bluuebunny/crossref_metadata_2025 huggingface dataset:
H1° histone and differentiation of dendritic cells. A molecular target for tumor-derived factors
Authors: Gabrilovich Dmitry I , Cheng Pingyan , Fan Yuhong , Yu Bin , Nikitina Ekaterina , Sirotkin Allen , Shurin Michael , Oyama Tsunehiro , Adachi Yasushi , Nadaf Sorena , Carbone David P , Skoultchi Arthur I
Published: September 2022

Dendritic cells (DC) play a central role in antitumor immune responses. Abnormal differentiation of DC and their inability to stimulate T cells are important factors in tumor escape from immune-system control. However, the mechanisms of this process remain elusive. Here, we have described one possible molecular mechanism that involves replacement linker histone H1°. A close association between expression of H1° and DC differentiation in vitro has been found. DC production in H1°-deficient mice was decreased significantly, whereas generation and function of macrophages, granulocytes, and lymphocytes appear to be normal. However, these mice had a significantly reduced response to vaccination with antigens. Tumor-derived factors considerably reduced h1° expression in hematopoietic progenitor cells. We have demonstrated that transcription factor NF-κB is involved actively in regulation of h1°. Thus, H1° histone may be an important factor in normal DC differentiation. Tumor-derived factors may inhibit DC differentiation by affecting H1° expression.
Cytokine responses of bovine dendritic cells and T cells following exposure to live or inactivated bovine respiratory syncytial virus
Authors: Werling Dirk , Collins Robert A , Taylor Geraldine , Howard Chris J
Published: September 2022

We compared the effects of live or inactivated bovine respiratory syncytial virus (BRSV) on cytokine production by bovine monocyte-derived dendritic cells (MoDC). We also investigated the response of resting memory CD4+ T cells to MoDC exposed to both viral preparations. Although BRSV did not appear to replicate in MoDC or to affect expression of major histocompatibility complex (MHC) class I, MHC class II, or CD80/86, a higher percentage of cells exposed to live virus appeared to undergo apoptosis/necrosis. To investigate how the interaction of BRSV with MoDC affects the immune response, a multiplex, real-time, polymerase chain reaction was established to analyze transcription of bovine cytokines. Exposure of MoDC to live BRSV induced more interleukin (IL)-10 mRNA and markedly less IL-12p40 and IL-15 mRNA than did heat-inactivated virus. To determine whether these differences might influence the T cell response, CD4+ memory T cells primed in vivo were restimulated in vitro by MoDC pulsed with heat-inactivated or live BRSV. Stimulation of CD4+ T cells induced similar levels of IL-2-and IL-4-like activity and interferon-γ. These observations suggest that while IL-10, produced by MoDC as a result of exposure to live BRSV, may affect IL-12 and IL-15 synthesis by MoDC, it does not appear to affect the cytokine response of BRSV-specific memory CD4+ T cells. It is possible, however, that differences in the pattern of cytokines produced by MoDC exposed to live or inactivated virus may influence the development of the primary CD4+ T cell response in vivo.
Human dendritic cell mediated cytotoxicity against breast carcinoma cells in vitro
Authors: Manna Partha P , Mohanakumar T
Published: September 2022

Dendritic cells (DC) are an important subset of antigen-presenting cells characterized by their potent capacity to activate immunologically naïve T cells. However, their role in effector function in tumor resistance is less well characterized. We report here that activated human peripheral blood DC acquire a potent antitumor effect against breast cancer cell lines in vitro, leading to growth inhibition and apoptosis of the tumor cell. The antitumor effect of DC was augmented by proinflammatory stimuli induced by lipopolysaccharide (LPS) treatment. Tumor necrosis factor α (TNF-α) produced after DC activation was responsible for the antitumor activity of DC. Interferon-γ, interleukin-15, or LPS treatment of DC markedly augmented the effector function of DC against most of the breast cells, indicating heterogeneity of the tumor and its susceptibility to cytokine-mediated damage. Treatment of LPS-activated DC or cell-free supernatant with anti-human TNF-α significantly reduces the antitumor effect against the tumor cells tested. These results suggest that in addition to their predominant role as immune regulatory cells, DC could serve as innate effector cells in tumor immunity.
Nitric oxide reduces bacterial superantigen-immune cell activation and consequent epithelial abnormalities
Authors: Rachlis Alisa , Watson James L , Lu Jun , McKay Derek M
Published: September 2022

Inhibition of the inducible form of nitric oxide (NO) synthase prolonged the murine enteropathy evoked by the bacterial superantigen, Staphylococcus aureus enterotoxin B (SEB). We examined the ability of NO to alleviate SEB-induced epithelial dysfunction and immune cell activation. Human peripheral blood mononuclear cells (PBMC) were activated by SEB for 24 h ± the NO donors, S-nitroso-N-acetylpenicillamine and spermine-NONOate. The conditioned medium (CM) was collected and applied to T84 epithelial monolayers, and permeability [i.e., transepithelial resistance (TER)] and stimulated ion transport (i.e., short-circuit current responses to carbachol and forskolin) were assessed 24 h later. Exposure to CM led to an ∼40% drop in TER and hyporesponsiveness to both secretagogues. CM made in the presence of NO donors (10−4 M) had no significant effect on epithelial barrier or ion transport parameters. NO donors alone had no effect on naive epithelia, and addition of the NO donors to previously made CM did not affect the ability of this CM to alter epithelial function. Moreover, the NO donors dose-dependently reduced SEB-evoked PBMC proliferation and cytokine production (i.e., interferon-γ, tumor necrosis factor α) but did not affect viability. These findings suggest a beneficial role for NO in inflammation by reducing immune cell activation and thus ameliorating consequent physiological abnormalities, in this instance, perturbed epithelial permeability and active ion transport.
Physiological levels of interleukin-18 stimulate multiple neutrophil functions through p38 MAP kinase activation
Authors: Wyman Travis H , Dinarello Charles A , Banerjee Anirban , Gamboni-Robertson Fabia , Hiester Andrew A , England Kelly M , Kelher Marguerite , Silliman Christopher C
Published: September 2022

