LPS直接诱导对肺微血管内皮细胞IL—8的表达及对PMN趋化作用影响的研究

目的探讨LPS的直接诱导作用对肺微血管内皮细胞(PMVEC)IL -8表达的影响及诱导发生的PMVEC对多形核中性粒细胞(PMN)趋化作用的影响。方法100ng/mlLPS刺激PMVEC0、0.5、1、2、4、6、8h或1ng/ml、10ng/ml、100ng/mlLPS刺激6h ,ELISA和原位杂交试验分别检测培养基上清液中分泌的IL -8及PMVEC内IL -8mRNA的表达 ,同时琼脂糖平板法检测对PMN的趋化作用 ,并通过抗IL -8的抗体抑制试验观察对趋化作用的影响。结果LPS能显著促进PMVEC表达IL -8 ,包括促进IL -8mRNA的表达及IL -8的分泌。在时间上mRNA的表达先于IL -8分泌。LPS能促进PMVEC对PMN的趋化 ,随刺激作用的持续 ,诱导的PMVEC对PMN的趋化作用加强。抗IL -8抗体能显著抑制对PMN的趋化作用(P<0.01)。结论表明细菌致病因子LPS的直接诱导能促进PMVEC高效表达和分泌IL -8 ,从而为PMN的迁移提供必需的物质条件 ,发挥对PMN的趋化作用而参与导致肺损伤     

脂多糖对肺微血管内皮细胞IL-8表达的影响及其调控机理

目的探讨脂多糖(LPS)的直接诱导作用对肺微血管内皮细胞(PMVEC)IL-8表达的影响及通过核因子κB(NF-κB)的调控机理。方法肺微血管内皮(PMVEC)细胞生长至80 %以上融合度时用于实验。加入LPS以100ng/ml浓度刺激细胞分别至0、0.5、1、2、4、6、8h ,或LPS分别以1ng/ml、10ng/ml、100ng/ml刺激细胞至1h或6h为检测时相点 ,每组6个标本。至预定时相点离心收集培养液上清 ,行IL -8ELISA检。用原位杂交试验检测培养液上清中分泌的IL -8及PMVEC内IL-8mRNA的表达 ;凝胶电泳迁移率分析 (EMSA)检测NF-κB的活化 ,以积分灰度值表示NF-κB的活性变化。观察NF -κB活化抑制 (PDTC)对IL-8表达的影响。结果LPS能显著促进PMVEC表达IL -8,随刺激时间延长IL -8水平逐渐升高 ,与0h相组比 ,100ng/mlLPS刺激后从2小时开始即有明显上升 (P<0.05) ,8h达到峰值 ,为5.86±0.68ng/ml(P<0.01)。与对照组比 ,1ng/mlLPS刺激6h即能显著诱导IL-8的表达(P<0.05) ,10ng/ml、100ng/ml的诱导作用非常显著(P<0.01) ,随着LPS浓度的增加而增加。LPS刺激后能明显地诱导IL -8mRNA的表达。100ng/mlLPS刺激后从1h开始即在胞浆中显示IL-8mRNA的强阳性表达 ,随作用时间延长 ,IL-8mRNA表达增加。至6h达到高峰 ,8hIL -8mRNA表达略有下降。同时显示IL -8mRN     

LPS诱导肺微血管内皮细胞与PMN的粘附作用及核调控机理的实验研究

目的研究LPS诱导的肺微血管内皮细胞(PMVEC)与(PMN)的粘附作用及调控机制。方法100ng/mlLPS刺激PMVEC0、2、4、6、8h或10ng/ml、50ng/ml、100ng/mlLPS刺激6h ,检测PMVEC -PMN粘附率、PMVECICAM -1的表达(免疫细胞化学)。EMSA方法检测NF -κB的活化。并通过加入An ti_ICAM -1抗体或活化阻断剂观察对PMVEC -PMN粘附率的影响。结果PMVECICAM -1的表达及与PMN的粘附与LPS的刺激呈时相 -剂量依赖方式。LPS的刺激迅速活化NF -κB ,60min达到高峰 ,后逐渐下降。Anti-ICAM -1抗体、PDTC能显著降低PMVEC -PMN粘附(P<0.001)。结论LPS刺激诱导NF -κB的活化 ,启动ICAM -1的合成表达 ,从而导致PMVEC -PMN的粘附增加     

