bluuebunny/crossref_metadata_2025 huggingface dataset:
Relationships between phosphatidic acid and cyclic nucleotide phosphodiesterases in activated human blood mononuclear cells
Authors: Zakaroff-Girard Alexia , Bawab Samer El , Némoz Georges , Lagarde Michel , Prigent Annie-France
Published: January 2018

We have previously shown that mitogenic activation of human PBMC rapidly increases both the intracellular phosphatidic acid (PA) level and cyclic nucleotide phosphodiesterase (PDE) activity, with time-course responses, suggesting a causative relationship between the two events. PA also directly stimulated cAMP-PDE activity in acellular systems. Thus the mitogenic properties of PA might be due to its ability to lower the level of cAMP, a negative effector of lymphocyte activation, through PDE activation. In this study, human PBMC were stimulated either with the mitogenic lectin ConA, the anti-CD3 mAb OKT3, or the phorbol ester TPA. All three agonists increased the radiolabeled PA level and the PA mass in treated cells and simultaneously increased cytosolic and particulate cAMP-and cGMP-PDE activities, with significant positive correlations between PA accumulation and PDE activities. Furthermore, the ConA-induced PDE activation was dose-dependently reduced by treatment of PBMC with the diacylglycerol-kinase inhibitor R59022. This compound also dose-dependently lowered the PA level and inhibited the proliferative response to ConA. In addition, TPA-induced PDE activation was totally abolished by ethanol, which strongly reduced PA accumulation in response to the phorbol ester. These data suggest that PA increase may be linked to mitogen-induced PDE activation. Experiments performed in the presence of rolipram indicated that ConA and TPA stimulated both the rolipram-sensitive PDE4 and the rolipram-insensitive PDE activities, OKT3 being more active on PDE4. All three agonists stimulated the cGMP-specific PDE5. These results suggest that PA is an important component of the mechanisms that maintain a low level of cyclic nucleotides, which is a prerequisite for an optimal lymphoproliferative response. J. Leukoc. Biol. 65: 381–390; 1999.
Functional roles of MCP-1 in Propionibacterium acnes-induced, T cell-mediated pulmonary granulomatosis in rabbits
Authors: Ichiyasu Hidenori , Suga Moritaka , Matsukawa Akihiro , lyonaga Kazuhiro , Mizobe Takanori , Takahashi Toshihiro , Ando Masayuki
Published: January 2018

The immunological manifestation of granuloma formations in humans largely depends on the delayed-type hypersensitivity response. We investigated the involvement of monocyte chemoattractant protein-1 (MCP-1) in a rabbit model of T cell-mediated pulmonary granulomatosis. Intravenous injection of Propionibacterium acnes (P. acnes) into sensitized rabbits induced massive and diffuse pulmonary granulomas. Levels of MCP-1 in sera and bronchoalveolar lavage fluids (BALF) peaked before the granuloma formation reached the peak (on days 1 and 3 after challenge, respectively). Chemotactic activities toward monocytes and T cells in BALF were inhibited by anti-MCP-1 IgG by 80 and 36%, respectively. The phenotypic analysis of the migrating T cells revealed that activated and memory T cells rather than naive cells were preferentially attracted to the BALF. Administration of anti-MCP-1 antiserum inhibited the development of granuloma formation in both size and number, the numbers of infiltrating leukocytes in BALF, the expression of adhesion molecules on peripheral monocytes/T cells, and on macrophages/T cells in BALF, and the production of TNF-α in the lung. Anti-MCP-1 resulted in a trend toward decreased level of IL-1β in the lung. The inhibition of the production of these cytokines appeared to be induced indirectly through the inhibition of the recruitment of macrophages that produce these cytokines. The results suggest important roles of MCP-1 in the development of granuloma formation in this model through the attraction and activation of specific types of cells. J. Leukoc. Biol. 65:482–491; 1999.
To die or not to die—the quest of the TRAIL receptors
Authors: Degli-Esposti Mariapia
Published: January 2018

The last 18 months have witnessed the characterization of several new members of the tumor necrosis factor (TNF) receptor family. Among these are five receptors for the cytotoxic ligand TRAIL (TNF-related apoptosis-inducing ligand). Two of these receptors, TRAIL-R1 and TRAIL-R2, contain classical cytoplasmic death domains and are able to transduce an apoptotic signal. The others lack functional death domains and are not able to promote cell death. Indeed, one of the receptors for TRAIL, osteoprotegerin (OPG) is a soluble protein whose activities so far have been shown to be inhibition of osteoclastogenesis and increased bone density in vivo. The existence of multiple receptors for TRAIL suggests an unexpected complexity to TRAIL-mediated biological functions. J. Leukoc. Biol. 65: 535–542; 1999.
Systemic suppression of human peripheral blood phagocytic leukocytes after whole-body UVB irradiation
Authors: Leino Lasse , Saarinen Kustaa , Kivistö Kaisa , Koulu Leena , Jansen Christer T , Punnonen Kari
Published: January 2018