Patients with sepsis and acute lung injury have increased interleukin (IL)-18 levels systemically. We hypothesize that IL-18 stimulates neutrophils (PMNs) at physiologic concentrations. IL-18 primed the oxidase at 15 min (10–100 ng/ml), 30 min (0.1–100 ng/ml), and 60 min (100 ng/ml; P<0.05) and caused translocation of p47phox to the membrane similar to lipopolysaccharides. CD11b surface expression was increased by IL-18 in a time- and concentration-dependent manner. IL-18 caused up-regulation of the formyl-Met-Leu-Phe receptor, changes in PMN size, and elastase release. Investigation of signaling demonstrated IL-18-mediated activation of p38 mitogen-activated protein (MAP) kinase in a concentration (0.1–100 ng/ml)-, time (5–15 min)-, and Ca2+-dependent manner. IL-18 directly increased cytosolic Ca2+ concentration. IL-18 activation of PMNs was blocked by inhibition of p38 MAP kinase activity (SB203580) or by inhibition of p38 MAP kinase activation by chelation of cytosolic Ca2+. We conclude that IL-18, at physiologic concentrations, is an effective PMN priming agent that requires p38 MAP kinase activity.
Orphan nuclear receptors in T lymphocyte development
Authors: He You-Wen
Published: September 2022

Lymphocyte development is initiated from hematopoietic stem cells and can be divided into multiple phenotypically distinct stages. Transcription factors play important roles in programming the developmental process of lymphocytes. Recent studies have identified key roles of several orphan nuclear receptors in T lymphocyte development. The orphan nuclear receptor RORγ has been shown to promote thymocyte survival by activating the expression of antiapoptotic protein Bcl-xL. RORγ is also required for the development of lymph nodes and Peyer's patches. The orphan receptors Nur77 and Nor1 are involved in TCR-mediated cell death and thymocyte-negative selection. These studies provide novel insights into the molecular mechanisms of T lymphocyte development.
Interleukin-10 inhibits proinflammatory activation of endothelium in response toBorrelia burgdorferior lipopolysaccharide but not interleukin-1β or tumor necrosis factor α
Authors: Lisinski Tracy J , Furie Martha B
Published: September 2022

Interleukin (IL)-10 is generally regarded as an anti-inflammatory cytokine, since it acts on a variety of cell types to suppress production of proinflammatory mediators. In inflammation, endothelial cells (EC) play a crucial role in recruiting leukocytes to sites of injury or infection. In this study, the actions of IL-10 on human umbilical vein EC were investigated. IL-10 reduced migration of monocytes and T lymphocytes across endothelium stimulated by lipopolysaccharide and decreased endothelial production of chemokines in response to lipopolysaccharide and Borrelia burgdorferi, the agent of Lyme disease. However, IL-10 did not affect these responses when EC were activated by the host proinflammatory cytokines IL-lβ or tumor necrosis factor α. Moreover, IL-10 did not prevent up-regulation of the adhesion molecules E-selectin and intercellular adhesion molecule-1 by EC exposed to any of these activating agents. IL-10 therefore inhibits proinflammatory activation of EC in a manner that is selective with respect to stimulus and effector response.
Human pregnancy-specific glycoprotein 1a (PSG1a) induces alternative activation in human and mouse monocytes and suppresses the accessory cell-dependent T cell proliferation
Authors: Motrán Claudia Cristina , Díaz Fernando López , Gruppi Adriana , Slavin Daniela , Chatton Bruno , Bocco José Luis
Published: September 2022

It has been proposed that pregnancy-specific factors induce the suppression of a specific arm of the maternal response accompanied by activation of the nonspecific, innate immune system. The aim of this study was to determine whether pregnancy-specific glycoprotein 1a (PSG1a), the major variant of PSG polypeptides, is able to modulate the monocyte/macrophage (Mo) metabolism to rgulate T cell activation and proliferation. Using the recombinant form of this glycoprotein (rec-PSG1a), expressed in mammalian cells with a vaccinia-based expression vector, we have demonstrated that human PSG1a induces arginase activity in peripheral blood human Mo and human and murine Mo cell lines. In addition, rec-PSG1a is able to induce alternative activation because it up-regulates the arginase activity and inhibits the nitric oxide production in Mo activated by lipopolysaccharides. We also observed that rec-PSG1a is an important accessory cells-dependent T cell suppressor factor that causes partial growth arrest at the S/G2/M phase of the cell cycle. Additionally, an impaired T cell proliferative response induced by mitogens and specific antigen was observed in BALB/c mice upon in vivo expression of PSG1a. Our results suggest that PSG1a function contributes to the immunomodulation during pregnancy, having opposite effects on maternal innate and adaptative systems.
In vitro and in vivo activities of OX40 (CD134)-IgG fusion protein isoforms with different levels of immune-effector functions
Authors: Taylor Liz , Bachler Marcus , Duncan Imogen , Keen Simon , Fallon Rosie , Mair Catherine , McDonald Thomas T , Schwarz Herbert
Published: September 2022

