穿心莲内酯对IL-6诱导的非小细胞肺癌细胞侵袭转移的影响及机制

目的探讨穿心莲内酯(AD)对白细胞介素(IL)-6诱导的非小细胞肺癌细胞侵袭转移的影响及机制。方法采用MTT法检测不同浓度AD和IL-6对人肺腺癌A549细胞增殖活性的影响;Transwell小室实验检测AD对IL-6诱导的A549细胞侵袭的影响;Western印迹检测A549细胞中转移相关蛋白基质金属蛋白酶(MMP)-9、上皮间质转化(EMT)相关蛋白E-钙黏附蛋白(E-cadherin)、波形蛋白(Vimentin)及核因子(NF)-κB信号通路相关蛋白磷酸化NF-κB抑制蛋白(p-IκBα)、IκBα的表达。结果 0.5μmol/L、1.0μmol/L和3.0μmol/L低浓度AD和20μg/L、50μg/L和100μg/L IL-6对A549细胞的增殖的无明显影响。给予20μg/L浓度的IL-6处理后,A549细胞的侵袭能力明显增强,A549细胞中MMP-9、Vimentin、p-IκBα蛋白表达升高,而E-cadherin和IκBα蛋白表达降低;而给予0.5μmol/L、1μmol/L和3μmol/L AD处理后,IL-6对A549细胞的上述作用明显减弱,且呈现一定的浓度依赖性。结论 AD可抑制IL-6诱导的非小细胞肺癌细胞侵袭转移,其作用机制可能与抑制NF-κB信号通路的活化有关。     

阿奇霉素对烟曲霉刺激A549细胞分泌IL-6和IL-8的影响

目的 观察阿奇霉素对烟曲霉孢子刺激A549细胞、支气管上皮细胞分泌IL-6和IL-8的影响.方法 制备烟曲霉孢子侵袭A549细胞、支气管上皮细胞体外模型,分别加入不同浓度(o.5 mg/2.5 mg)阿奇霉素和地塞米松培养24 h,以酶联免疫吸附测定(ELISA)法检测离心液中IL-6和IL-8的水平,比较不同药物浓度对两种细胞因子水平的影响.结果 孢子组释放IL-6/IL-8浓度明显高于对照组;在阿奇霉素组、地塞米松组,支气管上皮细胞、A549细胞释放IL-6/IL-8浓度明显低于孢子组.结论 阿奇霉素和地塞米松可以抑制烟曲霉孢子所致的A549细胞、支气管上皮释放IL-6和IL-8,减轻机体炎症反应.     

肾小球系膜细胞白细胞介素-6基因表达与白细胞介素-13的关系

目的探讨白细胞介素-13(IL-13)对于体外培养大鼠系膜细胞白细胞介素-6(IL-6)分泌及其基因表达的影响,以研究IL-13对肾小球疾病状态下肾脏系膜细胞炎症反应的抑制作用。方法用酶联免疫吸附法(ELISA)测定系膜细胞IL-6分泌量,用逆转录聚合酶链反应(RT-PCR)检测系膜细胞IL-6mRNA表达。结果正常培养条件下系膜细胞IL-6mRNA表达及IL-6分泌水平较低,脂多糖(LPS)可刺激系膜细胞IL-6mRNA的表达及IL-6分泌水平,而IL-13则呈剂量依赖性地抑制LPS诱导的系膜细胞IL-6分泌及其mRNA表达。结论IL-13抑制LPS诱导的体外培养的系膜细胞IL-6产生,故可能对于肾小球疾病状态下肾脏的系膜细胞炎症反应具有抑制作用。     

