bluuebunny/crossref_metadata_2025 huggingface dataset:
Accumulation of unintegrated circular viral DNA in monocytes and growth-arrested T cells following infection with HIV-1
Authors: Sonza Secondo , Kiernan Rosemary E , Maerz Anne L , Deacon Nicholas J , McPhee Dale A , Crowe Suzanne M
Published: January 2018

Cytocidal retrovirus infection is characterized by rapid accumulation of unintegrated viral DNA forms. These are thought to be generated by multiple rounds of reinfection and have been suggested to play a central role in cytopathogenesis. Here we have reviewed the work done in this area with HIV-1, mostly using acutely and chronically infected T cell and monocytic cell lines and in some cases T cells blocked at S phase of the cell cycle by aphidicolin treatment. To these studies, we have compared our findings with HIV-1 infected primary peripheral blood monocyte-derived macrophages and untreated and growth-arrested MT-2 cells, two biologically disparate cell populations. Using 1- and 2-long terminal repeat (LTR) circular forms as indicators of unintegrated viral DNA, we found similar rapid accumulation in both untreated and growth-arrested MT-2 cells. In contrast, we found much lower levels in monocyte/macrophages. Our findings suggest that accumulation of unintegrated viral DNA does not require virus production and reinfection in growth-arrested T cells. The significantly lower levels found in monocyte/macrophages may reflect superinfection resistance, allowing the maintenance of a persistent infection. J. Leukoc. Biol. 56: 289–293; 1994.
The high-output nitric oxide pathway: role and regulation
Authors: Xie Qiao-wen , Nathan Carl
Published: January 2018

Nitric oxide synthase (NOS) catalyzes the production of nitric oxide (NO), a short-lived radical gas with physiological or pathophysiological roles in nearly every organ system. The inducible NO synthase (iNOS) is a high-output isoform compared to the two constitutive NOSs. The iNOS from murine macrophages tightly binds calmodulin as a subunit, and its activity is not dependent on exogenous calmodulin or elevated calcium. This iNOS is induced at the transcriptional level by bacterial lipopolysaccharide (LPS) and interferon-γ. The promoter region of the murine iNOS gene contains at least 24 oligonucleotide motifs corresponding to elements involved in the binding of transcription factors in the promoters of other cytokine-inducible genes. Nuclear factor NF-xB/c-rel, interacting with cycloheximide-sensitive protein(s) and binding to the NF-xBd site in the iNOS promoter, controls the induction of iNOS by LPS. However, iNOS is also regulated posttranscriptionally. Complex regulation of iNOS at multiple levels may reflect the dual role of iNOS in host defense and autotoxicity. J. Leukoc. Biol. 56: 576–582; 1994.
Retention of phagocytic functions in cryopreserved human monocytes
Authors: Hansen John-Bjarne , Halvorsen Dag Seeger , Haldorsen Bjørg Christina , Olsen Randi , Sjursen Haakon , Kierulf Peter
Published: January 2018

Phagocytosis and respiratory burst activity were measured by flow cytometry in fresh and cryopreserved human monocytes, after ingestion of Escherichia coli and Staphylococcus aureus. Mononuclear leukocytes, isolated from 15 healthy donors, were divided into two portions, of which one was examined immediately and the other was cryopreserved for 3 weeks. Morphological characteristics and expression of receptors involved in phagocytosis were similar in fresh and cryopreserved monocytes. Furthermore, both internalization of bacteria and respiratory burst activity remained unchanged after cryopreservation. Transmission electron microscopy confirmed actual internalization of bacteria and not merely bacterial attachment to monocytes. Monocytes were demonstrated to retain integral cellular functions during cryopreservation. This may imply that the method has potential for use in basal and clinical trials. J. Leukoc. Biol. 57: 235–241; 1995.
Enhancement in accessibility to macrophages by modification of mucin-type carbohydrate chains on a tumor cell line: role of a C-type lectin of macrophages
Authors: Sakamaki Toshiyuki , Imai Yasuyuki , Irimura Tatsuro
Published: January 2018

We investigated the role of mucin-type (O-linked) carbohydrate chains of tumor target cells in the recognition by macrophages through a Gal/GalNAc-specific calcium-dependent lectin. Binding of a soluble form of this lectin to P815 mastocytoma cells was increased by treatment with benzyl-GalNAc, which presumably inhibited the extension of mucin-type carbohydrate chains. The levels of cell surface expression of GalNAc residues were elevated after benzyl-GalNAc treatment, as revealed by the binding of Vicia villosa agglutinin B4 and Dolichos biflorus agglutinin. Adhesion of treated P815 cells to this lectin immobilized on plastic surfaces also increased. Furthermore, the binding of P815 cells to macrophage-like RAW 264.7 cells and to peritoneal macrophages also increased after the same treatment. We concluded that elevated levels of cell surface terminal GalNAc in mucin-type carbohydrate chains increased accessibility of P815 cells to macrophages through Gal/GalNAc-specific calcium-dependent lectins. J. Leukoc. Biol. 57: 407–414; 1995.
Blood, sweat, and chemotactic cytokines
Authors: Murphy Philip M
Published: January 2018

Cytokine actions can be physiological, pharmacological, or toxic, depending on the concentration that is available and the cell type and host organism studied. Because they operate in vivo in complex networks, the salutary functions of any one cytokine can sometimes be difficult to pin down. Such has been the case for interleukin-8 (IL-8) and related members of the family of chemotactic cytokines or chemokines that are best known for their powerful effects on blood leukocytes [1]. Instead, considerable evidence from animal studies has incriminated IL-8 as a major mediator of acute, neutrophil-dependent inflammatory pathology [2]. Other chemokines have also been implicated in inflammatory injury, although the demonstration of guilt is thus far by association.
Differential regulation of fyn-associated protein tyrosine kinase activity by macrophage colony-stimulating factor (M-CSF) and granulocyte-macrophage colony-stimulating factor (GM-CSF)
Authors: Li Yan , Chen Ben
Published: January 2018

