Interleukin-1 mediates endothelin-1-induced fever and prostaglandin production in the preoptic area of rats

The intracerebroventricular injection of endothelin-1 (ET-1) induces fever and increases PG levels in the cerebrospinal fluid of rats. Likewise, the injection of IL-1 into the preoptic area (POA) of the rat hypothalamus causes both fever and increased PG production. In this study, we conducted in vivo and in vitro experiments in the rat to investigate 1) the hypothalamic region involved in ET-1-induced fever and PG biosynthesis and 2) whether hypothalamic IL-1 plays a role as a mediator of the above ET-1 activities. One hundred femtomoles of ET-1 increased body temperature when injected in the POA of conscious Wistar rats; this effect was significantly counteracted by the coinjection of 600 pmol IL-1 receptor antagonist (IL-1ra). In experiments on rat hypothalamic explants, 100 nM ET-1 caused a significant increase in PGE2 production and release from the whole hypothalamus and from the isolated POA, but not from the retrochiasmatic region, in 1-h incubations. Six nanomoles of IL-1ra or 10 nM of a cell-permeable interleukin-1 converting enzyme inhibitor completely counteracted the effect of ET-1 on PGE2 release from the POA. One hundred nanomoles ET-1 also caused a significant increase in IL-1beta immunoreactivity released into the bath solution of hypothalamic explants after 1 h of incubation, although during such time ET-1 failed to modify the gene expression of IL-1beta and other pyrogenic cytokines within the hypothalamus. In conclusion, our results show that ET-1 increases IL-1 production in the POA, and this effect appears to be correlated to ET-1-induced fever in vivo, as well as to PG production in vitro.     

Identification of a high-affinity receptor for interleukin-1 beta in rat brain

A single type of high-affinity binding sites for IL-1 beta was identified in the rat hypothalamus (Kd = 1.0 +/- 0.2 nM) and cerebral cortex (Kd = 1.3 +/- 0.2 nM), but not in the pituitary. The maximum binding capacity (Bmax) in the hypothalamus (Bmax = 75.4 +/- 10.8 fmol/mg protein) was 4 times greater than in the cerebral cortex (Bmax = 17.2 +/- 1.5 fmol/mg protein). Neither various neuropeptides nor IL-2 appeared to influence the binding of [125I]IL-1 beta to the hypothalamic membrane preparations. The potency of unlabeled IL-1 alpha to replace the binding of [125I]IL-1 beta to the hypothalamic membrane preparations was considerably less than that of unlabeled IL-1 beta. These findings indicate that IL-1 beta receptors are heterogeneously distributed in the central nervous system and that IL-1 alpha does not bind with IL-1 beta receptors in the brain.     

Detection of interleukin 1 alpha and 1 beta in rabbit tissues during endotoxemia using sensitive radioimmunoassays.

Interleukin 1 (IL-1) is a primary mediator of a wide variety of immunologic and inflammatory responses, including reactions to microbial infections. To study this cytokine in an animal model, we have developed specific and sensitive radioimmunoassays for the quantitation of rabbit IL-1 alpha and IL-1 beta. The sensitivity (limit of detection at 95% confidence level) of our assay for IL-1 alpha and 1 beta was 20-40 and 40-80 pg/ml, respectively. Recovery of IL-1 from tissues ranged from 75 to 107%, with a mean of 95% for IL-1 alpha and 89% (range 19-98) for IL-1 beta. We employed these assays in in vivo and in vitro studies. In an in vivo model, we measured the amount of rabbit IL-1 alpha and 1 beta protein present in brain, kidney, liver, lung, muscle, and spleen at various times after the injection of endotoxin. IL-1 was found in all tissues studied but largely in the spleen; IL-1 levels were transient, reaching peak levels by 4 h after injection of endotoxin and rapidly decreasing to low levels by 24 h. In similar in vitro studies, IL-1 alpha levels reached peak elevation 6 h after addition of endotoxin, whereas IL-1 beta was maximal at 24 h. IL-1 alpha was detected in all tissues; IL-1 beta was observed primarily in lung, kidney, and spleen. These studies establish the presence of IL-1 in various tissues during endotoxemia.     

