C-反应蛋白诱导人肾小管上皮细胞凋亡

目的:探讨与微炎症状态相应的C-反应蛋白(CRP)水平是否诱导肾小管上皮细胞凋亡。方法:以微炎症状态相应的CRP浓度刺激HK-2细胞。采用AnnexinⅤ-FITC、PI染色和流式细胞术检测凋亡细胞的百分率。采用Hoechst 33258染色观察肾小管上皮细胞凋亡的形态学改变。比色法检测细胞caspase-3活性。Real-time PCR检测促凋亡基因bax、抗凋亡基因bcl-2的mRNA表达。结果:CRP呈剂量和时间依赖性地诱导HK-2细胞凋亡,细胞凋亡在CRP浓度为10 mg/L时达高峰,在20 mg/L时则以晚期凋亡和坏死为主。Hoechst 33258细胞核染色显示CRP作用的HK-2细胞呈现染色质浓缩、碎裂或染色质边集等细胞凋亡的特点。CRP增高细胞caspase-3的酶活性、上调促凋亡基因bax的表达和下调抗凋亡基因bcl-2的表达。结论:CRP轻度增高可诱导肾小管上皮细胞凋亡。     

姜黄素对MRL/lpr狼疮鼠肾组织富含脯氨酸的酪氨酸激酶2信号转导途径表达的影响

目的 探讨富含脯氨酸的酪氨酸激酶2(PYK2)信号转导途径在MRL/lpr模型鼠狼疮肾炎中所起的作用以及姜黄素对PYK2信号转导途径活化的影响.方法 选用MRL/lpr转基因狼疮鼠为研究对象,给予姜黄素干预治疗后,采用免疫组化方法研究狼疮鼠肾脏磷酸化PYK2的组织分布情况,采用Western blot方法研究磷酸化PYK2蛋白的定量表达.结果 MRL/lpr狼疮鼠肾脏的磷酸化PYK2蛋白明显活化,给予姜黄素干预治疗后肾脏的磷酸化PYK2蛋白表达降低.结论 狼疮鼠肾脏PYK2信号转导途径的活化与狼疮肾炎的发病密切相关,姜黄素可以降低PYK2信号转导途径的表达.     

特异性小干扰RNA沉默CHOP对肾小管上皮细胞凋亡的影响

目的:研究C/EBP同源蛋白(CHOP)对肾小管上皮HK2细胞凋亡的影响。方法:采用qPCR法检测急性肾损伤患者及健康对照者血清中CHOP的mRNA水平。体外培养肾小管上皮HK2细胞,随机分为对照组、阴性组和si-CHOP组,si-CHOP组和阴性组分别转染CHOP小干扰RNA(siRNA)和阴性对照siRNA,通过转化生长因子β1(TGF-β1)诱导细胞损伤。MTT法检测细胞的活力,流式细胞术检测细胞的凋亡率, Western blot检测细胞中细胞核抗原Ki-67、增殖细胞核抗原(PCNA)、caspase-3和cleaved caspase-3的蛋白水平。结果:与健康对照者相比,急性肾损伤患者血清中CHOP的表达量显著增加(P0.05);转染CHOP siRNA显著降低肾小管上皮细胞HK2中CHOP的水平,与对照组相比差异具有统计学意义(P0.05)。敲减CHOP的表达显著增加肾小管上皮HK2细胞的活力(P0.05),降低其凋亡率(P0.05),增加Ki-67和PCNA的表达量(P0.05),下调cleaved caspase-3的蛋白水平(P0.05)。结论:在急性肾损伤患者血清中CHOP的水平增加。敲减CHOP表达通过调节增殖和凋亡相关蛋白的表达抑制肾小管上皮HK2细胞的凋亡。     

多发性骨髓瘤本周氏蛋白体外对肾小管上皮细胞转分化作用的研究

目的：体外研究多发性骨髓瘤（MM）患者尿本周氏蛋白（BJP）对肾小管上皮细胞（TEC）的转分化作用以探讨MM肾损害的部分机理。方法：将自MM患者尿中提取的κ和λ型BJP各5例以不同浓度与大鼠NRK52E株TEC共同培养72小时,通过倒置显微镜、透射电镜观察TEC形态学改变;采用细胞免疫组织化学法研究细胞骨架标志：细胞角蛋白-18、波形蛋白、α平滑肌肌动蛋白（α-SMA）表达的改变。结果：培养72小时后,光镜下部分细胞拉长呈梭形;透射电镜下细胞变得肥大,细胞中出现与细胞长轴平行的微丝束和致密体;随BJP的浓度增加,NRK52E细胞角蛋白-18表达率逐渐减少,波形蛋白和α-SMA表达率逐渐增加。结论：BJPκ与BJPλ均有促进NRK52E转分化的作用,且随着BJP浓度增加而增强。     