哮喘患者诱导痰中IL-17A、IL-8及MMP-9水平变化及糖皮质激素对其的影响

目的探讨哮喘患者气道炎症特点及糖皮质激素的作用机制。方法将33例哮喘患者（哮喘组）按病情程度分为轻、中度19例及重度14例,予规范吸入糖皮质激素治疗4周,行诱导痰炎性细胞分类并计数,采用ELISA法检测痰上清液炎性介质白细胞介素-17A（IL-17A）、IL-8、基质金属蛋白酶-9（MMP-9）水平,并与15例查体健康者（对照组）进行比较。对诱导痰细胞分类、1秒钟用力呼气量占预计值百分比（FEVl％）及炎性介质水平进行相关分析。结果重度哮喘者诱导痰中性粒细胞、嗜酸性粒细胞比值及上清液IL-17A、IL-8、MMP-9水平显著高于对照组及轻、中度者;轻-中度者除MMP-9无显著升高外,余各指标均显著高于对照组（P均〈0．01）。诱导痰中性粒细胞及嗜酸性粒细胞比值与FEV1％呈显著负相关;中性粒细胞比值与IL-8、MMP-9呈正相关;IL-17A水平与中性粒细胞比值、IL-8呈正相关。糖皮质激素治疗后重度者中性粒细胞、嗜酸性粒细胞比值及MMP-9水平仍显著高于轻-中度者。结论中性粒细胞浸润性气道炎症是重度持续性哮喘的重要特征;IL-17A、IL-8与MMP-9可能在其中发挥重要作用。吸入糖皮质激素能抑制炎症细胞的趋化效应,阻止炎症释放,稳定细胞溶酶体膜,减轻组织损伤。     

透明质酸对游离脂肪酸引起的人主动脉血管平滑肌细胞表达IL-6、IL-8和TNF-α的影响

目的 探讨透明质酸(HA)对游离脂肪酸(FFA)引起的人主动脉血管平滑肌细胞(HA-VSMC)表达白细胞介素6(IL-6)、IL-8和肿瘤坏死因子α(TNF-α)的影响。方法 培养HA-VSMC,用不同浓度(0、100、200、400μmol/L)FFA和不同浓度FFA+高分子量HA(HMW-HA)或低分子量HA(LMW-HA)处理细胞24、48 h。噻唑蓝法检测FFA和FFA+HA对HA-VSMC存活率的影响;Ed U染色检测细胞增殖活性;酶联免疫吸附法检测培养上清IL-6、IL-8和TNF-α含量;实时荧光定量PCR和Western blot检测IL-6、IL-8和TNF-αmRNA及蛋白表达水平。结果(1)FFA在400μmol/L内呈浓度依赖性诱导HA-VSMC增殖;(2)HMW-HA、LMW-HA均对FFA诱导的HA-VSMC增殖有抑制作用,且HMW-HA抑制作用强于LMW-HA;(3)FFA显著促进HA-VSMC IL-6、IL-8和TNF-α的分泌,且有明显的时间和浓度依耐性;HA可以抑制上述作用;(4)实时荧光定量PCR和Western blot结果显示,FFA+HMWHA组、FFA+LMW-HA组IL-6、IL-8、TNF-αmRNA及蛋白表达水平均低于FFA组(均P0.01),其中FFA+HMW-HA组又低于FFA+LMW-HA组(P0.01)。结论 (1)FFA诱导HA-VSMC IL-6、IL-8、TNF-αmRNA和蛋白表达升高;(2)HA对FFA引起的HA-VSMC IL-6、IL-8和TNF-α的表达有抑制作用,且HMW-HA抑制效果强于LMW-HA。     