Role of hypothalamic interleukin-1beta (IL-1beta) in regulation of energy homeostasis by melanocortins

In the current study we sought to determine whether hypothalamic IL-1beta is regulated by melanocortin signaling and if melanocortin-induced changes in energy balance are dependent on IL-1beta. A melanocortin agonist, MTII, increased hypothalamic IL-1beta mRNA levels by two-fold, whereas a melanocortin antagonist, SHU9119, blunted lipopolysaccharide (LPS)-mediated increase of hypothalamic IL-1beta content. Pharmacological or genetic disruption of IL-1 receptor signaling prevented MTII-mediated reductions in locomotor activity, but did not reduce MTII-induced anorexia. These data suggest a potential role for central melanocortins in mediating the decrease of ambulation characteristic of the 'sickness' response.     

Central administration of a nitric oxide precursor abolishes both the hypothalamic serotonin release and the hypophagia induced by interleukin-1beta in obese Zucker rats

Serotonin-induced anorexia has long been recognized as an important part of the CNS mechanisms controlling energy balance. More recently, interleukin-1beta and nitric oxide have been suggested to influence this control, possibly through modulation of hypothalamic serotonin. The present work aimed at investigating the interaction of these systems. We addressed whether 5-HT is affected during IL-1beta-induced anorexia in obese Zucker rats and the influence of the central NO system on this IL-1beta/5-HT interaction. Using microdialysis, we observed that an intracerebroventricular injection of 10 ng IL-1beta significantly stimulated 5-HT extracellular levels in the VMH, with a peak variation of 102+/-41% above baseline. IL-1beta also significantly reduced the 4-h feeding by 33% and the 24-h feeding by 42%. Contrarily, these effects were absent when IL-1beta was injected 2 h after the i.c.v. administration of 20 microg of the NO precursor L-arginine. The results suggest that, in obese Zucker rats, activation of the serotonergic system in the medial hypothalamus participates in IL-1beta-induced anorexia. Since L-arginine, probably through NO stimulation, abolished both the anorexia and the serotonergic activation, it can be proposed that the NO system, either directly or indirectly, counteracts IL-1beta anorexia. The hypothalamic serotonergic system is likely to mediate this NO effect.     

Virus-induced interferon alpha/beta (IFN-alpha/beta) production by T cells and by Th1 and Th2 helper T cell clones: a study of the immunoregulatory actions of IFN-gamma versus IFN-alpha/beta on functions of different T cell populations

Spleen cells, resting T cells, activated T cells, and T cell clones characterized as type 1 (Th1) and type 2 (Th2) were investigated for their ability to produce interferon (IFN) following in vitro culture with Newcastle disease virus (NDV). All of the above cell populations, including both Th1 and Th2 T cell clones, produced high levels of IFN following in vitro culture with NDV. This IFN was characterized as a mixture of IFN-alpha and IFN-beta with IFN-alpha being the predominate species of IFN contained in the mixture. IL-2 greatly enhanced the production of IFN-alpha/beta by all cell populations in response to NDV. These different T cell populations responded very differently to the immunoregulatory actions of IFN-gamma versus IFN-alpha/beta. IFN-alpha/beta was shown to be a potent inhibitor of Con A or IL-2-induced proliferation of different T cell populations. This inhibition was not associated with a reduction in lymphokine production since spleen cells or Th1 T cell clones cultured with Con A and IFN-alpha/beta had no decrease in IL-2 or IFN-gamma production when compared to Con A-stimulated control cultures. IFN-gamma had little to no inhibitory activity on Con A-induced proliferation of spleen cells. In fact, Con A-induced proliferation was usually enhanced by IFN-gamma when nylon wool-enriched T cells were assessed. Different results were observed when IFN-gamma and IFN-alpha/beta were investigated for their ability to inhibit IL-2-induced proliferation of different T helper cell clones. IFN-gamma and IFN-alpha/beta were both capable of inhibiting IL-2-induced proliferation of T cell clones characterized as type 2 (Th2). In contrast, IFN-gamma had no effect on IL-2-induced proliferation of Th1 clones. IFN-alpha/beta, however, inhibited IL-2-induced proliferative responses of both Th1 and Th2 T cell clones. These results document the facts that (1) IFN-gamma and IFN-alpha/beta differ in their immunoregulatory actions, (2) different T cell subpopulations vary in their susceptibility to IFN-gamma regulation, and (3) virus induction of IFN-alpha/beta appears to be a ubiquitous function associated with different T cell populations.     

