摘要:

AbstractSites of cutaneous infection withLeishmania majorin genetically susceptible (BALB/c) and resistant (C57B1/6) mice were investigated for the early inflammatory response (6 h to 12 days) by electron microscopy combined with enzyme‐histochemical methods. Susceptible BALB/c mice spontaneously recruited only polymorphonuclear leukocytes (PMNs) at the site of infection. Infiltrating mononuclear phagocytes (and eosinophils) were first observed at day 1 in a ratio equal to the influx of PMNs (about 40%). This pattern persisted during the following 11 days of infection. In the resistant C57/B16 mice, the first cellular infiltrate at the infected site contained mononuclear phagocytes (25%) and eosinophils (15%) besides PMNs (60%). Within 3 days after infection, mononuclear phagocytes became the dominant population of cells in cutaneous lesions (up to 80%). It was found in situ thatL. majoraccumulated and replicated in immature macrophages, that is, intermediate stages between monocytes and resident macrophages, which were found in lesions of both strains. The burden of parasites was, however, degraded more rapidly by the infiltrating cells of the resistant mice than by those of the susceptible ones. Within the first 4 days of infection, the parasites were found in PMNs, mononuclear phagocytes, and extracellular spaces in both strains. In susceptible mice this distribution pattern persisted up to 12 days after infection; in resistant C57B1/6 mice parasites accumulated inside mononuclear phagocytes within this period. It is concluded that the features of acute inflammation during leishmaniasis in BALB/c mice are sustained over a prolonged period that is ineffective in the elimination ofL. major.

ISSN:0741-5400    

DOI:10.1002/jlb.52.2.135

出版商:Wiley    

年代:1992

数据来源: WILEY

摘要:

AbstractA simple, precise method has been developed for assessing neutrophil secretory responses (release of vitamin B12binding protein from specific granules) to challenge of aliquots of whole blood with the bacterial chemotactic peptideN‐formylmethionyl‐leucyl‐phenylalanine (fMLP). Dose‐response studies performed on blood from normal healthy volunteers showed higher maximal secretory responses in males than females (33.3 ± SEM 2.2 vs. 27.4 ± 2.5,P<.005) a left shift in dose‐response curves after feeding compared to fasting (P<.005), spontaneous up‐regulation of responses in blood incubated at 37° for 1 h, and marked up‐regulation in response to preincubation with endotoxin. This whole blood challenge method may be used to study neutrophil responses in groups of individuals or patients without the confounding effects of changes in cell responses resulting from cell isolation procedures. The method may also be used as a bioassay for neutrophil‐activating factors.

ISSN:0741-5400    

DOI:10.1002/jlb.52.2.143

出版商:Wiley    

年代:1992

数据来源: WILEY

摘要:

AbstractLeukocyte activation is known to involve cell membrane potential changes. Phenobarbital, an anesthetic and anticonvulsant that can inhibit neuronal membrane depolarization, may also affect leukocyte activation. Measuring membrane potential, actin polymerization, chemotaxis, superoxide production, lymphocyte proliferation, intracellular calcium concentration, and cytokine production, we found that phenobarbital at a concentration of 15–30 μg/ml, which is considered a therapeutic serum level for controlling seizures, did not affect polymorphonuclear neutrophil (PMN) activation. At levels higher than 100 μg/ml, phenobarbital significantly suppressed formylmethionyl‐leucyl‐phenylalanine (fMLP)‐induced chemotaxis. Concentrations greater than 300 μg/ml also inhibited phorbol myristate acetate–stimulated membrane potential change. In contrast, 30 fig/ml phenobarbital significantly inhibited lymphocyte proliferation stimulated by phytohemagglutinin (PHA) and pokeweed mitogen. This concentration of phenobarbital also suppressed the increase of intracellular free calcium induced by PHA. However, only a higher concentration of phenobarbital (300 μg/ml) was able to inhibit PHA‐induced interleukin‐2 (IL‐2) production and suppress the proliferation of PHA‐induced IL‐2 receptor–bearing lymphocytes. These results suggest that concentrations of phenobarbital associated with anticonvulsive levels do not affect PMN activation but suppress lymphocyte activation, possibly by affecting intracellular signal transduction.

ISSN:0741-5400    

DOI:10.1002/jlb.52.2.151

出版商:Wiley    

年代:1992

数据来源: WILEY

摘要:

AbstractImpairments in the respiratory burst and stimulus‐response coupling were studied with respect to the increased rate of cell replication that occurred in HL60 cells during repetitive passages in cell culture. During a 45‐week period of culture, HL60 cells developed a progressive increase in rate of replication. Concomitantly, undifferentiated cells developed an impairment in ATP‐induced calcium mobilization. The percentage of cells that could be differentiated with dimethyl sulfoxide progressively diminished. Differentiated cells developed an impairment in both the respiratory burst and secretion of β‐glucuronidase. In addition, regulation of the respiratory burst by cAMP agonists including isoproterenol, adenosine, and prostaglandin E2was reduced in rapidly proliferating cells. Thus, multiple changes in stimulus‐response coupling occur during cell culture in association with an increase in rate of cell replication. It may be important to recognize progressive impairments in cell function in studies using repetitive samples of HL60 cells from a continuously maintained cell population. The observed impairments in stimulus‐response coupling may be relevant to unregulated cell growth in neoplastic disease.

