流体低切应力对内皮细胞IL—8mRNA表达的影响

为证实内皮细胞IL-8表达不仅受化学因子的调节,而且还受力学因素的影响。我们用低层流切应力（4.2dyne/cm^2）处理培养的人脐静脉内皮细胞后采用RT-PCR法检测内皮细胞IL-8基因表达,并用免疫细胞化学染色法检测内皮细胞内NF-kB激活的影响,结果发现：①未用切应力处理和切应力作用0.5h后内皮细胞IL-8mRNA表达量很少,切应力作用1h后内皮细胞IL-8 mRNA表达增加,2h进一步增加。②未用切应力处理和切应力作用0.5h内皮细胞核内NF-kBp65染色阴性,切应力作用1h呈弱阳性,2h呈阳性。提示低层流切应力可诱导内皮细胞表达增加,IL-8表达量与切应力作用时间有关。流体切应力可诱导内皮细胞内NF-kB的激活,激活程度与作用时间有关。低切应力诱导内皮细胞表达IL-8,可能在急性炎症和动脉粥样硬化发生、发展过程中具有重要作用。     

凝血酶对人重组内皮细胞衍生IL—8融合蛋白转换作用

本文报道利用基因工程技术在大肠杆菌中表达出入内皮细胞衍生IL-8(EDhIL-8)与细菌蛋白lacZ 的融合蛋白lac-hIL-8和lac-T-hIL-8,后者含有一个人工合成凝血酶切点。EDhIL-8上含有一个凝血酶切点,凝血酶可以将lac-hIL-8及以前表达的MS2-hIL-8水解为有生物活性的天然IL-8,而对含有两个凝血酶切点的lac-T-hIL-8无水解作用。这些结果提示凝血酶的功能不仅依赖于所识别的氨基酸,而且依赖于这些氨基酸形成的构象。     

IL—8受体的研究进展

ＩＬ－８是具有趋化功能的细胞因子，近年来发现它还有多种其它生物学功能，其生物学效应通过特异ＩＬ－８受体介导。已克隆，纯化的两种特异性ＩＬ－８Ｒ，都和ＩＬ－８有高亲和力，属于Ｇ蛋白偶联受体超家族。近来又克隆成功存在于红细胞膜上，能与多种趋化因子结合的ＩＬ－８受体，称趋化因子受体，并证实亦即血型Ｄ抗原。     

流体切应力作用强度对内皮细胞IL一8生成的影响

血管内皮细胞衬于血管腔的表面,是血流机械应力的主要感受者.切应力可以直接调节内皮细胞生物活性物质的合成和分泌,其中包括诱导内皮细胞生成IL一8,而且IL一8的生成量与切应力作用时间有关.为阐明内皮细胞IL一8的生成除了与切应力的作用时间有关外还与切应力的强度有关,我们用不同强度的流体切应力(2.09、4.61、6.1 9、8.51、10.50、12.59、14.41、17.22、18.32 dyne/cm2)处理培养的人脐静脉内皮细胞,然后采用双抗体夹心ABC-ELISA技术检测内皮细胞IL一8蛋白质的生成.结果显示未用切应力处理的内皮细胞只有极少量的IL一8蛋白质生成;切应力处理内皮细胞后,低切应力(2.09dyne/cm2)时IL一8蛋白质生成量明显增加,约为高切应力(18.32 dyne/cm2)时IL-8蛋白质生成量的6(作用5 h)或7倍(作用6 h).IL一8蛋白质生成量与内皮细胞所施加的切应力强度呈反变关系;直线回归方程5 h时为y=760.12-36.06x,相关系数γ=-0.978;6 h时为y=781.87-36.66x,相关系数γ=-0.980.式中y为切应力作用下内皮细胞IL-8的生成量;x为施加于内皮细胞的切应力强度(dyne/cm2).不同的切应力作用时间(5 h、6 h)均表现出相同的IL-8蛋白质生成量随切应力强度的变化规律.提示流体切应力诱导内皮细胞生成IL一8的量,不仅与切应力的作用时间有关,而且IL-8的生成量与切应力强度有关.流体低切应力诱导内皮细胞IL-8的生成量急剧增高,可能在急性炎症和动脉粥样硬化的发生、发展过程中具有重要作用.     

