluid PMN. It is interesting that CD66a, CD66b, and CD66c showed a coordinated expression on PBG of patients and controls and a coordinated up-regulation on synovial neutrophils. In contrast, after in vitro stimulation of peripheral blood PMN with phorbol myristate acetate, CD66c was much less up-regulated compared with CD66a and CD66b. All samples of synovial fluid PMN exhibited an additional increase in the expression of CD66a, CD66b, and CD66c when stimulated with phorbol myristate acetate in vitro. Prostaglandins are known to inhibit various responses of neutrophils to inflammatory stimuli. We could show that prostaglandins inhibit N-formyl-methionyl-leucyl-phenylalanine-induced up-regulation of CD66 on peripheral blood PMN in a concentration-dependent manner. J. Leukoc. Biol. 66: 429–436; 1999.
Functional coupling and differential regulation of the Phospholipase A2-cyclooxygenase pathways in inflammation
Authors: Scott Kieran F , Bryant Katherine J , Bidgood Matthew J
Published: January 2018

Prostaglandins generated by the phospholipase A2 (PLA2)/cyclooxygenase (COX) pathway are well known to mediate diverse intracellular and extracellular effects that regulate mammalian development, vascular function, renal physiology, parturition, and immune responses to infection or wounding. In immune-mediated diseases and in certain cancers, this pathway is aberrantly upregulated and excessive prostaglandin production contributes to the pathology. It is now known that there are two isoforms of COX and multiple secreted and intracellular PLA2 enzymes. The use of isoform-specific inhibitors, coupled with antisense and in vivo gene deletion experiments, has identified independent pathways of arachidonic acid metabolism, which are differentially regulated at the levels of gene expression, protein phosphorylation, and cellular localization. There is cross-talk between the pathways at the level of PLA2 and substrate supply to the two isoforms of COX is apparently compartmentalized. Knockout studies have shown that the two COX isoforms play independent roles in immediate and delayed agonist- induced prostaglandin synthesis. Cytosolic PLA2-α is essential for both responses. Inducible secreted forms of PLA2 are, as yet, not essential for either response with the exception of the in vitro murine mast cell immediate response and instances of murine macrophage prostaglandin synthesis. These enzymes amplify the delayed response and are likely to modulate the severity of immune-mediated diseases. J. Leukoc. Biol. 66: 535–541; 1999.
Expression of serum amyloid A3 mRNA by inflammatory macrophages exposed to membrane glycoconjugates from Trypanosoma cruzi
Authors: Ferreira Ludmila R P , Silva Aristóbolo M , Michailowsky Vladimir , Reis Luiz F L , Gazzinelli Ricardo T
Published: January 2018

Differential display reverse transcriptase-polymerase chain reaction (PCR) was used to identify genes expressed by murine macrophages exposed to glycosylphosphatidylinositol-anchored mucin-like glycoproteins isolated from Trypanosoma cruzi trypomastigotes. Among the different PCR product bands identified in the differential display gel, one showed high homology with the serum amyloid A3 protein (SAA3). Northern blot assays showed augmentation of SAA3 mRNA expression by inflammatory macrophages exposed to live trypomastigotes or parasite glycolipids as compared to unstimulated macrophages. Our results also showed the expression of SAA3 mRNA, in liver and heart from animals in the acute phase of Chagas disease. It is important that expression of SAA3 mRNA was closely associated with tissue parasitism and presence of inflammatory cells. Together, our findings indicate the possible involvement of SAA3 protein on immunopathology of Chagas disease and establish a new infectious disease model to study the pathophysiological role of this acute-phase protein. J. Leukoc. Biol. 66: 593–600; 1999.
Morphine promotes apoptosis in Jurkat cells
Authors: Singhal Pravin C , Kapasi Aditi A , Reddy Krishna , Franki Nicholas , Gibbons Nora , Ding Guohua
Published: January 2018

