Showing papers by "Charles A. Dinarello published in 1993"

The Role of Interleukin-1 in Disease

Abstract: The interleukin-1 family consists of three structurally related polypeptides. The first two are interleukin-1α and interleukin-1β, each of which has a broad spectrum of both beneficial and harmful biologic actions, and the third is interleukin-1-receptor antagonist, which inhibits the activities of interleukin-1. Among the properties of the two forms of interleukin-1 (α and β) is the ability to induce fever, sleep, anorexia, and hypotension. Interleukin-1 stimulates the release of pituitary hormones, increases the synthesis of collagenases, resulting in the destruction of cartilage, and stimulates the production of prostaglandins, leading to a decrease in the pain threshold. Interleukin-1 has also been . . .

Anticytokine Strategies in the Treatment of the Systemic Inflammatory Response Syndrome

Abstract: The systemic inflammatory response syndrome (SIRS) is an acute illness characterized by generalized activation of the endothelium. The most severe form of the syndrome is found in patients with shock due to gram-negative sepsis. We examined both animal and limited human data for the contribution of cytokines to this syndrome. Cytokines are endogenously produced proteins of small molecular weight and multiple biological effects. The cytokines interleukin 1 (IL-1) and tumor necrosis factor (TNF), as well as interferon-γ and interleukin 8, are discussed. Laboratory investigations suggest that these cytokines play a critical role in SIRS by promoting the biochemical and clinical characteristics of SIRS. The biochemical changes induced by TNF and IL-1 include increased synthesis of nitric oxide, prostaglandins, platelet-activating factor, and endothelial cell adhesion molecules. Specific blockade of TNF using neutralizing antibodies or soluble receptors to TNF in animal models of SIRS reduces mortality and severity of disease. Similar results have been observed blocking IL-1 using soluble IL-1 receptors or IL-1 receptor antagonists. Preliminary clinical studies suggest that blockade may be useful in treating human SIRS. The various strategies for blocking IL-1 and TNF are presented; in addition, their mechanism(s) of action and safety in humans are discussed. We conclude that based on animal studies and preliminary clinical trials, strategies to block IL-1 or TNF may benefit patients with the syndrome, although thorough clinical trials have not been completed. ( JAMA . 1993;269:1829-1835)

Antiinflammatory properties of hepatic acute phase proteins: preferential induction of interleukin 1 (IL-1) receptor antagonist over IL-1 beta synthesis by human peripheral blood mononuclear cells.

Abstract: This study was undertaken to determine whether acute phase proteins (APP) induce the synthesis of interleukin 1 beta (IL-1 beta) and its specific antagonist, IL-1 receptor antagonist (IL-1Ra), in human peripheral blood mononuclear cells (PBMC). PBMC from healthy volunteers were incubated with C-reactive protein (CRP), alpha 1-antitrypsin (alpha 1-AT), or alpha 1-acid glycoprotein (AGP), and the levels of IL-1 beta and IL-1Ra produced were measured by specific radioimmunoassay. To evaluate the effects of alpha 1-AT further, a synthetic pentapeptide FVYLI corresponding to the minimal binding sequence for the serpine-enzyme complex receptor was also evaluated. PBMC incubated for 24 h with CRP, alpha 1-AT, or the pentapeptide FVYLI synthesized large quantities of IL-1Ra, 5-10-fold greater than the amount of IL-1 beta produced by these cells. AGP induced significantly less IL-1Ra than the other APP tested. These effects were shown to be specific, in that polyclonal antibodies against CRP, alpha 1-AT, and AGP eliminated the cytokine production induced by these respective proteins. CRP, alpha 1-AT, FVYLI, and AGP were synergistic with low concentrations of endotoxin in the induction of both IL-1Ra and IL-1 beta synthesis. We suggest that the preferential induction of IL-1Ra by APP may contribute to their antiinflammatory effects and provide an important regulatory signal for the acute phase response.

Intravenous endotoxin suppresses the cytokine response of peripheral blood mononuclear cells of healthy humans.

