Activation of the gp130 signaling pathway by monoclonal antibodies directed against the gp130 molecule

Six cytokines of the interleukin (IL)-6 family involved in various inflammatory or tumoral diseases share the same gp130 signal transducer chain. We made a panel of anti-gp130 monoclonal antibodies (mAb) to study the structure and function of the gp130 molecule. These mAb recognized different epitopes of the gp130 that we called A to J. Most of the mAb were found to be inhibitors and we studied whether some of them could also induce gp130 activation. When used alone, none of them was able to initiate the proliferation of IL-6-dependent cell lines. However, some particular associations of the mAb were able to induce a proliferative response. mAb B1 could activate the lines in association with F1 or with I2 but not with I1, which in ELISA was similar to I2. In contrast mAb B2, which in ELISA appeared to be very similar to B1, was able to activate the cells in association with I1 but not with F1 or I2. Two other mAb belonging to specificities A and C were found to be activators either in association with I1 only, or with I1 or B2, respectively. These associations of mAb appeared to be nearly as potent activators as IL-6 itself. Although we still have no precise idea of the mechanisms involved, they are interesting tools to study the molecular interactions leading to gp130 activation and, from a practical point of view, valuable growth factors of hematopoietic stem cells.     

IL-6 and soluble IL-6 receptors (sIL-6R and sgp130) in human pleural effusions: massive IL-6 production independently of underlying diseases

IL-6, soluble IL-6 receptor (sIL-6R) and soluble gp130 (sgp130) levels were measured in sera and pleural effusions from 42 patients with metastatic carcinoma, non-Hodgkin's lymphoma, tuberculosis, cardiac failure and miscellaneous diseases. Pleural IL-6 levels measured by ELISA were very high in all patient groups (mean 34.8 ± 15.3 ng/ml) without significant difference according to diseases. IL-6 was shown to be biologically active in a proliferative assay. Serum IL-6 levels were low (0.049 ± 0.014 ng/ml) and did not correlate with pleural fluid levels. Pleural IL-6 levels correlated with the number of polymorphonuclear cells in pleural fluid (P< 0.03). Pleural sIL-6R levels (76 ± 8 ng/ml) were always lower than serum levels (196 ± 12 ng/ml; P< 0.0001) but correlated with them (P< 0.01). Pleural sIL-6R and albumin levels correlated (P< 0.01), suggesting a transudation of sIL-6R from the serum. Pleural sgp130 levels (10.9 ± 1.0 ng/ml) were lower than serum levels (24.6 ± 2.8 ng/ml; P< 0.002). After gel filtration of pleural fluid, the bulk of IL-6 (>90%) was recovered in a 15 000–30 000 fraction, corresponding to the expected mol. wt of free IL-6. These results suggest a production and a sequestration of IL-6 in the pleural cavity in all studied conditions.     

gp130胞外区近膜端缺失的突变体介导IL-6信号的研究

目的研究ｇｐ１３０胞外区远膜端和近膜端在ＩＬ－６信号转导中的作用。方法用分子克隆手段构建全长的膜结合型ｇｐ１３０分子和胞外区第３０１～５８２位氨基酸残基缺失的突变体分子，并通过阻滞电泳方法比较突变体与野生型分子在传导信号方面的差异。结果通过酶切鉴定、序列分析和表达检测，证明野生型和突变体ｃＤＮＡ表达载体构建正确，并有效表达；阻滞电泳结果表明，在ＳＫＯ－００７细胞和Ｍｏｌｔ－４细胞中，突变体分子与野生型ｇｐ１３０都能介导ＩＬ－６信号。结论ｇｐ１３０分子胞外区远膜端在ＩＬ－６信号转导中发挥重要作用；而近膜端并非ＩＬ－６信号转导所必需。     