We examined systemic effects of whole-body UVB irradiation on human peripheral blood phagocytes. We found that 24 h after a single erythemal dose of UVB radiation two phagocyte functions, adhesion and phagocytosis, were reduced by 50%. This functional suppression was accompanied by a significant decrease in the expression of complement receptors (CR1 and CR3) and IgG Fc receptors (FcRII and FcRIII). The greatest reduction (47%) was observed in CR3, which is important for both adhesion and phagocytosis. A kinetic analysis showed that both CR1 and CR3 levels started to decrease 15 min after the UVB exposure, reaching the lowest levels at 4.5- and 24-h time points, respectively. The down-modulation of CRs after whole-body UVB exposure was not due to a defective receptor synthesis or translocation from internal stores to plasma membrane because the maximal CR levels in stimulated cells were not affected by UVB. No change in the serum soluble ICAM-1 was detected after UVB, which rules out CD11b epitope masking by sICAM-1. UVB did not release low-receptor-density myeloid progenitor cells from storage pools into circulation. Interleukin 10, a mediator of UVB-induced immunosuppression, was unable to modulate CR expression in vitro. When seven suberythemal whole-body UVB exposures were given repeatedly within 2 weeks, a significant decrease in CR expression was seen, which was greatest after three irradiations. Our data suggest that an exposure to UVB has systemic effects in humans which, possibly due to the down-modulation of preexisting cell-surface receptors, suppress some important functions of circulating phagocytic cells. J. Leukoc. Biol. 65: 573–582; 1999.
Generation of CD28− cells from long-term-stimulated CD8+CD28+ T cells: a possible mechanism accounting for the increased number of CD8+CD28− T cells in HIV-1-infected patients
Authors: Fiorentini Simona , Malacarne Fabio , Ricotta Doris , Licenziati Stefano , Solis Adakatia Armenta , Ausenda Sabrina , De Francesco Maria , Garrafa Emirena , Simonini Andrea , Imberti Luisa , Balsari Andrea , Turano Adolfo , Caruso Arnaldo
Published: January 2018

According to CD28 molecule expression, CD8+ T cells can be classed as CD28bright, CD28dim, and CD28−. The CD28dim T cells were found to derive from mitogenic stimulated CD28− T cells but also from CD28bright T cells through a mechanism of CD28 down-modulation. Moreover, after prolonged in vitro interleukin-2 stimulation, clonal CD28bright cells showed a CD28dim expression before further evolution to a stable CD28− phenotype. This loss was concomitant with the disappearance of CD28 mRNA. A study of the cytokine production pattern revealed that CD28dim and CD28−T cell clones produced similar levels of type 1 and type 2 cytokines, which differed from those produced by the CD28bnght T cell clones. A high percentage of CD28dim and CD28− cells, with similarities in their cytokine production pattern, were found in the blood samples of HIV-infected patients, as compared to healthy donors. The CD28 down-modulation may account for the increased number of CD8+CD28− T cells in HIV-infected patients. J. Leukoc. Biol. 65: 641–648; 1999.
Increased neutrophil adherence and adhesion molecule mRNA expression in endothelial cells during selenium deficiency
Authors: Maddox Jane F , Aherne Kristen M , Reddy C Channa , Sordillo Lorraine M
Published: January 2018

Leukocyte aggregation and activation on endothelial cells (EC) are important preliminary events in leukocyte migration into tissue and subsequent inflammation. Thus, an increase in leukocyte adherence has the potential to affect inflammatory disease outcome. Selenium (Se) is an integral part of the antioxidant enzyme glutathione peroxidase (GSH-Px) and plays an important role in the maintenance of the redox state of a cell. Se supplementation in the bovine has been shown to improve the outcome of acute mastitis caused by coliform bacteria, in part by enhancing the speed of neutrophil migration into the affected mammary gland. However, the mechanisms by which Se modulates neutrophil migration have not been elucidated. Therefore, an in vitro model of Se deficiency in primary bovine mammary artery EC was used to examine the impact of Se status on the adhesive properties of EC. The effect of Se on functional activities was examined by measuring neutrophil adherence to Se-deficient and Se-supplemented EC. Se-deficient EC showed significantly enhanced neutrophil adherence when stimulated with tumor necrosis factor α (TNF-α) for 4 or 24 h, interleukin-1 for 12 h, or H2O2 for 20 min (P < 0.05). To determine the mechanisms underlying these changes in neutrophil adherence, the expression of EC adhesion molecules, ICAM-1, E-selectin, and P-selectin were examined at the molecular level by a competitive reverse transcription-polymerase chain reaction. Results revealed higher mRNA expression for E-selectin and ICAM-1 in Se-deficient EC stimulated with TNF-α for 3 and 6 h, and greater expression of P-selectin mRNA in Se-supplemented EC with 3-h TNF-α stimulation. These studies provide new information to establish the role of Se nutrition in the initiation of leukocyte adherence to endothelium. J. Leukoc. Biol. 65: 658–664; 1999.
Integrin-mediated signaling in human neutrophil functioning
Authors: Williams Mark A , Solomkin Joseph S
Published: January 2018

Integrins are important signal transducers for virtually all neutrophil functions. Although a variety of signals ultimately result in integrin activation, the intracellular targets of integrin-initiated signals are poorly delineated to date. Polymorphonuclear (PMN) leukocyte responses to inflammation are dependent on both the stimulants and the extracellular environment encountered. Integrin ligation, by cell-cell or cell-matrix interactions, activates a variety of signaling cascades. These events dictate the nature of PMN responses to the encountered stimulus. The complex system of effector molecule recruitment and permissive signaling by integrins serves to strictly regulate PMN functions such as cell adhesion, motility, oxidant production, and protein synthesis. Moreover, there is evidence that cross-talk between integrins exists to prime integrin populations for subsequent functioning. This review summarizes the current understanding of signaling mechanisms for integrin priming and activation. In this connection, the role of specific signaling molecules in key PMN functions are examined. J. Leukoc. Biol. 65: 725–736; 1999.
No detectable NO synthesis from L-arginine or NG-hydroxy-L-arginine in fMLP-stimulated human blood neutrophils despite production of nitrite, nitrate, and citrulline from NG-hydroxy-L-arginine
Authors: Holm Päivi , Kankaanranta Hannu , Oja Simo S , Knowles Richard G , Moilanen Eeva
Published: January 2018

