Interleukin-1 but not tumour necrosis factor alpha synergistically upregulates the granulocyte-macrophage colony-stimulating factor-induced B7-1 expression of murine Langerhans cells

Epidermal Langerhans cells (LC) express several co-stimulatory molecules such as B7/BB1, which has been implicated as one of the important determinants for potent antigen-presenting function of LC. Recent studies have shown that B7/BB1 antigens comprise three distinct molecules termed B7-1, B7-2 and B7-3. Previous studies have revealed that the phenotypic and functional properties of murine LC are enormously affected by various cytokines including granulocyte-macrophage colony stimulating factor (GM-CSF), interleukin-1 (IL-1), and tumour necrosis factor alpha (TNF-alpha) derived from surrounding keratinocytes. We have already demonstrated that the expression of B7-1 of murine LC is significantly enhanced by GM-CSF, IL-1 or TNF-alpha. In this paper, we present that IL-1, but not TNF-alpha, synergistically up-regulates the GM-CSF-induced B7-1 expression of murine LC.

D-mannose dimer introduced human recombinant interleukin- 1 alpha, NEO IL-1 alpha, exhibits altered tissue distribution in mice

Previous studies have demonstrated that the carbohydrate-introduced recombinant human IL-l alpha exhibited impairment in both biologic activities in all the experiments in vitro and receptor binding capacity compared with intact IL-l alpha. However, the glycosylated IL-l alpha exhibited selective activities in vivo. In this study, we compared the tissue distribution of IL-l alpha and IL-l alpha coupled with D-Mana (l-6)Man [Man2 alpha) (l-6)IL-l alpha] in mice. Mice were injected by intravenous and intraperitoneal routes with 2.0 mu g radiolabeled IL-l alpha. At 1 and 2 h after IP injection, the level of Man2 alpha) (l-6)IL-l alpha decreased twofold compared with that of IL-l alpha in kidney. In contrast, at 1 hour after administration, Man2 alpha) (l-6)IL-l alpha exhibited higher levels than IL-l alpha in blood, heart, and liver. No significant difference was observed in brain at each time point. IV injection demonstrated that Man2 alpha)(l-6)IL-l alpha decreased to approximately one-half the level of rhIL-l alpha in kidney. In contrast, Man(2 alpha) (l-6)IL-l alpha increased twofold over that of IL-l alpha in liver at 1 h after dosing. These findings are consistent with the result of IP injection. There was no significant difference between IL-l alpha and glycosylated IL-l alpha at 4 h after IV administration. These differences in tissue distribution may contribute to the selective activities of glycosylated IL-l alpha in vivo. The results also suggest that by coupling with mannose dimer, it is possible to develop neocytokines prone to liver distribution.

Induction of interleukin 1 receptor antagonist after interleukin 1 therapy in patients with cancer

The interleukin 1 receptor antagonist (IL-1ra) is a naturally occurring molecule that shares homology with IL-1alpha and IL-1beta and binds competitively to IL-1 receptors. Serum concentrations of IL-1ra were measured by ELISA in patients enrolled in Phase I clinical trials of IL-1alpha and IL-1beta given by 15-min infusion. Pretreatment levels of IL-1ra were <1500 (mean, 453 +/- 57) pg/ml. IL-1ra levels were increased in some patients within 1 h of completing the IL-1 infusion. By 2 h after infusion, serum levels of IL-1ra had increased dramatically, and they remained stable 4 h after infusion. There was evidence that peak IL-1ra levels were IL-1 dose dependent. Seven patients treated with IL-1alpha had IL-1ra levels that exceeded 1 microgram/ml. In contrast, serum levels of IL-1 declined rapidly and were undetectable 1 h after completing IL-1 infusion in most patients receiving <1.0 microgram/kg. IL-1ra levels remained slightly elevated over pretreatment values in serum obtained 18-24 h after IL-1 infusion, but there was no evidence for progressive accumulation over repeated days of therapy. A similar pattern of IL-1ra elevation was observed after the last IL-1 infusion on day 6. This study shows that cancer patients produce 2 to >6 log incremental increases in IL-1ra rapidly following treatment with IL-1, a response that has implications for the design of future clinical trials with IL-1 and with agents thought to induce IL-1 production.