Abstract: When administered parenterally, endotoxin stimulates the synthesis of IL-1, TNF-alpha, and IL-6. However, this initial injection induces tolerance; a second injection of endotoxin results in lower levels of circulating cytokines. In our study, five healthy male volunteers between the ages of 18 and 30 were injected with Escherichia coli endotoxin. Four subjects received only saline. Immediately before the injection and 3, 6, and 24 h afterward, PBMC were isolated and stimulated in vitro with endotoxin, IL-1, or toxic shock syndrome toxin-1. Inasmuch as CD14+ monocytes are the primary source of the cytokines induced by these stimuli, results are expressed as cytokine production per 10(6) CD14+ cells. Six h after endotoxin injection, endotoxin-stimulated CD14+ cells synthesized 66% less IL-1 beta (p < 0.01), 47% less TNF-alpha (p < 0.001), 56% less IL-6 (p < 0.01), and 49% less IL-8 (p < 0.01) than cells obtained before the injection. This suppression was not specific for endotoxin; IL-1 beta-induced IL-1 alpha and TNF-alpha were reduced by 84% (p = 0.01) and 68% (p < 0.001), respectively. A decrease in cytokine synthesis was also observed using toxic shock syndrome toxin-1 as a stimulus: 57% for IL-1 beta (p = 0.06), 70% for TNF-alpha (p < 0.01), 56% for IL-6 (p < 0.05), and 71% for IL-8 (p = 0.001). When data were expressed as cytokine production per 10(6) PBMC, cells isolated 3 h after endotoxin injection synthesized significantly less stimulus-induced IL-1, TNF-alpha, IL-6, and IL-8 than did PBMC from saline-injected controls. We conclude that endotoxin tolerance is due, in part, to changes in the stimulus-induced cytokine response of circulating CD14+ cells.

Induction of circulating IL-1 receptor antagonist by IFN treatment.

Abstract: This study was undertaken to determine whether IFN induce IL-1 receptor antagonist (IL-1Ra), a specific inhibitor of IL-1. Plasma samples were obtained from healthy volunteers (n = 5) and patients with chronic hepatitis C (n = 5) treated with IFN-alpha, and from patients with renal cell carcinoma (n = 6) treated with IFN-gamma and assayed for IL-1Ra by a specific radioimmunoassay. Both types of IFN were administered subcutaneously. In vitro studies were carried out with PBMC from healthy volunteers. A single, low and nontoxic dose (1 x 10(6) U) of IFN-alpha induced circulating IL-1Ra, which reached peak levels within 12 h. This effect was dose-dependent and more pronounced with a higher dose (5 x 10(6) U). Peak IL-1Ra levels 12 h after 5 x 10(6) U IFN-alpha were 4.16 +/- 0.35 ng/ml in healthy volunteers and 5.7 +/- 0.73 ng/ml in patients with chronic hepatitis C (difference not significant). Thereafter levels declined but remained elevated for 24 h. IFN-gamma treatment led only to a modest increase of circulating IL-1Ra even at a dose of 400 micrograms; this dose, however, was associated with side effects similar to those seen after injection of 5 x 10(6) U IFN-alpha. PBMC stimulated with IFN-alpha or IFN-gamma produced IL-1Ra in vitro. The induction of IL-1Ra may contribute to the antiviral, anti-inflammatory, and antiproliferative effects of IFN.

Measuring circulating cytokines.

Abstract: Cytokines, i.e., regulatory proteins derived primarily (but not exclusively) from cells of the immune system, are receiving increasing attention for their influences on physiological processes. This paper outlines several of the unique characteristics of cytokines and discusses the pitfalls encountered when measuring them in biological fluids. At present, each available assay has a combination of advantages and drawbacks; therefore, investigators must be aware of the trade-offs and choose the assay that best addresses their needs. The factors that affect cytokine measurement also influence cytokine activity in vivo; thus they are important from a physiological as well as methodological standpoint. Moreover, the absolute concentration of a single cytokine is probably less important than the balance between that cytokine and its natural antagonists.

Histamine enhances interleukin (IL)-1-induced IL-1 gene expression and protein synthesis via H2 receptors in peripheral blood mononuclear cells. Comparison with IL-1 receptor antagonist.