ISSN:0741-5400    

DOI:10.1002/jlb.52.2.157

出版商:Wiley    

年代:1992

数据来源: WILEY

摘要:

AbstractThe transport activity of arginine in mouse peritoneal macrophages was strongly induced when they were cultured with 1 ng/ml bacterial lipopolysaccharide (LPS) for 12 h. Arginine in the medium decreased whereas ornithine in the medium increased during the culture. This time‐dependent change of arginine to ornithine was accelerated by LPS. However, the activity of arginase in the macrophages did not change during the culture with or without LPS and release of arginase from the cells to the medium was not detected. It is suggested that the transport of arginine and ornithine was a rate‐limiting step in arginine‐to‐ornithine conversion in the macrophage culture medium. A possible role of the induction of arginine transport activity in the macrophage cytocidal activity due to arginine depletion and nitric oxide production is discussed.

ISSN:0741-5400    

DOI:10.1002/jlb.52.2.161

出版商:Wiley    

年代:1992

数据来源: WILEY

摘要:

AbstractWe studied the effect of the different types of interferons on the production of cytotoxin by human peripheral blood mononuclear cells (PBMCs) stimulated with the mitogen phytohemagglutinin (PHA). Maximum secreted levels of cytotoxin were observed at day 3 in culture and consisted of both tumor necrosis factor α (TNF‐α) and lymphotoxin as determined by specific antibodies. Type I interferons (IFN‐α and IFN‐β) consistently suppressed cytotoxin production. Both TNF‐α and lymphotoxin were significantly suppressed. Mean suppression by IFN‐α and IFN‐β (1000 U/ml) was 56 and 66%, respectively, in PBMCs from 18 different donors. The suppressive effects of IFN‐α and IFN‐β on cytotoxin production were dose responsive over a range of 10 to 1000 U/ml. Type II interferon (IFN‐γ) did not have consistent significant effects. Pretreatment with IFN‐α or IFN‐β for 24 or 48 h prior to PHA stimulation also resulted in significant suppression. Supplementation with interleukin‐2 (10 U/ml) or IFN‐γ (1000 U/ml) did not overcome cytotoxin suppression by IFN‐α or IFN‐β. Cytotoxin suppression by IFN‐α and IFN‐β together appeared to be noninteractive. Suppression appeared not to be due to blockade of the cytotoxin release, since both cell‐associated cytotoxin and secreted cytotoxin were suppressed to the same level. These results demonstrated that cytotoxin and lymphotoxin production by PHA‐stimulated PBMCs could be down‐regulated by type I interferons and that there is a substantial difference between the action of type I interferons and type II interferons (IFN‐γ) in modulating the biosynthesis of cytotoxins.

ISSN:0741-5400    

DOI:10.1002/jlb.52.2.165

出版商:Wiley    

年代:1992

数据来源: WILEY

摘要:

AbstractThe human monocytic cell line U937 was used as a model system to investigate the effects of glucocorticoids on monocytic differentiation. Upon incubation with the phorbol ester 12‐O‐tetradecanoylphorbol‐13‐acetate (TPA) (5 × 10‐9M) for 48 to 72 h, the immature U937 cells ceased to proliferate and became morphologically and functionally macrophage‐like. Preincubation of the cells with glucocorticoids (dexamethasone and prednisolone, 10‐7and 10‐6M) but not progesterone (10‐6M) had marked effects: The cells remained in suspension and developed very little cell‐cell interaction. This correlated with decreased expression of the surface molecules ICAM‐1 and CD18 as determined by fluorescence‐activated cell sorter analysis. The TPA‐induced ability of the cells to release lysozyme or to generate reactive oxygen radicals (determined as reduction of nitroblue tetrazolium) was markedly reduced. The induction of cyclooxygenase activity and thus the ability to release prostanoids was almost completely abolished. Inhibition of prostanoid synthesis was also observed when the glucocorticoids were administered 24 or 48 h after TPA. The primary step of TPA induction, the activation and translocation of protein kinase C, however, was not affected by glucocorticoids as determined by activity measurements and Western blot analysis. There was no change in the subsequent TPA‐induced induction of c‐fos. The down‐regulation of the differentiation‐related oncogenes c‐mycand c‐mybwas the same in cells treated with TPA in the presence or absence of glucocorticoids. Furthermore, no significant effect of glucocorticoids on the TPA‐induced growth arrest was observed. Glucocorticoids thus interfere with TPA‐induced functions, which are typical for activated macrophages; however, they do not impair the differentiation process and concomitant growth inhibition.