抗人gp130单克隆抗体的制备及其生物学特性分析

目的:制备小鼠抗人IL-6Rβ(gp130)单克隆抗体,并分析其生物学特性及初步的免疫学功能。方法:用gp130抗原免疫BALB/c小鼠,经三次免疫获得高效价的ELISA结果后,取小鼠的脾细胞和SP2/0骨髓瘤细胞进行融合,经多次亚克隆筛选得到稳定分泌抗gp130单克隆抗体的杂交瘤细胞株。大量扩增杂交瘤细胞,收集细胞上清,随即过亲合层析柱进行纯化,对经纯化的抗人gp130单克隆抗体进行亚型鉴定,用Western blot及间接ELISA、biacore方法分析抗人gp130单克隆抗体的纯度、特异性及亲和力,用FACS术检测抗人gp130单克隆抗体与膜表面富含IL-6受体的U266细胞系的结合率,同时建立IL-6诱导的U266细胞增殖系统,用以检测和分析抗人gp130单克隆抗体的抑制和阻断效应。结果:本研究获得了多株能够稳定分泌抗人gp130单克隆抗体的细胞株,取其中一株(14C4)进行分析,表明其亚型属于IgG2b,轻链为κ链,经Western blot及间接ELISA证明此株抗体有较高的纯度及特异性,biacore结果显示14C4与抗原结合的亲和力为2.62E-10,FACS结果证实能与U266细胞表面的gp130特异性结合,并且呈剂量依赖性,细胞增殖实验说明14C4在一定程度上可抑制IL-6诱导的U266细胞的增殖。结论:初步成功制备了抗gp130单克隆抗体,并且具备较好的生物学特性,为研究人IL-6gp130在抗感染、炎症以及肿瘤和自身免疫病学中的诊断和治疗中的意义提供了有效的工具和手段。     

High circulating levels of biologically inactive IL-6/SIL-6 receptor complexes in systemic juvenile idiopathic arthritis: evidence for serum factors interfering with the binding to gp130

We previously demonstrated that high levels of IL-6/sIL-6R complexes are present in sera of patients with systemic juvenile idiopathic arthritis (s-JIA) and that the amount of IL-6 estimated in the IL-6/sIL-6R complexes is markedly higher than that measured by the B9 assay. Here, we show that two additional bioassays, employing human myeloma XG-1 cells and human hepatoma Hep3B cells, detected serum IL-6 levels similar to those measured by the B9 assay and approximately 10-fold lower than the IL-6 levels estimated to be present in the IL-6/sIL-6R complex. Using an assay for the measurement of the amount of circulating IL-6 complexed with the sIL-6R and available for binding to gp130 (gp130 binding activity), we show that the IL-6/gp130 binding activity is similar to that detected by the bioassays and again significantly lower than that estimated to be present in the IL-6/sIL-6R complex. Addition of recombinant human IL-6 (rhIL-6) to sera of patients or controls results in a markedly lower increase in the gp130 binding activity in patients than in controls. Moreover, sera from s-JIA patients inhibited in a dose dependent manner the gp130 binding activity assay. These results show that sera from patients with s-JIA contain a factor, or factors, that inhibit(s) the binding of the IL-6/sIL-6R complex to gp130. This inhibitory activity does not appear to be due to soluble gp130, C-reactive protein or autoantibodies to IL-6.     

Endotoxemia enhances expression of the signaling receptor (GP130) on protein and molecular level

Interleukin 6 (IL-6) performs a prominent role during sepsis. To examine the molecular regulation of IL-6, IL-6 receptor, and signaling receptor gp130 during endotoxemia, nine healthy young volunteers received a bolus injection of lipopolysaccharide (LPS) on day 1 and saline on day 2 in a double blind, randomized, placebo-controlled trial. LPS enhanced IL-6 release 300-fold. IL-6 mRNA expression was not significantly altered in blood samples at any time after LPS infusion in vivo, while incubation of whole blood with 50 pg/ml LPS up-regulated IL-6 mRNA levels 8000- to 50,000-fold in vitro. LPS infusion increased synthesis of gp130 mRNA 5.5-fold compared to baseline at 4 h (P < 0.05), while no significant change was observed in the placebo period (P = 0.001 between groups). LPS increased the percentage of gp130 positive neutrophils gp130 700% over baseline at 8 h (P < 0.01 versus baseline and placebo). IL-6 receptor levels were not significantly altered by low-grade endotoxemia. In conclusion, endotoxemia up-regulates gp130 expression in vivo and in vitro. Quantification of IL-6 mRNA expression in circulating leukocytes is unlikely a suitable marker for monitoring of endotoxemia.     

