bluuebunny/crossref_metadata_2025 huggingface dataset:
Rat Monocytes in a Model of Combined Injury Express the OX8 Antigen
Authors: Kaffenberger W , Gruber D F , MacVittie T J
Published: January 2018

We have analyzed peripheral blood mononuclear cell preparations from a rat model of combined injury (CI) [whole-body irradiation (500 cGy 60Co) followed by a thermal injury (20% body surface area, dorsal, scald burn)] for the expression of OX8 antigens. Ficoll-separated mononuclear fractions were labeled with monoclonal antibodies MRC OX8, MRC OX19, W3/13 HLK, or W3/25 for flow cytometric analysis. Combined-injury trauma resulted in decreased mononuclear cells to 6% of normal. This effect was due to the rapid decrease in radiosensitive lymphocytes from 83% to 10%. The relative numbers of monocytes increased from a normal 13% to 70% at day 4 after CI. Labeling of cells with OX8 after CI shifted to a population which was significantly larger in volume than normal lymphocytes. At the same time the mean fluorescence intensity of OX8-positive cells was considerably reduced. With the use of a F(ab) fragment of OX8 as a probe, these results could be partially explained as unspecific binding of the whole molecule of OX8 to Fc receptors expressed by activated monocytes. But double-labeling and cell-sorting experiments also revealed the expression of OX8 antigens by a subset of OX8 + / OX19- monocytes after CI.
7C3, A Marker for the Differentiation of Human Macrophage Cell Lines
Authors: Zuckerman Steven H , Tang Julia , Gitter Bruce D , Scheetz Maurice E
Published: January 2018

The induction of differentiation in the human monoblastlike cell line U937 by 1,25 dihydroxyvitamin D3, interferon gamma, or phorbol esters is associated with the expression of a novel surface antigen, 7C3. The expression of 7C3 is maximal after 24 hr and is dependent upon de novo protein synthesis. The appearance of 7C3 during U937 differentiation is inhibited by dexamethasone while the increased expression of the macrophage marker OKM1 is not affected. 7C3 antigen is also expressed on HL60 cells when induced along the macrophage pathway and is expressed weakly on peripheral blood monocytes but not on lymphoid cells or granulocytes. 7C3 expression is sensitive to trypsin and low concentrations of the nonionic detergents NP-40 and Triton X-100. The induction of 7C3 expression may serve as a useful model to understand the regulatory events involved during the early phases of monocyte-macrophage differentiation.
Prostaglandin E2 Production by Mac-2+ Macrophages: Tumor-Induced Population Shift
Authors: Malick Adrien P , Elgert Klaus D , Garner Ronald E , Adkinson N Franklin
Published: January 2018

Tumor growth induced a shift in the phenotype of macrophages (MΦ) responsible for factor-mediated suppression of allogeneic mixed lymphocyte reactions (MLR), and the suppression by tumor-bearing host (TBH) Mac-2+ MΦ was in part due to production of prostaglandin E2 (PGE2). Thioglycollate-elicited peritoneal MΦ from normal and TBH BALB/c mice were modulated with anti-Mac-1, -2, or -3 monoclonal antibodies (mAb) or depleted with mAb plus complement and cultured in the presence or absence of indomethacin. Culture supernatants derived from mAb plus complement-depleted Mo were added to the MLR at time of initiation and showed that the suppressor phenotype shifted from Mac-3+ in the normal host to Mac-2+ in the TBH. Mac-1+ MΦ also appeared to be involved in suppression by normal host, but not TBH, MΦ. Loss of MLR suppression (increase in MLR reactivity) correlated with an increase in protein content of the culture supernatants. In an effort to explain both this relationship and the mechanism of MLR suppression, PGE2 levels of culture supernatants were determined by radioimmunoassay. Mac-1+ MΦ were involved in the regulation of PGE2 production in normal hosts, as both activation and depletion caused an increase in PGE2 production. Depletion caused a more dramatic increase in PGE2 production than did activation, suggesting that Mac-1+ MΦ had a dampening effect on PGE2 production. In contrast, no Mac-1+ MΦ-mediated regulatory function occurred in the TBH. Mac-3+ MΦ were involved in the regulation of PGE2 production in both normal and TBH. Mac-2+ MΦ were the primary producers of PGE2 in the TBH, but not in the normal host, as their depletion in the TBH caused a significant loss of PGE2 production. Thus, immunosuppression in the TBH was at least partly due to the inability of Mac-1+ and/or Mac-3+ MΦ to control production of PGE2 by Mac-2+ MΦ.
Role of the Mononuclear Phagocyte System in the Development of Acquired Immunodeficiency Syndrome (AIDS)
Authors: Roy Sophie , Wainberg Mark A
Published: January 2018

This review describes current understanding of the role of cells of the mononuclear phagocyte system in the development of acquired immunodeficiency syndrome (AIDS). Monocyte-macrophage like cells have been shown to harbor human immunodeficiency virus type 1 (HIV-I) infection in both peripheral blood and bone marrow as well as in target organs such as brain, lungs, lymph nodes, and skin. Mononuclear phagocytes that have been infected by HIV-I do not undergo significant cytopathic changes, suggesting that they may be important viral reservoirs. These and related cells may also promote the slow, persistent nature of HIV-I infections by escaping host immunologic surveillance mechanisms. There is evidence that HIV-I infections in monocytes and premonocytes can initially be latent but progress to an active viral replication state upon differentiation and/or maturation. Functional abnormalities in the mononuclear phagocyte system following infection by HIV-I have also been described, and these may be partially responsible for the severe immunosuppression characteristic of AIDS and AIDS-related disorders. These defects may be mediated by quantitative and qualitative changes in the T-helper population. Although the role of mononuclear phagocytes as viral reservoirs and as mediators of immunosuppression is still largely speculative, increasing evidence suggests that these cells influence the course of HIV-I infections.
Sources of Extracellular Lysosomal Enzymes Released in Organ-Culture by Developing and Healing Inflammatory Lesions
Authors: Kajiki Akira , Higuchi Kazuyuki , Nakamura Masahiro , Liu Louis H , Pula Peggy J , Dannenberg Arthur M
Published: January 2018