Abstract: Histamine and IL-1 have been implicated in the pathogenesis of chronic inflammatory diseases, such as pulmonary allergic reactions and rheumatoid arthritis. We therefore investigated whether histamine modulated the synthesis of IL-1 beta. Human PBMC were stimulated with IL-1 alpha (10 ng/ml) in the absence or presence of histamine (10(-9)-10(-4) M). Histamine alone did not induce protein synthesis or mRNA accumulation for IL-1 beta. IL-1 alpha-induced IL-1 beta synthesis was enhanced two to threefold by histamine concentrations from 10(-6)-10(-4) M. Cimetidine, an H2 receptor antagonist, reversed the histamine (10(-5) M)-mediated increase in IL-1 alpha-induced IL-1 beta synthesis. Diphenhydramine, an H1 receptor antagonist, had no effect. Indomethacin, a cyclooxygenase inhibitor, significantly reduced IL-1 alpha-induced IL-1 beta synthesis, but had no effect on the histamine-mediated increase in IL-1 alpha-induced IL-1 beta synthesis. Histamine (10(-5) M) enhanced and sustained IL-1 beta mRNA levels in IL-1 alpha-stimulated PBMC. However, histamine reduced IL-1 beta mRNA half-life (2.4 vs 1.2 h), suggesting that histamine enhances IL-1 alpha-induced IL-1 beta synthesis at the level of transcriptional activation. On the other hand, histamine (10(-5) M) did not affect IL-1 alpha-induced synthesis of IL-1 receptor antagonist. These results suggest that mast cells may sustain chronic inflammatory processes by upregulating self-induction of IL-1 through histamine release.

Elaboration of interleukin 1-receptor antagonist is not attenuated by glucocorticoids after endotoxemia.

Abstract: • The body's response to infection/inflammation is initiated by the elaboration of cytokines, such as tumor necrosis factor, interleukin 1-β (IL-1-β), IL-6, and IL-8. Cytokines, in turn, stimulate the pituitary-adrenal axis, and it has been suggested that the corticosteroids elaborated serve as negative feedback signals to diminish inflammatory events. To test this hypothesis, we administered hydrocortisone shortly before endotoxin administration to normal volunteers. Steroids greatly reduced the clinical response to endotoxin and attenuated the appearance of tumor necrosis factor, IL-6, and IL-8 in the circulation. In contrast, IL-1–receptor antagonist, a competitive antagonist of the IL-1 receptor, was unaffected by steroid administration. These data suggest that IL-1–receptor antagonist may act in synergism with corticosteroids to reduce inflammation. Elevation of concentrations of these two factors, corticosteroids and IL-1–receptor antagonist, in plasma appears to be the mechanism used by the body to overcome the effects of inflammatory cytokines. ( Arch Surg . 1993;128:138-144)

The interleukin-1 receptor antagonist can either reduce or enhance the lethality of Klebsiella pneumoniae sepsis in newborn rats.

Abstract: Klebsiella pneumoniae, a worldwide cause of nosocomial infections, is one of the most common causes of death in newborns in nurseries. In this study, we investigated the role of interleukin-1 (IL-1) in an experimental animal model of neonatal sepsis, using a natural antagonist of IL-1 receptors, the IL-1 receptor antagonist (IL-1Ra), to block IL-1's effects in neonatal Klebsiella sepsis in the absence of antibiotic treatment. Newborn Wistar-Kyoto rats were injected intraperitoneally with a single dose (10 mg/kg) of either IL-1Ra (n = 43) or human serum albumin as a control (n = 40). At the same time, a 50% lethal dose of K. pneumoniae was injected subcutaneously. No antibiotics were given at any time. After 10 days, survival was 60% for the albumin group and 80% for the IL-1Ra group (P < 0.01). IL-1Ra treatment also afforded protection when the dose of bacteria was increased sixfold (P < 0.01). There were two episodes of leukopenia in the control group, which were suppressed by IL-1Ra (P < 0.01 and P < 0.001). IL-1 and IL-6 levels were lower in the IL-1Ra-treated group (P < 0.05 and P < 0.001, respectively). No differences between the two groups were observed in the number of bacteria in cultures of the blood, lungs, liver, or spleen. When IL-1Ra (10 mg/kg) was given both at time zero and 24 h after bacterial challenge, lethality was significantly increased (P < 0.01). Single doses of IL-1Ra of from 20 to 40 mg/kg progressively increased lethality compared with controls (P < 0.01) in both Wistar-Kyoto and Sprague-Dawley strain rats. In the same model, low doses of IL-1 itself (0.4 ng per rat), given 24 h prior to bacterial challenge, afforded protection (P < 0.001). These studies suggest that, in the absence of antibiotics, partial blockade of IL-1 receptors improves survival, whereas a longer or greater blockade increases lethality in newborn rats infected with K. pneumoniae.