Nitric oxide (NO) is a well-documented effector molecule in rodent phagocytes but its synthesis in human neutrophils has been controversial. In this study, NO production in human neutrophils activated by chemotactic peptide N-formyl-methionyl-leucyl-phenylalanine (fMLP) was measured in the presence of l-arginine (l-Arg) and NG-hydroxy-l-arginine (OH-l-Arg), the precursor and intermediate amino acids in NO synthesis, respectively. Incubation of fMLP-activated neutrophils with OH-l-Arg resulted in a production of nitrite, nitrate, and citrulline that was greater than with unstimulated neutrophils but was not inhibited by the NOS inhibitors l-NMMA and l-NIO or the cytochrome P450 inhibitor troleandomycin and was not seen when OH-l-Arg was replaced with l-Arg. This nitrite, nitrate, and citrulline production was not associated with any detectable NO synthesis because no increases in cyclic GMP were observed in the presence of phosphodiesterase inhibitors and in the presence or absence of superoxide dismutase. Moreover, no increases in the formation of the reaction product of NO with superoxide, peroxynitrite, were observed on addition of either OH-l-Arg or l-Arg to activated neutrophils, as assessed either by dihydrorhodamine oxidation or protein nitration. This suggests that, in spite of the production of nitrite, nitrate, and citrulline, commonly used indicators of NO formation, normal human blood neutrophils, are not producing detectable amounts of either NO or peroxynitrite when stimulated with fMLP in the presence of OH-l-Arg. J. Leukoc. Biol. 66: 127–134; 1999.
Regulatory effects of interleukin-11 during acute lung inflammatory injury
Authors: Lentsch Alex B , Crouch Larry D , Jordan Jacqueline A , Czermak Boris J , Yun Edward C , Guo Renfeng , Sarma Vidya , Diehl Kathleen M , Ward Peter A
Published: January 2018

The role of interleukin-11 (IL-11) was evaluated in the IgG immune complex model of acute lung injury in rats. IL-11 mRNA and protein were both up-regulated during the course of this inflammatory response. Exogenously administered IL-11 substantially reduced, in a dose-dependent manner, the intrapulmonary accumulation of neutrophils and the lung vascular leak of albumin. These in vivo anti-inflammatory effects of IL-11 were associated with reduced NF-κB activation in lung, reduced levels of tumor necrosis factor α (TNF-α) in bronchoalveolar lavage (BAL) fluids, and diminished up-regulation of lung vascular ICAM-1. It is interesting that IL-11 did not affect BAL fluid content of the CXC chemokines, macrophage inflammatory protein-2 (MIP-2) and cytokine-inducible neutrophil chemoattractant (CINC); the presence of IL-11 did not affect these chemokines. However, BAL content of C5a was reduced by IL-11. These data indicate that IL-11 is a regulatory cytokine in the lung and that, like other members of this family, its anti-inflammatory properties appear to be linked to its suppression of NF-κB activation, diminished production of TNF-α, and reduced up-regulation of lung vascular ICAM-1. J. Leukoc. Biol. 66: 151–157; 1999.
Intestinal inflammation in adhesion molecule-deficient mice: an assessment of P-selectin alone and in combination with ICAM-1 or E-selectin
Authors: McCafferty Donna-Marie , Smith C Wayne , Granger D Neil , Kubes Paul
Published: January 2018

Biopsy specimens from patients with inflammatory bowel disease have demonstrated an up-regulation of P-selectin, suggesting a role for P-selectin in intestinal inflammation. We examined the role of P-selectin in experimental intestinal inflammation using mice deficient in P-selectin alone or in combination with either ICAM-1 or E-selectin. Colitis was induced using acetic acid or trinitrobenzene sulfonic acid (TNBS). Damage scores and neutrophil infiltration 24 h post acetic acid were not different between wild-type and P-selectin- or P-selectin/ICAM-1-deficient mice, whereas P/E-selectin-deficient mice had enhanced leukocyte recruitment and damage. At 72 h an attenuation in damage scores and a slight decrease in neutrophil infiltration was observed in the P- and P/ICAM-deficient animals. The P/E-selectin-deficient mice maintained enhanced leukocyte recruitment and damage. In wild-type mice P-selectin expression was elevated 48 and 72 h post acetic acid-induced inflammation. Surprisingly, P-selectin or P-selectin/ICAM-1 deficiency did not improve the inflammation induced by TNBS over 7 days. In fact, increased mortality was observed. Anti-adhesion therapy may play only a limited, beneficial role and often a detrimental role in intestinal inflammation. J. Leukoc. Biol. 66: 67–74; 1999.
The leukocyte immunoglobulin-like receptors (LIRs): a new family of immune regulators
Authors: Fanger Neil A , Borges Luis , Cosman David
Published: January 2018

Identification of a counterstructure for the human cytomegalovirus-encoded major histocompatibility complex class I-related gene product, UL18, has led to the discovery of a novel family of immunoreceptors, termed leukocyte immunoglobulin-like receptors (LIRs). The LIRs are differentially expressed in cells of the dendritic cell, monocytic and lymphocytic lineages, and appear to mediate diverse roles in immune regulation. This review summarizes the expression, distribution, and signaling capacities of the LIRs and discusses possible roles of the LIRs in both inhibition and activation of the cellular responses. J. Leukoc. Biol. 66: 231–236; 1999.
Genetic engineering of dendritic cells to express immunosuppressive molecules (viral IL-10, TGF-β, and CTLA4Ig)
Authors: Lu Lina , Lee Wei-Chen , Takayama Takuya , Qian Shiguang , Gambotto Andrea , Robbins Paul D , Thomson Angus W
Published: January 2018