Recombinant fusion proteins consisting of the extracellular domain of immunoregulatory proteins and the constant domain of immunoglobulin G (IgG) are a novel class of human therapeutics. IgG isofors exert different levels of immune effector functions, such as complement lysis and antibody-dependent cell cytotoxicity (ADCC). Several OX40-Ig fusion proteins were generated and compared in their potency to inhibit immune reactions. OX40-IgG fusion proteins act as decoys and inhibit T cell costimulation and extravasation induced by OX40 ligand-expressing antigen-presenting cells (APC) and vascular endothelial cells, respectively. In addition, OX40-IgG1 protein induces ADCC and complement lysis in OX40 ligand-expressing cells. Replacement of the IgG1 by the IgG4 domain (OX40-IgG4) eliminated complement lysis and reduced ADCC by half. Mutation of Leu235 to Glu in IgG4 eliminated the remaining ADCC activity and generated a protein devoid of immune effector functions (OX40-IgG4mut). In vitro, OX40-IgG1 was more potent in inhibiting proliferation and cytokine release by peripheral blood mononuclear cells than OX40-IgG4mut, as OX40-IgG1 induced cell death in APC. However, both proteins reduced T cell-mediated colitis in mice to the same extent, indicating that in vivo neutralization of OX40L is sufficient. This study also demonstrates that effector functions of antibodies are retained and can be rationally designed in receptor-IgG fusion proteins.
RAW 264.7 macrophages induce apoptosis selectively in transformed fibroblasts: intercellular signaling based on reactive oxygen and nitrogen species
Authors: Heigold Stefanie , Bauer Georg
Published: September 2022

The rationale for this study was to determine whether macrophages induce apoptosis selectively in transformed compared with nontransformed fibroblasts and to elucidate the underlying intercellular signaling chemistry. Murine fibroblasts transformed by oncogene expression (ras, src) or methylcholanthrene treatment were sensitive for apoptosis induction by RAW 264.7 macrophages, whereas parental cells and revertants were insensitive. Moreover, RAW 264.7 macrophages induced apoptosis in normal rat kidney (NRK) fibroblasts transiently transformed by epidermal growth factor/transforming growth factor-β. Sensitivity for intercellular apoptosis induction was based on target cell-derived superoxide anions and effector cell-derived peroxidase and nitric oxide (NO). Superoxide anions dismutate to hydrogen peroxide, which is converted to HOCl by the peroxidase. The interaction of HOCl with superoxide anions then generates hydroxyl radicals. In parallel, NO interacts with superoxide anions and generates apoptosis-inducing peroxynitrite. Signaling by reactive oxygen and nitrogen species seems to represent a hitherto unrecognized signaling principle for the selective elimination of potential tumor cells by macrophages.
Potential role of the formyl peptide receptor-like 1 (FPRL1) in inflammatory aspects of Alzheimer's disease
Authors: Cui Youhong , Le Yingying , Yazawa Hiroshi , Gong Wanghua , Wang Ji Ming
Published: September 2022

Alzheimer's disease (AD) is a progressive, neurodegenerative disease characterized by the presence of multiple senile plaques in the brain tissue, which are also associated with considerable inflammatory infiltrates. Although the precise mechanisms of the pathogenesis of AD remain to be determined, the overproduction and precipitation of a 42 amino acid form of β amyloid (Aβ42) in plaques have implicated Aβ in neurodegeneration and proinflammatory responses seen in the AD brain. Our recent studies revealed that the activation of formyl peptide receptor-like 1 (FPRL1), a seven-transmembrane, G-protein-coupled receptor, by Aβ42 may be responsible for accumulation and activation of mononuclear phagocytes (monocytes and microglia). We further found that upon binding FPRL1, Aβ42 was rapidly internalized into the cytoplasmic compartment in the form of Aβ42/FPRL1 complexes. Persistent exposure of FPRL1-expressing cells to Aβ42 resulted in intracellular retention of Aβ42/FPRL1 complexes and the formation of Congo-red-positive fibrils in mononuclear phagocytes. Our observations suggest that FPRL1 may not only mediate the proinflammatory activity of Aβ42 but also actively participate in Aβ42 uptake and the resultant fibrillar formation. Therefore, FPRL1 may constitute an additional molecular target for the development of therapeutic agents for AD.
Hepatic natural killer cells exclusively kill splenic/blood natural killer-resistant tumor cells by the perforin/granzyme pathway
Authors: Vermijlen David , Luo Dianzhong , Froelich Christopher J , Medema Jan Paul , Kummer Jean Alain , Willems Erik , Braet Filip , Wisse Eddie
Published: September 2022

Hepatic natural killer (NK) cells are located in the liver sinusoids adherent to the endothelium. Human and rat hepatic NK cells induce cytolysis in tumor cells that are resistant to splenic or blood NK cells. To investigate the mechanism of cell death, we examined the capacity of isolated, pure (90%) rat hepatic NK cells to kill the splenic/blood NK-resistant mastocytoma cell line P815. Cell death was observed and quantified by fluorescence and transmission electron microscopy, DNA fragmentation, and 51Cr release. RNA and protein expression were determined by real time reverse transcription-polymerase chain reaction and Western blotting. Compared with splenic NK cells, hepatic NK cells expressed higher levels of perforin and granzyme B and readily induced apoptosis in P815 cells. Although P815 cells succumbed to recombinant Fas ligand (FasL) or isolated perforin/granzyme B, hepatic NK cells used only the granule pathway to kill this target. In addition, hepatic NK cells and sinusoidal endothelial cells strongly expressed the granzyme B inhibitor, protease inhibitor 9 (PI-9)/serine PI-6 (SPI-6), and P815 cells and hepatocytes were negative. Transfection of target cells with this inhibitor resulted in complete resistance to hepatic NK cell-induced apoptosis. In conclusion, hepatic NK cells kill splenic/blood NK-resistant/FasL-sensitive tumor cells exclusively by the perforin/granzyme pathway. Serine protease inhibitor PI-9/SPI-6 expression in liver sinusoidal endothelial cells may protect the liver microenvironment from this highly active perforin/granzyme pathway used to kill metastasizing cancer cells.
Calcium spikes in activated macrophages during Fcγ receptor-mediated phagocytosis
Authors: Myers Jesse T , Swanson Joel A
Published: September 2022