Anti-inflammatory and analgesic activities of 3-imino-1-oxoisoindolines in CF1 mice

A series of 3-imino-1-oxoisoindolines were shown to be potent anti-inflammatory and analgesic agents at 8 mg/kg, intraperitoneally in mice. The compounds were also able to protect against lipopolysaccharide induced endotoxic shock and death better than the current clinical agents. These agents appear to function by blocking the release of TNF alpha and IL-1 from macrophages as well as competition with their respective high affinity receptors on target tissue, eg. fibroblasts, and macrophages. In addition lysosomal hydrolytic enzymes were inhibited as well as leukotriene synthesis in macrophages by the agents.

Selective transport of blood-borne interleukin-1 alpha into the posterior division of the septum of the mouse brain

Film autoradiography was used to demonstrate the transport and sites of accumulation of blood-borne radioiodinated interleukin-1 alpha (II-1 alpha) and other cytokines into the brain after intravenous administration. [125 I]Il-1 alpha, [125I]Il-1 beta, [125I]interleukin-1 receptor antagonist (II-1ra), and [125I]tumor necrosis factor-alpha (TNF alpha) labeled the choroid plexus and the capillary network 30 min after injection into the blood, suggesting that these areas may serve as sites of blood-to-brain transport. [125I]Il-1alpha, but not [125I]Il-1beta, [125I]Il-1ra, [125I]TNF alpha, or [125I]interleukin-2 (Il-2), was also found localized to the caudal region of the septal nuclei. Only unlabeled II-1 alpha was able to inhibit this accumulation. These findings provide further evidence for the passage of select cytokines across the blood-brain barrier (BBB) and are the first to identify a target site within the central nervous system (CNS) for a transported cytokine.

Specific targeting of infectious foci with radioiodinated human recombinant interleukin-1 in an experimental model

In the present study, radioiodinated human recombinant interleukin-1 (IL-1) was investigated for its potential to image infectious foci in vivo in an animal model of infection. Twenty-four hours after induction of a Staphylococcus aureus abscess in the left calf muscle, mice were i.v. injected with both iodine-125 labelled IL-1 and iodine-131 labelled myoglobin, a size-matched control agent. The animals were killed for tissue biodistribution studies at 2, 6, 12, 24 and 48 h p.i. Gamma camera images were obtained at 6, 24 and 48 h after injecting mice with 123I-IL-1. Radioiodinated IL-1 rapidly cleared from the body; after 12 h the abscess was the organ with the highest activity. The absolute abscess uptake of 125I-IL-1 remained high compared to 131I-myoglobin, resulting in significantly higher abscess-to-muscle ratios of 125I-IL-1 compared to 131I-myoglobin. The ratios of 125I-IL-1 reached the ultimate value of 44.4+/-10.8 at 48 h p.i., whereas the ratios of 131I-myoglobin did not exceed 5.9+/-0.7. Gamma camera imaging revealed clearly visible abscesses. In conclusion, our results demonstrate specific retention of radioiodinated IL-1 in the abscess, presumably by interaction of IL-1 with its receptor on the inflammatory cells. The high target-to-background ratios that were obtained over the course of time indicate that the IL-1 receptor may be a valuable target for the imaging of infectious foci.