LPS的直接诱导对肺微血管内皮细胞ICAM-1的表达及对PMN黏附作用影响的研究

目的探讨内素毒(Endotoxin LPS)的直接诱导作用对肺微血管内皮细胞(PMVEC)ICAM-1表达的影响及诱导发生的PMVEC对多形核中性粒细胞(PMN)黏附作用的影响。方法100ng/m l LPS刺激PMVEC 0、2、4、6、8 h或10、50、100 ng/m l LPS刺激6 h,同时检测PMVEC ICAM-1的表达(免疫细胞化学法)、PMVEC-PMN黏附率及抗ICAM-1抗体对黏附作用的影响,并进行PMVEC与PMN黏附作用的扫描电镜观察。结果LPS的直接刺激可诱导PMVEC ICAM-1的表达增加,且表现为随LPS刺激的时间、剂量增加而增加;同时LPS直接刺激也促进了PMVEC对PMN的黏附率增加,其变化在时间与方式上几乎与ICAM-1的表达增加同步。Anti-ICAM-1抗体可以显著地抑制LPS诱导的PMVEC-PMN黏附(P<0.01)。扫描电镜可以直观地显示PMVEC-PMN黏附的超微结构表现,并且首次通过这种方式观察到了“间接系链”现象的存在。结论表明细菌致病因子LPS的直接诱导可以促进PMVEC表达ICAM-1,从而为PMVEC-PMN的黏附提供物质基础,而“间接系链”的发生更扩大和巩固了黏附效果。     

固有免疫在脂多糖、烟曲霉菌诱导的角膜细胞耐受中的作用

研究烟曲霉菌(AF)、脂多糖(LPS)能否引起角膜细胞的耐受反应,增强角膜对病原体刺激的防御功能。小剂量AF、LPS分别预处理永生化人角膜上皮细胞(THCE)和永生化人角膜基质细胞(THSF),20 h后给予大剂量AF或LPS再次刺激。于再次刺激后4 h收集细胞上清,酶联免疫吸附试验(ELISA)检测细胞因子IL-8的分泌,趋化实验检测LPS预处理引起THSF对PMN趋化的改变。于再次刺激后1 h收集细胞,实时RT-PCR检测细胞因子IL-8 mRNA和抗菌肽CCL20和LL-37 mRNA的表达。结果显示AF、LPS分别预处理THCE和THSF均可显著抑制IL-8的分泌。LPS预处理THSF抑制IL-8 mRNA的表达,增加CCL20和LL-37 mRNA的表达,并且抑制中性粒细胞(PMN)向角膜细胞的趋化。因此角膜细胞的耐受反应可避免过度的炎症反应,减轻角膜感染,在角膜炎症中起保护性作用。     

MyD88/PI3-K/NF-κB途径介导脂氧素A4拮抗LPS诱导大鼠内皮细胞的白细胞介素合成

目的研究脂氧素A4（LXA4）对脂多糖（LPS）诱导血管内皮细胞合成白细胞介素（IL）-1β、IL-6、IL-8的影响，并探讨其机制。方法对体外培养大鼠肺微血管内皮细胞（PMVEC），用LXA4孵育，再加入LPS；或单用LPS刺激PMVEC。在孵育后用酶联免疫吸附法（ELISA）检测培养上清中的IL-1β、IL-6、IL-8蛋白表达；用RT-PCR法检测IL-1β、IL-6、IL-8的mRNA表达。应用Western blot法检测磷酸化的磷脂酰肌醇-3-激酶（PI3-K）、髓细胞分化因子88（MyD88）的表达。应用凝胶电泳迁移率试验（EMSA）测定核因子-κB（NF-κB）和活化蛋白-1（AP-1）的DNA结合活性。结果LXA4呈剂量依赖性地抑制LPS诱导的PMVEC的IL-1β、IL-6、IL-8的蛋白合成与mRNA表达，抑制PI-3K的表达，抑制NF-κB和AP-1的DNA结合活性，但不影响LPS诱导的MyD88表达。结论LXA4通过下调PI3-K的表达和NF-κB、AP-1的DNA结合活性，拮抗LPS对PMVEC的IL-1β、IL-6、IL-8合成的诱导作用。     