Developing and healing inflammatory lesions were topically produced in the skin of rabbits by sulfur mustard (SM). After the rabbits were sacrificed, the various lesions were removed and organ-cultured. The organ-culture fluids extracted the extracellular lysosomal enzymes (add phosphatase, β-glucuronidase, β-galactosidase, and lysozyme), so that they could be measured biochemically along with lactic dehydrogenase (LDH), an enzyme marker for cell death. In tissue sections, the number and types of cells were counted, and their lysosomal enzyme content evaluated histochemically.

The culture fluids from peak lesions contained much lower levels of all five enzymes than did culture fluids from healing lesions. When histological-histochemical-biochemical correlations were made, serum, macrophages (MN), and activated fibroblasts (but not tissue PMN) appeared to be major sources of extracellular lysosomal enzymes in peak lesions; and the dead PMN in the crusts and the activated fibroblasts in the tissues appeared to be major sources in healing lesions. The high lysosomal enzyme content of the crusts covering the lesions suggests that this passive barrier may also play an active role in promoting healing and in protecting against invasion by microorganisms.
Distinct Subpopulations of Elicited Human Macrophages in Peritoneal Dialysis Patients and Women Undergoing Laparoscopy: A Study on Peroxidatic Activity
Authors: Bos H J , van Bronswijk H , Helmerhorst T J M , Oe P L , Hoefsmit E C M , Beelen R H J
Published: January 2018

The endogenous peroxidatic activity (PA) pattern of peritoneal macrophages from 24 continuous ambulatory peritoneal dialysis (CAPD) patients and from five healthy women undergoing laparoscopy was studied. In general, the macrophages showed two different PA patterns in vivo: exudate and negative macrophages. However, two of 24 CAPD patients showed resident macrophages, the first described in vivo in man. Since, in general, the examined human peritoneal macrophages are exudate and PA-negative, this suggests, in accordance with the animal model system, that a chronic sterile inflammation exists in the peritoneal cavity of CAPD patients and healthy women undergoing laparoscopy. After 2 hr culture, blood monocytes and peritoneal macrophages transformed into cells with the characteristics of exudate-resident and resident macrophages, so isolation procedures that Include short periods of culture can change the developmental stage of human monocytes and macrophages.
Polyanionic Agents Inhibit Phagosome-Lysosome Fusion in Cultured Macrophages: A Reply to the Suggestion of Goren, Vatter, and Fiscus to the Contrary
Authors: D’Arcy Hart P , Young M R
Published: January 2018

The paper and review by Goren et al. (J. Leukocyte Biol. 41,111, 1987) contain serious objections to the reports from several laboratories on the pattern of fusion of secondary lysosomes with phagosomes (yeasts being predominantly the target) in potyanion-treated macrophages; these reports had concluded that the polyanions were inhibitors of this fusion. The main objection by Goren et al. is to the alleged misuse of electron microscopic (EM) lysosome markers; many instances of phagosome-lysosome (P-L) fusion in the treated cells have therefore been missed. The central argument is that 1) the “hydrocolloid” properties of certain of these polyanions hinder the passage of the enmeshed marker from lysosome to phagosome after their fusion and 2) this hindrance is mistakenly interpreted as indicating that fusion has not taken place, thus giving rise to the belief that the polyanions can inhibit fusion. In reply, we explain that we score as P-L fusion any instance of marker (ferritin) being seen anywhere in a fused phagosome (phagolysosome). For this crucial reason, immobilisation of marker by a hydrocolloid polyanion, e.g., in lysosomal residue of phagolysosomes or just within phagosome membranes (as in Goran’s Figs. 5 and 6 [8]), would not seriously threaten the marker distinction between fusion and nonfusion (with consequent underestimation of the former) and therefore would not invalidate the reports of a high incidence of nonfusion in potyanion-treated macrophages. Such inhibition of P-L fusion is supported by using as lysosomal label the nonpermeant fluorescent probe lucifer yellow (accepted by Goren et al. as a reliable indicator of fusion). Further support comes from the correlated inhibition of the saltatory movements of secondary lysosomes previously described; static lysosomes will have their contact with the phagosomes severely restricted. Another criticism is based on the failure of certain salient properties and functions of phagosomes to change significantly after polyanion treatment of the macrophages; these include intraphagosomal digestion, presence of lysosomal enzymes, and acidification. However, this indirect evidence can be accounted for alternatively by the operation of factors (primary lysosomes, endogenous acidification, etc.) not affected by the polyanionic block. We conclude that fusion inhibition by the polyanions is a real phenomenon, as previously reported, notwithstanding the hydrocolloid properties of some of them. Furthermore, an explanation based on hydrocolloid properties is questionable, since one or possibly two of the five main polyanionic agents appear not to be hydrocolloids.
Enrichment of Dendritic Cells From Human Peripheral Blood
Authors: Räsänen Liisa , Lehto Maili , Leinikki Pauli
Published: January 2018