Role of interleukin-1β, interleukin-6 and macrophage inflammatory protein-1β in prostaglandin-E2-induced hyperthermia in rats

The purpose of this study was to investigate the role of pyrogenic cytokines, such as IL-1β, IL-6 and MIP-1β, in the mechanisms underlying the hyperthermic response of rats to central injection of PGE₂. Thus, specific murine neutralizing antibodies against these cytokines were microinjected directly into the anterior hypothalamic, preoptic area (AH/POA) of unrestrained rats just before intracerebroventricular injection of PGE₂. The significant hyperthermia induced by PGE₂ was markedly suppressed by micro-injection of anti-IL-6 and partially attenuated by anti-IL-1β. However, the micro-injection of anti-MIP-1β failed to alter the hyperthermic response. The results indicate that PGE₂-induced hyperthermia is presumably mediated through actions of IL-6 on the thermosensitive cells of the AH/POA and confirm that distinct and alternate pathways exist in the rat brain for the induction of fever.     

Central activation of thermogenesis and fever by interleukin-1 beta and interleukin-1 alpha involves different mechanisms

Interleukin-1 exists in two forms (alpha and beta) which are assumed to act on the same receptor. Both forms of the molecule stimulated fever and thermogenesis in the rat when injected into the brain, but interleukin-1 beta was more effective, and combined injection of alpha and beta elicited additive responses. The actions of interleukin-1 beta were inhibited by pretreatment of the animals with either a receptor antagonist or monoclonal antibody to corticotrophin releasing factor. The effects of interleukin-1 alpha were unaltered by these treatments. The results indicate that brain corticotrophin releasing factor mediates thermogenesis and fever induced by interleukin-1 beta but not by interleukin-1 alpha.     

α-黑色素细胞刺激素对白细胞介素-1β发热的解热机理研究

本研究观察了α－黑色素细胞刺激素（α－ＭＳＨ）对家兔白细胞介素－１β（ＩＬ－１β）发热效应及下丘脑组织腺苷环－磷酸（ｃＡＭＰ）含量的影响;同时观察了下丘本外培养过程中,α－ＭＳＨ对ＩＬ－１β刺激下丘脑释放ｃＡＭＰ的影响。结果显示：α－ＭＳＨ能显著降低ＩＬ－１β引起的体温升高（Ｐ〈０．０５）;同时抑制下丘脑组织ｃＡＭＰ含量的增高（Ｐ〈０．０１）。ＩＬ－１β与下丘脑组织培养,其上清液的ｃＡＭＰ含量明显     

IL-1beta regulation of BDNF expression in rat cultured hypothalamic neurons depends on the presence of glial cells

In the present study, we have shown that IL-1beta increased BDNF mRNA expression in hypothalamic neuron-enriched cultures whereas it reduced this expression in mixed cultures, i.e. containing astrocytes and neurons. Because functional relationships between stress and immunity signals are well documented we investigated the possible interaction between BDNF and IL-1beta in hypothalamic neurons. Notably, we investigated whether IL-1beta affected BDNF expression in vitro either on hypothalamic mixed cultures or on neuron-enriched cultures. We found that the response to IL-1beta was stimulatory when directly examined in neurons but was inhibitory when astrocytes were present in the cultures. Since it has been documented that astrocytes release PGE2 in response to IL-1beta, we examined the effect of indomethacin (a PGE2 synthesis inhibitor) on mixed or neuron-enriched cultures treated with IL-1beta. Indomethacin blocked both stimulatory and inhibitory IL-1beta effects on BDNF mRNA expression whereas picrotoxin (a GABA(A) blocker) or MK-801 (a NMDA receptor blocker) had no effect on BDNF mRNA levels. About 3 and 6h treatments of cells with exogenous PGE2 reproduced the effects of IL-1beta on neuron-enriched or on mixed cultures suggesting that PGE2 was involved in BDNF mRNA regulation. Analysis of PGE2 receptors mRNA expression revealed that the PGE2 receptor pattern was changed when neuron-enriched cultures were treated with conditioned medium produced by astrocytes treated with IL-1beta. Thus, EP3 mRNA levels were increased while EP1 and EP4 messengers were unchanged. This increased expression of the inhibitory prostaglandin receptor under astrocyte influence can explain the inhibition of BDNF mRNA levels observed in mixed cultures following IL-1beta or PGE2 treatment. Finally, we demonstrated by immunocytochemistry that EP3 receptors had a neuronal localization in the hypothalamic cultures. Taken together, these data contribute to underline an emerging physiological concept postulating that a same molecule may have opposite effects as a function of the cellular context.     