Involvement of gp130/interleukin-6 receptor transducing component in interleukin-11 receptor

The recently cloned interleukin (IL)-11 displays many biological properties in common with those reported for IL-6. In order to analyze the nature and the functionality of the IL-11 receptor we developed a proliferative assay using the human multifactor-dependent cell line TF1. We showed that a blocking monoclonal antibody GPX7 raised against the gp130/IL-6 receptor transducing subunit was also able to inhibit the IL-11-triggered TF1 line proliferation. In addition, involvement of gp130 in IL-11 signaling was demonstrated by an induction of the transducing protein phosphorylation in response to IL-11, as observed for IL-6. In contrast, the blocking monoclonal antibody B-R6, which recognized the gp80/IL-6 binding subunit, failed to interfere with the IL-11 proliferative signal in the TF1 cell line. Similarly, we did not observe any competition between IL-6 and IL-11 for a putative common binding site on the cell surface. These results suggest that the IL-11 binding component is different from the gp80/IL-6 receptor. In conclusion, IL-11, along with IL-6, leukemia inhibitory factor, oncostatin M and ciliary neurotrophic factor, belongs to the same family of cytokines, using gp130 as a transducing protein.     

IL-6 cytokine family and signal transduction: a model of the cytokine system

The interleukin 6 (IL-6) cytokine family, which includes IL-6, leukemia inhibitory factor (LIF), oncostatin M (OSM), ciliary neurotrophic factor (CNTF), IL-11 and cardiotrophin-1 (CT-1), exhibits pleiotropy and redundancy in biological activities. The IL-6 family cytokines exhibit a helical structure. Their receptors belong to the type 1 cytokine receptor family. The receptors of the IL-6 family cytokines share a receptor subunit, which explains one of the mechanisms of functional redundancy. In this review, we describe the general features of the IL-6 cytokine family and its signal transduction mechanisms. Many functional properties of the IL-6 family of cytokines and their receptors are general features of the cytokine system.     

A form of circulating interleukin-6 receptor component soluble gp130 as a potential interleukin-6 inhibitor in inflammatory bowel disease

The presence and the role of soluble gp130, the soluble form of a component of the interleukin (IL)-6 receptor complex, were investigated in inflammatory bowel disease. The serum concentrations of soluble gp130 were increased in ulcerative colitis (active disease, median, 93.5 ng/ml; interquartile range, 26-125 ng/ml; inactive disease, 81 ng/ml, 24.8-137.3 ng/ml) and to a lesser extent in Crohn's disease (active disease, 66 ng/ml, 44.4-87.6 ng/ml; inactive disease, 63 ng/ml, 43.5-82.5 ng/ml) compared to normal controls (43 ng/ml, 27-59 ng/ml). Paired analysis of serum samples showed a decrease of IL-6 and soluble IL-6 receptor concentrations in both diseases and an increase of soluble gp130 concentrations, especially in ulcerative colitis, just after the resolution of disease exacerbation. Size fractionation of the serum revealed that a part of the IL-6 co-eluted with soluble gp130 and soluble IL-6 receptor. The IL-6-induced proliferation of murine B9 hybridoma was enhanced by recombinant soluble IL-6 receptor, whereas the proliferation was inhibited by recombinant soluble gp130. These results indicate that soluble gp130 may function as a natural inhibitor of the IL-6 actions in inflammatory bowel disease.     

