bluuebunny/crossref_metadata_2025 huggingface dataset:
Adjuvant effect of γ-inulin is mediated by C3 fragments deposited on antigen-presenting cells
Authors: Kerekes Krisztina , Cooper Peter D , Prechl József , Józsi Mihály , Bajtay Zsuzsa , Erdei Anna
Published: September 2022

The adjuvant effect of γ-inulin, a strong activator of the alternative complement pathway, is well-known, but its exact mechanism is not revealed yet. Here, we show that macrophages, isolated from the peritoneal cavity of γ-inulin-injected mice and used as antigen-presenting cells, enhance the proliferation of antigen-specific T-cells up to 2.5-fold when compared with macrophages of nontreated animals. This effect is abrogated by the presence of anti-C3 F(ab′)2 fragments and by prior decomplementation of the donor animals with CVF. It is demonstrated that treatment of mice with the adjuvant results in deposition of C3-fragments onto the surface of peritoneal macrophages, as does in vitro incubation of the cells with γ-inulin in the presence of fresh autologous serum. Prior incubation of macrophages with γ-inulin plus serum in vitro enhances subsequent C3 production. Because it has been shown earlier that CR1/2 expressed on activated T-cells and interacting with covalently bound C3-fragments plays an important role in the augmentation of the adaptive response, our present results reveal a mechanism that contributes to the adjuvant effect of γ-inulin and point to a further link between innate and adaptive immunity.
Natural and synthetic agonists of the melanocortin receptor type 3 possess anti-inflammatory properties
Authors: Getting Stephen J , Allcock Graham H , Flower Roderick , Perretti Mauro
Published: September 2022

The effects of the natural and synthetic ligands for the melanocortin receptor type 3 (MC3-R) have been evaluated in a murine model of experimental gout. Systemic treatment of mice with γ2-melanocyte-stimulating hormone (γ2-MSH) and the synthetic agonist MTII inhibited accumulation of KC, interleukin-1 beta (IL-1β), and PMN elicited by urate crystals in the peritoneal cavity. In vitro, macrophage (Mø) activation, determined as release of KC and IL-1β, was inhibited by γ2-MSH and MTII. The mixed MC3/4-R antagonist SHU9119 prevented the inhibitory actions of γ2-MSH and MTII in vitro and in vivo, whereas the selective MC4-R antagonist HS024 was without effect. Western blotting also showed the presence of MC3-R protein on murine peritoneal Mø. Furthermore, agonism at the MC3-R evoked accumulation of cAMP within the Mø, which was inhibited by SHU9119. Thus, naturally occurring melanocortins, as well as the synthetic long-acting compound MTII, activate MC3-R on peritoneal Mø to inhibit the experimental inflammatory response.
More than destructive: neutrophil-derived serine proteases in cytokine bioactivity control
Authors: Bank Ute , Ansorge Siegfried
Published: September 2022

In addition to the mechanisms inducing the expression and secretion of cytokines under distinct pathophysiological conditions, the fate of cytokines after secretion at sites of inflammation is a field of growing interest. Proteolysis has been suggested to be a fundamental mechanism of regulating the activities of various components of the cytokine network. Evidence grows that besides highly specific cytokine converting proteases such as interleukin-1β-converting enzyme or tumor necrosis factor-converting enzyme, neutrophil-derived serine proteases are intimately involved in the modulation of the activities of cytokines and their receptors. Particularly at sites of inflammation, high amounts of the active serine proteases elastase, cathepsin G, and proteinase 3 are released from infiltrating polymorphonuclear cells in close temporal correlation to elevated levels of inflammatory cytokines, strongly indicating that these proteases are involved in the control of cytokine bioactivity and availability.
Increase of CCR1 and CCR5 expression and enhanced functional response to MIP-1α during differentiation of human monocytes to macrophages
Authors: Kaufmann Andreas , Salentin Robert , Gemsa Diethard , Sprenger Hans
Published: September 2022

Chemokines and their receptors regulate migration of leukocytes under normal and inflammatory conditions. In this study, we analyzed the CC chemokine receptor (CCR) expression of monocytes differentiatingin vitro to macrophages. We observed a time-dependent change of expression and functional responsiveness of CCR1, CCR2, and CCR5 within 48 h. Whereas freshly harvested monocytes were strongly attracted by monocyte chemotactic protein 1 (MCP-1), a specific ligand for CCR2, only a weak response was observed to macrophage inflammatory protein 1α (MIP-1α), which binds to CCR1 and CCR5. In striking contrast, differentiated macrophages displayed a strong chemotactic response to MIP-1α and only a weak response to MCP-1. These findings were paralleled by intracellular calcium shifts. During the time course of monocyte to macrophage differentiation, mRNA levels and surface expression of CCR2 decreased, whereas that of CCR1 and CCR5 increased. The time-dependent switch from CCR2 on monocytes to CCR1 and CCR5 on mature macrophages reflects a functional change belonging to the differentiation process of monocytes to macrophages and may form the basis for a differential responsiveness of monocytes and macrophages to distinct sets of chemokines.
Involvement of protein kinases in the potentiation of lipopolysaccharide-induced inflammatory mediator formation by thapsigargin in peritoneal macrophages
Authors: Chen Bing-Chang , Hsieh Shie-Liang , Lin Wan-Wan
Published: September 2022