Permeability of the blood-brain barrier to soluble cytokine receptors

Soluble receptors for cytokines can be important regulators of cytokine function. By binding to their cytokine ligands, they act as antagonists and carrier proteins. We investigated whether the blood-to-brain saturable transport of human tumor necrosis factor-alpha (TNF) and human interleukin-1 alpha (IL-1) radioactively labeled with 125I could be blocked by preincubation with their soluble receptors. At ratios of 100:1 and 1,000:1 of receptor to cytokine, the soluble p75 human receptor to TNF (rhuTNFR:Fc) totally blocked the entry of human or murine TNF into the brain. However, the soluble murine receptor to IL-1 (muIL-1R) only partially blocked IL-1 entry. Radioactively labeled rhuTNFR:Fc and muIL-1R were not transported across the blood-brain barrier (BBB) and were no more able to penetrate the BBB than the vascular marker serum albumin. This indicates that the transporter at the BBB for IL-1, but not the one for TNF, can strip the cytokine from its soluble receptor. These findings might be useful in determining which, if any, of the actions exerted on the brain by blood-borne cytokines are due to penetration of the BBB.

Possible role of cytokines in cellular proliferation of the skin transplanted onto nude mice

BACKGROUND AND DESIGN

In recent studies on the behavior of aged skin transplanted onto nude mice, the epidermis of aged and young skin showed an increase in proliferation and thickness following engraftment, and became almost identical. The aim of this study was to ascertain a possible role for the release of local cytokines in this phenomenon. Grafted human skin was injected intradermally with anti-interleukin-6 (IL) and anti-IL-1 alpha, and comparisons of epidermal thymidine incorporation and thickness were made. Grafts injected with irrelevant antibodies served as control.

RESULTS

Interleukin-6 and IL-1 alpha expression were studied in grafts by immunoperoxidase staining. Only IL-6 expression was found in the 1-month grafts. Intradermal injections of anti-IL-1 alpha and anti-IL-6 showed an inhibitory effect on cellular proliferation in the epidermis. A significant difference in the response of epidermal proliferation and, consequently, in thickness was found in samples injected with anti-IL-1 alpha and anti-IL-6 compared with those injected with irrelevant antibodies.

CONCLUSIONS

These data may indicate that local cytokines released by the keratinocytes are involved in the cellular proliferative activity in skin engrafted onto the mice.

Blood-borne interleukin-1 alpha is transported across the endothelial blood-spinal cord barrier of mice

1. Previous work has shown that one mechanism by which blood-borne interleukin-1 alpha (IL-1) may be able to affect the central nervous system (CNS) is by direct transport into the brain across the blood-brain barrier (BBB). The BBB of the brain consists of endothelial (between blood and interstitial fluid) and ependymal (between blood and cerebrospinal fluid) barriers. Which of these barriers IL-1 can cross has not previously been investigated. At the spinal cord, which could be the site of action for some of the effects of IL-1 such as analgesia, the BBB consists only of the endothelial barrier. 2. We show here that IL-1 labelled with 125I (I-IL) is transported across the BBB of the spinal cord by a saturable system similar to the one previously described for the brain. High performance liquid chromatography (HPLC) showed that most of the material entering the spinal cord represented intact I-IL. The BBB of the spinal cord was no more leaky to radioactively labelled albumin than the BBB of the brain and was not disrupted by 50 micrograms kg-1 of IL-1. 3. Capillary depletion showed that most of the I-IL entered the parenchymal-interstitial fluid space of the spinal cord with only a modest amount being sequestered by the endothelial cells of its BBB. 4. I-IL entered the cervical, thoracic and lumbar regions of the spinal cord equally well. I-IL entering at the brain and diffusing caudally was estimated only to account for about 1% of the total radioactivity found in the spinal cord after i.v. injection.(ABSTRACT TRUNCATED AT 250 WORDS)

Interleukin-1 beta (IL-1 beta) binds to intact porcine thyroid follicles, decreases iodide uptake but has no effect on cAMP formation or proliferation