LPS诱导肺微血管内皮细胞ICAM-1的表达及NF-κB作用的实验研究

目的研究LPS诱导的肺微血管内皮细胞 (PWVEC)ICAM -1的表达及调控机制。方法100ng/mlLPS刺激PMVEC0h、2h、4h、6h、8h或10ng/ml、50ng/ml、100ng/mlLPS刺激6h ,免疫细胞化学检测PMVECICAM -1的表达。凝胶电泳迁移率变化分析检测NF -κB的活化。并通过加入活化阻断剂PDTC观察对PMVECICAM -1表达的影响。结果PMVECICAM -1的表达与LPS的刺激呈时相 -剂量依赖方式。LPS的刺激迅速活化NF -κB ,60min达到高峰 ,后逐渐下降。PDTC能显著降低ICAM -1的表达 (P<0 .01)。结论LPS刺激诱导NF-κB的活化 ,启动ICAM -1的合成表达。     

LPS诱导肺微血管内皮细胞ICAM-1的表达及 NF-κ B作用的实验研究

目的研究 LPS诱导的肺微血管内皮细胞( PWVEC) ICAM- 1的表达及调控机制.方法 100ng/ml LPS刺激 PMVEC 0h、2h、4h、6h、8h或 10ng/ml、50ng/ml、100ng/ml LPS刺激 6h,免疫细胞化学检测 PMVEC ICAM- 1的表达.凝胶电泳迁移率变化分析检测 NF- κ B的活化.并通过加入活化阻断剂 PDTC观察对 PMVEC ICAM- 1表达的影响.结果 PMVEC ICAM- 1的表达与 LPS的刺激呈时相 - 剂量依赖方式.LPS的刺激迅速活化 NF- κ B,60min达到高峰,后逐渐下降.PDTC能显著降低 ICAM- 1的表达( P<0. 01).结论 LPS刺激诱导 NF- κ B的活化,启动 ICAM- 1的合成表达.     

白细胞介素-13对肾小球系膜细胞炎症反应的拮抗作用

目的:探讨白细胞介素-13(IL-13)对肾小球系膜细胞(MC)炎症反应的调节作用。方法:ELISA法测定体外培养MC上清中TNF-α浓度。流式细胞术检测MC膜表面ICAM-1表达。逆转录聚合酶链式反应(RT-PCR)评估MCTNF-αmRNA及ICAM-1mRNA表达。结果:未受刺激的MC无TNF-αmRNA及其蛋白表达。经脂多糖(LPS)(10mg/L)刺激后,MC可高表达TNF-αmRNA及其蛋白。IL-13浓度为1μg/L、10μg/L时显著抑制LPS诱导MC表达TNF-αmRNA及其蛋白。IL-13(0.1μg/L)无抑制作用,IL-13(100μg/L)时完全抑制LPS诱导MC分泌TNF-α。无任何刺激时,MC低表达ICAM-1。TNF-α(100μg/L)诱导MC高表达ICAM-1mRNA及其蛋白。IL-13(10μg/L)和TNF-α(100μg/L)共作用MC,各时点均显示IL-13对TNF-α诱导MC表达ICAM-1mRNA及蛋白有抑制作用。结论:IL-13既抑制LPS刺激MC分泌TNF-α,也抑制TNF-α诱导MC表达膜糖蛋白ICAM-1。提示IL-13能从多个环节抑制MC的炎症反应。     

槲皮素对LPS诱导的中性粒细胞产生白介素6的影响

目的 研究离体培养的人中性粒细胞在被LPS激活的情况下,槲皮素对中性粒细胞产生IL-6的影响。方法 运用ELISA法检测槲皮素对LPS诱导的中性粒细胞分泌IL-6的影响;运用流式细胞术检测槲皮素对LPS活化的中性粒细胞内IL-6的蛋白水平的影响;运用逆转录PCR（RT-PCR）技术检测槲皮素对LPS活化的中性粒细胞表达IL-6 mRNA的影响。结果 在无刺激的情况下中性粒细胞不产生IL-6,LPS（1μg／mL）以时间依赖性的方式诱导中性粒细胞表达IL-6 mRNA,合成并分泌IL-6,并在16h达到高峰。然而,预先用槲皮素（40μmol／L）处理中性粒细胞30min后,LPS诱导的中性粒细胞表达IL-6 mRNA,合成并分泌IL-6则受到了抑制。结论IL-6是炎症早期重要的促炎症因子。因此,槲皮素抑制LPS诱导中性粒细胞产生IL-6,提示槲皮素可能通过对炎症因子负性调控而发挥其抗炎作用。     