IL—3、GM—CSF扩增骨髓树突状细胞及促进MHC Class—I途径抗原提呈

目的：研究 IL-3、GM-CSF能否扩增小鼠骨髓树突状细胞，并通过 MHC Class-I途径提呈外源性抗原。方法：以C57BL/6小鼠骨髓2 h粘附细胞作为树突状细胞来源，在 IL-3（10 ng/ml）及 GM-CSF（1000 U/ml）条件下培养5 d，观察细胞形态、数量和免疫表型的变化，以及对外源性抗原的摄取能力和Class-I途径提呈能力。结果：培养后细胞绝对计数显著增加，MHC分子及共刺激分子表达显著增加，对颗粒性抗原beads-OVA具有高效摄取能力，Class-I途径提呈beads-OVA及SIIFEKL表位的能力显著增强。结论：IL-3、GM-CSF能有效扩增具有高效抗原摄取和提呈能力的树突状细胞，提示在树突状细胞和肿瘤免疫治疗研究中具有重要价值。     

TNF—a对内皮细胞白介素—8基因表达的影响

IL-8作为一种趋化细胞因子在炎症反应中具有重要作用,其在内皮细胞内的表达受多种细胞因子的调节。本文用TNF-a孵育培养的人脐静脉内皮细胞不同时间后,用RT-PCR法检测内皮细胞内IL-8mRNA的表达,并用免疫细胞化学染色法检测内皮细胞内NF-kB的激活。结果发现：（1）未用TNF-a孵育的内皮细胞IL-8表达量很少,TNF-a孵育1小时后IL-8表达明显增加,3h进一步增加;6h IL-8表达降低,9h进一步降低至基础水平;（2）未用TND-a孵育的内皮细胞核NF-kB p65免疫细胞化学染色呈阴性,NF-a孵育1,3h后NF-kB p55免疫细胞化学染色呈阳性,6h时后呈弱阳性,9h后呈阴性。提示：TNF-a可诱导内皮细胞表达IL-8并可激活内皮细胞内NF-kB,二者的时相过程基本一致。作者认为TNF-a诱导IL-8在内皮细胞内表达可能与转录因子NF-kB的激活有关。     

流体切应力作用时间对内皮细胞IL-8 基因表达的影响

内皮细胞对力学环境变化敏感，流体切应力可以直接调节内皮细胞基因的表达。为阐明内皮细胞白细胞介素-8（IL-8）基因的表达除受化学因子的调节外还受力学因素的影响，本文用流体切应力（2.23、4.20、6.08dyne/cm^2）处理培养的人脐静脉内皮细胞，然后采用定量RT-PCR的方法检测内皮细胞IL-8基因的表达情况。结果显示：未用切应力处理的内皮细胞没有IL-8基因的表达；切应力处理内皮细胞后，1h IL-8mRNA表达增加，2hIL-8mRNA表达量至最高值，3hIL-8mRNA表达量开始下降，4h后IL-8mRNA持续低表达；各实验组（2.23、4.20、6.08dyne/cm^2）均表现出相同的IL-8mRNA随时间的变化规律。提示流体切应力确可诱导内皮细胞表达IL-8，而且IL-8的表达量与切应力作用时间有关，呈双相性变化。流体切应力诱导内皮细胞表达IL-8，可能在急性炎症和动脉粥样硬化的发生、发展过程中具有重要作用。     

肝素通过TLR4减少脂多糖刺激的人内皮细胞IL-8表达

目的:观察肝素对脂多糖(lipopolysaccharide, LPS)刺激的人内皮细胞白细胞介素8(interleukin-8,IL-8)水平的影响,并探讨Toll样受体4(Toll-like receptor 4,TLR 4)在其中的可能影响。方法:用LPS(10 mg/L)刺激人肺微血管内皮细胞诱导损伤,肝素治疗组提前15 min分别加入100 U/L及10³ U/L普通肝素,正常对照组加入等量磷酸盐缓冲液。分别在刺激2、6、12 h收集细胞上清,采用酶联免疫吸附法测定上清中IL-8的浓度。在刺激2、6、12 h收集细胞提取RNA,应用实时荧光定量聚合酶链反应检测各组细胞中IL-8、CD14及TLR4 mRNA水平变化。结果:与正常对照组比较,LPS刺激组IL-8 mRNA水平增高,6 h达到高峰,其蛋白水平于12 h达到高峰。LPS刺激下TLR4 mRNA水平增高,6 h达到高峰,肝素降低其水平,差异有统计学意义(P＜0.05)。未检测到CD14 mRNA的表达。结论:LPS刺激下人肺微血管内皮细胞IL-8表达增加。肝素可能通过调节TLR4降低IL-8的水平,从而发挥保护作用。     