Expression of interleukin-1 receptor antagonist (IL-1ra) by human circulating polymorphonuclear cells

Abstract: After appropriate stimulation, mononuclear phagocytes express a specific inhibitor of interleukin (IL)-1, now re-named IL-1 receptor antagonist (IL-1ra). In this study we have examined the production of IL-1ra by polymorphonuclear cells (PMN). Human PMN isolated from peripheral blood expressed low but detectable levels of IL-1ra transcripts, which were considerably augmented after treatment with lipopolysaccharides (LPS) and cytokines [IL-4, granulocyte (G)- and granulocyte macrophage (GM)-Colony Stimulating factor (CSF), and tumor necrosis factor (TNF)]. The levels of induced IL-1 ra transcripts were comparable to those observed in endotoxin-stimulated human monocytes. By contrast IL-1 beta, interferon (IFN)-gamma and chemotactic factors (fMLP, C5a and IL-8) failed to promote IL-1ra expression in PMN. IL-1ra induction by LPS reached peak levels at 10 ng/ml after 3-6 h and remained sustained 24 h after stimulation. Induction by LPS and GM-CSF appears to be at the transcriptional level, as assessed by inhibiting mRNA synthesis with actinomycin D. Inhibition of protein synthesis by cycloheximide superinduced both basal and inducible IL-1ra mRNA. In addition to expressing mRNA, PMN also produce IL-1ra protein. Secretion of IL-1ra was induced in PMN treated with LPS, IL-4 and GM-CSF, but not by IL-1 beta, IFN-gamma and fMLP, thus yielding results that paralleled those seen in Northern blot experiments. These data indicate that, among myelomonocytic cells, PMN, in addition to mononuclear phagocytes, can express IL-1ra, suggesting that PMN, while exerting a series of pro-inflammatory activities, may also modulate the inflammatory potential of IL-1 in tissues.

Interleukin-1 (IL-1) receptor antagonist prevents Staphylococcus epidermidis-induced hypotension and reduces circulating levels of tumor necrosis factor and IL-1 beta in rabbits.

Abstract: Similar to shock in gram-negative sepsis, shock from gram-positive organisms is mediated, in part, by tumor necrosis factor (TNF) and interleukin-1 (IL-1). In the present study, rabbits were infused with IL-1 receptor antagonist (IL-1ra) prior to and during Staphylococcus epidermidis-induced hypotension. After injection of bacteria, a maximal fall in mean arterial pressure to -42% below baseline occurred at 200 min in vehicle-treated animals compared with a nonsignificant decrease of only 7% in the IL-1ra-treated group (P

Identification of the Promoter Region of Human Interleukin 1 Type I Receptor Gene: Multiple Initiation Sites, High G + C Content, and Constitutive Expression

Abstract: To better understand the role of interleukin 1 (IL-1) and its receptor in disease, we have isolated a genomic clone of the human IL-1 type I receptor and have identified the promoter region There are multiple transcriptional initiation sites as demonstrated by primer extension DNA sequence analysis shows that the promoter region contains neither a TATA nor a CAAT box; however, the 5' upstream regulatory elements contain two AP-1-like binding sites The internal regulatory sequences found immediately downstream to the 5' transcriptional start site contain four Sp1 binding domains and have a high G+C content of 75% This portion of the 5' untranslated region of the mRNA can form stable secondary structure as predicted by computer modeling Base pairs -4 to + 10 share striking resemblance to an initiator sequence that directs basal expression of certain TATA-less genes-eg, terminal deoxynucleotidyltransferase in lymphocytes The IL-1 receptor promoter directs basal expression of chloramphenicol acetyltransferase in transiently transfected cells Overall, the promoter of the IL-1 type I receptor gene resembles that of constitutively expressed genes that have housekeeping- and/or growth-related functions The constitutive nature of the promoter may account for this gene being expressed at low levels in diverse cell types Our finding sheds more understanding into the mechanisms governing the regulation of the IL-1 receptor in health and disease