Signal pathway involved in inhibition by lipoxin A4 of production of interleukins induced in endothelial cells by lipopolysaccharide

Objective and design:  We examine whether lipoxin A₄4 (LXA₄) inhibits production of interleukins (ILs) in endothelial cells and what signal pathway might participate in the actions of LXA₄. Methods:  Cultured pulmonary microvascular endothelial cells (PMVEC) were treated with lipopolysaccharide (LPS), with or without preincubation with LXA₄. Results:  The results showed that LPS induced production of IL-1β, IL-6 and IL-8 in rat PMVEC, upregulated the expressions of myeloid differentiation factor 88 (MyD88), phosphorylated p38 and p42/44 mitogen-activated protein kinase (MAPK), phosphorylated phosphoinositide 3-kinase (PI3-K), DNA-binding activities of nuclear factor-κ B (NF-κB) and activator protein-1(AP-1). The blockade of p38 MAPK, p42/44 MAPK, PI3-K, NF-κB or AP-1 partially inhibited production of IL-1β, IL-6 and IL-8 stimulated by LPS, respectively. LXA₄ significantly inhibited LPS-stimulated secretion of protein and expressions of mRNA of IL-1β, IL-6 and IL-8, activation of p38 MAPK, p42/44 MAPK, PI3-K, NF-κB and AP-1 but not MyD88 in PMVEC. Conclusions:  LXA₄ inhibits synthesis of IL-1β, IL-6 and IL-8 in PMVEC and this antagonism is related to PI3-K, p38 and p42/44 MAPK, NF-κB and AP-1 pathway-dependent signal transduction. Received 7 August 2007; returned for revision 21 December 2007; received from final revision 17 February 2008; accepted by M. Katori 11 March 2008     

Autoregulatory effect of interleukin-10 on proinflammatory cytokine production by Porphyromonas gingivalis lipopolysaccharide-tolerant human monocytes

Pretreatment of human peripheral blood monocytes with a very low concentration (0.1 ng/ml) of Porphyromonas gingivalis lipopolysaccharides (LPS) resulted in a significant decrease of interleukin-6 (IL-6) production, but not IL-8 production, by restimulation of a high concentration (1 microg/ml) of the same LPS. In contrast, the same pretreatment with Escherichia coli LPS resulted in the enhanced production of both IL-6 and IL-8 after restimulation. The selective induction by P. gingivalis LPS tolerance of IL-6 production developed in a time-dependent manner during the primary culture. P. gingivalis LPS-pretreated cells were also refractory to a high-dose E. coli LPS restimulation in terms of IL-6 production. The expression of IL-6 mRNA decreased 10 h after restimulation of P. gingivalis LPS-pretreated monocytes. Furthermore, an up-regulation of anti-inflammatory cytokine IL-10 upon a second high-dose LPS rechallenge occurred at the same time point in the pretreated cells. We studied the role of IL-10 in the process of IL-6 down-regulation. Neutralization by an anti-IL-10 polyclonal antibody prevented IL-6 down-regulation in P. gingivalis LPS-pretreated monocytes, whereas IL-8 production was not affected. Addition of exogenous IL-10 during the high-dose LPS stimulation of untreated cells substituted for the LPS pretreatment and resulted in the inhibition of IL-6 production in a dose-dependent manner. A higher dose of IL-10 was required to suppress IL-8 synthesis from monocytes. Our data suggest that IL-10 mediates IL-6 down-regulation in P. gingivalis LPS-tolerant monocytes in an autocrine manner.     

Production of interleukin-1-alpha and -beta by human peripheral polymorphonuclear neutrophils

The mechanism of the production of interleukin-1 (IL-1) by human peripheral polymorphonuclear neutrophils (PMN) was investigated. Supernatants of PMN stimulated with 30 micrograms/ml lipopolysaccharide (LPS) were used as extracellular IL-1 and supernatants of their lysate as intracellular IL-1 source. IL-1 activity was measured by the C3H/HeJ thymocyte co-mitogenic assay. The supernatants from PMN stimulated with LPS for 72 h showed IL-1 activity which had an apparent molecular weight of 15-20 kilodaltons and pI of 5.0 and more than 8.5. It was neutralized with anti-IL-1 antibodies and it lacked IL-2 activity. Our time course study of the IL-1 assay with neutralization by anti-IL-1-alpha and -beta antibodies indicated that the extracellular IL-1-beta activity appeared predominantly in the early incubation periods, whereas alpha activity appeared predominantly in the late periods. Intracellular IL-1-alpha but not beta activity was detected mainly at the intermediate incubation periods. These data indicate that PMN stimulated with LPS produce both IL-1-alpha and -beta, and release IL-1-beta first and IL-1-alpha later.     