Split activity of interleukin-10 on antigen capture and antigen presentation by human dendritic cells: Definition of a maturative step

Human CD1⁺ CD14^- dendritic cells (DC) can be derived from CD14⁺ monocytes using granulocyte/monocyte colony-stimulating factor and interleukin (IL)-4. We have previously shown that IL-10 pre-treatment of such DC significantly inhibited their antigen-presenting capacity to CD4⁺ T cell clones. In this study, we further analyze how IL-10 influences antigen presentation. We first investigated whether IL-10 could alter the early stage of antigen presentation, the capture of antigen. This can be mediated by mannose receptor (MR)-mediated endocytosis and by fluid-phase uptake through macropinocytosis. IL-10-treated DC showed an enhancement of both mechanisms of antigen capture, as indicated by the increase of fluorescein isothiocyanate-dextran uptake through MR and lucifer yellow uptake. However, IL-10-treated DC, irradiated or glutaraldehyde-fixed, were less efficient than untreated DC in stimulating mixed leukocyte reaction as well as in inducing the activation of peptide-specific T cell clones, indicating that IL-10 achieves its effects mainly by modifying the cell surface phenotype of DC. HLA class I and II, as well as intercellular adhesion molecule (ICAM)-1, lymphocyte function-associated antigen-3, B7-1, B7-2 and ICAM-3 expression were either significantly increased or essentially unchanged, and the ability to bind the epitope recognized by the T cell clones was also unaffected regardless of IL-10 treatment. Our study also indicates that as-yet unidentified accessory molecules may play an essential role in T cell activation. Thus, the IL-10-treated DC possess an increased capacity to capture antigen, with a concomitant decreased stimulatory activity. Our study suggests that IL-10-treated DC have the characteristics of highly immature DC (high capture ability, low stimulatory potency) and may represent an early maturative step of human DC of monocytic origin.     

Interleukin-10 prevents the generation of dendritic cells from human peripheral blood mononuclear cells cultured with interleukin-4 and granulocyte/ macrophage-colony-stimulating factor

We evaluated the effects of interleukin (IL)-10 on the differentiation of dendritic cells (DC) obtained by culturing plastic-adherent peripheral blood mononuclear cells for 7 days in presence of granulocyte/macrophage-colony-stimulating factor (GM-CSF)+IL-4. The addition of IL-10 at the initiation of culture resulted in the generation of macrophage-like cells with expressing high levels of CD14 and decreased levels of CD1a and CD1c. Furthermore, cells generated in presence of IL-10 secreted lower levels of IL-12, but higher levels of IL-8 compared with DC generated in absence of IL-10, both spontaneously and after CD40 engagement. Finally, cells generated in presence of IL-10 were less efficient than DC in stimulating the production of IL-2, interferon-γ, and IL-4 by allogeneic T cells. We conclude that IL-10 prevents the generation of DC induced by GM-CSF+IL-4 and favors the development of macrophages with a lower T cell stimulatory potential, but secreting higher levels of IL-8 than DC.     

The interleukin-8 receptor B and CXC chemokines can mediate transendothelial migration of human skin homing T cells

We studied the involvement of chemokines that bind to G protein-coupled receptors in the migration of skin homing T cells across a bilayer vascular construct (BVC) consisting of a fibroblast matrix underneath an activated endothelial (EC) monolayer. Based on the expression of the cutaneous lymphocyte-associated antigen (CLA), a skin homing receptor, CD45R0⁺ T cells freshly isolated from blood or HUT-78 cutaneous T lymphoma cells were separated into CLA⁺ and CLA⁻ subpopulations. These T cells were incubated on interleukin (IL)-1β and tumor necrosis factor-α-activated EC, and the number of transmigrated cells was determined. The chemokine IL-8 was selectively involved in the enhanced migration of CLA⁺ T cells across activated EC as demonstrated by blocking antibody to IL-8 but not to GRO-α, MCP-1 and RANTES. Identical results were obtained with both human umbilical vein EC (HUVEC) and microvascular skin EC (HDMEC). Pertussis toxin selectively inhibited the enhanced transendothelial migration (TEM) of CLA⁺ T cells, suggesting that CLA-dependent TEM depends on G_i protein-transmitted signals. Moreover, the IL-8 receptor B (IL-8RB) appeared to be functionally involved in TEM, as demonstrated by receptor desensitization with the CXC chemokines IL-8 and GRO-α and by blocking the IL-8RB with specific monoclonal antibodies. Although only the IL-8RB was involved in CLA-dependent TEM, mRNA encoding IL-8RA and IL-8RB was expressed by both CLA⁺ and CLA⁻ T cells. This correlated with IL-8RA and IL-8RB surface expression on these cells. Thus, the IL-8RB is selectively functional in TEM of T cells expressing the skin homing receptor CLA. Our results demonstrate a critical role for IL-8 and possibly other IL-8RB ligands in addition to the IL-8RB in TEM and suggest the involvement of these molecules in the homing of specific T cells to inflamed skin.     