Interleukin-1 beta (IL-1 beta) is known to be involved in autoimmune thyroiditis. Since the results of different in vitro-studies on the effect of IL-1 on thyrocytes are controversial, our aim was to investigate the existence of specific binding sites for IL-1 beta and its influence on specific functions and growth of isolated porcine thyroid follicles ex vivo with a preserved iodide metabolism. For binding studies isolated thyroid follicles were incubated with 125I-IL-1 beta (213.5 nCi/ml) and with increasing concentrations of unlabelled IL-1 beta (0.06-11.5 nmol/l) for 24 h at 4 degrees C. The dissociation constant Kd was 0.85 x 10(-10) mol/l and about 800 binding sites per cell were calculated. IL-1 beta (10 U/ml) decreased basal and TSH-stimulated iodide uptake and organification after an incubation time of 45 min to 6 h without any influence on cAMP-formation. In addition, after 40 h of incubation IL-1 beta dose-dependently increased T3-secretion, followed by a decrease during simultaneous TSH-stimulation, whereas there was no effect on T4-secretion. In contrast to these functional effects IL-1 beta showed no influence on the growth of thyroid follicles, so that the cytokine cannot be made responsible for goiter growth in thyroid diseases by directly influencing thyroxytes.

Induction, transcription, synthesis, and adsorption of interleukin-1 by dialyzer membranes

This study was designed to dissect the direct effect of dialyzer membrane on interleukin-1 (IL-1) induction from those of complement activation, mechanical stimulation, acetate/bicarbonate and endotoxin diffusion, and cell type interactions. To this end, a suspension of P388D1 murine macrophages in a complement-free culture medium containing 10% heat-inactivated serum, a closed-loop system consisting of tubing alone or with a hollow-fiber cuprammonium cellulose (CU) or polyacrylonitrile (PAN) dialyzer, and a roller pump were used. The dialysate compartment was filled with the same medium and capped. Cell suspension was recirculated at 300 mL/min for 3 h. Cells and supernates were separated, and adhering proteins were eluted. All samples tested negative for endotoxin. IL-1 mRNA was greatest with CU, followed by PAN and tubing alone. IL-1 in the supernate was greater with CU than with either tubing alone or PAN (P < 0.005; analysis of variance), which showed comparable values. IL-1 eluted from loops was greatest with PAN dialyzers, followed by sets with CU dialyzers and tubing alone (P < 0.001; analysis of variance). Thus, both CU and PAN membranes directly induce IL-1. However, avid adsorption by PAN attenuates the rise in circulating IL-1.

Quantification of recombinant human interleukin-1 alpha by a specific two cell immunobioassay

The detection of picogram quantities of recombinant human IL-1 alpha in human and rat serum was accomplished by a sensitive and specific two cell immunobioassay. The specificity is provided by an IL-1 alpha specific mouse IgM monoclonal antibody which is non-neutralizing thus allowing for the addition of the EL-4 NOB-1 cell line directly to the IL-1 alpha monoclonal antibody complex. The above cell line is then converted to an IL-2 producer line in response to the captured IL-1 alpha. Supernatant from the EL-4 NOB-1 cells is then added to the IL-2 dependent CTLL-2 line and cell proliferation measured by thymidine incorporation. This assay has the advantage of specificity provided by the antibody capture step, sensitivity provided by the EL-4 NOB-1 line (1-50 pg/ml) and finally ease of maintenance of the responder cell line which requires no feeder cells or mitogens. Data are reported on the sensitivity, precision, reproducibility and specificity of the assay, the stability of rhIL-1 alpha in serum and the recovery of rhIL-1 alpha from serum. We also report on the use of this procedure to assay samples from rats given ascending doses of rhIL-1 alpha.

Transfer of cytokines through human fetal membranes

Intact human fetal membranes (amnion, chorion and decidua) were incubated with 125I-labelled cytokines added to the fetal or maternal sides of the membrane. The transfer of 125I-labelled interleukin-6 (IL-6), 125I-labelled tumour necrosis factor alpha (TNF-alpha), 125I-labelled interleukin-1 alpha (IL-1 alpha) and 125I-labelled interleukin-1 beta (IL-1 beta) was determined by measurement of radioactivity in a gamma counter and the integrity of the cytokines was assessed by acid precipitation and by radioimmunoassay. IL-1 alpha and IL-1 beta were transferred through human fetal membranes in both feto-maternal and materno-fetal directions at similar rates. Only 2-4% of the cytokine originally added appeared to be intact on the opposing side of the membrane after 24 h of culture. Transfer of intact TNF-alpha (5-7%) and IL-6 (8-17%) was greater than that of the IL-1 isomers. Low but variable amounts of the four cytokines tested may be transferred through the human fetal membrane. This finding suggested that concentrations of cytokines in amniotic fluid would not reflect those produced by decidua if the fetal membranes are intact.