HCMV感染对人原代星形胶质细胞IL-6和IL-8表达的影响

目的观察人巨细胞病毒(HCMV)感染时人原代星形胶质细胞分泌的IL-6和IL-8的表达变化。方法分离纯化人原代星形胶质细胞并用免疫荧光法鉴定纯度。用HCMV感染原代星形胶质细胞制作HCMV感染模型,采用RT-PCR及免疫荧光法检测感染后星形胶质细胞中的即刻早期(IE)mRNA和蛋白的表达(进行模型鉴定)。RT-PCR及Western blot法检测正常培养和感染HCMV的人原代星形胶质细胞中IL-6和IL-8 mRNA和蛋白的表达。结果 HCMV能够感染人原代星形胶质细胞。正常培养的人原代星形胶质细胞能够表达IL-6 mRNA和蛋白,但不表达IL-8;HCMV感染初期的人原代星形胶质细胞中IL-6 mRNA和蛋白均表达增加,IL-8表达被激活(P均<0.05),而感染后期两种因子的表达明显下调。结论 HCMV感染能够诱导人原代星形胶质细胞IL-6和IL-8的表达异常。     

黄芪多糖对LPS损伤小肠上皮细胞的保护作用

目的:探讨黄芪多糖(APS)在内毒素-脂多糖(LPS)损伤小肠上皮细胞(IEC-6)中的作用机制及对细胞因子和核因子-κB(NF-κB)表达的影响.方法:以小肠上皮细胞株IEC-6为研究对象, 将培养的细胞分为6组: 对照组、LPS组、LPS APS 50 mg/L组、LPS APS 100 mg/L组、LPS APS 200 mg/L组和LPS APS 500 mg/L组. 采用RT-PCR法检测细胞因子TNF-α和IL-8 mRNA的表达, 采用凝胶电泳迁移率法分析NF-κB蛋白活性.结果: LPS损伤IEC-6细胞后, TNF-α, IL-8 mRNA水平和NF-κB蛋白定量表达均升高, 均显著高于对照组(TNF-a: 1.26±0.06 vs 0.65±0.05, IL-8 mRNA: 1.19±0.05 vs 0.57±0.06, NF-kB: 2.76±0.07 vs 0.07±0.03, P均<0.01). 而黄芪多糖呈浓度和时间依赖性地抑制LPS诱导IEC-6细胞分泌的TNF-α, IL-8等细胞因子的mRNA的表达水平(P<0.01), 并能降低NF-κB的表达活性(P<0.01).结论:APS具有抑制LPS刺激IEC-6细胞产生的TNF-α, IL-8炎性因子的作用, 并能降低NF-κB的表达活性, 其对LPS所致的肠道损伤具有保护作用.     

乌司他丁对重度烧伤患者血清TNF-α、IL-6、IL-8水平的影响

目的观察乌司他丁对严重烧伤患者血清肿瘤坏死因子-α（TNF-α）、IL-6、IL-8水平的影响。方法 50例严重烧伤患者随机分为A、B组,各25例。A组按常规创面处理,给予营养支持、抗休克治疗;B组在常规创面处理、营养支持、抗休克治疗的基础上加用乌司他丁治疗。分别于治疗前及治疗后第3、7天取外周静脉血,采用ELISA法检测血清TNF-α、IL-6、IL-8。同时与20例健康体检者作为对照（C组）。结果 A、B组血清TNF-α、IL-6、IL-8水平显著高于C组（P均〈0.05）;治疗前A、B组血清TNF-α、IL-6、IL-8水平比较,P均〉0.05;治疗后第3、7天B组低于A组（P均〈0.05）。结论乌司他丁能抑制烧伤患者血清TNF-α、IL-6、IL-8的释放,从而有效降低由烧伤引发的炎症反应。     