Pathological role of IL-6 in the experimental allergic bronchial asthma in mice

Although allergic asthma was described to be associated with the presence of mucosal T-helper (Th)2 cells, it is not entirely clear which factors are responsible for priming of T cells to differentiate into Th2 effector cells in this disease. Interleukin (IL)-6 has been recognized as important because it is secreted by cells of the innate immunity and induces the expansion of the Th2 effector cells, which are major players of the adaptive immune responses. Additionally, IL-6 released by dendritic cells (DCs) inhibits the suppressive function of CD4⁺CD25⁺ T-regulatory cells, thus inhibiting the peripheral tolerance. The signal transduction of IL-6 has recently taught us how this cytokine influences different aspects of the immune response, especially under pathological conditions. IL-6 can bind to the soluble IL-6R, increased after allergen challenge in asthmatic patients, and, through a mechanism called trans-signaling, induces proliferation of cells expressing the cognate receptor gp130. This mechanism appears to be used for proliferation by developed Th2 cells in the airways. In contrast, through the membrane-bound IL-6R, IL-6 controls CD4⁺CD25⁺ survival, as well as the initial stages of the Th2 cells development in the lung. These findings impact the establishment of new therapies for allergic diseases; indeed, blockade of the soluble IL-6R through the fusion protein gp130Fc reduces Th2 cells in the lung, and by blocking the membrane-bound Il-6R, anti-IL-6R antibody treatment induces the number of T-regulatory cells in the lung, thereby reducing the local number of CD4⁺ T-effector cells in experimental asthma.     

JAK-STAT信号通路、IL-1β和IL-6在X射线辐照诱导PC12细胞损伤中的调控作用

目的:探究JAK-STAT信号通路及炎症因子IL-1β、IL-6是否参与X射线诱导的PC12细胞辐射损伤。方法:采用X射线分别以2、4和8 Gy剂量照射PC12细胞,照射后24 h通过酶联免疫法检测IL-1β和IL-6的表达水平;Western blot检测p-JAK1、p-JAK2、p-STAT1、p-STAT3和p-STAT5的蛋白水平。结果:与正常对照组相比,细胞经不同剂量X射线照射24 h后,IL-1β和IL-6的表达水平均升高,且与辐照剂量呈剂量依赖性;p-JAK1、pJAK2、p-STAT1、p-STAT3和p-STAT5的蛋白水平均升高,且上调程度与辐照剂量呈剂量依赖性。结论:JAK-STAT信号通路、IL-1β和IL-6可能参与X射线照射诱导PC12细胞的损伤调控。     

Activation of IL-6 production by UV irradiation of blood mononuclear cells from patients with systemic lupus erythematosus.

Cultured mononuclear cells from patients with systemic lupus erythematosus (SLE), rheumatoid arthritis (RA), and normal donors were assayed for their ability to secrete IL-6 both spontaneously and after exposure to UV light. Mononuclear cells from SLE, RA and atopic control patients produced IL-6 spontaneously, while those from normal donors did not. Spontaneous production of IL-6 occurred in the non-adherent cell population. UV light-induced IL-6 production was confined exclusively to the SLE patients and was present only in the macrophage/monocyte fraction. This stimulation was induced by wavelengths in the UVA, UVB but not the UVC portion of the spectrum. These results suggest that cytokine release may be involved in the exacerbations of SLE provoked by photosensitivity.     

Induction of endogenous retroviral gene product (SU) as an acute-phase protein by IL-6 in murine hepatocytes.

The effect of Lps locus and IL-6 on the production of SU (previously termed gp70), a mouse endogenous retroviral gene product, was studied. Back-cross studies using the progeny between (NZB x C3H/HeJ)F1 and C3H/HeJ mice indicate that the basal level of SU is not associated with the Lps locus on chromosome 4. Lipopolysaccharide (LPS) mitogen response-negative mice did not show the enhancement of serum SU production after LPS injection. Spleen cells from LPS-mitogen response-positive but not from negative mice showed increase of IL-6 synthesis in the presence of LPS. Since IL-6 may be involved in the production of serum SU, we tested the effect of IL-6 in a primary hepatocyte culture system. SU production was clearly enhanced in the presence of recombinant IL-6, indicating that IL-6 induced by LPS can enhance the expression of retroviral genome.     