The proliferation and differentiation of macrophages are regulated by, among others, GM-CSF and M-CSF. Treatment of bone marrow nonadherent (NA) cells with M-CSF induced a greater percentage of NA cells into adherent cells, recognized as monocyte/macrophages, than did GM-CSF. The effect of GM-CSF and M-CSF on the activation of fyn kinase, a 59-kDa src family-related protein tyrosine kinase (PTK), was studied. Control cultures of bone marrow NA cells expressed only minimal levels of fyn kinase activity. Treatment of bone marrow NA cells with M-CSF, but not GM-CSF, for 12 to 24 h greatly enhanced the levels of fyn kinase activity. The effect of M-CSF on the activation of fyn kinase was further investigated using bipotential adherent bone marrow-derived macrophages (BMDMs) that coexpress receptors for both GM-CSF and M-CSF. BMDMs can be induced by either growth factor to undergo extensive proliferation in vitro. Compared to bone marrow NA cells, BMDMs displayed higher levels of basal fyn kinase activity, which were similarly elevated by M-CSF but not GM-CSF treatment. The role of fyn kinase in regulating cell adhesion was investigated by growing BMDMs in both tissue culture and Teflon flasks. The growth of BMDMs was anchorage independent; the majority of them continued to proliferate as cell suspension in Teflon flasks. Whereas the levels of fyn kinase activity in adherent BMDMs grown in tissue culture flasks increased steadily, those in BMDMs grown in Teflon flasks diminished. To study the role of fyn kinase in growth regulation, BMDMs were treated with c-fyn sense and antisense s-oligos. In the presence of c-fyn antisense s-oligos, the proliferative response of BMDMs to M-CSF but not GM-CSF was inhibited. In contrast, the proliferation of BMDM in response to either GM-CSF or M-CSF was not influenced by c-fyn sense s-oligos. Collectively, our data suggest that the activation of fyn kinase is closely associated with the acquisition of adherent capacity in maturing macrophages. J. Leukoc. Biol. 57: 484–490; 1995.
TNF-α stimulates increased plasma membrane guanine nucleotide binding protein activity in polymorphonuclear leukocytes
Authors: Klein Jon B , Scherzer Janice A , Harding George , Jacobs Alfred A , McLeish Kenneth R
Published: January 2018

TNF-α enhances the response of polymorphonuclear leukocytes (PMN) to chemoattractants: however, the mechanism by which this occurs is unclear. We addressed the hypothesis that TNF-α enhances the PMN response to chemoattractants by increasing chemoattractant receptor transmembrane signaling, using fMLP as the model chemoattractant. fMLP-stimulated guanine nucleotide binding (G) protein activation was significantly increased in plasma membranes isolated from PMNs exposed to TNF-α 100 U/ml for 10 minutes (TNF-M), compared to membranes from control cells (CM). Formyl peptide receptor number and affinity were not significantly different in CM and TNF-M. Gi and G3 content were increased in TNF-M as measured by pertussis toxin and cholera toxin (CT) catalyzed ADP-ribosylation, respectively. The increased Gi was coupled to the formyl peptide receptor as shown by receptor-specific CT labeling of Gi. Immunoblot analysis showed that both Gαi2 and Gα3 were increased in TNF-M. The functional activity of the increased G protein content was demonstrated by increased NaF-stimulated phospholipase D activity in TNF-α-treated PMNs. We conclude that TNF-α rapidly stimulates increased PMN plasma membrane expression of G proteins that couple formyl peptide receptors to effector enzymes. Regulation of G protein expression may be a significant mechanism by which TNF regulates PMN function. J. Leukoc. Biol. 57: 500–506; 1995.
CD11/CD18-independent transendothelial migration of human polymorphonuclear leukocytes and monocytes: involvement of distinct and unique mechanisms
Authors: Issekutz Andrew C , Chuluyan H Eduardo , Lopes Nancy
Published: January 2018

Monocytes and polymorphonuclear leukocytes (PMNLs) migrate across cytokine (interleukin-1, tumor necrosis factor) activated endothelium or unstimulatcd endothelium in response to chemotactic factors in vitro and in vivo utilizing the CD11/CD18 (i.e., β  2 integrin) adhesion molecule complex. However, in vivo studies have suggested that under some conditions and/or in certain tissues, leukocyte migration can also proceed via CD11/CD18-independent mechanisms. Here we com pared adhesion mechanisms involved in the migration of 51Cr-Iabeled blood monocytcs and PMNLs across human umbilical vein endothelium (HUVE) monolayers. We ob served that monocyte transendothelial migration was not inhibited by monoclonal antibody (mAb) to CD18, when the HUVE was activated with IL-1 and the chemotactic factor C5a induced the migration. This CD18-independent monocyte migration was blocked by treatment of the monocyte with mAb to β  1, orα  4 integrin, suggesting that very late activation antigen 4 (VLA-4) on the monocyte served as the alternative migration mechanism. In con trast to monocytes, mAb to CD18 inhibited PMNL migration to C5a across IL-l-aetivated HUVE, but only by 66%, significantly less than with C5a alone (84%) or IL-l-aetivated HUVE alone (95%). The migration of anti-CD18 mAb-treated PMNLs was not inhibited by function-blocking mAbs to sialyl Lewis*, L’Selectin, β  1 or of4 integrin, the β  3-related leukocyte response integrin, IL-8, or platelet-activating factor (PAF) antagonists, alone or in combination. Antibody-blocking studies of the ligands on HUVE indicated that E-selectin may be partially involved in this CD18-independent PMNL migration but that ICAM-1, VCAM-1, PECAM-1, and P-sclectin are not involved. Of several chemotactic factors tested, C5a and C5adesArg in activated plasma were the most active in inducing CD18-independent migration of PMNLs across IL-l-aetivated HUVE. These results demonstrate that (1) monocytes can utilize VLA-4 for op timal transendothelial migration and (2) PMNLs may have a novel CDl8-independent migration mechanism that is activated by C5a in conjunction with one or more ligands on cytokine-activated endothelium. This may in volve, in part, E-selectin interacting with a yet to be identified counterreceptor on PMNLs. J. Lcukoc. Biol. 57: 553–561; 1995.
Selective responses (actin polymerization, shape changes, locomotion, pinocytosis) to the PKC inhibitor Ro 31-8220 suggest that PKC discriminately regulates functions of human blood lymphocytes
Authors: Trachsel S , Keller H U
Published: January 2018