IL-6联合sIL-6R对人甲状腺细胞增殖及相关基因表达的影响

目的 探讨白细胞介素-6(IL-6)联合可溶性IL-6受体(sIL-6R)对人甲状腺细胞增殖及相关基因表达的影响.方法 通过手术标本获得甲状腺组织,采用甲状腺细胞培养技术,提取并培养甲状腺细胞.以不同浓度(0、1、5、10、20 μg/L)的IL-6分别联合sIL-6R 100μg/L干预细胞24、48 h,予以IL-6单克隆抗体进行阻断.以MTT法检测IL-6干预后的细胞活力,并在显微镜下观察细胞形态学变化;以RT-PCR测定IL-6、IL-6受体及糖蛋白130的表达,实时定量PCR检测IL-6干预后甲状腺细胞的钠-碘转运体(NIS)、甲状腺过氧化物酶(TPO)、甲状腺球蛋白(TG)、促甲状腺激素受体(TSHR)基因的表达.结果 甲状腺细胞表达IL-6、糖蛋白130,但几乎不表达IL-6受体.IL-6联合sIL-6R培养24、48 h后,甲状腺细胞活力显著增加(F=65.28、78.47;P均＜0.05),而使用IL-6单克隆抗体进行阻断,发现随着IL-6单克隆抗体浓度的增加,甲状腺细胞活性亦显著下降(F=60.15,P＜0.05);随着IL-6浓度的增加,甲状腺细胞数量越多,体积越大.IL-6能够抑制NIS、TPO、TG基因的表达(t=6.92～12.12,P均＜0.05),而对TSHR基因无明显影响.结论 IL-6联合sIL-6R能够促进甲状腺细胞增殖,同时也能够抑制甲状腺相关基因的表达.     

幽门螺杆菌cagⅡ对胃上皮细胞IL-8基因转录的影响机制

【目的】探讨Hp cagⅡ对胃上皮细胞IL-8基因转录的影响及信号传导机制。【方法】构建cagⅡ基因位点缺失Hp突变株及带有IL-8报告基因的人胃癌细胞系L5F11,用液体闪烁计算仪测定荧光素酶(IL-8转录)活性,用ELISA法测定IL-8蛋白浓度。【结果】所有Hp突变株诱导荧光素酶活性与IL-8蛋白浓度较亲代菌株26695均降低(0.13±0.01vs0.59±0.05×10~6cmp,P<0.01;0.73±0.13vs2.22±0.65ng/ml,P<0.05)。PTK抑制剂herbimycin A不仅抑制Hp诱导的荧光索酶活性(0.71±0.18vs1.51±0.23×10~6cpm,P<0.05),而且抑制IL-8蛋白表达(0.83±0.41vs3.22±0.59ng/ml,P<0.05),但herbimycin A对TNF_α诱导的荧光素酶活性及IL-8蛋白表达均无影响(P均>0.05);PKA抑制剂H7抑制TNFa诱导的荧光素酶活性(0.74±0.16vs2.62±0.26×10~6cpm,P<0.001)及IL-8蛋白表达(1.45±0.38vs4.12±0.43ng/ml,P<0.01),而对Hp诱导的荧光素酶活性无影响(P>0.05)。【结论】Hp cagⅡ中的多个基因能够调节胃上皮细胞IL-8基因转录,且这一作用主要经蛋白酪氨酸激酶途径。     

Role of mechanical stretching and lipopolysaccharide in early apoptosis and IL-8 of alveolar epithelial type II cells A549

ObjectiveTo investigate the effects of mechanical stretching and lipopolysaccharide (LPS) on the early apoptosis and IL-8 production of alveolar epithelial type Π cells A549.MethodsThe experimental matrix consisted of three integrated studies. In the first study, A549 cells were subjected to different stretching strain frequency and duration time to see the effects on the early apoptosis. In the second study, A549 cells were subjected to mechanical stretch (15% 4 h, 0.5 Hz) and LPS (1 or 100 ng/mL) to see whether mechanical strain and LPS also have an addictive effect on the early apoptosis. In the third study to investigate whether this addictive effect could be induced by LPS and mechanical stretch on IL-8 production, A549 cells were subjected to LPS (100 ng/mL) and mechanical strain (15%, 0.5 Hz, 4 h). Real time PCR and enzyme linked immunosorbent assay were used to measure mRNA and protein level of IL-8. The early apoptosis was detected by flow cytometry.ResultsMechanical stretch induced the early apoptosis in a force and frequency and time-dependent manner. In the presence of LPS, mechanical stretch enhanced LPS-induced early apoptosis, especially in 100 ng/mL LPS group compared with 1 ng/mL LPS and the control group. Mechanical stretch increased IL-8 production and enhanced LPS-induced IL-8 screation both in mRNA and protein levels.ConclusionsMechanical stretch can induce the early apoptosis and IL-8 secretion. Mechanical stretch and LPS have an addictive effect on the early apoptosis and IL-8 production in alveolar type 2 cells, which is one of the mechanisms of ventilator-induced lung injury.     