Patients with intravenous heroin addiction are prone to recurrent infections and at times these infections are fatal. We evaluated the effect of morphine on the apoptosis of Jurkat cells and freshly isolated human T lymphocytes. Morphine promoted apoptosis of both the Jurkat cells and the freshly isolated T lymphocytes in a dose-dependent manner. DAGO, a specific p receptor agonist, also promoted Jurkat cell apoptosis. DNA isolated from morphine-treated Jurkat cells and T lymphocytes also showed integer multiples of 200 base pairs. Superoxide dismutase (SOD) enhanced lymphocyte apoptosis; whereas catalase attenuated the morphine-induced apoptosis of Jurkat cells as well as of T lymphocytes. Morphine-treated Jurkat cells also showed a decreased expression of bcl-2 and an enhanced expression of bax. In addition, morphine-treated Jurkat cells showed activation of caspase-3. These results indicate that morphine-induced T lymphocyte apoptosis may be mediated through the generation of reactive oxygen species. The change in ratio of bax and bcl-2 seems to tilt the balance toward apoptosis, leading to the activation of caspase-3. This study provides further support for the hypothesis that morphine may be directly compromising immune function by enhancing apoptosis of T lymphocytes in patients with heroin addiction. J. Leukoc. Biol. 66: 650–658; 1999.
Inhibitory and activating receptors involved in immune surveillance by human NK and myeloid cells
Authors: Colonna Marco , Nakajima Hideo , Cella Marina
Published: January 2018

We review the structure, cellular distribution, ligand specificity, and function of two emerging types of receptors involved in natural killer (NK) and myeloid cell recognition of other cells: ILT/LIR/MIR and 2B4 receptors. ILT/LIR/MIR receptors are differentially expressed on lymphoid and myeloid cells and two of them, ILT2 and ILT4, recognize HLA class I molecules. Whereas some receptors inhibit, others induce cell activation. 2B4 is broadly expressed on leukocytes, binds CD48, and mediates non-MHC-restricted cytotoxicity by NK cells. J. Leukoc. Biol. 66: 718–722; 1999.
The peroxisome proliferator-activated receptorγ (PPARγ) as a regulator of monocyte/macrophage function
Authors: Ricote Mercedes , Huang Jannet T , Welch John S , Glass Christopher K
Published: January 2018

Peroxisome proliferator-activated receptors (PPARs) are ligand-dependent transcription factors of the nuclear hormone receptor superfamily, which includes the steroid, retinoid, and thyroid hormone receptors. The PPARs can be activated by fatty acids and their eicosanoid metabolites, and have until recently been considered primarily to regulate genes involved in glucose and lipid homeostasis. In the past year there has been an explosive increase in research implicating PPARγ in macrophage biology, cell cycle regulation, and atherosclerosis. This review describes recent insights into the role of PPARγ in the macrophage lineage, and its potential function in the regulation of inflammatory responses and atherosclerosis. J. Leukoc. Biol. 66: 733–739; 1999.
Lung surfactant proteins (SP-A and SP-D) in non-adaptive host responses to infection
Authors: Holmskov Uffe
Published: January 2018

The lung surfactant proteins A and D (SP-A and SP-D) are collectins composed of C-type lectin domains attached to collagen regions. SP-A and SP-D are mainly found in the surfactant covering the pulmonary epithelial cells, but are also produced by cells lining the gastrointestinal tract. The main role of SP-A and SP-D is to interact directly with carbohydrate on the surface of microbial pathogens, thereby initiating a variety of effector mechanisms. This review focuses on the non-adaptive host responses of SP-A and SP-D to infection. Interaction of SP-A and SP-D with phagocytes is discussed and the structure and function of the putative receptors for SP-A and SP-D is presented. SP-A and SP-D seem to be regulated in a way similar to acute-phase proteins in the course of inflammation and evidence for the involvement of SP-A and SP-D as immunomodulators as well as their role in clearing allergens and modulating effector mechanisms in allergic reactions is discussed. J. Leukoc. Biol. 66: 747–752; 1999.
Heat shock response: presence and effects in burn patient neutrophils
Authors: Rodeberg David A , Meyer Joseph G , Babcock George F
Published: January 2018