Cytokine Measurements in Septic Shock

Abstract: The cytokines interleukin-1 (IL-1) and tumor necrosis factor (TNF) affect nearly every cell type by increasing the production of substances that promote local and systemic inflammatory processes. These include the up-regulation of the genes for cyclooxygenase and nitric oxide synthases, the release of platelet-activating factor, and the synthesis of endothelial adhesion molecules. Vasodilation, reduced tissue oxidation, and leukocyte-mediated necrosis are thought to contribute to organ failure and death in patients with septic shock. Although IL-1 and TNF are capable of inducing shock individually, of greater biological relevance is the synergistic action of these two cytokines. In animal models of disease, the roles of IL-1 and TNF have been defined by specifically inhibiting each cytokine. The anticytokine strategies for treatment of septic shock follow the same approach. Interleukin-1 can be blocked by reducing its synthesis [1]; infusing IL-1-receptor antagonist [2-4]; or administering soluble (extracellular) IL-1 receptors [5]. Blocking TNF can be accomplished by reducing its synthesis, infusing neutralizing antibodies, or administering TNF-binding proteins that are the soluble forms of p55 or p75 TNF receptors [6, 7]. These agents are now being assessed in clinical trials. What triggers the synthesis and release of IL-1 and TNF? The most potent agonist is bacterial lipopolysaccharide (or endotoxin), although it is important to remember that exotoxins from gram-positive bacteria and some fungal products can also stimulate IL-1 and TNF synthesis. Human blood monocytes are exquisitely sensitive to endotoxin, producing IL-1 and TNF in vitro in response to 25 to 50 pg/mL of endotoxin, a concentration achieved in the circulation during septic shock as reported by Casey and colleagues [8] in this issue of Annals. Human volunteers receiving an injection of 3 ng/kg of Escherichia coli-derived lipopolysaccharide show a dramatic increase in circulating TNF- (from <5 pg/mL to as much as 750 pg/mL, depending on the assay method). The theoretical maximum concentration of lipopolysaccharide in the blood of these volunteers would be approximately 25 pg/mL. Thus, it is of interest in understanding the pathogenesis of septic shock that Casey and colleagues report that circulating levels of IL-1 , TNF-, and IL-6 correlate with mortality in these patients. Moreover, when the data were analyzed by a lipopolysaccharide-cytokine score, which is based on lipopolysaccharide and cytokine concentrations, the correlation with mortality was highly significant. In the analysis of these patients, IL-6 was the cytokine that was most consistently elevated and that correlated best with mortality, as other studies have shown [9]. However, because IL-6 lacks the ability to induce a shock-like syndrome in animals or humans, the plasma IL-6 level is a marker rather than a cause of the syndrome. Interleukin-6 production appears to reflect biologically active IL-1 and TNF, in that blocking either of these latter cytokines significantly reduces the IL-6 level [10-12]. The importance of IL-1 or TNF, or both, in the pathogenesis of septic shock in patients must be proved by intervention studies showing improved survival when these cytokines are specifically blocked. Clearly, correlative clinical studies of plasma cytokine levels and mortality do not establish causality. Thus, the study by Casey and colleagues deserves a careful reading for other reasons. In a recent clinical trial of an anti-TNF monoclonal antibody for septic shock, increased survival was seen only in patients with the highest levels of circulating TNF- [9]. In a phase III trial of IL-1- receptor antagonist, a statistically significant improvement in survival was observed only in patients with sepsis who were at the highest risk for death [13]. Although the levels of circulating IL-1 are unknown in that study, we speculate that those patients with the highest risk for death would have shown the highest levels of IL-1 if it was collected and measured by validated methods [8, 14, 15]. Therefore, the value of measuring IL-1 and TNF- in the circulation may be to identify which patients are likely to benefit from anticytokine therapy. This information has the potential to improve the design of clinical trials and thus reduce the possibility that a