The results suggest that protein kinase C (PKC) plays a pivotal role in the control of F-actin levels, locomotion, pinocytosis, and cell shape in lymphocytes. The PKC inhibitor Ro 31-8220 elicits a high proportion of polarized (ED50 = 1,5 10-6 M) and locomoting cells and reduces the relative amount of F-actin (by 29% at 10-5 M) in initially resting cells. Phorbol myristate ace tate (PMA) counterbalances the polarizing effect of Ro 31-8220. This indicates that the spherical shape and the F-actin content of resting cells are maintained by con stitutive PKC activity. PMA-induced increases in fluid pinocytosis, F-actin content, and formation of nonpolar cells with surface protrusion are suppressed by Ro 31-8220 (IC50 = 2–4 10-7 M). Spherical cells and, at higher concentrations (ED50 = 13 10-6 M), polarized cells are formed instead. As a result, lymphocyte function switches from fluid pinocytosis to cell polarity and locomotion. The data indicate that PKC is instrumental in selectively switching lymphocyte function between resting state, locomotor activity, and fluid pinocytosis. Ro 31-8220 is extremely potent in stimulating lymphocyte polarity and locomotion (B and T cells). It acts faster and/or produces a higher proportion of polarized lymphocytes than other available agonists. It may thus be used as a tool in further experiments requiring locomoting lymphocytes.J. Leukoc. Biol. 57: 587–591; 1995.
Role of C-X-C chemokines as regulators of angiogenesis in lung cancer
Authors: Strieter Robert M , Polverini Peter J , Arenberg Douglas A , Walz Alfred , Opdenakker Ghislain , Van Damme Jo , Kunkel Steven L
Published: January 2018

Lung cancer is the leading cause of malignancy-related mortality in the U.S. and is predicted to increase over the remainder of this decade. Despite attempts to advance early diagnosis and use combination therapies, the clinical response of this cancer yields an overall 5-year survival rate of less than 15%. Clearly, new strategies for therapy are indicated. Although carcinogenesis is complex, tumor growth beyond 1–2 mm3 is dependent on angiogenesis. One of the potential mechanisms that allows for tumorigenesis is dysregulation of the balance of angiogenic and angiostatic factors that favors net neovascularization within the primary tumor. Numerous studies have investigated the role of a variety of molecules in the regulation of angiogenesis. Recently, interleukin-8 (IL-8), a member of the C-X-C chemokine family, has been found to be an angiogenic factor. In contrast, platelet factor 4 (PF4), another C-X-C chemokine, has been shown to have angiostatic properties. It is interesting that the major structural difference between IL-8 and PF4 is the presence of the NH2-terminal ELR (Glu-Leu-Arg) motif that precedes the first cysteine amino acid residue of IL-8 and is important in ligand/receptor interactions. We hypothesize that angiogenesis associated with tumorigenesis is dependent on members of the C-X-C chemokine family acting as either angiogenic or angiostatic factors. This paradigm predicts that the biological balance in the expression of these C-X-C chemokines dictates whether the neoplasm grows and develops metastatic potential or regresses. In this review we discuss our recent laboratory findings that support this contention and suggest that further elucidation of the biology of C-X-C chemokines in the context of neovascularization of nonsmall cell lung cancer will permit novel targeted therapy aimed specifically at attenuating tumor growth and metastasis. J. Leukoc. Biol. 57: 752–762; 1995.
Interleukin-3, granulocyte-macrophage colony-stimulating factor, and interleukin-5 transduce signals through two forms of STAT5
Authors: Mui Alice L-F , Wakao Hiroshi , Harada Nobuyuki , O’Farrell Anne-Marie , Miyajima Atsushi
Published: January 2018

Recently, JAK2 kinase was found to be one of the tyrosine kinases activated by interleukin-3 (IL-3) in target cells. JAK2 belongs to a family of kinases that act upstream of transcription factors called STATs. STATs exist in the cytoplasm as latent, transcriptionally inactive forms until, in response to extracellular signals, they become phosphorylated on tyrosine residues, translocate to the nucleus, and bind to specific DNA elements. Because IL-3 activates JAK2, we searched for the STAT(s) that might transduce IL-3 signals. Several lines of evidence suggest that IL-3 uses the murine homologue of STAT5, a factor originally purified from sheep. Unexpectedly, during isolation of the murine homologue, we found two highly related molecules that we have designated STAT5A and STAT5B. J. Leukoc. Biol. 57: 799–803; 1995.
Recombinant human IL-7 administration in mice affects colony-forming units-spleen and lymphoid precursor cell localization and accelerates engraftment of bone marrow transplants
Authors: Boerman Otto C , Gregorio Theresa A , Grzegorzewski Krzysztof J , Faltynek Connie R , Kenny James J , Wiltrout Robert H , Komschlies Kristin L
Published: January 2018