Heat shock proteins (HSPs) are present in neutrophils (PMNs) from critically ill patients. We investigated whether HSPs were present in PMNs from burn patients and whether heat shock contributed to the functional defects observed in burn PMNs. Using both flow cytometry and Western blot techniques it was observed that inducible HSP72 (iHSP72) was present in PMNs and leukocytes from burn patients, especially in patients with inhalation injury. Similar to burn PMNs, and in contrast to normal cells, heat shocked PMNs (43° incubation) expressed iHSP72 and were unable to increase the expression of CD11b/CD18 in response to pro-inflammatory stimuli. Degranulation after pro-inflammatory stimuli was decreased for both burn- and heat-shocked PMNs when compared to normal controls. In burn PMNs these functional abnormalities were mainly due to decreased quantities of proteins (CD11b, albumin, B12 binding protein, β-glucuronidase) present within cytoplasmic granules. However, in heat-shocked PMNs the abnormalities were primarily related to abnormal exocytosis. In conclusion, our data show that decreased quantities of cytoplasmic granule proteins and, to a smaller degree, defective exocytosis are involved in the functional abnormalities observed in burn PMNs. J. Leukoc. Biol. 66: 773–780; 1999.
Respective involvement of TGF-β and IL-4 in the development of Langerhans cells and non-Langerhans dendritic cells from CD34+ progenitors
Authors: Caux Christophe , Massacrier Catherine , Dubois Bertrand , Valladeau Jenny , Dezutter-Dambuyant Colette , Durand Isabelle , Schmitt Daniel , Saeland Sem
Published: January 2018

In vivo, dendritic cells (DC) form a network comprising different populations. In particular, Langerhans cells (LC) appear as a unique population of cells dependent on transforming growth factor β (TGF-β) for its development. In this study, we show that endogenous TGF-β is required for the development of both LC and non-LC DC from CD34+ hematopoietic progenitor cells (HPC) through induction of DC progenitor proliferation and of CD1a+ and CD14+ DC precursor differentiation. We further demonstrate that addition of exogenous TGF-β polarized the differentiation of CD34+ HPC toward LC through induction of differentiation of CD14+ DC precursors into E-cadherin+, Lag+CD68−, and Factor XIIIa−LC, displaying typical Birbeck granules. LC generated from CD34+ HPC in the presence of exogenous TGF-β displayed overlapping functions with CD1a+ precursor-derived DC. In particular, unlike CD14+-derived DC obtained in the absence of TGF-β, they neither secreted interleukin-10 (IL-10) on CD40 triggering nor stimulated the differentiation of CD40-activated naive B cells. Finally, IL-4, when combined with granulocyte-macrophage colony-stimulating factor (GM-CSF), induced TGF-β-independent development of non-LC DC from CD34+ HPC. Similarly, the development of DC from monocytes with GM-CSF and IL-4 was TGF-β independent. Collectively these results show that TGF-β polarized CD34+ HPC differentiation toward LC, whereas IL-4 induced non-LC DC development independently of TGF-β. J. Leukoc. Biol. 66: 781–791; 1999.
Regulation of CD163 on human macrophages: cross-linking of CD163 induces signaling and activation
Authors: van den Heuvel Michel M , Tensen Cornelis P , van As Jaco H , van den Berg Timo K , Fluitsma Donna M , Dijkstra Christine D , Döpp Ed A , Droste Anne , van Gaalen Floris A , Sorg Clemens , Högger Petra , Beelen Rob H J
Published: January 2018

CD163 is a member of the group B scavenger receptor cysteine-rich (SRCR) superfamily. This study describes aspects of the tissue distribution, the regulation of expression, and signal transduction after cross-linking of this receptor at the cell surface of macrophages. CD163 showed an exclusive expression on resident macrophages (e.g., red pulp macrophages, alveolar macrophages). The expression was inducible on monocyte-derived macrophages by glucocorticoids but not by interleukin-4 (IL-4), granulocyte-macrophage colony-stimulating factor (GM-CSF), and interferon-γ. The combination of IL-4 or GM-CSF with glucocorticoids resulted in a further increase. Subcellular analysis of alveolar macrophages by immunoelectron microscopy showed a plasma membrane localization of the antigen. Cross-linking of CD163 with monoclonal antibody induced a protein tyrosine kinase-dependent signal that resulted in (1) slow-type calcium mobilization, (2) inositol triphosphate production, and (3) secretion of IL-6 and GM-CSF. The data suggest a function for the SRCR-superfamily receptor CD163 in the regulation of inflammatory processes by macrophages. J. Leukoc. Biol. 66: 858–866; 1999.
Tyrosine kinase-regulated small GTPase translocation and the activation of phospholipase D in HL60 granulocytes
Authors: Houle Martin G , Naccache Paul H , Bourgoin Sylvain
Published: January 2018