丹红注射液对急性心肌梗死患者经皮冠状动脉介入治疗后血清IL-6和IL-17水平的影响

目的:探讨丹红注射液对急性心肌梗死(acute myocardial infarction,AMI)患者经皮冠状动脉介入治疗(percutaneous coronary intervention,PCI)后血清IL-6和IL-17水平的影响.方法:选取2014年6月至2016年1月在第四军医大学唐都医院心内科急诊PCI术后的120例ST抬高型心肌梗死(ST-elevation myocardial infarction,STEMI)患者,随机分为对照组和研究组,每组各60例.两组均给予常规治疗,而研究组则在常规治疗基础上给予静脉滴注丹红注射液治疗.观察两组临床症状和体征的改善情况、心电图的恢复情况及不良反应发生情况,评估两组的临床疗效.ELISA测定两组患者治疗前和治疗3,7 d后血清IL-6和IL-17的水平.比较两组治疗前后左室射血分数和心肌梗死面积的变化.随访6个月,观察两组患者主要不良心血管事件(major adverse cardiovascular events,MACE)的发生情况.结果:研究组治疗的总有效率为90.00%,显著高于对照组的76.67%,两组间差异有统计学意义(P<0.05);研究组治疗3,7 d后血清IL-6水平分别为(56.38±10.75)ng/mL,(42.52±8.14)ng/mL,均显著低于对照组的(62.73±12.08)ng/mL,(51.65±9.78)ng/mL,两组间差异有统计学意义(P<0.05);研究组治疗3,7 d后血清IL-17水平分别为(28.73±5.68)ng/mL,(22.54±4.55)ng/mL,均显著低于对照组的(34.39±6.21)ng/mL和(29.82±5.74)ng/mL,两组间差异有统计学意义(P<0.05);研究组治疗后的LVEF为54.72%±5.64%,显著高于对照组的49.38%±4.57%,两组间差异有统计学意义(P<0.05);研究组治疗后的心肌梗死面积为10.64%±4.38%,明显低于对照组的16.74%±5.49%,两组间差异有统计学意义(P<0.05);研究组的MACE发生率为5.00%,显著低于对照组的16.67%,两组间差异有统计学意义(P<0.05).结论:丹红注射液可有效降低PCI术后STEMI患者血清L-6和IL-17的水平,改善患者心功能,缩小心肌梗死面积,降低MACE的发生率,安全有效,值得应用于临床.     

Immunohistochemical analysis of the IL-6 family of cytokines and their receptors in benign, hyperplasic, and malignant human prostate

Interleukin-6 (IL-6) and its receptor have been implicated in prostate cancer progression. Because other members of the IL-6 family such as leukaemia inhibitory factor (LIF) and oncostatin M (OSM) share gp130, the signal transduction subunit of their receptors, interpretation of the data without considering the expression of these cytokines and their specific receptor subunits could be misleading. The immunohistochemical pattern of the IL-6 family and their receptor subunits in normal prostate, benign prostatic hyperplasia (BPH), and prostatic carcinoma (PC) was investigated. In normal prostates, gp130 and OSMRalpha were detected exclusively in the stroma and LIFRbeta was very scarce. While IL-6 was scarcely immunolocalized to the basal cells of the epithelium, OSM was detected in the stroma and LIF in both the epithelium and the stroma. This suggests an autocrine role for this family of cytokines in the stroma of normal prostates. In BPH, gp130 and OSMRalpha were detected both in the epithelium and in the stroma, whereas LIFRbeta was localized only to the epithelium. IL-6 localized preferentially to the epithelium, OSM to the stroma, and LIF to both compartments. Therefore, in addition to the autocrine role in the stroma, IL-6 and OSM may play a paracrine role from the stroma to the epithelium in BPH. In PC, gp130 and OSMRalpha were detected both in the epithelium and in the stroma, increasing with rising Gleason grade, whereas LIFRbeta was localized exclusively to the epithelium of low Gleason grade carcinomas. IL-6, LIF, and OSM localized in all cell types, with immunostaining increasing with Gleason grade. These data suggest an autocrine role for these cytokines in the epithelial cells of PC. The distinct pattern of expression of LIFRbeta exclusively in low Gleason grade carcinomas makes LIFRbeta a candidate for malignancy diagnosis. The role of OSM mainly in high Gleason grade carcinomas makes OSM a putative target for prostate cancer therapy.     

