Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P05231 (interleukin-6)
 23,907 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Murine interleukin-6 (IL-6), when expressed in Escherichia coli using the pUC9 vector, accumulated as insoluble aggregates or 'inclusion bodies'. After selective urea washing of the inclusion bodies, to remove extraneous proteins, murine IL-6 was solubilized with 8 M guanidine hydrochloride and then rapidly purified to homogeneity by gel-permeation chromatography followed by reversed-phase HPLC. It was demonstrated that complete disulfide bond formation in murine IL-6 occurred during the early urea washing/guanidine hydrochloride extraction steps, so no refolding step was required. When fully reduced murine IL-6 was dissolved in 8 M guanidine hydrochloride and allowed to air-oxidize, complete disulfide bond formation, monitored by analytical reversed-phase HPLC, was shown to occur within 13 h at 6 degrees C. About 25 mg pure protein was obtained from 37 g wet cells. This recombinant murine IL-6 had a specific activity in the hybridoma growth factor assay of 2 x 10(8) U/mg, which is equivalent to that of native murine IL-6. During the purification procedure, a number of variant forms of murine IL-6 were isolated and partially characterized. Two of these forms, T1 and T3, were C-terminal deletants of murine IL-6 lacking about 60 and 20 amino acids from the C-terminus, respectively, while the other form, T2, was an N-terminal deletant lacking 37 amino acids from the N-terminus. None of these variant forms of murine IL-6 bound to the murine IL-6 receptor and, consequently, all were inactive in the hybridoma growth factor assay.
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PMID:Purification and characterization of a recombinant murine interleukin-6. Isolation of N- and C-terminally truncated forms. 149 65

This study investigated the effect of prolonged rupture of the amniotic membranes (PROM) and probable maternal or fetal sepsis without PROM on the newborn preterm airway. Bronchoalveolar lavage fluid (BALF) was obtained from 38 infants in the first day of life and analyzed for number of white cells and concentration of interleukin-6 (IL-6). The volume of lung epithelial lining fluid (ELF) was estimated using the urea dilution technique. Infants with PROM (n = 13) and those with sepsis (n = 8) had higher total numbers of white cells in BALF compared with infants without PROM or sepsis (n = 17) (55 and 44 versus 7 x 10(4) white cells, p less than 0.01). Uncorrected and urea-corrected IL-6 concentrations were also higher in the two groups (18.5 and 30.8 versus 5.0 fmol/ml BALF, p less than 0.01; 157.7 and 444 versus 88.5 fmol/ml ELF, p less than 0.05). There was a significant correlation between BALF white cells and uncorrected IL-6 concentrations (rs = 0.78, p less than 0.0001). Detectable serum C-reactive protein in newborn infants was associated with increased levels of IL-6 in BALF (42.2 versus 11.8 fmol/ml BALF, p less than 0.05). We conclude that PROM is associated with airway inflammation and raised levels of IL-6 in neonatal lung fluid within the first 24 h of life and that this may initiate a systemic stress response.
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PMID:Increased levels of bronchoalveolar lavage fluid interleukin-6 in preterm ventilated infants after prolonged rupture of membranes. 155 2

Phagocytosis is the process where specific cells, phagocytes, ingest foreign material, include it in a cytoplasmatic vacuole, called phagosome, and destroy it. The function of phagocytosis in the immune response has been underevaluated for a very long time. Phagocytosis however, appears to be more and more important in our defense against infection and cancer. The uremic patient presents a well known and increased tendency for infectious disease as well as an increased incidence of cancer. Modern methodology for investigation of phagocytic function consists of: 1. measuring the respiratory burst during phagocytosis; by examining the radio-active CO2 production during the glucose metabolization of phagocytosis. 2. During the chemical reaction of the respiratory burst light is produced. This chemiluminescence can be measured in a Lumetron. In uremia the registration of that chemiluminescence can however be disturbed by the presence of uremic toxins, acting as scavengers of free radicals. 3. Measurement of interleukin-1, interleukin-6 or tumor necrosis factor production during phagocytosis. In the present study, we investigated glucose metabolization and radioactive CO2 production without stimulation and after a challenge with Latex, Zymosan or Staphylococcus Aureus. All tests have been performed on 50 microliter whole blood samples. The following uremic situations have been investigated: 1. Several degrees of increasing renal failure. 2. First weeks of hemodialysis maintenance treatment. 3. Hemodialysis session. 4. Course of hemodialysis maintenance treatment. 5. Continuous ambulatory peritoneal dialysis (CAPD) and renal transplantation. 6. Changes after chemical stimulation by a cephalosporin (cefodizime (R)). The Authors report their detailed results of these investigations and conclude as follows: --uremia is a prototype of acquired immune deficiency. --Contact with bio-incompatible membranes during hemodialysis is disastrous for phagocytosis. --Other toxins than the classical urea or creatinine are apparently responsible for the phagocytic disturbances. --Stimulations of phagocytosis with medication such as the cephalosporin, Cefodizime(R) (Hoechst) is possible.
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PMID:[Phagocyte function in uremic patients]. 192 26