A simplified method is described for purification of dendritic cells from human peripheral blood. The method is based on depletion of phagocytes with carbonyl iron and magnet, followed by centrifugation of nonphagocytic cells on Percoll and elimination of contaminating T lymphocytes, B lymphocytes, natural killer cells, and monocytes from the low-density cell fraction by treatment with monoclonal antibodies and complement. The purity of enriched dendritic cells was about 80% and these cells represented 0.2% of the starting mononuclear cell population. Dendritic cells were potent autologous and allogeneic stimulators in mixed leukocyte cultures.
Heterogeneity of Macrophages Evidenced by Variability in Their Glycoconjugates
Authors: Tsukada M , Spicer S S
Published: January 2018

Staining rat tissues with a battery of 15 lectin-horseradish peroxidase conjugates showed that macrophages contain glycoconjugates possessing terminal α, β-galactose, N-acetylgalactosamine, fucose, and N-acetylneuraminic acid, plus two terminal disaccharides. Dissimilar binding of lectins by different phagocyte populations in the same or different organs evidenced variability in glycoconjugates according to the location of the macrophages. With a group of four lectins, macrophages stained most intensely in lung, next strongest in splenic red pulp and lymph node sinuses, and weakest in skin and liver. Two populations of macrophages were newly recognized in spleen on the basis of content of fucose-rich glycoconjugate. These included a necklace-like band of macrophages at the border between marginal zone and germinal center and distinctive macrophages dispersed throughout the marginal zone. In lymph nodes, phagocytes stained strongly in the germinal centers and weakly in sinuses for glycoconjugate with N-linked oligosaccharides and conversely for glycoconjugate with terminal β-galactose. Variable lectin binding indicated heterogeneity of thymic macrophages. Lectin cytochemistry offers increased sensitivity for detecting macrophages in tissue sections, provides selective staining that shows the prevalence and distribution of the phagocytes and differentiates macrophages into separate subtypes.
Human Alveolar Macrophage Function: Differences Between Smokers and Nonsmokers
Authors: Thomassen Mary Jane , Barna Barbara P , Wiedemann Herbert P , Farmer Mark , Ahmad Muzaffar
Published: January 2018

Human alveolar macrophages and peripheral blood monocytes were obtained from smoking and nonsmoking normal volunteers. The macrophages and monocytes were incubated in vitro with bacterial lipopolysaccaride (LPS). The oxidative metabolic response of these cells was measured by superoxide anion production. Macrophages from smokers were suppressed in their superoxide anion response to LPS activation as compared to macrophages from nonsmokers. Monocytes from smokers and nonsmokers were not different. The cytotoxic properties of these macrophages and monocytes were assessed by an in vitro 3H-thymidine release assay against various allogeneic target cells. Macrophages and monocytes exposed to LPS were rendered tumoricidal. Macrophages from nonsmokers appeared to generate greater cytotoxic activity than macrophages from smokers. Macrophages from both smokers and nonsmokers were cytotoxic for three different tumorigenic cell lines but not for a nontumorigenic cell line. Monocytes from smokers and nonsmokers were not different in cytotoxic activity. We conclude that macrophages from both smokers and nonsmokers can be activated after exposure to LPS; however, macrophages from smokers may be slightly suppressed in their responses.
Interferon-lnduced Indoleamine 2,3-Dioxygenase Activity in Human Mononuclear Phagocytes
Authors: Carlin Joseph M , Borden Ernest C , Sondel Paul M , Byrne Gerald I
Published: January 2018

Interferon (IFN)-induced tryptophan degradation, catalyzed by indoleamine 2,3-dioxygenase (IDO), has been shown to mediate antimicrobial activity in epithelial cells. IDO activity has also been augmented in peripheral blood mononuclear cells (PBMC) treated with IFN or interleukin-2 (IL-2). The effector cells in this population have now been further characterized. PBMCs were isolated from normal donors, separated into monocyte and lymphocyte populations by plastic adherence, treated with IFN or IL-2, and cultivated in medium supplemented with [3H]tryptophan. Culture supernatants were collected after a 48-h incubation and fractionated by high-performance liquid chromatography; radioactivity was determined in fractions corresponding to tryptophan and its metabolites. IFN-γ and IFN-β induced IDO activity only in monocytes (plastic-adherent, nonspecific esterase-positive PBMCs). The induction of IDO activity by IL-2 required both monocytes and lymphocytes. Interaction was required between these populations for induction of IDO by IL-2, due to production of IFN-γ by T lymphocytes, with subsequent IFN-γ-mediated induction of IDO in monocytes. A number of myeloid cell lines as well as monocyte-derived macrophages were also tested for their ability to be induced to degrade tryptophan in response to IFN treatment. Monocyte-derived macrophages were found to retain their capacity to be induced by IFN-γ and IFN-β to degrade tryptophan after differentiation, and to possess seven times more IDO activity per cell than IFN-induced monocytes. However, the presence of lipopolysaccharide (LPS) in the culture medium was required for the maximum induction of IDO activity by IFN-β. Furthermore, higher concentrations of LPS were sufficient to induce IDO activity in macrophages in the absence of exogenous IFN.
Capacities of a Newly Established Thymic Stromal Cell Clone to Express la Antigens and to Produce Interleukin-6, Colony-Stimulating Factor, and Thymic Stroma-Derived T-Cell Growth Factor
Authors: Ogata Masato , Matsubara Hidetoshi , Takai Yasuyuki , Kosaka Hiroshi , Katagiri Tatsuo , Sano Haruo , Ishimura Kazunori , Fujita Hisao , Hamaoka Toshiyuki , Fujiwara Hiromi
Published: January 2018