useful therapy for septic shock will be disregarded because of apparent failure of the trial through misapplication of the therapy. Once a new therapy is approved, information on cytokine status can also reduce costs by identifying the appropriate patients for treatment. Although these are theoretical prospects, several pitfalls need to be overcome. First, plasma contains factors that interfere with cytokine assays (reviewed in [16]); these include nonspecific and specific binding proteins. Casey and colleagues carefully tested their assays to be sure that physiologically relevant amounts of the cytokines could be recovered. They checked samples with high immunoreactivity by diluting and retesting them, and they verified immunoassay results by bioassay. They also rapidly separated the plasma from the blood cells and thus avoided artifacts associated with clotted blood. The clinical study of cytokines is in disarray because of the proliferation of commercial assay kits that are poorly characterized by the manufacturers and are used indiscriminately by researchers. Casey and colleagues are to be commended for their careful attention to assay validation. A Danish group has recently validated an IL-1 enzyme-linked immunosorbent assay (ELISA) by column chromatography and bioassay procedures and showed a correlation between plasma IL-1 levels and mortality in patients with severe burn injury [15]. Second, validated assay systems can still yield different results. Although Casey and colleagues found that high circulating IL-1 levels were associated with high mortality, others have found contrasting results using different assay methods. Which method is correct? It is possible that each assay correctly answers different questions. Bioassays obviously measure biologically active forms of IL-1. These include mature 17-kd IL-1 and smaller fragments, regardless of whether IL-1 is free or bound to carrier proteins such as 2-macroglobulin. The radioimmunoassay used in some studies [17, 18] detects the relatively inactive 31-kd pro-IL-1 as well as bound and free forms of mature and fragmented IL-1 [14]. The IL-1 ELISA of Cistron that was used in Casey and colleagues' study detects about 10% to 15% pro-IL-1 [19] and does not detect IL-1 fragments nor IL-1 bound to carrier proteins. (Information provided on request from Richard Dondero of Cistron Biotechnologies. Clearly, such information is critical to the interpretation of assay results. Investigators pay a premium price for these assay kits and they have a right to demand that the kits are well characterized. All reputable kit manufacturers should furnish such information and data.) The bioassay and radioimmunoassay are better suited to determine if a host is producing IL-1 at all. It is important to remember that picomolar concentrations of IL-1 enhance host defense mechanisms [20] and that only excessive amounts promote disease. Free circulating IL-1 may exist only after natural binding proteins are diminished by disease or become saturated by excess IL-1 production resulting in a pathological state. Third, septic shock does not provide the clinician with the luxury of waiting several hours for the results of a cytokine assay before making a decision about treatment. We do not recommend routine cytokine assays for clinical decision making in septic shock. Interleukin-1 and TNF contribute to septic shock by increasing the expression of genes coding for the synthesis of small mediator molecules such as prostaglandins and nitric oxide. This increased expression can result in a 4- to 6-hour difference between peak cytokine levels in the circulation and the onset of clinical shock. We do recommend prospective studies designed to show a constellation of early clinical assessments that correlates with circulating cytokine levels and, at the same time, the risk for death in these patients. It is possible to determine in less than 4 hours the amount of IL-1 , TNF, and IL-6 messenger RNA in a small volume of blood using the polymerase chain reaction. If this method and cytokine assays can be applied to prospective trials, the design of anticytokine therapy trials and treatment of patients with septic shock could be improved. Studies in animals clearly show the disadvantage of late anticytokine treatment, and humans entered late into anticytokine intervention are probably also at a disadvantage.