Rises in intracellular-free calcium ([Ca2+]i) have been variously associated with Fcγ receptor (FcR)-mediated phagocytosis in macrophages. We show here that activation of murine bone marrow-derived macrophages increases calcium spiking after FcR ligation. Ratiometric fluorescence microscopy was used to measure [Ca2+]i during phagocytosis of immunoglobulin G (IgG)-opsonized erythrocytes. Whereas 13% of nonactivated macrophages increased [Ca2+]i in the form of one or more spikes, 56% of those activated with lipopolysaccharides (LPS; 18 h at 100 ng/ml) and interferon-γ (IFN-γ; 100 U/ml) and 73% of macrophages activated with LPS, IFN-γ, interleukin (IL)-6 (5 ng/ml), and anti-IL-10 IgG (5 μg/ml) spiked calcium during phagocytosis. Calcium spikes were inhibited by thapsigargin (Tg), indicating that they originated from endoplasmic reticulum. The fact that activated macrophages showed a more dramatic response suggested that calcium spikes during phagocytosis mediate or regulate biochemical mechanisms for microbicidal activities. However, lowering [Ca2+]i with ethyleneglycol-bis(β-aminoethylether)-N,N′-tetraacetic acid or inhibiting calcium spikes with Tg did not inhibit phagosome-lysosome fusion or the generation of reactive oxygen or nitrogen species. Thus, the increased calcium spiking in activated macrophages was not directly associated with the mechanism of phagocytosis or the increased antimicrobial activities of activated macrophages.
Stimulation of neutrophil apoptosis by immobilized IgA
Authors: Schettini Jorge , Salamone Gabriela , Trevani Analía , Raiden Silvina , Gamberale Romina , Vermeulen Mónica , Giordano Mirta , Geffner Jorge R
Published: September 2022

In the current study, we analyzed whether immunoglobulin A (IgA) is able to modulate neutrophil apoptosis. We found that culture of neutrophils on immobilized plasma IgA (iIgAp) or secretory IgA (iIgAs) induced a marked increase in apoptotic rates. By contrast, soluble IgAp, IgAs, or aggregated IgAp exerted no effect. Promotion of apoptosis by iIgA was almost completely prevented by blocking antibodies directed to CD18 or CD11b and was shown to be dependent on the activation of the respiratory burst as suggested by the ability of catalase to prevent apoptosis stimulation; the effect of azide, an heme enzyme inhibitor that significantly increased promotion of apoptosis by iIgA; and the inability of iIgA to stimulate apoptosis of neutrophils isolated from chronic granulomatous disease patients. Stimulation of neutrophil apoptosis by IgA might contribute to the control of inflammatory processes in certain autoimmune diseases such as IgA nephropathy in which tissue deposits of IgA or IgA containing immune complexes are found.
MUC1 epithelial mucin (CD227) is expressed by activated dendritic cells
Authors: Wykes M , MacDonald K P A , Tran M , Quin R J , Xing P X , Gendler S J , Hart D N J , McGuckin M A
Published: September 2022

The MUC1 mucin (CD227) is a cell surface mucin originally thought to be restricted to epithelial tissues. We report that CD227 is expressed on human blood dendritic cells (DC) and monocyte-derived DC following in vitro activation. Freshly isolated murine splenic DC had very low levels of CD227; however, all DC expressed CD227 following in vitro culture. In the mouse spleen, CD227 was seen on clusters within the red pulp and surrounding the marginal zone in the white pulp. Additionally, we confirm CD227 expression by activated human T cells and show for the first time that the CD227 cytoplasmic domain is tyrosine-phosphorylated in activated T cells and DC and is associated with other phosphoproteins, indicating a role in signaling. The function of CD227 on DC and T cells requires further elucidation.
Increased PSGL-1 expression on granulocytes from allergic-asthmatic subjects results in enhanced leukocyte recruitment under flow conditions
Authors: Dang Bao , Wiehler Shahina , Patel Kamala D
Published: September 2022

Allergic asthma is increasing in incidence and severity in many industrial countries. Leukocyte recruitment into the airways of affected individuals contributes to the severity of the disease. In this study, whole blood from normal, allergic, asthmatic, or allergic-asthmatic subjects was perfused over immobilized adhesion molecules using an in vitro flow chamber system to determine if there were differences in leukocyte recruitment in these patient populations. Leukocytes from allergic-asthmatic subjects showed a threefold increase in recruitment on P-selectin as compared with normal controls. In both patient populations, the accumulated cells were exclusively neutrophils and eosinophils. Increased granulocyte recruitment was specific for P-selectin, as neither purified E-selectin nor vascular cell adhesion molecule-1 (VCAM-1) supported enhanced leukocyte recruitment from allergic-asthmatics. Leukocyte accumulation on P-selectin was completely blocked by an anti-P-selectin or anti-P-selectin glycoprotein ligand-1 (PSGL-1) monoclonal antibody. Flow cytometry revealed that neutrophils and eosinophils from allergic-asthmatic subjects had increased expression of PSGL-1, whereas expression of another adhesion molecule, L-selectin, was unchanged. PSGL-1 expression on peripheral blood mononuclear cells of allergic-asthmatic patients was unaffected. The increased PSGL-1 expression on granulocytes from allergic-asthmatic patients also led to enhanced leukocyte recruitment on interleukin-4-stimulated human umbilical vein endothelial cells, which express P-selectin and VCAM-1. Thus, increased PSGL-1 expression on granulocytes from allergic-asthmatic subjects resulted in increased leukocyte recruitment on P-selectin under flow conditions.
Endotoxin induces rapid metalloproteinase-mediated shedding followed by up-regulation of the monocyte hemoglobin scavenger receptor CD163
Authors: Hintz Katharine A , Rassias Athos J , Wardwell Kathleen , Moss Marcia L , Morganelli Peter M , Pioli Patricia A , Givan Alice L , Wallace Paul K , Yeager Mark P , Guyre Paul M
Published: September 2022