There is growing evidence that, in addition to their role as initiators of immune responses, dendritic cells (DC) can exhibit tolerogenic properties. Immature DC deficient in cell surface costimulatory/accessory molecules can prolong organ and pancreatic islet allograft survival, whereas in vitro manipulation of DC by exposure to a variety of factors (e.g., viral interleukin-10; CTLA4Ig) can confer tolerogenic properties on these cells. Genetic engineering of DC to express immunosuppressive molecules is, in theory, an attractive approach to the therapy of allograft rejection and possibly, autoimmune disorders. J. Leukoc. Biol. 66: 293–296; 1999.
Dendritic cells in genetic immunization
Authors: Takashima Akira , Morita Akimichi
Published: January 2018

Both humoral and cellular immune responses are inducible by inoculation of naked plasmid DNA encoding a polypeptide antigen. This new vaccination protocol, known as genetic immunization, has been used to initiate protective immunity against a variety of infectious pathogens and tumors in experimental animals. Dendritic cells (DC) are thought to play at least three distinct roles in genetic immunization: (1) MHC class II-restricted presentation of antigens secreted by neighboring, transfected cells, (2) MHC class I-restricted “cross” presentation of antigens released by neighboring, transfected cells, and (3) direct presentation of antigens by transfected DC themselves. Several new technologies have been developed recently in an attempt to improve the overall efficacy of genetic vaccination, as well as to regulate the type and class of resulting immune responses. These technologies include modification of plasmid DNA, co-delivery of genes encoding immunoregulatory molecules, and DC targeting. We will overview some of these new technologies in genetic immunization. J. Leukoc. Biol. 66: 350–356; 1999.
Regulation of leukocyte adherence and migration by glycosylphosphatidyl-inositol-anchored proteins
Authors: Sendo Fujiro , Araki Yoshihiko
Published: January 2018

Leukocyte extravasation is essential for subsequent inflammation and the immune response. Extravasation can be divided into at least three steps; rolling, firm adhesion, and transendothelial migration. Although the mechanisms involved in the first two steps have been fairly well documented, the last step is complex and largely remains to be clarified. This review focuses on the possible role of GPI-anchored proteins on leukocytes in the regulation of their transendothelial migration. In addition to regulation by urokinase and its receptor, which has been regarded as the main modulator, we draw attention to a novel GPI-anchored protein (GPI-80) on human phagocytes that may be involved in regulating leukocyte adhesion and migration. The high degree of homology of GPI-80 with vanin-1, which is expressed on vascular tissues and is involved in prethymic cell homing into the thymus, raises the possibility that there is a family of molecules, including GPI-80 and vanin-1, that may be involved in leukocyte transendothelial migration. The possible role of soluble GPI-anchored proteins in this process is also discussed. J. Leukoc. Biol. 66: 369–374; 1999.
Endogenous IL-15 might be responsible for early protection by natural killer cells against infection with an avirulent strain of Salmonella choleraesuis in mice
Authors: Hirose Kenji , Nishimura Hitoshi , Matsuguchi Tetsuya , Yoshikai Yasunobu
Published: January 2018

Interleukin (IL)-15 is a novel cytokine with growth factor activity for T cells, B cells, and natural killer cells (NK cells). We investigated the role of IL-15 in the host defense against infection with avirulent Salmonella choleraesuis strain 31N-1 cured of 50-kb virulent plasmid. IL-15 was abundantly expressed at transcription and protein levels in macrophages infected with S. choleraesuis 31N-1. The number of NK cells in the infected sites was increased during the course of infection coincident with IL-15 production. Anti-IL-15 mAb administration inhibited the emergence of NK cells and interferon-γ (IFN-γ) production in serum after infection with S. choleraesuis 31N-1 and concurrently impaired the clearance of the bacteria. These results suggested that IL-15 might be responsible for protection against avirulent S. choleraesuis infection at early stage of infection through activation of NK cells in the infected sites. J. Leukoc. Biol. 66: 382–390; 1999.
Neutrophil activation in sickle cell disease
Authors: Lard L R , Mul F P J , de Haas M , Roos D , Duits A J
Published: January 2018

Vascular occlusion is the main cause of the morbidity and mortality observed in patients with sickle cell disease (SCD). Increasing evidence indicates that (activated) neutrophils could play an important role in the initiation and propagation of vaso-occlusive processes in SCD. In this study, the activation state of neutrophils in sickle cell patients was analyzed by determining the level of expression of neutrophil antigens such as CD62L, CD11b, CD66b, CD63, and Fcγ receptors. We also analyzed plasma levels of lactoferrin, elastase, soluble (s)CD16 (sFcγRIII), and serum levels of soluble (s)CD62L (sL-selectin) as neutrophil activation markers in these patients. Significant differences were observed in the activation state of neutrophils in non-symptomatic sickle cell patients compared to healthy HbAA controls as exemplified by significant decrease in L-selectin expression, enhanced expression of CD64, and increased levels of soluble markers like sL-selectin, elastase, and sCD16. During vaso-occlusive crisis the differences were even more pronounced. These results show neutrophils to be activated in sickle cell patients, suggesting a role of importance in the pathophysiology of sickle cell disease. J. Leukoc. Biol. 66: 411–415; 1999.
Digestion of C1q collagen-like domain with MMPs-1, -2, -3, and -9 further defines the sequence involved in the stimulation of neutrophil superoxide production
Authors: Ruiz S , Henschen-Edman A H , Nagase H , Tenner A J
Published: January 2018