ELISA determination and preliminary pharmacokinetics of modified human rIL-1 beta in dogs

A single dose pharmacokinetic study with modified human Interleukin-1 Beta (IL-1 beta or DuP 118) was performed by injecting 5 micrograms/kg of drug into the jugular vein of three beagle dogs. Serial 5-ml plasma samples were removed from the dogs over a 120-minute period. DuP 118 plasma levels were measured using a sandwich ELISA technique capable of measuring concentrations ranging from 0.25 to 2 ng/ml with accuracy and precision constraints of less than +/- 20% variability. DuP 118 stored at -20 degrees C in dog plasma was stable for at least 1 month. Pharmacokinetic parameters were determined for the three dogs by standard model independent or non-compartmental methods. DuP 118 was rapidly distributed in the dog. The volume of distribution was approximately two-fold higher than the total body water of a lean dog. The terminal half-life was short, less than 30 minutes. Within approximately an hour after dosing, DuP 118 plasma levels were reduced 20-fold and were below the quantifiable limit of the assay.

Synergistic antiproliferative effects of interleukin-1 alpha and doxorubicin against the human ovarian carcinoma cell line (NIH:OVCAR-3)

Interleukin-1 alpha (IL-1 alpha) exerts antiproliferative effects on a human ovarian carcinoma cell line, NIH:OVCAR-3, which is resistant to clinically relevant concentrations of doxorubicin (DOX) and other chemotherapeutic agents. This action of IL-1 alpha depends on the presence of type I (80 kDa) receptors, although no quantitative relationship has been established between receptor occupancy and inhibition of cell growth. When NIH:OVCAR-3 cells were exposed to IL-1 alpha and DOX in combination, a mutual potentiation of the antiproliferative effects of the two agents was observed. This synergistic effect was not due to IL-1 receptor expression up-regulation by DOX, and receptor-dependent internalization of the cytokine was also unaffected. The involvement of IL-1 receptors is supported by the observation that synergism between the two agents was diminished (but not abolished) in the presence of a specific IL-1 receptor antagonist at concentrations blocking more than 75% of IL-1 alpha binding. DOX was found to significantly increase IL-1 alpha accumulation by NIH:OVCAR-3 cells after long-term (48 hr) exposure to the cytokine at 37 degrees, which might be due to increased nonspecific fluid phase uptake or to interference with cytokine degradation and/or release processes. The potent synergy of IL-1 alpha and DOX against ovarian carcinoma cells in vitro suggests that this drug combination may be effective against this disease in the clinic.

Adjuvant effect of interleukin-1 on the development of late asthmatic response in guinea pigs

The adjuvant effect of silica and IL-1 in the development of late asthmatic responses (LARs) in guinea pigs was studied. Different doses of silica or recombinant human (rh) IL-1 (1 microgram) with Ascaris suum were used for the immunization. The serum IL-1 concentration was measured after the immunization. One week after the immunization, antigen was challenged and respiratory resistance (Rrs) was measured. Rrs increased silica dose dependently in the late phase, and the increment of Rrs in the late phase was significantly correlated with the serum IL-1 concentration (p < 0.05). In addition, rhIL-1 administration showed an increase in Rrs at the late phase. Antigen-specific IgE and IgG1 were also measured and were increased in guinea pigs immunized both with silica and rhIL-1.