We have explored the regulatory roles played by Ca2+-dependent signaling on lipopolysaccharide (LPS)-induced nitric oxide (NO), prostaglandin E2 (PGE2), tumor necrosis factor α (TNF-α), and interleukin-6 (IL-6) release in mouse peritoneal macrophages. To elevate intracellular Ca2+, we used thapsigargin (TG) and UTP. Although LPS alone cannot stimulate NO synthesis, co-addition with TG, which sustainably increased [Ca2+]i, resulted in NO release. UTP, via acting on P2Y6 receptors, can stimulate phosphoinositide (PI) turnover and transient [Ca2+]i increase, however, it did not possess the NO priming effect. LPS alone triggered the release of PGE2, TNF-α, and IL-6; all of which were potentiated by the presence of TG, but not of UTP. The stimulatory effect of LPS plus TG on NO release was inhibited by the presence of Ro 31-8220, Go6976, KN-93, PD 098059, or SB 203580, and abolished by BAPTA/AM and nuclear factor κB (NF-κB) inhibitor, PDTC. PGE2, TNF-α, and IL-6 release by LPS alone were attenuated by Ro 31-8220, Go6976, PD 098059, SB 203580, and PDTC. Using l-NAME, soluble TNF-α receptor, IL-6 antibody, NS-398, and indomethacin, we performed experiments to understand the cross-regulation by the four mediators. The results revealed that TNF-α up-regulated NO, PGE2, and IL-6 synthesis; PGE2 up-regulated NO, but down-regulated TNF-α synthesis; and PGE2 and IL-6 mutually up-regulated reciprocally. Taken together, murine peritoneal macrophages required a sustained [Ca2+]i increase, which proceeds after TG, but not UTP, stimulation, to enhance LPS-mediated release of inflammatory mediators, particularly for NO induction. Activation of PKC-, ERK-, and p38 MAPK-dependent signaling also are essential for LPS action. The positive regulatory interactions among these mediators might amplify the inflammatory response caused by endotoxin.
Dietary fatty acids influence the production of Th1- but not Th2-type cytokines
Authors: Wallace Fiona A , Miles Elizabeth A , Evans Carl , Stock Theresa E , Yaqoob Parveen , Calder Philip C
Published: September 2022

C57Bl6 mice were fed for 6 weeks on a low-fat diet or on high-fat diets containing coconut oil (rich in saturated fatty acids), safflower oil [rich in n-6 polyunsaturated fatty acids (PUFAs)], or fish oil (rich in n-3 PUFAs) as the main fat sources. The fatty acid composition of the spleen lymphocytes was influenced by that of the diet fed. Thymidine incorporation into concanavalin A-stimulated spleen lymphocytes and interleukin (IL)-2 production were highest after feeding the coconut oil diet. Interferon (IFN)-γ production was decreased by safflower oil or fish oil feeding. IL-4 production was not significantly affected by diet, although production was lowest by lymphocytes from fish oil-fed mice. The ratio of production of Th1- to Th2-type cytokines (determined as the IFN-γ/IL-4 ratio) was lower for lymphocytes from mice fed the safflower oil or fish oil diets. After 4 h of culture, IL-2 mRNA levels were higher in cells from mice fed coconut oil, and IFN-γ mRNA levels were higher in cells from mice fed coconut oil or safflower oil. After 8 h of culture, IL-2, IFN-γ, and IL-4 mRNA levels were lowest in cells from mice fed fish oil. The ratio of the relative levels of IFN-γ mRNA to IL-4 mRNA was highest in cells from mice fed coconut oil and was lowest in cells of mice fed fish oil. The influence of individual fatty acids on IL-2 production by murine spleen lymphocytes was examined in vitro. Although all fatty acids decreased IL-2 production in a concentration-dependent manner, saturated fatty acids were the least potent and n-3 PUFAs the most potent inhibitors, withn-6 PUFAs falling in between in terms of potency. It is concluded that saturated fatty acids have minimal effects on cytokine production. In contrast, PUFAs act to inhibit production of Th1-type cytokines with little effect on Th2-type cytokines; n-3 PUFAs are particularly potent. The effects of fatty acids on cytokine production appear to be exerted at the level of gene expression.
Chemokines stimulate human T lymphocyte transendothelial migration to utilize VLA-4 in addition to LFA-1
Authors: Ding Ziqiang , Xiong Ke , Issekutz Thomas B
Published: September 2022

Lymphocyte infiltration in inflammation is induced by the dual actions of chemokines and cell adhesion molecules. The role of LFA-1 and VLA-4 in chemokine-induced T cell transendothelial migration (TEM) across cytokine-activated endothelium has not been examined. LFA-1, but not VLA-4, mediated blood T cell TEM to RANTES, macrophage inflammatory protein-1α (MIP-1α), and stromal cell-derived factor-1 (SDF-1), and across tumor necrosis factor α (TNF-α) or interferon-γ (IFN-γ) -stimulated endothelial cells (EC). Chemokine stimulation in combination with TNF-α activation of EC induced TEM, which was partially mediated by VLA-4. SDF-1 increased a β1-integrin activation epitope on T cells and enhanced VLA-4-mediated adhesion. Thus, LFA-1 mediates TEM under most conditions, but VLA-4 can also mediate TEM, although, in contrast to LFA-1, this requires exogenous chemokines and EC activation. In addition, an LFA-1- and VLA-4-independent pathway of lymphocyte TEM can also be induced by SDF-1.
The effects of extracellular pH on immune function
Authors: Lardner Anne
Published: September 2022

The effect of alterations in extracellular pH on cellular and humoral immune function is reviewed. Because acidic pH predominates at inflammatory loci and other sites of immune activity, most studies to date focus on the effect of acidic rather than alkaline pH. Investigations on polymorphonuclear leukocytes demonstrate mainly inhibition of chemotaxis, respiratory activity, and bactericidal capacity at reduced pH. Evidence of impaired lymphocyte cytotoxicity and proliferation at acidic pH is also beginning to emerge. Many of the clinical acidoses are accompanied similarly by immunodeficiency. Studies on macrophages and eosinophils are few and inconclusive. A small number of studies demonstrate acid-induced activation of complement proteins and the alternative complement pathway, plus increased antibody-binding to leukocytes at lowered pH. A differential effect of acidic pH on humoral and cellular immunity may, therefore, exist. Increasing recognition of the significance of extracellular pH in relation to immune function warrants further studies in this presently incomplete but rewarding field.
Sulfhydryl-2 domain-containing protein tyrosine phosphatase-1 is not a negative regulator of interleukin-4 signaling in murine mast cells
Authors: White Erik D , Andrews Ryan P , Hershey Gurjit K Khurana
Published: September 2022