C1q, a subunit of the first component (C1) of the classical complement pathway, binds to neutrophils via its collagen-like region (C1q-CLR) stimulating superoxide production. We previously identified a region of C1q-CLR, defined by fragments generated by trypsin and endoLys-C digestion, that was required for triggering this respiratory burst. To further localize that critical site, purified human C1q was digested with pepsin to generate C1q-CLR, and subsequently cleaved with the matrix metalloproteinases, MMP-1, MMP-2, MMP-3, and MMP-9. Digestion of C1q-CLR with any of these MMPs did not alter the circular dichroism spectra, demonstrating that the fragments generated had maintained the secondary structure observed in the native molecule. All fragments retained the ability to trigger superoxide production by neutrophils. Analysis of the amino acid sequences of the purified cleavage products (none of which are identical to the published cleavage site specificities for these enzymes) demonstrated that it is the C-chain, but not the A-chain of C1q, that is critical for stimulating this activity, and thus may be a target for future therapeutic intervention. J. Leukoc. Biol. 66: 416–422; 1999.
SLC/Exodus2/6Ckine/TCA4 induces chemotaxis of hematopoietic progenitor cells: differential activity of ligands of CCR7, CXCR3, or CXCR4 in chemotaxis vs. suppression of progenitor proliferation
Authors: Kim Chang H , Broxmeyer Hal E
Published: January 2018

Chemokines induce chemotaxis of hematopoietic progenitor cells (HPC), and suppress their proliferation. In this study we report that SLC/Exodus2/6Ckine/TCA4 (hereafter termed SLC) is a chemoattractant for human CD34+ HPC. SLC mainly induces preferential chemotaxis of macrophage progenitors. We examined the chemotactic activity of CXCR3 ligands on CD34+ HPC because it has been reported that SLC is a potential ligand of CXC chemokine receptor, CXCR3, in addition to a CC chemokine receptor, CCR7. It was found that the CXCR3 ligands, MIG and interferon-γ inducible protein-10 (IP-10), unlike SLC, did not induce chemotaxis of CD34+ HPC. In this regard, CCR7 ligands (SLC and CKβ-11), but not IP-10 and MIG, induce actin polymerization in CD34+ cells. On the other hand, CCR7 ligands and CXCR3 ligands, but not the CXCR4 ligand SDF-1, showed inhibitory activity for proliferation of myeloid progenitor cells. Our results suggest that SLC is a potential trafficking factor for HPC, and that chemokines that bind CCR7, CXCR4, and CXCR3 have differential biological activities on HPC in terms of suppression and chemotaxis. J. Leukoc. Biol. 66: 455–461; 1999.
Transcriptional control of the human MCP-2 gene promoter by IFN-γ and IL-1β in connective tissue cells
Authors: van Coillie Els , van Aelst Ilse , Fiten Pierre , Billiau Alfons , van Damme Jo , Opdenakker Ghislain
Published: January 2018

Human monocyte chemotactic protein-2 (MCP-2) is a member of the CC chemokine family. It is produced by mononuclear leukocytes, diploid fibroblasts, and tumor cells after induction with IL-1β or IFN-γ. To understand the transcriptional regulation of the gene, we have analyzed the structure and function of the promoter region. The sequence of the 5′-flanking region was determined and the transcription start site was found to be located at 68 nucleotides upstream of the ATG translation start codon. 5′-Deletion mutants were generated and transfected into E6SM diploid fibroblasts and MG-63 osteosarcoma cells. Expression was measured by luciferase assay in transfected unstimulated cells and after stimulation with IL-1β, IFN-γ, or a combination. The region between nucleotides -143 and -73 (relative to the transcription initiation site), containing putative cis-elements for GATA-1, H-APF1, AP-1, and GAS, is important for basal transcription levels in both cell lines. Stimulation for 18 h with IL-1β alone failed to affect expression of any of the constructs both in diploid fibroblasts and in osteosarcoma cells. In both cell lines IFN-γ increased the activity of all mutants that possessed the region between -340 and -301. In MG-63 cells, stimulation with the combination of IL-1β and IFN-γ caused an additional increase in expression of the constructs from -340 onward. Finally, the presence of transcription factors in nuclear extracts of MG-63 cells and their specificity to bind to various oligonucleotide probes in this [-340; -301] region were evidenced by electromobility shift assays. These results show that IFN-γ, produced by lymphocytes and NK cells, induces the transcription of the MCP-2 gene in fibroblasts and thereby can indirectly contribute to recruitment of various leukocyte cell types to inflammatory sites. J. Leukoc. Biol. 66: 502–511; 1999.
Ly-49 receptor expression and functional analysis in multiple mouse strains
Authors: Ortaldo John R , Mason Anna T , Winkler-Pickett Robin , Raziuddin Arati , Murphy William J , Mason Llewellyn H
Published: January 2018

We present data on the strain distribution and functional characteristics of the Ly-49 receptors A, C/I, D, and G2 on DX5+ natural killer (NK) cells. We have examined tyrosine phosphorylation of the Ly-49 molecules, regulation of NK cytotoxic functions, and in vivo marrow rejection capability. The flow cytometry results demonstrate a diverse and complex pattern of expression of the Ly-49 receptors in the 11 strains examined. The vast majority of NK cells express Ly-49s, although some NK1.1+ CD3+ cells also express these receptors. The results of our functional analysis indicate that H-2Dd was able to inhibit the function of Ly-49G2+ NK cells, not only in B6 mice, but also by NK cells derived from several haplotypes. The examination of Ly-49 receptor tyrosine phosphorylation, which is a biochemical measure of inhibitory function, was consistently observed in the 11 mouse strains examined. In contrast, analysis of Ly-49D function suggests its expression appears to be more restricted and that H-2Dd is an activating ligand for this receptor. In addition, the in vivo examination of both inhibitory (Ly-49G2) and activating (Ly-49D) receptors demonstrated regulatory roles of these class I binding receptors in marrow transplantation. J. Leukoc. Biol. 66: 512–520; 1999.
Inflammatory processes in a murine model of intra-abdominal abscess formation
Authors: Finlay-Jones John J , Davies Kate V L , Sturm Lana P , Kenny Peter A , Hart Prue H
Published: January 2018