Bronchoalveolar lavage fluid (BALF) from subjects with a variety of interstitial lung diseases (active sarcoidosis, pigeon breeders' disease (PBD), asymptomatic pigeon breeders, patients with idiopathic pulmonary fibrosis) and from control subjects were assayed for interleukin-6 (IL-6) using a novel radioimmunoassay system. IL-6 was detectable in BALF from all groups, with disease groups showing significantly increased IL-6 levels compared with controls (P less than 0.01 in all cases). When these results were standardized, using urea to compensate for dilution effects in the BALF, only the asymptomatic pigeon breeders had significantly higher IL-6 levels than the controls (P less than 0.025), with all other groups showing no difference. When albumin was used for standardization, both the PBD group (P less than 0.001) and the sarcoidosis patients (P less than 0.01) had considerably lower levels of IL-6 than the control subjects. Using either albumin or urea for standardization, the PBD patients had significantly lower levels of IL-6 than do their asymptomatic counterparts (P less than 0.001 in both cases). This is contrasted by the finding of greatly elevated levels of IgG in the BALF of the PBD patients compared with asymptomatics (P less than 0.001). There was, however, no relation between IL-6 and IgG in any patient group, although the PBD patients had the lowest IL-6 and highest IgG as a group. These findings may suggest a mechanism by which asymptomatic subjects remain free from clinical complaints.
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PMID:Measurement of interleukin-6 in bronchoalveolar lavage fluid by radioimmunoassay: differences between patients with interstitial lung disease and control subjects. 198 28

In a group of 111 patients with multiple myeloma (MM) comprising a group of 34 patients examined when the diagnosis was established and a group of 77 patients evaluated in different stages of the disease, the author examined the relationship between the interleukin-6 serum level (IL-6), assessed by the method of enzyme immunoanalysis and selected laboratory indicators of the disease. Elevated IL-6 values were recorded in 38% of the patients. In neither of the groups significant relations were found between IL-6 and calcium, urea, creatinine levels, the amount and type of monoclonal immunoglobulin, lacticode dehydrogenase, beta 2-microglobulin, ferritin, IL-2 and its soluble receptor in serum and the incidence of myeloma plasmocytes in bone marrow. In the second (but not in the first) group a significant relationship was recorded between IL-6 levels and the red cell sedimentation rate, the Hb value, the CRP level and serum albumin and the value of thymidinekinase in serum of patients with a value beyond the normal range. From the investigation ensues that examination of IL-6 serum levels in MM contributes so far mainly to improvement of the diagnosis and expedient classification of this disease in clinical practice.
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PMID:[Serum interleukin-6 in multiple myeloma: I. Relation to selected laboratory indicators of disease]. 748 49

The observed increased susceptibility of patients with fulminant hepatic failure for local and systemic infections has been hypothesized to be due to a failure for the hepatic clearance function and subsequent leaking of endogenous endotoxins into the systemic circulation. However, experimental evidence for such a systemic inflammation during liver failure due to endogenous endotoxemia is lacking. Therefore, we designed a study to clarify whether circulating endotoxins due to liver failure could lead to the development of systemic inflammations. In a rat model for liver failure induced by a two-thirds partial hepatectomy, we evaluated the course of circulating tumor necrosis factor and interleukin-6, changes in blood chemistry and hemodynamics, and histopathological changes in the lungs. Partially hepatectomized animals, but not sham-operated animals, demonstrated cardiac failure, increased levels of creatinin and urea, metabolic acidosis, high plasma levels of tumor necrosis factor and interleukin-6, and an influx of PMNs in the lungs-together indicating the development of a systemic inflammatory response. Continuous infusion of recombinant N-terminal bactericidal/permeability-increasing protein (rBPI23), a well described endotoxin-neutralizing protein, prevented these inflammatory reactions. Ex vivo experiments with rat plasma samples confirmed the presence of circulating endotoxins in partially hepatectomized rats as opposed to those treated with rBPI23. Thus, our results indicate that the early phase of liver failure induces a systemic inflammatory response triggered by circulating endotoxins, which can be prevented by perioperative infusion of rBPI23.
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PMID:Liver failure induces a systemic inflammatory response. Prevention by recombinant N-terminal bactericidal/permeability-increasing protein. 748 5