Thymic stromal cell lines, termed MRL104 and MRL28, have been isolated from long-term liquid cultures of thymic stromal cells from MRL/1 mice. The capacities of these parental lines and derived clones to express la antigens and to produce cytokines involved in T-cell proliferation and/or differentiation were investigated. Parental lines and their clones did not exhibit a typical fibroblastic, macrophage-like, or epithelial appearance in electron as well as phase-contrast micrographs. These thymic stromal cells seemed to differ from established fibroblast lines in that these thymic stromal cells expressed la antigens after exposure to interferon-γ (IFN-γ), whereas fibroblast lines did not They also appeared to differ from macrophage cell lines in that they lacked the expression of Mac-1 antigens on their cell surface and produced no detectable level of interteukin-1 (IL1) before or even after exposure to lipopolysaccharide. When these parental lines and its clones were tested for their ability to produce various types of cytokines, it was revealed that they were capable of producing colony-stimulating factor (CSF), IL6, and thymic stroma-derived T cell growth factor (TSTGF). which was recently described, but were unable to generate other lymphokines and IFNs. Thus these cell lines and clones represent unique features in that they have potentials to express la antigens and to produce CSF, IL6, and TSTGF. The biological significance for the expression of these features is discussed in the context of intrathymic T-cell maturation and T-cell repertoire selection.
Oxidative Responses of Rabbit Alveolar Macrophages: Comparative Priming Activities of MIF/MAF, Sera, and Serum Components
Authors: Hayakawa Hiroshi , Umehara Keiko , Myrvik Quentin N
Published: January 2018

The comparative abilities of various reagents to prime rabbit alveolar macrophages (AM) to produce reactive oxygen intermediates (ROI) in a chemiluminescent (CL) assay were investigated. It was noted that AM from normal rabbits cultured in a serum-free medium for 18 hr exhibited a “spontaneous” priming response following a challenge with phorbol myristate acetate (PMA); however, “spontaneous” priming was not evident when the AM were cultured for only 3 hr. It was further established that pretreatment of normal AM for 3 or 18 hr with MIF/MAF preparations (serum-free), fetal bovine serum (FBS), or bovine serum albumin (BSA) exhibited marked increases in their CL reponses following challenge with PMA. When FBS was used in the culture medium, the priming activity of MIF/MAF was masked because of the high CL responses of controls due to the priming effects of FBS. BSA at concentrations approximately equivalent to the amount in FBS also displayed marked priming activity. Bacterial products (lipopolysaccharide and muramyl dipeptide), latex particles, rabbit IgG, PMA, and opsonized as well as nonopsonized zymosan and bacteria (BCG and Staphylococcus epidermidis) were inactive as priming agents. In comparison, AM from BCG-immune rabbits that were primed in vivo yielded a very large CL response when challenged with PMA. Opsonized zymosan and bacteria produced twofold increases in the CL responses in BCG-immune AM compared to nonopsonized preparations. The marked priming effect of serum on AM cultured for even a short period (3 hr) indicates that normal AM undergo marked changes in culture that complicate the interpretation of AM function when AM are cultured in vitro in media containing serum.
Interactions of Pseudorabies Virus With Swine Alveolar Macrophages: Effects of Virus Infection on Cell Functions
Authors: Iglesias Gerardo , Pijoan Carlos , Molitor Thomas
Published: January 2018

In order to assess the effect of Pseudorabies virus (PRV) infection on the function of swine alveolar macrophages (AM), lung lavage cells were cultured, infected with one of six strains of PRV, and various activities were measured. Activity measurement included viability, phagocytosis of yeast, phagosome-lysosome fusion, phagocytosis of opsonized particles, and superoxide release. AM were infected with 5 × 10-3 PFU/cell, and the comparative assessment of functions was performed at 18-20 h postinfection. Cell viability in PRV-infected cultures ranged from 79 to 94% of the viability in noninfected cultures. Phagocytosis of yeast was significantly reduced only in the AM cultures infected with the strain S-62. Phagosome-lysosome fusion was depressed in cultures infected with the strains S-62, 4892, 3816, and BUK. The phagocytosis of opsonized sheep red blood cells showed significant differences between noninfected and PRV-infected cultures in all cases except cultures infected with the strain PRV-C. The O2 release after stimulation with opsonized zymosan was significantly reduced in all the PRV-infected cultures. The effect of PRV infection on AM functions that are related to the bacterial activity of such cells suggests that PRV-induced AM dysfunction might have a role in the increased susceptibility of PRV-infected pigs to bacterial pneumonia.
Separation of Potent and Poorly Functional Human Lung Accessory Cells Based on Autofluorescence
Authors: Nicod Laurent P , Lipscomb Mary F , Toews Galen B , Weissler Jonathan C
Published: January 2018