Sulfhydryl-2 domain-containing tyrosine phosphatase-1 (SHP-1) has an important role in the negative regulation of many receptors including the interleukin (IL)-4 receptor. Motheaten mice (me/me) have a homozygous mutation in SHP-1 and do not possess functional SHP-1. Pre-B-cell lines derived from me/me mice have been reported to display prolonged IL-4-dependent activation of signal transducer and activator of transcription-6 (Stat6). We evaluated IL-4-dependent Stat6 activation and Fcɛ receptor 1 (FcɛRI) modulation in bone marrow-derived mast cells (BMMCs) from me/me and wild-type mice. IL-4 down-regulated FcɛRI expression in wild-type BMMCs but had no effect on FcɛRI expression in me/me BMMCs. Furthermore, me/me mast cells did not exhibit enhanced or prolonged IL-4-induced Stat6 activation compared with wild-type cells, indicating that mast cells possess alternative tyrosine phosphatases that are responsible for down-regulating Stat6 or can substitute for SHP-1. Thus, SHP-1 is not a negative regulator of IL-4 signaling in BMMCs. These results demonstrate the complexity and cellular specificity of these signaling pathways and indicate a previously unrecognized role for SHP-1 in murine mast cells.
Priming effects of substance P on calcium changes evoked by interleukin-8 in human neutrophils
Authors: Dianzani Chiara , Lombardi Grazia , Collino Massimo , Ferrara Cinzia , Cassone Maria Chiara , Fantozzi Roberto
Published: September 2022

The neurokinin (NK) substance P (SP), which is a mediator of neurogenic inflammation, has been reported to prime human polymorphonuclear neutrophils (PMNs). The priming effects of SP on PMNs activated by recombinant interleukin-8 (rIL-8) were investigated. SP enhanced, in a dose- and time-dependent way, the rise in cytosolic free-calcium concentration, [Ca2+]i, evoked by the chemokine. The priming effects of SP were abolished by exposing PMNs to a calcium-free medium supplemented with EGTA. The C-terminal peptides SP(4–11) and SP(6–11) but not the N-terminal peptide SP(1–7) shared the priming effects of SP. The selective NK-1 receptor agonist [Sar-9, Met(O)2-11]SP mimicked the effects of SP, which were not reproduced by the selective NK-2 receptor agonist [βAla-8]-NKA(4–10) or the selective NK-3 agonist senktide. Two selective NK-1 antagonists, CP96,345 and L703,606, dose dependently inhibited SP priming effects. These results demonstrated that SP primes PMNs exposed to rIL-8 and suggested that SP priming effects are receptor mediated.
Retardation of early-onset PMA-induced apoptosis in mouse neutrophils deficient in myeloperoxidase
Authors: Tsurubuchi Tetsuto , Aratani Yasuaki , Maeda Nobuyo , Koyama Hideki
Published: September 2022

Neutrophil apoptosis is a mechanism involved in the resolution of inflammation. To explore the role of hypochlorous acid (HOCl) produced by neutrophils while they are undergoing apoptosis, we compared the rates of apoptosis in neutrophils isolated from normal mice and from myeloperoxidase (MPO)-deficient mice, which are unable to generate HOCl. Apoptosis in MPO-deficient neutrophils stimulated by phorbol myristate acetate (PMA) was significantly slower than in normal neutrophils during 3 h of incubation. Exposure of normal neutrophils to H2O2 together with PMA resulted in a dramatic acceleration of apoptosis, and almost all of the cells revealed apoptotic morphology at 1 h. This acceleration was inhibited by cytochrome c, a superoxide scavenger. Conversely, in MPO-deficient neutrophils activated with PMA and H2O2, little acceleration was observed before 1 h, although it gradually increased thereafter. This retardation was almost completely reversed when MPO or HOCl was exogenously added. These results suggest that coexistence of HOCl and superoxide accelerates the early onset of neutrophil apoptosis.
Nitric oxide induces murine thymocyte apoptosis by oxidative injury and a p53-dependent mechanism
Authors: Gordon Sherilyn A , Abou-Jaoude Walid , Hoffman Rosemary A , McCarthy Susan A , Kim Young-Myeong , Zhou Xin , Zhang Xiao-Ru , Simmons Richard L , Chen Yue , Schall Laura , Ford Henri R
Published: September 2022

Previously, we showed that NO induces thymocyte apoptosis via acaspase-1-dependent mechanism [1]. In the present study,we investigated the role of heme oxygenase, catalase, bax, and p53 inthis process. The NO donor, S-nitroso-N-acetyl penicillamine (SNAP),induced DNA fragmentation in thymocytes in a time- andconcentration-dependent way. SNAP (100 μM) induced 50–60%apoptosis; higher doses did not increase the rate of apoptosissignificantly. SNAP decreased catalase and heme iron (Fe) levelswithout affecting superoxide dismutase, glutathione, or total Fe storesin thymocytes. SNAP significantly increased the expression of hemeoxygenase 1 (HSP-32), p53, and bax but notbcl-2. Treatment with the heme oxygenase inhibitor, tinprotoporphyrin IX inhibited SNAP-induced thymocyte apoptosis.Furthermore, thymocytes from p53 null mice were resistantto NO-induced apoptosis. Our data suggest that NO may induce itscytotoxic effects on thymocytes by modulating heme oxygenase andcatalase activity as well as up-regulating pro-apoptotic proteinsp53 and bax.
Functional heterogeneity in liver and lung macrophages
Authors: Laskin Debra L , Weinberger Barry , Laskin Jeffrey D
Published: September 2022