Effect of formoterol and salmeterol on IL-6 and IL-8 release in airway epithelial cells

Beta(2)-adrenoceptors are widely distributed and occur on airway epithelial cells. The aim of this study was to find out whether the two long-acting beta(2)-agonists formoterol and salmeterol influence interleukin-6 (IL-6) and -8 (IL-8) release from airway epithelial cells in vitro. A549 cells and primary bronchial epithelial cells (PBEC) were stimulated with organic dust from pig barns. Non-stimulated and dust-stimulated cells were incubated for 24h with formoterol or salmeterol (10(-13)-10(-6)M) and the release of IL-6 and IL-8 into the medium was assessed by ELISA technique. Propranolol (10(-5)M) or sotalol (10(-3)M) were used to block the beta(2)-agonist mediated effects. Formoterol and salmeterol both induced enhancement of IL-6 and IL-8 release and added to the effect of organic dust. This enhanced release was blocked by a beta-blocker in PBEC but not in A549 cells. To our knowledge, this is the first time beta(2)-agonists have been shown to stimulate IL-6 release from airway epithelial cells. The results indicate different mechanisms of beta(2)-agonist action in bronchial and alveolar epithelial cells. Furthermore, our results indicate that A549 cells do not possess functional beta(2)-adrenoceptors.     

Effects of N-acetylcysteine and ambroxol on the production of IL-12 and IL-10 in human alveolar macrophages

BACKGROUND: N-acetylcysteine (NAC) and ambroxol (AMB) have recently been proposed as possible therapeutic agents in the treatment of pulmonary disorders. IL-12 plays an important role in host resistance to infection and the development of Th-1 cells. In contrast, IL-10 is involved in anti-inflammatory and immunoregulatory mechanisms. OBJECTIVE: We investigated the effects of NAC and AMB on secretions of IL-12 and IL-10 from human alveolar macrophages. METHODS: Alveolar macrophages were obtained from 7 healthy nonsmokers by bronchoalveolar lavage. The cells were first incubated with either NAC or AMB for 2 h and then cultured in lipopolysaccharide (LPS) solution for 24 h. IL-12 and IL-10 secretions were measured by ELISA. RESULT: Both NAC and AMB enhanced LPS-induced secretion of IL-12. NAC also enhanced LPS-induced IL-10 secretion, while AMB did not. The ratio IL-12/IL-10 secretion was increased by AMB, but NAC did not affect it. CONCLUSIONS: The results suggest that NAC enhances inflammatory and immune responses and prevents excessive responses reciprocally, through keeping local balance of IL-12 and IL-10 production in alveolar macrophages at inflammatory sites of bacterial pneumonia. AMB appears to strengthen inflammatory responses and cell-mediated immunity, facilitating the development of Th-1 cells, through shifting the local balance to IL-12 dominance.     