We focus on the mechanisms of regulation of phospholipase D (PLD) activity. Three agonists known to stimulate PLD activity, fMet-Leu-Phe (fMLP), phorbol 12-myristate 13-acetate (PMA) and V4+-OOH, induced a differential translocation of ADP-ribosylation factor (ARF), RhoA, and protein kinase Cα (PKCα), all cofactors for PLD activation. Whereas fMLP recruited all three proteins to membranes, V4+-OOH only elicited RhoA translocation and PMA induced ARF and PKCα translocation. Three tyrosine kinases inhibitors, ST-638, methyl 2,5-dihydroxycinnamate, and genistein reduced fMLP-stimulated PLD activity by up to 80%. Furthermore, tyrosine kinase inhibitors reduced the fMLP-induced increase of GTPγS-stimulated PLD activity in membranes and recruitment of ARF, RhoA, and PKCα to the membrane fraction. The data suggest that a tyrosine phosphorylation event is located upstream of the translocation of ARF, RhoA, and PKCα in the signaling pathway leading to PLD activation by fMLP. RO 31-8220, a specific inhibitor of PKC, reduced PMA-induced PLD activity by 80% in intact HL60 granulocytes but enhanced fMLP-stimulated PLD activity by 60%. Although PMA alone had no effect on RhoA recruitment to the membrane fraction, in the presence of RO 31-8220 the levels of membrane-bound RhoA were increased. The levels of membrane-bound ARF and PKCα were unaffected by RO 31-8220 during PMA stimulation. In contrast, fMLP-induced recruitment of ARF and RhoA was insensitive to RO 31-8220 but PKCα translocation was increased. We propose that RhoA translocation may be regulated by PKC in an ATP-independent manner. Furthermore, increased fMLP-induced PKCα translocation in the presence of RO 31-8220 may partially account for the synergistic activation of PLD observed when both fMLP and RO 31-8220 are used together in intact HL60 cells. J. Leukoc. Biol. 66: 1021–1030; 1999.
High-level expression of IkB-b in the surface epithelium of the colon: in vitro evidence for an immunomodulatory role
Authors: Wu Gary D , Huang Ning , Wen Xiaoming , Keilbaugh Sue A , Yang Hongyun
Published: January 2018

The intestinal epithelium is spatially segregated into two compartments, one containing undifferentiated cells in a proliferative state and one with non-proliferative differentiated cells. Although this epithelium can produce many immune-modulating substances, emerging evidence suggests that the differentiated cell compartment is less immune responsive. Indeed, it is the differentiated cellular compartment that represents the interface between the highly antigenic luminal environment and the mucosal immune system. The NF-κB/rel family of transcriptional activators play a critical role in regulating the inflammatory response by activating a wide variety of immune-modulating genes. These transcription factors are maintained in an inactive state in the cytoplasmic compartment by interaction with inhibitory proteins of the IκB family. In this study we show by immunohistochemistry that IκB-β is expressed at high levels specifically in the differentiated surface epithelium of the colonic mucosa. Using a naturally occurring compound found in the colon of vertebrates, butyrate, we provide evidence in an intestinal cell line that alteration of IκB-β expression can modulate the transcriptional activation of the interleukin-8 (IL-8) gene by preventing the nuclear translocation of NF-κB proteins. Therefore, the expression of IκB-β in the differentiated surface epithelium of the colon may help these cells act as an immunological barrier to prevent activation of the mucosal immune system. J. Leukoc. Biol. 66: 1049–1056; 1999.
Structural and functional evidence for microglial expression of C1qRP, the C1q receptor that enhances phagocytosis
Authors: Webster Scott D , Park Minha , Fonseca Maria I , Tenner Andrea J
Published: January 2018