Murine reconstitution assays were used to investigate the effects of recombinant human interleukin-7 (rhIL-7) on myeloid and lymphoid precursors and on bone marrow engraftment. Reconstitution with bone marrow from rhIL-7-treated mice results in a 3.4-fold decrease in total colony-forming unit-spleen (CFU-S) activity (day 9) and an 18.1- and 11.9-fold decrease in its ability to generate thymocytes and splenic B lineage cells, respectively. In contrast, after reconstitution with splenocytes from rhIL-7-treated mice, CFU-S activity increased 23.6-fold (day 9) and the thymocyte and splenic B lineage cell regenerative capacity increased by 4.0- and 3.2-fold, respectively. In addition, CD43low+, B220low+ cells that contain pre-pro-B cells and pro-B cells were expanded two- to threefold and Igμ-, B220+, CD2- and Igμ-, B220+, CD2+ B lineage cells were expanded approximately 10-fold and 10- to 45-fold (depending on the tissue examined), respectively, after rhIL-7 treatment Administration of rhIL-7 to irradiated mice transplanted with bone marrow resulted in accelerated T cell and B cell reconstitution by up to 2–4 weeks. Thus, rhIL-7 administration affects the distribution of myeloid and lymphoid precursors. Moreover, rhIL-7 administration accelerates murine bone marrow cell engraftment and therefore may be useful in reducing the engraftment time in bone marrow transplant patients. J. Leukoc. Biol. 58: 151–158; 1995.
Enhanced expression of novel CD57+CD8+ LAK cells from cats infected with feline immunodeficiency virus
Authors: Zhao Y , Gebhard D , English R , Sellon R , Tompkins M , Tompkins W
Published: January 2018

As a model for lymphokine-activated killer (LAK) function in HIV infection, we studied LAK cells in cats infected with feline immunodeficiency virus (FIV), which causes an acquired immunodeficiency syndrome. Peripheral blood mononuclear cells cultured in concanavalin A and interleukin-2 developed LAK cytotoxicity against chronically FIV-infected CrFK cells and acutely infected CD4+ lymphocytes but not uninfected cells. LAK cells from FIV+ cats were more cytotoxic than LAK cells from uninfected cats. Enhanced FIV+ LAK cytotoxicity against feline leukemia virus–infected cells (FL74) suggested that the cytotoxicity was not antigen specific. Two-color fluorescence-activated cell sorter analysis and antibody depletion studies demonstrated that the majority of LAK cells and their progenitors were positive for both CD8 and CD57. The in vitro induction of dual positive CD8+CD57+ LAK cells was enhanced in FIV+ cats, as reported for HIV+ patients. These CD8+CD57+ LAK cells may play a role in maintaining the long asymptomatic stage of infection in FIV+ cats.
The effect of granulocyte-macrophage colony-stimulating factor on myeloid cells and its clinical applications
Authors: Hill Arnold D K , Naama Hassan A , Calvano Steve E , Daly John M
Published: January 2018

Granulocyte-macrophage colony-stimulating factor (GM-CSF) is a naturally occurring growth factor produced by several cell types in response to a variety of stimuli. GM-CSF has potent stimulatory effects on the growth and maturation of hematopoietic cells and has profound effects on mature circulating effector cells. Clinical applications of GM-CSF include ameliorating chemotherapy-induced neutropenia and enhancing hematopoietic recovery after bone marrow transplantation. This review evaluates the effect of GM-CSF on myeloid cells and its clinical applications.
Induction of apoptotic cell death in mouse lymphoma and human leukemia cell lines by a calcium-binding protein complex, calprotectin, derived from inflammatory peritoneal exudate cells
Authors: Yui Satoru , Mikami Masaaki , Yamazaki Masatoshi
Published: January 2018

We have previously shown that the calcium-binding protein complex, calprotectin, purified from rat inflammatory peritoneal cells exerts marked cytotoxic activity against rat, mouse, and human tumor cells. We studied here whether the cytotoxicity is caused by induction of apoptosis, using mouse EL-4 lymphoma and human MOLT-4 leukemia lines as targets. The rat calprotectin sample inhibited [3H]thymidine incorporation into these cells by partially 24 h and almost completely in 48 h of culture at concentrations of 100–200 μg/ml. Morphological changes, that is, loss of cell volume and nuclear condensation and/or fragmentation, appeared in both cell types cultured with calprotectin from 20 h, and such apoptotic cells subsequently increased in number to compose the great majority of the cells at 40 h. Cell death, measured by stainability with trypan blue, lagged behind the emergence of the apoptotic morphology by about 2 and 10 h in EL-4 and MOLT-4 cells, respectively. DNA fragmentation was observed in EL-4 cells cultured with calprotectin, whereas it was not observed in MOLT-4 cells, consistent with results of flow cytometry showing that loss of cell DNA content caused by the factor was greater in EL-4 cells. The data indicate that calprotectin induces the apoptosis of certain tumor cells but that the occurrence of DNA fragmentation is dependent on cell type. Finally, the apoptosis-inducing activity of the calprotectin sample was abrogated by the presence of 10 μM zinc, whereas it was not affected by 5 mM calcium or magnesium.
Effect of recombinant human macrophage-colony stimulating factor on marrow, splenic, and peripheral hematopoietic progenitor cells in mice
Authors: Yamauchi Takeshi , Yada Kouji , Umemura Akio , Asakura Eiji , Hanamura Takuji , Tanabe Toshizumi
Published: January 2018