Human alveolar macrophages obtained by bronchoalveolar lavage are usually poor accessory cells in in vitro lymphoprollferation assays. However, we recently described a subpopulation of pulmonary mononuclear cells, obtained from minced and enzyme-digested lung, which were potent stimulators of allogeneic T-lymphocyte proliferation. These cells were enriched in loosely adherent mononuclear cell (LAM) fractions, but further study of these accessory cells was hampered by the heterogeneous nature of LAM. It was observed that in the majority of lung tissue sections, most alveolar macrophages were autofluorescent, whereas most interstitial HLA-DR positive cells were not. Therefore autofluorescence was utilized to fractionate LAM in an attempt to remove alveolar macrophages and selectively purify interstitial accessory cells. LAM were separated by flow cytometry using forward and side scatter to exclude lymphocytes, and red autofluorescence to obtain brightly autofluorescent (A pos) and relatively nonautofluorescent (A neg) mononuclear cells. Although both populations contained over 80% HLA-DR positive cells, A pos cells were poor accessory cells, whereas A neg cells were extremely potent stimulators of a mixed leukocyte reaction at all stimulator ratios tested. When A pos cells were added to A neg cells, T-cell proliferation was markedly suppressed in the majority of experiments. Morphologically, A pos cells appeared similar to classical alveolar macrophages with 95% of the cells being large and intensely nonspecific esterase positive. In contrast, the majority of A neg were smaller, B-cell antigen-negative, nonspecific esterase negative, and had a distinctive morphology on Wright-stained smears. We conclude that fractionation of LAM based on autofluorescence is a powerful tool to isolate and characterize lung mononuclear cells that act either as stimulators or as suppressors of immune responses in the lung.
Characteristics of Monocyte Angiotensin-Converting Enzyme (ACE) Induction by Dexamethasone
Authors: Vuk-Pavlović Zvezdana , Kreofsky Teresa J , Rohrbach Michael S
Published: January 2018

Monocyte maturation to macrophages and transformation into epithelioid granuloma cells in some granulomatous diseases are accompanied by the induction of membrane-bound angiotensin-converting enzyme (ACE). The physiologic and pathophysiologic roles of ACE generated in these processes are not known. The pattern and the mechanism of ACE induction in human monocytes are also not well understood. Dexamethasone is one of the agents reported to induce elevated ACE activity in human monocytes, and therefore a suitable tool for studying the phenomenon. This study shows that dexamethasone augments monocyte ACE in a Diphasic dose-dependent manner with maximum effect at 10-5 M concentration. Although it enhances the level of ACE activity, dexamethasone doss not alter the time course for ACE induction from that found in unstimulated monocytes. The ACE activity of monocytes cultivated in 10 nM dexamethasone and then exposed to 10-3 M diazosulfanilic acid (DASA) is reduced approximately by 80% in comparison with cells not treated with DASA, demonstrating that dexamethasone-induced ACE is an ectoenzyme. Dexamethasone does not increase the activity of other monocyte ectoenzymes: γ-glutamyltransferase, alkaline phosphodiesterase-I, and leucine aminopeptktase, showing that dexamethasone induction of ACE is a specific, rather than generalized, effect on plasma membrane enzymes. It is suggested that the increase in ACE activity is due to the increased rate of enzyme synthesis.
Lithium Chloride Stimulates Human Monocytes to Secrete Tumor Necrosis Factor/Cachectin
Authors: Kleinerman Eugenie S , Knowles Rebecca D , Blick Mark B , Zwelling Leonard A
Published: January 2018

The purpose of this study was to examine the effect of lithium chloride (LiCI) on human monocytes. Patients undergoing lithium therapy have elevated white blood cell counts. Since both tumor necrosis factor alpha (TNFα) and interleukin 1 (IL-1), which are secreted by monocytes, can stimulate endothelial cells to produce granulocyte-macrophage colony-stimulating factor (GM-CSF), we determined whether lithium-stimulated monocytes produced TNFα and/or IL-1. Normal human monocytes were incubated for 24 h with medium (negative control), lipopolysaccharide (positive control), or LiCI (0.05–50 mM). The supernatants were removed and assayed for IL-1 and TNFα secretion using the D10.G4.01 and L929 assays, respectively. Lithium did not stimulate IL-1 secretion but did stimulate TNFα secretion (5–10 U/ml of TNFα per 2 x 105 monocytes). The increased secretion of TNFα was associated with a fourfold increase in TNFα mRNA. TNFα activity in the supernatants was neutralized by a monoclonal antibody against human TNFα but not by antibody against human albumin. Other alkali metals such as rubidium and cesium did not stimulate monocytes to secrete TNFα. These data indicate that one mechanism by which Li may cause granulocytosis is through a transcriptional enhancement of TNF production and subsequent secretion by monocytes.
Role of C5a in the Induction of Tumoricidal Activity in C3H/HeJ (Lps
d) and C3H/OuJ (Lps
n) Macrophages
Authors: Hogan M Michele , Yancey Kim B , Vogel Stefanie N
Published: January 2018

Thioglycollate-elicited macrophages from C3H/HeJ (Lpsd) and C3H/OuJ (Lpsn) mice were cultured in a two-signal, tumoricidal assay using recombinant interferon-γ (rlFN-γ) as the “priming” signal and recombinant human C5a (rC5a) as the “trigger” signal. These experiments were compared directly with a well established, two-signal tumoricidal assay in which rlFN-γ was used as the “priming” signal and protein-rich, butanol-extracted lipopolysaccharide (But-LPS) as the “trigger” signal. These studies showed that rlFN-γ-primed macrophages can be triggered in a dose-dependent manner by rC5a to effecthigh levels of tumoricidal activity. Maximum levels of cytotoxicity achieved using this endogenously produced, biologically active peptide as a “trigger” signal were comparable to those obtained using But-LPS. Moreover, experiments in which anti-C5 antibody was included in macrophage cultures stimulated with rlFN-γ and But-LPS showed a significant reduction (P < .05) in tumoricidal activity. Because LPS has been shown to induce macrophage C5 production and enzyme release, these findings suggest that macrophage-derived C5 is locally converted to C5a (or some other biologically active C5 cleavage fragment), which functions as an autocrine trigger signal for the induction of tumoricidal activity. In summary, these data suggest 1) that rC5a can provide a “second signal” to rlFN-γ-primed murine macrophages for the induction of tumoricidal activity and 2) that macrophage-derived C5 or C5a may represent an autocrine signal induced by exogenous “trigger signals.”
Natural Killer Cell Activity and Macrophage-Dependent Inhibition of Growth or Killing of Mycobacterium avium Complex in a Mouse Model
Authors: Bermudez Luiz Eduardo M , Kolonoski Peter , Young Lowell S
Published: January 2018