Human interleukin-1 alpha crosses the blood-testis barriers of the mouse

Interleukin-1 alpha (IL-1 alpha) has been shown to have direct effects on the gonads, affecting steroidal secretion, DNA synthesis by spermatogonia, and the immune function of the testes. It is unclear, however, how IL-1 alpha exerts these effects because the testis is partitioned into basal and adluminal compartments by both a vascular and a Sertoli cell barrier. The authors used a highly sensitive method to quantify the unidirectional flux rates (Ki) into the testis of technetium pertechnetate-labeled human albumin (T-alb), a compound that does not readily cross the vascular barrier, and human IL-1 alpha radioactively labeled with 125I (I-IL). The entry rate (Ki) was almost six times greater for I-IL than for T-alb. Part of the enhanced entry of I-IL was due to a saturable transport system. Nearly 0.2% of the total injection had entered the testes 60 minutes after intravenous administration, and more than 75% of that amount was not accounted for by the albumin space. Collection of testicular interstitial fluid from the basal compartment and seminiferous tubule fluid from the adluminal compartment showed preferential entry of I-IL into these compartments. Analysis by high-pressure liquid chromatography or radioactivity recovered from the testis showed that intact I-IL was entering the testis. The leakiness of the blood-testis barrier was measured by the rate of entry for T-alb, which was not altered by injection of unlabeled human IL-1 alpha in doses of up to 50 micrograms/kg (5 x 10(6) U/kg), and by the wet weight of the testes. The results show that circulating IL-1 alpha can have direct access to the testis, supporting previous studies suggesting a direct effect of IL-1 alpha on gonadal function.

Human interleukin (IL) 1 alpha, murine IL-1 alpha and murine IL-1 beta are transported from blood to brain in the mouse by a shared saturable mechanism

Interleukins (ILs) 1 alpha and 1 beta are important components of the neuroimmune axis. Recent work has shown that human 125I-IL-1 alpha can enter the brain from the blood by a saturable system, suggesting a mechanism that may directly link the immune and nervous systems. Here, it is shown that radioiodinated murine IL-1 beta and especially murine IL-1 alpha are even more rapidly transported into the brain of the mouse than is radioiodinated human IL-1 alpha after i.v. injection. All three cytokines exhibited self-inhibition, thus demonstrating saturable transport. Also, they all cross-inhibited the transport of each other. This shows that there are not three separate transport systems, but that they either share transport systems with overlapping affinities or share a single system. It was calculated that 0.06% to 0.08% of the dose of human 125I-IL-1 alpha injected i.v. was present in the brain during the first 60 min. By contrast, no saturable component could be detected in the brain to blood passage of the three ILs. No disruption of the blood-brain barrier to radioactively labeled albumin was found with i.v. doses of up to 50 micrograms/kg of human IL-1 alpha. Additional studies on the blood to brain transport of human 125I-IL-1 alpha showed no modification by dexamethasone, morphine, indomethacin or alpha-melanocyte stimulating hormone. Studies with antibodies directed toward the binding or nonbinding sites of IL or its receptor on the murine T lymphocyte suggest similar, but not identical, structural requirements for transport and for receptor binding.(ABSTRACT TRUNCATED AT 250 WORDS)

The pharmacokinetics, distribution and degradation of human recombinant interleukin 1 beta in normal rats