CD163, a monocyte and macrophage-specific surface glycoprotein, which is increased by interleukin-10 and glucocorticoids, is a scavenger receptor for hemoglobin/haptoglobin complexes. We report a rapid and highly reproducible rise in soluble CD163 in the plasma of human volunteers given intravenous lipopolysaccharide (LPS). We also show that LPS induces shedding of CD163 from the surface of isolated monocytes, identifying shedding from monocytes and macrophages as a likely mechanism for the endotoxemia-associated rise in plasma CD163 in vivo. Studies using the inhibitor TAPI-0 indicate that a metalloproteinase is responsible for LPS-mediated shedding of CD163. Finally, we demonstrate a marked increase in surface CD163 expression on circulating monocytes 24 h following experimental endotoxemia. These findings show that CD163 is rapidly mobilized in response to bacterial endotoxin. As hemoglobin can bind LPS and enhance its toxicity, it will be important to determine how cell surface and soluble CD163 influence inflammatory processes during sepsis.
IFN-γ and IL-12 differentially regulate CC-chemokine secretion and CCR5 expression in human T lymphocytes
Authors: Losana Giuliana , Bovolenta Chiara , Rigamonti Laura , Borghi Igor , Altare Frederic , Jouanguy Emmanuelle , Forni Guido , Casanova Jean-Laurent , Sherry Barbara , Mengozzi Manuela , Trinchieri Giorgio , Poli Guido , Gerosa Franca , Novelli Francesco
Published: September 2022

Interleukin (IL)-12, especially in the presence of neutralizing anti-IL-4 monoclonal antibodies, primed CD45RO− T clones for high CCL3/macrophage-inflammatory protein-1α (MIP-1α) and CCL4/MIP-1β levels. In CD4+ and CD8+ clones from two patients deficient for IL-12Rβ1 (IL-12Rβ1−/−), production of CCL3/MIP-1α and CCL4/MIP-1β was defective. CD4+ clones from two patients deficient for interferon-γ (IFN-γ) R1 (IFN-γR1−/−) produced somewhat decreased CCL4/MIP-1β levels. IL-12 failed to prime CD4+ or CD8+ healthy clones for high CCL5/regulated on activation, normal T expressed and secreted (RANTES) production, although its secretion was impaired in CD4+ clones from IL-12Rβ1−/− and IFN-γR1−/− patients. CCR5 surface expression was up-regulated in resting peripheral blood mononuclear cells and CD4+ clones from both kinds of patients, rendering them more susceptible to CCR5-dependent (R5) HIV-1 infection. Neutralization of IFN-γ increased CCR5 expression and decreased CC-chemokine secretion by CD4+ clones from healthy and IL-12Rβ1−/− individuals, suggesting an IFN-γ-dependent control of CCR5 expression. These data provide the first documented analysis of chemokine secretion and chemokine receptor expression on T cells from IL-12 and IFN-γ receptor-deficient patients and dissect the role of IL-12 and IFN-γ on inducing inflammatory chemokine secretion and down-regulating CCR5 expression in human T cells.
Phosphorylation-dependent interaction of osteopontin with its receptors regulates macrophage migration and activation
Authors: Weber Georg F , Zawaideh Samer , Hikita Sherry , Kumar Vikram A , Cantor Harvey , Ashkar Samy
Published: September 2022

Neutrophil-independent macrophage responses are a prominent part of delayed-type immune and healing processes and depend on T cell-secreted cytokines. An important mediator in this setting is the phosphoprotein osteopontin, whose secretion by activated T cells confers resistance to infection by several intracellular pathogens through recruitment and activation of macrophages. Here, we analyze the structural basis of this activity following cleavage of the phosphoprotein by thrombin into two fragments. An interaction between the C-terminal domain of osteopontin and the receptor CD44 induces macrophage chemotaxis, and engagement of β3-integrin receptors by a nonoverlapping N-terminal osteopontin domain induces cell spreading and subsequent activation. Serine phosphorylation of the osteopontin molecule on specific sites is required for functional interaction with integrin but not CD44 receptors. Thus, in addition to regulation of intracellular enzymes and substrates, phosphorylation also regulates the biological activity of secreted cytokines. These data, taken as a whole, indicate that the activities of distinct osteopontin domains are required to coordinate macrophage migration and activation and may bear on incompletely understood mechanisms of delayed-type hypersensitivity, wound healing, and granulomatous disease.
Endothelial Rho and Rho kinase regulate neutrophil migration via endothelial myosin light chain phosphorylation
Authors: Saito Hajime , Minamiya Yoshihiro , Saito Satoshi , Ogawa Jun-ichi
Published: September 2022