Although initially considered merely “scavenger cells” that participate in immunologic responses only after B and T lymphocytes have performed their biological tasks, more recent evidence suggests that macrophages play a key role in host defense as well as in the maintenance of normal tissue structure and function. For macrophages to perform their biological functions, they must be activated. This involves up-regulation of an array of signaling pathways resulting in altered gene expression and increased biochemical and functional activity. Macrophages have been identified in almost all tissues of the body. However, the basal activity of these cells, as well as their ability to respond to inflammatory mediators, varies considerably with their location. In addition, even within a particular tissue, there is evidence of macrophage heterogeneity. The largest populations of macrophages in the body are located in the liver and lung. Because of the unique attributes of these tissues, hepatic and pulmonary macrophages play essential roles not only in nonspecific host defense but also in the homeostatic responses of these tissues. In this review, the functional and biochemical activities of macrophages localized in the liver and lungs are compared. Evidence suggests that these represent distinct cell populations with unique functions and responsiveness to inflammatory agents.
Effects of hypertonic saline on expression of human polymorphonuclear leukocyte adhesion molecules
Authors: Thiel M , Buessecker F , Eberhardt K , Chouker A , Setzer F , Kreimeier U , Arfors K-E , Peter K , Messmer K
Published: September 2022

Hypertonic saline prevents vascular adherence of neutrophils and ameliorates ischemic tissue injury. We hypothesized that hypertonic saline attenuatesN-formyl-methionyl-leucyl-phenylalanine (fMLP)-stimulated expression of adhesion molecules on human polymorphonuclear leukocytes (PMNLs). fMLP-stimulated up-regulation of β2-integrins was diminished by hypertonic saline but not by hypertonic choline chloride-, mannitol-, or sucrose-modified Hanks’ buffered salt solution. Shedding of l-selectin was decreased by hypertonic saline and choline chloride but not by hypertonic mannitol or sucrose. When the effects of hypertonic sodium chloride- and choline chloride-modified media were compared, neither solution affected fMLP-receptor binding but both equally inhibited fMLP-stimulated increase in intracellular calcium, ionophore A23187, and phorbol myristate acetate (PMA)-stimulated numerical up-regulation of β2-integrins. Analysis of mitogen-activated protein (MAP) kinases p38 and p44/42 for phosphorylation revealed that hypertonic solutions did not differ in preventing fMLP-stimulated increases in phospho-p38 and phospho-p44/42. Resting PMNLs shrunk by hypertonic saline increased their volume during incubation and further during chemotactic stimulation. Addition of amiloride further enhanced inhibition of up-regulation of β2-integrins. No fMLP-stimulated volume changes occurred in PMNLs exposed to hypertonic choline chloride, resulting in significant cell shrinkage. Results suggest a sodium-specific inhibitory effect on up-regulation of β2-integrins of fMLP-stimulated PMNLs, which is unlikely to be caused by alterations of fMLP receptor binding, decrease in cytosolic calcium, attenuation of calcium or protein kinase C-dependent pathways, suppression of p38- or p44/42 MAP kinase-dependent pathways, or cellular ability to increase or decrease volumes.
Contributions ofNeisseria meningitidisLPS and non-LPS to proinflammatory cytokine response
Authors: Sprong Tom , Stikkelbroeck Nike , van der Ley Peter , Steeghs Liana , van Alphen Loek , Klein Nigel , Netea Mihai G , van der Meer Jos W M , van Deuren Marcel
Published: September 2022

To determine the relative contribution of lipopolysaccharide (LPS) and non-LPS components of Neisseria meningitidis to the pathogenesis of meningococcal sepsis, this study quantitatively compared cytokine induction by isolated LPS, wild-type serogroup B meningococci (strain H44/76), and LPS-deficient mutant meningococci (strain H44/76[pLAK33]). Stimulation of human peripheral-blood mononuclear cells with wild-type and LPS-deficient meningococci showed that non-LPS components of meningococci are responsible for a substantial part of tumor necrosis factor (TNF)-α and interleukin (IL)-1β production and virtually all interferon (IFN)-γ production. Based on tricine sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis of LPS in proteinase K-treated lysates of N. meningitidis H44/76, a quantitative comparison was made between the cytokine-inducing capacity of isolated and purified LPS and LPS-containing meningococci. At concentrations of >107 bacteria/mL, intact bacteria were more potent cytokine inductors than equivalent amounts of isolated LPS, and cytokine induction by non-LPS components was additive to that by LPS. Experiments with mice showed that non-LPS components of meningococci were able to induce cytokine production and mortality. The principal conclusion is that non-LPS parts of N. meningitidis may play a role in the pathogenesis of meningococcal sepsis by inducing substantial TNF-α, IL-1β, and IFN-γ production.
Augmented TNF-α and IL-10 production by primed human monocytes following interaction with oxidatively modified autologous erythrocytes
Authors: Liese Amy M , Siddiqi Muhammad Q , Siegel John H , Denny Thomas , Spolarics Zoltán
Published: September 2022