Abscess formation has been viewed as a host defense strategy to contain the spread of infection. However, abscesses are also serious and life-threatening manifestations of persisting microbial infection. The initiation of abscess formation, both clinically and experimentally, involves the release of bacteria and an abscess-potentiating agent (e.g., fecal fiber or an analog) into a sterile site, with host defense mechanisms being unable to eliminate the infecting organisms. Abscess formation is aided by a combination of factors that share a common feature: impairment of phagocytic killing and hence clearance of microorganisms. These include bacterial virulence factors (e.g., capsule formation, succinic acid production); complement activation by the abscess potentiating agent; fibrin deposition; and microbial sequestration within abscess neutrophils. Recruitment of cells into the peritoneal cavity follows mast cell activation in the pathogenesis of infection: histamine and tumor necrosis factor α can be detected in the peritoneal cavity within minutes of challenge with an abscess-inducing mixture. However, the role of mast cells in host defense is made less clear by the finding of diminished abscess formation (but no mortality or increased morbidity) in mast-cell-depleted mice. This may indicate that mast cell products have a role in not only the initiation of an inflammatory response but also the promotion of fibrin deposition and abscess formation. J. Leukoc.Biol. 66: 583–587; 1999.
Characterization of the biosynthesis, processing, and sorting of human HBP/CAP37/azurocidin
Authors: Lindmark Anders , Garwicz Daniel , Rasmussen Poul B , Flodgaard Hans , Gullberg Urban
Published: January 2018

Azurocidin is a multifunctional endotoxin- binding serine protease homolog synthesized during the promyelocytic stage of neutrophil development. To characterize the biosynthesis and processing of azurocidin, cDNA encoding human preproazurocidin was stably transfected to the rat basophilic leukemia cell line RBL-1 and the murine myeloblast-like cell line 32D cl3; cell lines previously utilized to study the related proteins cathepsin G and proteinase 3. After 30 min of pulse radiolabeling, two forms of newly synthesized proazurocidin (34.5 and 37 kDa), differing in carbohydrate content but with protein cores of identical sizes, were recognized. With time, the 34.5-kDa form disappeared, while the 37-kDa form was further processed proteolytically, as judged by digestion with N-glycosidase F. Conversion of high-mannose oligosaccharides into complex forms was shown by acquisition of complete resistance to endoglycosidase H. Radiosequence analysis demonstrated that the amino-terminal seven amino acid propeptide of proazurocidin was removed in a stepwise manner during processing; initial removal of five amino acids was followed by cleavage of a dipeptide. Presence of the protease inhibitors Gly-Phe-diazomethyl ketone, bestatin, or leupeptin inhibited only the cleavage of the dipeptide, thus indicating the involvement of at least two amino- terminal processing enzymes. Translocation of azurocidin to granules was shown by subcellular fractionation. Similar results, with efficient biosynthesis, processing, and targeting to granules in both cell lines, were obtained with a mutant form of human preproazurocidin lacking the amino-terminal heptapropeptide. In conclusion, this investigation is an important addition to our previous studies on related azurophil granule proteins, and provides novel information concerning the biosynthesis and distinctive amino-terminal processing of human azurocidin. J. Leukoc. Biol. 66: 634–643; 1999.
MIP-3α induces human eosinophil migration and activation of the mitogen-activated protein kinases (p42/p44 MAPK)
Authors: Sullivan Susan K , McGrath Douglas A , Liao Fang , Boehme Stefen A , Farber Joshua M , Bacon Kevin B
Published: January 2018

The CC chemokine macrophage inflammatory protein-3α (MIP-3α) is the product of recent electronic cloning efforts, however, little characterization of its spectrum of biological effects has been undertaken. Human eosinophils exhibited pertussis-toxin-sensitive migration in response to human recombinant (hr)MIP-3α. Messenger RNA for the MIP-3α receptor, CCR-6, and low levels of surface expression were demonstrated by reverse transcriptase-polymerase chain reaction and FACS analysis. Analyses of cell signaling revealed dose-dependent increases in intracellular calcium mobilization, calcium transients that were, however, greatly reduced when compared with MCP-3-induced responses. Further investigations of MIP-3α-induced signal transduction revealed time- and dose-dependent, partially pertussis toxin-dependent, increases in phosphorylation of the p42/p44 mitogen-activated protein kinases (MAPK) that occurred at 10- to 100-fold lower concentrations, and that were linked to a phosphoinositide 3-kinase pathway. These results suggest that MIP-3α can regulate multiple, parallel signal transduction pathways in eosinophils, and suggest that MAPK activation by MIP-3α in eosinophils is a significant signaling pathway for migration induction. J. Leukoc. Biol. 66: 674–682; 1999.
C/EBP regulates the promoter of the eosinophil-derived neurotoxin/RNS2 gene in human eosinophilic cells
Authors: Baltus Belinda , Buitenhuis Miranda , van Dijk Thamar B , Vinson Charles , Raaijmakers Jan A M , Lammers Jan-Willem J , Koenderman Leo , de Groot Rolf P
Published: January 2018