IL-8对血管内皮细胞通透性的影响

目的研究白细胞介素-8（IL-8）对血管内皮细胞通透性的影响。方法采用Transwell弥散模型,以标志物漏出法检测IL-8不同浓度、不同作用时间对EA.hy926细胞单层通透性的影响;结晶紫染色法检测细胞形态学改变;透射电镜进行细胞连接形态学观察。结果IL-8可明显增加血管内皮细胞单层的通透性（P〈0．05）,呈一定的剂量和时间依赖关系;荧光倒置相差显微镜观察,随着IL-8浓度和作用时间的增加,细胞明显回缩,细胞间隙明显增加;透射电镜实验表明,随着IL-8浓度和作用时间的增加。细胞连接逐渐打开、破坏。结论IL-8以时间和剂量依赖方式引起血管内皮细胞通透性升高、细胞及细胞连接形态学的改变。     

The nature of the signals regulating CD8 T cell proliferative responses to CD8α+ or CD8α− dendritic cells

The CD8α^?-expressing dendritic cells (DC) of mouse spleen have been shown to be poor inducers of interleukin (IL)-2 production by CD8 T cells when compared to the CD8^? DC. As a consequence, CD8 T cells give a more prolonged proliferative response to CD8^? DC than to CD8⁺ DC. The possible mechanisms underlying these functional differences in DC subtype have been investigated. Inadequate co-stimulation did not underlie the poor T cell response to allogeneic CD8⁺ DC. Equivalent levels of B7-1 (CD80) and B7-2 (CD86) were found on the two DC subtypes and co-stimulator assays did not reveal any functional differences between them. Although CD8⁺ DC were found to die more rapidly in culture than CD8^? DC, this did not explain their reduced stimulatory ability. Neither prolonging DC survival in culture nor renewing the stimulator cells by repeated addition of freshly isolated DC had any significant effect on the T cell responses. Furthermore, later addition to the cultures of DC of the opposite type to the initiating DC did not reverse or eliminate the differential response to the initiating DC. The role of DC-derived soluble factors was examined by addition to the cultures of supernatants derived from freshly isolated or stimulated DC of the opposite type. This neither enhanced the poor stimulatory capacity of CD8⁺ DC nor inhibited the stimulation by CD8^? DC. Furthermore, addition of a series of cytokines that might have been produced by the DC did not eliminate the differences in T cell proliferation. Only the addition to the cultures of the growth factors IL-2 and IL-4 overcame the stimulatory difference between the two DC populations, confirming that the difference in T cell proliferative responses was a consequence of differences in induced cytokine production. The difference in the response of CD8 T cells to CD8⁺ and CD8^? DC is therefore determined by direct DC-T cell contact during the earliest stages of the culture and involves an undetermined and possibly new signaling system.     

IL-8对血管内皮细胞紧密连接的影响

目的 研究白细胞介素-8(IL-8)对血管内皮细胞紧密连接的影响.方法 采用免疫荧光染色检测经不同浓度和时间IL-8处理后EA.hy926细胞的3种紧密连接蛋白occludin、claudin-5和ZO-1的形态和分布;逆转录PCR(RT-PCR)检测3种蛋白mRNA的表达水平.结果 IL-8可改变内皮细胞紧密连接蛋白...     