Detection of Tumor Necrosis Factor Soluble Receptor p55 in Blood Samples from Healthy and Endotoxemic Humans

Abstract: The tumor necrosis factor (TNF) soluble receptor derived from the cell surface p55 TNF receptor (TNFsRp55) is a naturally occurring substance generated during infection and inflammation. TNFsRp55 inhibits biologic effects of TNF. An RIA was developed to quantitate TNFsRp55 in human blood. Recovery of TNFsRp55 from blood anticoagulated with EDTA was optimal compared with recovery from serum or heparinized plasma. TNF did not interfere with the assay. With the RIA based on radiolabeled nonglycosylated Escherichia coli-derived recombinant TNFsRp55, a mean concentration of 198 +/- 15 pg/mL was found in 14 volunteers. When glycosylated CHO cell-derived TNFsRp55 was used, the mean level was 1656 +/- 95 pg/mL. Infusion of endotoxin into volunteers induced TNFsRp55, which peaked at 517 +/- 99 pg/mL for the E. coli-based RIA and 7300 +/- 1810 pg/mL for the CHO cell-based RIA. These findings demonstrate that blood collected in EDTA is optimal for measuring circulating TNFsRp55 and that this soluble receptor is present in health but elevated during endotoxemia.

Ciliary neurotrophic factor is an endogenous pyrogen.

Abstract: Fever is initiated by the action of polypeptide cytokines called endogenous pyrogens, which are produced by the host during inflammation, trauma, or infection and which elevate the thermoregulatory set point in the hypothalamus. Ciliary neurotrophic factor (CNTF) supports the differentiation and survival of central and peripheral neurons. We describe the activity of CNTF as intrinsically pyrogenic in the rabbit. CNTF induced a monophasic fever which rose rapidly (within the first 12 min) following intravenous injection; CNTF fever was blocked by pretreatment with indomethacin. The fever induced by CNTF was not due to contaminating endotoxins. Increasing doses of CNTF resulted in prolongation of the fever, suggesting the subsequent induction of additional endogenous pyrogenic activity. After passive transfer of plasma obtained during CNTF-induced fever, endogenous pyrogen activity was not present in the circulation; CNTF also did not induce the endogenous pyrogens interleukin 1, tumor necrosis factor, or interleukin 6 in vitro. Nevertheless, a second endogenous pyrogen may originate within the central nervous system following the systemic injection of CNTF. Of the four endogenous pyrogens described to date (interleukin 1, tumor necrosis factor, interferon, and interleukin 6), CNTF, like interleukin 6, utilizes the cell-surface gp 130 signal-transduction apparatus.

Differential interleukin-1 receptor antagonism on pancreatic beta and alpha cells. Studies in rodent and human islets and in normal rats.

Abstract: The monokines interleukin-1α and -β have been implicated as effector molecules in the immune-mediated pancreatic beta-cell destruction leading to insulin-dependent diabetes mellitus. Here we investigated the effects of interleukin-1 receptor antagonism on insulin and glucagon release of rat, mouse and human islets exposed to recombinant human interleukin-1β, and on interleukin-1β induced changes in blood glucose, serum insulin and serum glucagon levels in Wistar Kyoto rats. The interleukin-1 receptor antagonist reduced the co-mitogenic effect of interleukin-1β on mouse and rat thymocytes with a 50% inhibitory concentration of 10- and 100-fold molar excess, respectively. Complete inhibition was obtained with a 100–1,000-fold molar excess. However, at a 100-fold molar excess the interleukin-1 receptor antagonist did not antagonise the potentiating effect of interleukin-1βon rat islet insulin accumulation during 3 and 6 h of exposure or of interleukin-1β-induced inhibition of insulin release after 24 h. In contrast, interleukin-1β-stimulated islet glucagon release was completely antagonised by a 100-fold molar excess of interleukin-1 receptor antagonist. A 10,000-fold molar excess of interleukin-1 receptor antagonist was needed to antagonise interleukin-1β stimulatory and inhibitory effects on rat beta-cell function in vitro. A 100-fold excess of interleukin-1 receptor antagonist could not counteract interleukin-1β effects on mouse and human beta cells, excluding species difference in the efficacy of the human interleukin-1 receptor antagonist. An anti-mouse interleukin-1 receptor type I antibody completely abolished interleukin-1β effects on isolated mouse islets. A 10–100-fold molar excess of interleukin-1 receptor antagonist antagonised interleukin-1β-induced fever, hypercorticosteronaemia and hyperglucagonaemia, but not interleukin-1β-induced reduction in insulin/glucose ratio in normal rats. In conclusion, our results suggest that antagonism of interleukin-1β effects on beta cells requires higher concentrations of interleukin-1 receptor antagonist than those necessary to block interleukin-1 action on islet alpha cells and other interleukin-1 targets in vitro and in vivo. This may contribute to the understanding of the specificity of the immunological beta-cell destruction leading to insulin-dependent diabetes.

Induction of circulating and erythrocyte-bound IL-8 by IL-2 immunotherapy and suppression of its in vitro production by IL-1 receptor antagonist and soluble tumor necrosis factor receptor (p75) chimera.