The equilibrium denaturation of an Escherichia coli-derived recombinant murine interleukin-6 (mIL-6) was studied using fluorescence and circular dichroism spectroscopy. The urea-induced unfolding of mIL-6 at pH 4.0 can be described by a two-state unfolding mechanism based on the superimposibility of the CD and fluorescence unfolding transitions. Assuming a two-state mechanism and a linear dependence of the free energy of unfolding on denaturant concentration, a value of 6.9-9.0 kcal/mol was calculated for the free energy of unfolding in the absence of denaturant [delta GU(H2O)]. However, when GuHCl was used as a denaturant at pH 4.0, a biphasic unfolding transition was observed. This unfolding transition has a distinct midpoint occurring at 2.5 M GuHCl, which is indicative of the formation of stable folding intermediates. Similar intermediate folded species were also observed at pH 7.4 when either urea or GuHCl were used as denaturants. The intermediate folded states of mIL-6 exhibited a tendency to aggregate, as judged by the concentration dependence of their fluorescence characteristics. The fluorescence emission maximum of mIL-6 at pH 7.4 in the presence of 1.5 M GuHCl, for example, was blue-shifted from 343 nm at a protein concentration of 50 micrograms/mL to 336 nm at 500 micrograms/mL. Intermediate formation at pH 4.0, using 10 mM sodium acetate buffer and urea as the denaturant, was facilitated by the addition of 0.4 and 0.8 M salt, where the salt was either NaCl or GuHCl.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Equilibrium denaturation of recombinant murine interleukin-6: effect of pH, denaturants, and salt on formation of folding intermediates. 754 97

Cytokines are widely involved in physiologic as well as immunoinflammatory and fibrosing processes of the lung. The aim of this work was to study, by bronchoalveolar lavage, two groups of human interstitial lung diseases (ILD) with fibrosing propensity (ie, idiopathic pulmonary fibrosis [IPF], n = 10; and coal worker's pneumoconiosis [CWP], n = 15). Patients were compared with nonsmoker control subjects (n = 20). Cellularity, proteins, and phospholipids were determined in the alveolar fluids. In addition, two cytokines (interleukin-6 [IL-6] and interferon-gamma [IFN-gamma]), which are presumed to possess respective antifibrotic and profibrotic activities, were measured in the respiratory tract. Compared with control subjects, IPF and simple CWP showed alveolar hypercellularity (p < 0.05) and relative lymphocytosis (p < 0.05). Both exhibited increased alveolar permeability (ie, increased albumin/urea ratio, p < 0.05), with enhanced IL-6 and decreased IFN-gamma in the alveolar spaces (p < 0.05). On the other hand, IPF displayed an associated polymorphonuclear alveolitis, enhanced alveolar epithelial lining fluid (AELF) volume and low surfactant phospholipid levels (p < 0.05 vs control), whereas simple CWP shared an exclusive lymphocytosis, normal AELF volume, and a surfactant lipid overflow (p < 0.05 vs control). Relationships among all of these parameters were found only between alveolar cellularity, neutrophils and IL-6 levels in the AELF of IPF (respectively, r = 0.85, p = 0.0009, and r = 0.89, p = 0.0006). In summary, common alterations of cellular and cytokine turnover were observed in IPF and simple CWP and may reflect activity of the antifibrotic fight in these diseased lungs. Surfactant phospholipid levels are likely to represent a specific disturbance among IPF and CWP, but no clear relationship with respect to the other parameters could be established for explaining the difference in time course outcome.
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PMID:Interleukin-6, interferon-gamma, and phospholipid levels in the alveolar lining fluid of human lungs. Profiles in coal worker's pneumoconiosis and idiopathic pulmonary fibrosis. 777 11