白细胞介素-18干预诱导的树突状细胞表型和活性研究

目的：研究白细胞介素-18（IL-18）干预诱导的树突状细胞（DC）的表型和活性。方法:自人外周血单核细胞诱导DC，第5 d起分为IL-18组、TNF-α组和IL-18+TNF-α组，分别加IL-18、TNF-α及IL-18+TNF-α促成熟，用ELISA法测定上清中IL-12含量；用流式细胞仪测定培养8 d DC的CD1a、HLA-DR、CD83及CD86的表达；用MTT法检测3组DC诱导T细胞增殖的作用。用ELISA法测定3组DC刺激T细胞分泌干扰素γ(IFN-γ)的量。结果:IL-18组与TNF-α组CD1a、HLA-DR、CD83及CD86表达无差异，IL-18+TNF-α组CD1a、CD83及HLA-DR阳性率高于IL-18组。IL-18+TNF-α组IL-12量高于IL-18组和TNF-α组(P＜0.05)。IL-18组与TNF-α组DC刺激T细胞增殖作用无差异，IL-18+TNF-α组DC的作用强于IL-18组和TNF-α组。IL-18组和TNF-α组IFN-γ量无显著差异，IL-18+TNF-α组IFN-γ的量高于IL-18组和TNF-α组(P＜0.05)。结论:IL-18干预诱导的DC高表达表面分子，具有明显的免疫刺激活性，IL-18与 TNF-α合用作用更强。     

Divergent effects of interleukin-10 on cytokine production by mononuclear phagocytes and endothelial cells

Interleukin-10 (IL-10), a product of T helper type 2 (TH2) cells and monocytes, inhibits cytokine production in mononuclear phagocytes. Given the similarities and interrelationship between cells of the monocyte-macrophage lineage and endothelial cells, we examined the effects of IL-10 on vascular endothelium. Murine IL-10 induced low levels of IL-6 production and amplified induction of IL-6 by lipopolysaccharide (LPS) or IL-1 in the murine tEND.1 endothelioma line, used for these studies because it retains properties of normal endothelium. The effect was more evident after prolonged (48–72 h) exposure to IL-10. IL-10 had similar activity on other endothelioma lines, whereas it inhibited IL-6 production by peritoneal macrophages. Induction and amplification of cytokine production by IL-10 was associated with higher levels of mRNA, which were maintained longer (up to 48 h) than in controls. In addition to IL-6, murine IL-10 induced or amplified expression of the chemoattractant cytokines monocyte chemotactic protein-1 (MCP-1) and KG Human IL-10 inhibited IL-6 release by LPS-stimulated human peripheral blood mononuclear cells, whereas it did not interfere with cytokine production by LPS- or IL-1-stimulated human umbilical vein endothelial cells. The selective inhibitory action of IL-10 on mononuclear phagocytes versus endothelial cells may play a role in the pathophysiology of TH2-directed responses.     

鼻咽癌细胞中表达的人白细胞介素18(hIL-18)对鼻咽癌患者外周血 CD8+T细胞细胞毒活性增强作用的研究

目的探讨人白细胞介素18在鼻咽癌细胞中的表达能否提高鼻咽癌病人外周血CD8+T细胞的杀伤活性以及作用途径.方法构建人白细胞介素18的真核表达载体[pcDNA3.1(-)/hIL-18,转染人鼻咽癌细胞株SUNE;以转染的SUNE细胞和未转染的SUNE细胞为靶细胞,以鼻咽癌患者外周血的CD8+T细胞为效应细胞,混合培养12 h,用LDH释放法测定CD8+T细胞的细胞毒活性;用免疫组化法测定混合培养物中CD8+T细胞上Perlorin、Fas-L、Granzyme B的表达.结果所构建的真核表达载体在鼻咽癌细胞中能高效表达hIL-18;ELISA法测得转染阳性细胞培养上清液中hIL-18的含量为(85±10)pg/ml,而未转染的SUNE细胞的培养上清液中hIL-18的含量低于5 pg/ml.将表达hIL-18的SUNE细胞与鼻咽癌患者外周血CD8+T细胞混合培养12 h后,CD8+T细胞的细胞毒活性显著增强(P＜0.001),尤其是当效应细胞/靶细胞为101时,CD8+T细胞对转染的SUNE细胞的裂解率高达46.7%,而CD8+T细胞对未转染的SUNE细胞的裂解率仅为4.6%.免疫组化法表明,这种杀伤活性的增强与CD8+T细胞表达Perforin有关,而与Fas-L和Granzyme B途径无关.结论hIL-18能显著增强鼻咽癌患者外周血CD8+T细胞的体外杀伤活性,这种杀伤活性与CD8+T细胞表达Perlorin有关.