Microglial activation has been associated with several degenerative diseases of the central nervous system (CNS). One consequence of activation is the induction of a more efficient phagocytic response, and it is therefore important to determine what factors regulate microglial phagocytosis and whether this capacity influences the progression of neurodegenerative changes. Previous studies have demonstrated that complement component C1q enhances Fc receptor- and CR1-mediated phagocytosis in cells of the myeloid lineage via a cell surface receptor, C1qRP. Because C1q has been found in the area of lesions in several degenerative CNS diseases, the current investigations were carried out to characterize the effects of C1q on microglial phagocytosis. Neonatal rat microglia were shown to express C1qRP as assessed by flow cytometry and immuno-cytochemistry. Interaction of these cells with substrate-bound C1q was shown to enhance both FcR-and CR1-mediated phagocytosis two- to fourfold. In addition, introduction of an antibody raised against the carboxy-terminal, cytoplasmic domain of C1qRP into microglia by electroporation markedly diminished the ability of C1q to enhance uptake of IgG-coated targets, whereas nonspecific IgG had no such effect. These results suggest that C1q in areas of active degeneration may promote the phagocytic capacity of microglia via interaction with microglial C1qRP. J. Leukoc. Biol. 67: 109–116; 2000.
Regulation of scavenger receptor CD163 expression in human monocytes and macrophages by pro- and antiinflammatory stimuli
Authors: Buechler Christa , Ritter Mirko , Orsó Evelyn , Langmann Thomas , Klucken Jochen , Schmitz Gerd
Published: January 2018

CD163, also referred to as M130, a member of the scavenger receptor cysteine-rich family (SRCR) is exclusively expressed on cells of the monocyte lineage. In freshly isolated monocytes the CD14bight CD16+ monocyte subset revealed the highest expression of CD163 among all monocyte subsets. CD163 mRNA and protein expression is up-regulated during macrophage colony-stimulating factor (M-CSF)-dependent phagocytic differentiation of human blood monocytes. In contrast, monocytic cells treated with GM-CSF and interleukin-4 (IL-4) for dendritic differentiation down-regulate this antigen. CD163 expression is also suppressed by proinflammatory mediators like lipopolysaccharide (LPS), interferon-γ (IFN-γ), and tumor necrosis factor α, whereas IL-6 and the antiinflammatory cytokine interleukin-10 (IL-10) strongly up-regulate CD163 mRNA in monocytes and macrophages. The effects of the immunosuppressants dexamethasone, cyclosporin A (CA), and cortisol differ in their capacity to influence CD163 mRNA levels. Our results demonstrate that CD163 expression in monocytes/macrophages is regulated by proinflammatory and antiinflammatory mediators. This expression pattern implies a functional role of CD163 in the antiinflammatory response of monocytes. J. Leukoc. Biol. 67: 97–103; 2000.
In vivo administration of GM-CSF promotes the clearance of apoptotic cells: effects on monocytes and polymorphonuclear leukocytes
Authors: Galati Giacomo , Rovere Patrizia , Citterio Giovanni , Bondanza Attilio , Scaglietti Ugo , Bucci Eraldo , Heltai Silvia , Fascio Umberto , Rugarli Claudio , Manfredi Angelo A
Published: January 2018

The clearance of apoptotic cells is crucial to avoid chronic inflammation and autoimmunity. Little is known about the factors that regulate it in vivo. We show that granulocyte-macrophage colony-stimulating factor (GM-CSF) administration to carcinoma patients confers to their leukocytes a significantly higher ability to phagocytose apoptotic cells than before (P < 0.005). GM-CSF increased the concentration of monocytes and polymorphonuclear leukocytes in the peripheral blood and activated circulating polymorphonuclear leukocytes. Both effects abated early after treatment, whereas phagocytosis of apoptotic cells was still significantly higher after 18 days compared with basal values (P < 0.005 and P < 0.025 for monocytes and polymorphonuclear leukocytes, respectively). On in vitro phagocytosis of apoptotic cells monocytes, but not polymorphonuclear leukocytes, up-regulated MHC class II membrane expression. These findings are consistent with the possibility that GM-CSF endows both scavenger and antigen-presenting leukocytes with the ability to internalize apoptotic tumor cells. J. Leukoc. Biol. 67: 174–182; 2000.
Regulation of ICAM-1/CD54 expression on human endothelial cells by hydrogen peroxide involves inducible NO synthase
Authors: Zadeh Majid Sadeghi , Kolb Jean-Pierre , Geromin Daniela , D'Anna Rossella , Boulmerka Amira , Marconi Anthony , Dugas Bernard , Marsac Cécile , D'Alessio Patrizia
Published: January 2018