Role of alpha(2)-macroglobulin in fever and cytokine responses induced by lipopolysaccharide in mice

Alpha(2)-macroglobulin (alpha(2)M) is not only a proteinase inhibitor in mammals, but it is also a specific cytokine carrier that binds pro- and anti-inflammatory cytokines implicated in fever, including interleukin (IL)-1beta, IL-6, and tumor necrosis factor-alpha (TNF-alpha). To define the role of alpha(2)M in regulation of febrile and cytokine responses, wild-type mice and mice deficient in alpha(2)M (alpha(2)M -/-) were injected with lipopolysaccharide (LPS). Changes in body temperature as well as plasma levels of IL-1beta, IL-6, and TNF-alpha and hepatic TNF-alpha mRNA level during fever in alpha(2)M -/- mice were compared with those in wild-type control mice. The alpha(2)M -/- mice developed a short-term markedly attenuated (ANOVA, P < 0.05) fever in response to LPS (2.5 mg/kg ip) compared with the wild-type mice. At 1.5 h after injection of LPS, the plasma concentration of TNF-alpha, but not IL-1beta or IL-6, was significantly lower (by 58%) in the alpha(2)M -/- mice compared with their wild-type controls (ANOVA, P < 0.05). There was no difference in hepatic TNF-alpha mRNA levels between alpha(2)M -/- and wild-type mice 1.5 h after injection of LPS. These data support the hypotheses that 1) alpha(2)M is important for the normal development of LPS-induced fever and 2) a putative mechanism of alpha(2)M involvement in fever is through the inhibition of TNF-alpha clearance. These findings indicate a novel physiological role for alpha(2)M.     

IL-1beta and LPS induce anorexia by distinct mechanisms differentially dependent on microsomal prostaglandin E synthase-1

Recent work demonstrated that the febrile response to peripheral immune stimulation with proinflammatory cytokine IL-1beta or bacterial wall lipopolysaccharide (LPS) is mediated by induced synthesis of prostaglandin E(2) by the terminal enzyme microsomal prostaglandin E synthase-1 (mPGES-1). The present study examined whether a similar mechanism might also mediate the anorexia induced by these inflammatory agents. Transgenic mice with a deletion of the Ptges gene, which encodes mPGES-1, and wild-type controls were injected intraperitoneally with IL-1beta, LPS, or saline. Mice were free fed, and food intake was continuously monitored with an automated system for 12 h. Body weight was recorded every 24 h for 4 days. The IL-1beta induced anorexia in wild-type but not knock-out mice, and so it was almost completely dependent on mPGES-1. In contrast, LPS induced anorexia of the same magnitude in both phenotypes, and hence it was independent of mPGES-1. However, when the mice were prestarved for 22 h, LPS induced anorexia and concomitant body weight loss in the knock-out animals that was attenuated compared with the wild-type controls. These data suggest that IL-1beta and LPS induce anorexia by distinct immune-to-brain signaling pathways and that the anorexia induced by LPS is mediated by a mechanism different from the fever induced by LPS. However, nutritional state and/or motivational factors also seem to influence the pathways for immune signaling to the brain. Furthermore, both IL-1beta and LPS caused reduced meal size but not meal frequency, suggesting that both agents exerted an anhedonic effect during these experimental conditions.     

Both interleukin-1 alpha and interleukin-1 beta are involved as accessory signals in primary antigen (tetanus toxoid) induced human T-cell activation

The function of interleukin-1 alpha and interleukin-1 beta (IL-1 alpha, IL-1 beta) in tetanus toxoid (TT) induced T-cell proliferation in cultures of peripheral blood mononuclear cells (PBL) obtained from healthy donors was assessed by using neutralizing antisera to IL-1 alpha and IL-1 beta. The neutralizing capacity and the specificity of the IL-1 antisera were tested by the use of the thymoma EL-4 NOB-1 cell line. Antisera to IL-1 beta effectively neutralized the proliferative capacity of human recombinant IL-1 beta but not of human recombinant IL-1 alpha and vice versa. Addition of either anti-IL-1 beta or anti-IL-1 alpha antiserum to the culture medium hardly affected TT induced T-cell proliferation. However, the proliferative T-cell response was consistently attenuated when a combination of IL-1 alpha and IL-1 beta antiserum was used. The antisera were never capable of completely abolishing the T-cell response to TT. We conclude that (a) IL-1 alpha and IL-1 beta are both necessary accessory signals for T-cell proliferation to antigen in vitro; (b) in T-cell proliferation IL-1 alpha and IL-1 beta are interchangeable; and (c) T-cell proliferation to antigen is only partially dependent on IL-1 as signal.     