Natural killer (NK) cells from spleens of normal and Mycobacterium avium complex (MAC)-infected C57 black mice (C57 BL/6 bg/+) were examined for their capacity to activate splenic and peritoneal macrophages from beige mice to inhibit or kill intracellular MAC. Peritoneal and splenic macrophages from beige mice were exposed in vitro to NK cells obtained from MAC-infected and uninfected black mice. NK cells from uninfected black mice were also treated in vitro with recombinant interleukin-2 (IL-2) for 48 h before incubation with macrophages. While control macrophages supported intracellular growth of MAC, macrophages exposed to unactivated NK cells inhibited growth of the intracellular bacteria, as determined 4 days after infection. IL-2 stimulated NK cells, and NK cells obtained from MAC-infected animals were able to activate murine macrophages in vitro to inhibit growth or kill 40.0 ± 5% and 61.3 ± 6% of the intracellular bacteria, respectively. In other experiments, beige mice (C57 BL/6 bg/bg) were treated intraperito-neally with NK cells obtained from MAC-infected and uninfected C57 black mice. Peritoneal macrophages harvested from beige mice treated with NK cells activated in vitro with IL-2 killed 24.4 ± 4% of intracellular bacteria by day 4 after infection. Macrophages obtained from animals treated with NK cells harvested from MAC-infected black mice killed 58.8 ± 7% of intracellular bacteria by 4 days after infection, in contrast with intracellular growth observed in macrophages obtained from untreated animals and from animals treated with Hanks' solution or unactivated NK cells. These crossover studies suggest that NK cells may be important in host defense against MAC.
Surface Phenotype Analysis of Human Monocyte to Macrophage Maturation
Authors: Andreesen Reinhard , Brugger Wolfram , Scheibenbogen Carmen , Kreutz Marina , Leser Hans-Georg , Rehm Annegret , Löhr Georg W
Published: January 2018

Cells of the mononuclear phagocyte system arise from circulating blood monocytes. Upon emigration from the vasculature, monocytes differentiate into macrophages, a process that monocytes similarly undergo in vitro. We have established primary cultures from elutriated or adherence-purified blood monocytes and analyzed the antigenic modulation during monocyte to macrophage transformation, which could be followed by the expression of specific antigens and which required as yet unknown inducer signals present in the serum. It is shown that in the absence of serum monocytes only survive in vitro when cultured adherent to plastic but rapidly die in suspension culture. Starting at 0.5%, serum induced maturation dose-dependently, with the optimal concentration being 2 to 5%. Of those antigens not present on monocyte, the low-affinity Fc receptor (CD16), the α-chain of the vitronectin receptor (CD51), gp65-MAX.1, and gp68-MAX.3 were expressed only upon serum-induced macrophage differentiation, whereas the transferrin receptor (CD71), MAX.26, and to some degree also gp65-MAX.11 appeared to be independent of maturation and were also found on primary cultures of adherent monocytes under serum-free conditions. In addition, the rapid induction of HLA class II antigens (within 24 hr) was similar with and without serum, as was the continued high-density expression in long-term culture. The monocyte-specific CD14 antigen was down-regulated in the absence of serum but kept its level of expression on differentiated macrophages. In comparison, alveolar and peritoneal macrophages, respectively, differed in their antigenic phenotype: Alveolar macrophages expressed high HLA class II antigens but low CD14, whereas for peritoneal macrophages the opposite was found. Both interferon-γ and -α suppressed macrophage maturation in vitro but had contrary effects on HLA class II and CD16 expression: Interferon-γ up-regulated the two types of antigens, which, in contrast, were down-regulated by interferon-α.
Relationship of Chemotactic Receptors for Formyl Peptide and C5a to CR1, CR3, and Fc Receptors on Human Neutrophils
Authors: Van Epps D E , Bender J G , Simpson S J , Chenoweth D E
Published: January 2018

The co-expression of C5a and formyl-methionine-leucine-phenylalanine-lysine (FMLPL) receptors with CR1, CR3, and Fc receptors on human neutrophils (PMN) was studied. Fluorescein-conjugated C5a (FL-C5a) and FMLPL (FL-FMLPL) were used to identify C5a and formyl peptide receptors. CR1, CR3, and Fc receptors were identified with monoclonal antibodies and a Texas red-labeled goat anti-mouse immunoglobulin second step reagent The co-expression of chemotactic receptors with CR1, CR3, or Fc receptors was evaluated using two-color flow cytometry. A direct correlation between the degree of expression of receptors for FL-FMLPL and the expression of CR3, CR1, and Fc receptors on individual PMN was observed. In contrast, no correlation between the degree of C5a receptor expression and CR1, CR3, or Fc receptor expression was found. Similar results were obtained with PMN after up regulation of CR1, CR3, Fc, and FMLPL receptors by incubation at 37°C for 10 min with or without phorbol myristate acetate. These data suggest that the expression of FMLPL, CR1, CR3, and Fc receptors are regulated in a similar manner, whereas C5a receptor expression is regulated independently. Furthermore, these data indicate that within a given population of PMN, a parallel exists between the degree of CR1, CR3, FMLPL, and Fc receptor expression on individual cells.
Cytoplasmic Components of Natural Killer Cells Limit the Growth of Cryptococcus neoformans
Authors: Hidore Michelle R , Nabavi Nasrin , Reynolds Craig W , Henkart Pierre A , Murphy Juneann W
Published: January 2018