The presence of dysfunctional/damaged red blood cells (RBCs) has been associated with adverse clinical effects during the inflammatory response. The aim of this study was to elucidate whether oxidatively modified, autologous RBCs modulate monocyte cytokine responses in humans. Monocyte tumor necrosis factor α (TNF-α) and IL-10 production was measured in whole blood from healthy volunteers using ELISA and flow cytometry. Oxidatively modified RBCs (15 mM phenylhydrazine, 1 h, OX-RBC) or vehicle-treated RBCs (VT-RBC) opsonized by autologous serum were administered alone or in combination with one of three priming agents: E. coli lipopolysaccharide (LPS, 0.2 ng/ml), zymosan A (1 mg/ml), or phorbol 12-myristate 13-acetate (PMA, 50 ng/ml). OX-RBC or VT-RBC alone did not result in the release of TNF-α or IL-10. LPS, zymosan, and PMA caused marked and dose-dependent increases in TNF-α and IL-10 production. Addition of OX-RBC augmented the LPS-, zymosan-, and PMA-induced TNF-α release by approximately 100%. OX-RBC augmented LPS- and zymosan-induced IL-10 release by 400–600%. Flow cytometry analyses showed that monocytes were responsible for TNF-α and IL-10 production in whole blood. The presence of OX-RBC alone increased the complexity of CD14+ monocytes but caused no cytokine production. LPS alone induced cytokine production without altering cell complexity. After the combined (OX-RBC+LPS) treatment, monocytes of high complexity were responsible for TNF-α production. The presence of mannose or galactose (at 10–50 mM) did not alter the observed augmentation of cytokine production by OX-RBC, suggesting that lectin receptors are not involved in the response. These studies indicate that the interaction between damaged autologous erythrocytes and monocytes has a major impact on the cytokine responses in humans. An augmented cytokine production by the mononuclear phagocyte system may adversely affect the clinical course of injury and infections especially in genetic or acquired RBC diseases or after transfusions.
A novel bioactive 31-amino acid endothelin-1 is a potent chemotactic peptide for human neutrophils and monocytes
Authors: Cui Ping , Tani Kenji , Kitamura Hiroko , Okumura Yuushi , Yano Mihiro , Inui Daisuke , Tamaki Toshiaki , Sone Saburo , Kido Hiroshi
Published: September 2022

Endothelin (ET)-1(1-31) is a novel 31-amino acid-length peptide derived from big ET-1 by chymase or other chymotrypsin-type proteases and is a major ET derivative in human neutrophils. In this study, we revealed that ET-1(1-31), but not big ET, exhibited chemotactic activities toward human neutrophils and monocytes as an inflammatory mediator, although the effects were less potent than those of formyl-methionyl-leucyl-phenylalanine or interleukin-8. However, the chemotactic effects of ET-1(1-31) were much greater than those of the 21-amino acid ET-1, ET-1(1-21). Checkerboard analyses revealed that the effects are chemotactic rather than chemokinetic. The effects of ET-1(1-31) are not mediated by interleukin-8 or monocyte chemoattractant protein-1. The chemotactic effects and an increase in intracellular-free Ca2+ caused by ET-1(1-31) were significantly inhibited by BQ123, an ETA receptor antagonist, but not by BQ788, an ETB receptor antagonist, suggesting that ET-1(1-31) mediates chemotaxis through an ETA or ETA-like receptor.
A small-molecule antagonist of LFA-1 blocks a conformational change important for LFA-1 function
Authors: Woska Joseph R , Shih Daw-tsun , Taqueti Viviany R , Hogg Nancy , Kelly Terence A , Kishimoto Takashi K
Published: September 2022

Lymphocyte function-associated antigen(LFA)-1/intercellular adhesion molecule (ICAM)-1interactions mediate several important steps in the evolution of animmune response. LFA-1 is normally expressed in a quiescent state onthe surface of leukocytes and interacts weakly with its ligands ICAM-1,-2, and -3. LFA-1 activity may be regulated by receptor clustering andby increasing the affinity of LFA-1 for its ligands. Affinitymodulation of LFA-1 has been shown to occur via a conformational changein the LFA-1 heterodimer that can be detected by using monoclonalantibody 24 (mAb24). We have recently described a small-moleculeantagonist of LFA-1, BIRT 377, that demonstrates selective in vitro andin vivo inhibition of LFA-1/ICAM-1-mediated binding events. We nowdemonstrate that BIRT 377 blocks the induction of the mAb24 reporterepitope on LFA-1 on the surface of SKW-3 cells treated with variousagonists known to induce high-affinity LFA-1. These data imply thatBIRT 377 exerts its inhibitory effects by preventing up-regulation ofLFA-1 to its high-affinity conformation.
Hemofiltrate CC chemokines with unique biochemical properties: HCC-1/CCL14a and HCC-2/CCL15
Authors: Forssmann Ulf , Mägert Hans-Jürgen , Adermann Knut , Escher Sylvia E , Forssmann Wolf-Georg
Published: September 2022

The hemofiltrate CC chemokines CCL14a (formerly HCC-1), CCL14b (formerly HCC-3), and CCL15 (formerly HCC-2) are encoded by mono- as well as bicistronic transcripts from a tandem gene arrangement on human chromosome 17q11.2. The transcription and splicing into several mono- and bicistronic transcripts of this gene complex are unique for human genes. No corresponding mechanism is known in nonprimate mammalian species such as mice and rats. The extremely high concentration of CCL14a in human plasma is exceptional for chemokines and led to the identification of this chemokine. Several molecular forms of CCL14a have been isolated and investigated. The mature propeptide CCL14a(1–74) is a low-affinity agonist of CCR1 which is converted to a high-affinity agonist of CCR1 and CCR5 on proteolytic processing by serine proteases. In contrast, CCL15 is characterized using molecular forms deduced from the mRNA/cDNA and shown to activate cells via CCR1 and CCR3, also dependent on the amino-terminal length. Hemofiltrate CC chemokines are chemoattractants for different types of leukocytes including monocytes, eosinophils, T cells, dendritic cells, and neutrophils. In this review, we emphasize the genomic organization, expression patterns, and biochemical properties of CCL14a, CCL14b, and CCL15. We report results of significance for the development of therapeutic strategies, especially concerning HIV infection and inflammatory diseases.
Interleukin-12 increases interleukin 8 production and release by human polymorphonuclear neutrophils
Authors: Ethuin Frédéric , Delarche Charlotte , Benslama Sylvie , Gougerot-Pocidalo Marie-Anne , Jacob Laurent , Chollet-Martin Sylvie
Published: September 2022