The effects of human macrophage colony-stimulating factor (M-CSF) on marrow, splenic, and peripheral progenitor cells (CFU-M, CFU-GM, and CFU-G) were investigated in mice administered recombinant human M-CSF (8-4,000 μg/kg). Single injection of 4,000 μg/kg of M-CSF resulted in a decrease in the number of marrow progenitor cells (CFU-M, CFU-GM, and CFU-G) on day 2 followed by a gradual increase, returning to the original level on day 4 or 5. In contrast, each type of splenic progenitors tested for started to increase markedly on day 2, reaching a level 4- to 15-fold higher than that of the basal value on day 3 or 4. Peripheral CFU-M, CFU-GM, and CFU-G also increased on day 2. In addition, administration of 800 μg/kg of M-CSF in mice caused a decrease in marrow CFU-G, as well as an increase in splenic CFU-G. The present results indicate that treatments of mice with pharmacological concentrations of human M-CSF affect the number of progenitor cells not only of monocyte/macrophage lineage but also of granulocyte lineage. Also, the coincidence between decrease of marrow progenitor cells and increase of splenic and peripheral progenitor cells suggests that the progenitor cells are released from bone marrow to peripheral blood and reseeded to the spleen by the action of M-CSF.
Examination of the mononuclear phagocyte system in lupus-prone male BXSB mice
Authors: Vieten G , Grams B , Müller M , Hartung K , Emmendörffer A
Published: January 2018

During the course of lupus-like autoimmune disease male BXSB mice develop an increasing monocytosis in the peripheral blood. As we demonstrated previously, this monocytosis is parallelled by an expansion of a strain-specific high number of macrophage precursor cells (CFU-M) in the bone marrow of male mice. To test the hypothesis that the expanded mononuclear phagocyte system (MPS) may promote autoimmune disease in these mice the organ-associated macrophage system was examined. Our latest data show that an unusual expansion of CFU-M also appears in spleen and liver of male mice 2 weeks after birth. In addition to a morphological alteration of the organs during the course of the disease there is a change in number and distribution of organ-resident macrophages. Considering these results the possible contribution of the expanded MPS in promoting autoimmune disease is discussed.
Soluble extracellular antigen-specific T cell immunoproteins
Authors: Cone Robert E
Published: January 2018

Some T cells release proteins that bind specifically to antigens that have not been processed by antigen-presenting cells. These soluble immunoproteins induce or effect antigen-specific T cell functions in immunoregulation and/or hypersensitivity. After certain immunization regimens, T cell immunoproteins specific for the immunogen rise in serum, and therefore may be an antigen-specific, humoral manifestation of the activation of some T cells during an immune response. Although non-MHC (major histocompatibility complex)-associated antigen is bound, soluble antigen-specific T cell immunoproteins share variable and constant region epitopes and some amino acid sequence with the T cell receptor for antigen α or β chains, and their expression depends on T cell receptor structural genes. Herein, the properties of extracellular antigen-specific T cell immunoproteins are reviewed and it is suggested that these molecules are a soluble analogue of the T cell receptor for antigen and provide an amplifying element for some T cell functions.
Augmentations of glucose uptake and glucose transporter-1 in macrophages following thermal injury and sepsis in mice
Authors: Gamelli Richard L , Liu Hong , He Li-Ke , Hofmann Cecilia A
Published: January 2018

Glucose is the primary metabolic substrate of macrophages, which are critical components of the host response to injury and infection. We have carried out a series of studies to examine macrophage glucose uptake and the status of glucose transporter 1 (GLUTI) at both the mRNA and protein level. Peritoneal macrophages that were obtained from mice undergoing sham burned (S), 15%TBSA burn (B)±Pseudomonas aeruginosa burn infection (B + I) and lipopolysaccharide (LPS) or tumor necrosis factor-α (TNF-α) administration. [3H]deoxyglucose uptake was significantly increased (B, 157 ± 9%; B + I, 243 ± 19%; S + LPS, 231 ± 24%; S + TNF-α, 379 ± 18%; B + LPS, 230 ± 13%; and B + TNF, 305 ± 23%, P < 0.01 vs. sham). GLUTI mRNA and protein levels were increased as well (mRNA: B, 135 ± 13%; B + I, 250 ± 33%; S + LPS, 282 ± 29%; S + TNF-α, 193 ± 19%; B + LPS, 378 ± 20%; and B + TNF-α, 204 ± 16%; protein: B, 159 ± 27%; B + I, 181 ± 17%; S + LPS, 219 ± 26%; S + TNF-α, 343 ± 51%; B + LPS, 366 ± 41%; and B + TNF-α, 415 ± 44, P< 0.01 vs. sham). Macrophages co-cultured with LPS or TNF-α in vitro demonstrated a similar response pattern. Following burn injury and infection, macrophages augment their cellular glucose uptake, which is facilitated by an increased GLUT1 mRNA and protein levels. TNF-α elicited by LPS may mediate this enhanced carbohydrate metabolism at the point of glucose entry into the cell.
IFN-α-mediated suppression of low-affinity Fc receptors on Peyer’s patch lymphocytes and augmentation of soluble CD23: implications for IgE responses
Authors: Miller Hanan , Bluth Martin H , Chice Seto M , Durkin Helen G , Auci Dominick L
Published: January 2018