Murine natural killer (NK) cell-mediated inhibition of growth of a yeast-like target cell, Cryptococcus neoformans, was completely abrogated by blocking the effector cell secretory process with monensin. Therefore, further studies were performed to determine the ability of various cytoplasmic fractions of NK cells to mediate inhibition of cryptococcal growth. Percoll-fractionated homogenates of rat LGL tumor cells demonstrated that the granule-containing fractions plus three additional sets of less dense cytoplasmic fractions displayed anti-cryptococcal activity; whereas only the cytoplasmic granule-containing fractions had cytotoxic activity against YAC-1 tumor cell and sheep erythrocyte targets. Maximal cryptococcal growth inhibition induced by LGL granules occurred after a 1 h incubation, required the presence of Ca2+ (1.0 mM) or Mg2+ (0.5 mM or 5.0 mM), and was completely abrogated in the presence of rabbit anti-LGL granule IgG. Cytolysin, the granule component which mediates tumor cell and sheep erythrocyte lysis, effectively limited the growth of cryptococci. Since Percoll gradient fractionation of the LGL homogenates demonstrated three separate peaks of anti-cryptococcal activity other than the granule peak, it is possible that the cytolysin-containing granules are not the only subcellular component of NK cells playing a role in inhibition of C. neoformans growth.
Thromboxane Release by Lymphokine-Differentiated U937 Human Monocytic Cells: Response to Platelet-Activating Factor (PAF) and Chemotactic Peptide (FMLP) but Not to Low Affinity IGE-Receptor (FcεRII/CD23) Occupation
Authors: Storch Joachim , Edwards Robert J , MacDermot John
Published: January 2018

The primary objective of this study was to explore if the CD23 antigen is a functional low affinity IgE receptor on macrophages for the release of thromboxane B2 (TXB2). The responsiveness of U937 monocytic cells and their macrophage-like inducible forms to platelet-activating factor (Paf), the chemotactic peptide fMLP, and low affinity IgE-receptor occupation was examined. Differentiation of U937 cells by phorbol myristate acetate (PMA) and a cancer cell line (HBT 5637) conditioned medium (5637-CM), but not INFg or IL4, resulted in a macrophage-like cell line which released TXB2. A high basal release of TXB2 with no significant response to Paf or fMLP challenge was seen following culture of cells with PMA. In 5637-CM-differentiated cells, Paf and fMLP induced a rapid release of TXB2, about 10 fold above basal activity. There was a slow Ca-Independent response to short-term treatment with PMA and a rapid Ca-dependent response to the ionophore A23187. Both stimulants acted synergistically on TXB2 synthesis in 5637-CM differentiated cells. Although low affinity receptors for IgE (FcεRII/CD23) were induced by 5637-CM, no TXB2 was released in response to soluble or latex-bound IgE-antigen complexes or to anti-FcεRII/CD23-antibodies. IL4 and to a lesser extent INFg both induced FcεRII/CD23 receptor expression, but inhibited release of TXB2 in response to Paf, fMLP, or PMA. We conclude that the functional receptors for IgE on mature macrophages are most probably not FcεRII/CD23.
Flow Cytometric Study of the Activation of Polymorphonuclear Cells
Authors: Belloc Francis , Vincendeau Philippe , Freyburger Geneviève , Dumain Patrice , Boisseau Michel R
Published: January 2018

The activation of human polymorphonuclear cells (PMN) by the chemotactic peptide, N-formyl-methionyl-leucyl-phenylalanine (FMLP), or the protein kinase C activator, phorbol myristate acetate (PMA), was studied using flow cytometry. Two probes were used to evaluate PMN activation: 1) a monoclonal antibody (MoF11) directed against an antigen (Ag) expressed on the membrane of monocytes and of activated PMN; 2) rhodamine phalloidin was used at the cytoplasmic level to measure the F-actin content. The expression of MoF11 antigen was found to be 3 to 5 times greater on the membrane of PMN activated by either FMLP or PMN as compared with membrane expression of the same Ag on resting PMN. This increase was found to be dose dependent for the two activators. Kinetic studies showed that a maximum response was observed in 1 to 2 min at 37° when FMLP was used, whilst a similar response required 10 min when PMA was used. The same discrepancy with activators was observed when actin polymerization was measured by labelling with rhodamine phalloidin. However, pretreatment of PMN with cytochalasin B inhibited actin polymerization whilst MoF11 antigen expression was increased, suggesting that the MoF11 antigen could be stored in granules of resting PMN. The study of actin polymerization and of MoF11 antigen expression, separately or in combination, could be a useful tool for the detection of activated PMN in biological samples.
Interactions Between Epithelial Cells and T Lymphocytes: Role of Adhesion Molecules
Authors: Singer Kay H
Published: January 2018

Cell-cell interaction is critical for normal T cell development and function. A number of adhesion molecules important in T cell interactions with other cell types have been defined. This paper reviews the role of two adhesion pathways, CD2/LFA-3 and LFA-1/ICAM-1, in T cell interactions with epithelial cells of the thymus and skin. While thymic epithelium-T cell interactions are mediated by both the LFA-1/ICAM-1 pathway and the CD2/LFA-3 pathway, epidermal-T cell interactions are mediated primarily by the LFA-1/ICAM-1 pathway. Although ICAM-1 is not expressed in vivo on epidermal keratinocytes in normal skin, ICAM-1 is expressed by epidermal keratinocytes at the site of T cell infiltration in inflammatory dermatitis. ICAM-1 is expressed in vivo on thymic epithelium. These antigen independent adhesion molecules play an important role in the cell-cell interactions associated with T cell differentiation and function.
Gene Regulation in Macrophage Activation: Differential Regulation of Genes Encoding for Tumor Necrosis Factor, Interleukin-1, JE, and KC by interferon-γ and Lipopolysaccharide
Authors: Yu Sheau-Fung , Koerner T J , Adams Dolph O
Published: January 2018