Interleukin (IL) 12 is a heterodimeric cytokine mainly produced by phagocytes—important target cells for IL-12 in particular with a chemotactic effect—and antigen-presenting cells in response to various microorganisms. Because IL-8 is a strong chemokine for polymorphonuclear neutrophils (PMNs), we investigated the effect of IL-12 on PMN IL-8 production. IL-12 alone had no significant effect, but with lipopolysaccharide (LPS) it was additive at both protein and mRNA levels. Actinomycin D at the beginning of culture inhibited IL-8 mRNA induction, whereas late addition affected IL-8 transcript stability, suggesting gene transcription involvement. Results with parthenolide and tyrphostin AG490 suggest that nuclear factor-κB and signal transducer and activator of transcription 4 play a role. The IL-12 additive effect was restricted to IL-8 release, with no action on cell-associated IL-8. IL-12 additive effects occurred after 18 h of culture, with no marked up-regulation of IL-12 receptor expression, and were blocked by actinomycin D added after 16 h of culture. Tumor necrosis factor (TNF) α and interferon (IFN) γ had intermediate roles; their specific inhibition reduced IL-12'SSSs effect. IL-12's chemotactic mechanism seemed mediated by overproduction and release of IL-8 by human PMNs in the presence of LPS, an effect involving TNF-α and IFN-γ secretion. These results point to a new role for IL-12 in inflammation, through an autocrine amplification loop.
Microenvironmental influence on macrophage regulation of angiogenesis in wounds and malignant tumors
Authors: Crowther M , Brown N J , Bishop E T , Lewis C E
Published: September 2022

Angiogenesis is the development of blood vessels from an existing vasculature. This process is fundamental to both physiological wound healing and the growth of malignant tumors, as it restores or creates a blood supply to growing tissue. In both cases, the release of angiogenic molecules by macrophages recruited to the wound or tumor site is central to the formation of these neovessels. Reduced vascular perfusion in tissues generates tissue ischemia and a marked reduction in local levels of oxygen (hypoxia) and glucose. Cells adapt by switching to anaerobic metabolic pathways, with a concomitant increase in lactate production and reduction in extracellular pH. In tumors, these microenvironmental “stress” factors stimulate tumor cells to secrete a wide array of proangiogenic cytokines and enzymes, promoting the re-establishment of a local vascular supply. Here we review the evidence that these stress factors, in particular hypoxia and high lactate levels, stimulate macrophages to perform similar proangiogenic functions in both tumors and wounds. The resolution of wounds results in restoration of tissue integrity and perfusion, and macrophage presence is reduced to preinjury levels. However, in tumors a high number of macrophages persists and might contribute to the ongoing growth, neovascularization, and metastasis of malignant cells.
Spontaneous formation of germinal centers in autoimmune mice
Authors: Luzina Irina G , Atamas Sergei P , Storrer Catherine E , daSilva Ludmila C , Kelsoe Garnett , Papadimitriou John C , Handwerger Barry S
Published: September 2022

The mechanisms of autoantibody production are not well understood. Germinal centers (GC) may be important sites of immune disregulation in autoimmune diseases. In this study, we document the presence of spontaneous GC formation in the spleens of several autoimmune mouse strains that spontaneously develop autoimmune Type I diabetes and a lupus-like disease. In contrast, mouse strains that do not develop lupus did not exhibit spontaneous formation of GC. In all of the autoimmune strains studied, GC were present at 1–2 months of age, a time that closely parallels the appearance of autoantibodies. Like the GC that develop after purposeful immunization, GC in autoimmune mice contained B220+, PNA+, and GL-7+ B cells, and FDC-M1+ follicular dendritic cells. In addition, spontaneously formed GC in autoimmunity and those caused by immunization were abrogated in a similar way by a short-term treatment with anti-CD40 ligand antibody. These data indicate that spontaneously forming GC in autoimmunity are similar to those appearing after purposeful immunization.
Involvement of p38-mitogen-activated protein kinase in staphylococcus aureus-induced neutrophil apoptosis
Authors: Lundqvist-Gustafsson Helen , Norrman Sara , Nilsson Jessica , Wilsson Åsa
Published: September 2022

Apoptosis occurred in human neutrophils within an hour of exposure to viable serum-opsonized Staphylococcus aureus, as indicated by appearance of cells with condensed nuclei, fragmented DNA, and increased phosphatidylserine exposure. In contrast, serum-opsonized, heat-killed S. aureus did not induce apoptosis. This discrepancy could not be explained by differences in bacterial uptake or total NADPH-oxidase activity. Suppressing phagocytosis by pretreating the neutrophils with cytochalasin b or by using nonopsonized bacteria did not prevent apoptosis. A supernatant from bacteria grown for 2 h in nutrient broth had a strong proapoptotic influence that was abrogated by heat treatment. Exposure to viableS. aureus or supernatant also led to activation of p38-mitogen-activated protein kinase in the neutrophils. Inhibition of this kinase with SB203580 reduced the apoptosis-inducing capacity of both bacteria and supernatant. We conclude that S. aureus activates p38-mitogen-activated protein kinase in neutrophils and induces apoptosis, probably mediated by a bacteria-derived soluble factor(s)
C1qRp, a myeloid cell receptor in blood, is predominantly expressed on endothelial cells in human tissue
Authors: Fonseca Maria I , Carpenter Philip M , Park Minha , Palmarini Gail , Nelson Edward L , Tenner Andrea J
Published: September 2022