The ability of interleukin (IL)-6 or interferon-α (IFN-α) to regulate expression of low-affinity Fc receptor (CD23) and serum levels of CD23 was studied in benzylpenicilloyl-keyhole limpet hemocyanin-sensitized BALB/c mice at the peak of a haptenspecific immunoglobulin E (IgE) antibody-forming cell (AFC) response. These responses are analogous to those observed in human atopic disease. To induce peak IgE responses, mice were injected intraperitoneally with BPO-KLH (10 μg) in aluminum hydroxide gel (alum) on days 0, 21, and 42. On day 44, mice were injected subcutaneously with IL-6 (100-1000 U) or IFN-α (1000-10,000 U). On day 46, numbers of CD23+ lymphocytes in Peyer’s patches (PP), mesenteric lymph nodes (MLN), and spleen and levels of soluble CD23 in serum were determined (flow microfluorimetry and enzyme-linked immunosorbent assay, confirmed by competition assay). Data are expressed as percent total cells or as optical density at 490 nm. IFN-α treatment strongly suppressed (up to 100%) numbers of CD23+ cells exclusively in PP (i.e., numbers of CD23+ cells in MLN and spleen were unchanged) whereas serum levels of soluble CD23 were dramatically increased (60%). IL-6 treatment had no effect on either numbers of CD23+ lymphocytes or on serum levels of soluble CD23. The data suggest that the mechanism(s) by which IFN-α, but not IL-6, regulates IgE responses involves suppression of CD23 expression on lymphocytes in PPs and supports a central role for these organs in regulation of IgE responses in vivo.
Okadaic acid inhibits the signal responsible for activation of the NADPH-oxidase in neutrophils stimulated with serum-opsonized yeast
Authors: Harbecke Olle , Lundqvist Helen , Dahlgren Claes
Published: January 2018

The effects of the phosphatase inhibitor okadaic acid (OA) on human neutrophil phagocytic activity were investigated. The chemiluminescence response was found to be greatly reduced in OA-treated neutrophils during phagocytosis of serum opsonized yeast particles in comparison to control cells. However, the OA-treated neutrophils phagocytosed yeast particles to the same extent as control cells and the engulfment of the prey was accompanied by phagolysosomal formation in both OA- treated and nontreated cells. We thus found that the OA effect was selective in the sense that it inhibits the NADPH-oxidase activity in neutrophils phagocytosing yeast particles but not uptake of the prey or phagolysosomal formation. Based on the fact that the NADPH-oxidase activity induced by the chemoattractant formyl-methionyl-leucyl-phenylalanine was not reduced but elevated in OA-treated neutrophils, we conclude that the state of phosphorylation has no direct effect on the oxidase, but is of importance for the NADPH-oxidase activating signal(s) generated during phagocytosis of the yeast particles.
Membrane phospholipid asymmetry: host response to the externalization of phosphatidylserine
Authors: Bruckheimer Elizabeth M , Schroit Alan J
Published: January 2018

Membrane phospholipid asymmetry is an important regulator of cellular function and homeostasis. The activities of lipid transporters are contributing factors to the regulation of membrane lipid composition over the lifespan of the cell. Alterations in the activites of these proteins result in the movement of phosphatidylserine to the cell’s outer leaflet. This promotes several physiologic responses including initiation of the coagulation cascade and cell recognition by the reticuloendothelial system.
Enhanced expression and production of monocyte chemoattractant protein-1 in inflammatory bowel disease mucosa
Authors: Grimm Michael C , Elsbury Sue K O , Pavli Paul , Doe William F
Published: January 2018

Peripheral blood monocytes are recruited to the inflamed mucosa of inflammatory bowel disease but the specific chemotactic signals responsible for their attraction are not known. Monocyte chemoattractant protein-1 (MCP-1) is a chemokine with potent monocyte attracting and activating properties and the aim of this study was to examine its expression and production in inflammatory bowel disease. In situ hybridisation demonstrated mRNA for MCP-1 in macrophages, some of which had been recently recruited from the circulation as demonstrated by their co-expression of the monocyte marker CD14, as well as in smooth muscle and endothelial cells in inflamed mucosa. Immuno-histochemical studies showed a corresponding distribution of MCP-1 protein production by macrophages, smooth muscle, and endothelial cells. By contrast minimal MCP-1 mRNA expression and protein were found in histologically normal mucosa. Macrophages isolated from surgically resected inflammatory bowel disease colons and examined by Northern analysis expressed MCP-1 mRNA significantly more frequently (15/24 vs. 0/19, P< 0.0001) than macrophages from histologically normal mucosa from colon cancer resections. Blood monocytes stimulated by lipopolysaccharide and treated with hydrocortisone, 5-aminosalicylic acid, or cyclosporin A showed reduced MCP-1 expression and production in the presence of these agents. This study demonstrates increased expression of MCP-1 mRNA and protein and cells of origin of MCP-1 in inflamed intestinal mucosa. Together with the demonstrated influence of therapeutic agents on monocyte MCP-1 production the findings suggest a role for MCP-1 in monocyte attraction to the mucosal lesion of inflammatory bowel disease.
Colony stimulating factor-1 expression is developmentally regulated in the mouse
Authors: Roth Philip , Stanley E Richard
Published: January 2018

Colony stimulating factor-1 (CSF-1) regulates the survival, proliferation, and differentiation of mononuclear phagocytes. To determine whether CSF-1 plays a role in the perinatal development of these cells, CSF-1 protein and mRNA expression in tissues and serum from fetal/neonatal mice and their mothers was analyzed. As fetal/neonatal age increased, CSF-1 concentrations rose in liver, kidney, and lung, declined in brain and serum, and did not change in intestine and heart. Concurrently, fetal/neonatal CSF-1 concentrations were higher in liver, kidney, and serum and lower in lung, brain, intestine, and heart than maternal tissue/serum concentrations, which showed no correlations with gestational or post-partum stage. CSF-1 mRNA was detected in all tissues examined and its expression increased in lung and heart and decreased in brain with increasing fetal/neonatal age. The developmental regulation of mouse CSF-1 expression appears to be important for mononuclear phagocyte development during this period.
The inflammatory macrophage response to MCMV in mice with a retroviral immunodeficiency syndrome (MAIDS)
Authors: Allcock Richard J N , Peacock Craig D , Price Patricia
Published: January 2018