Expression of the inducible isoform of nitric oxide synthase (iNOS) is stimulated by cytokines in human epithelial cells. This work indicates that incubation of human umbilical cord endothelial cells with combinations of interleukin-1β, tumor necrosis factor α, and interferon-γ stimulated the synthesis of iNOS mRNA, as detected by reverse transcriptase-polymerase chain reaction. It is important to note that 50, 100, and 200 μM hydrogen peroxide was able to stimulate iNOS directly. Furthermore, 100 μM H2O2 enhanced synthesis of the oxidation products, nitrite (NO) and nitrate (NO) at 12 and 36 h. iNOS protein, detected by Western blot analysis, as well as L-citrulline levels, were also increased. When endothelial cell monolayers were incubated for 1 h with 100 μM H2O2 and subsequently with cytokines, iNOS mRNA was further augmented. Under the same conditions, we regularly observed an inhibition (25%) of intercellular adhesion molecule-1 (ICAM-1/CD54) expression. The latter was reversed when the NOS inhibitor NG-monomethyl-L-arginine was added, as shown by flow cytometry. These data suggest a specific effect of endogenous hydroperoxides on the biosynthesis and processing of the human endothelial iNOS isoform. We propose that H2O2 induces a temporary NO-dependent modulation of adhesion molecule expression to limit the tissue destruction that accompanies the vascular recruitment of leukocytes. J. Leukoc. Biol. 67: 327–334; 2000.
Effects of heme proteins on nitric oxide levels and cell viability in isolated PMNs: a mechanism of toxicity
Authors: Cassidy Richard A , Burleson David G , Delgado Angel V , Kohler Dennis J , Salin Marvin L , Pruitt Basil A
Published: January 2018

Isolated human PMNs served as a model to determine oxyhemoglobin (oxyHb) binding and the effects of oxymyoglobin (oxyMb) or oxyHb on production of both nitric oxide (NO·) and superoxide (O2) and the resulting cytotoxicity. Physiologically relevant concentrations of NO and H2O2 oxidized, to a similar extent, 2,7-dichlorodihydro-fluorescein (DCFH) loaded into polymorphonuclear neutrophils (PMNs). Activation of PMNs with phorbol 12-myristate 13-acetate (PMA) markedly increased the internalization of extracellular oxyHb (10–250 μg/mL). OxyMb (10–300 μg/mL) or oxyHb (30–300 μg/mL) enhanced DCFH oxidation by a concentration-dependent mechanism in unstimulated, lipopolysaccharide (LPS) and tumor necrosis factor a (TNF-α)-, and PMA-stimulated PMNs. This increased DCFH oxidation was eliminated by NO synthase inhibitors, glutathione and ascorbate, and was reduced by albumin. Nitrite accumulation in PMN filtrates mirrored NO-induced DCF fluorescence. OxyMb-induced increases in NO levels paralleled alterations in DNA and cell membrane damage and ATP levels in PMNs and co-cultured lymphocytes, and were attenuated by NO synthase inhibitors. OxyMb eliminated extracellular O2 at protein concentrations 100- to 1000-fold above those of superoxide dismutase. These results suggest that heme proteins bind and internalize into PMNs and increase NO-induced damage in neighboring cells by inhibiting O2 -scavenging of NO We propose a mechanism whereby heme protein-induced NO levels may contribute to immunosuppression and increased infection rates associated with transfusions and cellular damage during inflammation. J. Leukoc. Biol. 67: 357–368.
Immune response to infection with Salmonella typhimurium in mice
Authors: Mittrücker Hans-Willi , Kaufmann Stefan H E
Published: January 2018