A mutant species of the 185-residue chain of human interleukin-6 lacking 22-residues at its N-terminus and with a Cys-->Ser substitution at positions 45 and 51 was produced in Escherichia coli. The 163-residue protein des-(A1-S22)-[C45S, C51S]interleukin-6, containing a single disulfide bridge, formed inclusion bodies. Mutant interleukin-6 was solubilized in 6 M guanidine hydrochloride, subjected to oxidative refolding and purified to homogeneity by ammonium sulfate precipitation and hydrophobic chromatography. The purity of the mutant species was established by electrophoresis, isoelectrofocusing and reverse-phase HPLC and its structural identity was checked by N-terminal sequencing of both the intact protein and several of its proteolytic fragments. Electrospray mass spectrometry analysis of mutant interleukin-6 gave a molecular mass of 18,695 +/- 2 Da in excellent agreement with the calculated value. Circular dichroic, fluorescence emission and second-derivative ultraviolet absorption spectra indicated that mutant interleukin-6 maintains the overall secondary and tertiary structure, as well as stability characteristics, of the recombinant wild-type human interleukin-6. The urea-induced unfolding of mutant interleukin-6, monitored by circular dichroic measurements in the far-ultraviolet region, occurs as a highly cooperative process with a midpoint of denaturation at 5.5 M urea. The data of the reversible unfolding of mutant interleukin-6 mediated by urea were used to calculate a value of 20.9 +/- 0.4 kJ.mol-1 for the thermodynamic stability of the protein at 25 degrees C in the absence of denaturant. The biological activity of mutant interleukin-6 was evaluated in vitro by the hybridoma proliferation assay, and in vivo by measuring thrombopoiesis in monkeys. Dose/response effects of the mutant were comparable or even higher than those of the wild-type protein. Overall the results of this study show that mutant interleukin-6 is a biologically active cytokine, which could find practical use as a therapeutic agent.
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PMID:Structure, stability and biological properties of a N-terminally truncated form of recombinant human interleukin-6 containing a single disulfide bond. 785 40

Interleukin-6 (IL-6) is a pleiotropic cytokine that is a regulator of inflammation and immunity. As production of IL-6 may be an important mechanism by which local and systemic inflammatory processes are regulated during lung transplantation, we measured this cytokine concentration in the serum and bronchoalveolar lavage fluid (BALF) collected in 27 lung recipients. IL-6 bioactivity was analyzed using a B cell hybridoma proliferation assay (B9 cell line). Three groups of clinical situations were analyzed: control lung recipients, rejections, and CMV pneumonia. Serum IL-6 concentrations (mean +/- SEM) were 24.2 +/- 3.3 U/ml in the 26 control samples. In 20 allograft rejection episodes, the serum IL-6 concentration was higher than in control samples but the difference was not significant (59.3 +/- 20.5 U/ml, P > 0.05). IL-6 serum levels were significantly increased during the 14 CMV pneumonias (61.2 +/- 11.5 U/ml, P < 0.01). In BALF, IL-6 levels were increased during CMV pneumonia (52.4 +/- 21.9 U/ml BALF), and to a lesser extent during rejection events (14.1 +/- 3.7 U/ml BALF), as compared with controls (5.6 +/- 1.6 U/ml BALF, P < 0.005, and P < 0.05, respectively). Similar results were observed when IL-6/albumin and IL-6/urea ratios were determined so as to compensate for possible dilution effects in BALF. IL-6 in BALF was produced in situ during CMV pneumonia as shown by in situ hybridization experiments that revealed a significant number of IL-6 gene-expressing alveolar cells in this condition. IL-6 concentrations in the serum and in the BALF were compared. There was no correlation between serum and BALF IL-6 concentrations, showing that serum IL-6 levels do not accurately reflect intrapulmonary IL-6 levels do not accurately reflect intrapulmonary IL-6 production. Thus IL-6 is produced within lung transplants during CMV pneumonia, and to a lesser extent during allograft rejection.
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PMID:In situ production of interleukin-6 within human lung allografts displaying rejection or cytomegalovirus pneumonia. 821 59


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