Although macrophage activation is induced in a complex manner by signals such as Interferon-γ(IFNγ) and bacterial lipopolysaccharide (LPS) and depends on alterations in levels of specific proteins due to differences in gene expression, the complexity of gene regulation during macrophage activation in regard to multiple signals is not fully appreciated. To probe this question, we selected four model genes encoding for tumor necrosis factor (TNF), interleukin-1 (IL-1), and the immediate early genes JE and KC. After analyses of Northern blots for specific mRNA, LPS was found to enhance levels of mRNA for IL-1, TNF, JE, and KC. IFNγ initialed heightened mRNA levels for JE but did not alter specific mRNA for IL-1, TNF, or KC. When IFNγ and LPS were combined, additive effects on levels of specific mRNA for JE, enhancement of mRNA for TNF, suppressed mRNA for KC, and no effect on mRNA for IL-1 were observed. When transcription of these genes was assessed by nuclear “run on” experiments, LPS increased transcription of KC and TNF but not of IL-1 or JE, implying that the increased levels of mRNA for JE and IL-1 were attributable to increased stability of mRNA. Likewise, IFNγ did not initiate transcription of JE. When IFNγ and LPS were given together, IFNγ enhanced the LPS-induced transcription of TNF and KC, suggesting decreased stability of mRNA for KC. A distinct pattern of regulation for each of the four genes was thus observed. Taken together, the data suggest that gene regulation in macrophage activation represents a complex response of enhanced and suppressed transcription and mRNA stability, the precise pattern of which depends on the stimuli given to the macrophages and the gene examined.
Relationship Between Chemical Composition and Biological Function of Pseudomonas aeruginosa Lipopolysaccharide: Effect on Human Neutrophil Chemotaxis and Oxidative Burst
Authors: Kharazmi Arsalan , Fomsgaard Anders , Conrad Robert S , Galanos Chris , Høiby Niels
Published: January 2018

There are conflicting data on the effect of bacterial lipopolysaccharides (LPS) on the function of human neutrophils. The present study was designed to examine the relationship between chemical composition and the modulatory effect of LPS on human neutrohpil function. LPS was extracted from five strains of Pseudomonas aeruginosa isolated from cystic fibrosis patients by the hot phenol–water method. Chemical characterization included neutral sugars, amino components, and fatty acids. Neutrophils isolated from peripheral blood of healthy individuals were preincubated with different concentrations of LPS. After preincubation, the chemotaxis and chemiluminescence of neutrophils to various stimuli were determined. It was shown that LPS from different strains did not exert the same degree of regulatory effect on neutrophil functions. LPS from strain 174-O:9 exerted the most pronounced effect on neutrophil function seen as inhibition of neutrophil chemotaxis toward the chemotactic peptide f-Met-Leu-Phe and zymosan-activated serum (ZAS) and priming of the cells for ≤8-fold enhancement of chemiluminescence response to f-Met-Leu-Phe. Conversely, LPS from strain 1118-O:3 had no effect on neutrophil chemotaxis and a slight effect on chemiluminescence. The major differences in chemical composition of the LPS from these two strains are in the rhamnose and heptose content of the O side chain and in the alanine content of the core region. These data indicate that chemical composition of the LPS molecule may play an important role in biological activity of LPS.
Priming and Stimulation of Bovine Neutrophils by Recombinant Human interleukin-1 Alpha and Tumor Necrosis Factor Alpha
Authors: Sample Allen K , Czuprynski Charles J
Published: January 2018

We have examined the in vitro effects of two recombinant human monokines, interleukin-1 alpha (rHulL-1α) and tumor necrosis factor alpha (rHuTNFα), on bovine neutrophil functions. Both rHulL-1α (10 to 1,000 ng/ml) and rHuTNFα (5 to 50 ng/ml) directly stimulated the oxidative burst of bovine neutrophils as measured by Luminol-dependent chemiluminescence, superoxide anion generation, and hydrogen peroxide production. In addition, both rHulL-1α (1 to 1,000 ng/ml) and rHuTNFα (0.5 to 50 ng/ml) primed bovine neutrophils for an enhanced oxidative burst to subsequent stimulation with opsonized zymosan. Neutrophils pretreated with either monokine exhibited an earlier, as well as stronger, zymosan-stimulated Luminol-dependent chemiluminescence response, as compared to untreated neutrophils. Exposure of bovine neutrophils to combinations of suboptimal doses of rHulL-1α (10 and 100 ng/ml) and rHuTNFα (0.5 and 5 ng/ml) resulted in a synergistic stimulation of Luminol-dependent chemiluminescence, whereas, no synergism was observed when using optimal doses of each monokine. Pre-incubation of bovine neutrophils with an optimal concentration of recombinant bovine interferon gamma (100 U/ml), and either rHulL-1α or rHuTNFα further augmented the maximal oxidative response of neutrophils stimulated with opsonized zymosan. Bovine neutrophils released both primary and secondary granules in response to rHulL-1α and rHuTNFα, and also exhibited enhanced adherence in the presence of either monokine.