The eosinophil-derived neurotoxin (EDN), a member of the mammalian ribonuclease family, is found in the large specific granules of human eosinophilic leukocytes. We have investigated the role of the C/EBP transcription factor family in the regulation of EDN promoter activity. Here we show that the C/EBP family is involved in intrinsic regulation of EDN promoter activity. We have identified a C/EBP binding site located at – 124 in the proximal promoter of the EDN gene. Mutation of this C/EBP site results in a decrease of promoter activity in HL-60-eos cells as well as in eosinophils differentiated in vitro from CD34+ cells. Different C/EBP proteins are able to bind to the C/EBP site as shown by gel shift assay. Our results indicate the importance of the C/EBP family in the regulation of the EDN gene in eosinophils. J. Leukoc. Biol. 66: 683–688; 1999.
Migration of leukocytes across endothelium and beyond: molecules involved in the transmigration and fate of monocytes
Authors: Muller William A , Randolph Gwendalyn J
Published: January 2018

Passage of leukocytes across the endothelial lining into sites of inflammation has been shown to be regulated largely by platelet/endothelial cell adhesion molecule-1 (PECAM/CD31). We summarize recent work from our laboratory documenting that PECAM is involved both in diapedesis and the subsequent step of migration across the basal lamina. The former process involves a homophilic interaction between the amino-terminal extracellular domains of PECAM on the leukocyte and on the endothelial cell. The latter process involves a heterophilic interaction between the membrane-proximal extracellular domain of PECAM and an unknown ligand(s) in the subendothelial basal lamina. These findings are demonstrated in both in vitro and in vivo models. For monocytes, however, transmigration is just the first step in the next phase of their lives. In addition to their specific recruitment during the inflammatory response, many monocytes constitutively leave the bloodstream to enter tissues. However, only a fraction of these become tissue macrophages. In an in vitro model of monocyte emigration, approximately half of the leukocytes that initially transmigrate an endothelial monolayer migrate back out in the basal-to-apical direction within the next 2 days. This reverse transmigration cannot be blocked by anti-PECAM reagents, but involves p-glycoprotein and tissue factor expressed on the leukocytes. The reverse transmigrating cells are phenotypically dendritic cells (DC). Their maturation to mature DC can be accelerated by inclusion of inflammatory stimuli in the co-culture. The cells that remain behind in the subendothelial collagen are phenotypically macrophages. We postulate that a major source of DC in lymph nodes is cells derived from monocytes that enter a tissue via the blood and leave several days later via afferent lymphatic channels. J. Leukoc. Biol. 66: 698–704; 1999.
Modular components of phagocytosis
Authors: Greenberg Steven
Published: January 2018

Phagocytosis is an evolutionarily ancient host cell endocytic response to particulate stimuli. Phagocytic leukocytes utilize highly conserved programs of signaling and motility to engulf foreign pathogens. Particle ingestion requires actin assembly and pseudopod extension, two cellular events that coincide spatially and temporally. This review presents evidence that phagocytosis proceeds in discrete but coordinated stages. In the case of receptors for the Fc portion of IgG (FcγRs), engagement of the IgG ligands results in receptor aggregation and recruitment of cytosolic tyrosine kinases, most notably Syk. Phosphorylation of tyrosine residues occurs within immunoreceptor tyrosine activation motif (ITAM) consensus sequences found in FcγR subunits, which leads to further recruitment and activation of Syk via its SH2 domains. Syk tyrosine kinase activity is required for FcγR-mediated actin assembly, which is controlled by several GTPases, including Rac1 and Cdc42. Phagocytosis and Rac-mediated cytoskeletal alterations also require the participation of another low molecular GTPase, ARF6. Simultaneously, phosphati-dylinositol 3-kinase is recruited to the plasma membrane, which triggers exocytosis from an intracellular membrane source that is required for pseudopod extension. The source of this membrane is as yet unknown. This review focuses on individual components of phagocytosis and emphasizes that the signaling requirements for each of these is distinct. J. Leukoc. Biol. 66: 712–717; 1999.
Macrophage scavenger receptors and foam cell formation
Authors: de Villiers Willem J S , Smart Eric J
Published: January 2018

Scavenger receptors bind and internalize modified low-density lipoprotein (LDL) and high-density lipoprotein (HDL). Because the expression of scavenger receptors is not down-regulated by cholesterol, macrophages (M) expressing scavenger receptors can internalize substantial quantities of cholesteryl ester from oxidized LDL and HDL, leading to foam cell formation. M express several different classes of the growing scavenger receptor family on their cell surface and their relative contribution to M cholesterol physiology and atherogenesis is the subject of intense investigation. We focus on the potential role of two scavenger receptors, macrosialin and SR-BI/II in M cholesterol metabolism. Macrosialin is a predominantly M-specific oxidized LDL-binding protein and an atherogenic diet markedly up-regulates its hepatic expression in atherosclerosis-susceptible and atherosclerosis-resistant mouse strains. The HDL receptor, SR-BI and its splicing variant SR-BII, colocalize with caveolin in caveolae in M. Caveolae are initial acceptor sites for cholesteryl esters and these findings indicate a possible role for caveolae and SR-BI in M-selective lipid uptake and in regulating M cholesterol flux in the vascular wall. J. Leukoc. Biol. 66: 740–746; 1999.
Intracellular niches for extracellular bacteria: lessons from Helicobacter pylori
Authors: Allen Lee-Ann H
Published: January 2018