The transendothelial migration of neutrophils is a critical step in acute inflammation, which we previously showed to be regulated by endothelial myosin light chain (MLC) kinase. Recent studies suggest that Rho and Rho kinase are also key mediators of MLC phosphorylation, but their roles in neutrophil migration have not been investigated. In the present study, a transwell chamber migration assay system incorporating endothelial monolayer was used to examine the numbers of migrating neutrophils, endothelial F-actin and myosin II rearrangement, and endothelial MLC phosphorylation at selected times during the neutrophil migration in vitro. The results showed that pretreating endothelial cells with C3 (Rho inhibitor) or Y-27632 (Rho kinase inhibitor) significantly diminished neutrophil migration, actin polymerization, myosin II filament formation, and MLC phosphorylation normally associated with the migration. These data suggest that endothelial Rho and Rho kinase regulate transendothelial neutrophil migration by modulating the cytoskeletal events that mediate such migration.
Increased function and survival of IL-15-transduced human dendritic cells are mediated by up-regulation of IL-15Rα and Bcl-2
Authors: Tourkova Irina L , Yurkovetsky Zoya R , Gambotto Andrea , Makarenkova Valeria P , Perez Lori , Balkir Levent , Robbins Paul D , Shurin Michael R , Shurin Galina V
Published: September 2022

It has been recently demonstrated that dendritic cells (DC) coincubated with interleukin (IL)-15 express high levels of the Bcl-2 family of proteins and display an increased resistance to tumor-induced apoptotic death. Here, the phenotype, functions, and survival of human DC transduced with adenoviral vector encoding the human IL-15 gene were studied. The transduction of DC with the IL-15 gene resulted in a significant elevation of expression of CD83, CD86, and CD40 molecules, which was blocked by anti-IL-15 monoclonal antibodies. This effect was also accompanied by an increased production of IL-12 and stimulated ability of DC to induce T cell proliferation. Furthermore, transduction of DC with the IL-15 gene significantly increased their resistance to prostate cancer-induced apoptosis: Overexpression of IL-15 on DC blocked tumor-induced inhibition of Bcl-2 expression and prolonged DC survival after coincubation with tumor cells. Finally, overexpression of IL-15 in DC was associated with a higher level of expression of IL-15 receptor α chain mRNA. In summary, these results suggest that transduction of DC with the IL-15 gene markedly stimulates DC function and protects them from tumor-induced apoptosis.
Multiple determinants are involved in HIV coreceptor use as demonstrated by CCR4/CCL22 interaction in peripheral blood mononuclear cells (PBMCs)
Authors: Agrawal Lokesh , Vanhorn-Ali Zainab , Alkhatib Ghalib
Published: September 2022

Although a number of chemokine receptors display coreceptor activities in vitro, chemokine receptor 5 (CCR5) and CXC chemokine receptor 4 (CXCR4) remain the major coreceptors used by the human immunodeficiency virus type 1 (HIV-1). In this study, we used an envelope-mediated fusion assay to demonstrate low CCR4 coreceptor activity with some primary HIV-1 and simian immunodeficiency virus-1 (mac316) isolates in vitro. The coreceptor activity was sensitive to CCR4-specific antibodies and to the CCR4-specific chemokine ligand macrophage-derived chemokine (MDC)/chemokine ligand 22 (CCL22). Treatment of peripheral blood mononuclear cells (PBMCs; which express high levels of CCR4) with CCL22 caused down-modulation of endogenous CCR4 but had no significant effect on HIV-1 entry, suggesting that CCR4 may not be used as an entry coreceptor. Despite expression of other minor coreceptors on PBMCs, CCR5 and CXCR4 are preferentially used by HIV-1 isolates, as shown by chemokine-inhibition data. To determine the factors involved in this selective use, we analyzed CCR4 coreceptor activity and compared it with CCR5 use in PBMCs. We used a quantitative fluorescence-activated cell-sorting assay to estimate the numbers of CCR4 and CCR5 antibody-binding sites (ABS) on PBMCs. Although CCR4 was found on a higher percentage of CD4(+) cells, CCR5 ABS was twofold greater than CCR4 ABS on CD4(+) cells. Confocal microscopy revealed strong cell-surface CD4/CCR5 but weak CD4/CCR4 colocalization in PBMCs. Binding studies demonstrated that soluble gp120 had greater affinity to CCR5 than CCR4. The results suggested that coreceptor density, colocalization with CD4, and affinity of the viral gp120 to the coreceptor may determine preferential coreceptor use by HIV-1.
Donor T cell and host NK depletion improve the therapeutic efficacy of allogeneic bone marrow cell reconstitution in the nonmyeloablatively conditioned tumor-bearing host
Authors: Hummel Susanne , Wilms Daniela , Vitacolonna Mario , Zöller Margot
Published: September 2022

Allogeneic bone marrow cell reconstitution of the nonmyeloablatively conditioned host has the advantage that it can be tolerated in suboptimal health conditions. However, the problem of graft versus host disease (GvHD) remains. Also, graft acceptance may become delicate, and HvGD may arise. We report here on advantages/disadvantages of host natural killer (NK) depletion and graft T cell depletion in fully allogeneic, healthy and solid tumor-bearing mice. NK depletion of the “healthy” host improved the survival rate, whereas graft T cell depletion was disadvantageous. In the tumor-bearing host, graft T cell depletion was beneficial when the host was NK-depleted. Host NK depletion facilitated B lymphopoiesis, repopulation of the thymus, expansion of donor cells, and tolerance induction. The disadvantage of graft T cell depletion in the “healthy” host was a result of delayed engraftment. Because in tumor-bearing mice, host but not graft hematopoiesis was strongly impaired, donor hematopoiesis dominated. Graft T cell depletion reduced GvHD but hardly interfered with engraftment. Importantly, graft-mediated tumor reactivity appeared late and was unimpaired when the graft was T cell-depleted. Thus, concomitant depletion of host NK and donor T cells is advantageous when approaching therapeutic treatment of solid tumors by allogeneic reconstitution of the nonmyeloablatively conditioned host.
Restricted replication of primary HIV-1 isolates using both CCR5 and CXCR4 in Th2 but not in Th1 CD4+ T cells
Authors: Vicenzi Elisa , Panina-Bodignon Paola , Vallanti Giuliana , Di Lucia Pietro , Poli Guido
Published: September 2022