Short day lengths attenuate the symptoms of infection in Siberian hamsters

Symptoms of infection, such as fever, anorexia and lethargy, are ubiquitous among vertebrates. Rather than nonspecific manifestations of illness, these responses are organized, adaptive strategies that are often critical to host survival. During times of energetic shortage such as winter, however, it may be detrimental for individuals to prolong energetically demanding symptoms such as fever. Individuals may adjust their immune responses prior to winter by using day length to anticipate energetically-demanding conditions. If the expression of sickness behaviours is constrained by energy availability, then cytokine production, fever, and anorexia should be attenuated in infected Siberian hamsters housed under simulated winter photoperiods. We housed hamsters in either long (14 L : 10 D) or short (10 L : 14 D) day lengths and assessed cytokines, anorexia and fever following injections of lipopolysaccharide (LPS). Short days attenuated the response to lipopolysaccharide, by decreasing the production of interleukin (IL)-6 and IL-1beta, and diminishing the duration of fever and anorexia. Short-day exposure in hamsters also decreased the ingestion of dietary iron, a nutrient vital to bacterial replication. Taken together, short day lengths attenuated the symptoms of infection, presumably to optimize energy expenditure and survival outcome.     

Effect of in vitro interferon treatment on the rapid clearance of murine leukemia cells in vivo.

Previous work showed that interferon (IFN) can protect target cells from NK mediated lysis in vitro. In the present study we investigate the effect of IFN alpha/beta or IFN gamma treatment of three different murine leukemia cell lines. For this purpose FLC-745 (susceptible to the antiproliferative activity of IFN alpha/beta and gamma), FLC-3C18 (IFN alpha/beta -resistant and IFN gamma - susceptible) of DBA/2 origin and EL-4 (IFN alpha/beta - susceptible and IFN gamma - resistant) leukemia of C57B1/6 origin were treated with IFN alpha/beta or gamma in vitro and assayed for their susceptibility to natural resistance measured in vivo as organ rapid clearance 4 hr after iv injection into syngeneic mice. Using young or Poly I:C stimulated hosts, but not mice with low levels of natural resistance (i.e. older animals or mice treated with cyclophosphamide), slower elimination of treated cells was observed with: (a) FLC-745 cells treated with IFN alpha/beta and IFN gamma and (b) FLC 3C18 treated with IFN gamma. Such a delayed clearance was not observed with: (a) FLC-3C18 cells treated with IFN alpha/beta and (b) EL-4 leukemia cells preincubated with IFN alpha/beta or IFN gamma. These results suggest that under selected conditions IFNs can protect leukemic cells from in vivo natural reactivity.     

Suppressor T cell activation by human leukocyte interferon

Murine fibroblast interferon (IFN beta) activates murine suppressor T lymphocytes in vitro, which suppress plaque-forming cell responses by spleen cells. Suppression of human in vitro immune responses by IFN was investigated to determine whether human IFN also activates suppressor T cells. Human leukocyte IFN (IFN alpha) suppressed pokeweed mitogen-induced polyclonal immunoglobulin production by human peripheral blood mononuclear cells (PBMC) by 80 to 90% at doses of 200 to 350 U/ml. Responses by IFN alpha-treated PBMC were suppressed in a dose-dependent manner; control cultures had maximal responses on day 7. PBMC incubated with 10,000 U/ml of IFN alpha contained activated suppressor cells that decreased pokeweed mitogen-stimulated, polyclonal immunoglobulin production by autologous cells by 70 to 80%. Suppression mediated by these cells was prevented by catalase, ascorbic acid, and 2-mercaptoethanol (2-ME). In murine systems, these reagents interfere with expression of suppressor T cell activity by preventing activation of soluble immune response suppressor. Selection procedures with monoclonal antibodies identified the suppressor cell as an OKT8+ (suppressor/cytotoxic) T lymphocyte. Selected OKT8+ cells required less IFN alpha (1000 U/ml) for activation and were effective in smaller numbers than unfractionated activated PBMC. IFN alpha-activated suppressor cells also inhibited proliferation in mixed lymphocyte and mitogen-stimulated PBMC cultures; again, catalase and 2-ME blocked suppression. These results indicate that IFN alpha activates suppressor T cells in human PBMC cultures; the ability of catalase, 2-ME, and ascorbic acid to block suppression suggests that these suppressor T cells have certain similarities to IFN beta or to concanavalin A-activated murine suppressor T cells.     