不同分子量尿毒血清组分对人肾小管上皮细胞CTGF基因和蛋白表达的影响

目的：探讨不同分子量尿毒血清组分对人肾小管上皮细胞结缔组织生长因子（CTGF）基因和蛋白表达的影响。方法:无菌条件下收集40份尿毒症病人血清和20例正常人血清，应用Centricon Plus 20 Centrifugal Filter Devices将尿毒血清分离成分子量 >10 000 D，5 000-10 000 D，<5 000 D 3个组分。应用Western blotting方法检测CTGF的蛋白表达，RT-PCR方法检测CTGF mRNA表达。结果:2.5%-20%浓度尿毒血清组CTGF基因表达均明显高于正常对照组，以10%尿毒血清组最高；分子量 <5 000 D尿毒血清组CTGF基因表达与正常对照组差异无显著，而分子量 5 000-10 000 D和 >10 000 D尿毒血清组CTGF基因表达均高于正常对照组，以分子量 >10 000 D尿毒血清组最高。不同浓度尿毒血清组CTGF蛋白表达均高于正常对照组，且有随着尿毒血清浓度的升高而增高，在不同分子量尿毒血清组中，以分子量 >10 000 D组增高最为显著。结论：尿毒症毒素通过影响人肾小管上皮细胞致纤维化细胞因子CTGF基因和蛋白表达从而在人肾小管-间质纤维化中起重要作用，而以分子量大于 10 000 D的尿毒症毒素在其中起主要作用。     

TNF-α和IFN-γ对肾小管上皮细胞趋化因子表达的影响

目的探讨细胞因子TNF-α和IFN-γ对肾小管上皮细胞趋化因子CXCL9、CXCL10和CXCL11表达的影响。方法分别以TNF-α以及IFN-γ和TNF-α联合作用肾小管上皮细胞HK-2不同时间后,用Real-time PCR和ELISA分别检测CXCL9、CXCL10和CXCL11 mRNA和蛋白水平。用流式细胞术检测淋巴细胞表面CXCR3表达情况,通过趋化实验检测细胞培养上清对淋巴细胞的趋化作用。结果肾小管上皮细胞在TNF-α作用12 h后能够诱导趋化因子CXCL9、CXCL10和CXCL11mRNA表达上调,CXCL9 mRNA的表达在48 h达到高峰,而CXCL10和CXCL11 mRNA表达高峰在12 h;CXCL9、CXCL10和CXCL11蛋白的基础分泌水平均较低,在TNF-α作用12 h后,分泌水平也逐渐升高,CXCL9、CXCL10在48 h时分泌达到高峰,CXCL11分泌高峰在72 h。与TNF-α单独作用组和IFN-γ单独作用组相比,TNF-α和IFN-γ联合作用使肾小管上皮细胞趋化因子CXCL9、CXCL10和CXCL11 mRNA表达和蛋白分泌明显增强(P<0.05)。与新鲜分离的淋巴细胞相比,活化的淋巴细胞表面的CXCR3表达明显升高(P<0.05)。TNF-α以及IFN-γ和TNF-α联合作用HK-2细胞培养上清对活化的淋巴细胞具有明显的趋化作用(P<0.05)且能被抗CXCR3抗体所阻断(P<0.05)。结论细胞因子TNF-α能诱导肾小管上皮细胞趋化因子CXCL9、CXCL10和CXCL11表达,且与IFN-γ联合作用对趋化因子的表达具有协同作用。     