Interleukin (IL)-17 promotes macrophages to produce IL-8, IL-6 and tumour necrosis factor-alpha in aplastic anaemia

Aplastic anaemia (AA) is thought to be an autoimmune-mediated disease with active destruction of haematopoietic cells through a T helper type 1 (Th1) cell response. Interleukin (IL)-17 is a potent proinflammatory cytokine produced by activated memory T cells. Recent studies indicate that IL-17 might be an essential effector cytokine in the T-cell mediated autoimmune process. It can drive the production of tumour necrosis factor-α (TNF-α), IL-1 β, IL-6 and IL-8 by a variety of cells. The present study investigated the genetic and protein expression of IL-17 in patients with AA. The effect of IL-17 on IL-6 and IL-8 production by macrophages was also studied. AA patients showed an elevated expression of IL17A mRNA in bone marrow mononuclear cells and peripheral blood mononuclear cells. Higher IL-17 in bone marrow and peripheral blood plasma was also observed in AA patients compared with normal controls. IL-17 induced the production of IL-6 and IL-8 by macrophages both from patients with AA and normal controls. IL-17 stimulation also resulted in the production of TNF-α. These results suggested that elevated expression of IL-17 and IL-17-induced IL-6, IL-8 and TNF-α may be involved in the mechanisms of AA.     

白细胞介素-1β和白细胞介素-6对妊娠相关血浆蛋白-A表达的影响

目的探讨炎性因子白细胞介素-1β(interleukin-1β,IL-1β)、白细胞介素-6(interleukin-6,IL-6)对人冠状动脉平滑肌细胞(human coronary artery smooth muscle cell,HCASMC)表达妊娠相关血浆蛋白-A(pregnancy-associated plasma pro-tein-A,PAPP-A)的影响。方法应用20μg/L的IL-1β、10μg/L的IL-6各自刺激HCASMC,共同培养0、2、4、8、243、6 h后收集细胞。应用不同浓度的IL-1β(0、5、20、40μg/L)I、L-6(0、5、10、50μg/L)刺激HCASMC,共同培养6 h后收集细胞。应用实时定量聚合酶链反应的方法检测细胞内PAPP-A基因的表达量。结果在同剂量IL-1βI、L-6刺激下,PAPP-A的表达量在2 h时就开始发生上调,8 h达高峰,而后开始下降;在不同剂量IL-1βI、L-6刺激下,PAPP-A的表达量在实验剂量范围内随着剂量的加大呈上升趋势(IL-1β:r=0.972,P=0.000;IL-6:r=0.941,P=0.000)。结论炎性因子IL-1βI、L-6能促进HCASMC中斑块稳定相关标记物PAPP-A的表达,可能是炎症在急性冠状动脉综合征发生发展中的重要作用机制之一。     

Dexamethasone plus retinoids decrease IL-6/IL-6 receptor and induce apoptosis in myeloma cells

Interleukin 6 (IL-6) is the most important known growth factor for multiple myeloma, and IL-6 signalling pathways are potential targets for therapy. We hypothesized that interfering with the IL-6 signalling pathway at more than one level would be more effective than a single block in inhibiting proliferation of myeloma cells. Accumulating data support the concept that glucocorticoids down-regulate IL-6, whereas retinoic acid derivatives (RA) down-regulate IL-6R in myeloma. We found that all- trans RA (ATRA), 13- cis -RA and 9- cis -RA each similarly inhibited growth of RPMI 8226 myeloma cells and that addition of dexamethasone (DEX) added to RA growth inhibition. The major effects of retinoids were to reduce the proliferative fraction and induce apoptosis whereas DEX increased the apoptotic fraction. When combined, apoptosis was enhanced. Effects of RA + DEX were also least able to be overcome by exogenous IL-6. RA decreased IL-6R levels and addition of DEX to RA delayed recovery of IL-6R levels compared with RA alone. Since RPMI 8226 cells have undetectable IL-6, we investigated U266B1 cells and found that RA and DEX decreased both IL-6 secretion and IL-6 RNA levels. Mechanistically, IL-6R down-regulation by RA was enhanced by DEX, whereas IL-6 protein and RNA levels were reduced by DEX and by RA. In summary, combinations of RA + DEX were not only more effective in inhibiting myeloma cells growth by the dual mechanisms of decreasing proliferative fraction and increasing apoptotic fraction, but were also less able to be overcome by IL-6.     