ISSN:0741-5400    

DOI:10.1002/jlb.52.2.173

出版商:Wiley    

年代:1992

数据来源: WILEY

摘要:

AbstractWhen activated, polymorphonuclear leukocytes (PMNs) produce a small soluble factor, termed neutrophil‐derived secretagogue (NDS), that elicits electrogenic Cl‐secretion — the transport event responsible for hydration of mucosal surfaces. Work toward purification of this factor has been hampered by variability in activity of PMN‐derived NDS. Using a human‐derived intestinal epithelial cell line (T84) that serves as a model for studies of the regulation of electrogenic Cl‐secretion, we find that the human promyelocytic leukemia cell line HL‐60 secretes a factor with NDS‐like activity. Buffer conditioned by HL‐60 cells (107cells/ml for 1 h), when applied to T84 monolayers grown on permeable supports and analyzed by routine electrophysiological techniques, elicited a short‐circuit current (Isc) of 11.7 ± 1.02 μA/cm2. This short‐circuit current was sensitive to bumetanide, an inhibitor of the basolateral Na‐K‐2CI cotransporter, and was dependent on the presence of chloride in the assay buffers. Such data indicate that buffer conditioned by HL‐60 cells stimulates electrogenic Cl‐secretion. Like NDS, the active factor in HL‐60–conditioned buffer has a nominal molecular weight of less than 500 and was increased by activation of cells with phorbol ester.125I and86Rb efflux assays confirmed that the secretagogue released by stimulated HL‐60 cells, similar to PMN‐derived NDS, preferentially stimulates opening of Cl‐rather than K+channels in T84 cells. Lastly, release of NDS‐like bioactivity increases when HL‐60 cells are differentiated toward granulocytes compared to cells differentiated toward monocytes.

ISSN:0741-5400    

DOI:10.1002/jlb.52.2.183

出版商:Wiley    

年代:1992

数据来源: WILEY

摘要:

AbstractOur previous studies have shown that the monosaccharide α‐l‐fucose significantly enhances the cytolytic capacity of peripheral blood mononuclear leukocytes (PBMLs). To examine possible mechanisms through which fucose affects cytolytic activity, we studied the production of cytokines after α‐l‐fucose stimulation. In this report, we show that fucose induced a minor but significant augmentation of production of interleukin‐2 (IL‐2), but anti–IL‐2 antibodies did not completely inhibit fucose‐activated cytolysis. Fucose induced significantly higher secretion of TNF‐α by both lymphocytes and monocytes. The nature of the lytic molecule detected in the TNF bioassay was verified with specific neutralizing antibodies. In addition, fucose induced the accumulation of TNF‐α mRNA in a time‐dependent manner with a peak at 8 h and a return to baseline values at 20 h after stimulation. In vitro nuclear transcription assays determined that fucose augmented the rate of transcription of the TNF‐α gene, and inhibition of de novo transcription with actinomycin D indicated that the turnover rate of the TNF‐α mRNA was not affected by fucose stimulation. We also determined that fucose did not modulate the mRNA expression of the pore‐forming protein, a major lytic protein involved in lymphocyte cytotoxicity. Specific neutralizing antibodies indicated that TNF‐α was not an effector molecule in fucose‐activated killing of K562 or Raji target cells but that this cytokine had an essential role in the induction of the augmented killing by α‐l‐fucose.

ISSN:0741-5400    

DOI:10.1002/jlb.52.2.188

出版商:Wiley    

年代:1992

数据来源: WILEY

摘要:

AbstractIn this study, we examined the role of interleukin‐6 (IL‐6) in the development of chronic lung inflammatory conditions, using a mouse model of hypersensitivity pneumonitis established by intranasal instillation of the thermophilic actinomyceteFaeni rectivirgula.Challenged mice developed an early neutrophilic response at 24 h, followed by a macrophage/lymphocyte recruitment. The impact of IL‐6 on the development of the inflammatory response was assessed by giving infusions of a monoclonal antibody against IL‐6 so as to deplete endogenous levels of this cytokine or by giving exogenous IL‐6 to challenged mice. Mice challenged in‐tranasally with the actinomycete and given the anti–IL‐6 antibody developed a strong, sustained neutrophilic response, with a significantly higher lung free cell number than control mice. Assessment of fibrosis by measuring lung hydroxyproline levels showed that challenged mice given anti–IL‐6 developed more significant fibrosis than control mice. Conversely, infusions with IL‐6 diminishedF.rectivirgula–induccd cell recruitments and the fibrotic response in the lungs. Moreover, alveolar macrophages from mice given 2 weeks ofF. rectivirgulatreatment released high levels of tumor necrosis factor a (TNF‐α) bioactivity upon in vitro lipopolysaccharide challenge, compared to mice instilled with saline only. This TNF‐α activity produced by macrophages was decreased by in vivo IL‐6 treatment and enhanced by in vivo neutralization with anti‐IL‐6. These observations suggest that IL‐6 may play a role in regulating the cellular recruitment in the lungs during an inflammatory response, with dramatic consequences for the cellular profile in the bronchoalveolar lavage and the subsequent fibrosis.

ISSN:0741-5400    

DOI:10.1002/jlb.52.2.197

出版商:Wiley    

年代:1992

数据来源: WILEY