不同常规培养液对人肾小管上皮细胞的影响

目的： 通过4种常规培养液对人肾小管上皮细胞株（HKC）的培养及其细胞表型特征的观察,探讨目前肾小管上皮细胞体外培养存在的有关问题。方法： 采用DMEM（含10%新生牛血清）、DMEM/F12（含5%新生牛血清）、DMEM/F12（含5%胎牛血清）和keratinocyte-SFM（含rEGF和BPE）完全培养液分别进行HKC细胞的体外培养。应用细胞免疫荧光或Western blotting法分别检测传6代细胞cytoketatin-18、E-cadherin、α-SMA和vimentin的表达。结果： HKC细胞经过DMEM（10%新生牛血清）和DMEM/F12（含5%新生牛血清）完全培养液培养3代后,α-SMA和vimentin分别转为强阳性表达,而cytoketatin-18、E-cadherin则分别转为阴性或弱阳性;keratinocyte-SFM完全培养液则具有逆转HKC细胞的cytoketatin-18、E-cadherin阴性转化作用,与此相反,DMEM/F12（含5%胎牛血清）可使这种cytoketatin-18、E-cadherin阳性的HKC细胞发生cytoketatin-18阴性转化。结论： 不论是含血清还是无血清培养液培养的肾小管上皮细胞,均具有体外研究的局限性。     

不同剂量黄芪注射液对人肾小管上皮细胞黏附分子CD146表达的影响

目的:探讨不同剂量黄芪注射液对人肾小管上皮细胞(HK2)黏附分子CD146表达的干预作用。方法:将传代HK2等分为5组,进行培养处理:正常对照组(LG组,只加5.5mmol/L D-葡萄糖),高糖组(HG组,加入25mmol/L D-葡萄糖),黄芪注射液干预组:在HG组中加入不同剂量黄芪注射液,加入2μg/ml者为低剂量组(AML组)、加入20μg/ml者为中剂量组(AMM组)、加入200μg/ml为高剂量组(AMH组)。观察37℃培养24h、48h、72h后,各组HK2形态变化、分别收集各组培养细胞,用Western Blotting检测其CD146蛋白表达。结果:HG组较LG组HK2变长,呈梭形,细胞间连接疏松,间隔增大;黄芪注射液干预各组,细胞形态均较HG组变小变圆,且连接逐渐紧密,AMH组呈堆积生长。HG组CD146表达均较LG组明显增加(P0.01),干预24h、48h、72h,AMM组、AMH组与HG组比较,CD146表达均明显减少(P0.05或P0.01),AML组干预培养72h,CD146的表达亦明显减少(P0.01)。结论:黄芪注射液改善高糖引起的HK2形态改变和降低其CD146表达,对防治DN有积极作用。     

酪氨酸激酶抑制剂对T淋巴细胞生物学特性影响的研究

目的探讨酪氨酸激酶抑制剂（TKI）在体外对T淋巴细胞生物学特性的影响。方法应用尼龙毛柱法分选人外周血T淋巴细胞,加入植物血凝素和抗人CD3单克隆抗体体外培养;运用MTT法检测不同浓度的伊马替尼（imatinjb）、尼罗替尼（nilotib）对T细胞增殖的影响;酶联免疫吸附试验（ELISA）法检测其分泌的细胞因子浓度;通过流式细胞仪检测T细胞表面免疫活性标志;实时荧光定量PCR法检测各组T细胞信号分子P56^lck。mRNA的表达。结果伊马替尼、尼罗替尼对T淋巴细胞增殖活性有抑制作用（P=0）,且呈浓度和时间依赖性;各处理组细胞因子IFN-γ、TNF-α、IL-4、IL-2浓度较对照组低（P=0．03）,IL—10浓度在处理组与对照组无差异（P=0．53）,且表面活性分子CD25和CD69明显减少（P=0．03,P=0．01）,尼戮替尼处理组CD25、CD69表达更低（P=0．05,P=0）;各处理组T细胞信号分子P56^lck。表达水平降低（P=0．03）,而尼罗替尼处理组P56^lck。表达更低（P=0．04）。结论有效治疗浓度的伊马替尼、尼罗替尼在体外可能通过抑制T淋巴细胞受体P56^lck的表达进而抑制T细胞的增殖和活性。     