Helicobacter pylori colonizes the gastric epithelium of humans and plays a causative role in peptic ulcer disease and perhaps gastric cancer. H. pylori proliferates in the mucus layer over the epithelium and is not cleared by the host immune response. Although the mucus layer is the major reservoir of H. pylori in vivo, a growing body of evidence suggests that H. pylori can persist in multiple intracellular locales. Clinical isolates of H. pylori invade epithelial monolayers at least as well as Shigella. The intracellular organisms are cytotoxic, and bacterial microcolonies form on the exposed basement membrane. Both mononuclear phagocytes and neutrophils phagocytose unopsonized H. pylori. However, the internalized organisms are not killed efficiently and our recent data suggest that H. pylori disrupts phagosome maturation. Collectively, the data support the hypothesis that intracellular H. pylori represent a reservoir of organisms that contributes to bacterial persistence, host tissue damage, and treatment failure. J. Leukoc. Biol. 66: 753–756; 1999.
Interleukin-1 production by mouse macrophages is regulated in a feedback fashion by nitric oxide
Authors: Obermeier Florian , Gross Volker , Schölmerich Jürgen , Falk Werner
Published: January 2018

The pleiotropic cytokine interleukin-1 (IL-1) is an inducer of the inducible nitric oxide synthase (iNOS). It was surprising to find that treatment of normal mice with an iNOS inhibitor resulted in detectable IL-1β mRNA in colon and spleen, suggesting feedback regulation. When mouse peritoneal exudate cells (PEC) or RAW 264.7 cells were stimulated with lipopolysaccharide (LPS), concomitant inhibition of iNOS resulted in an increase of IL-1β and IL-1α protein secretion. Conversely, after addition of the NO-generating compound NOC-18, IL-1β and IL-1α concentrations in supernatants were dose-dependently reduced. Co-stimulation with interferon-γ (IFN-γ) reversed the NOC-18-mediated suppression of IL-1α protein concentration into an almost fivefold increase in RAW 264.7 cells. This effect was specific for IL-1α and was also seen in PEC. The mRNA expression for IL-1β and IL-1α in RAW 264.7 cells correlated with the protein levels, suggesting transcriptional regulation by NO. Dysregulated IL-1/NO cross-regulation may play a role in inflammatory diseases. J. Leukoc. Biol. 66: 829–836; 1999.
Macrophage responses to hypoxia: relevance to disease mechanisms
Authors: Lewis J S , Lee J A , Underwood J C E , Harris A L , Lewis C E
Published: January 2018

Macrophages are ubiquitous in the stromal compartment of tissues under normal physiological conditions and the number of these cells increases markedly with the onset and progression of many pathological states. The mechanisms underlying this response are well described in such conditions as wound healing and malignant tumors, where tissue-specific signals enhance the extravasation of blood monocytes and their subsequent differentiation into macrophages. Recent evidence suggests that macrophages may also be stimulated by microenvironmental factors present in diseased tissues to perform distinct, tissue-specific activities. One such factor, hypoxia (low oxygen tension), results from insufficient vascular perfusion of a given tissue. Various studies have shown that experimental hypoxia alters the morphology, expression of cell surface markers, viability, phagocytosis, metabolic activity, and release of cytokines by macrophages. Here we review the evidence for these macrophage responses to hypoxia, the involvement of co-stimuli, and their implications for the role of macrophages in various disease processes. Because the intracellular mechanisms mediating the effects of hypoxia on gene expression in other cell types have been characterized recently, we discuss their possible involvement in the effects of hypoxia on gene expression in macrophages. J. Leukoc. Biol. 66: 889–900; 1999.
Functional expression of CD43 on human natural killer cells
Authors: Aguado Enrique , Santamaría Manuel , Gallego María Dolores , Peña José , Molina Ignacio J
Published: January 2018

CD43 is the major leukocyte sialoglycoprotein that plays important functional roles in neutrophils and lymphocytes. However, the expression of CD43 on human natural killer (NK) cells and its participation in the regulation of NK activity has not been studied. We have therefore investigated the expression of CD43 isoforms on human NK cell subpopulations as well as the role of this molecule in NK cell activation and cytotoxicity. We found that CD56bright and CD56dim NK cells express different sialylated forms of CD43, observing that activation of the CD56bright NK cells induces the change of tetrasaccharide O-glycans to hexasaccha-ride O-glycans on CD43. Cross-linking of the molecule with mAbs results in a metalloprotease-dependent loss of CD43 from the NK cell surface, whereas soluble anti-CD43 mAbs induce a vigorous NK cell proliferation. This property is distinct from T cells, which proliferate after CD43 cross-linking only in the presence of monocytes. Occupancy of the CD43 receptor on NK cells transduces specific signals, leading to enhanced killing activity and tyrosine phosphorylation and de-phosphorylation of several substrates. We therefore propose that CD43 significantly contributes to the regulation of the NK cell function by participating in the control of effector/target interactions and, if pertinent, by transducing activation signals. J. Leukoc. Biol. 66: 923–929; 1999.
Human polymorphonuclear neutrophils express a B7-1-like molecule
Authors: Windhagen Anja , Maniak Susanna , Gebert Andreas , Ferger Isabel , Wurster Ulrich , Heidenreich Fedor
Published: January 2018

Polymorphonuclear neutrophils (PMN) are part of the innate immune system and are first-line effector cells in acute inflammatory responses. On activation PMNs secrete cytokines and oxygen metabolites that might be involved in the regulation of the acquired immune response. We show here that peripheral blood PMNs constitutively express a B7-1-like molecule as detected by immunostaining with several B7-1 antibodies. Reverse transcriptase-polymerase chain reaction using three sets of primers spanning different regions of B7-1 indicate dissimilarities at the mRNA level. B7-1 mRNA is expressed in bone marrow cells and lipopolysaccharide (LPS)-stimulated but not in unstimulated PMNs. The B7-1-like molecule is localized to the cytoplasmic granules and translocated to the cell surface after stimulation with LPS or interleukin-12 in some donors. Binding of CTLA4-Ig suggests that the B7-1-like molecule can interact with functional B7 ligand and might be important in the immunobiology of PMNs. J. Leukoc. Biol. 66: 945–952; 1999.