We have previously reported that CCR5-dependent human immunodeficiency virus type-1 (HIV-1; R5), but not CXCR4-restricted (X4) virus, efficiently replicates in T helper cell type 1 (Th1), Th2, or Th0 polyclonal T cells obtained from human umbilical cord blood (CB lines). The X4 virus restriction was env-dependent but did not occur at the level of viral entry. Here, we describe that in contrast to these monotropic HIVs, primary HIV-1 isolates capable of using CCR5 or CXCR4 indifferently for entry (i.e., R5X4 viruses) efficiently replicated in Th2 but not in Th1 CB lines. Although Th1 cells secreted significantly higher amounts of the three CCR5-binding chemokines in comparison with Th2 cells, this restriction was not explained by a defective infection of Th1 cells. Interferon-γ (IFN-γ) down-regulated CCR5 in Th1 cells and inhibited, whereas interleukin-4 (IL-4) up-regulated CXCR4 and enhanced the spreading of R5 and R5X4 viruses in polarized CB lines. However, both cytokines did not rescue the replication of X4 and dualtropic viruses in both types of CB lines or in Th1 cells, respectively, whereas addition of anti-IL-4- or anti-IFN-γ-neutralizing antibodies did not activate virus expression. These findings together suggest the existence of post-entry restriction pathways influenced by gp120 Env/chemokine coreceptor interaction that may significantly contribute to the superior capacity of R5 and R5X4 HIV-1 strains to spread in vivo in comparison to X4 monotropic viruses.
The presence of stomatin in detergent-insoluble domains of neutrophil granule membranes
Authors: Feuk-Lagerstedt Elisabeth , Samuelsson Marie , Mosgoeller Wilhelm , Movitz Charlotta , Rosqvist Åsa , Bergström Jörgen , Larsson Thomas , Steiner Marianne , Prohaska Rainer , Karlsson Anna
Published: September 2022

Neutrophil azurophil granules, traditionally regarded as the neutrophil counterpart to lysosomes, lack the lysosomal marker lysosome-associated membrane glycoprotein and have recently been suggested to be nonlysosomal secretory organelles. The membrane of the azurophil granules is poorly characterized—CD63 and CD68 are the only membrane proteins identified so far. Here, azurophil granule membranes were isolated by Percoll gradient subcellular fractionation. Using matrix-assisted laser desorption ionization time of flight mass spectrometry of tryptic peptides from an isolated protein, stomatin was identified in these membranes. Using immunoelectron microscopy and immunoblot analysis of isolated organelles, stomatin was found to be subcellularly localized, not only to the azurophil granules but also by a major part to the specific granules and by a minor part to the secretory vesicles/plasma membrane. We also show the presence of detergent-insoluble, low-density membrane domains in the plasma membrane and the granule membranes and found stomatin to be localized to these domains.
Signal transduction during Fc receptor-mediated phagocytosis
Authors: García-García Erick , Rosales Carlos
Published: September 2022

Phagocytosis is the process whereby cells engulf large particles, usually over 0.5 μm in diameter. Phagocytosis is triggered by the interaction of opsonins that cover the particle to be internalized with specific receptors on the surface of the phagocyte. The best-studied phagocytic receptors include the Fc receptors (FcR) that bind to the Fc portion of immunoglobulins. Cross-linking of FcR on the phagocyte initiates a variety of signals, which lead through the reorganization of the actin cytoskeleton, and membrane remodeling, to the formation of the phagosome. From recent data, it is becoming clear that FcR-mediated phagocytosis occurs as a series of steps that are regulated in a nonlinear manner and that signaling for phagocytosis does not terminate when the phagosome is formed. Several lipid molecules localize around the nascent phagosome and function as initiators of important signaling pathways for the late stages of phagolysosome formation. In addition, the use of particular signaling molecules may change for different receptors and may also vary depending on the activation or differentiation state of the cell. This review focuses on this new information and presents a model of our present understanding of the signal transduction events that regulate phagocytosis mediated by FcR.
Monocyte-derived dendritic cells release neopterin
Authors: Wirleitner Barbara , Reider Daniela , Ebner Susanne , Böck Günther , Widner Bernhard , Jaeger Matthias , Schennach Harald , Romani Nikolaus , Fuchs Dietmar
Published: September 2022

Increased neopterin concentrations in body fluids are found in diseases associated with activated, cell-mediated immunity including infections, autoimmune diseases, and certain malignancies. Monocytes/macrophages are known to secrete large amounts of neopterin upon stimulation with interferon-γ (IFN-γ). Ontogenetically, the major part of dendritic cells (DC) belongs to the myeloid lineage. Therefore, we investigated whether cultured monocyte-derived DC can elaborate neopterin. Cells were treated with cytokines in the presence or absence of monocyte-conditioned medium as a maturation stimulus. DC secreted an average 3.5 nmol/l neopterin. In response to IFN-γ, cells significantly increased their output of neopterin. In distinction to monocytes/macrophages, neopterin production in DC was highly sensitive to IFN-α and IFN-β. Further, lipopolysaccharides (LPS) enhanced neopterin synthesis, whereas tumor necrosis factor α, interleukin (IL)-1β, IL-2, IL-10, and IL-18 were ineffective. Simultaneously, tryptophan degradation by induction of indoleamine (2,3)-dioxygenase (IDO) was tested in stimulated cells. Our results showed that IFN-γ as well as LPS are inducers of IDO in DC.
Inhibition of murine dendritic cell activation by synthetic phosphorothioate oligodeoxynucleotides
Authors: Zhu Fu-Gang , Reich Charles F , Pisetsky David S
Published: September 2022