MG132对高糖条件下肾小管上皮细胞SnoN蛋白表达及纤维化效应的影响

目的:观察蛋白酶体抑制剂MG132对高糖培养条件下肾小管上皮细胞核转录共抑制因子Sno N蛋白表达的影响,探讨MG132减轻高糖状态下肾小管纤维化病变的作用及可能机制。方法:将体外培养的NRK-52E细胞分为正常组(NG)、高糖组(HG)和不同浓度MG132预处理后高糖培养组(HG+MG132),采用免疫荧光双染的方法观察E-钙黏蛋白(E-cadherin)和α-平滑肌肌动蛋白(α-SMA)在肾小管上皮细胞中的表达和分布,用Western blotting方法检测Sno N、Samd泛素化调节因子2(Smurf2)、Arkadia、E-cadherin、α-SMA和Ⅰ型胶原(Col-Ⅰ)等目标蛋白的相对表达量。结果:与NG组相比,HG组肾小管上皮细胞E-cadherin和Sno N表达减少(P0.05),而α-SMA、Col-Ⅰ、Smurf2和Arkadia表达增多(P0.05);与HG组相比,不同浓度MG132预处理肾小管上皮细胞后高糖培养,可见肾小管上皮细胞中Sno N和E-cadherin蛋白表达显著上调(P0.05),而α-SMA和Col-Ⅰ蛋白的表达显著下调(P0.05),并且这种效应呈量效依赖性,但MG132预处理对Smurf2和Arkadia的表达无影响。结论:MG132可对抗高糖介导的肾小管上皮细胞的纤维化效应,其机制可能是通过减少Sno N蛋白的泛素化降解作用实现的。     

脂多糖对人近端肾小管上皮细胞IL-18及其受体复合物表达的影响

观察脂多糖(LPS)对体外培养人近端肾小管上皮细胞IL-18及其受体表达的影响,以初步探讨IL-18在肾小管-间质炎症损伤过程中的作用。以不同浓度LPS(0.01、0.1、1、5、10μg/ml)处理人近端肾小管上皮细胞株(HK-2)24 h、36 h及48 h,然后应用RT-PCR及ELISA测定IL-18及其受体α链(IL-18Rα)和β链(IL-18Rβ)mRNA及蛋白的表达水平变化。静息培养的HK-2细胞表达IL-18 m RNA和蛋白、IL-18Rα和IL-18Rβm RNA,LPS促进HK-2细胞IL-18 mRNA和蛋白的表达及IL-18Rα和IL-18RβmRNA的表达,并呈剂量和时间依赖趋势。肾小管上皮细胞可能既是IL-18的产生者,又是IL-18的靶细胞之一,炎症状态下肾小管上皮细胞通过IL-18自分泌方式参与肾小管-间质的炎症损伤过程。     

IL-4及CD40 mAb对肾小管上皮细胞RANTES表达的影响

目的:观察小鼠肾小管上皮细胞(TEC)在IL-4及CD40激活状态下激活正常T细胞表达和分泌因子(RANTES)分泌的变化。方法:刺激原代培养的小鼠肾小管上皮细胞,检测RANTES的表达,流式细胞仪检测CD40表达。结果:(1)常规培养下,小鼠TEC可表达一定量的CD40,用IL-4刺激TEC 24 h,细胞表面CD40 MFI 显著高于对照组(P<0.01)。(2)常规培养下,小管上皮细胞仅分泌极少量的RANTES(14.78 ng/L±2.20 ng/L),在IL-4刺激或CD40mAb激活后TEC RANTES蛋白分泌分别为43.61±13.73和73.77±4.28,显著高于对照组(P<0.01)。用IL-4刺激肾小管细胞CD40表达的同时,加入纯化的CD40mAb激活CD40受体,TEC RANTES 的合成、分泌显著高于对照组(131.77±41.87,P<0.01),与单纯IL-4刺激组及CD40mAb刺激组比较差异显著(均P<0.01)。(3)用IL-4、CD40mAb及 IL-4+CD40mAb刺激TEC细胞24 h,各刺激组RANTES mRNA表达显著高于对照组(P<0.05)。结论:IL-4及CD40-CD40L共刺激信号可调控RANTES合成及分泌,参与TEC炎症过程。     