Based upon in vivo rat experiments it was recently suggested that interleukin 1 in the circulation may be implicated in the initial events of beta-cell destruction leading to insulin-dependent diabetes mellitus (IDDM) in humans. The aim of the present study was to estimate half-lives of distribution (T1/2 alpha) and elimination phases (T1/2 beta) of human recombinant interleukin 1 beta (rIL-1 beta), and its tissue distribution and cellular localization by means of mono-labelled, biologically active 125I-rIL-1 beta. After intravenous (i.v.) injection, 125I-rIL-1 beta was eliminated from the circulation with a T1/2 alpha of 2.9 min and a T1/2 beta of 41.1 min. The central and peripheral volume of distribution was 20.7 and 19.1 ml/rat, respectively, and the metabolic clearance rate was 16.9 ml/min/kg. The kidney and liver showed the highest accumulation of tracer, and autoradiography demonstrated that 125I-rIL-1 beta was localized to the proximal tubules in the kidney and to the hepatocytes in the liver. Furthermore, grains were localized to the islets of Langerhans in the pancreas. Tracer-bound proteins corresponding to intact 125I-rIL-1 beta were found in the circulation after i.v., intraperitoneal (i.p.) and subcutaneous (s.c.) injections, as demonstrated by high performance size exclusion chromatography, trichloracetic acid precipitation and SDS-PAGE until 5 h after tracer injection. Pre-treatment with 'cold' rIL-1 beta enhanced degradation of a subsequent injection of tracer. The route of administration was of importance for the biological effects of rIL-1 beta, as demonstrated by a reduced food intake, increased rectal temperature and blood glucose after s.c. injection of rIL-1 beta compared with i.p. The present demonstration of intact rIL-1 beta in the circulation and the islets of Langerhans supports the hypothesis that systemic IL-1 beta may be involved in the initial beta-cell destruction leading to IDDM in humans.

Repeated intraperitoneal injections of interleukin 1 beta induce glucose intolerance in normal rats

Previous in vitro findings suggest the involvement of interleukin 1 (IL-1) in the pathogenesis of insulin-dependent diabetes mellitus. The aims of the present study were to investigate the effects of single or repeated ip injections of recombinant IL-1 beta on blood glucose and glucose tolerance in vivo. Normal Wistar Kyoto rats were injected ip with a single injection of 4 micrograms/kg of the mature form of recombinant IL-1 beta (amino acids 117-269) or once daily on 5 consecutive days. Control rats were given vehicle and were fed ad libitum or pair-fed together with the rIL-1 beta treated rats. An ip glucose tolerance test (0.2 g D-glucose/100 g) was performed 2 h after injection of rIL-1 beta. A single injection of rIL-1 beta caused a mild depression in blood glucose and an improved glucose tolerance. Multiple injections of rIL-1 beta induced a diminished weight gain, a 24-28% reduction in food intake, a lasting mild depression of blood glucose (7 days) and a transiently impaired glucose tolerance on day 5. We conclude that systemic IL-1 should be considered an important regulator of glucose homeostasis in vivo.

Blood to brain transport of interleukin links the immune and central nervous systems

Interleukins (IL) are naturally occurring proteins that regulate, and thus link, both the immune system and the central nervous system (CNS). Since proteins are assumed not to be able to cross the blood-brain barrier (BBB), it is controversial how this linkage could occur. We show here that after iv injection of 125I-hIL-1 alpha, radioactivity in the brain eluted on HPLC in the position of the labeled cytokine. In addition, entry was inhibited by unlabeled hIL-1 alpha. Our demonstration of a saturable, carrier-mediated system that transports recombinant human IL-1 alpha in intact form from the blood into the CNS indicates a direct immune-CNS connection.

Cytokine administration alters the distribution of activated lymphocytes to the lung

The effects of intraperitoneal injections of recombinant interleukin-1 alpha (IL-1; 250,000 U/day), interleukin-2 (IL-2; 50,000 units/day), interferon-gamma (IFN-gamma; 50,000 U/day) and tumor necrosis factor-alpha (TNF; 100,000 U/day), on the biodistribution of concanavalin A (Con A)-activated, indium-111-labeled lymphocytes were evaluated in BALB/c mice. Syngeneic spleen cells were activated for 48 h in medium with Con A (5 micrograms/ml) and maintained in culture for 72 h in IL-2 (1,000 U/ml). Groups of 12 mice were treated for 4 days with either one of the cytokines or saline. On day 4, mice received 10(7) lymphocytes (3-5 mu Ci) intravenously. Mice were sacrificed at 4 and 24 h following injection and the percent of administered dose per organ was determined. TNF and IL-1 produced a significant increase in lung uptake of radiolabeled lymphocytes at 4 and 24 h, whereas IL-2 and IFN-gamma decreased uptake at both time points. IL-1 increased uptake by liver at 4 and 24 h while IL-2 increased uptake only at 4 h. We conclude that the distribution of activated lymphocytes following adoptive transfer is altered by cytokines. This finding may have important implications for cell delivery during adoptive immunotherapy.