IFN-lambda (IFN-lambda) is expressed in a tissue-dependent fashion and primarily acts on epithelial cells in vivo

Interferons (IFN) exert antiviral, immunomodulatory and cytostatic activities. IFN-alpha/beta (type I IFN) and IFN-lambda (type III IFN) bind distinct receptors, but regulate similar sets of genes and exhibit strikingly similar biological activities. We analyzed to what extent the IFN-alpha/beta and IFN-lambda systems overlap in vivo in terms of expression and response. We observed a certain degree of tissue specificity in the production of IFN-lambda. In the brain, IFN-alpha/beta was readily produced after infection with various RNA viruses, whereas expression of IFN-lambda was low in this organ. In the liver, virus infection induced the expression of both IFN-alpha/beta and IFN-lambda genes. Plasmid electrotransfer-mediated in vivo expression of individual IFN genes allowed the tissue and cell specificities of the responses to systemic IFN-alpha/beta and IFN-lambda to be compared. The response to IFN-lambda correlated with expression of the alpha subunit of the IFN-lambda receptor (IL-28R alpha). The IFN-lambda response was prominent in the stomach, intestine and lungs, but very low in the central nervous system and spleen. At the cellular level, the response to IFN-lambda in kidney and brain was restricted to epithelial cells. In contrast, the response to IFN-alpha/beta was observed in various cell types in these organs, and was most prominent in endothelial cells. Thus, the IFN-lambda system probably evolved to specifically protect epithelia. IFN-lambda might contribute to the prevention of viral invasion through skin and mucosal surfaces.     

A warmer ambient temperature increases the passage of interleukin-1beta into the brains of old rats

We have demonstrated that after intraperitoneal lipopolysaccharide (LPS) injection, old rats mount fevers similar to those of young rats at an ambient temperature (Ta) of 31 degrees C, but not at 21 degrees C. The same is true for intraperitoneal or intravenous IL-1beta administration. The underlying mechanism responsible for blunted fever in old rats may be a deficiency in communication between the periphery and the brain. Possibly, peripheral cytokine actions are altered in old rats, such that the signal that reaches the brain is diminished. Here, we hypothesized that at standard laboratory temperatures, not enough IL-1beta is reaching the brain for fever to occur and that a warmer Ta would increase the influx of IL-1beta into the brain, enabling old rats to generate fever. Young (3-5 mo) and old (23-29 mo) Long-Evans rats were maintained for 3 days at either Ta 21 or 31 degrees C prior to intravenous injection with radiolabeled IL-1beta to measure passage across the blood-brain barrier. Young rats showed similar influx of IL-1beta into the brain at the two Tas, but old rats showed significant influx only at the warmer Ta. These data suggest that the lack of fever at a cool Ta may be due to a reduced influx of IL-1beta into the brain.     

A glycosylation-deficient endothelial cell mutant with modified responses to transforming growth factor-beta and other growth inhibitory cytokines: evidence for multiple growth inhibitory signal transduction pathways.

An endothelial cell line (M40) resistant to growth inhibition by transforming growth factor-beta type 1 (TGF beta 1) was isolated by chemical mutagenesis and growth in the presence of TGF beta 1. Like normal endothelial cells, this mutant is characterized by high expression of type II TGF beta receptor and low expression of type I TGF beta receptor. However, the mutant cells display a type II TGF beta receptor of reduced molecular weight as a result of a general defect in N-glycosylation of proteins. The alteration does not impair TGF beta 1 binding to cell surface receptors or the ability of TGF beta 1 to induce fibronectin or plasminogen activator inhibitor-type I production. M40 cells were also resistant to growth inhibition by tumor necrosis factor alpha (TNF alpha) and interleukin-1 alpha (IL-1 alpha) but were inhibited by interferon-gamma (IFN gamma) and heparin. These results imply that TGF beta 1, TNF alpha, and IL-1 alpha act through signal transducing pathways that are separate from pathways for IFN gamma and heparin. Basic fibroblast growth factor was still mitogenic for M40, further suggesting that TGF beta 1, TNF alpha, and IL-1 alpha act by direct inhibition of cell growth rather than by interfering with growth stimulatory pathways.