IL-2对中子照射后肠上皮细胞生长和凋亡的影响及其机制

目的:观察中子照射对体外培养的IEC-6细胞生长的影响及IL-2对其损伤后增殖和恢复的作用,并进一步探讨IL-2调节受照射肠上皮细胞生长的相关机制。方法:单独用IL-2(1×105U/L)或同时施加JAK1激酶阻断剂(A77-1726)处理受4Gy中子照射的IEC-6细胞,并于照后10、15、30min和1、3、6、12、24、48及72h,用MTT比色法和流式细胞术检测受照射后IEC-6细胞的增殖活力和死亡方式的改变。以免疫细胞化学染色和Western blot检测IEC-6细胞上IL-2Rβ的表达和JAK1活化情况。结果:4Gy中子照射后24h,IEC-6细胞的增殖活力明显降低;而IL-2处理组该细胞的增殖活力有显著提高(P<0.05)。受中子照射的IEC-6细胞经IL-2作用24h,其凋亡率明显降低(P<0.05),而坏死率变化不明显。以IL-2刺激中子照射的IEC-6细胞后,于10及15min可见JAK1发生明显磷酸化活化,24h时IL-2Rβ的表达明显增多。同时应用A77-1726和IL-2处理受中子照射的IEC-6细胞后,其增殖活力明显低于单纯IL-2处理组。结论:IL-2可促进受中子照射的IEC-6细胞增殖,具有抗辐射作用。IL-2Rβ和JAK1活化参与了IL-2对中子损伤的IEC-6细胞生长的调控。     

Regulation and production of IL-8 by human proximal tubular epithelial cells in vitro

A number of inflammatory kidney diseases are associated with interstitial nephritis and influx of leucocytes in the renal interstitium. Potentially the influx of neutrophils in the interstitium may be induced by the chemotactic cytokine IL-8. In the present study we have analysed the production of IL-8 by cultured human proximal tubular epithelial cells (PTEC) in response to a number of proinflammatory cytokines. Primary cell lines of proximal tubular epithelium obtained from ten different kidneys, and cultured under serum-free conditions, were found to produce IL-8 to different degrees from not detectable levels up to 10·8±1·5 ng IL-8 per 1×10⁵ cells in 72 h. Gel filtration chromatography of PTEC supernatant indicated that the size of IL-8 of PTEC is 15·1 and 8·1 kD, and is chemotactically active for polymorphonuclear neutrophils (PMN). Addition of 0·5 ng/ml rIL-1α or 1000 U/ml recombinant tumour necrosis factor-alpha (TNF-α) to the culture media of PTEC induced an up-regulation of IL-8 production up to 6·3-fold and 3·0-fold, respectively. The up-regulation by IL-1α and TNF-α was dose- and time-dependent. In contrast, 500 U/ml recombinant interferon-gamma (rIFN-γ) down-regulated the production of IL-8 3·4-fold. Northern blot analysis showed that IL-1α and TNF-α increased the expression of IL-8 mRNA, whereas IFN-γ reduced IL-8 mRNA expression. Taken together, these experiments indicate that human PTEC are a potential source of IL-8 in the kidney, and that IL-8 produced in the proximal tubule can be induced by various proinflammatory cytokines.     

Stimulation of the expression and the enzyme activity of aminopeptidase N/CD13 and dipeptidylpeptidase IV/CD26 on human renal cell carcinoma cells and renal tubular epithelial cells by T cell-derived cytokines, such as IL-4 and IL-13.

Aminopeptidase N (APN) and dipeptidylpeptidase IV (DPIV) are transmembrane type II molecules widely distributed in mammalian tissues. In recent years, the interest in cell surface peptidases has increased considerably because, among other things, several reports indicate roles of ectopeptidases in tumour cell metastasis. Investigations into the regulation of APN and DPIV on tumour cells are rare. We report, for the first time, that IL-4 and IL-13 can up-regulate protein expression as well as enzymatic activity of both the peptidases on renal carcinoma cells and renal tubular epithelial cells in culture. The analysis of mRNA by competitive polymerase chain reaction (PCR) confirmed our results with respect to the APN increase at the level of gene expression. IL-1 beta and tumour necrosis factor-alpha (TNF-alpha) augmented the IL-4-induced effect with respect to APN but not to DPIV. A 5-day incubation with interferon-gamma (IFN-gamma) increased protein expression, especially of APN and, to a lesser extent, also of DPIV, whereas no significant increase in enzymatic activity could be observed. Small concentrations of transforming growth factor-beta 1 (TGF-beta 1) inhibit the expression and enzyme activity of DPIV. IL-6, IL-7, IL-10 and granulocyte-macrophage colony-stimulating factor (GM-CSF) have been found to be without any effect on APN and DPIV. For a prospective therapeutic regimen with T cell-derived cytokines it has to be considered that--besides their effect on tumour cell growth--cytokines might affect surface ectopeptidases involved in tumour cell adhesion processes. The inhibition of APN and DPIV could be a new approach to suppression of cancer spread.     