Extracellular forms of IL-37 inhibit innate inflammation in vitro and in vivo but require the IL-1 family decoy receptor IL-1R8

Similar to IL-1α and IL-33, IL-1 family member IL-37b translocates to the nucleus and is associated with suppression of innate and adaptive immunity. Here we demonstrate an extracellular function of the IL-37 precursor and a processed form. Recombinant IL-37 precursor reduced LPS-induced IL-6 by 50% (P < 0.001) in highly inflammatory human blood-derived M1 differentiated macrophages derived from selective subjects but not M2 macrophages. In contrast, a neutralizing monoclonal anti–IL-37 increased LPS-induced IL-6, TNFα and IL-1β (P < 0.01). The suppression by IL-37 was consistently observed at low picomolar but not nanomolar concentrations. Whereas LPS induced a 12-fold increase in TNFα mRNA, IL-37 pretreatment decreased the expression to only 3-fold over background (P < 0.01). Mechanistically, LPS-induced p38 and pERK were reduced by IL-37. Recombinant IL-37 bound to the immobilized ligand binding α-chain of the IL-18 receptor as well as to the decoy receptor IL-1R8. In M1 macrophages, LPS increased the surface expression of IL-1R8. Compared with human blood monocytes, resting M1 cells express more surface IL-1R8 as well as total IL-1R8; there was a 16-fold increase in IL-1R8 mRNA levels when pretreated with IL-37. IL-37 reduced LPS-induced TNFα and IL-6 by 50–55% in mouse bone marrow-derived dendritic cells, but not in dendritic cells derived from IL-1R8–deficient mice. In mice subjected to systemic LPS-induced inflammation, pretreatment with IL-37 reduced circulating and organ cytokine levels. Thus, in addition to a nuclear function, IL-37 acts as an extracellular cytokine by binding to the IL-18 receptor but using the IL-1R8 for its anti-inflammatory properties.IL-37, previously known as IL-1 family member 7, broadly reduces innate inflammation as well as acquired immune responses (1). In human peripheral blood mononuclear cells (PBMCs), a knockdown of endogenous IL-37 results in increased production of LPS- as well as IL-1β–induced cytokines (2). Mice transgenic for full-length human IL-37 (IL-37tg) are protected against LPS-induced systemic inflammation (2), chemical colitis (3), metabolic syndrome (4), and acute myocardial infarction (5). IL-37tg mice also have suppressed immune responses following challenge by specific antigen (6). We believe that full-length IL-37 expressed in the transgenic mice is processed extracellularly.In mouse macrophages stably transfected with human IL-37, ∼20% of IL-37 translocates to the nucleus (7), which is associated with decreased cytokine production (2, 7). However, in the presence of a caspase-1 inhibitor, there is no translocation to the nucleus and no reduction in LPS-induced cytokines (7). Mutation of aspartic acid at the caspase-1 cleavage position 20 to alanine also results in failure to translocate to the nucleus and loss of the suppression of cytokine production (8). Thus, as with IL-1α and IL-33, IL-37 is the third member of the IL-1 family that translocates to the nucleus and affects cellular responses. Nevertheless, it remains unclear whether the reduction in cytokines in vitro or in vivo is due solely to nuclear translocation of IL-37.Support for an extracellular function for IL-37 comes from early studies reported over 10 y ago that demonstrated binding of IL-37 to the α-chain of IL-18 receptor (IL-18Rα). We therefore hypothesized that extracellular IL-37 can function through the IL-18Rα surface receptor to mediate its anti-inflammatory effects but that a negative or decoy receptor would be required. The candidate decoy receptor would likely be IL-1R8 [formerly, single IgG IL-1–related receptor (SIGIRR)] because, similar to IL-18BP, IL-1R8 has only a single Ig domain and is known for providing a brake on inflammation (9). In the present study, we have characterized the function of full-length recombinant IL-37b in inhibiting inflammation in vitro and in vivo and the role of IL-1R8.