Human alveolar macrophage gene expression of interleukin-8 by tumor necrosis factor-alpha, lipopolysaccharide, and interleukin-1 beta

The alveolar macrophage (AMO) in its pivotal position for pulmonary host defense may play a prominent role in the orchestration of polymorphonuclear leukocyte (PMN) diapedesis. We demonstrate that the human AMO may participate in these inflammatory events through the production of a novel neutrophil chemotactic factor, interleukin-8 (IL-8). The induction of AMO-derived IL-8 by tumor necrosis factor (TNF), lipopolysaccharide (LPS), and interleukin-1 (IL-1 beta) was shown to be both dose and time dependent. Maximal IL-8 gene expression, as assessed by Northern blot analyses, was achieved with 20 ng/ml and 1 microgram/ml, respectively, for each of the cytokines and LPS. A kinetic study of TNF-, IL-1 beta-, and LPS-treated AMOs showed significant steady-state IL-8 mRNA accumulation post-stimulation at 1 h, peaking by 8 h, with a decline over the next 16 h. Immunohistochemical staining using rabbit anti-human IL-8 antibody demonstrated significant immunolocalization of cell-associated IL-8 antigen at 4 h, with persistence over the next 20 h. Chemotactic bioactivity peaked by 8 h, with continued production over the next 16 h. Chemotactic bioactivity from AMO-conditioned media was inhibited by IL-8 antiserum by 2, 31, 44, and 47%, respectively, for unstimulated control, LPS-, IL-1 beta-, and TNF-treated cells. Preimmune serum had no effect on chemotactic activity. These data support the central role of the AMO in the elicitation of PMNs into the lung via the production of IL-8.     

LPS刺激诱导人卵巢癌细胞株Toll样受体4表达及细胞免疫调节

目的 探讨脂多糖(LPS)刺激对体外培养的人卵巢癌细胞株SKOV3的生长、Toll样受体4(TLR4)的表达、细胞活性氧(ROS)表达及6种炎性细胞因子分泌水平变化的影响.方法 用流式细胞仪测定不同浓度LPS刺激SKOV3 4 h后TLR4的表达水平;用LPS分别刺激SKOV3细胞不同时间后,MTT法检测细胞增殖情况,流式细胞仪分析TLR4表达、细胞周期分布、ROS表达水平以及细胞因子分泌水平.结果 TLR4表达与LPS作用浓度之间存在浓度依赖性和最大量效曲线关系;LPS刺激组与正常组的细胞增殖、细胞周期PrI值(细胞增殖指数,S+G_2/M)、ROS表达水平、细胞因子分泌水平均有显著性差异.结论 LPS具有诱导卵巢癌细胞TLR4表达、活性氧表达、炎症因子分泌以及细胞增殖和抑制的作用.     

Bacterial lipopolysaccharide suppresses the expression of lipoprotein lipase in murine macrophages: a process independent of tumor necrosis factor or interleukin 1

Lipopolysaccharide (LPS) modulates macrophage functions and induces the synthesis and secretion of tumor necrosis factor (TNF) and interleukin 1 (IL-1) in these cells. The latter two factors but not LPS suppress lipoprotein lipase (LPL) synthesis and secretion in adipocytes. Since the regulation of LPL secretion in macrophages is rather poorly understood, we investigated the effect of the macrophage activator LPS on LPL secretion by macrophages. LPS suppressed in a dose- and time-dependent manner the heparin-induced secretion of LPL from the macrophage-like tumor cell line J774.1 and from bone marrow derived mononuclear phagocytes (BMM). Suppression of LPL secretion from J774.1 and that from BMM reached about 66 and 50%, respectively, within 8 h of exposure to 500 ng/ml LPS. LPS did not inhibit the enzymic activity of LPL when added directly to the cell free enzyme assay system. Human recombinant TNF (1000 U/ml) and murine recombinant IL-1 (100 U/ml) did not affect LPL secretion or cell proliferation in the J774.1 cell line over a period of 72 and 24 h, respectively. Thus LPS regulates macrophage secretion of LPL in a mechanism independent of the induction of autocrine production of TNF and IL-1, and possesses a disparate pattern of regulation to that expressed by adipose tissue cells.     