Depending on sequence and backbone structure, DNA can inhibit as well as stimulate immune responses. As previously shown, single-base phosphorothioate (Ps) oligodeoxynucleotides (ODN) can inhibit murine macrophage activation. To determine whether these compounds can also affect dendritic cells (DC), the effects of 30-mer Ps ODN (SdA, SdT, SdG, and SdC) on DC activation were assessed in an in vitro system. With DC preparations obtained from murine bone marrow cultured in granulocyte macrophage-colony stimulating factor, the Ps ODN blocked the production of interleukin-12 and nitric oxide induced by bacterial DNA, an immunostimulatory cytosine phosphate guanosine dinucleotide (CpG) ODN and lipopolysaccharide (LPS). Furthermore, these compounds inhibited up-regulation of costimulatory molecules CD40 and CD86 as well as major histocompatibility complex-II molecules, indicating an effect on DC maturation. Although the Ps ODN limited uptake of CpG ODN as assessed by flow cytometry, the Ps ODN did not affect LPS uptake, suggesting that these compounds inhibit DC responses by effects on downstream signaling pathways. Together, these observations extend the range of action of inhibitory ODN to DC and suggest a role of these compounds as immunomodulatory agents.
Optimal induction of antigen-specific CD8+ T cell responses requires bystander cell participation
Authors: Brice Gary T , Graber Norma L , Carucci Daniel J , Doolan Denise L
Published: September 2022

Efficient activation of specific immune responses requires a concerted interaction between T cells and antigen-presenting cells. A requirement for bystander participation of CD4+ T cells for expansion and maintenance of memory CD8+ T cells has been noted in several models, but a role with regard to effector CD8+ T responses has not been well-defined. In this report, the requirement of bystander participation for optimal induction of antigen-specific CD8+ T cell effector function was determined by directly quantitating antigen-specific interferon-γ (IFN-γ) CD8+ T cell responses by enzyme-linked immunospot assays, and by indirectly evaluating induction of the chemokine monokine induced by IFN-γ as a marker for IFN-γ-mediated effector function. Our results demonstrate that bystander cell participation, mediated by CD4+ T cell and natural killer (NK) cells, is required for optimal induction of antigen-specific CD8+ T cell effector responses. Our data further establish a novel role for NK cells in the activation of antigen-specific immune responses.
CD40 ligation and phagocytosis differently affect the differentiation of monocytes into dendritic cells
Authors: Rosenzwajg Michelle , Jourquin Frédéric , Tailleux Ludovic , Gluckman Jean Claude
Published: September 2022

That monocytes can differentiate into macrophages or dendritic cells (DCs) makes them an essential link between innate and adaptive immunity. However, little is known about how interactions with pathogens or T cells influence monocyte engagement toward DCs. We approached this point in cultures where granulocyte macrophage-colony stimulating factor (GM-CSF) and interleukin (IL)-4 induced monocytes to differentiate into immature DCs. Activating monocytes with soluble CD40 ligand (CD40L) led to accelerated differentiation toward mature CD83+ DCs with up-regulated human leukocyte antigen-DR, costimulatory molecules and CD116 (GM-CSF receptor), and down-regulation of molecules involved in antigen capture. Monocytes primed by phagocytosis of antibody-opsonized, killed Escherichia coli differentiated into DCs with an immature phenotype, whereas Zymosan priming yielded active DCs with an intermediate phenotype. Accordingly, DCs obtained from cultures with CD40L or after Zymosan priming had a decreased capacity to endocytose dextran, but only DCs cultured with CD40L had increased capacity to stimulate allogeneic T cells. DCs obtained after E. coli or Zymosan priming of monocytes produced high levels of proinflammatory tumor necrosis factor α and IL-6 as well as of regulatory IL-10, but they produced IL-12p70 only after secondary CD40 ligation. Thus, CD40 ligation on monocytes accelerates the maturation of DCs in the presence of GM-CSF/IL-4, whereas phagocytosis of different microorganisms does not alter and even facilitates their potential to differentiate into immature or active DCs, the maturation of which can be completed upon CD40 ligation. In vivo, such differences may correspond to DCs with different trafficking and T helper cell-stimulating capacities that could differently affect induction of adaptive immune responses to infections.
Interleukin-10 differently regulates monocyte chemoattractant protein-1 gene expression depending on the environment in a human monoblastic cell line, UG3
Authors: Ikeda Takashi , Sato Ken , Kuwada Naruo , Matsumura Takuya , Yamashita Takuya , Kimura Fumihiko , Hatake Kiyohiko , Ikeda Kazuma , Motoyoshi Kazuo
Published: September 2022

Interleukin (IL)-4, IL-10, and IL-13 affect monocyte/macrophage functions including regulation of cytokine production. We analyzed the regulatory effects of these cytokines on cytokine production using a human monoblastic cell line, UG3. It is interesting that IL-10 up-regulated, whereas IL-4 and IL-13 down-regulated monocyte chemoattractant protein-1 (MCP-1) production by unstimulated UG3 cells. IL-10-induced expression of MCP-1 mRNA occurred without de novo protein synthesis at transcriptional and post-transcriptional levels. The enhancement of binding activity of nuclear factor Sp1 (Sp-1) and signal transducer and activators of transcription (STAT)1 and 3 but not nuclear factor κB (NF-κB) was associated with this IL-10-induced MCP-1 expression. Furthermore, IL-10 suppressed lipopolysaccharide (LPS)-induced NF-κB binding but not Sp-1. The present results suggest IL-10 has two contrasting actions on the MCP-1 production of monocytes/macrophages, between the resting and activated conditions. The combination of activated Sp-1 and STATs is important for IL-10-induced MCP-1 expression in resting monocytes/macrophages, and the inhibition of LPS-induced NF-κB binding is crucial for down-regulation of MCP-1 by IL-10 in stimulated monocytes/macrophages.