We have shown that normal C57BL/6J mice are moderately resistant to infection with murine cytomegalovirus (MCMV) and that this resistance is impaired by prior infection with LP-BM5 MuLV, which causes a disease (MAIDS) similar to early HIV-induced disease. This study investigates macrophage function in MAIDS+ mice challenged with MCMV. MAIDS reduces the influx of cells into the peritoneal cavity seen in normal C57BL/6J mice 6 days after MCMV infection. The infiltrates contained cells that resembled activated macrophages, as they took up colloidal gold, expressed the macrophage marker Mac-1, had high levels of acid phosphatase activity, and were lymphocytostatic when co-cultured with activated T cells. MAIDS+ mice had a higher percentage of cells able to take up colloidal gold and higher acid phosphatase activity per cell. The cells were also more lymphocytostatic and produced higher levels of interleukin-1 and tumor necrosis factor-α on days 4 and 6 after MCMV infection. Hence, MAIDS enhances baseline and induced macrophage activity, but depresses infiltration into the site of inflammation.
Lysis of leukemic cells by human macrophages: inhibition by 4-(2-aminoethyl)-benzenesulfonyl fluoride (AEBSF), a serine protease inhibitor
Authors: Nakabo Yukiharu , Pabst Michael J
Published: January 2018

Proteases are known to be involved in regulation of macrophage activation and killing. We examined the effect of a serine protease inhibitor, 4-(2-aminoethyl)-benzenesulfonyl fluoride (AEBSF), on lysis of leukemic cells by human macrophages. Monocytes, isolated by Histopaque gradients and centrifugal elutriation, were cultured for 5 days in RPMI-1640 medium with 5% AB serum, and then activated with interferon-γ (IFN-γ; 100 U/mL) and lipopolysaccharide (LPS) (5 ng/mL), with or without AEBSF, for 2 days. On day 7, macrophages were washed, fresh medium without AEBSF added, and target cells added for 2 days. Lytic activity against two leukemic cell lines (K562 and HL-60) was assessed by an 111indium-releasing assay. Macrophages treated with IFN-γ + LPS lysed K562 and HL-60 cells. AEBSF (50–150 μM) blocked the killing of these leukemic cells in a concentration-dependent manner. Other protease inhibitors were not effective. AEBSF was nontoxic at the concentrations used, and did not inhibit tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β) secretion from the macrophages. The lytic activity against leukemic cells was inhibited by anti-TNF-α antibody, but not by anti-IL-1β, nor by superoxide dismutase or catalase. However, the leukemic cells were resistant to being killed by recombinant TNF-α alone in the absence of macrophages, indicating that TNF-α was required for killing, but that other factors that were inhibited by AEBSF were also required. Serum-free culture supernatant of activated macrophages had significant cytotoxic activity against leukemic cells. This cytotoxic activity was not altered by addition of AEBSF to the culture supernatant, suggesting that AEBSF affected macrophage activation, rather than inhibiting cytotoxic proteases secreted by the macrophages, or affecting the target cells themselves. Thus, a protease, which is susceptible to AEBSF, might be involved in the activation of macrophages, and might regulate the secretion of antitumor effector molecules other than TNF-α.
Effects of hepatocellular mitogens on cytokine-induced nitric oxide synthesis in human hepatocytes
Authors: Liu Zhi-Ze , Cui Shijun , Billiar Timothy R , Dorko Kenneth , Halfter Willi , Geller David A , Michalopoulos George , Beger Hans-G , Albina Jorge , Nussler Andreas K
Published: January 2018

The synthesis of induced nitric oxide (NO) is regulated by several cytokines, including growth factors produced following hepatic injury and inflammation. However, little information is available on the role of growth factors in regulating the inducible NO synthase in human hepatocytes. The capacity of hepatocellular mitogens (HGF, EGF, and TGF-α) to regulate the inducible NO synthase (iNOS) was studied in human hepatocytes incubated with inflammatory cytokines and lipopolysaccharide (LPS). Furthermore, the effects of hepatic mitogens on NO-induced changes in DNA and protein synthesis was studied. It was found that NO-mediated decrease of protein and DNA synthesis were partially reversed by the mitogens. This was associated with a down-regulation in cytokine-mediated hepatocyte NO formation, iNOS mRNA expression, and NOS enzyme activity. Cytokine-induced NO formation or SNAP, an NO donor, added with cytokines increased hepatocyte chromatin condensation but no DNA fragmentation was observed. The increase in chromatin condensation was partially reversed by hepatic mitogens and corresponded with the inhibition of NO production. Thus, the hepatic mitogens, HGF, EGF, and TGF-α, all suppress iNOS expression and it is the suppression of iNOS that appears to be responsible for the mitogen-reduced preservation of DNA and protein synthesis and prevention of chromatin condensation.
T cell activation via the disialoganglioside GD3: analysis of signal transduction
Authors: Ortaldo John R , Mason Anna T , Longo Dan L , Beckwith Margaret , Creekmore Stephen P , McVicar Daniel W
Published: January 2018