Expression of interleukin-8 by lipopolysaccharide-stimulated bone marrow-derived mononuclear cells.

Interleukin-8 (IL-8) is a potent neutrophil chemoattractant, produced by a variety of immune and nonimmune cells in response to exogenous and host-derived inflammatory stimuli. We demonstrate here that a suspension of normal bone marrow mononuclear cells, consisting principally of myeloid precursors, produces IL-8 in response to stimulation with lipopolysaccharide (LPS). IL-8-specific mRNA is rapidly induced, being detected first 30 min after stimulation. IL-8 is detected by enzyme-linked immunosorbent assay within 2 h of stimulation, with steady a increase in its level through 72 h. Further studies demonstrated that LPS could serve as a primary stimulus for the expression of IL-8, since LPS challenge in the presence of cycloheximide resulted in superinduction of bone marrow mononuclear cell-derived IL-8 mRNA. These investigations suggest that the stimulatory effect of LPS is independent of other cytokines such as IL-1 beta. When compared with LPS, IL-1 beta proved to be a weak signal for the expression of IL-8 by bone marrow mononuclear cells. In a dose-response study, the maximum stimulatory concentration of IL-1 beta (300 pg/ml) resulted in the production of 500 pg of IL-8 per 10(6) cells, whereas 1 microgram of LPS resulted in the production of 5.5 ng/10(6) cells. Although IL-1 beta was not a particularly potent stimulus for IL-8 production by bone marrow mononuclear cells, peripheral blood mononuclear cells were highly susceptible to IL-1 beta challenge. In addition, the potential dependence of LPS-induced marrow-derived IL-8 production on the intermediate synthesis of IL-1 beta was further investigated. Results of studies assessing kinetics, addition of cycloheximide, and blocking with IL-1 beta neutralizing antibody were all consistent with the ability of LPS to directly induce bone marrow-derived IL-8 independently of IL-1 beta. These investigations demonstrate that bone marrow may be a significant source of IL-8 and may play a significant role in acute infectious, inflammatory responses.     

Adrenaline suppression of the macrophage nitric oxide response to lipopolysaccharide is associated with differential regulation of tumour necrosis factor-alpha and interleukin-10

Adrenaline is a catecholamine hormone secreted by the adrenal medulla in response to acute stress. Previous studies have shown that adrenaline suppresses the nitric oxide (NO) response of murine macrophages (M phi s) stimulated in vitro with lipopolysaccharide (LPS). We have now extended these studies to examine the effects of adrenaline on the production of tumour necrosis factor alpha (TNF-alpha) and interleukin-10 (IL-10). Our results showed that NO, TNF-alpha and IL-10 were concurrently produced following in vitro LPS (10 micrograms/ml) stimulation of murine peritoneal M phi s. Adrenaline suppressed both NO and TNF-alpha with concomitant up-regulation of the IL-10 response above that seen with LPS alone. In this in vitro model of LPS stimulation we demonstrated that TNF-alpha was required for NO production, as the TNF-alpha neutralizing monoclonal antibody, TN3.19.12, abolished the response; in contrast, IL-10 suppressed NO. In order to determine any functional consequence of adrenaline-mediated IL-10 augmentation on NO production, M phi s were stimulated with LPS and specific neutralizing anti-IL-10 antibodies were added to the cultures. The LPS NO response was suppressed to 43% of the control value by adrenaline (10(-8) M) and an irrelevant control antibody had no effect on the adrenaline-mediated inhibition of NO, but anti-IL-10 treatment restored the NO response to levels similar to those observed with LPS alone. Furthermore, we demonstrated that exogenous TNF-alpha, at a dose range of 1.9-50 ng per ml, also restored the nitrite response to LPS in the presence of adrenaline. Together, the observations that neutralization of IL-10 and addition of TNF-alpha abrogate adrenaline's inhibition of NO, suggest that this hormone suppresses NO partly through up-regulation of IL-10 which, in turn, may suppress TNF-alpha that is required for NO production. Finally, we also observed that the M phi-activating cytokine, interferon-gamma (IFN-gamma), attenuated the inhibitory effect of adrenaline on the LPS NO response.