Infection of mice with Salmonella typhimurium results in systemic infection and a disease similar to that seen in humans after infection with S. typhi. The innate immune system can restrict replication of S. typhimurium to a certain degree, but for effective control and eradication of bacteria, acquired immunity is essential. Salmonella infection induces the generation of specific CD4+ and CD8+ T cells, and both T cell populations are important for protection during primary and secondary responses, although the mechanisms underlying T cell-mediated protection are not yet completely understood. Infection with S. typhimurium also results in a strong antibody response to Salmonella antigens and, in contrast to most other intracellular bacteria, this antibody response participates in protection. In summary, the response to S. typhimurium involves both T and B cell-mediated immunity, and mechanisms mediated by both lymphocyte populations are important for control of primary infection and protection against secondary infection. J. Leukoc. Biol. 67: 457–463; 2000.
A flow cytometric immune function assay for human peripheral blood dendritic cells
Authors: Willmann Kerstin , Dunne John F
Published: January 2018

CD11c+ and CD11c− (CD123+) dendritic cells (DCs) have been described in blood. Both cell types express high levels of HLA-DR and lack the lineage markers CD3, CD14, CD19, CD20, CD16, and CD56. These immunophenotypic properties were used along with analysis of activation-related surface antigens and intracellular staining of cytokines to characterize functional responses of these DC subsets to stimuli in whole human blood (WB). Samples from healthy donors were activated with lipopolysaccharide (LPS) or phorbol 12-myristate 13-acetate plus ionomycin (PMA+I). The only distinct response in CD11c−DCs was the expression of CD25 upon PMA+I activation. CD11c+ cells responded to LPS stimulation by producing high levels of interleukin-1β (IL-1β) and tumor necrosis factor α (TNF-α), and lower levels of IL-6, IL-1Ra, and IL-8 and an increased expression of accessory molecules (CD25, CD40, CD80, CD86, HLA-DR, and HLA-DQ). PMA+I activation of CD11c+ cells resulted in high levels of IL-1p and lower levels of IL-8, IL-1Ra, and TNF-ct and up-regulation of CD80, CD86, HLA-DR, and HLA-DQ. Our data support prior observations of functional differences between peripheral blood DC subsets and demonstrate the power of multiparameter flow cytometry to characterize the pleiotropic responses of these cells to various stimuli. J. Leukoc. Biol. 67: 536–544; 2000.
Lack of IL-10 synthesis by murine alveolar macrophages upon lipopolysaccharide exposure. Comparison with peritoneal macrophages
Authors: Salez Laurent , Singer Monique , Balloy Viviane , Créminon Christophe , Chignard Michel
Published: January 2018

The central role of alveolar macrophages in the establishment of lipopolysaccharide (LPS)-induced lung inflammation is well demonstrated. They produce and release numerous proinflammatory molecules, among which is tumor necrosis factor α (TNF-α), a cytokine responsible in part for the neutrophilic alveolitis. Interleu-kin-10 (IL-10) produced by LPS-activated mononuclear phagocytes is a major anti-inflammatory cytokine that down-regulates TNF-α synthesis. We studied the ability of murine alveolar macrophages to produce IL-10 in vivo and in vitro, in response to LPS. Unexpectedly, the IL-10 protein was not detected in the whole lung and airspaces after LPS intranasal instillation. In addition, no IL-10 protein was found in supernatants of isolated and LPS-stimulated alveolar macrophages. The lack of IL-10 synthesis was confirmed by the absence of specific RNA transcripts. By contrast and as expected, autologous peritoneal macrophages produced IL-10 upon LPS challenge. Drugs that usually modify the TNF-α/IL-10 balance in favor of IL-10 were used without success. Thus, maneuvers allowing an increase in intracellular cAMP concentrations did not reverse this unexpected phenotype. Moreover, direct activation of protein kinase C with PMA was unable to trigger IL-10 formation by alveolar, by contrast to peritoneal, macrophages. The current findings describe a specific phenotype for murine alveolar macrophages during LPS-induced inflammation. J. Leukoc. Biol. 67: 545–552; 2000.