Retinoic acid modulates the in vivo and in vitro growth of IL-6 autocrine human myeloma cell lines via induction of apoptosis

We previously showed that IL-6 is an autocrine growth factor for two human myeloma cell lines, RPMI 8226 and U266. We investigated here the in vitro and in vivo effects of all-trans retinoic acid (RA) on the growth and survival of these two cell lines. RA induced a dramatic dose- and time-dependent inhibition of the proliferation of both cell lines. This inhibition was correlated with a down-modulation of the cell surface expression of the IL-6 binding chain (gp80) and the transducing chain (gp130) of the IL-6 receptor (IL-6R). Long-term culture experiments showed that down-modulation of gp80 expression was complete at days 15 and 30 in the presence of 10^–5 and 10^–7 mol/l of RA, respectively. Gp130 expression was greatly decreased, albeit still detectable, in similar culture conditions. RA-mediated interruption of the IL-6 autocrine loop was associated with a decrease of bcl-2 oncoprotein expression and apoptosis of the myeloma cells which was RA concentration- and time-dependent. The in vivo relevance of the effects of RA was studied on tumours which developed in nude mice inoculated with a subclone of RPMI 8226. Whereas tumours grew in all control mice, 40% of tumours regressed within 20 days in RA-treated mice. Cells from regressing tumours featured characteristics of apoptosis and exhibited low gp80 and gp 130 expression. Our study indicate that long-term RA treatment interferes in vivo and in vitro with IL-6 autocrine growth of myeloma cell lines, leading to apoptosis.     

Inhibition of in vitroimmunoglobulin production by IL-12 in murine chronic graft- vs. -host disease: synergism with IL-18

We investigated the effects of IL-12 on immunoglobulin (Ig) production in vitro in murine chronic graft- vs. -host disease (cGVHD), a lupus-like model of overt B cell activation induced by allogeneic stimulation. Addition of IL-12 to cGVHD splenocytes strongly inhibited total Ig (Igκ), IgM and IgG1 production. Although IL-12 down-regulated IL-4, IL-5, IL-9 and IL-10 production, its inhibitory activity on Ig production could not be ascribed to down-regulation of these cytokines, as addition of saturating doses of IL-4, IL-5 and/or IL-9 did not reverse the inhibitory activity of IL-12. Interestingly, IL-12 was also found to suppress the stimulating effect of IL-4 and IL-5 on Ig synthesis by cGVHD splenocytes. Several lines of evidence indicated that the inhibitory activity exerted by IL-12 on Ig production was mediated by IFN-γ. First, IFN-γ was produced in large amounts upon IL-12 stimulation. Secondly, it displayed a potent inhibitory activity on Ig production. Thirdly, Ig production was also inhibited by IL-18, a recently cloned IFN-γ-inducing cytokine. Finally, the inhibitory activity of IL-12 was blocked by anti-IFN-γ monoclonal antibody. We also investigated whether IL-12 down-regulated Ig production by purified cGVHD B cells. We found that IL-12 had only a marginal inhibitory activity on highly purified B cell populations isolated from cGVHD splenocytes and stimulated with IL-4 and IL-5, and that IL-18 was inactive in this respect. However, when the two cytokines were combined, a striking synergy was unmasked not only for IgG1 inhibition but also for IFN-γ production by these B cell populations. Taken together, our results demonstrate that IL-12 inhibits in vitro Ig production by activated splenocytes through IFN-γ production and that it synergizes with IL-18 on activated B cells to inhibit Ig production, through up-regulation of IFN-γ production by B cells.     

Ciprofloxacin treatment in vivo increases the ex vivo capacity of lipopolysaccharide-stimulated human monocytes to produce IL-1, IL-6 and tumour necrosis factor-alpha.

Because in vitro treatment with quinolones, at pharmacological concentrations, modifies lipopolysaccharide (LPS) induced production of cytokines by monocytes, we studied the effect of orally administered ciprofloxacin (25 mg/kg) on the capacity of peripheral blood monocytes of healthy volunteers to produce tumour necrosis factor-alpha (TNF-alpha), IL-1 activity, IL-1 alpha, IL-1 beta and IL-6 ex vivo in response to endotoxin stimulation. After 7 days of ciprofloxacin, the extracellular and cellular production of TNF-alpha, the cellular production of IL-1 activity, the extracellular and cellular production of IL-1 alpha, and the cellular production of IL-6 increased significantly. Seven days after the end of the treatment, values returned to basal levels or even lower. To our knowledge, this is the first demonstration that ciprofloxacin can modulate in vivo the capacity of human monocytes to react to an inflammatory stimulus such as endotoxin.