Fate of injected interleukin 1 in rats: sequestration and degradation in the kidney

The tissue distribution and route of clearance of human recombinant interleukin 1 alpha (IL 1 alpha) injected intravenously in rats was studied. The plasma half-life was approximately 2.5 min, and this was increased after nephrectomy, the kidney being the major organ through which the IL 1 alpha was excreted. Two iodinated fragments of IL 1 alpha, of approximately 5 and 9 kDa, were excreted by the kidneys whereas only intact, 17-kDa IL 1 alpha was detected in plasma, suggesting that the protein was being degraded after uptake by the kidney. The results of in vivo experiments in which surface endopeptidase-24.11 was inhibited with phosphoramidon and in vitro experiments in which rat kidney homogenates were incubated with radiolabeled IL 1 alpha suggest that the cytokine was endocytosed and then hydrolysed by lysosomal proteinases.

The release of interleukin-1 beta, tumor necrosis factor-alpha and interferon-gamma by cultured peripheral blood mononuclear cells from patients with periodontitis

The extracellular release of IL-1 beta by cultured peripheral blood monocytes from 26 periodontitis patients and 26 control subjects was measured by radioimmunoassay. Unstimulated monocytes from periodontitis patients released significantly more IL-1 beta than controls during 24 h of culture; there was a wide variation in the amount of IL-1 beta released (0.45-13.00 ng/ml per 10(6) cells) which did not correlate with either the degree of bone loss or pocket formation observed clinically. When stimulated with lipopolysaccharide (LPS; Actinobacillus actinomycetemcomitans; 5 micrograms/ml) monocytes from periodontitis patients produced significantly more IL-1 beta than those from control subjects. Monocyte culture supernatants from another 10 periodontitis patients and 10 control subjects were also assayed for both IL-1 beta and TNF-alpha by enzyme-linked immunosorbent assays. Spontaneous and LPS-stimulated (Bacteroides gingivalis; 5 micrograms/ml) IL-1 beta release were again significantly higher for periodontitis patients. TNF-alpha was detected in the periodontitis cultures (0-765 pg/ml per 10(6) cells), but the mean value was not significantly different from controls. LPS-stimulated TNF-alpha release, however, was significantly higher than for control subjects, and there was a strong correlation between spontaneous IL-1 beta and TNF-alpha release by monocytes from the periodontitis group. Measurement of interferon-gamma (IFN-gamma) in lymphocyte cultures from these patients by immunoradiometric assay showed that IFN-gamma levels in periodontitis cultures were consistently low, but not significantly so when compared to controls; both groups responded equally to concanavalin-A (5 micrograms/ml). Although the precise roles of IL-1 beta and TNF-alpha in periodontitis remain unclear, these data provide evidence that both cytokines may participate in the pathogenesis of the disease.

Interleukin-1 beta but not interleukin-1 alpha, induces acute inflammation-like changes in the testicular microcirculation of adult rats

A number of inflammatory mediators and cytokines were injected locally into the testis of adult rats in order to test their ability to induce leukocyte accumulation and increased vascular permeability (as studied by a carbon labelling technique). Human recombinant interleukin-1 beta (IL-1 beta) caused increased vascular permeability and leukocyte migration. All the other factors studied--histamine, serotonin, bradykinin, interleukin-1 alpha (IL-1 alpha), and a partially purified interleukin-1 alpha-like factor (tIL-1) from rat testis--did not induce any acute signs of increased vascular permeability or inflammatory response after local injection. It is suggested that local production of IL-1 beta from testicular macrophages could be responsible for the inflammation-like changes that are seen in rat testes after treatment with human chorionic gonadotrophin.