C1qRp is a type I cell surface glycoprotein that has been shown to enhance ingestion of suboptimally opsonized targets by phagocytes in vitro. In this study, we developed and characterized polyclonal antibodies to study the tissue distribution of this receptor targeted to either the N- or C-terminal portion of the molecule. C1qRp was detected in vascular endothelial cells and in a subset of pyramidal neurons in the brain, as well as neutrophils, but it was absent in most tissue macrophages. Analysis of in vitro differentiation of blood monocytes to dendritic cells demonstrated a down-regulation of the receptor as monocytes differentiate to dendritic cells, providing a possible explanation for the lack of reactivity of these cells in tissue. The predominant presence of C1qRp in endothelial cells, while compatible with a phagocytic role in host defense and/or clearance of cellular material, suggests other possible novel roles for this receptor.
Interplay between telomere length and telomerase in human leukocyte differentiation and aging
Authors: Weng Nan-ping
Published: September 2022

Blood leukocytes derive from bone marrow hematopoietic stem cells anddifferentiate into multiple types of mature cells that includegranulocytes, monocytes, mast cells of myeloid lineage, and T and Blymphocytes of lymphoid lineage. Their distinctive paths ofdifferentiation and unique roles in immune response provide a model forcomparative analysis of biological parameters, such as telomere lengthand telomerase activity, in different types of leukocytes. Age has alsobeen associated with the decline in immune functions and with theattrition of telomere length in leukocytes. This review will summarizerecent progress in the study of telomere length and telomeraseexpression in leukocytes during differentiation and aging. In addition,I will attempt to shed new light on the roles of telomere andtelomerase in leukocyte function and potential clinicalinterventions.
MIP-1α regulates CD4+ T cell chemotaxis and indirectly enhances PMN persistence inPseudomonas aeruginosacorneal infection
Authors: Kernacki Karen A , Barrett Ronald P , McClellan Sharon , Hazlett Linda D
Published: September 2022

The role of macrophage inflammatory protein-1α (MIP-1α) in cell infiltration into Pseudomonas aeruginosa-infected cornea and subsequent disease was examined. Greater amounts of the chemokine (protein and mRNA) were found in the infected cornea of susceptible B6 (“cornea perforates”) versus resistant BALB/c (“cornea heals”) mice from 1 to 5 days postinfection. Treatment of BALB/c mice with recombinant (r) MIP-1α exacerbated disease and was associated with an increased number of neutrophils (PMNs) in the cornea. Treatment of BALB/c mice with rMIP-1α also induced recruitment of activated CD4+ T cells into the affected cornea, converting resistant to susceptible mice. Depleting CD4+ T cells in r-treated BALB/c mice significantly decreased PMNs in cornea tissue, suggesting that T cells regulate persistence of PMNs at this site. In B6 mice, administration of neutralizing MIP-1α polyclonal antibody also significantly reduced PMN numbers and pathology. Collectively, evidence is provided that MIP-1α directly contributed to CD4+ T cell recruitment and indirectly to PMN persistence in the infected cornea.
IL-17: prototype member of an emerging cytokine family
Authors: Aggarwal Sudeepta , Gurney Austin L
Published: September 2022

IL-17 is a potent proinflammatory cytokine produced by activated memory T cells. The large-scale sequencing of the human and other vertebrate genomes has revealed the presence of additional genes encoding proteins clearly related to IL-17, thus defining a new family of cytokines. There are at least six members of the IL-17 family in humans and in mice. Initial characterization suggests that like IL-17, several of these newly identified molecules have the ability to modulate immune function. Neither the IL-17 family nor the cognate receptors that have been identified for these molecules bear obvious sequence similarity to other known families of proteins. Thus, they represent a distinct signaling system that appears to have been highly conserved across vertebrate evolution. The potent inflammatory actions that have been identified for several of these factors and the emerging associations with major human diseases suggest that these proteins may have significant roles in inflammatory processes.
NK-like CD8+ cells in immunologically naïve neonatal calves that respond to dendritic cells infected withMycobacterium bovisBCG
Authors: Hope Jayne C , Sopp Paul , Howard Chris J
Published: September 2022

Pre-exposure to environmental mycobacteria and induction of an inappropriately biased immune response may be major factors affecting the efficacy of BCG; vaccination of neonates that have not been exposed to environmental mycobacteria may induce more effective immunity. Responses of neonatal calves to mycobacterial antigens using dendritic cells (DC) as antigen-presenting cells were investigated. In nonvaccinated, immunologically naive calves as young as 1 day old, a population of CD8+ cells proliferated and produced IFN-γ in response to BCG-infected DC. CD3− CD8+ NK-like and CD3+ CD8+ T cells were evident within the responding CD8+ population. The response was not MHC-restricted. The NK-like CD3− cells were the major population producing IFN-γ. The presence of mycobacteria-reactive, IFN-γ-secreting CD8+ NK cells in neonatal calves may have important consequences for the induction of a Th1-biased immune response.
The role of growth hormone in T-cell development and reconstitution
Authors: Welniak Lisbeth A , Sun Rui , Murphy William J
Published: September 2022

Growth hormone (GH), directly or through GH-induction of insulin-like growth factor (IGF)-1, has been implicated in lymphocyte development and function. Recent studies have questioned the role of GH and IGF-1 in immune responses. This review examines experimental data describing the immunoregulatory function of GH and attempts to reconcile the literature.
Enhanced proinflammatory response to endotoxin after priming of macrophages with lead ions
Authors: Flohé Stefanie B , Brüggemann Jutta , Herder Christian , Goebel Carsten , Kolb Hubert
Published: September 2022