Abstract: The objective of this study was 1) to investigate the in vivo production of IL-8 in patients undergoing IL-2 immunotherapy and 2) to study the influence of IL-1Ra, soluble TNF receptor p75 (TNFsRp75), and a TNFsRp75-Fc fusion protein on IL-2-induced IL-8 production in vitro. Circulating IL-8 was assessed both in plasma and erythrocyte lysates prepared from patients undergoing IL-2 immunotherapy. IL-8 was detectable in the plasma within 2-4 h after the first IL-2 infusion, reached a peak level after 4 h, and declined rapidly to undetectable within 8 h. Erythrocyte-bound IL-8 was also detected within 4 h of the first IL-2 dose, but levels were higher than those measured in plasma and remained elevated long after the plasma levels had become undetectable. On day 4 of therapy, the increases in both plasma and the erythrocyte-lysate IL-8 levels induced by an IL-2 injection were less pronounced than on day 1. Although IL-1Ra and TNFsRp75-Fc individually had only a modest suppressive effect on IL-2-induced IL-8 production by PBMC in vitro, the combination of IL-1Ra and TNFsRp75-Fc markedly down-regulated IL-2-induced IL-8 synthesis and steady-state mRNA levels. TNFsRp75 had no effect on IL-2-induced IL-8 synthesis. Our studies suggest that the transient detection of IL-8 in plasma early in the course of IL-2 treatment is due to erythrocyte sequestration and that suppressed synthesis, due in part to high levels of circulating IL-1 and TNF antagonists, may play a role later in the course of treatment.

Blocking interleukin-1 in disease.

Abstract: Numerous studies implicate a role for cytokines in the pathogenesis of disease These are primarily derived from experiments in which cytokines are injected into experimental animals and disease activity is monitored Other studies measure elevated cytokines in either animals or humans during the development of disease Although cytokines are thought to play a role in the outcome of various diseases, only a few have been directly implicated as mediators of the pathogenic mechanisms of illness and death of the host Recent studies using specific cytokine antagonism have shed considerable light on which cytokines appear to be playing a critical role

Bacterial lipopolysaccharide induction of IL-6 in rat telencephalic cells is mediated in part by IL-1.

Abstract: Interleukin-6 (IL-6) appears in the cerebrospinal fluid (CSF) of patients with acute infection of the central nervous system, and in the brains and CSF of experimental animals following systemic or intracerebral injection of bacterial endotoxin (Escherichia coli lipopolysaccharide, LPS). Since LPS is known to induce secretion of interleukin-1 (IL-1) in many cell types including those of the brain, and IL-1 can induce IL-6 in brain tissue it appeared reasonable to postulate that the effects of LPS on IL-6 production were mediated through IL-1 induction. To test this hypothesis, the effects of IL-1 receptor antagonist (IL-1Ra) on LPS and IL-1-induced IL-6 secretion were tested in a mixed brain cell culture from 17-day fetal rat, after 12-14 days in culture. IL-6 secretion was induced by IL-1 beta in a concentration as low as 1 x 10(-10) M (p = 0.0008); addition of IL-1Ra was shown to inhibit IL-1-induced changes by 87% (p = 0.0012) at a molar ratio of 100:1, and by 100% at a molar ratio of 1,000:1, LPS stimulated IL-6 secretion progressively over the concentration of 1-100 ng/ml (p = 0.0001). LPS 10 ng/ml-induced IL-6 secretion was inhibited by 66% by IL-1Ra in a concentration of 1,000 ng/ml (p = 0.0077). The inhibitory effect of IL-1Ra was not significantly greater even when used at a concentration of 5,000 ng/ml.(ABSTRACT TRUNCATED AT 250 WORDS)

Antibodies to IL-1β

Abstract: The subject invention concerns a nucleic acid comprising a nucleotide sequence encoding human interleukin-1 (IL-1), and fragments thereof, and the polypeptides and peptides obtained. Specifically, the subject invention comprises the cloning of a cDNA synthesized by reverse transcription of poly(A)RNA isolated from adherent human monocytes stimulated with bacterial endotoxin. The subject invention further concerns antibodies that are immunoreactive with human IL-1β proteins. Human IL-1 is useful to induce the production of IL-2 by activated T-cells; it also acts on B-cells and NK-cells.