The monoclonal antibody (mAb) R24 is a murine immunoglobulin G3 (IgG3) that reacts with the GD3 disialoganglioside present on melanoma cells as well as a subset of T cells. R24 mAb has induced antitumor responses both alone and in combination with interleukin-2 (IL-2) in clinical trials. We have reported T cell activation via GD3 as measured by the induction of tyrosine phosphorylation. In this study a more detailed analysis of signal transduction after ligation of GD3 was performed in an attempt to understand the mechanism of in vivo therapeutic benefits observed. Analysis of subsequent events indicated that GD3 engagement resulted in phospholipase Cγ phosphorylation and calcium flux. When ras-associated events were examined, GD3 signaling resulted in ras activation as determined by GDP/GTP conversion as well as dose-and time-dependent IP3 activation. In addition, the majority of the IPS activation by GD3 was inhibited by herbimycin A pretreatment. Elucidation of the nature and potential role of this moiety in GD3 signal transduction should be useful. Collectively, these data suggest a novel mechanism of T cell activation via a single, non-protein, surface moiety. This novel form of T cell-mediated activation may permit the delivery and local activation of effector cells at the tumor resulting in site-specific activation of the immune system.
Secretory phospholipase A2 activity is elevated in bronchoalveolar lavage fluid after ovalbumin sensitization of guinea pigs
Authors: Sane Aneysa C , Mendenhall Tiffany , Bass David A
Published: January 2018

Arachidonic acid (AA), the precursor of eicosanoids, is released from the sn-2 position of phospholipids by both secretory (8PLA2) and cytosolic phospholipase A2 (CPLA2). Eicosanoids have been shown to contribute to bronchospasm in asthma. We measured the enzymatic activity of 8PLA2 and CPLA2 in the bronchoalveolar lavage fluid and cells, respectively, in male Hartley guinea pigs sensitized with ovalbumin. sPLA2 activity was also measured from alveolar macrophages (AM) in culture from unsensitized and sensitized animals. There was an increase in 8PLA2 activity and AA content in the lavage fluid following sensitization (18.73 ± 1.33 to 25.74 ± 3.22% hydrolysis and 17.97 ± 12.39 to 44.76 ± 13.37 pmol AA/mL BAL, mean ± SD), which remained elevated but without further increase 4 or 24 h after antigen challenge. AM from unsensitized and sensitized-unchallenged animals did not secrete 8PLA2 activity in culture for 3 h and therefore do not appear to be the cell source of the sPLA2 activity present in the alveolar lavage fluid following OA sensitization. In contrast to the increase in 8PLA2 in lung lavage fluid, Western blotting for CPLA2 from lung lavage cells showed no increase 4 or 24 h after antigen challenge compared with sensitization alone. CPLA2 enzymatic activity of the cytosol fraction of lung lavage cells showed no changes with antigen sensitization or challenge. In summary, intraperitoneal sensitization with ovalbumin in male Hartley guinea pigs caused an increase in both sPLA2 and AA in bronchoalveolar lavage fluid without a need for antigen challenge. The increased 8PLA2 enzymatic activity following sensitization may be responsible for the elevation of AA in the bronchoalveolar lavage fluid observed after antigen sensitization.
Cathepsin G binds to human lymphocytes
Authors: Yamazaki Tomomi , Aoki Yosuke
Published: January 2018

Cathepsin G is a serine protease located in the azurophil granules of neutrophils. We have shown previously that cathepsin G stimulates human lymphocytes. In this study, we demonstrate that cathepsin G exhibits specific, saturable and reversible binding to lymphocytes: B cells, CD4+ T cells, CD8+ T cells, and natural killer (NK) cells. Phenylmethylsulfonyl fluoride (PMSF) -inhibited cathepsin G also bound to lymphocytes, although both the number of binding sites and the affinity were less than those of native cathepsin G. The binding of cathepsin G to lymphocytes showed cooperativity, but that of PMSF-inhibited cathepsin G did not. PMSF-inhibited cathepsin G was able to partially displace bound cathepsin G. These results suggest that molecules on the lymphocyte surface that bind cathepsin G recognize not only the active site of cathepsin G but also other sites of this molecule, but the active site has an important function in this binding because stimulation of lymphocytes requires the binding of proteolytically active cathepsin G.
Expression of the human NRAMP1 gene in professional primary phagocytes: studies in blood cells and in HL-60 promyelocytic leukemia
Authors: Cellier Mathieu , Shustik Chaim , Dalton William , Rich Elizabeth , Hu Jinxin , Malo Danielle , Schurr Erwin , Gros Philippe
Published: January 2018

In the mouse, mutations at the natural resistance-associated macrophage protein 1 (Nrampl) gene abrogate resistance to infection with antigenically unrelated intracellular parasites such as Mycobacterium, Salmonella, and Leishmania. Nrampl expression is restricted to reticuloendothelial organs and peripheral blood leukocytes, where the protein may function as a membrane transporter of an as yet to be identified substrate. To identify the human blood cell type(s) expressing NRAMPl mRNA and determine how Nrampl expression is regulated in these cells, we have examined separated populations of peripheral blood leukocytes and in vitro cell lines. We observed that polymorphonuclear leukocytes (PMN) are the major site of NRAMP1 expression, followed to a lesser degree by monocytes (MN). Migration of MN to tissues (alveolar macrophages) or maturation in vitro (long-term culture) was associated with a higher level of NRAMP1 expression compared with blood MN. Northern analyses of RNA from model cultured cells showed absence of NRAMP1 expression in transformed cell lines from either erythroid or lymphoid T or B lineages as well as progenitors of the monocyte/macrophage pathway (KG1, U937, THP1), and the HL-60 promyelocytic leukemia. Induction of differentiation of HL-60 cells toward either the monocyte/ macrophage (vitamin D3, phorbol ester) or the granulocyte pathways (DMF, DMSO), as measured by induction of IL8-Rb, c-FMS, and CD14 marker gene expression, was concomitant with a strong induction of NRAMP1 expression. These results suggest that NRAMP1 expression is specific to the myeloid lineage and is acquired during the maturation of PMN and MN. The possibility that NRAMP1 may be a component of the phagosomal/endosomal apparatus common to PMN and MN is discussed.