Exposure to lead ions strongly enhances the susceptibility of rodents to endotoxin shock and parasitical infections. Macrophages play a key role during the immune response to lipopolysaccharide (LPS) and during the defense against parasites and might be a target of lead. In the present study, bone marrow-derived macrophages (BMMφ) pretreated with lead chloride prior to stimulation with LPS were analyzed for their release of immune mediators. Lead-pretreated cells released up to tenfold increased amounts of tumor necrosis factor-α (TNF-α), interleukin (IL)-6, IL-12, and prostaglandin E2 (PGE2) but less IL-10 compared with controls. These effects were paralleled by enhanced mRNA levels and were dependent on the duration of lead pretreatment. Inhibition of protein kinase C or of protein synthesis during the priming phase blocked the lead-induced increase of TNF-α and IL-6 release. In conclusion, lead ions prime ΒMMφ for enhanced proinflammatory cytokine secretion in response to LPS, likely by activation of protein kinase C and subsequent synthesis of an unidentified mediator.
RAGE-mediated neutrophil dysfunction is evoked by advanced glycation end products (AGEs)
Authors: Collison Kate S , Parhar Ranjit S , Saleh Soad S , Meyer Brian F , Kwaasi Aaron A , Hammami Muhammad M , Schmidt Ann Marie , Stern David M , Al-Mohanna Futwan A
Published: September 2022

The accumulation of advanced glycation end products (AGEs) in the tissue and serum of subjects with diabetes has been linked to the pathogenesis of vascular complications. Because diabetes may be also complicated by increased susceptibility to recurrent infection, we investigated the effects of AGEs on human neutrophils, because their burst of activity immediately upon engagement of pathogens or other inflammatory triggers is critical to host response. We demonstrate the presence of receptor for advanced glycation end products (RAGE) at the message and protein levels. We also demonstrate that AGE albumin (but not control albumin) binds with high affinity to human neutrophils (Kd of 3.7±0.4 nM). The binding was blocked almost completely by excess soluble RAGE, anti-RAGE antibodies, or antibodies to CML-modified albumin. AGE albumin induced a dose-dependent increase in intracellular-free calcium as well as actin polymerization. Further, AGE albumin inhibited transendothelial migration and Staphylococcus aureus-induced but not fMLP-induced production of reactive oxygen metabolite. Moreover, although AGE albumin enhanced neutrophil phagocytosis of S. aureus, it inhibited bacterial killing. We conclude that functional RAGE is present on the plasma membrane of human neutrophils and is linked to Ca2+ and actin polymerization, and engagement of RAGE impairs neutrophil functions.
Engagement of α4β1 integrin by fibronectin induces in vitro resistance of B chronic lymphocytic leukemia cells to fludarabine
Authors: de la Fuente Mª Teresa , Casanova Benito , Moyano José V , Garcia-Gila Mercedes , Sanz Laura , Garcia-Marco José , Silva Augusto , Garcia-Pardo Angeles
Published: September 2022

B-cell chronic lymphocytic leukemia is characterized by the accumulation of malignant B lymphocytes as a result of abnormal survival signals operating in vivo. Previously, we showed that adhesion of B-CLL cells to the fibronectin fragment H89, a ligand for α4β1 integrin, prevents their spontaneous apoptosis in vitro. We have now studied whether α4β1/H89 interaction affected the response of B-CLL cells to the therapeutic drug fludarabine. B-CLL cells cultured on H89 during treatment with fludarabine showed significantly higher mean viability (P<0.05) than cells cultured on the control polylysine for all doses of drug tested. Similar results were obtained with the EHEB cell line. Analysis of the expression of Bcl-2-family proteins after 48 h of fludarabine treatment revealed that Bcl-xL levels were significantly higher (P<0.05) for cells cultured on H89 than on polylysine and correlated (r=0.56,P<0.05) with the increased cell viability observed on H89 cultures. These results indicate that Bcl-xL is involved in the survival signals induced by α4β1 ligation and may contribute to the progressive drug resistance observed in B-CLL.
Differentiation of human basophils: an overview of recent advances and pending questions
Authors: Arock Michel , Schneider Elke , Boissan Mathieu , Tricottet Viviane , Dy Michel
Published: September 2022

Basophils are rare, circulating leukocytes derived from hematopoietic CD34+ progenitors. The identification of cytokines promoting their development in vitro has led to substantial advances in understanding their differentiation process. An important role could be assigned to interleukin-3 (IL-3), which supports the maturation of hematopoietic progenitors into basophils in vitro and in vivo. In contrast to other myeloid lineages, a specific basophil growth factor has not yet been discovered. Furthermore, it is still unclear whether basophils possess a lineage-restricted progenitor or whether they share a common ancestor with mast cells (MC), eosinophils, or even megakaryocytes. Partial answers to these questions could be provided using in vitro culture systems or taking advantage of hematological disorders, such as chronic and acute myeloid leukemia (CML and AML), some myelodysplastic syndromes, and the very rare acute basophilic leukemia in which basophilic differentiation occurs.
Interferon-α as an immunotherapeutic protein
Authors: Brassard Diana L , Grace Michael J , Bordens Ronald W
Published: September 2022

Interferon-α (IFN-α) has proven to be a clinically effective antiviral and antineoplastic therapeutic drug for more than 16 years. During this time, evidence from in vitro laboratory studies and the clinical arena has supported the concept that IFN-α is an immunotherapeutic drug. By regulating a diverse set of cytokines and their receptors, IFN-α is uniquely positioned to prime the host immune response and provide an effective antineoplastic- and antiviral-immune response. IFN-α stimulates the innate cell-mediated response and then participates in the transition of the initial host innate response into an effective adaptive-immune response. IFN-α also drives the adaptive cell-mediated CD8+ T-cell response and helps to maintain a CD4+ Th1-cell population balance for an effective antineoplastic and antiviral host defense. This review will describe the current state of knowledge of IFN-α as an immunoregulatory protein and address specific issues of IFN-α as an immunotherapeutic for antineoplastic and antiviral diseases.