IL-27 regulates IL-4-induced chemokine production in human bronchial epithelial cells

IL-4 coordinates the Th2-type immune response in inflammatory diseases such as asthma. IL-27 can inhibit the development of both Th2 and Th1 cells. However, IL-27 can also drive naïve T cells to differentiate toward the Th1 phenotype. In this study, we investigated the effects of IL-27 on the activation of IL-4-induced human bronchial epithelial cells (BEAS-2B). Compared to controls, both IL-4 and IL-27 (25–100 ng/mL) increased the concentrations of CCL2 and IL-8 in a dose-dependent manner. However, compared to cells stimulated individually with IL-4 or IL-27, treatment with a combination of both cytokines reduced CCL2 and IL-8 concentrations in a dose- and time-dependent manner. IL-4 increased the activation of p38 MAPK, ERK1/2, STAT6 and NF-κB, while IL-27 increased the activation of p38 MAPK and ERK1/2 but not STAT6 and NF-κB. Compared to IL-4-stimulated cells, cells treated with both IL-27 and IL-4 displayed decreased activation of STAT6 and NF-κB but not ERK1/2 and p38 MAPK. Taken together, these results suggest that IL-27 plays a pro-inflammatory role when administered alone but downregulates bronchial epithelial cell activation when combined with IL-4. Therefore, IL-27 may be an interesting target for the treatment of Th2 inflammatory diseases.     

IL-2 receptor gene expression and IL-2 production by human preterm newborns' cells.

IL-2 receptor (IL-2R) gene expression in human umbilical cord blood mononuclear cells (CBMC) of preterm and term newborns was examined following stimulation for 18 h with phytohaemagglutinin (PHA) and compared with that of adult peripheral blood mononuclear cells (PBMC; mothers and control group). mRNA for IL-2R could not be detected in CBMC of preterm infants, whereas the mRNA levels for IL-2R found in full term neonates were similar to those observed in PBMC of adults. IL-2 activity in conditioned medium (CM) of mononuclear cells stimulated with either optimal or suboptimal PHA concentrations for 24 h and 48 h was also determined. At 24 h of stimulation, IL-2 activity found in CM obtained from CBMC of preterm and term newborns was significantly higher than that found in CM of adults' PBMC. A further enhancement of IL-2 activity (six to eight times) was observed in CM of preterm and term cells stimulated for 48 h, whereas no significant difference was found in IL-2 activity in CM from adult cells tested at the two incubation periods. The present findings may provide an additional explanation for the impaired function of the immune system, and the high susceptibility to infections observed in preterm newborns.     

Escherichia coli-induced expression of IL-1 alpha, IL-1 beta, IL-6 and IL-8 in normal human renal tubular epithelial cells

The aim of the present study was to investigate whether the IL-1 family cytokines, in addition to IL-6 and IL-8, could be induced in normal human cortical epithelial cells in response to bacterial stimuli. Human renal tissue was obtained from 9 patients undergoing elective tumour nephrectomy. Renal cortical epithelial cells of tubular origin were prepared from the unaffected tissue. The proximal tubular cells were stimulated for 2, 6 and 24 h with a heat-inactivated pyelonephritogenic Escherichia coli strain DS-17. Cultured unstimulated tubular cells served as controls. IL-1 alpha, IL-1 beta, IL-1 receptor antagonist, IL-6, IL-8, IL-10, TNF-alpha, G-CSF and GM-CSF were analysed using immunohistochemistry at the single cell level. The nonstimulated cells were found to express low levels of IL-6 and IL-8 (mean value < 3% of total cells). In contrast, E. coli exposure resulted in significantly increased incidences of IL-6 and IL-8 expressing cells (mean values approximately 18% of total cells) peaking within two hours of stimulation (P < 0.008 and P < 0.02 versus non-stimulated cells, respectively). A gradual decrease was thereafter observed at 6 and 24 h, respectively, although persistently higher compared to controls. A different kinetic response was found for IL-1 alpha, IL-1 beta and IL-1 receptor antagonist-expressing cells, which peaked 24 h after E. coli stimulation (mean values 3--10%) (P < 0.008, P < 0.02, P < 0.02 versus non-stimulated cells, respectively). Low levels of TNF-alpha and GM-CSF were found in 3 of the 9 donated epithelial cells, peaking at 2 h, and IL-10 and G-CSF producing cells in 1 patient each. In conclusion we found that heat-inactivated pyelonephritic E. coli induced a proinflammatory cytokine response in the normal human proximal tubular cells including the IL-1 family, IL-6 and IL-8.